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Mature forests, litterfall and patterns of forage quality as factors in the nutrition of black-tailed… Rochelle, James Arthur 1980

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MATURE FORESTS, LITTERFALL AND PATTERNS OF FORAGE QUALITY AS FACTORS IN THE NUTRITION OF BLACK-TAILED DEER ON NORTHERN VANCOUVER ISLAND  by JAMES ARTHUR ROCHELLE B.Sc., Washington State U n i v e r s i t y , 1966 M.Sc, Washington State U n i v e r s i t y , 1968  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in FACULTY OF GRADUATE STUDIES (Faculty of Forestry) We accept t h i s thesis as conforming to the required standard  THE- UNIVERSITY. OF BRITISH COLUMBIA May, 1980  0  .-James A r t h u r R o c h e l l e , 1980'-  In presenting t h i s thesis in p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y a v a i l a b l e for reference and study. I further agree that permission for extensive copying of t h i s thesis for s c h o l a r l y purposes may be granted by.the Head of my Department or by his representatives.  It i s understood that copying or p u b l i c a t i o n  of t h i s thesis f o r f i n a n c i a l gain s h a l l not be allowed without my written permission.  r  Department nf  V ^ f W r ^  The U n i v e r s i t y of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  if\A.flLvc/W  \Z., l * l % 0  i i  ABSTRACT  The r e l a t i v e a v a i l a b i l i t y and quantities of b l a c k - t a i l e d deer (Odocoileus hemionus  columbianus  understory conifer  vegetation during winter  stands  Composition  [Richardson])  forage  were assessed  i n the Nimpkish Valley  and rates of l i t t e r f a l l  supplied by l i t t e r f a l l and i n selected mature  of northern Vancouver Island.  and i t s use by deer were determined  as were year-long food habits of deer u t i l i z i n g mature conifer and logged areas.  stands  Monthly patterns of v a r i a t i o n were determined over a  1-year period f o r a number of measures of forage quality including i n vitro  dry matter  cellulose, species,  digestibility  (DDM), crude  hemicellulose and l i g n i n .  known to be major dietary  protein,  cell  contents,  Analyses were made on ten forage items  of deer  i n the study  area.  Nutrient characteristics were compared between plants growing beneath a mature forest  canopy and i n cutover areas.  Rates of DDM f o r selected  species and DDM of a series of forage mixtures were determined.  Rela-  tionships of the various nutrient parameters to each other were examined. Energy contents as indicated by v o l a t i l e f a t t y acids (VFA) i n products of  i n v i t r o fermentation were determined  f o r the ten species examined.  Patterns of monthly and seasonal v a r i a t i o n i n concentration, composition and c a l o r i c content were defined and contrasts were made between forested and cutover areas of c o l l e c t i o n . including dry matter,  Characteristics of deer rumen contents  crude protein and c a l o r i c content were determined  monthly over a 1-year period, and related to deer food habits and nut r i e n t c h a r a c t e r i s t i c s of forage species. Deer condition throughout the year and i n r e l a t i o n to forage quality was assessed through determination of  weight and amounts of f a t deposited i n selected tissues.  Levels of  iii  b l o o d urea n i t r o g e n (BUN) were determined  r e l a t i v e to levels of protein  and energy i n t a k e and weight l o s s p a t t e r n s .  Amounts  of l i t t e r f a l l  suitable  as f o r a g e  equal  o r exceed  year-around  q u a n t i t i e s o f a v a i l a b l e r o o t e d v e g e t a t i o n i n some mature c o n i f e r s t a n d s . Lichens  made up 86 p e r c e n t  rates varied  i n response  of forage  t o weather  litterfall.  Monthly  conditions.  litterfall  Deer consumed  fallen  l i c h e n A l e c t o r i a and B r y o r i a spp. L i t t e r f a l l p r o v i d e s a r e l a t i v e l y s m a l l b u t c o n t i n u o u s source o f f o r a g e d u r i n g t h e w i n t e r .  Forbs of  and shrubs  deer.  during  were o f major and e q u a l importance  Epilobium  a n g u s t i f o l i u m was t h e most  the spring to f a l l  greatest i n winter.  i n t h e annual  heavily  p e r i o d ; use o f c o n i f e r s  used  diet  species  and l i c h e n s  was  Reduced f o r a g e a v a i l a b i l i t y i n w i n t e r was r e f l e c t e d  i n fewer s p e c i e s p r e s e n t i n rumen samples.  Forage  characteristics  changes i n t h e p l a n t .  varied  distinctly  i n response  to phehological  L i c h e n s were t h e most d i g e s t i b l e f o r a g e b u t con-  t a i n e d l e s s t h a n 2 p e r c e n t crude p r o t e i n .  Conifers contained less  than  t h e 7 p e r c e n t p r o t e i n r e q u i r e d f o r maintenance d u r i n g most o f t h e y e a r . Consistently areas of  higher nutrient levels  were n o t observed  i n p l a n t s from  d u r i n g any season  f o r e s t e d or cutover  of the year.  Digestibility  f o r a g e m i x t u r e s was h i g h e r t h a n expected from component d i g e s t i b i l i -  t i e s ; A l e c t o r i a sarmentosa had an enhancement e f f e c t on o t h e r components of mixed d i e t s . fill,  d r y matter  Most s p e c i e s were f u l l y d i g e s t e d w i t h i n 24 h o u r s . and crude  changes and deer f o o d h a b i t s .  protein  contents  reflected  forage  Rumen quality  iv  Energy l e v e l s o f f o r a g e p l a n t s v a r i e d s e a s o n a l l y i n response logical  change; E p i l o b i u m  angustifolium displayed the highest  c o n t e n t o f t h e s p e c i e s examined. content. VFA  t o pheno-  L i c h e n s and f e r n s were l o w e s t i n energy  Peak energy c o n t e n t i n most p l a n t s o c c u r r e d i n summer.  concentrations  followed  energy  the seasonal  p a t t e r n s observed  Ruminal  i n forage  p l a n t s ; peak c o n c e n t r a t i o n s o c c u r r e d i n s p r i n g and summer and were s i g n i f i c a n t l y higher than i n w i n t e r .  Maximum occurred  weights i n late  summer-early  fall  o f deer  occurred  winter.  Greater  i n fall-early weight  p e r i o d when energy  gains  winter  and minimums  occurred  i n the l a t e  demands above  maintenance  were  probably lowest.  Mesentery weight indicators. intake.  and k i d n e y f a t i n d e x appeared t o be s u i t a b l e c o n d i t i o n  B l o o d urea n i t r o g e n was a good i n d i c a t o r o f r e c e n t p r o t e i n  BUN l e v e l s d i d n o t i n c r e a s e d u r i n g p e r i o d s o f w e i g h t l o s s ,  gesting t i s s u e catabolism d i d not occur.  sug-  V  TABLE OF CONTENTS Page TITLE PAGE  . . . .  i  ABSTRACT TABLE OF CONTENTS  i i . . . . . . . . . . .  LIST OF TABLES LIST OF FIGURES  v. viii  .  ACKNOWLEDGEMENTS . . . . . . . . . . . .  CHAPTER I - MATURE FORESTS, LITTERFALL AND PATTERNS OF FORAGE QUALITY AS FACTORS IN THE NUTRITION OF BLACK-TAILED DEER ON NORTHERN VANCOUVER ISLAND — AN OVERVIEW . . . . Introduction Objectives Study Location Study Period •• Thesis Structure • L i t e r a t u r e Cited  x xii  1 ^ 3 3 8  9  CHAPTER II - LITTERFALL AND UNDERSTORY VEGETATION AS BLACKTAILED DEER FORAGE IN MATURE CONIFER STANDS Abstract Rationale and Objectives L i t e r a t u r e Review Methods . Results and Discussion . . . . . . . . . . . . . . . C h a r a c t e r i s t i c s of site/timber stands . . C h a r a c t e r i s t i c s of understory vegetation Amounts and nature of l i t t e r f a l l . . . . . . Consumption of l i t t e r f a l l by deer Relative A v a i l a b i l i t y of lichens and understory vegetation . . Summary . . . . . . . L i t e r a t u r e Cited  38 45 .47  CHAPTER I I I - FOOD HABITS OF BLACK-TAILED DEER, CHARACTERISTICS OF FORAGE PLANTS, AND RUMEN CHARACTERISTICS . . . . . Abstract . . . . . . Rationale and Objectives Food habits Characteristics of forage plants . . . . . . . Rumen c h a r a c t e r i s t i c s  50 50 51 51 52 53  10 10 11 12 20 24 24 .27 32 36  vi Page Food H a b i t s o f B l a c k - T a i l e d Deer L i t e r a t u r e review . . . . . . . Methods . . . . . . . . . . R e s u l t s and d i s c u s s i o n Summary - Food h a b i t s o f b l a c k - t a i l e d deer . . . . . . . . Forage C h a r a c t e r i s t i c s ' L i t e r a t u r e review Methods . . . . . . . . . . . . R e s u l t s and d i s c u s s i o n . . . . . . . . . . . . . . . . . . Dry m a t t e r Crude P r o t e i n . . . . . . . . . . Dry m a t t e r d i g e s t i b i l i t y (DDM) Rates o f d r y m a t t e r d i g e s t i b i l i t y . . . . . . . . . . F i b r e components o f f o r a g e p l a n t s NDF and c e l l c o n t e n t s A c i d - d e t e r g e n t f i b r e (ADF), a c i d - d e t e r g e n t l i g n i n (ADL) and c e l l u l o s e Hemicellulose . . . . S o l u b i l i t y of forage p l a n t s . . . . . . . . . . . . . D i g e s t i b i l i t y (DDM) o f f o r a g e m i x t u r e s . . . . . . . Summary - d i g e s t i b i l i t y , n u t r i e n t and fibre characteristics R e l a t i o n s h i p s between f o r a g e c h a r a c t e r i s t i c s . . . . . . . Rumen C h a r a c t e r i s t i c s L i t e r a t u r e review Methods . . . . . R e s u l t s and d i s c u s s i o n Dry m a t t e r c o n t e n t Rumen f i l l Crude p r o t e i n c o n t e n t Summary - rumen c h a r a c t e r i s t i c s . . . . Summary - Chapter I I I Food h a b i t s . . . . . . Forage c h a r a c t e r i s t i c s . Rumen c h a r a c t e r i s t i c s . . . . . . . . . . . . . L i t e r a t u r e Cited  CHAPTER IV - SEASONAL VARIATION IN ENERGY VALUES AND THEIR RELATIONSHIP TO OTHER CHARACTERISTICS OF FORAGE PLANTS OF BLACK-TAILED DEER . . . . . . . . . . Abstract R a t i o n a l e and O b j e c t i v e s L i t e r a t u r e Review . Methods R e s u l t s and D i s c u s s i o n VFA p r o d u c t i o n and energy v a l u e s o f f o r a g e p l a n t s . . . . C o m p o s i t i o n o f VFAs i n f o r a g e species R e l a t i o n s h i p o f VFA c o m p o s i t i o n and energy v a l u e to other n u t r i e n t c h a r a c t e r i s t i c s of forage p l a n t s . . . R e l a t i o n s h i p o f VFA c h a r a c t e r i s t i c s o f f o r a g e p l a n t s t o f o o d h a b i t s o f deer VFA c h a r a c t e r i s t i c s o f deer rumen c o n t e n t s Summary - Energy Values and VFA C o m p o s i t i o n o f Forage P l a n t s . L i t e r a t u r e Cited  53 53 55 57 63 66 66 77 84 84 96 105 109 112 112 136 141 143 145. 151 156 168 168 171 172 172 176 178 180 180 181 182 184 186  193 193 194 195 198 201. 201 220 226 231 232 236 239  vi i Page CHAPTER V - SEASONAL CHANGES IN CONDITION OF BLACK-TAILED DEER AND THEIR RELATIONSHIP TO PATTERNS OF FORAGE QUALITY . . Abstract R a t i o n a l e and O b j e c t i v e s . . .. L i t e r a t u r e Review Methods R e s u l t s and D i s c u s s i o n L i v e and f i e l d - d r e s s e d w e i g h t s Back f a t , mesentery f a t and k i d n e y f a t index ( K F I ) . . . . B l o o d - u r e a n i t r o g e n (BUN) - . Summary - Measures o f Body C o n d i t i o n and B l o o d Urea N i t r o g e n . L i t e r a t u r e Cited  248 253 257 262 266  CHAPTER V I - MATURE FORESTS, LITTERFALL AND PATTERNS OF FORAGE QUALITY AS FACTORS IN THE NUTRITION OF BLACK-TAILED DEER ON NORTHERN VANCOUVER ISLAND . . . . . . Summary and Management I m p l i c a t i o n s L i t e r a t u r e Cited .  269 .269 276  APPENDIX  241 241 242 243 245  277  vi i i  LIST  OF  TABLES Page  CHAPTER  II  Table  2-1.  Annual  Table  2-2.  Description  l i t t e r  Table  2-3.  Characteristics  Table  2-4.  Quantities  of  available  Table  2-5.  Components  of  l i t t e r f a l l  Table  2-6.  Alectoria  Table  2-7.  Heights  and  CHAPTER  production  of  study of  spp.  ground  plots  forage  coniferous  forests  vegetation  on  forage  suitable  as  during  the  study  on  .  28  . . .  30  .  .  .  .  .  .  .  . .  .  33  . .  .  .  37 .  Seasonal  comparisons  of  characteristics  of  3-2.  Seasonal  comparisons  of  characteristics  of  Table  3-3.  Characteristics  Table  3-4.  S t a t i s t i c a l  Table  3-5.  Rates  Table  3-6.  S t a t i s t i c a l  types and  collected  of  areas  types 3-9.  seasons nutrient  annual of  areas i n  .  .  .  .  fibre  of  of  cell  forage  contents  collected  in  different  comparisons  of  acid-detergent  of  lignin,  forage  comparisons collected  species  92 levels  of 97  at  3-10.  S t a t i s t i c a l  Table  3-11.  Dry  Table  3-12.  Dry  forage  of  comparisons different  and  from  forested  seasons  cellulose,  in  113  fibre,  and  hemicellulose 115  cell  components  forested of  cell  and  of  of  forage  cutover  components  forested  seasons  comparisons  and  areas  of  .  .  .  .  forage  .  annual  124 fibre  contents  of 139  d i g e s t i b i l i t y  matter  d i g e s t i b i l i t i e s increasing  of  forage of  mixtures  forage  proportions  146  mixtures of  Alectoria  sarmentosa 3-13.  Seasonal  compared Table  3-14.  Correlation  Table  3-15.  Correlation  fibre fibre  forages to  composition consumed  major  of  characteristics  and  by  forages  coefficients  cell  components  black-tailed  available annual forage  types  of  annual  nutrient  characteristics  of  forage  types  forested Correlation  Table  3-17.  Correlation  and  cutover  characteristics  of  forage  of  nutrient  of  157 and  from 158  of  characteristics  153 and  areas  coefficients coefficients  deer  nutrient  of  3-16.  of  . . .  coefficients  Table  fibre  150  nutrient  primary  118  cutover  species  matter  containing  110  neutral-  types  from  collected  Table  88  forested  .  comparisons  85  selected  areas  Statistical areas  different  .  species  content Seasonal  cutover  collected  of  d i g e s t i b i l i t y  acid-detergent 3-8.  at  and  species  types.  forage  .  vitro  cutover  Seasonal  forested  forage  forage  species  detergent 3-7.  from  comparisons  in  forage  and  of  cutover  forage  Table  39  III  3-1.  Table  .  sites  Table  Table  .  . . .  fenced  Table  Table  sites  forage  on  winter  study  sites  study  deer  accumulation on  13 25  rooted  plants  ...  .  l i t t e r f a l l  unfenced of  in  sites  shrub  seasonal  species  nutrient  types and  .  .  and .  .  .  .  .  .  .  159  fibre 160  ix  Page  Table  3-18.  Correlation  coefficients  characteristics Table  3-19.  Correlation  Table  3-20.  Regressions  of  coefficients  characteristics  3-21.  and  ferns  matter,  crude  protein,  content,  fibre  and  Seasonal  Monthly crude  Table  levels  of  protein  rumen in  levels  rumen  of  protein  in  of  dry and  f i l l  and  of  dry  contents  Seasonal  and  4-2.  Seasonal  annual  4-3.  Seasonal  values and  and  collected Table  4-4.  S t a t i s t i c a l  Table  4-5.  Correlations  Table  4-6.  Correlations  Table  4-7.  Seasonal  167  areas  .  .  .  .  .  173  .  174  .  203  and  black-tailed .  .  .  .  caloric  of  of  characteristics  of  comparisons and  black-tailed  types  .  .  .  .  .  and  .  .  .  .  .  associated  collected  VFA  in  for  of  forage  caloric  of  210  of  forage  species  and  nutrient  and  nutrient  .  .  221  types  content, VFA  .  values  VFA  and  species  areas  individual  content,  energy  production  cutover  forage of  and  types  206  of  forage  caloric  production forage  production  and  products  of  VFA for  values  forested  characteristics  227  VFA  species  230  concentration,  value  in  rumen  contents  deer  .  .  .  .  .  234  V  5-1.  Seasonal  patterns  parameters Table  5-2.  Correlations  Table  5-3.  Seasonal  and  of  measures levels  ruminal  in  and  black-tailed  Table  .  areas  levels  comparisons  composition  VFA  forage  caloric in  fermentation  CHAPTER  of  of  of  values  cutover  annual  associated  of  levels  caloric  comparisons  forested  Table  .  IV  4-1.  CHAPTER  .  black-tailed  matter  of  .  and  cutover  .  caloric Table  lignin  matter  rumens  forested rumen  cell  acid-detergent  f i l l ,  contents  collected  associated Table  162  acid-detergent  deer  CHAPTER  fibre  values  crude 3-22.  and  161  nutrient  forbs  fibre  d i g e s t i b i l i t y  deer Table  of  of  and  species  vitro  dry  of  nutrient  in  on Table  of  conifer  crude  selected  measures  of  morphological body  condition  in  deer selected of  body  of  blood  protein  249 morphological condition urea in  in  parameters  black-tailed  nitrogen  (BUN)  black-tailed  deer  .  .  255  and  deer  258  VI  6-1..  Seasonal by  characteristics  black-tailed  deer  of in  primary forested  forages and  consumed  cutover  areas  . . .  271  LIST  OF  FIGURES  Page  CHAPTER Figure  I 1-1.  Location on  CHAPTER Figure  of  the  northern  2-1.  Arrangement  Figure  2-2.  Snow  Figure  2-3.  Monthly  of  depths  the  l i t t e r f a l l  plots  at  relative  winter  depth  Figure  Valley  study  area  Island  4  II  collection  CHAPTER  Nimpkish  Vancouver  of  forage  and  the to  rooted  study  plant  forage  sites  height  .  .  .  .  .  .  .  21  during  1973-74  .41  l i t t e r f a l l  patterns  during  rates  the  and  study  snow  period  .  .  .  .  .  .  43  III 3-1.  Seasonal of  Figure  3-2.  Monthly  Figure  3-3.  Seasonal  Figure  3-U.  Monthly  of  patterns  forage  patterns  forage  forage forage  of  use  by  black-tailed  deer  types  58 of  use  by  black-tailed  deer  types  60  patterns species pattern  of  use  by  black-tailed  deer  . . . of  use  . by  black-tailed  deer  of .  .  .  .  62  of  species  64  Figure  3-5.  Average  annual  Figure  3-6.  Monthly  patterns  composition of  variation  of  forage in  Figure  3-7.  Monthly  patterns  of  variation  in  Figure  3-8.  Monthly  of  variation  in  Figure  3-9.  Solubility  Figure  3-10.  Monthly  types  98  composition  of  shrubs of  102 composition  conifers  ferns,  crude deer  103  patterns forbs and  levels protein  and  of  lichens  104  d i g e s t i b i l i t y  of  of  and  in  composition  rumen rumen  f i l l  plant  contents  dry of  dry  matter  matter  .  .  144  .  175.  and  black-tailed  xi Page  CHAPTER Figure  IV 4-1.  Monthly of  Figure  4-2.  Monthly  Figure  4-3.  Monthly  of of  patterns patterns  Seasonal  Figure  4-5.  Seasonal  Figure  4-6.  Seasonal  CHAPTER Figure  VFA VFA  caloric  conifer in  of  fermentation VFA  .  .  .  .  216  value  species  caloric  lichen,  .  .  .  217  value  forb  and  of  .  .  .  .  shrub  values species  caloric  of  and  products  species  caloric  of  and  products  composition  fermentation fern  and  products  composition  conifer caloric .  .  .  .  .  .  222  species  .  .  .  223  .  .  .  224 .  values  lichen, .  .  values  forb .  . . .  .  V 5-1.  Monthly  patterns  morphological body Figure  of  value  species  218  composition  fermentation  and  in  variation  products  caloric  shrub  species  4-4.  of  in  of  variation  products of  fermentation  Figure  of  of  patterns  variation  products  fermentation  fern of  of  fermentation  5-2.  Monthly  of  condition levels  ruminal  crude  variation  parameters in  of  in  and  black-tailed  blood-urea  protein  in  selected  measures  of  deer  nitrogen  250 and  black-tailed  deer  . . .  .  259  xii  ACKNOWLEDGEMENTS  A number of organizations and i n d i v i d u a l s provided assistance at various points between i n i t i a t i o n and this thesis i s a part.  completion of the graduate program of which  Dr. W.H.  Lawrence provided strong i n i t i a l  support  and guidance, and encouragement of various forms throughout the course of the work. the  effort,  helpful J.P.  Dr.  Fred L. Bunnell provided guidance  obtained  during  financial  thesis  Kimmins, D.M.  support  preparation.  Hebert, M.D.  counsel  as needed, and Graduate  Pitt  and  and  R.M.  was  committee  throughout  particularly members  Drs.  Strang provided valuable  input to the t h e s i s i n the form of questions, advice and suggestions. assistance  of Dr.  nutritional  their  Oh,  evaluation and  appreciated. S.K.  John  those of W.G.  shared  analysis,  Fellow students G.M.  Stephenson data.  who  The  helped  h i s expertise i n techniques  and  interpretation  Jones, R.D.  i n interpretation  efforts  of several  field  of  Ellis, results  of  A.S. by  assistants,  field  of  results Harestad  is and  f r e e l y sharing and  particularly  T u r n b u l l , are appreciated. The extra e f f o r t s of Joan Gelder  i n preparation of the manuscript were e s s e n t i a l to meeting involved.  The  the deadlines  My wife Barbara, and c h i l d r e n Denise, Mike and J u l i e were capable  aides, and p a t i e n t and constant supporters whose cheerful  acceptance  of other a c t i v i t i e s deferred was e s s e n t i a l to the completion of t h i s e f f o r t .  The  leave-of-absence  and  financial  assistance provided by  Weyerhaeuser  Company i s g r a t e f u l l y acknowledged, as i s the several types of support provided by the U n i v e r s i t y of B r i t i s h Columbia and the B r i t i s h Columbia and W i l d l i f e Branch.  Fish  Canadian Forest Products L t d . through Stan Chester,  generously provided f a c i l i t i e s f o r a f i e l d laboratory, and many other types of l o g i s t i c a l support.  1  CHAPTER I -  MATURE FORESTS, LITTERFALL AND PATTERNS OF FORAGE QUALITY AS FACTORS IN THE NUTRITION OF BLACK-TAILED DEER ON NORTHERN VANCOUVER ISLAND —  AN OVERVIEW  INTRODUCTION  E a r l y estimates indicated b l a c k - t a i l e d deer Odocoileus hemionus colurobianus populations (Richardson) were low i n mature c o n i f e r f o r e s t s on the west coast of the United States and Canada. ranged  from 0.4  (Cowan 1945)  to 6.0  Population estimates  deer per km  2  (Brown 1961).  Com-  parable estimates made by these i n v e s t i g a t o r s f o r areas containing a mixture of o l d forests and regenerating cutover land were approximately 10 to 23 deer per km . 2  More recent population estimates i n unlogged  areas of the east coast of Vancouver Island range from 13-38 km  2  deer per  (D. Hebert, pers. comm. 1979).  In areas where logging has conifer  stands  r e s u l t e d i n removal  of portions of mature  and where deep snows create severe winter c o n d i t i o n s ,  deer require timber stands f o r winter cover (Cowan 1956, Edwards Jones 1975).  Less snow accumulates  beneath c o n i f e r stands than on cut-  over areas, and deer movement i s less impeded i n such stands 1970,  Jones 1975).  1956,  (Telfer  A l s o , m i c r o c l i m a t i c conditions are ameliorated i n  timber stands, r e s u l t i n g i n more favorable s i t u a t i o n s f o r the conserv a t i o n of energy arboreal  lichens  (Moen 1968). and  for b l a c k - t a i l e d deer  Studies of food habits i n d i c a t e that  c o n i f e r f o l i a g e are important winter food (Cowan 1945,  Gates 1968,  Jones 1975).  items  Arboreal  lichens are a v a i l a b l e i n quantity only w i t h i n mature c o n i f e r stands.  2  It  is  likely  that  the  selection  In  British  stands  to  provide  also  of  is  Branch.  selection  of  stands  resulted of  from  as  valley  travel  during  on  the  management stands  logging  value  for  mature  harvest.  8-900  m  The plans  in  conifer  aid  preservation  Strips  need by  in  for  the  of are  these  Fish  and  production  guiding  as  which  elevation  potential  will  to  deer.  recommendations  deer.  variation  contribute  by  of  from  to  for  of  nutrient  stands  areas  importance  bottoms  review  and  conifer  the in  together  wintering  corridors  the  availability  as  selected  Information  mature  of  operating  winter  future habitat  deer.  Although tailed 1964,  several  deer Gates  in  species. data  of  assess  measures  should  of  the  changes of  nutritional  1975)  these  been  North  seasonal  of  type  seasonal  fying  Jones  and  examination  with  have  northwestern  Many this  studies  1968,  availability  An  has  reservation  aside  factors  recognition  deer  considered  its  these  conifer  extending  set  forage,  for  the  being  Wildlife  mature  wintering  timber  actions  of  Columbia,  for  mature  of  a l l  America  limited  variation  plants have  made  are  wide  of  quality  status  of  deer  is  nutrients to  the  habits Brown  1961,  available in  the  entire  of  blackCrouch  on  levels,  major  forage  Northwest  and  application.  in  quality  food  (Cowan 1 9 4 5 ,  common  in  forage  the  information  variation forage  of  physical  that range.  also  condition should  wildlife  of  deer  have  value  managers  associated in  could  identiuse  to  3 OBJECTIVES  This study was initiated to provide some of the basic information needs outlined above. Overall objectives of the study are:  1)  To determine the composition, quantity, quality and potential availability of forage supplied by understory vegetation and l i t t e r f a l l to black-tailed deer in mature conifer stands during winter.  2)  To determine the seasonal variation in chemical composition of deer forage plants and the nutritional significance of this variation relative to food habits and physical condition of deer.  3)  To determine levels and seasonal variation in energy produced by microbial fermentation in the rumen of black-tailed deer relative to metabolic energy requirements.  STUDY LOCATION  The study was  conducted  in the Nimpkish River Valley of north central  Vancouver  Island, British  Columbia  (Figure 1).  The  study  area is  contained  within Tree  Limited.  Specific research sites were located in the drainages of the  Farm License 39 of Canadian Forest Products,  Nimpkish River and two of i t s tributaries, the Woss and Davie Rivers.  F i g u r e 1.  L o c a t i o n of the Nimpkish V a l l e y study area on n o r t h e r n Vancouver I s l a n d .  5  The  study area l i e s w i t h i n the Coastal Western Hemlock B i o g e o c l i m a t i c  zone of K r a j i n a  (1965).  Within t h i s  zone s p e c i f i c study s i t e s were  located i n the western hemlock and salal-western hemlock a s s o c i a t i o n of the  glacial  climax  drift  land type  (Bell  overstory tree on these  1971).  sites.  Tsuga heterophylla i s the  Pseudotsuga  menziesii,  Thuja  p l i c a t a , Abies amabilis, Tsuga mertensiana and Chamaecyparis nootkatensis may occur i n a s s o c i a t i o n with Tsuga heterophylla, the l a t t e r two species p r i m a r i l y at elevations above 700 m.  Even-aged stands of Pseudotsuga  menziesii r e s u l t i n g from past w i l d f i r e s occurred i n large blocks a t lower elevations i n the v a l l e y .  U n t i l recent years logging a c t i v i t y was con-  centrated i n these stands, most of which have been harvested. S i t e index (height of dominant trees at 100 years of age) f o r P. m e n z i e s i i ranges from 24 to 60 m, with about 70 percent of the v a l l e y area having an average index of 42 m or higher (Bunce 1960).  Willms patterns  (1971)  described geologic h i s t o r y ,  i n the v a l l e y as summarized below.  physiography  and logging  The Nimpkish V a l l e y was  g l a c i a t e d i n the Pleistocene, and therefore the s o i l s are deep only i n the v a l l e y bottoms. areas.  Outcroppings of bedrock are common on the s i d e h i l l  Most of the v a l l e y area below 610 m i n e l e v a t i o n has been burned  by w i l d f i r e w i t h i n the past 1000 years.  Logging i n parts of the v a l l e y  began i n 1915; logging i n the study area i t s e l f began i n 1947 and continues at present.  The v a l l e y bottoms and some of the s i d e h i l l areas  were p r o g r e s s i v e l y c l e a r c u t , but a t present, most logging s e t t i n g s are separated by mature timber which i s l e f t unlogged years. 1220 m.  f o r a t l e a s t three  The Nimpkish V a l l e y i s mountainous, with many peaks higher than  6  The Nimpkish Valley experiences a moderate temperature range but extremes in precipitation.  Mean annual precipitation values for Woss Camp, about  100 m above sea level, ranged from 180 to 295 cm over a 15-year period; the average was 229 cm.  The six months between April and September ac-  count for only 23 percent of the total annual precipitation.  Precipi-  tation at Nimpkish Camp, also a valley bottom station, which is about 20 miles northwest of Woss, has a similar pattern. Farther south the annual variability in precipitation becomes greater.  This may be the result of  more variable terrain (Willms 1971).  Snow falls every year in the Nimpkish Valley at elevations above 300 m; snowfall may begin as early as November above 450 m and accumulates to varying depths until late spring.  With the exceptions of steep north  slopes, the snow line has usually retreated to about 900 m by the end of April.  On the north slopes snow remains until midsummer.  Snow depths may be substantial in some years, particularly at higher elevations. At Woss camp (100 m) average snowfall for the period 1954-73 was 8 cm in November, 39 cm in January and 3 cm in April.  During the  severe winter of 1971-72, 137 cm of snow f e l l at Woss Camp in December. Snow depths for forested and cutover areas over a range of elevations within the study area were reported by Jones (1975).  Temperature  extremes  minimum of -20°C. freezing.  at Woss Camp vary from a maximum of 37°C to a  No month has an average temperature which i s below  7  STUDY PERIOD  Collection of field data took place during the period August 1973 to October, 1974. Within this period, field work was divided into two major segments:  1)  Measurements made within selected  mature timber  stands to  assess quality and quantity of deer forage - October, 1973 to April, 1974.  2)  Collection and analysis of forage plants and deer in logged and timbered habitats for determination of seasonal patterns of  forage quality, deer food habits and nutritional status -  August, 1973 to October, 1974.  Facilities  for a field  laboratory were provided by Canadian Forest  Products, Ltd. at their Woss Lake Camp. Certain forage quality determinations were made in this lab concurrently with field work.  Other  analyses requiring more elaborate f a c i l i t i e s were made in the laboratories of the Animal Science Department at the University of British Columbia and Weyerhaeuser Company in Seattle, Washington. These analyses were conducted during 1975 and 1976.  8  THESIS STRUCTURE  The research findings reported in this thesis cover several aspects of the  interrelationship  between black-tailed  and  reading, and  subsequent publication of some portions, the thesis is  into  chapters  dealing with  of  their habitat, and  availability  organized  nutrient characteristics  deer,  specific  forage.  aspects  To  facilitate  of the work.  Abstracts and literature cited sections are provided for each chapter. The impetus for this work came from the observations of Jones (1975) suggesting mature forests, and forage l i t t e r f a l l they provide, were important to survival of black-tailed deer in severe winters. The approach I followed was to f i r s t examine the composition and rate of l i t t e r f a l l , and to quantify the rooted vegetation provided by selected mature forest types (Chapter II). The contribution of lichens and other major forage species to food habits of deer and the general nutritional value of these plants is treated in Chapter III. Chapter IV discusses energy content of selected forage species and Chapter V describes the annual cycle of physical condition in deer as related to patterns of availability and quality of forage as discussed in preceding chapters.  A summary chapter  (VI) considers the research and management implications of the overall study.  9  LITERATURE CITED Bell, M.A.M. 1971. Forest Ecology: In: Forestry Handbook of British Columbia. University of B.C. Forestry Club, Vancouver, pp. Brown, E.R. 1961. The black-tailed deer of western Washington. ington State Game Dept. Biol. Bull. No. 13. 124 pp.  Wash-  Bunce, H.W. 1960. A survey of forest regeneration in the Nimpkish Valley of British Columbia and recommendations for future management. M.S. Thesis. University of British Columbia. 208 pp. Cowan, I. McT. 1945. The ecological relationships of the food of the black-tailed deer, Qdocoileus hemionus columbianus (Richardson) in the coast forest region of southern Vancouver Island, B.C. Ecol. Monogr. 15: 109-139. Cowan, I. McT. 1956. Life and times of the coast black-tailed deer, pp. 523-617. In: Taylor, W.P. (ed.) The deer of North America. The Stackpole Co., Harrisburg, Pennsylvania. 668 p. Crouch, G.L. 1964. Forage production and utilization in relation to deer browsing of Douglas-fir in Tillamook Burn, Oregon. Ph.D. Thesis. Oregon State Univ., Corvallis. 162 pp. Edwards, R.Y. 1956. Snow depths and ungulate abundance in the mountains of western Canada. J. Wildl. Manage. 20: 159-168. Gates, B.R. 1968. Deer food production in certain serai stages of the coast forest. M.S. Thesis. Dept. of Zoology, Univ. of British Columbia. 104 pp. Jones, G.W. 1975. Aspects of the winter ecology of black-tailed deer (Qdocoileus hemionus columbianus [Richardson]) on northern Vancouver Island. M.S. Thesis, Faculty of Forestry, Univ. of British Columbia. 79 pp. Krajina, V.J. 1965. The biogeoclimatic zones and classification of British Columbia. Ecology of Western North America. 1: 1-17. Moen, Aaron N. 1968. Surface temperatures and radiant heat loss from white-tailed deer. J. Wildl. Manage. 32: 338-344. Telfer, E.S. 1970. Winter habitat selection by moose and white-tailed deer. J. Wildl. Manage. 34: 553-559. Willms, W.D. 1971. The influence of forest edge, elevation, aspect, site index and roads on deer use of logged and mature forest, northern Vancouver Island, B.C. M.S. Thesis, University of British Columbia, Vancouver. 184 pp.  10  CHAPTER II  LITTERFALL AND UNDERSTORY VEGETATION AS BLACK-TAILED DEER FORAGE IN MATURE CONIFER STANDS  ABSTRACT  Quantity and availability of black-tailed deer forage were examined with regard to the relative importance of understory vegetation and l i t t e r f a l l in mature conifer stands on northern Vancouver Island, B.C. in winter. Measurements were made of quantity and composition of l i t t e r f a l l  and  understory vegetation and rates of accumulation and consumption of l i t t e r f a l l by deer.  Lichens, primarily Alectoria sarmentosa and Bryoria  spp. made up 86 percent of l i t t e r f a l l suitable as deer forage; the remainder was  conifer  foliage.  During  the winter, forage potentially  available as l i t t e r f a l l approaches or exceeds amounts provided by understory vegetation. litterfall  In mid-elevation timber stands combined weights of  and rooted forage measured during winter approach or exceed  quantities reported in several other studies in western North America for  cutover areas at maximum levels of forage production. Monthly rates  of  litterfall  varied,  apparently  in response  to individual  storms.  Limited tests with exclosures indicated deer consume fallen Alectoria and Bryoria spp.  Rumen analyses of deer collected in timber stands indi-  cate the major component of forage l i t t e r f a l l , A- sarmentosa, is a major dietary item in winter.  Snow depths in timber stands were half those  measured in cutover areas.  Results suggest that mature timber stands  serve as c r i t i c a l winter range during winters with deep snow, during which time l i t t e r f a l l provides a continuing source of winter forage.  11  CHAPTER II  LITTERFALL AND UNDERSTORY VEGETATION AS BLACK-TAILED DEER FORAGE IN MATURE CONIFER STANDS  RATIONALE AND OBJECTIVES  Arboreal lichens, made available through l i t t e r f a l l , are major items of winter food of black-tailed deer on Vancouver Island (Cowan 1945, Gates 1968,  Jones 1975).  Deep snow reduces the availability of understory  vegetation and restricts mobility of deer (Telfer 1970), particularly i n recently logged areas, where greatest snow depths occur.  Jones (1975)  observed concentrations of deer in mature conifer stands during periods of deep snow. L i t t e r f a l l may be a more important source of deer forage than understory vegetation during these periods of deep snow. information  is available  on  the  characteristics  of l i t t e r f a l l  Little with  respect to its value as deer forage.  To address the question of quantity and relative availability of forage, several objectives were established:  1)  To quantify amounts of l i t t e r f a l l  potentially available to  black-tailed deer in mature forests during the winter period. 2)  To assess amounts of l i t t e r consumed by deer.  3)  To quantify amounts of understory vegetation potentially available to black-tailed deer in mature forests in winter.  Nutritional value of forage to deer is treated in Chapters III, IV and V.  12  LITTERFALL - ITS CHARACTER AND VALUE AS UNGULATE FORAGE  PATTERNS OF LITTERFALL IN WESTERN CONIFEROUS FORESTS  L i t t e r f a l l , through the natural shedding of foliage, reproductive structures, and other plant parts, as well as storm-caused breakage of epiphytes, branches, and bole portions of trees, is a major pathway for the transfer of both energy and nutrients in the forest ecosystem. Numerous studies have examined the contribution of l i t t e r f a l l to the input and cycling of nutrients within forest stands.  (For summary of early studies  see Bray and Gorham 1964.) Studies in western North America are few and include those of Tarrant  et a l . (1951) in stands of Thuja plicata,  Pseudotsuga menziesii, Tsuga heterophylla and Abies amabilis, Hurd (1971) in stands of Tsuga heterophylla and Picea sitchensis, Abee and Lavender (1972) in mature P. menziesii and Rickard menziesii.  (1975) in second-growth P.  Further east, in Colorado, Moir (1972) measured l i t t e r f a l l  in Pinus contorta stands.  The pattern of deposition of l i t t e r of conifers was and  Gorham  throughout  (1964) as the  year.  ranging In  from  distinctly  old-growth P.  summarized by Bray  seasonal  menziesii,  Lavender (1972) found that the vast majority of l i t t e r winter but that needle cast was  to variable  stands Abee  and  f e l l during the  greatest during the f a l l .  Grier and  Logan (1977) noted variation among species in time of peak l i t t e r f a l l , and  that T. heterophylla  September.  leaf l i t t e r f a l l  was  greatest in August and  Moir (1972) observed that P. contorta shed needles continu-  ously throughout the year.  13  Table  2-1.  Annual  litter  production  Moss  Age (vrs)  Coniferous  Type  Stand  Pseudotsuga  Needles  -  45  and  coniferous  forests  -  metric  tons  • ha  Twigs,  Hardwood Leaves  Conifer  in  Bark and Wood  -  Reproductive  Green  Structures  -  Leaves  ReferOther  Lichens  -  --  -  -  -•  -  -  -  Total  -  ences  1.8  (  1)  1.4(48)  2.9  (  2)  -  0.7(24)  2.9  (  2)  -  -  5.9  (  3)  -  0.4(10)  3.9  (  4)  2.0  (  5)  2.2  (  5)  1.8  (  5)  1.1  ( 5 )  --  2.9  (  6)  -  4.6  (  7)  0.08(7)  l . l  (  8)  • -  -  (  9)  menziesii  Pseudotsuga  -  40  1.5  (52)  33  2.2  (76)  mature  2.8  (47)  0.4  (  6)  2.0(33)  0.7  (14)  mature  1.9  (48)  0.5  (13)  0.6(16)  0.5  (13)  a  menziesii  Pseudotsuga  -  -  menziesii  Pseudotsuga menziesii  Pseudotsuga  0.02(<1)  menziesii  Pseudotsuga  -  350  -  -  -  -  -  • -  -  -  menziesii  Thuja  plicata  not  given  Abies  amabilis  not  given  not  given  Tsuga  -  - •-  -  heterophylla  Picea  sitchensis/  =150  —  "*"  • Tsuga  -  -  (18)  -  heterophvlla  Pinus  contorta  78  Tsuga  3.2  mature  -  (68)  0.17(15)  0.01  (1)  0.6(14)  0.8  0.6(55)  0.16(15)  -  0.01(1)  0.08(7)  b  heterophvlla  Pseudotsuga  -  50-130  -  -  —  (16)  menziesii/ Pinus  Pinus  -  0.10  c  engelmannii  contorta  (cool  -  all  2.5  (66)  d  temperate  (  d  9)  -  d  (6)  d  3.4  (10)  forests)  a  percent-of  total  litterfall only  lichen  litter e  ( l ) (6)  litterfall.  measurements litterfall  component  Dimock, Hurd,  figures  1958;  1971;  made was  (2)  (7)  are  Will,  Moir,  only  during  winter  -  tabular  values  represent  a  180-day  litterfall  period,  studies  Bray  measured. approximate 1959;  1972;  (3)  (8)  values  Abee  This  and  study;  as  reported  Lavender, (9)  for  1977;  Edwards,  et  4  conifer  (4)  Crier  al.  litterfall (in  (1960);  press); (10)  Bray  (5) and  by  Tarrant, Gorham,  et  and  Gorham  al.  (1951);  19657  (1964).  14  A major influence i n the timing of l i t t e r f a l l forests  i s the pattern of winter  storms.  attributed most of the total l i t t e r f a l l  in temperate and boreal  Abee and Lavender (1972)  in winter to breakage under the  weight of the snow. Will (1959) found f a l l of non-needle l i t t e r of P. menziesii was influenced by storms. Although Pike et a l . (1972) did not measure l i t t e r f a l l ,  they speculated that the heavy weight of epiphytes  on branches, which probably increased three to four times when wetted by precipitation, was a significant factor affecting branch f a l l .  Cowan (1945) and Gates (1968), working on Vancouver Island, B.C., noted that arboreal lichens were made available to black-tailed deer by strong winds and snow damage to mature trees. caribou  Lichens were made available to  (Rangifer articus) in British Columbia during winter both by  f a l l of entire trees and of individual lichens (Edwards et al. 1960).  ARBOREAL LICHENS AND CONIFERS AS UNGULATE FORAGE  The  importance of arboreal lichens as food for caribou and reindeer  (Rangifer spp.) is well-established. made up 54 percent  of the winter  In Newfoundland arboreal lichens diet of caribou  (Bergerud  1972).  Cringan (1957) noted the importance of arboreal lichens to caribou and their becoming available in winter through the f a l l of dead trees. He theorized that this constituted a mechanism for a sustained supply of essential  food,  the supply  of which could not be affected through  increases in caribou population.  Edwards et a l . (1960) suggested that  the f a l l of individual lichens and dead trees bearing lichens provided significant  quantities of caribou forage.  Schroeder (1974), however,  15  discounted the importance of l i t t e r f a l l as caribou forage in northern Washington and southern British Columbia. Rapid accumulation of snowfall, decreased palatability of lichens due to mildew, and caribou preference in the spring  for green forbs and shrubs over mildewed lichens were  suggested as reasons for the low importance of fallen lichens.  Winter use of arboreal lichens by elk, Cervus canadensis nelsoni, has also been observed.  C l i f f (1939) reported the use of Alectoria fremontii  by elk in winter in the Blue Mountains of Oregon.  Kufeld (1973) sum-  marized C l i f f ' s findings, rating this species as low in value compared to other elk forage plants.  Hash (1973) found that arboreal lichens  made up 2.4 percent of the winter diet and occurred in 35 percent of 57 elk rumens collected in northern Idaho.  Hash did not give the scientific  name of the lichens, but other investigators working in this region indicate they are probably of the genus Alectoria (T. Leege, personal communication,  1975).  Black-tailed deer are known to feed on arboreal lichens.  Cowan (1945)  observed that Usnea barbata constituted 36 percent by volume of the food items present in the rumens of black-tailed deer in winter.  He specu-  lated that much of this lichen was obtained by feeding on fallen limbs broken from mature P. menziesii trees by wind and snow. This lichen was apparently a preferred  food as i t s occurrence in the diet was much  greater than i t s availability to deer in the environment.  Gates (1968)  found that arboreal lichens made available by strong winds and snow or logging damage to mature trees constituted 13 percent of the winter diet of black-tailed  deer and  ranked as the third most important forage  16 species during winter. In the 2 years of his study, Jones (1975) working in the Nimpkish Valley of Northern Vancouver Island, B.C., observed that the arboreal lichens, Alectoria spp. were the fourth most abundant food item in winter-spring rumen samples of black-tailed deer, constituting 6 percent of the total volume of identifiable items. Washington, 0.  both  white-tailed  hemionus make relatively  deer  0.  virginianus  heavy use of Alectoria  (D. Pridmore, personal communication,  1975).  In north central and mule  deer  spp. in winter  Book et a l . (1972) noted  year-long use of several species of arboreal lichens by black-tailed deer  i n northwestern  California.  Greatest use occurred i n winter;  lichens were made available primarily through dislodgement by wind.  In contrast to the above findings, Taber (personal communication, 1975) noted that black-tailed deer/mule deer hybrids did not utilize lichens in significant amounts during winter in the Ross Lake area of Washington, even though Boehm (1972) determined that lichens were quite abundant on the winter range.  Jones  (1975) found that foliage of T. plicata, P. menziesii and T.  heterophylla made up approximately 36 percent of the winter diet of black-tailed  deer on Vancouver  Island.  In western Washington, Brown  (1961) found that the same species made up 13 percent of the winter diet. P. menziesii made up 47 percent of the winter diet in central Vancouver Island (Cowan  1945).  The source of this foliage, i.e. young trees or  l i t t e r f a l l , was not determined.  The heavy feeding observed on fallen  limbs by Jones (personal communication,  1974) suggests l i t t e r f a l l is of  some importance as a source of foliage.  Kufeld et a l . (1973) cite a  number of studies in which moderate use of P. menziesii and other coniferous species was determined for mule deer, 0. h. hemionus, in winter.  17  Mosses are present in l i t t e r f a l l and as rooted forage but receive l i t t l e use by deer.  Trace amounts of mosses in black-tailed deer rumen contents  were reported by Brown (1961) and Jones (1975).  These minor amounts are  probably accidentally ingested by deer feeding on other plants.  In his review of food habits of Rocky Mountain elk, Kufeld (1973) cited several studies which reported the presence rumen contents, primarily in winter.  of coniferous foliage in  Kufeld rated conifers as low value  forage and made no distinction between l i t t e r f a l l and rooted plants as foliage sources.  Cowan et a l . (1950) reported winter use of several species of conifers and the lichen, Usnea barbata, by moose (Alces americana) in western Canada.  Crete and Bedard (1975) found that Abies balsamea represented  slightly more than 50 percent of total winter browse of A. alces in Quebec. The conifers, Abies lasiocarpa and P. menziesii^ were utilized in  f a l l and winter, respectively by A. a. shirasi in Montana (Stevens  1970).  These investigators did not indicate i f l i t t e r f a l l was a source  of this moose forage.  LITTERFALL AS UNGULATE FORAGE  Several of the studies of food habits of ungulates reviewed above indicate that lichens and conifer foliage are important food items, particularly in winter, and that l i t t e r f a l l is probably an important source of this forage.  18  Among the many studies which provide quantitative measures of l i t t e r f a l l , the proportion of l i t t e r which might serve as forage for ungulates was assessed only by Edwards et a l . (I960). The components of l i t t e r which are forage items include green coniferous foliage, mosses and lichens. Individual conifer needles, even i f green at the time of shedding, would not be suitable as forage because of the difficulty deer would encounter in picking them up. Deciduous angiosperm leaves have been suggested as a winter  food  source  for white-tailed  deer  (Harshbarger  and McGinnes  1971).  POTENTIAL AMOUNTS OF LITTERFALL FORAGE IN CONIFEROUS STANDS  Amounts of l i t t e r f a l l documented by studies in western North America are summarized in Table 2-1. Few studies have dealt specifically with the portions ungulates.  of l i t t e r f a l l  that  potentially  would  provide  forage for  Studies treating ungulates have concentrated on estimating  amounts of lichen present in the forest canopy and are discussed below.  Edwards et a l . (1960) made quantitative measurements of arboreal lichen biomass and estimated the portion available to caribou. They measured total lichen loads ranging from 280 to 3290 kg ha . Depending on snow 1  depth, which greatly influences height of caribou feeding in trees, available lichens ranged from 12 to 316 kg ha . Mortality and windfall 1  of trees provided an estimated 82 kg ha  1  of lichens in a conifer stand  supporting a total lichen load of 750 kg ha . Measurements of accumu1  lated lichens suggested that about 21 kg ha  1  may be available on the  ground in the spring. Schroeder (1974) determined total arboreal lichen  19  biomass in mixed Picea-Abies, and in Larix occidentalis stands to range from 103 to 431 kg ha . 1  Estimates of the portion available to caribou  ranged from 56 to 284 kg ha" . 1  About 8.0 to 274 kg ha"" per year of 1  lichen f e l l annually, based on summer measurements which probably underestimate actual quantities.  Scotter (1971) reported that Picea mafiana and Pinus banksiana stands in Saskatchewan carried a standing crop of arboreal lichens of 1200  and  2053 kg ha , respectively, of which 680 and 380 kg ha" , respectively, 1  1  were available to caribou.  Based on calculations  from the work of Edwards et a l . (I960); Pike  (1971) , and Pike et a l . (1972) reported annual turnover of epiphytic lichens to be 5 to 25 percent of total biomass.  These investigators  estimated an epiphytic lichen biomass of about 9.4 kg on a single oldgrowth P. menziesii tree in western Oregon.  In stands containing 60  such trees per hectare, 600 kg of lichens would be present.  Denison  (1972) , working in the same stand, estimated amounts of the foliose lichen, Lobaria oregana at about 450 kg ha kg ha  1  1  and estimated that about 90  of this f e l l as l i t t e r , mainly during winter.  With respect to conifer foliage biomass, Pike et al. (1972) estimated 84 kg foliage per old-growth tree or 5040 kg ha  1  based on 60 trees per  hectare. Turner and Cole (personal communication, 1975) summarized the world  literature  on biomass of forest  stands.  Studies cited for P.  menziesii stands aged 28 to 75 years indicate needle biomass ranging from about 5000 to 16,000, with a mean of about 10,000 kg ha" . 1  20  STUDY METHODS  Field measurements of l i t t e r f a l l  were made during the period October,  1973 to April, 1974. The original study plan included the selection of three locations i n each of the elevation zones: (1) 150-450 m, (2) 450760 m, and (3) 760-1070 m.  High levels of snow f a l l i n late October,  coupled with a limited amount of time for field installation prevented establishment  of study sites in the upper elevation zone.  Two sites  were established i n the 450-760 m zone and three sites were established in the 150-450 m elevation zone.  Representative study sites were arbi-  trarily selected within timber stands based on field examination of the general  characteristics  of the stand within the elevation zone.  An  attempt was made to select sites of similar slope and aspect.  At each of the five sites a starting point for the layout of a grid of 25 plots was selected at the point where an object thrown backwards over the investigator's head came to rest.  From this starting point, marking  the center of plot number 1, additional serially-numbered plot centers were located. A stake marked each plot.  The study site was laid out in the form of a square, 50 m on a side, with plot centers equidistantly spaced at 12.5 m (Figure 1). Total site area was 0.25 hectares. occurring on a 4-m  2  and  canopy  (1959).  At each plot center, a l l species of vegetation  circular plot were identified and their height class  coverage  recorded  following the technique  of Daubenmire  Current annual growth was clipped on a l l vegetation less than  137 cm in height and known from previous food habits studies to be  ^ L i t t e r t r a p - lm^  Vegetation plot 16  14  17  12.5m 8 l k—12.5m—1>  10  f4-  1  3  18  12  19  11  20  50m  F i g u r e 2-1. Arrangement of l i t t e r f a l l and rooted forage c o l l e c t i o n p l o t s a t the study sites.  25  22  u t i l i z e d as forage by deer. taken  These samples were placed i n p l a s t i c bags,  to the laboratory and weighed  and a composite sample of each  species was oven d r i e d .  Following forage plant c o l l e c t i o n , each p l o t center was provided w i t h a 1-m  square l i t t e r  trap.  Trap frames were constructed of cedar l a t h ,  over which was stapled a sheet of 4 m i l . polyethylene.  On slopes, traps  were supported i n a h o r i z o n t a l p o s i t i o n by b u i l d i n g up the low side w i t h sections of logs and limbs a v a i l a b l e on the s i t e .  A 10-plot sample was randomly chosen from the 25 p l o t s f o r determination of monthly l i t t e r f a l l rates.  A l l s i t e s were v i s i t e d each month during  the snow period and an a d d i t i o n a l l i t t e r trap was placed d i r e c t l y above the e x i s t i n g trap on these proximately  10 p l o t s .  L i t t e r f a l l was measured f o r ap-  6 months (October to A p r i l ) on s i t e s 1, 2 and 3, 4 months  (December to A p r i l ) on s i t e 4, and 3 months (January to A p r i l ) on s i t e 5.  L i t t e r was  c o l l e c t e d as snow melted i n the spring and frozen f o r  subsequent analyses.  Analyses involved separation of accumulated l i t t e r  on each trap i n t o the f o l l o w i n g categories:  Forage Items  Non-forage Items  Lichens  Conifer needles  A l e c t o r i a spp.  1  Lobaria oregana  Bark  "Purple" l i c h e n  Branches  (Platismatia herrei,  Twigs  P. lacunosa, Hypogymnion  Angiosperm leaves  enteromorpha)  Moss  Sphaerophorus globosus  a  Cones  Wood  S i n c e t h i s study Brodo (1977) has revised the taxonomy of A l e c t o r i a and a few samples are of the genus B r y o r i a .  23  Forage Items  Non-forage Items  Green Conifer Foliage  Residue  Tsuga heterophylla  Other  Thuja plicata Pseudotsuga menziesii Abies amabilis  Individual l i t t e r components from each trap were placed in labelled paperbags, dried in a forced-air oven at 60°C for 24 hours and weighed.  Additional measurements taken at each site included:  Canopy closure - determined with a spherical densiometer (Lemmon 1957). Measurements were taken directly above each of the 25 plot centers at each site.  Elevation - determined with an altimeter.  Aspect - general direction determined with a compass.  Snow depth - estimated by taking one or more measurements at the time of monthly visits to each site.  Composition and diameter of tree species, trees per hectare determined by total count and diameter measurement of a l l trees 5 cm and greater DBH on each site.  24  Wood Volume by species - Gross tree volumes were calculated from diameter measurements and a sample of height measurements of each species made with a Suunto clinometer.  The sample of tree heights was  selected to cover the range of diameters present.  Gross volumes  were calculated based on B.C. Forest Service (1962) Standard Cubic Foot Volume Tables.  Total basal area -  determined by taking prism plots using a 40 BAF prism  at a minimum of five different points.  Analyses were made of food habits of deer collected in timber stands and cutover areas throughout the year.  A rumen content sample of approxi-  mately 1000 ml. was taken from each deer and subsequently analyzed at the B.C. Fish and Wildlife Branch  lab in Victoria, B.C. Following  washing of the sample over 5.66 and 4.00 mm screens, residues were separated into species and quantities determined volumetrically. Species occurring at less than 0.5 ml were assigned a trace value. Frequency of occurrence of a l l items was recorded.  RESULTS AND DISCUSSION  CHARACTERISTICS OF SITE/TIMBER STANDS  Descriptions of the physical characteristics of the study sites and measurements of the timber stands are presented in Table 2-2.  Sites 1,  3 and 4 are classed as low-elevation stands (below 450 m); sites 2 and 5 are mid-elevation stands (450-760 m). Sites 2, 4 and 5 were on southfacing aspects; sites 1 and 3 were on west-northwest respectively.  and west aspects,  Table 2-2.Description of the study sites. Site Number JW Elevation  Mid-elevation  1  3  4  2  5  Elevation (m)  343  282  435  732  610  Aspect Slope %  WNW 25%  W .17%  SE 28%  S 65%  S 45%  Crown Closure (%)  95.0  96.0  98.0  94.0  94.0  9 -1 Basal area (m *ha )  66  101  96  80  74  479 38  1087 36  1294 18  857 21  Site Characteristic  '  z  Trees/hectare x ht. sample trees (m) Stand Composition (%)/ x diameter (cm) Pseudotsuga menziesii Tsuga heterophylla Thuja p l i o a t a Abies amabilis  531 35 2/130 33/31 11/86 54/18  Gross Wood Volume (m «ha -*-)  17/79 78/28 . 5/81 0/0  6/97 85/15 9/74 0/0  7/58 58/28 35/18 >l/7  10/69 69/28 22/36 0/0  3  Pseudotsuga  menziesii  Tsuga heterophylla Thuja Abies  Total  plioata amabilis  > 5.6 0.9  6.2 8.6 1.5 -  9.0 5.0 7.0 -  1.7 3.5 0.9 0.6  1.4 4.0 1.2  13.7  16.3  21.0  6.7  6.6  2.6  4,6  26  Crown closures on the five sites ranged from 94 to 98 percent.  There  were no consistent differences between mid- and low-elevation sites with respect to crown cover.  This may have been a function of the technique  used and the nature of the mid-story vegetation.  Use of the spherical  densiometer involves counting of portions of a grid, reflected on a mirror, that are not occupied by foliage.  On a l l sites coniferous trees  were present in mid-story positions and their crown coverage was necessarily  included in canopy measurements.  It is likely that mid-story  trees produce different effects in terms of shading and snow retention than overstory trees.  Visual examination of mid-elevation stands sug-  gested that overstory canopies were less dense than low-elevation stands. However, this apparent difference in canopy density may be a result of the greater slope percentages, 55 percent on mid-elevation sites compared to 23 percent on low-elevation sites, which allowed greater amounts of light  to reach the ground.  Jones (1975) noted that overstory crown  closure was inversely related to elevation although this relationship was not statistically significant.  Basal area ranged from 66 to 101 m ha , with a mean of 77 on mid2,  1  elevation sites compared to 88 on low-elevation sites.  In  low-elevation  stands  an average of 699 trees greater than 5 cm  diameter at breast height were present per hectare; mid-elevatiori plots had a mean of 1076 trees per hectare.  T. heterophylla was the most abundant tree species on four of the five study sites.  P. menziesii occurred on a l l sites mainly as large older  27  trees, probably disturbance.  remnants of a stand which had developed  following past  T. heterophylla was the most common understory species on  four of the five sites and would l i k e l y dominate the climax overstory.  Gross wood volumes ranged from 660 m *ha 3  1  on s i t e 5 to 2100 m *ha 3  s i t e 4. Mean volume for mid-elevation sites was 665 m ha 3,  1  1  on  compared to  a mean of 1700 m ha  1  On  combined, P. menziesii, T. heterophylla, T. p l i c a t a  3,  the f i v e  sites  on low-elevation s i t e s .  and A. amabilis contributed 33, 40, 25 and 2 percent, respectively, of the t o t a l wood volume.  The  study sites apparently were at the lower elevational l i m i t s of d i s -  tribution  of Tsuga mertensiana as reflected  by the occurrence of only a  few individuals of this species.  CHARACTERISTICS OF UNDERSTORY VEGETATION  Table 2-3 summarizes frequency of occurrence and density measurements of understory species occurring on the study s i t e s .  The mosses S t o l c e s i e l l a  oreganum and Hylocomium splendens occurred at high frequencies and r e l a t i v e l y high densities on a l l s i t e s .  Shrubs, which make up the bulk of  rooted forage available, occurred at moderately high densities and f r e quencies same  only on mid-elevation  general  area,  Jones  sites.  (1975)  In mature timber  reported  Vaccinium spp. with increased elevation.  an increase  stands  i n the  i n cover of  28 Table 2-3. C h a r a c t e r i s t i c s of ground v e g e t a t i o n on study  sites.  Lou—elevation S i t e s 1  ( S i t e Number): Coverage  i  3 " b quency F r e  Coverage  Mid-elevation Sites ... -  4 Frequency  Coverage  Frequency  —  2  Frequency  Covera ge  ...  5  Coverage  Frequency  TREE SEEDLINGS: Abies amabilis  1  8.0  -  Thuja p l i c a t a  1  4.0  1  16.0  Tsuga h e t e r o p h y l l a  2  92.0  2  100.0  Abies a m a b i l i s  1  8.0  -  -  -  Thuja p l i c a t a  -  -  , 1  4.0  1  12.0  Tsuga h e t e r o p h y l l a  1  4.0  1  36.0  1  Pseudotsuga m e n z i e s i i  -  -  1  4.0  -  -  -  -  -  -  -  -  ]  4.0  1 •  1  84.0  -  -  8.0  r  76.0  -  -  -  i  12.0  TREE STEMS: -  1  12.0  44.0  1  4.0  i  24.0  -  1  4.0  i  8.0  SHRUBS: 100.0  Gaultheria shallon  -  -  1  4.0  1  20.0  3  100.0  Vaccinium alaskaense  1  48.0  1  60.0  1  8.0  2  96.0  Vaccinium p a r v i f o l i u m  1  76.0  2  100.0  1  88.0  2  96.0  1  4.0  -  -  1  8.0  -  -  -  -  -  -  -  -  -  -  1  36.0  1  4.0  3 .  1  88.0  2  100.0  FORBS: Achlys  triphylla  Chimaphila  umbellata  Clintonia uniflora  -  -  -  -  1  4.0  -  -  -  Cornus canadensis  1  12.0  1  24.0  -  -  -'  -  1 .  Goodyera o b l o n g i f o l i a  1  16.0  1 •  12.0  1  4.0  1  12.0  1  20.0  Linnaea b o r e a l i s  1  4.0  1  4.0  1  4.0  1  4.0  1  4.0  Lactuca sp.  -  -  -  -  1  4.0  -  -  -  -  Monotropa sp.  -  -  -  -  1  4.0  -  -  1  4.0  -  8.0  Montia s i b e r i c a  -  -  -  1  64.0  -  -  1  24.0  Pyrola sp.  1  4.0  1  40.0  1  16.0  1  4.0  1  28.0  Tiarella trifoliata  -  -  -  -  1  12.0  -  -  -  -  -  -  1  8.0  -  -  -  • • -  -  -  Blechnum s p i c a n t  1  16.0  -  -  -  Polystichum muniturn  -  -  -  -  V i o l a sp.  .  •  FERNS: -  -  -  -  -  4.0  -  -  -  -  -  MOSSES: -  S t o l c e s i e l l a oreganum  3  100.0  -  -  2  72.0  Hylocooium splendens  3  96.0  3  100.0  2  96.0  3  100.0  Khytiadelphus  loreus  -  -  2  88.0  2  96.0  -  Rhytidiopsis  robusta  1  16.0  1  20.0  1  36.0  1  4.0  -  -  3  100.0  -  2  84.0  40.0  2  96.0  1  28.0  OTHER: Down logs  1  16.0  2  64.0  2  64.0  1  Rotten wood  1  24.0  1  24.0  1  36.0  -  Exposed rock  -  "Coverage c l a s s e s  -  -  -  -  -  1  f r e q u e n c y = Frequency o f occurrence =  Class  % Canopy Coverage  1 2 3 4 5 6  0-5 5-25 25-50 50-75 75-95 95-100  -  4.0  11 P  total° lots C  ed  x  1 0 0  29  Among  shrubs  on  mid-elevation sites,  Gaultheria shallon,  Vaccinium  parvifolium and V. alaskaense were most abundant, with canopy coverages of  37.5,  15 and  8 percent, respectively.  On low-elevation sites, a  maximum shrub coverage of 15 percent (V. parvifolium) occurred on site 3.  In  180-  to  200-year-old  timber  stands  at  low-elevation in central  Vancouver Island, a generally drier region than the Nimpkish Valley, Gates  (1968) reported G^ shallon was  the dominant understory shrub,  covering 65 percent of the ground surface.  Since measured overstory crown closures were not different between midand low-elevation sites, crown closure does not help explain differences in abundance of understory shrubs.  A reduction in understory vegetation  biomass with increasing crown closure has been documented for G. shallon (Long and Turner 1975). Jones (1975) also found an inverse relationship between crown closure and coverage  of Vaccinium  spp.  The  difficulty  encountered in measuring crown cover with the spherical densiometer, as discussed earlier, is probably responsible for failure to record variation in crown cover, since cover clearly seemed to be lower on mid- than on low-elevation sites.  Dry weights of forage plants as determined in clipped samples from sites 1-5 are presented in Table 2-4. available  The data indicate the standing crop of  forage in the absence of snow.  Quantities of shrub forage  were greater in mid- than in low-elevation stands.  Oven-dry weights of  forage available, less than 1.4 m in height, ranged from 7.4 to 224.8 kg'ha  1  on the five sites.  Mean forage weights of 41.7 and 152.7 kg'ha  1  Table 2-4. Q u a n t i t i e s of a v a i l a b l e rooted forage on the study (current year's growth i n kg.ha" dry weight).  sites  1  S i t e Number Low-elevation  Mid-elevation  Tree Seedlings  Tsuga heterophylla Thuja plioata Pseudotsuga menziesii  76.5 -  14.6 0.1 -  4.9 0.02 -  Sum o f t r e e seedlings  76.5 ± 21.47  14.7 ± 4.29  4.92 ± 1.15  (±  6.9 6.4 5.8 19.1 ± 3.59  2.1 2.1 ± 1.88  Sj)  Shrubs  Gaultheria shallon Vaeeinium alaskaense Vaccinium parvifolium  2.6 4.7  Sum of shrubs (± s-)  7.3 ± 0.93  0.2 6.7 9.0 15.9 ± 1.37  1.4 0.1 1.0  162.0 24.8 15.9  65.3 5.8 7.3  2.5 ± 0.24  202.7 ± 12.18  78.4 + 4.20  Forbs  Chimaphila umbellate. Cormus canadensis Aohlys triphylla  0.1  0.6  -  3.0  0.1  2.6  -  -  -  -  Ferns  Blechnum spiaant TOTAL  86.53  31.2  7.43  224.8  80.63  31  occurred on low- and raid-elevation sites, respectively.  In one instance  where total weight of forage on a low-elevation site was greater than on a raid-elevation site, 88 percent of the total weight consisted of T. heterophylla foliage.  However, throughout the study area plants of T.  heterophylla in the understory showed l i t t l e evidence of being fed upon by deer.  Other studies dealing with black-tailed deer forage include  the work of Brown (1961) who measured air-dry weights of major winter forage species at 34 kg*ha  1  in mature and second-growth conifer stands  in western Washington. Gates (1968) reported green weights of 480 kg-ha"  1  of winter forage in mature stands of P. menziesii in central Vancouver Island.  Of this total, 97 percent was G. shallon with an average mois-  ture content of 58.5 percent.  These values represent an oven-dry weight  of approximately 200 kg G. shallon ha . 1  The quantities of forage in timber stands reported by Gates and Brown do not differ greatly from those reported in this study. Collectively these studies indicate average  weights  from approximately 7-225 kg-ha  1  of  winter forage available in mid- to low-elevation mature timber stands in coastal Washington and British Columbia.  In comparison,  quantities of winter forage (d.w.) available in 10- to  20-year-old cutovers or burns near their peak levels of production, in the absence of snow, have been reported as follows: 197 kg'ha  1  by Brown  (1961), 193 kg-ha" by Gates (1968), and 290 kg-ha" by Crouch (1964) in 1  1  Hines (1973).  Quantitative data on forage production in coastal forests are limited to these few studies which represent a limited number of study sites.  Con-  32  sidering these limitations, the data do suggest that quantities of rooted forage potentially available i n some timbered areas are not greatly different from quantities in cutovers. chapter, the greater  As w i l l be discussed later in this  snow depths which occur in cutovers compared to  timbered areas may act to further reduce this difference.  AMOUNTS AND NATURE OF FORAGE LITTERFALL  Because l i t t e r traps were in place for varying lengths of time on different  sites, l i t t e r  weights are calculated on a daily basis.  weights of l i t t e r f a l l kg'ha •'••day  1  ranged from 0.25 kg*ha day l4  on site 5 (Table 2-5).  of 0.93 kg'ha *'day 0.30 kg'ha •'••day  1  1  1  Oven-dry  on site 4 to 1.0  On mid-elevation sites an average  of forage l i t t e r f e l l compared to an average of  on low-elevation  sites (1, 3 and 4).  On a l l sites  lichens constituted the bulk of forage l i t t e r f a l l , making up 89, 86, 72, 90 and 92 percent of the total on sites 1-5, respectively.  Among lichens, Alectoria sarmentosa and associated Bryoria species made up the majority  Of lichen l i t t e r f a l l  on mid-elevation sites.  On low-  elevation sites 1 and 3, Lobaria oregana was the most abundant lichen in litterfall.  The combined group of Platismatia herrei, P. lacunosa and  Hypogymnion enteromorpha f e l l in greatest quantities on site 4.  Assuming a l i t t e r f a l l period of 180 days (October-April)  and the daily  rates of lichen f a l l noted above, computed amounts of 149 and 47 kg'ha  1  of lichens would be potentially available to deer in mid- and lowelevation stands, respectively.  These values exceed total amounts of  Table 2-5.  Components o f l i t t e r f a l l s u i t a b l e as deer forage (kg'ha" ). 1  Low e l e v a t i o n (Site): ( L i t t e r C o l l e c t i o n Period - days): Total  1  3  168  146  kg-' " i . d y "  1  Total  kg-  Mid-elevation 4  2  124 1 ,  dy  1  Total  5  169  kg-' - i . d y - i  Total  87  kg-' - i - d y "  1  Total  kg-' - l - d y - l  LICHENS: A l e c t o r i a spp.  1.9  0..01  10.7  0.07  9.8  0..08  108.3  Lobaria oregana  29.0  0..17  26.6  0.20  3.9  .0..03  P l a t i s m a t i a spp.  7.1  0..04  5.8  0.04  13.7  0.19  0..01  2.4  0.02  38.2  0..23  45.5  Tsuga h e t e r o p h y l l a  3.7  0..02  Thuja p l i c a t a  0.6  Pseudotsuga m e n z i e s i i Abies a m a b i l i s  0,.6  36.1  0,.4  2.1  0..01  27.4  0..3  0..11  14.9  0,.09  13.9  0..2  0.5  0..004  0.1  1.2  o..01  0.33  27.9  0..22  125.4  0..74  78.6  0..91  6..7  0,.05  1.7  0.01  15.4  0,.08  3,.8  0,.04  0..004  0..2  0..01  1.1  0.01  4.5  0..03  2..5  0..03  0.03  0..0001  11..2  0..08  0.3  0.002  1.1  0..006  0..4  0..005  0.2  0..001  4.5  0..03  18..1  42.7  0..25  63..6  Hypogymnion enteromorpha Sphaeroghorus globosus T o t a l Lichens  0..0005  GREEN CONIFER FOLIAGE:  Total Conifer  Foliage  TOTAL Lichens and C o n i f e r s  -  -  -  0..14  3.1  0.02  21.0  0..12  6..7  0..08  0..40  31.1  0.25  146.4  0..86  85..3  1..0  34  rooted forage available during the same period on four of the five sites studied.  Comparable values from other studies include Edwards et a l .  (1960), who  reported 82 kg'ha  of lichens made available through mor-  1  tality and windfall of trees plus an additional 21 kg'ha f a l l of individual lichens, for a total of 103 kg'ha . 1  made estimates of annual lichen l i t t e r f a l l kg'ha . 1  1  through the  Schroeder (1974)  in the range of 8 to  274  Denison (1972) estimated f a l l of Lobaria oregana in old-growth  Douglas-fir stands at 90 kg'ha  1  annually.  in several different forest types.  These values were determined  However, amounts of lichen l i t t e r f a l l  are reasonably similar among a l l studies including the present one.  The  present  study  did not define the reasons why  greater amounts of  lichen occurred in l i t t e r f a l l at mid- than at low-elevations. However, Stevenson (1978) determined that Alectoria sarmentosa was most abundant in stands at elevations greater than 500 m. reported that light  is one  Ahti and Hepburn (1967)  of the most c r i t i c a l factors controlling  abundance of arboreal macrolichens  such as Alectoria spp.  As a result,  highest densities of arboreal lichens are found around forest edges or around openings in the tree canopy.  As discussed earlier, measured overstory canopy coverages did not differ between low- and mid-elevation stands.  However, i t is likely that the  mid-elevation timber stands received greater amounts of light within and beneath the canopy.  Both mid-elevation stands occurred on south-facing  aspects and on steep (55 percent) slopes. aspects aspects.  At northern latitudes south  would receive greater total amounts of insolation than other The steep slope results in a greater proportion of the upper  35  tree crowns being exposed to f u l l sunlight for a longer period of time than occurs on more level ground or on other aspects. These same factors probably contributed to the greater growth of shrubs on mid-elevation sites.  Tree densities were greater and tree heights and diameters less  in mid-elevation than on low-elevation stands.  This could provide for a  greater area of and more variable sites for lichen attachment, thus influencing biomass of lichens present.  Other factors discussed by Ahti  and Hepburn (1967) as important to lichen growth include age of the tree hosts, nature of the bark substrate, and humidity.  Those factors were  not assessed in this study.  Conifer foliage suitable as forage occurred in l i t t e r f a l l ranging from 0.02 3  (Table 5).  kg-ha day 1,  1  on site 4 to 0.14 kg-ha -day 1  in amounts 1  on site  Calculated for a 180-day winter period, mid-elevation  stands produced a mean of 18.0 and low-elevation stands a mean of 11.4 kg-ha . 1  Tsuga heterophylla foliage occurred in greatest amounts, making  up 50 percent of total conifer foliage on a l l sites combined. This observation is expected as T. heterophylla made up an average of 60 percent of  stand composition on the five sites.  Conifer foliage contributed an  average of 14 percent of forage l i t t e r f a l l on the five sites; lichens made up the remaining 86 percent.  No other published studies were found which provided indications of the amount of conifer foliage l i t t e r f a l l which could serve as forage.  Grier  and Logan (1977) measured "green l i t t e r " weights of 5 to 50 kg-ha **yr in mature conifer stands in western Oregon (Table 1).  1  36  With regard to total biomass of foliage present, Turner and Cole (personal communication, 1975) summarized the literature on P. menziesii stands and noted a mean needle biomass of about 10,000 kg'ha 75-year-old stands.  Pike et al. (1972) estimated 5040 kg*ha  1  1  in 28- to of foliage  biomass in stands they studied. Values for the stands examined in the present study probably approximate these measures. specific biomass measurements i t appears foliage,  In the absence of  that minor amounts of green  suitable as forage, reach the ground as l i t t e r .  Assuming a  foliage biomass of 7500 kg*ha , less than 15 kg, or 0.2 percent f e l l 1  during a 180-day period.  In  summary, results  of l i t t e r f a l l measurements indicate that lichens  contribute the bulk of forage l i t t e r f a l l and in some forest stands provide a larger potential source of forage than understory vegetation. Green conifer foliage made up less than 15 percent of forage l i t t e r f a l l . Quantities of forage measured in mid-elevation stands approach the winter levels of forage production reported in the literature for cutover areas in similar forest types.  CONSUMPTION OF LITTERFALL BY DEER  To obtain information on the amounts of l i t t e r consumed by deer, fences 1.8 m high constructed of poultry netting were erected around 10 of the 25 l i t t e r  collection plots on sites 1 and 3. Among potential forage  items, general observations in the study area showed evidence of deer feeding on fallen Alectoria spp. spp. that accumulated  Table 2-6 l i s t s quantities of Alectoria  on fenced and unfenced plots during the winter  T a b l e 2-6. Amounts of Alectovia spp. l i t t e r f a l l t h a t accumulated on fenced and unfenced p l o t s d u r i n g the w i n t e r (x ± s g.m ) 2  x  Site 1  Site 3  Fenced p l o t s  0.38  ± 0.15  2.08  ±  1.17  Unfenced p l o t s  0.07  ± 0.03  0.40  ±  0.15*  *Denotes a s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e ^between fenced and unfenced p l o t s a t p < 0.05  38  collection period.  Over winter, fenced plots on both sites accumulated  about five times as much Alectoria spp. l i t t e r as unfenced plots.  This  difference, which was significant (p = < 0.05) only on site 3, suggested that deer are consuming substantial amounts of Alectoria l i t t e r .  Steven-  son (1978) also recorded significantly more Alectoria l i t t e r inside than outside deer exclosures.  The fences were not 100 percent effective in  excluding deer, particularly during the rutting period in November so that  some level of l i t t e r f a l l consumption inside exclosures probably  occurred.  It i s evident from rumen content analyses that at least the lichen component of l i t t e r f a l l is utilized as forage by black-tailed deer in winter. Alectoria spp. occurred at 100 percent frequency in rumens of 12 deer collected i n mature conifer stands.  These lichens made up 35.5 percent  of the volume of rumen contents of these deer.  Trace amounts of Alec-  toria spp. occurred in 33 percent of 24 deer sampled in cutover areas i n winter.  Foliage of conifers also occurred in significant volumes in  deer from mature forests but the source of this foliage could not be determined. larly  Heavy feeding was observed on fallen green limbs, particu-  of Thuja  plicata.  Observations  on food habits are discussed  further in Chapter III.  RELATIVE AVAILABILITY OF LICHENS AND UNDERSTORY VEGETATION  Heights of individual forage species in the absence of snow are listed in Table 2-7.  These values are mean heights for each species for the  entire site, weighted according to the frequency with which each species  T a b l e 2-7. Mean h e i g h t s o f a v a i l a b l e f o r a g e p l a n t s on the study 3  Site  s i t e s (cm).  Number Mid-elevation  Low-elevation Species Tsuga  heterophylla  Thuja Tsuga  plicata mevtensiana  2  4  3  1  15.24  5 20.12  A5.72  20.42  21.03  -  15.24  15.24  106.70  -  -  -  -  45.72  -  Gaultheria  shallon  -  15.24  15.24  20.42  26.52  Vaccinium  alaskaense  30.48  33.53  15.24  36.88  19.51  20.12  29.87  15.24  34.44  24.99-  22.86 ± 2.68  16.40 ± 1 . 4 7  43.23 ± 2.08  22.79 ± 1.84  Vaccinium  parvifolium  Mean h e i g h t o f a l l f o r a g e s p e c i e s (± s-)  32.11  ± 3.75  P l a n t s 137 cm o r l e s s i n h e i g h t , assuming t h e snow pack would not support a l l o w f e e d i n g on t a l l e r p l a n t s .  the weight of a deer and  40  occurred.  Assuming the snowpack would not support the weight of a deer,  only those plants considered available to deer, i.e. below 137 cm in height, were classified.  Snow depths as measured at each site at the  time of each monthly v i s i t are given in Figure 2-2.  Maximum snow depth  occurred in March, 1974 on three of the five sites.  Estimates made in  adjacent cutover areas revealed a snow depth of about twice that observed in timber stands. tude. 0.9  Jones (1975) observed differences of the same magni-  During the severe winter of 1971-72 he measured snow depths of  m and 1.5 m in timbered and cutover areas, respectively, at  610-m  elevation.  Figure 2-2 depicts the effect of snow depth during the winter on availability of rooted forage plants. Snow depths did not exceed mean heights of forage plants at any of the measurement dates on low-elevation sites. On mid-elevation sites snow depths exceeded or were only slightly below mean plant heights at most monthly measurement dates.  However, the data  in Figure 2-2 indicate that although snow depths may have exceeded forage plant heights on mid-elevation sites at the time of most monthly measurements, fluctuations in snow depth occurred  from month to month.  A  general increasing trend in snow depths throughout the winter did not occur at these elevations. Rather, the pattern was one of substantial snow accumulation December and  in November followed by reductions in snow pack in  January, and  subsequent build-up of the  snow pack in  February to maximum depth in March. In the winter of 1973-74, FebruaryMarch was the only period during which forage availability was  substan-  t i a l l y reduced at mid-elevations for an extended period of time.  This  winter was considered to be intermediate in severity from the standpoint  Low-elevation Mid-elevatIon  Sites  40  Site 2  40 J  Sites  "-*  0  Plant h t  30-1  a  30 P l a n t ht (cm)  3<M 20-  snow 20 depth (cm)  20  10-1  10-  hio ~l  Oct  ^  Nov  T"  U. f  T  "  Dec Jan Feb  "T—  1  T'  Oct  Nov  40 H  Mar Apr  1  1  T-  1  r  Dec Jan Feb Mar Apr  Site 3  -40 .30 P l a n t ht (cm)  30 Site 5  40  -i  L-20  10 -  10  20 30 -4  ,Plant h t (cm)  snow 20 depth (cm)  T  Oct  . 10  i  r  i  Oct  Nov  Dec  n T  40 -  Nov  a  T Dec  !  XL XL "r  T .  Jan Feb Mar Apr  Site 4  H40  1~-—TT—  Jan Feb Mar Apr  Figure 2-2. Snow depths r e l a t i v e to p l a n t height d u r i n g the w i n t e r o f 1973-74 mean height of combined forage p l a n t s  30.  h30 20 P l a n t ht (cm)  2010  1  'study s i t e not e s t a b l i s h e d .  JD  Oct  Nov  Dec  •n  Jan Feb Mar Apr  42  of  snow depth.  In a more severe winter, such as occurred in 1971-72,  substantially greater snow depths occurred and persisted throughout most of the winter period.  Although measurements were not made at elevations above 760 m, general observations indicated high snow levels and limited deer use of both timber and cutover areas.  Harestad  (1979) observed limited deer use at  elevations greater than 760 m in the same general area.  Jones (1975)  noted a significant increase in snow depths with elevation during the two  winters  of his study.  These observations suggest  that during a  severe winter with high snowfall, areas greater than 900-1000 m in elevation would be of limited value as deer habitat. Possible exceptions may be in areas of high crown closure, with steep slopes or with exposed rock bluffs.  Monthly rates of l i t t e r deposition on the study sites are illustrated in Figure 2-3 along with snow depths.  Total l i t t e r f a l l did not appear to  be closely related to snow depth as measured once a month. If a continuous record of snowfall had been made, a closer relationship might have been apparent. litterfall  An additional factor which obscures the snowfall-  relationship is that snow melt often occurred between meas-  urements of snow depth. period February  Greatest  forage  litterfall  occurred  i n the  to March; the result of portions of a dead tree top  bearing a large lichen load falling on site 2 (Figure 2-3).  The period  February-March was also the time of greatest snow depths during the winter (Table 2-6), and weight of snow was probably responsible for the breakage of the dead top.  It seems likely that l i t t e r f a l l was influenced  Litterfall (kg-ha^.dy )  Mid-elevation  Sites  litterfall,  - 1  Site 2  5 -  Litterfall 5 (kg-ha^-dy )  , ,<?  Mid-elevation  Site 1  Sites  50  -1  AO  - 50  snow A  -  3 —  AO  depth  30  j o  30  snow (cm)  20  2 1  3  Nov  r  Dec  n—i  Jan  5  10 T*"—i—' I " i Oct Nov Dec Jan  Feb Mar  f Feb  1  r—-r Mar Apr  _ 1  Apr  50  5  Site 3  L.  A  Litterfall (kg-ha~ .dy ) 1  1  Litterfall (kg-ha~ .dy ) 1  1  20  10  -er-  T Oct  2  depth (cm)  AO snow  _ 1  3  50  Site 5  4 -  AO  o t  snow depth 30 (cm)  \  3 -  I- 20  2 ~  10  "i  1  Oct  Nov  T " — r Dec  Jan  -r Feb Mar  2  H  1  1  Litterfall (kg-ha~ .dy" ) 5 1  1  - 30 - 20 -10  -i  1  Oct  Nov  1  I — "  Dec  r  J a n Feb  r  1 Mar  Apr  1  L 50  A-  h  3-  snow depth I-. 30 (cm)  Apr  Figure2-3. Monthly forage l i t t e r f a l l r a t e s and snow depth p a t t e r n s d u r i n g the s t u d y p e r i o d .  depth (cm)  2_  AO  f- 20  1-  10  —i—i—r*n Oct Nov  Dec  i T  —  J a n Feb Mar  T  Apr  44  most by snow and wind associated with individual storms, however, the design of this study did not permit examination of that relationship.  Comparison of amounts of understory vegetation and l i t t e r f a l l as potent i a l sources of forage for black-tailed deer in the study area during winter indicates that l i t t e r f a l l may provide the larger and more dependable forage supply. Forage l i t t e r f a l l amounted to 168 and 54 kg'ha mid-  and  low-elevation sites,  respectively  over  1  on  the 180-day winter  period.  Comparable values for rooted forage plants are 153  kg'ha .  In a winter with deep snow, rooted forage would be largely  1  unavailable.  and  42  Availability of l i t t e r f a l l would also be reduced, but to a  lesser extent as i t is deposited over the entire winter period and provides a continuing source of forage.  The  combined amounts of understory and l i t t e r f a l l  forage potentially  available to deer in timber stands observed in this study average 96 and 321 kg'ha , respectively on low- and mid-elevation sites. 1  The quanti-  ties measured on mid-elevation sites exceed the values of 193 to 290 kg'ha  1  understory forage measured in winter by Brown (1961), Crouch  (1964, in Hines 1973) and Gates (1968) in cutover areas at or near maximum stage of production.  In summary, the relative availability of l i t t e r f a l l and understory vegetation in some stands of mature conifers in winter approaches that measured for understory plants in winter in cutover areas in similar forest types.  Snow accumulation patterns during the winter of 1973-74 resulted  in both l i t t e r f a l l and rooted vegetation being intermittently exposed and  45  available to deer.  Snow depths in stands of mature conifers were about  half those observed In cutover areas; resulting in greater ease of deer movement in the conifer stands.  Rates of forage l i t t e r f a l l deposition  generally showed l i t t l e monthly variation and indicate l i t t e r f a l l provides a continuing source of forage.  SUMMARY  Results of this portion of the study provide some preliminary indications of the role mature conifer stands play as winter feeding areas for black-tailed  deer.  Variations in forage availability associated with  characteristics of timber stands were observed i n regard to both understory vegetation and l i t t e r f a l l . relatively  Observations made are pertinent to the  "mild" winter of 1973-74 but also provide information on  expected foraging conditions for deer during more or less severe winters. These include:  1)  Tree heights and diameters varied with elevation, resulting in substantially  lower  wood volumes  (665  m ha ) 3,  1  in stands  studied above elevations of 450 m compared to low-elevation stands (1700 m 'ha ). 3  2)  _1  Amounts of forage potentially available in l i t t e r f a l l in some mature conifer stands exceed amounts available in understory vegetation.  3)  Combined amounts of l i t t e r f a l l and rooted forage measured in mid-elevation timber stands in winter exceed amounts reported  46  for cutover areas at peak levels of forage production in winter in other studies i n western North America.  4)  Mid-elevation timber stands produced more than twice as much forage l i t t e r f a l l and contained over three times as much understory forage as the low-elevation stands that were studied.  5)  Lichens, primarily Alectoria spp., made up 86 percent of forage litterfall;  green  conifer  foliage  contributed very  forage relative to foliage available.  little  No instances of blow  down of live trees occurred on the study sites, suggesting that this would be a random and unreliable forage source.  6)  Snow deposition rates as measured in the study could not be related to rates of l i t t e r f a l l .  7)  During winter, snow melt made understory plants intermittently available to deer.  8)  Rumen analyses of deer  collected i n timber stands indicate  Alectoria spp., the major component of forage l i t t e r f a l l , is a major dietary item.  In  light of the reduced snow depths and levels of forage availability  observed in timber stands compared to cutover areas, timber stands are probably of greater value to deer during deep snow periods. This observation  is supported by previous research results  levels of winter deer use of mature conifer stands.  indicating high  47  LITERATURE CITED Abee, A. and D. Lavender. 1972. Nutrient cycling in throughfall and l i t t e r f a l l in 450-year-old Douglas-fir stands, pp. 133-143. In: Proceedings - Research on Coniferous Forest Ecosystems - A Symposium. Bellingham, Washington. March 23-24, 1972. p. 133-143. Ahti, T. and R.L. Hepburn. 1967. Preliminary studies on woodland caribou range, especially on lichen stands in Ontario. Research Report (Wildl i f e ) No. 74. Ontario Dept. of Lands and Forests. 134 pp. Bergerud, A.T. 1972. Food habits of Newfoundland caribou. Manage. 35: 913-923.  J. Wildl.  Boehm, W. 1972. Lichen occurrence in old-growth Douglas-fir, Ross Lake Basin. 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Thesis  Hines, W.W. 1973. Black-tailed deer populations and Douglas-fir reforestation in the Tillamook Burn, Oregon. Game Res. Rept. No. 3., Res. Division, Oregon State Game Commission. 59 pp. Hurd, R.M. 1971. Annual tree-litter production by successional forest stands, Juneau, Alaska. Ecology 52: 881-884. Jones, G.W. 1975. Aspects of the winter ecology of black-tailed deer (Odocoileus hemionus columbianus [Richardson]) on northern Vancouver Island. M.S. Thesis, Faculty of Forestry, "Univ. of British Columbia. 79 pp. Kufeld, R.C. 1973. 26: 106-113.  Foods eaten by the Rocky Mountain elk.  J. Range Mgmt.  Kufeld, R.C, O.C. Wallmo and C. Feddema. 1973. "Foods of the Rocky Mounta mule deer. USDA Forest Service, Research Paper RM-111. 31 pp. Lemmon, Paul E. 1957. A new instrument for measuring forest overstory density. J. Forestry. 55: 667-668.  49  Long, J.N. and J. Turner. 1975. Aboveground biomass of understory and overstory in an age sequence of four Douglas-fir stands. J. Appl. Ecol. 12: 179-188. Moir, W.H. 1972. Litter, foliage, branch and stem production in contrasting lodgepole pine habitats of the Colorado Front Range, pp. 189-198 In: Proceedings - Research on Coniferous Forest Ecosystems - A Symposium. Bellingham, Washington, March 23-24, 1972. pp. 189-198. Pike, L.H. 1971. The role of epiphytic lichens and mosses in production and nutrient cycling of an oak forest. Ph.D. Thesis, Univ. of Oregon, Eugene. 172 pp. Pike, L.H., D.M. Tracy, M.A. Sherwood and D. Neilsen. 1972. Estimates of biomass and fixed nitrogen of epiphytes from old-growth Douglas-fir. pp. 177-187. In: Proceedings - Research on Coniferous Forest Ecosystems - A Symposium. Bellingham, Washington, March 23-24, 1972. pp. 177-187. Rickard, W.H. 1975. L i t t e r f a l l in a Douglas-fir forest near the Trojan Nuclear Power Station, Oregon. N.W. Sci. 49: 183-189. Schroeder, G.J. 1974. Arboreal lichens: A discussion of their importance in the management of the Selkirk caribou. A report to the International Caribou Study Steering Committee. Mimeo. 12 pp. Scotter, G.W. 1971. Fire, vegetation, soil and barren-ground caribou relations in northern Canada. In: Proceedings - Fire in the Northern Environment - A Symposium. College (Fairbanks) Alaska - April 13-14, 1971. Stevens, D.R. Montana.  1970. Winter ecology of moose in the Gallatin Mountains, J. Wildl. Manage. 34: 37-46.  Stevenson, S.K. 1978. Distribution and abundance of arboreal lichens and their use as forage by black-tailed deer. M.S. Thesis. Faculty of Forestry, Univ. of British Columbia. 148 pp. Tarrant, R.F., Isaac, L.A., and R.F. Chandler, Jr. 1951. Observations on the l i t t e r f a l l and foliage nutrient content of some Pacific Northwest tree species. J. For. 49: 914-915. Telfer, E.S. 1970. Winter habitat selection by moose and white-tailed deer. J. Wildl. Manage. 34: 553-559. Will, G.M. 1959. Nutrient return in l i t t e r and rainfall under some exotic conifer stands in New Zealand. N.Z. J. Agric. Res. 2: 719-734.  50  CHAPTER III - FOOD HABITS OF BLACK-TAILED DEER, CHARACTERISTICS OF FORAGE PLANTS, AND RUMEN CHARACTERISTICS  ABSTRACT  Deer were opportunistic feeders utilizing forages as they became available; major shifts in food habits coincided with phenological changes in plants.  Shrubs and forbs were of equal importance in the annual diet;  lichens and conifers were important winter foods. Forbs were the largest dietary component in deer from cutover areas; shrubs, lichens and conifers were most prevalent in diets of deer from forested areas. Patterns of change i n forage characteristics of DDM, protein and fibre components were closely  related  to phenological changes.  Lichens were the most  digestible forage but contained less than 2 percent protein.  The 7 per-  cent protein requirement for maintenance i n deer was met i n ferns, forbs and shrubs during most of the year; conifers were below this level except at bud burst. Higher levels of nutrients were not consistently apparent in plants from  cutover compared to forested areas in part because of  phenological differences.  DDM of forage species.was  when they were part of forage mixtures.  generally enhanced  Presence of Alectoria sarmentosa  appeared to enhance the DDM of the overall diet.  Crude protein and dry  matter levels of rumen contents paralleled those of forage species and reflected seasonal changes in food habits.  51  CHAPTER III - FOOD HABITS OF BLACK-TAILED DEER, CHARACTERISTICS OF FORAGE PLANTS, AND RUMEN CHARACTERISTICS  RATIONALE AND OBJECTIVES  This chapter treats the related areas of food habits, forage characteristics and characteristics of rumen contents.  The rationale for treating  each of these areas and the associated objectives follow.  FOOD HABITS  Rumen analyses provide data on food habits which reveal the seasonal patterns of consumption of forage species and reflect forage preferences and availability.  They supplement field observations of forage use as  indirectly indicated by browsed plants in varied habitat types. Knowledge of the composition of diets provides the basis for selection of plants for assessment of their nutritive value to the herbivore.  The objectives of the analyses of deer food habits made in this study were:  1)  To estimate monthly and seasonal patterns of use of individual forage species,  2)  To estimate potential differences in forage use between forested and cutover areas,  3)  To estimate patterns of forage use relative to plant phenology.  52  CHARACTERISTICS OF FORAGE PLANTS  The nutritive value of forage plants varies widely with both species and stage of growth. Selection of food by deer and other ruminants i s related to the nutritive quality of the forage plant (Swift 1948, Weir and Torrell 1959,  Longhurst et a l . 1968).  Chemical  composition and associated d i -  gestibility of plants determine the degree to which nutritional requirements of deer are met. Coupled with information on forage availability, information on forage quality provides a measure of carrying capacity of deer range (Wallmo et a l . 1977, Dietz 1972).  My objectives in examining forage characteristics were:  1)  To determine patterns of seasonal variation in chemical characteristics of forage species,  2)  To compare selected characteristics of forage to determine their relative values as nutritional indicators for use in assessments of deer range,  3)  To determine  the combined  digestibility  of forage mixtures  relative to digestibility of the individual component species, 4)  To determine  i f differences in nutritive value occur in the  same species growing beneath mature forest compared to cutover areas, 5)  To assess the value of individual forage species in meeting the nutritional requirements of deer.  53  RUMEN CHARACTERISTICS  Variations of crude protein levels of rumen contents reflect combined protein levels of dietary components and of rumen microbes.  Weight of  rumen contents as a proportion of body weight increases to some point as diet  quality  matter  is reduced  and then becomes constant or decreases.  of rumen contents can reflect  the moisture  Dry  content of forage  plants, which in turn influences their nutritive value.  The objective of measuring characteristics of the rumens from deer collected in this study was to examine changes in rumen f i l l , moisture and crude protein content as these were related to changing nutritive values of forage plants.  FOOD HABITS OF BLACK-TAILED DEER  LITERATURE REVIEW  A knowledge of food habits indicates seasonal patterns of food selection and is fundamental to understanding the animal's relations with i t s environment. Analyses of rumen contents provide a relative measure of forage preference.  Information on availability is necessary to make quantitative  estimates.  This technique was employed by others working with black-  tailed deer on Vancouver Island (Cowan 1945, Gates 1968, Jones 1975) and their findings indicate the most important forage species in the region.  54  A limitation associated with analysis of rumen contents is the different i a l digestibility which occurs among plant species, and which can result in  overestimation  of  those  (Bergerud and Russell 1964).  indigestible  or  slowly-digestible plants  The same limitation applies to analysis of  fecal pellets (Anthony and Smith 1974).  The need to sacrifice animals  can be a limitation with rumen content analysis, but was not in this study because needs for rumen inoculum  and other kinds of body measurements  also required sacrifice of deer.  Cowan (1945) documented year-round southern Vancouver Island.  food habits of black-tailed deer on  Gates (1968) determined  food preferences of  deer during f a l l , winter and the spring-summer transition period for the Northwest Bay area in Central Vancouver Island. A comprehensive evaluation of deer food habits in western Washington was made by Brown (1961).  In the Nimpkish Valley of northern Vancouver Island, where this study was conducted, Jones (1975) determined food habits of black-tailed deer during both a mild and a severe winter.  During the severe winter, which had  extended periods of deep snow, only conifers, shrubs and lichens occurred in more than 50 percent of the rumen samples.  In the mild winter, ferns  and forbs also occurred in more than 50 percent of the samples, as did conifers, shrubs and lichens.  These findings reflected the greater avail-  ability of plants to deer under conditions of lower snow depth.  55  METHODS  Food Habits Determination  Seasonal variation in deer food habits was determined through analysis of rumen contents.  A minimum of two deer were sacrificed each month. An  additional 46 rumens were obtained from hunter- and road-killed deer and from deer collected to evaluate potential differences between forested and cutover areas.  Distance from cutovers, high snow depth in cutovers  and absence of deer tracks indicating movement into cutover areas were criteria used to provide reasonable assurance that deer had been confined to forested areas one or more days prior to collection.  Cutover areas  had been logged 1-20 years earlier; forested areas were-mature conifer stands.  A sample of approximately 1000 ml was taken from each rumen. This consisted of several subsamples from different locations within the rumen. Samples were preserved in 10 percent formalin solution until detailed analyses  could be conducted.  Lab analyses were done by the British  Columbia Fish and Wildlife Branch, Wildlife Research  lab in Victoria.  Frequency of occurrence and percent of total rumen content volume were determined for each forage species.  Information on food habits was collected monthly over a one-year period. The number of rumens analyzed and their area of collection (e.g. forested area or cutover), varied in response to collection schedules for other data needs, road k i l l patterns, and hunting season dates.  56  Seasons of collection were defined based on the phenological stage of forage plants as follows:  spring, the period of growth initiation and  rapid early growth (May-June); summer, the period in which growth was completed  and  tissue  maturation  occurred  (July-September);  and  fall-  winter, the period during which leaf abcission occurred in deciduous species, lignification of woody tissues was completed and plants became dormant (October-April). Although other subdivisions of the year could have been selected, these seasonal groupings  seemed to reflect periods  within which plants were in similar physiological states.  Species were placed into five major plant types which represented the most important morphological forms known to be used as forage. were shrubs, conifers, lichens, forbs and ferns. minor types  were defined and  Types  In addition, several  included fungi, mosses and  liverworts,  grasses, deciduous trees, berries, twigs and bark and Equisetum.  Importance Value (IV) (Mealey 1975) is used as the measure of forage consumed.  IV is calculated from frequency of occurrence and volume of a  forage species or type in the rumen sample as follows:  IV - Frequency of Occurrence (percent) x Volume (percent)  IV ^percent; (percent) iv  =  j  I V  o f  I y  a  f o r a U  g  e  f Q r a g e  i t e m i t e m s  x  x inn lUU  Importance Value (percent) provides a measure of forage use for an item relative to the use of other forage items. quency  and  volume  of  occurrence,  Since i t combines both fre-  the potentially  misleading  values  resulting from an item occurring in high volume and low frequency, or the reverse, are more readily accommodated.  RESULTS AND DISCUSSION  Seasonal food habits of deer collected in forested and cutover areas, and the combined values for both areas are presented in Figure 3-1.  Values  presented are for major forage types or species, and include the 5 to 10 species with highest IVs which in combination made up 80 percent or more of the diet.  Volume and frequency of occurrence information is contained  in Appendix Tables 1, 2 and 3, which include data for a l l forage types and the 15 species occurring at highest frequencies.  The large contributions of forbs and shrubs to the spring and summer diet are readily apparent  (Figure 3-1). Forbs appear to be used in direct  relationship to their availability, as indicated by the reduction in their IV in the fall-winter diet.  Calculation of average  IV on a year-long  basis, done by weighting seasonal IVs relative to the number of months in a season, summing these values and dividing by 12, indicates of forage types in the annual diet.  importance  Average annual percent IV for forage  types are 35.5, 34.1, 11.0, 6.5 and 3.1 for forbs, shrubs, lichens, conifers and ferns, respectively.  Thus, although high seasonal variation in  use of forage types occurred, forbs and shrubs are of equal importance in the annual diet.  Forbs, particularly Epilobium angustifolium, were much more abundant in cutover than in forested areas, and this was reflected in rumen composition of deer taken from these areas (Figure 3-1). Conifers occurred in greatest quantities during spring and the' fall-winter season, but in substantial quantities only in rumens of deer from forested areas.  Lichens  SPRING  SUMMER  FALL-WINTER  2  n = 2  n = 11 Other 6.7 C o n i f e r s 12.3  FORESTED  Forbs 13.9 Ferns 8.0 C o n i f e r s 4.2 Other 3.6 n - 11  n = 18  Grass 8.6  n = 28  CUTOVER  Gras9 2.9 Liverwort-moss 6.5 n = 13  Berries 4 . 4 Other 4 . 5 n = 39  FORESTED AND CUTOVER  Other 3.9 Ferns 3.0  Importance v a l u e i s the product o f percent frequency Percent importance v a l u e i s the importance value the sum o f importance v a l u e s f o r a l l types. No samples were taken from deer i n f o r e s t e d areas i n F i g u r e 3-1. Seasonal importance v a l u e s (%) f o r forage i n f o r e s t e d and cutover areas. 2  C o n i f e r s 11.1  of occurrence and percent volume. of i n d i v i d u a l types d i v i d e d by summer. types consumed by b l a c k - t a i l e d deer Ln  oo  59  likewise were evident only in substantial quantities in rumen contents of deer  from  forested  areas, and  only in the fall-winter period.  Ferns  occurred at low levels in deer from forested areas in spring and  fall-  winter .  Monthly patterns of use of forage types are shown in Figure 3-2.  Details  of volume and frequency of occurrence are contained in Appendix Table 4. Conifers, lichens, ferns and shrubs make up the bulk of the diet during the late winter months.  Forbs are present in the diet in substantial  amounts in January and their use declines in February and March, probably in response to snow reducing their availability. Forbs used during winter are primarily perennial species which retain their (e.g.  leaves year-round  Cornus canadensis and Linnaea borealis).  April is a transition period between winter and spring relative to diet composition. in  spring  Equisetum April  Grasses, which are among the f i r s t plants to begin growth appear  in  substantial  quantities  in the  diet  in April.  spp. also initiate growth and contribute significantly to the  diet.  Germination  of annual  forbs and initiation of growth of  perennial forbs occur in April and this increased availability begins to become apparent by increased quantities in rumen samples. shrubs does not begin until May.  Growth of most  Forbs constitute the bulk of the diet  during the months of May to October, when dieback from frost reduces their availability.  New tissue of shrubs also contributes substantially to the  diet during this period.  In  late f a l l  and early winter, shrubs, conifers and lichens again in-  crease in IV along with perennial forbs.  Importance V a l u e  Jan (3)  (%)  Feb ' Mar (5) . '1 : (8) :  1  F i g u r e 3-2.  Monthly  Apr \ . May (6) • ; : (7)  Jun ' .; Jul ' (6) . (5) .  Aug ' (11)  p a t t e r n s of use of f o r a g e types by b l a c k - t a i l e d  Sep (2) \\  Oct (A)  .  Nov (9)  .  Dec (4)  deer' f o r f o r e s t e d and cutover areas combined.  61  Seasonal patterns of consumption of individual species are illustrated in Figure 3-3.  Data on frequency and volume of occurrence are contained in  Appendix Tables 5, 6, and 7.  Although a large number of species are  eaten, relatively few species make up a large proportion of the diet. During spring, Epilobium angustifolium is heavily used in cutover areas, while Rubus spp. contribute significantly to the diet in both forested and cutover areas. Cornus canadensis, a perennial forb, has a high IV in deer from cutovers, and Vaccinium spp. are present i n significant quantities in spring rumens of deer from both areas.  The summer diet in cutovers (no samples from forest in summer) differs little  from the spring diet with E. angustifolium constituting an even  larger share of the diet.  Shrubs are also important in summer, with  berries of Rubus spp. being eaten as they become available.  The fall-winter diet is more varied than the summer diet.  E. angusti-  folium continues to receive high levels of use in spite of reduced succulence and discoloration brought about by frost.  The use of deciduous  shrubs, Vaccinium and Rubus spp., declines, and use of the evergreen shrub Gaultheria shallon is increased. Thuja plicata receives relatively heavy use during fall-winter and the fern Blechnum spicant receives i t s greatest use at this time. are  important components of the fall-winter diet of deer from forested  areas. is  The lichens Alectoria sarmentosa and Lobaria oregana  This change in diet associated with leaf f a l l in deciduous shrubs  the basis for distinguishing between summer and f a l l at the end of  September.  LEGEND  SPRING Shrubs RUBUS = Rubue spp. RUBE = Rubus b e r r i e s VACC = Vaccinium spp. GASH = Gaultheria shallon Conifers THPL = Thuja plicata TSHE = Tsuga heterophylla  SUMMER n = 2  TITR COCA POPA LIBO Ferns BLSP PTAQ  n = 11  CUTOVER  RUBUS 49.5  EPAN \ 25.0  VS. Y  • n = 13  VACC 8.6  Grass  10.0  Other 10.4 COCA 3.7 THPL 4.8 LIBO 5.2 BLSP 5.5 EQUIS 10.0  = 39  -J-Other 8.9 zr-—COCA  28  her 8.6 LYAM 3.5 RUBE 4.2 VACC 6.3 RUBUS .11.  AND CUTOVER I  F i g u r e 3.3  n = 18  Other 6.3 Grass 3.3 •VACC 4.8 POPA 5.2  Blechnum spicant Pteridium FORESTED/ aqualinum  grass spp. Lysichitum americanum L.wort= l i v e r w o r t Fungi = Fungi EQUIS = Equisetufn spp.  Other 4.8 Fungi 2.9 L.wort 3.5 TSHE 4.0 THPL 5.9  PTAQ 5.3  Epilobium angustifolium Tiarella trifoliata Cornus canadensis Potentilla pdlustris Linnaea borealis  Other Grass LYAM  n = 11  Other 4.6 BLSP 3.3 EPAN 3.3 TITR 4.1 TSHE 4.5  FORESTED  Lichens ALS A Alectoria sarmentosa Forbs EPAN  FALL-WINTER  8.0  Other 11.0 Grass 3.3 EQUIS 3.3 BLSP 3.3 Fungi 3.1  THPL Importance value (IV) i s the product of percent frequency of occurrence and percent volume. Importance value (%) i s the IV of i n d i v i d u a l species d i v i d e d by the sum of IVs f o r a l l species.  Seasonal p a t t e r n s of use by b l a c k - t a i l e d deer of forage species i n forested and cutover areas.  63  These temporal trends are displayed in Figure 3-4 which indicates patterns of use of forage species on a monthly basis.  Details of frequency and  volume of occurrence are listed i n Appendix Tables 8, 9 and 10. The perennial forbs Cornus canadensis and Linnaea borealis are well represented i n the diet  i n the winter months.  Blechnum spicant and Thuja  plicata receive greatest use from January to March. T. plicata is also a substantial component of the diet in September. Alectoria sarmentosa is well represented in the diet during November, December, February, March and April.  Use of Gaultheria shallon is greatest in November, February  and March. During spring and summer months, Rubus and Vaccinium spp. are the most consumed shrubs.  SUMMARY - FOOD HABITS OF BLACK-TAILED DEER  Food preferences and apparent patterns of availability are jointly reflected in composition of rumen contents. Deer appeared to be opportunistic feeders, as indicated by their relatively high consumption of forage items such as shrub berries and fungi which were available for only short periods of time.  Cowan (1945) arrived at similar conclusions for southern  Vancouver Island.  Grasses and Equisetum spp. initiated growth earlier in  spring than most other plants and were important dietary components at that time (Figure 3-4). year-long  diet  Forbs and shrubs were of equal importance in the  as indicated  by annual  angustifolium clearly dominated  Importance Values.  Epilobium  spring and summer diets, and perennial  forbs (Cornus canadensis and Linnaea borealis) contributed significantly to diets at other times of the year. This observation is in contrast to the findings of Cowan (1945) who noted that on a year-round basis deer  64  Importance Value (%)  Fall-Winter  Spring  Summer  Fall-Winter  Alee tor-ia sarmentosc.  Epilobium angustifo  i  J (3)  F M 1  (5)  (8)  A (6)  r M J (7) (6)  J (5)  A (11)  S (2)  N (9)  D (4)  MONTH 1  Number of rumens analyzed.  F i g u r e 3-4.  Monthly p a t t e r n of use by b l a c k - t a i l e d deer of forage i n f o r e s t e d and cutover areas.  species  lium  65  were primarily browsers  making l i t t l e  use of low-growing vegetation.  Similarly, Brown (1961) observed that woody species constituted most of the annual diet of black-tailed deer in western Washington.  Results of  the present study indicate that forbs are equal in importance to woody vegetation.  The findings of Gates (1968) in central Vancouver Island are  similar to those of the present study and indicates forbs are important dietary components in spring and summer.  Conifers, particularly Thuja plicata, were important in the diet of deer in the Nimpkish Valley mainly in the winter (Figure 3-3).  Jones (1975)  also recorded high levels of use of Thuja plicata in winter in this area. High levels  of use of Pseudotsuga  menziesii, as observed on southern  Vancouver Island by Cowan (1945), did not occur in the Nimpkish Valley even though this species was highly available in plantations of various ages.  Tsuga heterophylla received moderate levels of use in fall-winter  in the study area and in western Washington (Brown 1961) but was not consumed in southern or central Vancouver Island (Cowan 1945, Gates 1968).  Lichens, primarily Alectoria  sarmentosa,  were important winter foods.  Snow and winds of winter were responsible for their availability at this time and they appeared to be a preferred forage of deer collected in forested  areas  (Figure  3-1).  Cowan (1945) also noted heavy use of  arboreal lichens in his study area, and ranked them as the second most important forage on an annual basis.  Gaultheria shallon was widely available to deer on a year-round basis but received heavy use only in winter, suggesting that i t is of low preference.  66  Reduced availability  of forage plants in winter was  reflected in the  smaller number of species which occurred in rumens of deer in winter, particularly  those  collected  in timbered  areas.  similar observation as did Jones (1975) who  Cowan (1945) made a  observed  fewer species in  rumens of deer in a severe winter compared to a mild one.  Phenological changes i n plants were reflected in changed food habits. Major dietary shifts occurred in conjunction with growth initiation in April and May  and again with frost and cessation of growth in October  (Figure 3-2).  FORAGE CHARACTERISTICS  LITERATURE REVIEW  Forage characteristics considered include dry matter, crude protein, dry matter digestibility and rates, and composition of forage fiber as measured by Van Soest feed analyses.  Dry Matter Content  Dry matter content i s nutritionally important mainly as i t reflects other changes occurring in the plant. With tissue maturation in woody plants, moisture content declines and the proportion of dry matter content therefore increases; lignin and cellulose concentrations increase and digestibility  declines (Short 1971).  Bissel et a l . (1955) discuss how  the  proportion of dry matter in a forage species is related to the availability of other nutrients.  67  Dry matter  content of shrubs  and  trees varies widely in relation to  phenology. Less variation occurs in forbs which, while they remain green, tend to be of lower dry matter content than woody plants.  Although levels of most nutrients tend to be highest in new-growth tissue, dry matter contents are low. highest at this time.  Dry matter digestibility of most plants is  However, because of the high moisture content,  greater food intake may be required for a level of nutrient intake equivalent to that which would occur later in the season.  Increased food intake  and improved digestibility are apparently the mechanisms through which overall nutrient intakes are maximized in spring and summer (Short 1963, Nagy et al. 1969).  Crude Protein  Protein is an essential nutrient for body maintenance and production and is involved in many physiological processes. both protein and  Crude protein consists of  non-protein nitrogen (Wood et a l . 1960).  Since the  ruminant can synthesize protein from other nitrogenous substances in the rumen, the level of dietary nitrogen is of more importance than levels of protein and amino acids (Dietz 1965).  Inadequate levels of dietary protein result in reduced growth rates in white-tailed deer (Qdocoileus virginianus) (Short 1969). Dietary protein levels of 6 to 7 percent and 7.8 to 12.7 percent are required for the maintenance of body weight of white-tailed deer adults (French et a l . 1955)  and fawns (Ullrey et a l . 1967), respectively.  Murphy and Coates  (1966) observed that does fed diets of 7 to 11 percent protein produced  68  fewer fawns than those on higher-protein d i e t s . suggested that d i e t s of 13 to 16 percent w h i t e - t a i l e d deer.  French et a_l. (1955)  r e s u l t i n optimum growth of  Dietz (1965) noted that when d i e t a r y p r o t e i n l e v e l s  f a l l below 6 to 7 percent, rumen function i s adversely a f f e c t e d .  Cowan et a l . (1970) observed that p r o t e i n l e v e l s are often r e l a t e d to l e v e l s of other n u t r i e n t s i n p l a n t s .  These i n v e s t i g a t o r s i n d i c a t e d that  for some combinations of n a t u r a l foods eaten by deer, i f an adequate percentage of crude p r o t e i n i s present, other n u t r i e n t requirements may i n c i d e n t a l l y covered.  be  That there are exceptions to t h i s pattern was shown  by B l a i r et a l . (1977) i n the Southeastern U.S. where twice as much forage was required to supply adequate phosphorus as was required to supply adequate p r o t e i n .  A s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n e x i s t s between crude p r o t e i n and d i g e s t i b l e p r o t e i n ( S u l l i v a n 1962) forage provides a reasonably  so that the crude p r o t e i n l e v e l of a  r e l i a b l e i n d i c a t o r of feed value.  I t should  be recognized that there may be exceptions, such as that noted above.  P r o t e i n l e v e l s may phenological  stage,  vary g r e a t l y between species and w i t h i n species with plant  portion  and  reviewed s o i l - p l a n t - n i t r o g e n r e l a t i o n s . protein  l e v e l s i n forage  plants  soil  fertility.  Einarsen  Dietz  (1972)  (1946) noted increased  eaten by b l a c k - t a i l e d deer on burned  s i t e s ; apparently the r e s u l t of nitrogen mobilized i n the f i r e becoming a v a i l a b l e to the p l a n t s .  High l e v e l s of p r o t e i n occur only when p l a n t  growth i s r a p i d (Short 1971). d i l u t e d by the  As  t i s s u e s mature, nitrogen content  rapid accumulation of carbohydrates,  is  some of which are  69  resistant to digestion.  As the cell wall hardens through lignification,  protein and other nutrients become less available to rumen microorganisms (Dietz 1972).  Significant seasonal declines in protein content of black-  tailed deer forage plants were observed between summer and late winter (Gates 1968).  Brown (1961) observed declines in protein content of most  important black-tailed deer forage species between January and February. Cowan et al. (1950) noted that levels of nutrients, including protein, in woody plants were lowest near the end of the dormant period.  Digestibility of Dry Matter  Digestibility of a forage indicates the degree to which i t can be altered chemically and physically by digestive processes to a state in which the nutrients i t contains are available for absorption and use i n the animal's metabolic processes (Skeen 1974).  In the case of deer and other rumi-  nants, carbohydrate digestion is largely accomplished by microorganisms (bacteria and protozoa) present in the rumen. Digestibility values are nutritive integrators in that they reflect the ability of the ruminant to digest a total  forage, as compared to the Weende system of proximate  analysis (Maynard and Loosli 1962) which partitions forage into types of nutrients but provides l i t t l e  indication of their availability to the  animal (Harlow and Whelan 1969, Dietz 1972).  The  in vitro digestibility technique involves fermentation of a known  amount of forage substrate in a mixture of rumen inoculum and " a r t i f i c i a l saliva" (McDougall 1948) or buffer solution.  Controlled conditions of  temperature and anaerobiosis are maintained for a specified time period,  70  normally 48 hours. With the Tilley and Terry (1963) two-stage technique, plant samples undergo a second 48-hour period of incubation in an acidpepsin  solution.  This  second stage simulates  the enzymatic digestion  which occurs in the small intestine.  The in vitro technique has greatly simplified the determination of forage digestibility  in comparison to the in vivo method which requires  animals, large samples and much time in collecting feces and urine.  live  and weighing feed,  A major advantage is that several forages can be simul-  taneously evaluated  in vitro with inoculum from a single animal.  Disad-  vantages include the need to sacrifice wild animals or fistulate domestic animals, and the possibility  that the ruminal environment will not be  accurately duplicated.  Results  of in vitro  digestibility trials correlate well with those ob-  tained from in vivo trials (Tilley and Terry 1963, Oh et a l . 1966, Johnson and Dehority 1968, a l.  Ruggiero and Whelan 1976). In addition, Baumgardt et  (1962) have shown that in vitro digestibility is highly correlated  with in vitro digestible energy and digestibility of forage protein.  Several  factors influence in vitro  digestibility  measurements through  their influence on rumen microbes responsible for carbohydrate digestion. Inoculum may  be  less viable when storage  periods  approach 2 hours  (Schwartz and Nagy 1972). Cooling or freezing of rumen inoculum decreases levels of volatile fatty acids (VFA), gas production  (Nagy et a l . 1962)  and digestibility (Pearson 1970). Previous diet of the animal used as an inoculum  source  can  also  affect in vitro  digestibilities.  Van Dyne  71  (1962), Bruggeman (1968) and Pearson (1970) found that digestion coefficients were higher when inoculum donors were fed the same forages as were being evaluated. This is usually not possible when wild deer are used as the inoculum source.  In contrast, Skeen (1974) noted that diet substrate  of donors did not significantly affect digestion of test diets.  FOrage evaluation for an animal species should be conducted with rumen inoculum for that species. same plants results.  with ihocula  Short (1963) found that digestibility of the from cattle and  deer rumens gave different  Nowlin (1974) noted differences in forage plant digestibility  in inoculum from elk and cattle.  However, Palmer et a l . (1976) found a  highly significant correlation between in vitro values for cows and in vivo values for deer.  Rates of Forage Digestibility  The  level of dry matter digestibility, based on a 48-hour fermentation  period and  a 48-hour digestion period in pepsin solution, provides an  indication of the potential value of a ruminant forage.  The rate at which  digestibility occurs greatly influences the degree to which the animal realizes this potential value.  Rumen retention time, or conversely, with their physical properties.  turnover rate, of feedstuffs varies  Mautz and Petrides  (1971) estimated a  rumen retention time of 14 to 19 hours for succulent (and presumably d i gestible) foods of white-tailed deer. For a more fibrous hay meal, Cowan et a l . (1970) estimated a rumen retention time of about 33 hours.  In-  72  creased  retention time  results  in reduced  food intake (Short 1971).  Forages that are slowly digested may leave the rumen prior to their being fully broken down. The caloric value of slowly-digested forages is not realized with the result that less net energy is provided to the ruminant.  Short (1975) estimated the number of times that rumen contents of deer would be turned over during a 24-hour period. He observed  significant  differences in turnover rate associated with the quality of the diet, with the most rapid turnover occurring during the spring-summer period when forage digestibilities were high.  In the same study, Short examined  rates of digestibility of holocellulose of selected mature forages. Rates varied  from 75 percent digested in 4 hours for leaves of  honeysuckle  (Lonicera japonica) to only 20 percent of a mixed sample of mature twigs digested in 24 hours.  Forage Fibre Analyses  A comprehensive system of feed analysis developed by Van Soest (1967) provides a chemical method of forage evaluation which eliminates the need for  rumen inoculum.  This system partitions plant components based on  their differential solubilities in neutral and acid detergents. Readilydigestible soluble  cell  contents  (simple  in neutral-detergent  sugars,  solution  (neutral-detergent fibre-NDF) are not. of  protein, starch, etc.) are  while  the  cell  wall  contents  Hemicellulose, a major component  the digestible portion of cell walls is soluble in acid detergent.  Thus, the difference between neutral-detergent and acid-detergent fibre is a measure of hemicellulose content (Van Soest and Wine 1967).  Both  73  lignin and cellulose are insoluble in acid detergent and make up the aciddetergent fibre (ALT).  Treatment of the ADF fraction with sulfuric acid  which dissolves cellulose, followed by ashing estimates the lignin fraction.  Lignin (L) is the most important factor limiting cell wall digesti-  b i l i t y (Goering and Van Soest 1970).  In summary, the Van Soest method of chemical solubility partitions forage according to i t s component digestibilities as follows:  1 - NDF = cell contents (98 percent digestible; Short and Reagor 1970) NDF = cell wall contents (including digestible hemicellulose) ADF = cell wall contents less hemicellulose = lignocellulose NDF - ADF = hemicellulose content ADL = lignin portion of ADF (indigestible, also contains cutin and acid-insoluble ash, mainly silica) ADF - ADL = cellulose content  Short and Reagor (1970) compared results of in vivo digestion trials with the Van Soest system of feed analysis.  They observed that deer digested  cell contents of woody twigs as well as domestic ruminants but that d i gestibility of cell wall contents of twigs was less than that of herbages. Short et a l . (1973) found that the summative equation to predict digestib i l i t y based on this method and the lignocellulose content (Van Soest 1967) correlated well with in vitro digestibility but that predictability declined as woody stem tissue matured.  The negative effect of lignin on  digestibility of woody tissues was illustrated by Short et a l . (1972)  74  with  Sassafras  digestibility  albidum  twigs.  Following chemical  removal of l i g n i n ,  increased from the normal 16 to 19 percent  to 75 to 79  percent.  In comparisons of laboratory techniques f o r p r e d i c t i n g i n vivo dry matter d i g e s t i b i l i t y , Oh et a l . (1966) found that among c e l l - w a l l c o n s t i t u e n t s , acid-detergent l i g n i n provided the best p r e d i c t o r of d i g e s t i b i l i t y w i t h i n forage  species  but that i n v i t r o  digestibility  of dry matter  superior p r e d i c t o r f o r a v a r i e t y of forage species and mixtures.  was a Robbins  et a l . (1975) s l i g h t l y modified the detergent procedures of Goering and Van Soest  (1970) and obtained acceptable estimates of i n v i v o dry matter  d i g e s t i b i l i t y of w h i t e - t a i l e d deer feed.  Results discussed above d i f f e r with respect to the c o r r e l a t i o n between detergent-fibre analyses and i n v i v o or i n v i t r o  observed  digestibility.  V a r i a t i o n probably r e s u l t s from the use of s l i g h t l y d i f f e r e n t procedures or the v a r i e d forages studied. This system of feed a n a l y s i s does provide a relatively the  relative  simple means of p a r t i t i o n i n g feeds and forages according to digestibilities  of t h e i r components.  In t h i s respect i t  overcomes several of the l i m i t a t i o n s associated with the proximate  analy-  s i s method of forage evaluation (Dietz 1972).  S o l u b i l i t y of Forage  The  proportion  (McDougall tent.  of a  forage  which  i s soluble  in artificial  saliva  1948) provides a measure of r e a d i l y - a v a i l a b l e n u t r i e n t con-  Pearson  (1970) observed  that s o l u b i l i t i e s  of forages  d i d not  75  correlate significantly with in vitro digestibility and concluded i t was of no value in predicting forage digestibility. (1975) determined the Tilley  Conversely, Uresk et aJL.  solubility of several species in various components of  and Terry (1963) in vitro system and observed  that Arcto-  staphylus uva-ursi incubated in a r t i f i c i a l saliva underwent a loss in dry matter equal to 85 percent of i t s in vitro digestibility.  They attributed  this high solubility to the species' high intra-cellular carbohydrate and mineral content and suggested this may help explain i t s importance as a winter browse species.  While there is limited research, and less than unanimous agreement as to the value of solubility measurements as forage quality indicators, this simple technique may have practical value in indicating levels of readilysoluble c e l l contents.  Solubility was examined in this study relative to  other forage quality parameters to further evaluate i t s potential as a forage quality indicator.  Digestibility (DDM) of Forage Mixtures  Knowledge of the relative values of individual species provides an index of that species' contribution to total nutrition of deer.  Such values  provide basic information needed to assess impacts of management activities which modify species composition and abundance in the habitat (Urness et a l . 1975).  Although data on individual species are useful and neces-  sary to understanding specific diets.  deer nutrition, wild deer  seldom consume mono-  Rather, a large number of species, often with widely-  differing nutritive characteristics are eaten.  76  Church (1969) pointed out that the species composition of rumen microbial populations changes with changing dietary composition causing subsequent changes in the end products of digestion. Pearson (1969) recorded significantly higher bacteria and ciliate protozoa populations in rumens of mule deer fed a 2-component diet (barley plus alfalfa) than in deer on single species diets  (bitterbrush, alfalfa  and  curlleaf  Cercocarpus).  Populations of each of the seven types of bacteria and two  protozoan  species present were higher in deer on the barley-alfalfa than on the other diets.  Increased numbers of microbes may be more directly related  to the presence of the barley, which is high in readily-available carbohydrates, than to the 2-component diet. habitat Pearson (1969) also noted  In deer feeding i n the natural  seasonal fluctuations  in the seven  bacterial types and attributed this to seasonal changes in the stage of maturity and  nutritive value of the plants.  Hungate (1975) discusses  pathways of bacterial fermentation in which certain bacterial functions form fatty acids which are in turn used by other bacteria to synthesize certain required amino acids.  Hungate also noted that the kinds and  amounts of non-carbohydrate nutrients also influence the components of the rumen microbial population.  It is apparent that the nutrient compo-  sition and stage of maturity of forages consumed have major influences on the  variety  and  abundance of microbes present  in the rumen.  While  specific data are lacking, i t seems reasonable to assume that rumen fluid containing a mixed population of microbes would have greater capacity to digest a mixed diet than one composed of a single species.  77  METHODS  Collection of Material  Several areas were selected for the collection of plants for analysis of forage characteristics. study site.  Collection areas were usually near a l i t t e r f a l l  Other conditions used in selecting sampling areas included:  one or more of the desired species was available for repeated collections on a monthly basis, and the area would be f a i r l y accessible during periods of deep snow.  The food  10 forage species collected monthly were those known from previous habits to be  important  food  items.  Species  five forage types included:  Shrubs - Gaultheria shallon Vaccinium alaskaense V. parvifolium Conifers - Pseudotsuga menziesii Thuja plicata Tsuga heterophylla Ferns - Blechnum spicant Polystichum munitum Lichens - Alectoria sarmentosa Forbs - Epilobium angustifolium  sampled within  the  78  Shrubs, conifers and ferns were collected in both forested and cutover areas.  Forested areas were mature conifer stands, cutover areas had been  logged 1-20 years earlier.  A. sarmentosa was present only in forested  areas and E. angustifolium was present only in cutover areas. E. angustifolium dies back each f a l l  and was available only from initiation of  growth in May until i t was killed by frost in October.  Conifers collected in forested areas came from a different location each month. Samples were selected to represent the kind of material that would be made available in l i t t e r f a l l .  Therefore, samples were taken from the  upper crowns of mature trees, felled in logging operations less than 24 hours prior to collection.  Alectoria sarmentosa samples were taken in  the same locations, from upper crowns of mature trees.  In addition a number of species were collected for analysis at the time field observations indicated they were being heavily used by deer.  Only current annual growth was sampled in a l l species collected, except where this growth was d i f f i c u l t to distinguish, as in A. sarmentosa and T. plicata.  Twigs and leaves were not separated, except as naturally  occurred with leaf f a l l from deciduous plants in fall-winter.  Sampling  of conifers and A. sarmentosa from felled trees involved clipping of twigs and/or foliage from different locations in the tops of at least five trees of each species.  79  Other species were sampled by randomly walking over the collection site, which normally was an area less than 2 hectares in size.  Current annual  growth was clipped from individual plants of the desired species as they were encountered.  In most cases a minimum of 50 plants was sampled per  species.  Clipped foliage was placed in polyethylene bags and taken to^the laboratory within 8 hours of collection.  Foliage of each species was thoroughly  mixed, placed in paper bags and dried in a forced-air oven at 60°C for 24 hours.  Dry matter content was determined  on a subsample weighed before  and after drying. Sample sizes were normally 50 to 100 g dry weight.  After drying, plant samples were ground through a 20-mesh screen in a Wiley mill.  Ground samples were thoroughly mixed and stored in sealed  glass jars in closed boxes until used.  Forage quality analyses for each species included:  Dry matter content Crude protein Solubility Cell wall components Neutral-detergent fiber Acid-detergent fiber Acid-detergent lignin Dry matter digestibility Volatile Fatty Acid fermentation products (see Chapter 4)  80  The latter two analyses were in vitro techniques, requiring fresh rumen inoculum.  Two  deer were collected monthly by  shooting.  In order to  minimize variation associated with sex and age, only adult females were taken.  An attempt was  made to standardize time of collection to that  period shortly after dawn, however, this was not always possible. Deer sometimes were d i f f i c u l t to find during hunting season and other periods of the year, necessitating collection of other times of day or with the aid of a spotlight at night.  Deer were transported to the laboratory immediately  after shooting.  At  the laboratory, body weight was obtained and the rumen was ligated at i t s junctions with the esophagus and weighed.  omasum, removed from the animal  and  An incision was made in the rumen wall and a rumen fluid sample  obtained by screening rumen digesta through four layers of cheesecloth into a prewarmed flask immersed in warm water. A 750- to 1000-ml inoculum sample was required; the procedure was repeated with two deer each month. In most cases, the time period between shooting the deer and collection of the inoculum sample did not exceed one hour. Remaining rumen contents were used in other analyses.  Total weight of rumen contents was deter-  mined by subtracting washed rumen tissue weight from total weight of rumen and i t s contents.  Analyses  conducted at the field  laboratory at Woss Lake included dry  matter, dry matter digestibility, solubility and Volatile Fatty Acid (VFA) fermentations.  Crude protein, cell-wall components and VFA  ratios and  concentrations were determined in the Animal Science lab at the University of  British  Columbia  Seattle, Washington.  or  in the Weyerhaeuser Company research lab i n  81  Details of the various analyses conducted are indicated below.  Analyses  were made using oven-dry plant material. Where appropriate, results were subsequently adjusted based on total dry weight (100°C in oven until constant weight reached).  Dry Matter Content (DDM)  Weight change between time of collection and 24 hours in a 60°C drying oven for a subsample of forage provided a measure of dry matter content.  Crude Protein  Duplicate determinations of total nitrogen in a l l plant species collected were made according to the micro-Kjeldahl procedure of Nelson and Sommers (1973).  Crude protein was calculated using the standard  conversion:  Percent Nitrogen x 6.25 = Percent Crude Protein. Following dry matter determination of a sample of rumen contents from each deer collected, crude protein determinations were made on the dried digesta.  Dry Matter Digestibility  The two-stage in vitro method of Tilley and Terry (1963) as outlined by Goering and Van Soest (1970) was followed.  Digestions were carried out  in 125-ml flasks in controlled-temperature ovens. Duplicate plant samples of 0.5 g were subjected to a 48-hour anaerobic fermentation period at 39°C in a CO^-saturated inoculum.  buffer solution (McDougall 1948) and fresh rumen  The second stage included digestion in an acid-pepsin solution  82  at  39°C  for an additional 48 hours.  Lacking an automatic agitation  system, flasks were swirled by hand at 1-hour intervals for the f i r s t 4 hours and at 8-hour intervals thereafter. samples  were filtered  crucibles.  under  At the end of this period,  suction through pre-weighed  fritted  glass  Residues were washed with distilled water and with acetone  until the f i l t r a t e was clear.  Oven-dry residue weights were then deter-  mined. Duplicate flasks containing only rumen inoculum and buffer solution (blanks) were subjected to the same procedure to provide a measure of dry matter contribution of the rumen inoculum. Percentage digestible dry matter is calculated as follows:  Percent _ beginning sample weight (0.5g) - residue wt - blank wt DDM beginning sample wt (0.5g)  -^QQ  Digestibility values were determined for duplicate samples of each species for each of two deer monthly.  In addition to single forage species, eval-  uations were also conducted for a series of diet mixtures, made up of groups of species in defined proportions.  Three series of dry matter digestibility determine  rates  of digestion.  trials were also conducted to  In these trials  duplicate samples of  individual species were digested for 12-, 24-, 36- and 48-hour periods and dry matter losses measured.  The 48-hour acid pepsin phase was not  used i n the digestion rate t r i a l s .  Individual deer were collected to  provide inoculum for each of these t r i a l s .  83  Cell Wall Contents  Determinations  of Neutral-detergent fibre  (NDF), Acid-detergent fibre  (ADF) and Acid-detergent lignin (ADL) on each plant species were made according to the procedure of Van Soest (1963) as modified by Waldren (1971).  Budgetary  limitations prevented the completion of ADL analysis  of forage samples collected from August, 1973 to March, 1974.  Solubility of Forage  To determine amounts of readily soluble components, a series of plants were incubated at 39°C for 48 hours in the in vitro buffer solution. Samples included representatives of the forage types:  shrubs, ferns,  lichens and conifers collected from slash and timber areas at each season of the year.  Following incubation, samples were filtered, as in the dry  matter digestibility procedure, and oven-dry residue weights determined.  Digestibility (DDM) of Forage Mixtures  To obtain information on the nutritive values of dietary mixtures, DDM of a series of diets of known composition were determined using the in vitro technique. Diets were formulated to mimic representative species mixtures that deer might consume at particular seasons.  Information on food habits  from previous studies and from current field observations suggested representative mixtures  although at the time this study was  started, food  habits data were limited or entirely lacking for some seasons. inoculum for the DDM  Rumen  determinations came from wild deer consuming mixed  diets and collected during the same month in which plants were collected.  84  RESULTS AND DISCUSSION  In the following discussion characteristics are treated within the five forage types as well as species.  Two types, lichen and forb, each contain  only one species; for these, type and species are treated as synonymous in the discussion.  Discussion of seasonal patterns follows that defined  earlier for food habits: spring (May and June), the period of growth i n i tiation and rapid early growth, summer (July-September), the period in which growth was completed and tissue maturation occurred and, fall-winter (October-April),  the period  during  which leaf  abcission occurred i n  deciduous species, lignification of woody tissues was completed and plants became dormant.  Values in the text are given as x (± SE x).  Dry Matter  Average annual levels of dry matter varied between forage types and by area of collection (Table 3-1).  Alectoria sarmentosa had the highest dry  matter content (74.0 ± 5.5%) followed by conifers (41.8 ± 0.8%), shrubs (33.9  ± 0.8%), ferns (22.9 ± 1.1%) and Epilobium angustifolium (21.7 ±  2.3%).  On an annual basis, a l l forage types were significantly different (p < 0.05) from each other in dry matter content, except forbs (E. angustifolium) and ferns, which did not differ from each other.  Both of these  types are herbaceous and are relatively short-lived perennials which prob-  Table 3-1.  S t a t i s t i c a l comparisons of c h a r a c t e r i s t i c s of forage c o l l e c t e d from f o r e s t e d (F) and cutover areas (C) i n d i f f e r e n t seasons. Comparisons a r e made between forage types w i t h i n each season and a n n u a l l y .  Dry  N  Season Forage Type  Matter  Crude P r o t e i n  (Percent of green weight) — F  C  F+C  6  6  12  F  C  x  (Percent of oven dry weight) —  F  F+C  C  F+C  1  (Percent o f oven dry weight) —  —  1  DDM  F  C  F+C  Spring Shrubs  2  3  Conifers  6  6  12  2A.A  a  ( 8.1) A7.6  b  ( 5.A) Lichens  2  -  2  28. 5 ( 7.2)  26. 5 ( 7.6)  15. 5 ( 5.3)  1A.5 (15.9)  15.0 (15.A)  A2.9 (17.A)  44. 5 (17.6)  43. 7 (16.7)  40.9 (10.7)  AA.2 ( 8.8)  5.2 ( 1.2)  7.2 ( 2.8)  6.2 ( 2.3)  A2.6 ( 8.4)  46.5 b (12.9)  44.5 (10.6)  2.1  -  -  48. 2 ( 3.2)  -  -  a  b  a  b  73. 6 (23.2)  17.0 ( 2.8)  -  C  b  (  Forbs  • -  2  2  -  Ferns  4  A  8  13. 2 ( 3.2)  17.0 ( A.A) ac  8  8  26. 6 ( A.l) 39.2 (10.1)  3  b  b  a  b  3  a  a  0.1)  a  a  a  a  -  2A.5 ( 0.7)  -  -  •  66.8 ( 3.2)  -  15. l ( A.l)  18.5° ( A.5)  20.0 ( A.A)  19.2° ( A.2)  25.4 ( 8.1)  21.5 ( 3.8)  23.4 ( 6.2)  36. 2 ( A.l)  31.A ( 6.A)  10.3 ( 2.A)  8.6  37.4 ( 8.5)  39.8  (  9.4 ( 2.0)  (12.9)  38.6 (10.6)  31.8 ( 3.5)  35. 5 ( 8.2)  5.5 ( 1.2)  5.9 ( 0.3)  5.7 ( 0.9)  AA.8 ( 7.9)  -  1.9 ( 0.6)  -  -  ac  a  a  d  C  ac  b  b  C  C  Summer Shrubs  16  a  Conifers  7  7  Lichens  3  -  3  88. l ( A.5)  Forbs.  -  2  2  -  IA  b  a  ab  c  22.7°  (0.6) Ferns  4  A  8  22.8 ( 8.3) a  27.8 ( 5.6) bc  ab  a  25.3 (7.1)  a  b  C  d  12.l ( 1.7) a  a  1.0) b  •  a  b  •  -  -  a  ac  ' 48.6 ( 9.1) a  75.8 ( 3.2) b  13.9° ( 3.3)  -  8.1 ( 0.7)  10. i ( 2.5)  a  ac  a  28.5 ( 8.4) C  46.7 ( 8.4) b  .  74.5 ( 3.5)  ' - -.  30. 7 (10.1)  29.6 ( 8.7)  b  •.-  a  C  d  Table 3-1.  continued.  Dry M a t t e r (Percent of green weight) —  Season Forage  Crude  Type  F  C  F+C  c  F  (Percent —  F+C  oven  x DDM  P r o t e i n  dry  of  ( P e r c e n t  w e i g h t )  c  F  oven  F+C  dry  o f  w e i g h t )  c  F  F+C  F a l l - W i n t e r  Shrubs  20  22  42  C o n i f e r s  21  21  42  7  L i c h e n s  Forbs  • -  -  35. 5 (  5.5)  (  45. 2 3.4)  (  -  -  28. 9 (  12  Ferns  12  43.3  3.2)  (  23. 2  24 (  -  26.3  d  5.8)  (  7.1  a  ( 4.5)  b  38.2° (20.8)  1  36.9  a  3.0) 41.3  b  7  1  38.3  a  6.7 ( 1.6)  35.5 (8.1)  38.3 ( 9.2)  37.0 ( 8.7)  (  6.1 1.1)  5.6 ( 1.0)  46.3 ( 4.7)  46.7 ( 9.9)  46.5 ( 7.6)  -  -  (  1.7)  (  5.2 0.8)  -  (  1.8 0.3) -  5.5  b  b  ( 3.8)  C  -  -  C  a  (  6.4 1.4)  3  (  )  24.7 ( 6.2)  C  d  6.4)  8.9 1.2)  a b  a  a  a  b  b  78. l (14.2)  -  c  74.0  b  -  -  '  -  )  (  -  C  a  b  -  )  (  8.1 1.0)  8.8 ( 4.0)  n  (  8.2 3.9)  37.3 (10.3)  39.7 (11.6)  38.5 (11.0)  (  6.2 1.5)  5.7 ( 1.3)  45.3 ( 6.1)  47.0 (10.0)  46.2 ( 8.3)  -  1.9° ( 0.3)  72.5 (15.6)  d  (  a  c  8.5 ( 1.2)  33.0 (11.0)  37. l (14.0)  C  a  a  35.l  a  (12.5)  A l l - y e a r  Shrubs  34  36  70  31. 5 (7.4)  C o n i f e r s  34  34  68  44.4 ( 6.2)  12  L i c h e n s  -  -  5  5  Ferns  20  20  20  ^Average V a l u e s by  d r y i n  a  d i g e s t i b i l i t y , w i t h  o f  d e v i a t i o n .  common  v a r i a n c e  and  21.7 ( 5.1)  21.7 ( 5.1)  24. 7 ( 7.0)  22.9 ( 6.9)  v a l u e  i n d i c a t e d  s u p e r s c r i p t S c h e f f e ' s  •  i s  mean (a,  b,  -  11.5 4.3) (  d  l e t t e r  t e s t .  C  d  C  d  (  1.9 0.3)  C  C  21. l ( 7.0)  column  a n a l y s i s  S t a n d a r d  -  (  5.3 1.0)  b  74.0 (19.1)  -  C  41.8 ( 6.7)  n  a  a  b  b  ( 6.4)  74. 0 (19.1)  m a t t e r  a  39.3  ( 6.8)  9.3 ( 4.2)  33.9  a  b  12  Forbs  36. 2 ( 5.4)  a  d  of c)  two a r e  b  C  16.5 ( 8.3)  10.5 5.3) (  11. o ( 4.8)  30.6 (10.1)  f o r a t  each p  S  of  d  two  0.05  deer  l e v e l  b  C  71.3° ( 4.8)  71.3 ( 4.8)  32.7 (13.1)  31. 6 (11.6)  d  each as  a  72.5 (15.6)  -  _  e  d i f f e r e n t  b  C  d  d  a  b  b  16.5 8.3) (  r e p l i c a t i o n s not  a  month.  d e t e r m i n e d  C  d  87  ably explains their similarity in dry matter content, although data presented later indicate ferns contain high levels of fiber. parisons of forage types also are presented  Seasonal com-  in Table 3-1.  Most types  were significantly different from each other in dry matter content, and this pattern was fairly consistent within the three seasons as well as within area of collection, i.e. forested or cutover. were expected,  considering  the varied l i f e  These differences  forms examined and their  obvious differences in structure, growth rates and relative amounts of woody tissue. The herbaceous types, forbs and ferns, did not differ from each other seasonally in dry matter content.  Seasonal patterns of variation in dry matter content within forage types were related to stage of phenological development of the plants, except in A. sarmentosa, which varied only slightly by season, the minimum value of 38% occurring when the plants were collected while wet (Table 3-2). Growth rates of fruticose lichens such as Alectoria spp. are extremely slow (Karenlampi 1971) so that the amount of new tissue contained in a sample is very low and would have negligible influence on dry matter content.  Also, Alectoria i s composed primarily of fungal tissues which would  not be expected to vary substantially in amounts of structural materials with time. The influence of precipitation on dry matter content was minor in most species, as excess surface water could be removed by briefly rolling weights.  clipped  foliage in absorbent paper prior to obtaining green  The exception  precipitation.  was A. sarmentosa, which apparently  absorbed  E. angustifolium was collected from initiation of growth  (May) until dieback (October) and increased from 17.1% to 28.9% dry matter as a result of maturation during this period.  Levels of dry matter were  .  S t a t i s t i c a l d i f f e r e n t  c o m p a r i s o n  s e a s o n s .  o f  c h a r a c t e r i s t i c s  Comparisons  N  Dry  a r e  made  of  f o r a g e  between  M a t t e r  F  C  F+C  g r e e n  F  and  Crude  ( P e r c e n t o f  c o l l e c t e d  seasons  from a r e a  C  oven F+C  dry  F  (F)  and  c u t o v e r  c o l l e c t i o n  f o r  each  x  of  (C)  DDM  ( P e r c e n t  w e i g h t )  oven  C  F+C  a r e a 3  f o r a g e  P r o t e i n  (Percent  w e i g h t )  f o r e s t e d of  dry  F  i n  t y p e .  1  of  w e i g h t )  C  F+C  Shrubs S p r i n g  6  6  12  a  24.4  2  a  ( 8.1)" Summer  8  8  16  a  26.7  20  22  42  b  35.5  36.3++ ( 4.1)  b  38.3++ ( 3.0)  b  ( 5.5) Annual  34  36  70  3  a  ( 7.2)  ( 4.1) F a l l - W i n t e r  28.5++  31.5  31.4 (6.4)  b  C  ( 5.4)  a  15.5  ( 5.3) 10.3+ ( 2.4)  a  14.6  ( 5.9)  b  36.9  ( 4.5)  36.2++  ( 7.4)  26.5  ( 7.6)  c  7.1+  ( 1.7)  b  15.0  9.4  b  C  a  a  ( 8.5)  6.7  35.5  a  ( 1.6)  44.5  a  (17.6)  37.4  a  ( 2.0)  6.4  ( 1.4)  42.9 (17.4)  a  ( 5.4)  8.6  ( 1.0) c  a  39.8  38.6 (10.6)  a  (12.9) a  ( 8.1)  38.3  43.7  (16.7)  a  ( 9.2)  37.0  ( 8.7)  33.9  9.3  8.2  8.8  37.3  39.7  38.5  ( 6.8)  ( 4.2)  ( 3.9)  ( 4.1)  (10,3)  (11.6)  (11.0)  C o n i f e r s  S p r i n g  6  6  12  a  47.6+  40.9 (10.7)  8  ( 5.4) Summer  7  7  14  b  39.2  (10.1) F a l l - W i n t e r  A n n u a l  21  34  21  34  42  45.2++ ( 3.4)  a  68  44.4++ ( 6.2)  b  31.8  ( 3.5) 41.3 ( 3.2)  a  38.3 ( 6.4)  a  44.2  a  5.2  a  7.2  3  6.2  ( 8.8)  ( 1.2)  ( 2.8)  ( 2.3)  35.5 ( 8.2)  5.5 ( 1.2)  "5.9 ( 0.3)  ( 0.9)  43.3 ( 3.8)  5.2 ( 0.8)  ( i.i)  5.6 ( 1.0)  41.8 ( 6.7)  5.3 ( 1.0)  6.2++ ( 1.5)  ( 1.3)  b  3  a  a  a  6.1++  a  5.7  a  a  42.6  4 6 , .5 (12, .9)  a  ( 8.4) a  44.8  (  7.9) -  46.3 ( 4.7)  a  5.7  45.3 ( 6.1)  3  4 8 . .6  ( 9.• 2) 4 6 . .7 ( 9..9)  a  47. 0 ( 1 0 . 0)  44.5 (10.6)  a  46.7 ( 8.4)  a  46.5 ( 7.6)  a  46.2 ( 8.3)  L i c h e n s  S p r i n g  Summer  2 3  2 3  73.6 (23.2)  a  a  88.1  ( 4.5) F a l l - W i n t e r  7  7  a  38.2^  (20.8) A n n u a l  12  12  a  2.1  48.3 ( 3.2)  a  ( 0.1) a  2.0  ( 0.6) a  1.8  b  75.8  ( 3.2) b  78.1  ( 0.3)  (14.2)  74.0  1.9  (19.1)  ( 0.4)  72.5 (15.6) CO  00  Table  N  F  C  F+C  Spring  2  2  Summer  2  2  Fall-Winter  1  1  Annual  5  5  3-2.continued.  Dry M a t t e r  Crude P r o t e i n  x DDM  (Percent of green weight)  (Percent o f oven d r y w e i g h t )  (Percent o f o v e n d r y we i g h t )  F  C  F+C  F  C  F+C  F  1  C  F+C  Forbs 17.1 ( 2.8)  a  24.5 ( 0.7)  22.8 (0.6)  a b  66.8 ( 3.2)  a  a  13.9 ( 3.3)  74.5 ( 3.5)  b  28.9 ( - )  5.5 ( - )  21.7 ( 5.1)  16.5 ( 8.3)  b  a  74.0 ( - )  b  a  71.3 ( 4.7)  Ferns Spring  4  A  8  Summer  A  A  8  Fall-Winter  12  12  2A  b  Annual  20  20  40  21.1 ( 7.0)  i3.2 ( 3.2)  a  22.9 ( 8.3)  b  23.2 ( 5.8)  17.0 ( 4.4)  a  15.1 ( A.l)  a  b  27.9 ( 5.6)  b  26.3+ (6.4)  24.7 ( 6.9)  b  25.3 . ( 7.1)  18.5 ( 4.5)  a  20.0 ( A.A)  a  19.2 ( 4.2)  a  10.1 ( 2.5)  a  a  a  21.1+ ( 1.7)  8.1 ( 0.7)  b  24.7 : ( 6.2)  8.9+ ( 1.2)  8.1 ( 1.0)  8.5 ( 1.2)  22.9 ( 7.1)  11.5 ( 4.3)  10.5 ( 5.3)  11.0 ( 4.8)  b  C  b  b  b  b  25.4 ( 8.1)  28.5 ( 8.4)  23.4 ( 6.2)  21.5 ( 3.8)  a  a  ab  30.8 (10.1)  a b  29.6 ( 8.7)  33.0 (11.OV  b  b  30.6 (10.1)  32.7 (13.1)  31.6 (11.6)  37.1 (14.0)  ' A v e r a g e d r y m a t t e r d i g e s t i b i l i t y , v a l u e i s mean o f two r e p l i c a t i o n s f o r e a c h o f two d e e r p e r month. V a l u e s i n a c o l u m n w i t h a common s u p e r s c r i p t l e t t e r ( a , b, c ) a r e n o t d i f f e r e n t a t p <0.05 l e v e l a s d e t e r m i n e d by a n a l y s i s o f v a r i a n c e and S c h e f f e ' s t e s t . S i g n i f i c a n t d i f f e r e n c e between f o r a g e c h a r a c t e r i s t i c i n f o r e s t e d and c u t o v e r a r e a s i n d i c a t e d a s : + (p < 0.05) a n d ++ ( p £ 0.01). A n a l y s i s by t - t e s t . ^ S i g n i f i c a n c e i n d i c a t o r i s b e s i d e t h e measure h a v i n g t h e g r e a t e r v a l u e . Standard d e v i a t i o n .  35.1 (12.5)  90  statistically 3-2).  different  (p < 0.05) between a l l seasons in shrubs (Table  Conifers were significantly lower in dry matter in summer than in  the other seasons even though one would expect lower dry matter in spring as shown by Russel and Turner (1975). This difference probably results from the inclusion of some old tissue in the May sample as buds were not fully  opened and also the inclusion of dry matter measures for Thuja  plicata, for which new  growth could not be clearly distinguished from  older tissue, the latter being included in the sample in both May and June.  A better separation of old and new tissue of T. plicata apparently  occurred  in summer.  Epilobium angustifolium  was  significantly  lower  (p < 0.05) in dry matter in spring than in the fall-winter season. Ferns were significantly lower in dry matter in spring than in the other two seasons.  Generally, the magnitude of seasonal change i n dry matter con-  tent was lower in shrubs and conifers which contain higher levels of fibre than forbs.  Ferns contain high levels of fibre as will be discussed  later, but apparently take up large amounts of water during the growing period, resulting in a low dry matter content.  Comparisons  of dry matter content of plants collected in forested and  cutover areas were made for shrubs, conifers and ferns (Table 3-2). Dry matter content of shrubs calculated on an annual basis was higher in cutovers than in forested areas. This may be the result of increased water stress  in cutover areas.  Shrubs  in cutover areas had a  "sunburned"  appearance with discolored leaves, compared to plants growing in forested areas, which appeared more succulent and retained a green color to the leaves through the entire spring and summer periods. Ferns from cutovers showed a similar discoloration, and a similar trend towards higher values  91  in cutovers, but differences were statistically significant only in the fall-winter  season.  Conifers from forested areas were higher in dry  matter than those from cutovers on an annual basis, possibly because tissues were collected from mature trees which appeared to have a greater proportion of woody tissue than the 10- to 20-year-old trees sampled in cutover areas, even though current annual growth was sampled in each area. Water loss prior to obtaining green weights could have been higher in conifer foliage from forested areas, which was taken from mature, felled trees which had been cut up to 24 hours prior to sampling.  Seasonal comparisons of plants from cutovers with those in forested areas show trends similar to those observed in annual comparisons.  During most  seasons dry matter contents were highest i n shrubs and ferns from cutover areas and conifers from forested areas, although the differences were not always  statistically  significant  (Table  3-2).  These trends probably  result from the same factors of insolation and soil moisture which appear to be responsible for the annual differences observed.  Patterns of nutrient and dry matter content of individual species within forage types are presented in Table 3-3.  Statistical comparisons between  seasons and between forested and cutover areas are summarized for each species. nificantly  Dry matter levels were similar and in most cases were not sigdifferent between species within a forage type as will be  discussed further below.  When species i n a type were compared as to annual dry matter content i n forested versus cutover areas, conifer species did not differ from each  Table  3-3.  C h a r a c t e r i s t i c s o f f o r a g e s p e c i e s c o l l e c t e d i n f o r e s t e d ( F ) and c u t o v e r (C) a r e a s a t seasons. S t a t i s t i c a l c o m p a r i s o n s a r e made b e t w e e n s e a s o n s and a r e a o f c o l l e c t i o n . Dry  of C  F+C  2  4  Matter  Crude  (Percent green weight)  different  Protein  x  (Percent of oven d r y w e i g h t )  DDM  (Percent of oven d r y w e i g h t )  F+C  F+C  F+C  Shrubs  Gaultheria  shallon  Spring  2  26.6  a b  (15.8) Summer  3  3  6  ( Fall-Winter  8  14  ( Annual  11  13  24  2  2  1.5)  4.1)  (  (  (  35.7+  8.3)  (  7.2)  (  (  (  6.9)  "26.7 ( 7.8)  (  23.9 6.5)  a  (  5.0  (  7.4  a  0.03) b  (  (  5.3 (  (  "22.5 (10.6)  7.6  a  5.1  1  (  6.5  1.8)  (  2.5)  "14.9 ( 5.5)  (  16.2 4.1)  (  27.8+ *  a  23.0  a  (  26.6  b  4.0)  (  1.7)  (  (  29.7  4.8)  (  2.4)  30.4  b  4.8)  6.3)  26.2  a  33.3+  (  26.2 (  "22.7  2.1)  24.5  3  ( 1 9)  0.6)  6.3  3.2)  9.9 4.4)  0.6) b  0.7)  6.8 (  a  2.9)  7.8  0.4)  33.8  4.9)  (  0.8) b  1.4)  "9.0  6.9)  a b  37.0  b  1.5)  (  29.4  a  37.3  a  21.1 (  Summer  3  Fall-Winter  3  7  14  Annual  12  12  5.9)  26.4 ( 0.5)  a b  33.6  b  ( 24  37.2 ( 4.1)  b  37.5+  b  7.1)  (  29.8 (  5.4) 28.1  6.1)  (  "56.5 (12.0)  (  5.8)  a b  (  12.4 ( 1.8) C  5.7)  (  32.7  5.7)  (  3.9)  b  9.7 0.2)  b  6.9  b  35.6  (  35.7++  7.5)  (  31.8 ( 6.5)  b  3.4)  "17.5  (  7.8 1.1)  (  10.5++  7.2)  (  4.1)  1.6)  11.0 ( 1.9)  b  C  (  3.7)  ( a b  7.3  a b  36.2  (  9.7 (  9.9)  41.0 ( 1.7)  b  1.4)  8.9 (  "51.0  47.7 ( 3.6)  (  7.4)  44.3 ( 4.4)  35.8  °36.0 (  39.9  3.9)  9.5)  b  (  b  4.9)  53.7  9.0)  7.0)  42.2  41.9  (11.5)  (U.3)  parvifolium  Spring  2  2  4  25.6  3  ( Summer  2  2  4  Fall-Wi nter  7  7  14  b  11  0.6)  36.4  ( 11  2.8)  30.2  a b  (  Annual  (  °10.8  alaskaense  Spring  V.  6.4)  31.5 (  Vaccinium  34.3  a  36.6  a  29.0 (12.2)  2  (13.1)  24.5  b  31.3  a  3  22  6.1)  3  27.5  ( b  b  6.6)  5.9)  40.1+  (  33.3 (  1.5)  37.7  (  a  3.4)  26.5  ( b  33.9  ( b  5.9)  5.5)  18.2  (  (  5.1)  10.9++ ( 0.4) b  (  35.3 (  6.5)  3.7)  b  38.2  37.3++ (  2.1)  3  a  8.6 ( 0.4) b  (  10.5 (  4.2)  4.4)  18.9 (  b  8.3+ 1.1)  l9.7  (  b  (  7.1 1.0) 9.7  (  5.2)  "54.0  (  (  9.8  7.7 1.2)  ( b  4.7)  5.9) 45.5  (  51.0+ (1.4)  7.2)  a  46.4  (  54.6  3.5)  a  3.5)  4 2.5  (  10.1 (  6.0)  46.5  a b  1.3) b  (  "55.3  3.4)  8.5)  (  ( b  3.4)  44.4  (  48.6 (7.4)  4.1)  48.7  3 b  7.3) 47.1  (  7.3)  Table 3-3. N  continued.  Dry Matter  Crude P r o t e i n  (Percent of green weight) F  C  F  F+C  x DDM  (Percent of oven d r y weight)  (Percent o f oven dry w e i g h t ) — -  F  C  F+C  44.7 ( 9.4)  5.8 ( 0.6)  9.8 ( 2.9)  7.8 ( 2.9)  a  33.6 ( 6.6)  6.3 ( 1.5)  6.3 ( 0.1)  6.2 ( 0.9)  3  43.1 ( 4.6)  5.9 ( 0.7)  7.4++ ( 0.3)  6.6 ( 0.9)  a  41.7 ( 6.9)  6.0 ( 0.7)  7.6++ ( 1.5)  6.8 ( 1.4)  48.3 ( 4.9)  4.4 ( 0.9)  4.8 ( 0.5)  4.6 ( 0.6)  3  5.4 ( 0.4)  a  a  F+C  C  1  F+C  C  Conifers Pseudotsuga  menziesii  Spring  2  2  4  a  Summer  2  2  4  b  Fall-Winter  7  7  14  11  11  22  Spring  2  2  4  Summer  3  3  6  FalJ-Winter  7  7  14  12  12  24  2  4  Annual  Thuja  39.4 (12.2)  a  33.5 (10.3)  a  33.6 ( 4.9)  b  45.4+ ( 4.2)  a  40.8 ( 4.1)  a  44.1+ ( 7.2)  a  39.3 ( 5.9)  a  a  a  a  b  b  a  3  a  44. 5 ( 4.2)  a  46. 3 ( 3.9)  a  47. 4 ( 1.9)  a  46. 7 ( 2.6)  45.9 ( 8.9)  4 7 .3 (14 • 5)  a  5 2 .0 ( 2• 1)  a  4 7 .2 ( 4.1)  a  48 .1 ( 5• 9)  49.1 ( 4.2) 47.3 ( 3.0) 47.4 ( 4.5)  50.2 ( 2.2)  ab  46.4 ( 7.3)  a  32.3 ( 0.3)  b  39.6 ( 8.0)  5.0 ( 0.4)  5.7 ( 0.1)  43.1 ( 3.1)  4.9 ( 0.4)  5.7+r ( 0.6)  5.3 ( 0.7)  43.1 ( 5.5)  4.9 ( 0.5)  5.6++ (0.6)  5.2 ( 0.6)  39.8 (11.0)  5.4 ( 2.1)  7.0+ ( 2.4)  6.2 ( 2.1)  5.8 ( 0.6)  5.6 ( 1.3)  a  a  46.9+ ( 0.9).  b  41.2 ( 2.8)  45.0+ ( 2.3)  c  b  46.3++ ( 2.7)  ab  39.8 ( 5.8)  a  a  a  a  b  b  a  ab  b  5 7 .1 ( 1•2)  a  54 .8+ ( 3• 7)  a  5 7 .6++ ( 2. 8 )  a  50. 0 ( 6.4)  a  50. 5 ( 3.5)  a  50. 3 ( 2.4)  a  50.3 ( 3.0)  56 . 8 ( 2.9)  53.6 ( 5.6) 52.7 ( 4.0) 53.9 ( 4.5) 53.5 ( 4.4)  heterophylla  Spring  2  Summer  2  2  4  Fall-Winter  7  7  14  11  11  22  Annual  a  plicata  Annual  Tsuga  50.0 ( 2.0)  42.6 ( 7.8)  a  ab  37.0 (16.5)  5.5 ( 2.1)  42.0 (3.1)  b  43.6 ( 3.8)  4.8 ( 0.9)  5.1 ( 0.4)  4.9 ( 0.7)  40.6 ( 7.8)  5.0 ( 1.2)  5.6+ ( l.D  5.3 ( 1.2)  a  38.8 ( 7.9)  a  a  ab  b  33. 3 ( 1.8)  a  31.3 ( 9.0)  4 5.1 ( 3.9) 42.5+ ( 7.5)  a  a  b  a  a  29.3 ( 5.4)  33.3 (14.0)  a  ab  a  a  a  a b  3 5 .0 . (11• > a  3  a  3 5 .4 ( 3.5)  a  a  41. ].++ ( 3.6)  a  (  38. 5 9)  35.2 ( 3.1)  3 5 .8 ( o• 4)  34. 8 ( 5.3) b  34.1 ( 6.7)  a  35 .4 ( 4.5)  38.2 ( 4.5) 36.9 ( 4.8)  T a b l e 3-3. N  continued.  Dry M a t t e r  Crude P r o t e i n  (Percent o f green weight) F  C  F+C  F  C  ,x DDM  1  (Percent of oven dry weight) F+C  F  C  F+C  '  (Percent o f oven d r y weight)  F  C  F+C  Lichens Alectoria  earmentoaa  Spring  2  Summer  2  3  3  73.6 (23.2)  a  a  a  (  88.1  Fall-Winter  Annual  7  7  12  12  (  38.2 (20.8)  a  74.0  2.0  b  1.8  (  3.2)  75.8  (  3.2)  78.1 (14.2)  b  0.3) 1.9  (19.1)  48.2  (  0.6) a  (  a  0.1) a  ( A.5)  2.1  72.5  0.3)  (15.6)  Forbs Epilobium Spring  angustifolium . 2  2  a  17.1  ( Summer (July-Oct)  2  Fall-Winter  1  2  22.8  a b  1  b  5  24.5  ( b  (0.6)  5  -  b  )  (  5.1)  (  a  3.3) 5.5 -  ...  16.5 8.3)  3.2)  74.5  ( a  )  66.8  (  13.9  21.7 (  a  0.7)  (  28.9  ( Annual  a  2.8)  3.5)  74.0  (  71.3  (4.8)  )  Table 3-3.  continued.  Dry Matter  Crude  (Percent of green weight)  F  C  F+C  F  C  Protein  x DDM  (Percent of — oven dry weight) F+C  F  (Percent of oven dry weight)  —  C  F+C  F  C  F+C  Ferns Blechnum  epicant  Spring  2  2.  4  a  Summer  2  2  4  a  Fall-Winter  6  6  12  10  10  20  Annual  l0.5 ( " )  i6.5+ (1.1)  a  16.8 ( 1.2)  18.6 ( 1.5)  b  a  23.1+ ( 0.4)  21.9+ ( 3.3)  16.6 ( 3.5)  17.5 ( 7.1)  20.5 ( 5.5)  a  12.4 ( 0.1)  7.5 ( 0.2)  9.9 ( 2.8)  20.3 ( 3.0)  9.0+ ( 1.5)  7.7 ( 1.3)  8.3 ( 1.5)  b  42.0 ( 7.9)  18.8 ( 4.1)  11.4 ( 4.3)  10.8 ( 6.8)  11.1 ( 5.6)  37.0 (10.6)  b  ab  b  21.0++ ( 3.5)  23.6 ( 1.8)  a  19.9 ( 3.7)  b  b  l3.5 ( 3.5)  b  b  23.0 (12.0)  a  b  b  a  23.5 ( 4.9)  a  38.8 ( 5.3)  b  b  48.5 (10.1)  b  41.5 (13.0)  39.3 (11.8)  19.5 ( 1.4)  23.6 ( 5.7)  a  35.8 ( 0.4)  ab  b  ab  23.2 ( 7.5)  37.2 ( 3.5)  45.2 ( 9.3)  Po lye tichion mm i turn Spring  2  2  4  Summer  2  2  . 4  Fall-Winter  6  6  12  10  10  20  Annual  15.9 (1.1)  b  b  28.9 ( 7.6)  a  b  27.7 ( 4.8)  a  30.7 ( 5.7) 28.5 ( 7.6)  a  b  25.6 ( 6.7)  17.6 ( 7.4)  32.6 ( 1.3)  16.7 ( 4.4)  a  a  19.5 ( 2.5)  a  30.8 ( 4.9.)  b  11.9 ( 2.9)  8.7 ( 0.2)  b  29.2 ( 5.2)  8.8 ( 0.9)  27.0 ( 7.1)  11.6+ ( 4.6)  b  16.4 ( 1.5)  a  17.9 ( 2.5)  a  10.3 (2.5)  a  a  22.7 ( 4.6)  22.0 ( 2.,8)  8.5 ( 0.5)  8.7 ( 0.7)  a  24.0 ( 2.9)  a  25.7 ( 4.4)  24.9 . ( 3.6)  10.1 ( 3.3)  10.9 ( 4.0)  24.2 ( 3.5)  23.9 ( 4.5)  24.1 ( 3.9)  b  b  b  b  27.8 ( 5.3)  21.3 ( 0.4)  a  'Average dry matter d i g e s t i b i l i t y , v a l u e i s mean of two r e p l i c a t i o n s per deer per month. V a l u e s i n a column w i t h a common s u p e r s c r i p t l e t t e r ( a , b, c) are not d i f f e r e n t at p < 0.05 as determined by a n a l y s i s of v a r i a n c e and S c h e f f e ' s t e s t . 'Standard d e v i a t i o n . ' ' S i g n i f i c a n t d i f f e r e n c e between forage c h a r a c t e r i s t i c i n forested and cutover areas i n d i c a t e d as: + (p <; 0.05) and ++ (p <. 0.01) as determined by t - t e s t . S i g n i f i c a n c e i n d i c a t o r i s beside the measure having the greater value.  2  96  other nor  did shrub species.  Polystichum  muniturn was  higher  (p <  i n dry matter content than Blechnum spicant i n both forested and  0.05)  cutover  areas.  Annual levels of dry matter content between a l l species were also compared statistically  using analysis of variance and Scheffe's test (Table 3-4).  Patterns of v a r i a t i o n were similar among species within forage types, i . e . conifer species did not d i f f e r from each other nor did shrub species, but individual species i n both types d i f f e r e d from a l l other species i n the other types.  Annual levels of dry matter ranged from 74.0  sarmentosa to 18.8  (±5.5%) i n A.  (±4.2%) i n Blechnum spicant.  In summary, forage species examined i n t h i s study exhibited patterns of v a r i a t i o n i n dry matter content that were related to phenological stage of the plant.  Similar patterns were documented by Short et aJL. (1975) i n a  number of browse species i n the southeastern United States. patterns of change were similar within plant types.  Levels  and  Woody plants (shrubs  and conifers) underwent changes of dry matter content of lesser magnitude than herbaceous species (forbs and ferns).  Crude Protein  Annual and seasonal levels of crude protein for forage types and species are  presented  and  statistically  compared  i n Tables  3-1,  3-2  and  3-3.  Annual levels of crude protein and other components are presented graphically  i n Figure 3-5.  On  A l e c t o r i a sarmentosa, was  an annual basis, the lowest  single  lichen examined,  (1.9 ± 0.5 percent) and the single forb  Table 3-4. S t a t i s t i c a l comparisons of annual n u t r i e n t l e v e l s of forage s p e c i e s . Values are averages f o r p l a n t s c o l l e c t e d i n f o r e s t e d and cutover areas combined.  DRY  MATTER  ALSA  (%  THPL  OF  GREEN  WEIGHT)  PSME  1  TSHE  VAPA  ' / / / / / / / / / / / / / / / / / / / / / / / /  ZA±0  A3.1  2  CRUDE  PROTEIN  EPAN  OF  OVEN  DRY  21.7  18.8  TSHE  THPL  ALSA  5.3  5.2  1.9  v.v.v.v.v.w.  DRY M A T T E R  OF  33.8  32.7  "\\v  OVEN  ALSA  EPAN  T H P ' L ' ^ ^ ^ S M E '/////////////.  72. 5  71.3  53.5  V//,  VAAL  10.1  (%  BLSP  WEIGHT)  VAPA  1Q.9  EPAN  27.0  v \ \ V w \ V w \ \ \ \ \  POMU  POMU  35.3  .v.v.v.w.v.w  11.1  DIGESTIBLE  (%  40.6  VAAL  WW  w\\\\\\\\\\\v  BLSP  16.5  41.7  GASH  V . V . V . V . V . V . V . V . V . V . V . V .  PSME y  9.7  DRY  /  /  GASH  /  6.8  6.5  //////////////.  WEIGHT) V A P A V A A L  \\\\ BLSP  //// TSHE ////  GASH  39.3  36.9  28.1  .WW  POMU  47.4  47.1  41.9  24.1  Forage species codes and type d e s i g n a t i o n s are as f o l l o w s : SHRUBS GASH = Gaultheria shallon CONIFERS '////, PSME = Pseudotsuga menziesii LICHEN ALSA = Alectoria sarmentosa FORBS EPAN = Epilobium angustifolium FERNS .WW BLSP = Blechnum spicant !  VAAL - Vaccinium alaskense THPL = Hiuja plicata POMU = Polystichum  VAPA = V. parvifolium TSHE = Tsuga heterophylla  nrunitum  S p e c i e s not u n d e r l i n e d by common l i n e a r e s t a t i s t i c a l l y d i f f e r e n t (p <. 0.05) by a n a l y s i s of v a r i a n c e and Scheffe's t e s t .  as determined  Conifers  Shrubs  cell contents = hemicellulose =  F i g u r e 3-5.  Cutover  Forested  Forested  O  cellulose  Crude Protein  ^ \  Digestible Dry Matter  lignin =  Average annual composition of f o r a g e types c o l l e c t e d from and c u t o v e r a r e a s . Values are percent of dry matter.  forested VO  oo  99  examined, Epilobium angustifolium, crude protein content (Table 3.1).  was  highest  (21.7  ± 2.3 percent) in  These species also exhibited minimum  (1.8 ± 0.2 percent) and maximum (24.8 ± 0.5 percent) levels respectively, of crude protein on a seasonal basis, and were statistically different from each other (p < 0.05) in A.  sarmentosa are  in a l l seasons.  consistent  Low  levels of crude protein  with those measured in several other  lichen species (Scotter 1972). In Alectoria jubata, Scotter (1965) measured slightly higher levels of crude protein (3.9 to 6.3 percent) than those observed in A. sarmentosa in the present study.  Significant dif-  ferences occurred seasonally between other types, but not in a consistent pattern, except that conifers were always lower in crude protein than shrubs and ferns (Table 3-1).  On an annual basis, crude protein levels were higher in shrubs and ferns collected in forested than in cutover areas, but these differences were not significant (Table 3-2).  Conifers in cutovers contained more crude  protein than in forested areas (p < 0.05).  When species < 0.05)  were compared within forage type several significant (p  differences in average annual levels of crude protein are evident.  Among shrubs, Gaultheria shallon had a lower crude protein content than either Vaccinium alaskaense or V. parvifolium (Table 3-4).  Crude protein  of Pseudotsuga menziesii exceeded that of Thuja plicata and Tsuga heterophylla among conifers but among ferns Blechnum spicant and Polystichum muniturn did not differ in crude protein level on a year-long basis.  100  Seasonal levels of crude protein in individual forage types varied With phenological stage of the plants. Most types contained highest average crude protein levels in spring, intermediate values in summer and lowest values in fall-winter (Table 3-2).  Short et a l . (1975) reported similar patterns in a number of browse species they studied. Differences were significant (p < 0.05) in shrubs between a l l three seasons, ferns.  Conifers showed  and between spring and summer in forbs and  little  seasonal  difference in crude protein  levels, perhaps related to their relatively high fibre content and also to  the difficulty in separating old and new tissue during collections.  Rapid  short-term  declines i n nitrogen content between bud burst and  i n i t i a l stages of expansion of P. menziesii shoots noted by Krueger (1967) were not detected i n forested areas but were apparent in cutovers.  When compared seasonally, crude protein i n shrubs and ferns was s i g n i f i cantly higher in forested areas than in cutovers during summer and f a l l winter periods and significantly higher i n conifers in cutovers during the fall-winter period (Table 3-2). Crude protein levels did not differ between forested and cutover areas in the other seasons. Generally higher levels of crude protein in a number of browse species were observed in cutover areas compared to mature timber stands in Oregon (Einarsen 1946). Cowan et al. (1950) found that the youngest successional stages generally produced the moose forage of highest crude protein content in northern British  Columbia.  Brown  (1961) was  unable  to show clearly-defined  patterns in forage quality associated with forest aging in western Washington, possibly due to his limited sample sizes.  Gates (1968) did not  101  observe  s i g n i f i c a n t changes between crude p r o t e i n  sampled  from  study,  s i t e s burned  canopies  present,  l e v e l s i n species  4 and 14 y e a r s p r e v i o u s l y .  o f mature stands v a r i e d  he  I n the present  as t o t h e degree o f openings  and i n few cases was canopy c l o s u r e  complete.  This  may have  c o n t r i b u t e d t o t h e l a c k o f c o n s i s t e n t d i f f e r e n c e s observed between p l a n t s from f o r e s t e d areas and c u t o v e r s .  Crude p r o t e i n l e v e l s v a r i e d by season and area o f c o l l e c t i o n i n i n d i v i d u a l species  (Table 3-3).  from f o r e s t e d 3-8.  Within  Monthly p a t t e r n s  of v a r i a t i o n i n i n d i v i d u a l species  and c u t o v e r areas a r e shown g r a p h i c a l l y i n F i g u r e s t h e shrub t y p e , G a u l t h e r i a  s h a l l o n from c u t o v e r s  3-6 t o  contained  l e s s p r o t e i n i n f a l l - w i n t e r t h a n i n o t h e r seasons and i n f o r e s t e d areas crude p r o t e i n l e v e l was s i g n i f i c a n t l y h i g h e r winter period  ( T a b l e 3-3).  Levels  i n s p r i n g than i n the f a l l -  i n s p r i n g and summer were n o t d i f f e r e n t  (p < 0.05).  I n V a c c i n i u m a l a s k a e n s e , crude p r o t e i n l e v e l s were d i f f e r e n t between a l l three  seasons i n t h e f o r e s t .  I n c u t o v e r a r e a s , s p r i n g l e v e l s were  higher  t h a n i n summer and f a l l - w i n t e r ; t h e l a t t e r two seasons were n o t d i f f e r ent.  Levels  o f crude p r o t e i n  d i f f e r e d between s p r i n g  (higher)  and t h e  o t h e r two seasons i n V. p a r v i f o l i u m , c o l l e c t e d i n b o t h f o r e s t e d and c u t over  areas.  from f o r e s t e d in  Among  conifers, protein  areas d i d n o t v a r y w i t h  c o n t e n t o f Pseudotsuga  season b u t i n c u t o v e r s was h i g h e r  s p r i n g t h a n i n f a l l - w i n t e r and summer.  not v a r y s e a s o n a l l y cantly higher  menziesii  S i m i l a r l y , Thuja p l i c a t a d i d  i n p r o t e i n c o n t e n t i n t i m b e r e d areas b u t was s i g n i f i -  i n s p r i n g t h a n i n f a l l - w i n t e r and summer i n c u t o v e r a r e a s .  Tsuga h e t e r o p h y l l a  from  cutover  areas  d i f f e r e d o n l y between s p r i n g and  102  Composition (%)  GAULTHERIA SHALLON  FORESTED  CUTOVER  50  3U —  new growth 40  30 -  20  10  H  j riew* g r o w t h  VACCINIUM ALASKAENSE  • /l\  50  J  10 J  "1—f—I  0  VACCINIUM PARVIFOLIUM  10  i  J  F  M  A  M  J  S  J . A  0  N  D  '  J  F  M  A  M  J  J  A  S  O  N  - - Time ( m o n t h s ) - -  F I G U R E 3-6.  MONTHLY PATTERNS OF V A R I A T I O N CUTOVER AREAS • *  LIGNIN  A  IN COMPOSITION OF SHRUBS COLLECTED IN FORESTED AND  CRUDE PROTEIN —  •  -  HEMICELLULOSE  • — - DRY MATTER .  o  DIGESTIBILITY  CELLULOSE  D  103 Composition  (%)  60  I  FORESTED  PSEUDOTSUGA MEN'/.rESTT new  J  new g r o w t h  growth  50  40  30 -  TSUGA HETEROPHYLLA  60 -a  new  FORESTED  50  new  growth  growth  50  40  40  V  30  20  10  60 -|  30  20  4  10 H  - Time (months) -  FIGURE 3-7.  MONTHLY PATTERNS OF VARIATION IN COMPOSITION OF CONIFERS COLLECTED IN FORESTED AND CUTOVER AREAS. — A — CRUDE PROTEIN — DRY MATTER DIGESTIBILITY • LIGNIN - . o HEMICELLULOSE o CELLULOSE  ALECTORIA SARMENTOSA 100  FORESTED  EPIL031UM ANOUSTIFOLIUM  /\  80  60  100  CUTOVER  80-  60  40 -  20 H  J  F  M  A  «  J  J  A  S  0  N  D  J  - - Time  FIGURE 3-8,  F  M  A  M  J  J  A  S  O  N  D  (months)  MONTHLY PATTERNS OF V A R I A T I O N IN COMPOSITION OF F E R N S , FORBS AND LICHENS COLLECTED IN FORESTED AND CUTOVER AREAS, •  LIGNIN  A •o  CRUDE PROTEIN HEMICELLULOSE  B 0  DRY MATTER DIGESTIBILITY CELLULOSE  105  fall-winter periods.  Blechnum s p i c a n t i n c u t o v e r s d i f f e r e d between  s p r i n g and  between s p r i n g and  fall-  winter  and  the o t h e r seasons i n f o r e s t e d  areas.  P o l y s t i c h u m muniturn i n c u t o v e r s had h i g h e r crude p r o t e i n i n s p r i n g  than i n the o t h e r seasons i n b o t h c u t o v e r and f o r e s t e d areas (Table 3-3).  Average annual  crude p r o t e i n c o n t e n t s  tistically  i n T a b l e 3-4.  more  ±  (16.5  0.1%)  3.7%)  f o r a l l s p e c i e s are compared  Epilobium angustifolium contained  and  Alectoria  sarmentosa  s i m i l a r t o t h a t observed (e.g. V a c c i n i u m  spp.)  f o r dry matter  significantly  significantly  crude p r o t e i n than o t h e r s p e c i e s examined.  The  sta-  less  (1.9  general trend  ± was  content; c l o s e l y r e l a t e d p l a n t s  and p l a n t s of s i m i l a r s t r u c t u r e (e.g. c o n i f e r s and  shrubs) c o n t a i n e d s i m i l a r l e v e l s o f crude p r o t e i n .  Dry M a t t e r D i g e s t i b i l i t y  Annual p a t t e r n s o f DDM (Table  3-1).  values  f o r the  (DDM)  i n v i t r o v a r i e d among f o r a g e types and by season  R e s u l t s d i s c u s s e d here are individual  those  deer c o l l e c t e d  f o r mean DDM  since  each month i n most i n s t a n c e s  were not s t a t i s t i c a l l y d i f f e r e n t .  Alectoria  sarmentosa was  gestible  an  b a s i s , w h i l e f e r n s had  forage  l o w e s t DDM  (72.5  ± 4.5%)  (31.6 ± 1.8%).  on  annual  On an annual b a s i s , DDM  l i c h e n s , f o r b s , c o n i f e r s , shrubs and f e r n s . different forbs,  from each o t h e r  which  were  not  types  are  types  i n s p r i n g than  significant  presented  (p < 0.05)  different.  i n Table i n other  d i f f e r e n c e s occurred  the most d i -  decreased  the  i n the o r d e r  A l l t y p e s were s i g n i f i c a n t l y  w i t h the e x c e p t i o n o f l i c h e n s and Within-season  3-1.  DDM  comparisons  of  Fewer d i f f e r e n c e s o c c u r r e d  seasons,  but  each season.  a number o f The  forage between  statistically  relative  ranking  of  106  DDM,  with lichens highest and  a l l seasons with one exception.  ferns lowest remained consistent through A. sarmentosa was much lower in DDM in  spring (48.2 ± 2.3%) than its mean annual DDM  DDM  of conifers, shrubs and  seasons (Table 3-2).  (72.5 ± 4.5%).  forbs did not differ significantly between  Lichens were significantly lower in DDM  in spring  than in summer or fall-winter and ferns were significantly lower in spring than in fall-winter. This observation was was  somewhat unexpected since DDM  highest in spring or summer in the other types.  sarmentosa the low DDM  in spring was  In the case of A.  due to a change in the capacity of  the rumen microbes to digest i t , since a standard A. sarmentosa sample tested each month also was period.  The  digested to a much lesser extent during this  reasons for the low DDM  in ferns in spring are not clear,  since foliage tested consisted entirely of new tissue. Levels of lignin were high in ferns in spring; this may discussed  explain the low DDM  and will be  further in conjunction with the fibre components.  of annual DDM  levels in forage types from forested and  Comparison  cutover  areas  (Table 3-2) indicated that in a l l cases, plants from cutovers were higher in DDM but the differences were not statistically significant (p < 0.05). In only one instance (ferns in spring) was a seasonal DDM value higher in forested than in cutover areas.  Mean DDM  This difference also was not significant.  of individual forage species are listed in Table 3-3.  Gaultheria  shallon did not differ between seasons, except in cutovers  when f a l l -  winter digestibility was higher than in spring and summer. Both Vaccinium alaskaense and V. parvifolium were significantly more digestible in spring than in fall-winter, except that V. parvifolium collected in cutover areas  107  was not different in DDM between seasons.  Pseudotsuga menziesii and Thuja  plicata did not differ seasonally in DDM i n either forested areas or cutovers but Tsuga heterophylla from forested areas was higher in DDM during fall-winter  than  spring.  Alectoria  sarmentosa was  collected  only in  forested areas and was lower i n DDM in spring than in the other seasons. DDM  of Epilobium angustifolium (collected only in cutovers) was not dif-  ferent during the seasons, but sample sizes were small since the species was  not available from November to May.  nificantly in DDM  Blechnum spicant differed sig-  between spring and fall-winter, with highest levels in  the latter period i n both forested and cutover areas. seasonal differences in DDM  There were no  of Polystichum munitum in either forested or  cutover areas.  DDM  of a l l three shrub species was higher in cutovers than in forested  areas throughout the year (Table 3-3).  These differences were s t a t i s t i -  cally significant only in fall-winter for Gaultheria shallon and Vaccinium parvifolium.  An exception was  G. shallon which was significantly more  digestible in timber i n summer.  Among conifer species, DDM was generally higher in cutovers than in forest throughout  the year as was  indicated in Table 3-3).  crude protein (statistical differences are  DDM of the fern species did not differ s i g n i f i -  cantly between forested areas and cutovers in any season, although the general tendency again was to higher levels in cutovers.  Individual species differences in DDM (Table 3-4).  were compared on an annual basis  Alectoria sarmentosa and Epilobium angustifolium were sub-  108  s t a n t i a l l y more d i g e s t i b l e than a l l other species. As was observed with both dry matter and crude p r o t e i n content, species of s i m i l a r s t r u c t u r e tended to have s i m i l a r d i g e s t i b i l i t i e s , with some exceptions as indicated i n Table  To  3-4.  summarize, the  species  exhibiting  the  highest  DDM  was  Alectoria  s a rmento s a,p rob ably the r e s u l t of i t s containing d i f f e r i n g types of struct u r a l carbohydrates (e.g. hemicellulose rather than c e l l u l o s e , Hale and  1961)  less l i g n i n (Scotter 1965), than other forage species examined.  A.  sarmentosa was digested i n v i t r o at a low l e v e l i n s p r i n g , apparently the r e s u l t of changes i n the capacity of rumen microbes to d i g e s t l i c h e n at t h i s time.  Among the forage types, ferns were lowest i n DDM  with the  lowest seasonal l e v e l s occurring when only new growth on a c t i v e l y growing plants was  sampled. I t i s l i k e l y t h i s reduced DDM  proportions of l i g n i n at t h i s time.  i s the r e s u l t of high  Contrary to other forage types, ferns  exhibited highest l i g n i n contents i n spring (Table 3-7).  Seasonal d i f f e r e n c e s i n DDM r e l a t e d to the presence  d i d not occur i n c o n i f e r s and shrubs, probably  of greater amounts of f i b r o u s s t r u c t u r a l t i s s u e  i n these forage types than i n herbaceous p l a n t s , except f e r n s , which cont a i n higher than expected l e v e l s of f i b r e .  Broadly c o n s i s t e n t , but n o n s i g n i f i c a n t l y higher l e v e l s of DDM forage types from cutovers compared to forested areas.  occurred i n  Einarsen (1946)  also observed that forage q u a l i t y (protein content) of plants from cutovers was  higher and  a t t r i b u t e d i t to increased s u n l i g h t and n u t r i e n t  supplies i n s l a s h areas.  109  Ferns and lichens excepted, higher digestibilities occurred in spring, the  time when structural and fibrous cell components were present in  lowest amounts and crude protein levels were greatest.  Rates of Dry Matter Digestibility  The rate at which a forage species is digested, as well as the extent to which i t i s digested determines i t s value to a ruminant. are  Species which  slowly digested may leave the rumen prior to being fully broken down  by rumen microbes or lead to rumen compaction. Three trials were run to examine the rates of DDM for selected species and the influence of season of collection on this rate. of  Results are expressed in Table 3-5 in terms  percent of maximum 48-hour digestibility occurring at each 12-hour  interval from the beginning of the t r i a l .  Sample sizes were too small to  permit statistical comparisons of digestibility rates, but certain trends are  obvious.  dormant state.  Both March t r i a l s were conducted on plant species in the For a l l species but Alectoria  sarmentosa an apparent  asymptote in the f i r s t 48-hour stage of digestibility was attained by 24 to 36 hours. Digestion of A. sarmentosa increased more linearly through the  36-hour period; only 25% of the value attained at 48 hours was  achieved after 12 hours, 46% after 24 hours and 91% after 36 hours. Rumen turnover times are not known for coastal black-tailed deer in the wild.  However, studies with white-tailed deer (Qdocoileus virginianus)  indicate rumen retention times ranging from 14-19 hours for a succulent diet (Mautz and Petrides 1971) to 33 hours for a fibrous hay diet (Cowan 1970).  If this range of rumen turnover time is applicable to deer in  this study, A. sarmentosa may be of less value than the other species,  T a b l e 3-5.  Rates o f in vitro  d i g e s t i b i l i t y of s e l e c t e d f o r a g e s p e c i e s .  P e r c e n t o f Maximum Dry M a t t e r D i g e s t i b i l i t y Occurring i n : Trial Date  Species - A r e a  12 Hours  2  24 Hours  36 Hours  48-Hour Observed Digestibility (Actual)  1  2-Stag Method  March 5  Gaultheria shallon - F Vaocinium alaskaense - F Thuja plioata - F Alectoria sarmentosa - F  76.0" 66.0 88.0 25.0  88.0 89.0 88.0 46.0  100.0 89.0 100.0 91.0  17.3 26.7 43.8 60.6  33.0 34.5 52.5 80.0  March 19  Bleohnum spicant - C Vaocinium parvifolium Thuja plicata - C Thuja plicata - F  56.0 70.0 82.0 72.0  75.0 82.0 90.0 96.0  100.0 97.0 94.0 96.0  33.0 34.8 52.5 48.0  41.5 45.5 57.0 52.5  76.0 80.0 86.0 83.0 77.0  96.0 100.0 100.0 93.0 100.0  100.0 100.0 100.0 100.0 100.0  58.1 63.1 47.3 75.7 42.6  55.0 65.0 48.0 77.5 37.0  June  14  In vitro  1  s  Vaocinium parvifolium - C V. alaskaense - C Pteridium aqualinum - C Sambuous racemosa - C Pseudotsuga menziesii - C  d i g e s t i b i l i t y a f t e r 48 hours i n c u b a t i o n i n rumen f l u i d .  A r e a of c o l l e c t i o n :  2  In  3  F = F o r e s t e d , C = Cutover.  vitro d i g e s t i b i l i t y by T i l l e y and T e r r y method - 48 hours i n c u b a t i o n i n rumen 48 hours i n c u b a t i o n i n A c i d - p e p s i n s o l u t i o n .  ^ V a l u e s a r e means o f two r e p l i c a t e 5  - C  Plants collected  i n May,  samples.  deer c o l l e c t e d  i n June.  fluid,  Ill  since i t would leave the rumen prior to being fully digested. al.  Person et  (1975) observed a rumen retention time in reindeer of almost five  days for a mixed lichen diet and suggested an in vitro incubation period longer than 48 hours was  required to accurately assess DDM  of lichens.  This was not the case with A. sarmentosa, which is digested more slowly than other species examined but s t i l l reaches 90% of 48-hour digestibility in 36 hours. Plant phenological stage affects digestibility rates as can be seen when the March trials are compared with those in June, which used new  growth tissue of the current year. Relative digestion rate was about  10% higher in the June t r i a l than in the March trials at comparable time periods.  As total digestibility of V. alaskaense and V. parvifolium was  approximately twice as high in June as in March, absolute digestion rate was much greater in June. June, DDM  Also of interest is the observation that, in  of most species was  as complete after a 48-hour  fermentation  period in rumen fluid as in a 48-hour fermentation period plus a 48-hour acid-pepsin  digestion.  sistently higher observations  In March, the two-stage digestion produced con-  levels of DDM  than the  48-hour fermentation.  These  suggest that rumen microorganisms are better able to digest  both carbohydrate and proteins in the tested forage species in June.  In  dormant plants, protein digestion in acid-pepsin substantially contributes to total digestibility.  These seasonal  differences are probably asso-  ciated with higher levels of fibre and lower nutrient contents of dormant plants collected in March.  112  Fibre Components of Forage Plants  The Van Soest (1963) system of analysis breaks feed down into components which relate to their relative digestibility by ruminants. of  The advantages  the Van Soest system over traditional crude fibre measurement were j  discussed earlier, as were components of fibre. detergent fibre  To summarize: Neutral-  (NDF) represents the cell wall contents, acid-detergent  fibre makes up the combined ligno-cellulose portion of the cell wall and acid-detergent lignin (ADL) is the portion of the cell wall composed of lignin.  The difference 1-NDF  represents that portion of the feed asso-  ciated with digestible cell contents (i.e. the highly digestible sugars, starches and some proteins in forage), NDF-ADF provides a measure of the hemicellulose content, which is digestible, and ADF-ADL indicates the cellulose content separately from lignin, both of which are relatively indigestible.  Fibre components of forage types are presented in Table  3-6 and 3-7. NDF and Cell Contents  Statistical  comparisons  of cell  contents and NDF  are the same, since  variances are the same (cell contents = 1 - NDF) thus these two measures are treated together.  Significant annual differences in NDF and cell contents occurred between a l l forage types except lichens and forbs, which were both low in NDF and correspondingly high in cell contents.  NDF  levels in increasing order  and cell contents in decreasing order in forage types were lichens, forbs, conifers, shrubs and ferns (Table 3-6).  Table 3-6. S t a t i s t i c a l comparisons of c e l l contents and neutral-detergent f i b r e of forage c o l l e c t e d from f o r e s t e d (F) and cutover (C) areas i n d i f f e r e n t seasons. Comparisons are made between forage types f o r each season and a n n u a l l y . Neutral-Detergent Fibre  C e l l Contents Season Forage Type  of oven dry F  C  F+C  Shrubs  6  6  12  2  53.3 (13.8)  63. 2 ( 7.5)  58.3 (11.8)  46.7 (13.8)  36.7 ( 7.5)  41.7 (11.8)  Conifer  6  6  12  58. 8 ( 6.6)  65.7 • ( 8.3)  62. 2 ( 8.0)  41.2 ( 6.6)  34. 3 ( 8.3)  37.8 ( 8.0)  Lichen  2  -  2  83. 0 ( 1.7)  -  -  17.0 ( 1.7)  -  -  Forbs  -  2  2  -  87. 2 ( 6.4)  -  -  12.8 ( 6.4)  -  Ferns  4  A  8  44. 7 (15.5)  50.l ( 9.0)  47.4 (12.1)  55. 2 (15.5)  49.9° ( 9.0)  52. 6 (12.1)  Shrubs  8  8  16  45.9 ( 6.6)  56.3 ( 4.9)  51. l ( 7.8)  54. l ( 6.6)  43.7 ( 4.9)  48.9 ( 7.8)  Conifer  7  7  14  60. 5 ( 6.7)  61.5 ( 4.2)  61.0 ( 5.4)  39.5 ( 6.7)  38.5 ( 4.2)  39.0 ( 5.4)  Lichen  3  -  3  77.2° ( 8.3)  -  -  22.8 ( 8.3)  -  -  Forbs  -  2  2  -  73.8 ( 8.4)  -  -  26.2 ( 8.4)  -  Ferns  4  4  8  33.3 ( 4.6)  44.5 (13.0)  38.9 (10.8)  55.5 (13.0)  61. l (10.8)  F  C  F+C  F  C  F+C  Spring a  a  b  a  a  b  a  c  a  a  a  a  b  C  a  a  b  a  a  a  C  Summer a  b  a  b  C  d  d  a  b  a  b  C  d  a  a  b  66.7 ( A.6) d  C  a  b  d  I  T a b l e 3-6.  continued. Neutral-Detergent Fibre  C e l l Contents ( P e r c e n t o f oven d r y w e i g h t )  Season Forage Type  F+C  F  C  F+C  F+C  Fall-Winter Shrubs  17  18  35  45.1" ( 5.4)  ad 50.2 ( 7.7)  Conifer  18  18  36  58. 6 ( 4.5)  61.0 ( 4.0)  b  54.9" ( 5.4)  ad 49.7 ( 7.7)  52.3" ( 7.1).  59. 8  41.4 ( 4.5)  39.0 ( 4.0)  40. 2 ( 4.4)  C  (  b  4.4)  b  c  Lichen  C  B  24.3°  75.7 ( 6.3)  (  6.3)  abd 55.8 ( -.)  Forbs Ferns  47.7 ( 7.1)  abd 44.2 ( - )  10  10  20  38.1" ( 9.3)  47.3 (10.5)  42.7 (10.7)  .34  32  63  46.9 ( 8.2)  54 . 2 ( 8.5)  (  59. l (5.3)  62,. 0 ( 5..2)  60.5 ( 5.4)  40.9 ( 5.3)  77.4 ( 6.5)  22.6° ( 6.5)  75.,5°' (14.•Q)  75.5 (14.0)  _  47..3 '.-(10. 3)  42.9 (U.l)  d  61.9" ( 9.3)  52.7 (10.5)  57.3" (10.7)  45.8 . ( 8.5)  49.4 ( 9.1)  38. 0 ( 5.2)  39.4 (5.4)  d  All-year Shrubs  Conifer  34  31  62  Lichen  12  1  11  3  b  Forbs  Ferns  •  5  20 .  18  -  'N v a r i e s depending o f t h e samples V a l u e s i n a column by a n a l y s i s o f  2  ,  5  36  b  77.4 6.5) C  (  50. 6  a  a  9.1) b  C  —  38.5 (10.4)  .  d  d  C  d  53.l 8.2) a  (  a  b  61.5 (10.4) d  b  -  b  22.6  _  (  C  6.5)  24.5 (14.0) C  24. 5° (14.0)  52.7  d  57. l (11.1)  (10.3)  on f i b r e c h a r a c t e r i s t i c , s i n c e ADL and c e l l u l o s e were determined on o n l y about 50 p e r c e n t w h i l e o t h e r a n a l y s e s t r e a t e d a l l samples. w i t h a common s u p e r s c r i p t l e t t e r ( , b, c) a r e not d i f f e r e n t a t p < 0.05 l e v e l as d e t e r m i n e d v a r i a n c e and S c h e f f e s t e s t . a  A  d  3-7.  Table  S t a t i s t i c a l c o m p a r i s o n s o f a c i d - d e t e r g e n t f i b r e , a c i d - d e t e r g e n t l i g n i n , c e l l u l o s e , and h e m i c e l l u l o s e c o n t e n t o f f o r a g e c o l l e c t e d f r o m f o r e s t e d ( F ) and c u t o v e r (C) a r e a s i n d i f f e r e n t seasons. C o m p a r i s o n s a r e made between f o r a g e t y p e s f o r e a c h s e a s o n and a n n u a l l y .  Ac i d - D e t e r g e n t  Acid-Detergent  N  ijjj>re  Lignin  F  C  F+C  1 C  Shrubs  6  6  12  2  41.1 (10.3)  32 . 0 ( 6 • 3)  36. 5 ( 9.5)  a  16.8 ( 3.6)  14.4 ( 2.9)  15. 6 ( 3.4)  3  24. 3 (10.2)  17 ( 4 • 2)  Conifer  6  6  12  35. 5 (10.2)  31 . 9 (13 .8)  33.7 ( 9.7)  20.9 ( 2.0)  15.5 ( 3.2)  18. 2 ( 3.8)  14. 6 ( 2.2)  16 .4 (12 • 6)  Lichen  2  -  -  3.0° ( 1.4)  -  -  i.o ( 1.4)  -  -  Season Forage Type  — F  F+C  Cellulose  Hemicellulose  ( p e r c e n t o f ov en d r y w e i g h t ) F  C  F+C  F  C  F+C  F  C  F+C  Spring a  a  2  4.0 (  a  a  b  a  - )  a  ab  a  a  a  a  b  ^abc  20 . 9 5.6 ( 8 • 2) (11.9)  4.8 ( 8 • 0)  5. 2 ( 9 • 7)  , abc  15 . 5 ( 8 .7)  2 .5 (11 .6)  4. l ( 8 • 3)  a b  a C  a  5.7 ( 3.4) a  a  a  a  a  13.0 ( 1.7)  c  a  11 . l ( 4 .4)  -  52. 3 (2.8)  49 .6° ( 8,.9)  51. 0 ( 6.3)  24. 9 ( 9.3)  b  21.7° ( 3.7)  23.3° ( 6.8)  27.3 ( 8.8)  27 .9 ( 9 .7)  27, ,6 ( 8,.6)  2.9 (16.4)  0 .25 ( 4 .2)  16  41.4 ( 8.4)  34. ,7 (11. .6)  38. l (10.4)  a  22. 3 ( 4.8)  a  15. 3 ( 3.1)  a  18.8 ( 5.3)  19. 2 ( 9.1)  19 . 5 (11. .8)  19. ,3 (10. .2)  12. 7 (11.6)  8. 9 ( 9,• 8)  10. ,8 (10. .6)  7  14  34.4 ( 5.4)  32. ,o ( 7..5)  33. 2 ( 6.4)  22. 6 ( 2.4)  19. 2 ( 4.5)  20.9 ( 3.9)  11.9 ( 5.6)  12. .8 ( 5,.9)  12. ,3 ( 5. 6)  5.0 ( 6.4)  6,.6 ( 7,• 0)  5. 8 ( 6. 5)  3  -  3  15. 5 (10.6)  -  3.3 ( 0.2)  -  .. -  12. 2 (10.8)  Forbs  -  2  2  -  -  3.4 ( 1.6)  -  Ferns  4  4  8  19.7 (10.1)  22.7 ( 7.7)  Forbs  -  2  2  Ferns  4  4  8  Shrubs  8  8  Conifer  7  Lichen  b  -  C  6.0 ( 2.9) b  C  b  a  C  1. 6 ( 2 • 0) a  5. l ( 1 • 5)  -  b  a  a  1..6 (11. .1) a  Summer a  a  a  a  b  14. ,9 ( 4.• 1.)  a  b  b  -  64. 6 (11.8)  C  52. 1 (10. 3)  C  a  58. 4 (12.2)  C  a  b  25.8 ( 3.4) a  a  a  a  a  a  a  a  a  b  a  b  a  11. .3 (12. .6)  a  38.8 ( 9.4)  a  a  a  11. .5 ( 2..5)  -  a  7.3 (18.8)  a  3  a  32. ,4 ( 4..6) b  a  -  35.  b  C  ( 7. 7)  2.1 (16.3) a  .3.,4 2. 7 (10. • 2) (12. 6) a  a  T a b l e 3-7. Ac i d - D e t e r g e n t Fibre Season Forage Type  continued.  Acid-Detergent Lignin  Cellulose  Hemicellulose  (percent of oven dry weight) F  F+C  F+C  F  C  F+C  F  F+C  F+C  Fall-Winter Shrubs  17  18  35  42. 3 •( 5.5)  38.9 ( 7.1)  40 .6 19. l ( 6,.5)'.' ( 3,2)  17. 6 ( 4.7)  18 .4 , 26.3 ( 3.6) ( 3.9)  22 .2 ( 4 .8)  aD ' 24 .2 ( 4.5)  Conifer  18  18  36  34. 3 (2.6)  32. 3 ( 6.8)  33,. 3 ( 5. .2)  15. l ( 4.7)  17 .6 ( 4,• >  20 . 9 (15 . 6 )  18 .2 (10 .9)  Lichen  6  a  b  a  b  C  -  10  10  20  20.l ( 2.1) a  a  a  a  a  4  1.6 0.2)  21.3  b  15.5 ( 1.1) b  4. 8  (  _  a  -• )  1  22 . 9  a  -- )  (  21 .3 ( 8.3)  (  16.5 (11. 6)  15 .2 ( 8 .6)  ,bd 6. ( 4.4)  ce 6.3 ( 8.4)  14.4* (11.4)  19.7 ( 4.5)  15. 7 ( 3.7)  (  34. 5 ( 3,4)  32.2 ( 8.3)  33. 3 ( 6 . 4)  21.3 ( 2.3)  16.7 ( 4.4)  19. 0 ( 4 . 2)  13. 9 ( 3.8)  2.7 1.0)  6.3 " ( 8.4)  d  a  6 .9  b  ( 4 .4)  1)  19. 7 ( 8.1)  39. 2 ( 8.2)  a  8 .•  22.8  36. 6 ( 8.5)  18.,5 ( 7.9)  11 .7 ( 4 • 8)  18 . 4 °  13. ( 5,•  41. 9 ( 7.1)  a  B  b  bd 30 ( 5.9)  19. 5 ( 9.2)  :  7. l 6 ;6 ( 3• 8) '( 5 • > -  28., o ( 6. .4)  17.5 ( 7.6) a  <..*  a  a  32.6 ( 5.0)  45.3 ( 8.3) d  a  10 . 8 •4) . ( 5  12 .6  (  (  42. 6 (10.4) a  a  16,,5  47.8 ( 5.2) d  a  C  —  - )  a  2.7 ( 0.3)  B  (  ( Ferns  b  a  -  5.9 (5.6)  Forbs  a  a  3  ^ac 9  -- )  id, (  >  C  j ab  6,.4)  11., 9 ( 6. 3) a  All-year Shrubs  34  Conifer  34  Lichen  12  32  31  63  62  a  b  11 (  !  20  18  N v a r i e s depending of the samples V a l u e s i n a column by a n a l y s i s o f  36  b  8.2 7.8)  Forbs  Ferns  a  •52. 3" ( 9.2)  a  b  8.2 " 7.8) 1  ( i4. r ( 5.1)  14.7° ( 5.1)  46.3 (10.4)  49.4 (10.2)  d  d  a b  a C  a C  2, 7 ( 1.0)  be 22.8 ( 7.6)  17.  a  7  ac  4 . 5) a  U  ( 4.8° ( 2.1)  4.8 (2.1)  20.3° ( 7.4)  21.5° ( 7.5)  (  a  8.4) b  a  a b  1  b  32.9 ( 8.7)  a  b  9.9" ( 5.1)  be 9.9 ( 5.1)  29.4 ( 6.9)  31. 2 ( 7.9)  C  d  11..3 8 . 6) a  cd 3.0 ( 8.9)  9.,2 ( 7. • 2)  10. 2 ( 7.9)  5. 8 ( 7.0)  6. l ( 5.8)  a  a  a  b  ade 14.4 (11.4) 9. 8" (10. S)  abef ;•. 9.8 (10.8)  6. 4 ( 7.9)  5.3 ( 8.3)  on f i b r e c h a r a c t e r i s t i c s , s i n c e ADL and c e l l u l o s e were determined on only about 50 percent w h i l e o t h e r a n a l y s e s t r e a t e d a l l samples. w i t h a common s u p e r s c r i p t l e t t e r (a, b, c) a r e not d i f f e r e n t at p < 0.05 l e v e l as determined v a r i a n c e and S c h e f f e ' s t e s t .  a  cdf  117  When compared seasonally, the woody types, shrubs and conifers did not differ from each other during spring i n cell content or NDF nor did forbs and lichens (Table 3-6). In summer, a l l types differed in both measures except forbs and lichens and in fall-winter, a l l types differed from each other except that forbs were intermediate in value and differed only from lichens.  Within a forage type, NDF and cell contents generally were not s i g n i f i cantly different between seasons (Table 3-8).  Plants collected in spring  were highest in cell content and lowest in NDF but not significantly so, except in shrubs collected in timber in which spring levels were different from levels i n fall-winter but not in summer. The lack of statistical differences between seasonal levels of fibre may in part be a function of the way seasons were defined.  Changes i n fibre levels i n some species  appear to precede changes in crude protein and DDM (Figures 3-6 to 3-8) and external phenologic differences. Thus, NDF levels in the latter part of the fall-winter period begin to approach spring levels and i f spring had included April as well as May and June then significant between-season differences may have been observed. Since seasons were defined primarily as a function of when growth was initiated in most species, extension of the spring season to include April would obscure some of the seasonal variations observed in crude protein and DDM which were associated with visible initiation of growth.  Annual levels of cell contents were significantly higher i n a l l forage types collected i n cutovers than in forested areas and NDF was thus consistently higher  in plants from forest.  Apparently levels of soluble  Table 3-8.  S t a t i s t i c a l comparisons of c e l l components of forage c o l l e c t e d from forested (F) and cutover (C) areas i n d i f f e r e n t seasons. Comparisons are made between seasons and areas of c o l l e c t i o n for each forage type. Neutral-Detergent Fibre  i  N  C e l l Contents  >  C  F+C  6 ( 6)  6 ( 6)  12 (12)  8 ( 8)  8 ( 8)  16 (16)  Fall-Winter  17 ( 5)  18 ( 6)  35 (11)  Annual  31 (20)  32 (20)  63 (40)  ?  F  Acid-Detergent Fibre  ( Percent of oven dry weight ) F+C F C F+C  _C  F  C  Shrubs Spring  Summer  53.,3 (13. .8)  a  45. 9 ( 6. .6)  3  45. 1 ( 5. •4)  b  a  3 b  63..3 ( 7. .5)  2  58..3 (11. .8)  a  56.. 3++ ( 4. ,9)  50.,3++ ( 7. .7)  b  46. 9 ( 8.2)  51.,1 ( 7..3)  3  b  Shrubs,  a b  5 4 ..1++ ( 6. .6)  3  36,.8 .5) ( 7.  a  43..7 ( 4. .9)  b  41 .7 (11 • 8) 48 .9  b  50.,6 ( 9. .1)  53.,1++ ( 8.2)  45.,8 ( 8.6)  49 .4 ( 9• 1)  54.,2++ ( 8.6)  49..7 ( 7. .7)  41..4 ( 8. .4)  a  42..3++ ( 5. .5)  a  a  b  54.,9++ ( 5. ,4)  a  ( 7 • 8)  b  47.J ( 7. ,1)  41,.1 (10. • 3)  3  .3 ( 7.1) 5 2  a  41..9++ ( 7. ,1)  Cellulose  0  a  34..8 (11. .7)  a  38..9 ( 7. • 1)  a  36,.5  .5) ( 9. 38..1 (10, .4)  40..6 .5) ( 6,  36.,6 ( 8.5)  39.,2 ( 8. •2)  Hemicellulose  ( Percent of oven dry weight ) F C F+C  F+C  32..0 ( 6. • 3)  F  C  F+C  continued  Spring  16..8 .7) ( 3.  a  22. ,3++ ( 4. .8)  Summer  Fall-Winter  Annual  a  b  Ac id-De tergent Lignin  I  46..7 (13. .8)  a  b  a b  1 9 . ,1 .2) ( 3. 19..7++ ( 4. ,5)  a  !4.,4  l 5 . .6 .4) ( 3.  a  ( 2. .<)) 15., 3 ,1) ( 3.  a  a  17..6 ,7) ( 4. 15.,7  ,7) ( 3.  18.,8 ( 5. .3)  a  l 8 ..4  24..3 (10, .2)  a  19.,2 ( 9. .1)  a  ( 3.9)  26..3+ • 6) ( 3.  17. 7 ( 4. •5)  22.,8 ( 8.4)  a  a  l7.5 ( 4.2)  a  19.5  a  a  a  (11.8) 22.2 ( 4.8)  a  19.7 ( 8.1)  20,.9 ( 8, .1) 19,.3 (10, .2)  24..2 ( 4, .5)  a  21..3 ( 8. .3)  5 ,.6 (11. .9)  ( 8.0)  12, .7 (11 • , 6)  8,.9 ( 9, .9)  a  a  i 2 ..6+ ( 4, • 4)  a  11.,2 ( 8. .6)  a  4,.8  a  a  i o ..8  5.2 ( 9.7) a  ab  10.8 (10.6)  ( 5. .1)  11.7 ( 4.8)  9..2 ( 7. .2)  10.2 ( 7.9)  b  Table 3-8.  continued.. Neutral-Detergent Fibre  C e l l Contents F  C  F+C  F  ( Percent of oven dry weight )  C  F+C  F  C  Acid-Detergent Fibre F+C  F  C  F+C  Conifers Spring  6 6 12 ( 6) ( 6) (12)  Summer  7 7 14 ( 7) ( 7) (14)  Fall-Winter  18 18 36 ( 6) ( 6) (12)  Annual  31 (19)  31 (19)  58. .8 ( 6. .6)  a  a  61.5 ( 4.2)  a  61.0++ ( 4.0)  a  60. ,5 ( 6. .7)  a  58. .6 ( 4. .5)  a  a  a  62 (38)  65.7+ ( 8.3)  62.2 ( 8.0)  3  59. 1 ( 5.3)  61.0 ( 5.4) 59.8 ( 4.4)  62.0++ ( 5.2)  60.5 ( 5.4)  S  41.2+ ( 6.6)  a  39.5 ( 6.7)  a  41.4++ ( 4.5)  a  a  a  40.9++ ( 5.3)  Acid-Detergent Lignin  I Conifers,  a  38.5 ( 4.2)  a  39.0 ( 4.0)  a  38.0 ( 5.2)  37. .8 ( 8, • 0)  a  39. .0 ( 5. • 4)  a  40. .2 ( 4. ,4)  a  39.,4 ( 5.4)  35,.5 ( 3. • 2)  32. .0 ( 7. .5)  a  32. .3 .8) ( 6.  a  a  34. .3 ( 2.6)  a  34.,5 ( 3.4)  32..2 ( 8. .3)  3 3 .7 ( 9• 7)  3 3 .2 ( 6• 4) 3 3 .3 ( 5• 2)  33 .4 ( 5.3)  Hemicellulose  ( Percent of oven dry weight ) F C F+C  F+C  a  34. .4 ( 5. .4)  Cellulose  C  31..9 (13,• 8)  a  F  C  F+C  continued  Spring  2 0 . 9++ ( 2.0)  a  2 2 . 6+ ( 2.4)  a  2 0 . 2++ ( 2.1)  a  a  Summer  a  Fall-Winter.  a  Annual  34.3 ( 8.3)  21. 3++ ( 2.3)  15. 5 ( 3.2)  19. 2 ( 4.5) 1 5 . .1 ( 4.8)  16. 7 ( 4.4)  ab  18.2 ( 3.8) 20.9 ( 3.9)  a  17.6 ( 4.4)  b  19.0 ( 4.2)  14. .6 ( 2. .3)  a  a  H  .  16.4 (12.6)  a  l 5 . .5 ( 8. .7)  5 .7 ( 3, .4)  2 ,.5 (11 .6)  4.1 ( 8.3)  12. .3 ( 5. .6)  5 ..0 ( 6, .4)  6 ,.6 ( 7. .0)  5.8 ( 6.5)  18. ,2 (10..9)  7 ..1 ( 3. .8)  6 ..6 ( 5. .1)  6.9 ( 4.4)  15. 2 ( 8.6)  6..4 ( 4. .4)  5..8 ( 7. • 1)  6.1 ( 5.8)  i l . .9 ( 5. .6)  a  l2.8 ( 5.9)  3  15. ,5 ( 1. • 1)  a  20.9 (15.6)  a  a  13.,9 ( 3.8)  16.5 (11.6)  a  3  a  a  a  a  a  a  a  I—  I— 1  vO  Table 3-8.  continued. Neutral-Detergent Fibre  C e l l Contents  F  +  C  F  /  ( Percent of oven dry weight F+C F C  C  Acid-Detergent Fibre  ) F+C  F  C  . F+C  Lichens Spring  2 ( 2)  Summer  83.0 ( 1.7)  a  3 ( 3)  77.2 ( 8.3)  a  6 ( 6) Annual  l7.0 ( 1.7)  a  22.8 ( 8.3)  75.7 ( 6.3)  77.5 ( 6.5)  4.0 - )  15.5 (10.6)  a  24.3 ( 6.3)  5.9 ( 5.6)  22.6 ( 6.5)  8.2 ( 7.8)  a  Acid-Detergent Lignin  a  Cellulose  Hemicellulose  -( Percent of oven dry weight )F C F+C  F+C Lichens,  (  a  a  11 ( 7)  a  F+C  continued  Spring  Summer  3.0 ( 1.4)  a  3  3.3 ( 0.2) a  i.o  ( 1.4)  13, .0 .7) ( 1,  12.2 (11.0)  7,.3 (18,.8)  a  Fall-Winter  1.6 •( 0.2)  2.7 ( 0.3)  Annual  2.7 ( 1.0)  6.3 ( 8.4)  3  a  a  a  18. ,4 ( 8. ,1)  S  14.,4 (11. 4)  Table 3-8.  continued. Neutral-Detergent Fibre  C e l l Contents  F  C  F+C  F  C  ( Percent of oven dry weight ) F+C . F C F+C  Acid-Detergent Fibre :  F  C  F+C  Forbs Spring  2 ( 2)  a  Summer  2 ( 2)  a  Fall-Winter  1 ( 1)  a  Annual  5 ( 5)  87.2 ( 6.4)  a  73.8 ( 8.5)  3  55.8 ( - )  a  F  C  U.2 ( 4.4)  a  26.2 ( 8.5)  l4.9 ( 4.1)  a  44.2 ( - )  75.6 (14.0)  Ac id-Detergent Lignin  Forbs,  l2.8 ( 6.4)  21.3 ( - )  a  24.5 (14.0)  14.7 ( 5.1)  Cellulose  F+C  ( Percent of oven dry weight ) F C F+C  Hemicellulose  I-  C  continued  Spring  6.1 ( 2.9)  Summer  3.4 ( 1.6)  Fall-Winter  4.9 ( - )  Annual  4.8 ( 2.1)  5.1 ( 1.5)  a  a  a  1.7 ( 2.1)  a  ab  11.5 ( 2.5) !6.5 ( - )  b  9.9 ( 5.1)  a  a  ll.3 (12,6) 22.9 ( - )  a  9.8 (10.9)  F+C  Table 3-8.  N^  Neutral-Detergent Fibre  C e l l Contents  C  F  F+C  Acid-Detergent Fibre  ( P e r c e n t of oven d r y weight )  :  F  continued.  C  F  F+C  C  F  F+C  . C  F+C  Ferns Spring  4 4 ( 4) ( 4)  8 ( 8)  a  44. 8 (15. 5)  a  Summer  4 ( 4)  4 ( 4)  8 ( 8)  a  33. 3 ( 4.6)  a  Fall-Winter  11 ( 4)  10 ( 4)  21 ( 8)  a  38. 1 ( 9.3)  a  Annual  18 (12)  18 (12)  36 (24)  38. 5 (10. 4)  50.1 ( 9.0)  a  44.5+ (13.0)  a  47.3++ (10.5)  a  47.3++ (10.3)  47. ,4 (12,.1)  a  38. .9 (10,• 8) 4 2 . ,7 (10. .7) 42. ,9 (11..1)  Acid-Detergent Lignin  5 5 , ,3 (15.• 5)  a  a  66. .7+ ( 4, .6)  a  a  6 1 . ,9++ ( 9. .3)  a  61. ,5++ (10. • 4)  5 0 . .0 ( 9. • 0)  a  5 5 . .5 (13..0) 5 2 . ,7 (10. .5)  5 2 . .6 (12..1)  a  a  6 1 . ,1 (10. ,8)  a  5 7 . .3 (10. ,7)  52. .7 (10. .3)  57. ,1 (11..1)'  52, .3 ( 2. • 8)  a  4 9 . .6 .9) ( 8.  b  64, .6 (11,.8)  a  5 2 . .1 (10. .3)  a  5 8 . .4 (12..2)  a  47, .8+ .2) ( 5,  a  4 2 . ,6 (10. ,4)  b  4 5 , .3 ( 8. .3)  52. ,3 ,2) ( 9.  Cellulose  a b  46. .3 (10. ,4)  5 1 . .0 ( 6, .3)  49, .4 (10. .1)  Hemicellulose  ( P e r c e n t o f oven d r y weight )  • Ferns,  I  F  F+C  C  F+C  C  _F  • F+C  continued  Spring  a  Summer  a  Fall-Winter  3  Annual  C  25. 0 ( 9.3)  a  21. 7 ( 3.7)  25. 7 ( 3.4)  a  l9. 7 (10. 1)  a  17. 6 ( 7.7)  3  19. 5  a  22. 8 ( 7.6)  23. 3 ( 6.8)  a  22. 8 ( 7 . 7)  a  a  ( 9. 2)  18. 5 ( 7. 9)  20. 3 ( 7.5)  21. 5 ( 7.5)  27.4 ( 8.8)  a  38.8 ( 9.4)  3  32.6 ( 5.0)  a  a  32.9 ( 8.7)  27.9 ( 9.7)  a  32.4 ( 4.6)  b  28.0 ( 6.4)  29.5 ( 6.9)  3 b  27, .6 .6) ( 8,  3. 0 (16. 4)  3 5 , .6 .7) ( 7,  2. 1 (16. 3)  3 0 ,,3 ( 5. • 9) 31,,2 ( 7. .9)  o. 2 ( 4.2) a  3  a  a  3. 4 (10. 2)  a b  . l . .6 (11,.2) a  .  ( 5.9)  10. 1 ( 6.4)  l l . ,9 . ( 6..3)  3. 0 ( 8.9)  6. 4 ( 7 . 9)  5. 3 ( 8.3)  13. 7  b  N v a r i e s depending on f i b r e c h a r a c t e r i s t i c , s i n c e ADL and c e l l u l o s e were determined on o n l y about 50 p e r c e n t of t h e samples w h i l e o t h e r a n a l y s e s t r e a t e d a l l samples. V a l u e s i n a column w i t h a common s u p e r s c r i p t l e t t e r ( a , b, c) a r e n o t d i f f e r e n t a t p < 0.05 l e v e l as determined by a n a l y s i s o f v a r i a n c e and S c h e f f e ' s t e s t . S i g n i f i c a n t d i f f e r e n c e between f o r a g e c h a r a c t e r i s t i c i n f o r e s t e d and c u t o v e r areas i n d i c a t e d a s : + (p £ G.05) and ++ (p < 0.01). A n a l y s i s by t - t e s t . S i g n i f i c a n c e i n d i c a t o r i s b e s i d e the measure h a v i n g the g r e a t e r v a l u e , l  2  2 ,.7 (12,.6) a  b  123  protein, sugars and starches were higher in cutovers as a result of increased sunlight, better growing conditions and perhaps increased availability  of nutrients as reported by Einarsen (1946).  This occurs even  though dry matter content is higher in cutovers than forested areas for some forage types, suggesting solubles are more concentrated in plants from cutovers.  Annual levels of NDF between species within a forage type were compared statistically.  In shrubs,  Gaultheria shallon contained  significantly  less NDF and significantly more cell contents than Vaccinium alaskaense, probably due in part to i t s evergreen habit.  A l l seasonal G. shallon  samples included leaf tissue, which is usually lower in NDF than twig tissue (Short et a l . 1975).  NDF  was  higher and cell content lower in  Pseudotsuga menziesii than Tsuga heterophylla in a l l samples from forested areas.  P. menziesii twigs tend to be larger and more woody than those of  T. heterophylla and perhaps contributed a larger amount of fibrous mater i a l to the mixed twig-needle sample. Blechnum spicant was significantly lower in NDF and higher in cell contents than Polystichum munitum, which was obviously more fibrous as indicated by its greater dry matter content, the greater difficulty  in grinding i t for analyses as well as i t s greater  resistance to degradation during the winter.  Seasonally, levels of NDF and cell contents were statistically  different  between spring and fall-winter in most species, and in summer were not different  from the other two seasons  (Table 3-9).  highest during spring and lowest in fall-winter.  Cell contents were  This pattern reflects  the phenological stage and extent of tissue maturation in the plant as  Table 3-9.  S t a t i s t i c a l comparisons of c e l l components of forage species c o l l e c t e d i n forested (F) and cutover (C) areas at d i f f e r e n t seasons. Comparisons are made between seasons and areas of c o l l e c t i o n .  N  Neutral-Detergent Fibre  C e l l Contents  ( Percent of oven dry weight F  C  F  C  F+C  .  F  C  Acid-Detergent Fibre  ) F+C  F  C  F+C  Shrubs  Gaultheria  shallon  Spring  2  2  a  Summer  3  3  b  Fall-Winter  6  6  b  11  11  Annual  64.0' (10.4)  a  47.1 ( 8.1)  b  50.1 ( 3.0)  b  51.8 ( 8.2)  66.7 ( 7.2)  a  56.2+ ( 7.5)  b  56.8++ ( 5.6)  b  2  58.4++ ' ( 7.0)  65.4 ( 7.5)  a  51.7 ( 8.6)  b  53.4 ( 5.5)  b  55.1 ( 8.2)  Acid-Detergent Lignin  a  52.9+ ( 8.1)  a  49.9++ ( 3.0)  a  48.2++ ( 8.2)  34. 6 ( 7.5)  a  48. 3 ( 8.6)  a  46. 6 ( 5.5)  a  33.3 ( 7.2)  a  43.8 ( 7.5)  b  43.2 ( 5.8)  b  41.6 ( 7.0)  44. 9 ( 8.2)  C  a  35. .1 .0) ( 9.  a  37. ,3 ( 3. • 4)  a  a  39.3 ( 4.4)  a  40.8+ ( 2.6)  a  39.6+ ( 3.5)  34.6 ( 5.2) 37.2 ( 6.8)  39.1 ( 3.4) 37.8 ( 4.9)  35.,9 ( 5. .5)  Hemicellulose  ( Percent of oven dry weight F C F+C  F+C  32. .8 .9) ( 6.  36.5 ( 4.3)  Cellulose  . F  36.0 (10.4)  )F  C  F+C  Shrubs  Gaulthevia  shallon,  (continued)  Spring  a  Summer  a  Fall-Winter  a  Annual  l6.0 ( 1.0)  a  23.1 (5.5)  3  l7.7 ( 0.4)  a  19.5 (4.7)  16. .1 ( 3. .6)  a  18. ;0 • 9) ( 1.  a  ! 7 ., 1 ( 3. .1)  3  17.,2 • 4) ( 2.  l6. 0 ( 2.1)  a  20. 6 ( 4.6)  3  17. 4 ( 1.9)  a  18. 4 ( 3.8)  20. 5++ ( 3.3)  a  16. 2 ( 1.0)  a  26. 3 ( 0. 8)  a  20. 3 ( 4.8)  16.7 ( 3.3) l7.0 ( 7.1) 20.2 ( 2.4)  17.8 ( 4.7)  a b  18. 6 ( 3.5)  a  16. 6 ( 4.5)  b  a  -0.5 (6.1)  0.5 ( 0.4)  13.6 ( 3.7)  8.8 ( 1.6)  23. 2 ( 3.8)  9.1 ( 3.3)  19. 1 ( 4.7)  8.6 ( 6.0)  b  b  a  b  o . .5 .6) ( 3.  a b  a  l l . .1 ( 3. • 6)  5.9 ( 4.3)  7 .,5 ( 4. .0)  5.7 ( 4.3)  7..1 .3) ( 5.  a b  b  Table 3-9.  N  continued. Neutral-Detergent Fibre  C e l l Contents  F  C  F  Acid-Detergent Fibre  ( Percent of oven dry weight ) F+C F C F+C  C  F  C  F+C  Shrubs Vaocinium  alaskaense  Spring  2  2  Summer  3  3 .  a  Fall-Winter  6  6  a  Annual  11  11  45. 2 (18. 8)  a  41. 7 ( 6.0) 42. 5 ( 2.9) 42. 8 ( 7.0)  59. ,4 .0) ( 6.  3  58. 0 ( 2. .9)  a  44. ,9 ( 7.3)  b  51..1++ ( 9.1)  52. 3 (14. 0)  54..8 (18..8)  a  40. .6 .0) ( 6.  a  49. 8 ( 9.9)  a  43. 7 ( 5.5)  a  a  58. .3 .0) ( 6.  a  a  46. 9 ( 9.0)  Acid-Detergent Lignin  42. .0 •( 2.• 9) a  57. ,5 ( 2. .9)  b  57.,2+ ( 7. ,0)  48.,9 ( 9. ,1)  47. .7 (14,.0)  a  50. .2 .9) ( 9.  a  55. .1 .3) ( 7.  a  56. .3 .5) ( 5.  a  a b  53.,1 ( 9. .0)  51. .5 ( 2. .2)  a  b  37. .2 ( 0. • 6)  a  4 3 ..5 .2) ( 6.  a  43..2 .7) ( 6.  Cellulose  32. .0 (11..7)  3  33. .3 (11..5)  a  41. .7 ( 9. .3)  a  41. ,7 .2) (.1.3. 35, .2 ( 7, • 6)  42, .6 ( 7. .6)  37..6 (10..3)  40.,4 .9) ( 8.  Hemicellulose  ( Percent of oven dry weight ) F  C  F+C  F  C  F+C  F  C  F+C  25, .9 (12..3)  3 ..3 (21..0)  8 . .6 ( 5. • 7)  5 ..9 (12..9)  21. .1 .6) ( 6.  8, .7 (13.• 2)  Shrubs Vaocinium  alaskaense, 3  Summer  a  Fa 11-W i nter Annual  (continued)  16. 7 ( 6.7)  Spring  23. 7 ( 4.4) 20. 4 ( 5.6)  a  20. 8 ( 5.4)  a  a  a  l 5 . .0 ( 3. .8)  l 4 ., 9 .0) ( 2. l 9 ., 6 ( 8, .1) .16.. 3 ( 4. .5)  a  l 5 . .8 .6) ( 4.  n  i 9 ., 3 ( 5. .7) 20. .0 ( 5. .7)  U  .1.8.,5 ( 5. • 3)  34. ,8 ( 8. .9)  a  13. ,5 • 0) ( 5.  a  24. . 5 ( 5. .2)  a  22..1 (10..9)  l7. 1 ( 7.9)  a  18. 4 (13. 6)  a  22. 9 ( 5.9)  a  19. 3 ( 9.2)  a  l 5 . .9 ( 9. .5)  a  23. .7 ( 4, .6)  a  46..9 .0) ( 9.  a  a  a  l 4 .,0 ( 3. • 9)  14.,0 ( 9. .9)  a  3  13. .4 ( 4. .1)  3  11.,3 ( 7. .3)  3  a  l 4 ..9 (11.• 5) 13. .7 ( 3. .8)  3  12..6 ( 8. .6)  Table 3-9.  N -  continued. Neutral-Detergent Fibre  C e l l Contents C  F  F  Acid-Detergent Fibre  ( Percent of oven dry weight ) F+C F C F+C  C  F  C  F+C  Shrubs V.  parvifolium Spring  2  2  a  Summer  2  2  3  50. 7 (10. 7) 50. 4 6)  ( o.  Fall-Winter  5  6  A2. 0 ' ( 5.9)  Annual  9  10  45. 8 ( 7.2)  a  63. 6 (11. 7)  3  a b  54. 1 ( 4.5) b  4 9 . 1+ ( 5.4)  53. 0+ ( 8.3)  ab  a  57,.1 (11..8)  a  5 2 ..2 ( 3. .4)  a  45. ,9 ( 6. .5)  a  49, .4 (10,.7) 49, .7 .6)  36. 4 (11. 7)  a  ( o.  58. .0+ ( 5. • 9)  b  49.,6 ( 8. • 4)  Acid-Detergent Lignin  46. 0 ( 4.5)  a b  a b  50. 9 ( 5.4)  b  54.,2 ( 7. ,2)  a  42 .9 (11,• 8)  a  4 7 ,.8 .4) ( 3.  a  54. .1 ( 6. .5)  a  50..4 ( 8. .4)  42.,8 (10..0)  b  47. 0 ( 8.3)  35,.4 (13,.7)  a  5 1 ..0 (14..1)  a  42. .6+ ( 7. .4)  a  Cellulose  3 1 ,.1 ( 3, .1)  a  33,.2 ( 8, .5)  36. .5 (22..6)  a  37. .7 ( 7. ,8)  a  43,.7 (17.• 5)  40. ,1 ( 7. .7)  36..1 ( 9. .9)  39.,5 (10.,3)  Hemicellulose  ( Percent of oven d r y weight )  IT  C  F+C  F  C  F+C  F  C  1 4 , .0 ( 3. .0)  5 ,.3 (14,• 9)  9 ,.6 (10,.1)  l . .4 (14..8)  9 ,.5 (18,.1)  4 ..1 (14..9)  Shrubs V. parvifolium,  (continued)  Spring  a  Summer  a  Fall-Winter  3  Annual  17. .8 ( 4. .2)  a  18. ,9 ( 5. .7)  a  i l . .8 .8) ( 1.  a  1 9 . ,3 ,7) ( 3.  a  l6. 3 .9) ( 4.  a  18.,6 ( 3. .6)  l 2 ., 3 • 2)  15,.0 .0) ( 4,  a  ( o.  13. 4 •2). ( 3.  17. 6 ( 9.5)  a  15. .3 .4) ( 5,  a  l 7 . ,7 ( 4. • 0)  a  16.,0 ( 4. .3)  32. 1 ( 8.5) 28. 1 ( 4.8)  25. 9 ( 9.0)  18 .8 ( 2.9)  a  24 .7 (20 .8)  a  2 3 .5 • 8) ( 7.  a  a  a  3  22 .4 (10.• 4)  18. 2 ( 5.8)  ab  28. 4 (13. 6)  25. 8 ( 5.9) 24. 1 ( 9.5)  a  15. .1 ( 3. .8)  b  11.,2 ( 9. .3)  a  a  a  13. .2 ( 2. .8)  a  10..9 ( 8. • 7)  a  a  i 4 , .1 ( 3. .3)  11..0 .8) ( 8.  Table 3-9.  N  continued. Neutral-Detergent Fibre  C e l l Contents  F  C  F  Acid-Detergent Fibre  ( Percent of oven dry weight ) F+C F C F+C  C  F  C  F+C  Conifers Pseudotsuga  menziesii 57.6 ( 1.8)  Spring  2  2  a  Summer  2  2  3  Fall-Winter  6  6  a  10  10  Annual  59.4 (10.6) 55.4 ( 3.0) 56.6 ( 4.5)  a b  62. J ( 7. .3)  67. ,9 ( 7.1)  a  6 2 .,3 ( 3. .8)  a  a  60. .4++ ( 3. .9)  b  62..3++ .0) ( 5.  42.4 ( 1.8)  a  40.7 (10.6)  60. ,8 ( 6. .7)  a  57. .9 .2) ( 4.  a  a  59..5 .5) ( 5.  F  C  37. .7 . ( 3..8)  43.4++ ( 4.5)  37.2 ( 7.3)  a  39.2 ( 6.7)  a  42.1 ( 4.2)  a  a  3  a  44.6++ ( 3.0)  Acid-Detergent L i g n i n  32. ,1 ( 7. .1)  a  39. ,6 .9) ( 3.  a  a  40.6 ( 5.5)  37..7 .0) ( 5.  25. .1 .0) ( 5.  a  29. .5 .3) ( 1.  a  35. ,9 .3) ( 1.  a  34. .5++ .5) ( 1.  a  Cellulose  28,.2 .2) ( 3,  30. .4 .9) ( 6, 32, .0 .9) ( 2. 31,.6 .3) ( 4.  Hemicellulose  ( Percent of oven dry weight ) F C F+C  F+C  a  a  35.,1++ .5) ( 1.  31. .6 .9) ( 5.  27. ,2 .0) ( 5.  36. ,0 .5) ( 1.  F  C  F+C  4, .9 ( 2. .1)  5 ..7 .5) ( 1.  12. .7 .2) ( 1.  8 . ,7 •( 7..0) a  .3) ( 2,  io,.1  .0) ( 4,  .1 ( 3. .1)  8,.3 .2) ( 4,  9,.6 ( 4, .1)  8..9 ( 4, .1)  Conifers Pseudotsuga  menziesii,  Spring Summer Fall-Winter Annual  (continued)  ab  20.4 ( 0.9)  15.5 ( 1.4)  18..0 ( 2. .8)  13.0 ( 0.03)  a  a  a  a  a  a  16.5+ ( 0.7) ..  l 7 . .8 .0) ( 2.  16.1 ( 0.8)  19.5+ ( 0.8)  b  10.4 ( 4.8)  a  a  a  a  a  15.3 ( 1.8)  17. .6 .4) ( 3.  14.6 ( 0.2)  20.6 ( 0.5)  15.5+ ( 1.4)  13.0 ( 2.6)  11.3 ( 2.4)  a  a  a  a  14.7 ( 1.9)  18. ,5 .5) ( 3.  15.8 ( 2.7)  21.3 ( 0.4)  a  11.6 ( 2.6)  12.8 ( 4.1) 14.7 ( 2.0) 13.5 ( 2.9)  a  6 . ,5 .4)  ( o.  4 . .8 .3) ( 9. a  a  io..1  a  b  ab  a  a  io.  Table 3-9.  continued. Neutral-Detergent Fibre  C e l l Contents  Acid-Detergent Fibre  ( Percent of oven dry weight ) — - F+C F C F+C  C Conifers  Thuja  plicata  Spring  2  2  Summer  3  3  Fall-Winter Annual  6  6  11  11  53.. 3 ( 7, .9)  3  3 b  58..1 .4) ( b.  5 7 .\l ( 2. ,4)  a  60.,9 ( 3. •1)  a  b  58.,6 ( 4. •6)  55,.7 ( 6. • 5)  a  58..8 ( 3. .1) 6 1 .,7 ( 3.1)  60. 2+ ( 3.7)  46. 7 ( 7.9)  a  ab  5 8 ..2 ( 2. • 6) 61.,3 ( 3. ,0)  b  59..4 ( 4.2)  a  a b  42. 4 ( 2.4)  44 .3 ( 6. • 5)  41..2 ( 3. .1)  39. 1 ( 3.1)  41. 4+ ( 4.6)  3 8 .4 ( 3. • 4)  a  a  b  Acid-Detergent L i g n i n  4 ! .9 ( 6. .4)  a  4 1 ,.8 ( 2. .6)  3b  38..3 ( 3. • l)  38..7 .0) ( 3.  a  3  b  39.,8 ( 3. .7)  40..6 ( 4. • 2)  33..2 ( 0. .3)  b  a b  32,.9 ( 0. .9)  b  3 5 ..4+ ( 2. .8)  b  35.,3 ( 2.9)  35.,1 ( 7.6)  Cellulose  32'..7 • 7) ( 1.  41,.9 (10..9)  a  b  33,.0  ( o. .6) 34..1 ,6) ( 2.  b  35..2 ( 5.6)  Hemicellulose  ( Percent of oven dry weight ) F C F+C  F+C  4 5 .5 (17.• 1)  a  F  C  Conifers  Thuja plicata, Spring Summer Fall-Winter Annual  (continued) 22.2+ ( 1.1)  a  23.8+ ( 3.2)  a  21.5 ( 3.9)  a  22. 7 ( 2.7)  16. 8 ( 1.0)  a  22.8 ( 3.3)  h  l7.5 ( 0.1)  a  19. 6 ( 3.6)  19., 5 .2) ( 3.  3  23. 3 ( 3.0)  a  a  i9. 5 ( 3.2)  21..1 ( 3.5)  16.2 ( 2.3)  a  9.4 ( 2.9) a  15.1 ( 1.5)  a  12.9 ( 3.9)  28,.7 (18..0)  22,.4 (12,.7)  a  a  V  i o ..2 ( 2. .4)  a  16..3 ( 2. .8)  a  17.,2 (11. 3)  a b  8 ,.4 ( 4. .5)  3 b  -3 .6 (23 • 5)  2 .,4 (15..5)  a  a  .7 ( 2. .4)  9 ..2 .2) ( 2.  8,.3 ( 2, .6)  8 ..7 ( 2.2)  1 5 ..7 ( 2. .0)  3 . ,7 ( 2. ,3)  5 ..6 ( 2. .1)  4. 6 ( 2.3)  15..1 ( 8. • 4)  6..0 ( 3.6)  4,.7 ( 8. .8)  a  b  a  a  3  a  -  5. 3 ( 6.6)  Table 3-9.  N  continued. Neutral-Detergent Fibre  C e l l Contents  F  C  F  Acid-Detergent Fibre  ( Percent of oven dry weight ) F+C F C F+C  C  F  C  F+C  Conifers Tsuga  heterophylla  Spring  2  2  Summer  2  2  a  Fall-Winter  6  6  a  10  10  Annual  a  65. 4 ( o. 5)  66. 0 ( 7.7) 59. 6 ( 5.5) 62. 0 ( 5.8)  71. 0 ( 8.3)  b  a b  64. 6 ( 5.4) 6 1 . 0+ ( 5.4)  a  63. 7 ( 6.7)  68. 2 ( 5.8)  a  65. 3 ( 5.5)  a  60. 3 ( 5.3)  a  a  a b  b  34,.6 ( 0, .5) 34,.0 .7) ( 7.  62. 8 ( 6.1)  Acid-Detergent L i g n i n  F  C  29.0 ( 8.3)  b  ab  40, .4+ .5) ( 5,  35.4 ( 5.4)  ab  39.0 ( 5.4)  a  38..0 .8) ( 5.  a  31, .8 .8) ( 5.  a  3 4 ..7 ( 5. • 5)  a  39. ,7 .3) ( 5.  a  b  36.3 ( 6.7)  37..2 ( 6. .1)  32. .2 ( o..7) 35. .0 (12.• 7) 32. .8 ( 3. .0)  33..1 ( 4. .9)  Cellulose  a  37. .5+ (12..3)  a  34..8 (11..6)  a  a  a  32..9 (11..3)  27. .6 ( 6. • 9)  36. ,2 (10..3) 33. .8 .2) ( 8.  33..0 ( 8. .5)  Hemicellulose  ( Percent of oven dry weight ) F C F+C  F+C  22. .9 ( 7. .5)  3  F  C  F+C  6, .1 o,.9)  4. .2 ( 2. .2)  Conifers Tsuga heterophylla, Spring  (continued) l 9 ., 3 • 2) ( 3.  a  22. ,7 .5) ( 1.  a  i 9 .,5 ( o..3)  a  a  Summer  a  Fall-Winter  a  Annual  20..5 ( 2. .3)  l3.7 ( 5.8)  a  i8.3 ( 4.3)  a  11.7 ( 8.7)  a  14. 6 ( 5.9)  16.5 ( 5.0)  a  20.5 ( 3.7)  3  15.6 ( 6.8)  a  17.5 ( 5.3)  l 2 .,9 ( 2. .5) 12. .3 (11..2) 15. .1 ( o..8)  13..4 ( 5. .3)  9.2 ( 1.7) a  i9.2 ( 8.0)  a  33.5 (26.9)  a  20.6 (16.7)  a  l l . .1 ( 2, • 8)  a b  !5..7 .9) ( 8.  a  2 , .4 ( o,.2)  - o , .9 ( 4, .9)  a  (  24,.3 (18..8)  7 . .6 .8) ( 3.  -2, .1 .9) ( 6, a, .3 ( 6. • 7)  17,.0 (12,.4)  4..9 .0) ( 5.  3..4 .3) ( 6.  a  a  b  a  a  a  b  - l . ,5 ( 4. .9) 5 . .9 .5) ( 5. b  4.,1 ( 5.6)  Table 3-9.  N  continued. Neutral-Detergent Fibre  C e l l Contents  F  C  F  C  Acid-Detergent Fibre  ( Percent of oven dry weight ) F+C F C F+C  1  F  C  F+C  Lichens Alectoria  sarmentosa  Spring  2  83.0 ( 1.7)  a  77.2 ( 8.3)  a  75.7 ( 6.3)  a  Summer  3  a  Fall-Winter  6  a  11  Annual  17.0 ( 1.7)  a  22.8 ( 8.3)  77.5 ( 6.5)  C  (  4.0 - )  15.5 (10.6)  a  24.3 ( 6.3)  5.9 ( 5.6)  22.6 ( 6.5)  8.2 ( 7.8)  Acid-Detergent L i g n i n  F  a  a  Cellulose  •. F+C  Hemicellulose  ( Percent of oven dry weight ) F C F+C  F  • Lichens Alectoria  sarmentosa,  (continued) i.o ( 1.4)  Spring  3.0 ( 1.4)  Summer  3.3 ( 0.2)  Fall-Winter  1.6 ( 0.2)  2.7 ( 0.3) '  Annual  2.7 ( 1.0)  6.3 ( 8.4)  a  a  3  a  12.2 (10.8)  a  a  13.0 ( 1.7)  a  7.3 (18.8) a  18.4 ( 8.1)  a  14.4 (11.4)  C  F+C  Table 3-9.  continued. Neutral-Detergent Fibre  C e l l Contents  — ( Percent of oven dry weight ) F+C F C F+C  Acid-Detergent Fibre  F  . C  F+C  Forbs Epilobium  angustifolium  Spring  2  a  87.2 ( 6.A)  a  Summer  2  a  73.8 ( 8.4)  a  Fall-Winter  1  a  Annual  5  55.8  Acid-Detergent  F  C  a  26.2 ( 8.4)  a  a  75.6 (1A.0)  11.2 ( 4.4)  12.8 ( 6.4)  14.9 ( 4.1)  44.2  a  14.7 ( 5.1)  24.5 (14.0)  Lignin  Cellulose  F+C  ( Percent of oven dry weight ) F C F+C  21.3  Hemicellulose  F  C  Forbs Epilobium  angustifolium,  (continued)  Spring  6.1 ( 2.9)  Summer  3.4 ( 1.6)  Fall-Winter Annual  5.1 ( 1.5)  a  a  a  a  4.9  4.8 ( 2.1)  ab  '  b  11.5 ( 2.5)  16.5 9.9 ( 5.1)  l.7 ( 2.1) a  11.3 (12.6)  a  a  22.9  9.8 (10.9)  F+C  Table 3-9.  N F  continued. Neutral-Detergent Fibre  C e l l Contents C  F  Acid-Detergent Fibre  ( Percent of oven dry weight )  C  F  F+C  C  F  F+C  C  F+C  Ferns Blechnum  spicant  Spring  2  2  a  Summer  2  2  a  Fall-Winter  5  5  a  Annual  9  9  48.8 ( 9.2)  a  37.3 ( 1.0)  a  45.7 ( 5.9)  a  44.5 ( 6.8)  50. 7 (11. 8)  a  55. 1 ( 7.2)  a  5 6 . 4+ ( 3.2)  a  54. 8++ ( 5.9)  49. 7 ( 8.7)  a  46. 2 (11. 1)  a  51. 0 ( 7.2)  a  49. 7 ( 8.2)  51.3 ( 9.2)  a  62.8 ( 1.0)  a  54.3++ ( 5.9)  a  55.5++ ( 6.8)  Acid-Detergent L i g n i n F  C  49.3 (11.8)  a  44.9 ( 7.2)  a  43.7 ( 3.2)  a  45.2 ( 5.9)  50, .3 .7) ( 8,  3  53,.8 • (11,.1)  b  49. .0 .2) ( 7.  a  50..3 ( 8, .2)  50. .4 ( 1. • 1)  a  74. .7 ( o..4)  a  45. ,0+ ( 3. ,6)  a  52..0++ (12. 5)  Cellulose F  a  47. .8 (11..5)  a  34. .3 ( 4.5)  a  39.,8 ,3) ( 9.  48, .1 .2) ( 7,  6 1 ..2 (16..9)  40. ,1 .8) ( 6.  46.,1 ( 9. .4)  Hemicellulose  ( Percent of oven dry weight )  F+C  45. .8 (11..6)  C  F  C  o..9  3.5 ( 0.2)  F+C  F+C  Ferns Blechnum spicant, Spring  (continued) 20.0 (12.7)  a  28.0 ( 3.6)  a  10. 9 ( 0.2)  a  a  Summer  a  Fall-Winter  3  Annual  19.6 ( 9.6)  l9.4 ( 4.1)  a  12.7 ( 8.6)  a  l.3.0 ( 9.0)  a  15.0 ( 6.8)  19.7 ( 7.7)  a  20.3 (10.4)  a  11.9 ( 5.3)  a  17.3 ( 8.3)  30. .5 (13..8)  a  46. .7 ( 4..0)  a  35. .8 ( 4..5)  a  37..7++ (10..0)  26.4 (15.7)  a  35.1 ( 2.9)  a  25.7 ( 6.9)  n  29.1 ( 9.1)  b  28. 4 (12. 3)  40. 9 ( 7.3)  b  ( 8. .1) a  - l l . ,9 .3) ( 1.  bc  -2.9 ( 4.2)  a  2 ..2  ( 4..9)  - 7 ..4 .8) ( 5.  a  30. 7 ( 7.5)  9 .,2 ( 4..7)  9.4 ( 3.6)  9 ..3 ( 3.9)  31. 8 ( 9.0)  2..7 (10..0)  5.3 ( 6.0)  4..2 ( 7.5)  b  a  a  T a b l e 3-9.  N  continued. Neutral-Detergent Fibre  C e l l Contents  F  C  F  Acid-Detergent Fibre  ( P e r c e n t o f oven d r y w e i g h t ) F+C F C F+C  C  F  C  F+C  Ferns Polystichum  munition  Spring  2  2  a  Summer  2  2  a  Fall-Winter  5  5  a  Annual  9  9  40.8 (24.0)  a  29.4 ( 0.4)  b  30.5 ( 3.9) 32.5 (10.1)  a b  49. 5 (10. 1)  a  3 3 . 9+ ( 1.2)  b  3 8 . 2+ ( 5.6)  a b  39. 7++ ( 7.9) -  45.1 (15.8)  a  31.6 ( 2.7)  3  34.3 ( 6.1)  a  36.1 ( 9.5)  59.3 (24.0)  a  70.7+ ( 0.4)  b  69.5++ ( 3.9) 67.5++ (10.1)  Acid-Detergent L i g n i n F  C  3 b  5 0 . ,5 (10. 1)  a  66. 1 ( 1.2)  b  61. 8 ( 5.6)  a b  60. 3 ( 7.9)  5 4 , .9 (15..8)  a  6 8 . ,4 ( 2. .7)  a  6 5 .,7 ( 6. .1)  a  63..9 ( 9.5)  5 4 .2 ( 2.9)  a  5 4 .5 ( 3.0)  a  5 1 .3 .8) <  3  52 .6 ( 4.1)  Cellulose  a  5 3 , .8 ( 4, .3)  5 6 .5 (10 .5)  a  5 0 .9 ( 7.0)  a  5 5 . .5 ( 6. .4)  5 1 . .1 .6) ( 5.  52,.7 .0) ( 7,  52.,7 ( 5.6)  Hemicellulose  ( P e r c e n t o f oven d r y weight ) F C F+C  F+C  5 3 .5 ( 6.8)  F  • F+C  C  Ferns Polystichum  munition,  Spring Summer Fall-Winter Annual  (continued)  30.0 ( 0.5)  a  b  23.5  24.0 ( 2.0)  a  a  26.8  (1.1)  (5.5)  24.2 (0.3)  26.0 .(1.4)  b  25.9 ( 3.2)  a  25.6 ( 3.0)  27.0 (3.6)  a  a  25.1  ( 3.8) 25.1 ( 1.3).  a  25.7 ( 3.0)  24.3 ( 2.4)  a  31.0 ( 1.9)  a  29.5 ( 3.9)  a  28.2 ( 3.9)  29.5 ( 4 ..8)  a  8  29.7  ( 5.0) 30.4 ( 7,3)  a  29.8 (4.5)  26.9 ( 4.3)  a  a  16.2 ( 2.6)  9.6 (11.6)  a  10.9 • ( 8.9)  a  30.3 ( 3.2)  a  29.9 ( 4.8)  a  29.0 ( 4.2)  14.8 (11.2)  fl  3  a  5.1 (26.9) a  18.2 ( 2.6)  -3.0 (3.3) a  3  7.5  I.  9  i.o  (16.3)  -V 7  V a l u e s i n a column w i t h a common s u p e r s c r i p t l e t t e r ( a , b, c ) a r e n o t d i f f e r e n t a t p < 0.05 l e v e l as d e t e r m i n e d by a n a l y s i s o f v a r i a n c e and S c h e f f e ' s t e s t . S i g n i f i c a n t d i f f e r e n c e between f o r a g e c h a r a c t e r i s t i c s i n f o r e s t e d and c u t o v e r a r e a s i n d i c a t e d a s : + (p < 0.05) and ++ (p < 0.01). A n a l y s i s by t - t e s t . S i g n i f i c a n c e i n d i c a t o r i s b e s i d e t h e measure h a v i n g t h e g r e a t e r v a l u e .  12.9 ( 7.9) 14.6  ( 7.3) 11.6 ^ (10.4) jo  134  has been shown by others (Short et a l . 1975).  Krueger (1967) documented  rapid and s i g n i f i c a n t changes i n carbohydrate (NDF) l e v e l s i n Pseudotsuga menziesii during the growing season.  In most seasons, c e l l content and  NDF were not d i f f e r e n t i n a species c o l l e c t e d i n timber compared to cutover areas. Where d i f f e r e n c e s d i d occur, higher l e v e l s of c e l l content and lower l e v e l s of NDF were observed i n p l a n t s from cutover areas.  S t a t i s t i c a l comparisons  of mean annual NDF content of a l l species regard-  less of type are presented i n Table 3-10.  Patterns were s i m i l a r to those  observed f o r dry matter, crude p r o t e i n and DDM. ture  (e.g., c o n i f e r s ) or c l o s e l y related  plants (e.g. Vaccinium spp.),  did not d i f f e r s i g n i f i c a n t l y i n NDF content. NDF  content  ranged  from  63.9  Plants of s i m i l a r struc-  Among the species examined,  (±2.2%) i n Polystichum muniturn  (±1.9%) i n A l e c t o r i a sarmentosa.  to  22.6  NDF d i d not show any trend of increased  l e v e l s i n woody species such as shrubs and c o n i f e r s , as might be expected. Rather, ferns, which generally are considered herbaceous, contained high l e v e l s of NDF  due  to t h e i r high l i g n i n and c e l l u l o s e content which i s  discussed l a t e r i n conjunction with those components.  To summarize, A l e c t o r i a sarmentosa was  lowest i n NDF and highest i n c e l l  contents of a l l species studied. This was r e f l e c t e d e a r l i e r i n i t s higher DDM.  Lichens  contain f i b r e  i n the  form  of  lichenin  and  isolichenin  (Scotter 1972) which may not react i n the same way to the Van Soest detergent solutions  as do the more common carbohydrates  (e.g., c e l l u l o s e ) .  D i f f i c u l t i e s i n f i l t r a t i o n of detergent-treated l i c h e n samples suggested t h i s was  the case.  C o u r t r i g h t (1959) i n Scotter (1972) noted t y p i c a l l y  low l i g n i n contents i n l i c h e n s , which would reduce  total fibre  (NDF).  135  Low lignin levels were also observed i n lichens analyzed in the present study (Table 3-7).  Ferns contained highest NDF and lowest cell contents  and also were low in DDM as discussed earlier.  Woody plants (conifers and shrubs) contained similar levels of NDF while active growth was occurring but differed from each other later in the growing season and i n the dormant period.  Most forage types differed  significantly from each other in NDF and cell content levels in summer and winter, apparently reflecting their varied degrees of maturation and lignification.  Seasonal differences did not occur i n individual forage types, although NDF levels increased from spring to fall-winter, and were significantly different between these two periods in most species, reflecting the stage of maturity of the tissue.  Species and types collected in cutovers were consistently lower in NDF and higher in cell contents than the same plants from forested areas, probably reflecting the increased sunlight and better growing conditions in the open areas.  Differences  between Gaultheria shallon  and the other shrub species,  vaccinium alaskaense and V. parvifolium, may be in part due to the evergreen habit of G. shallon, which would be expected to contain less NDF as a result of leaves being included in the samples a l l year around. Greater proportions of large twigs may help explain the higher NDF level of Pseudotsuga menziesii compared to Tsuga heterophylla.  136  Acid-Detergent Fibre (ADF), Acid-Detergent Lignin (API) and Cellulose  These measures are discussed together as they have similar effects on the degree to which forage plants can be utilized by deer. ADF and i t s components,  cellulose  (lignin) being  and  ADL,  essentially  are  relatively  indigestible  low  in digestibility,  (Van Soest 1963).  Reagor (1970) reported that cell wall content  (NDF)  ADL  Short and  of mature woody  tissues is less digestible than that of herbages, apparently due to the inhibitory effects of lignin on digestibility.  Based on this finding,  and the fact that small ruminants such as deer have a high rumen turnover rate, they concluded that the entire NDF fraction of mature woody twigs is metabolically unavailable to deer.  These measures were examined in  the current study which included herbaceous as well as woody species, to assess differences and examine their relation to digestibility and energy values.  In comparisons  of forage types on an annual basis, ferns contained sig-  nificantly higher levels of ADF, ADL and cellulose than a l l other types (Figure 3-5, Table 3-7).  Forbs and lichens were consistently low and not  different from each other in these measures.  The woody types, conifers  and  shrubs were significantly  shrubs  contained similar levels of ADL;  higher in ADF and cellulose than conifers.  The high level of ADL in ferns  is striking, particularly since during part of the year they were compared to shrub samples made up only of woody twigs without leaves.  Seasonal levels of ADF, ADL and cellulose in the different forage types are presented in Table 3-7.  Ferns were significantly higher in ADF than  137  other types at a l l seasons.  Next highest levels of ADF occurred in coni-  fers and shrubs, which had similar patterns and levels of ADF in most seasons, as did lichens and forbs which were lowest in ADF.  ADL values in types followed a pattern similar to ADF, except that fewer differences occurred between types.  Ferns were not different from coni-  fers and shrubs except in the spring when ADL was higher in ferns.  Cellulose levels ranged from a high of 35.6% to a low of 1.0%  (+2.7%) in ferns in summer  (±1.0%) in lichens in spring.  Cellulose values are  derived by subtracting ADL from ADF values, so patterns of variation in cellulose content generally reflect those observed for ADF and ADL.  Shrubs from forested areas were higher in ADF and ADL than in cutovers in fall-winter and on an annual basis (Table 3-8).  ADL levels in conifers  were higher in forested areas than in cutovers during a l l seasons.  Again,  this probably is a reflection of the increased cell content and overall reduced  fibre levels associated with better conditions for growth, par-  ticularly increased sunlight, in cutover areas.  Within types, species were compared for annual differences in ADF levels. The three conifer species or the three shrub species did not differ from each other in forest or in cutovers but among ferns, Polystichum munitum was  significantly higher in ADF  more woody structure.  than Blechnum spicant, reflecting i t s  138  Seasonal and annual levels of ADF, ADL and cellulose for each species are shown in Table 3-9. A fairly consistent pattern of no significant variation between seasons was evident for most species. The few statistical departures are indicated i n Table 3-9.  These departures generally in-  volved higher levels of ADL or ADF in spring and are in contrast to the findings of Short et a l . (1975) who noted lowest ADF and ADL levels in twigs in spring and nonsignificant differences in the other seasons, since twigs are apparently mature by summer.  These departures may also reflect  the observation, discussed earlier, that changes in levels of fibre components may precede major phenological changes, such as bud burst, upon which season delineations were based.  In leaves, Short et a l . (1975)  reported few seasonal differences in ADL and ADF between seasons, and highest  levels  (nonsignificant) occurred in summer.  The woody plant  samples analyzed in this study were mixed leaves and twigs and this may be an additional reason a definite seasonal pattern of variation i s not evident.  Within species, significant differences in ADF, ADL and cellulose between forested and cutover areas on an annual basis were few although plants from cutovers contained consistently lower levels of these components. Significantly lower ADF levels in cutovers occurred in Gaultheria shallon, Pseudotsuga menziesii and Blechnum spicant (Table 3-9).  Comparisons made between individual species analyzed for ADF, ADL and cellulose, based on annual average levels of these components, are contained in Table 3-10.  Polystichum munitum contained highest levels of  ADF and ADL, 52.7 (±1.3%) and 25.7 (±0.9%), respectively.  Corresponding  139  Table  3-10.  S t a t i s t i c a l  comparisons  are^averages  o f  f o r plants  annual  c o l l e c t e d  f i b r e  contents  i n forested  o f  forage  a n dc u t o v e r  species. areas  Values  combined.  NEUTRAL-DETERGENT FIBRE  V/////////////////////, VAAL  POMU  VAPA  GASH  BLSP  PSME  THPL  '  TSHE  EPAN  ALSA  //////////////////////, 50.4  53.1  63.9  ACID-DETERGENT  50.3  44.9  40.6  40.6  37.1  24.5  22.6  GASH  THPL  TSHE  PSME  EPAN  ALSA  14.7  8.2  FIBRE  '//////////////////////, POMU  BLSP  VAAL  VAPA  •••••••••••••••••••••••••••••••••••••• 52.7  46.2  V/////////////////////  40.4  39.5  '/////////////,  \ \ \ \  VAAL  GASH  PSME  TSHE  3LSP  VAPA  EPAN  18.5  18.4  18.0  17.5  17.3  16.0  . 4.8  VAPA  VAAL  GASH  37.8  35.2  33.0  31.6  ACID-DETERGENT LIGNIN  THPL  POMU  ALSA  '///, 25.7  21.1  2.7  CELLULOSE  ^  ^  ^  BLSP ^  ^  //////////////////////.  POMU  ^  ^  33.3  TSHE  THPL  EPAN  PSME  ALSA  '//////////////////////  ^  24.1  29.0  21.0  19.1  17.0  VAPA  EPAN  15.1  13.5  GASH  THPL  9.9  6.3  HEMICELLULOSE  V//.  \ \ \ \ ^ ALSA  VAAL  14.4  12.6  'Forage  species  11.2  codes  SHRUBS  v.-.-.-  GASH  CONIFERS  / / / / .  PSME  LICHEN FORBS  ALSA EPAN  FERNS  s\\v  ^Values  a r epercent  Species by  POMU  BLSP  and  9.8  11.0  designations  8.9  a r eas  Gaultheria shallon Pseudotsuga menziesii - Alectoria sarmentosa •» Epilobium angustifolium = Blechnum spicant '  '/////////////  7.1  VAAL  »  THPL  =  Vaocinium. alaskense Thuja plicata  POMU  =  Polystichum munitum  VAPA  «  TSHE  =  and  l i n e  a r e s t a t i s t i c a l l y  S c h e f f e ' s  t e s t .  4.0  '/. parvifolium Tsuga hetercphyl  d r y weight.  b y common  o f variance  4.1  BLSP  follows:  =  o f oven  TSHE  5.3  =  n o tunderlined a n a l y s i s  type  PSME  d i f f e r e n t  (p £  0.05)  a s  determined  140  values for Alectoria sarmentosa, which was lowest in ADF and ADL were 8.2 (±2.3%) and  2.7  (±0.4%), respectively.  As  observed  for other forage  characteristics, species within types showed similar levels of ADF,  ADL  and cellulose.  In summary, a wide range in levels of the relatively indigestible components of cell walls (ADF, ADL and cellulose) was observed.  Ferns were  consistently higher in these components than the other forage types and were also low in digestibility.  Lichens were low in ADF  and this is  probably the result of their having structural carbohydrates quite different from the lignocellulose common to most other plant types. Forbs were low in ADF, ADL and cellulose due to their herbaceous nature and correspondingly  small proportion of fibrous structural components. Definite  seasonal trends of increasing levels of ADF and ADL as might be expected with maturation of tissue were not apparent.  This observation probably  relates to the findings of Short et a l . (1975) indicating clear trends in phenological variation in twigs but not in leaves of woody browse plants. As previously discussed, the manner in which seasons were defined also have influenced the patterns observed.  may  Dietz (1972) also observed  differences in ADF, ADL and cellulose content between stems and leaves of shrubs, but generally levels  increased with maturation  in both plant  fractions.  Growth beneath a forest canopy as opposed to open cutover areas seemed to increase fibre levels, perhaps as a result of decreased sunlight and correspondingly decreased levels of digestible cell contents.  141  The three species of each of the woody forage types, conifers and shrubs, had similar ADF, ADL and cellulose levels, reflecting their similarities in structure.  Hemicellulose  Whereas the components of ADF in mature forages are largely indigestible, hemicellulose can be digested at least to some degree by rumen microbes and comprises a large portion of the digestible carbohydrates in the diet of ruminants (Van Soest and Wine 1967). Hemicellulose is not a characteristic single molecule but rather is a class of carbohydrates  comprised  of a number of different compounds, including xylans, arabans, galactans and mannans (Dietz 1972).  Hemicellulose values as presented here  (Table 3-7  and 3-8) may not be  entirely accurate due to some problems with the chemical analysis. the analysis, conducted  In  according to the procedures of Waldren (1971),  separate plant samples were digested in acid-detergent and in neutraldetergent solutions.  Robbins et a l . (1975) have since reported that a  sequential digestion as proposed by Bailey and Ulyatt (1970) would provide more accurate estimates of ADF and hemicellulose. Apparently a l l of the pectins and hemicellulose are not removed in the acid-detergent procedure when an intact plant sample is analyzed; whereas when the same sample is analyzed f i r s t for NDF and subsequently for ADF, these carbohydrates are solubilized and the ADF values more accurately indicate the lignocellulose fraction free of pectins and  hemicellulose.  Hemicellulose apparently  remained in some of the ADF residues of plants examined in this study, as  142  ADF exceeded NDF (of which i t should be only a component) in several instances. estimate  The effect of this incomplete  of ADF and a corresponding  separation would be an over-  underestimate  of hemicellulose.  Short et a l . (1975) had the same discrepancy i n some of the plant species they examined but did not speculate why.  Hemicellulose values presented here should therefore be considered only in the relative sense, i.e. as they differ broadly between forage types or species, and should not be treated as absolute values. As hemicellulose levels are normally low, small differences in measurement have a proportionally large influence on variability, thus hemicellulose is not discussed in the same detail as other variables.  Some ADF values pre-  sented earlier may be overestimated but the degree of error is less.  Statistical analysis indicated Alectoria sarmentosa to be significantly higher in hemicellulose on an annual basis than other forage types (Table 3-7).  Although lichens contain high levels of carbohydrates, hemicellu-  lose, rather than cellulose is present (Hale 1961), along with a s i g n i f i cant amount of lichenen and isolichenin which are readily digestible, at least by reindeer (Scotter 1972).  The other forage types were not dif-  ferent from each other in amounts of hemicellulose. On a seasonal basis, differences in hemicellulose between forage types were indicated only in the fall-winter period, when ferns and conifers were lower in hemicellulose than lichens and forbs (Table 3-7).  Within forage types, significant seasonal differences in hemicellulose occurred only i n shrubs and in ferns where spring values were less than in fall-winter (Table 3-8).  143  The only instance in which hemicellulose varied significantly relative to area of collection was in shrubs in fall-winter when values from forested areas were higher than in cutovers.  Seasonal levels of hemicellulose for individual species are presented in Table 3-9. Because negative values for hemicellulose occurred in several seasons, the validity of significant differences is questionable.  Among the 10 species analyzed, hemicellulose values ranged from 14.4 (±3.4) in Alectoria sarmentosa down to 4.0 (±1.9) percent in Blechnum spicant (Table 3-10). Generally, species within the same forage type did not differ from each other in hemicellulose content.  In summary, hemicellulose measurements reported are questionable, since the analytical technique employed did not allow a clear separation of this fibre component from ADF.  Solubility of Forage Plants  A measure of the amount of readily-available cell contents of a forage species can be estimated by determining saliva  (Uresk et al. 1975).  i t s solubility i n a r t i f i c i a l  In this study seasonal patterns of solu-  b i l i t y of selected species collected in cutover and forested areas were examined (Figure 3-9).  Seasonal trends are evident, and can be compared  to average DDM values, also indicated on the graphs.  Except for Alectoria  sarmentosa for which a seasonal trend was lacking, trends in solubility and DDM were similar with seasonal maximum and minimum values coinciding.  144  Alectoria  Vaccinium  sarmentosa  p < Solubility  (%)  Digestibility  40  (%) n70  30  Solubility 40  (%)  parvifolium 0.116 Digestibility' 70  r  30  60  20  h  20  50  10  |-  10  40  0  0 Jan  Oct  Apr  Jul  Oct  Jan  Apr  Jul  F i g u r e 3-9. S o l u b i l i t y and d i g e s t i b i l i t y of p l a n t dry matter incubated i n s o l u t i o n of a r t i f i c i a l s a l i v a f o r 48 hours. P o i n t s are means of d u p l i c a t e samples. A n a l y s i s by p a i r e d T t e s t . -O  =  •  = =  ---A.  average d i g e s t i b i l i t y f o r e s t e d and cutover s o l u b i l i t y of t i s s u e s s o l u b i l i t y of t i s s u e s  of t i s s u e c o l l e c t e d i n areas, c o l l e c t e d i n cutover a r e a s , c o l l e c t e d i n f o r e s t e d areas.  145  S t a t i s t i c a l comparisons from  forested  and cutover areas  Blechnum spicant parvifolium  (paired t - t e s t s ) of s o l u b i l i t y l e v e l s i n plants showed that differences occurred, i n  (p < 0.04), Thuja p l i c a t a  (p < 0.06) and Vaccinium  (p < 0.12), w i t h the highest l e v e l s of s o l u b i l i t y from the  cutover c o l l e c t i o n i n a l l instances.  D i g e s t i b i l i t y (DDM) of Forage Mixtures  Digestibilities 3-11.  of the forage mixtures evaluated are presented i n Table  Sixteen d i f f e r e n t d i e t s were evaluated and i n 12 of these, DDM was  greater than expected on the basis of the p r o p o r t i o n a l combination of DDM for  individual  component species.  D i g e s t i b i l i t y increases ranged  5.9  to 29.7 percent above expected l e v e l s .  from  The greatest increases i n  d i g e s t i b i l i t y of d i e t s over expected l e v e l s occurred during May, when DDM of i n d i v i d u a l species was r e l a t i v e l y high.  In 4 of the 16 d i e t s , DDM was  less than the c a l c u l a t e d p r o p o r t i o n a l DDM of the i n d i v i d u a l species (mean decrease = 7.7%).  The reasons f o r t h i s decrease are not apparent; how-  ever, three of these cases occurred i n t r i a l s run i n August, w i t h d i e t s that consisted of species which are p r i m a r i l y winter foods (Gaultheria s h a l l o n , A l e c t o r i a sarmentosa, Thuja p l i c a t a and Vaccinium alaskaense, the l a t t e r r e c e i v i n g more use on a year-round basis than the former three species). The reduced DDM of these d i e t s over that expected may have r e sulted  from  the rumen m i c r o b i a l population being adapted to a rather  d i f f e r e n t summer d i e t and not having the capacity a t t h i s time of year to digest a d i e t commonly used i n winter. The remaining case of reduced DDM of a d i e t  occurred i n February, i n a d i e t composed of three c o n i f e r  species and A l e c t o r i a sarmentosa.  The reasons f o r t h i s decrease are not  Table 3-11 . Dry matter d i g e s t i b i l i t y o f forage mixtures r e l a t i v e to expected based on v a l u e s f o r I n d i v i d u a l s p e c i e s .  Diet S l a s h Diet Forb-Shrub  Month July  Species  Epilobium Rubus Vaccinium  Composition  angustifolium spectabilis parvifolium  ProporObserved tion spp of Diet DDM  Expected spp DDM <%)  1  DDM  Expected Diet DDM (%)  Observe Diet DDM (%)  e  n  0.33 0.33 0.33  72.0 46.0 50.0  24.0 15.3 16.7  56.0  59.5  Difference (DDM -DDM )/ o e DDM e  (%)  Slash D i e t Forb-Shrub  July  Epilobium angustifolium Rubus spectabilis Vacainium parvifolium  0.50 0.25 0.25  72.0 46.0 50.0  36.0 11.5 12.5  60.0  65.3  Slash D i e t Shrub-Conifer  August  Gaultheria shallon Vaaainium alaskaense Thuja p l i c a t a  0.33 0.33 0.33  24.0 50.0 57.0  8.0 16.5 18.8  43.3  36.7  Timber D i e t Shrub-Conifer  August  Gaultheria shallon Vaccinium alaskaense Thuja p l i c a t a  0.33 0.33 0.33  22.0 36.0 51.0  7.3 12.0 17.0  36.3  38.8  Slash D i e t August Shrub-ConiferLichen  Gaultheria shallon Thuja p l i c a t a Alectoria sarmentosa  0.33 0.33 0.33  24.0 50.0 74.0  8.0 16.5 24.4  48.9  47.4  3.1  August Timber D i e t Shrub-ConiferLichen  Gaultheria shallon Thuja p l i c a t a Alectoria sarmentosa  0.33 0.33 0.33  22.0 36.0 74.0  7.3 12.0 24.4  43.7  39.3  -10.1  February Timber D i e t Conifer-Lichen  Thuja p l i c a t a Tsuga heterophylla Pseudotsuga menziesii Alectoria sarmentosa  0.25 0.25 0.25 0.25  50.0 46.0 52.0 81.0  12.5 11.5 13.0 20.3  57.3  56.0  - 2.3  -15.2  Table' 3-11.  Diet  Month  February Timber D i e t Conifer-ShrubFern-Lichen  Species Composition  continued.  ProporObserved tion of spp Diet DDM  Expected spp DDM (%)  Thuja plicata Gaultheria shallon Blechnum spicant Alectoria sarmentosa  0.25 0.25 0.25 0.25  50.0 32.5 40.0 81.0  12.5 8.1 10.0 20.3  Slash D i e t Shrub-Fern  February  Vaccinium Vaccinium Gaultheria Blechnum  alaskaense parvifolium shallon spicant  0.25 0.25 0.25 0.25  36.0 33.0 40.5 59.5  9.0 8.3 10.1 14.9  Slash Diet Shrub-Fern  Mar ch  Vaccinium Vaccinium Gaultheria Blechnum  alaskaense parvifolium shallon spicant  0.20 0.20 0.40 0.20  33.0 46.5 36.5 42.5  6.6 9.3 14.6 8.5  Slash Diet Shrub-FernConifer  April  Gaultheria shallon Blechium spicant Thuja plicata  0.33 0.33 0.33  26.0 32.5 52.5  8.6 10.7 17.3  Timber D i e t Shrub—Lichen  April  Vaccinium Vaccinium GaultJieria Alectoria  alaskaense parvifolium sJiallon sarmentosa  0.25 0.25 0.25 0.25  27.5 32.5 22.0 74.5  6.9 8.1 5.5 18.6  Slash Diet Shrub-Fern  May  Vaccinium Vaccinium Pteridium Polystichum  alaskaense parvifolium aqualinum munition  0.25 0.25 0.25 0.25  65.0 51.5 48.0 18.5  16.3 12.9 12.0 4.6  .  Differem (DDM -DDM  Expected Diet DDM (%)  Observed Diet DDM (%)  50.9  55.0  + 8.1  42.3  44.8  + 5.9  39.0  42.1  + 7.9  36.6  43.7  +19.4  39.1  47.1  +20.5  45.8  59.4  +29.7  Q  O  DDM (%)  l  G  Table 3-11.  Diet  Month  Slash D i e t Shrub-Conifer  May  Timber Diet Shrub-FernLichen  May  May Timber Diet Shrub-ConiferLichen  Species  Composition  continued.  Proportion Observed of spp Diet DDM  Expected SPP DDM (%)  Rubus spectdbilis Sambucus racemosa Vaccinium parvifolium Thuja plicata  0.25 0.25 0.25 0.25  35.5 77.5 51.5 58.0  8.9 19.4 12.9 14.5  Vaccinium parvifolium Vaccinium alaskaense Polystichum munitum Alectoria sarmentosa  0.25 0.25 0.25 0.25  59.5 58.0 24.0 50.0  14.9 14.5 6.0 12.6  Gaultheria shallon Thuja plicata Tsuga heterophylla Alectoria sarmentosa  0.25 0.25 0.25 0.25  15.0 45.5 32.0 50.5  3.8 11.4 8.0 12.6  'Expected c o n t r i b u t i o n to t o t a l d i g e s t i b i l i t y  = proportion of d i e t x measured  Expected Diet DDM (%) e  Observed D i f f e r e n c e (DDM -DDM )/ Diet DDM DDM (%) (%) 0  Q  e  e  55.7  60.9  + 9.3  48.0  61.2  +27.5  35.8  45.1  +26.0  digestibility.  149  apparent, but may  be  related to the particular combination of  conifer  species some of which are known to contain essential oils inhibitory to rumen microbes (Oh et a l . 1968). variation in DDM  There were no consistent patterns of  of diets collected in forested compared to cutover areas.  The number of observations obtained did not permit statistical comparison of the differences between expected and observed DDM proportion (75%)  of cases in which DDM  of diets.  The high  of diets exceeded expected levels  based on DDM  of individual species suggests the presence of an enhancement  effect.  most likely mechanism for this effect is that within  The  the  variety of microbe types present, some are better able to attack certain plant  species,  and  in so doing provide nutrients which other types can  utilize and so enhance their activity.  An additional series of DDM determine i f increasing Alectoria  evaluations of mixtures was  carried out to  the proportion of a highly digestible  sarmentosa, progressively  enhanced DDM  species,  over expected values  based on proportional digestibilities of diet components.  Results of this series of tests are presented in Table 3-12. analysis  of variance indicated  Statistical  that amounts of increased digestibility  were significantly different (p < 0.0001) between diets with differing proportions of A. sarmentosa. The interpretation of this finding is that not only is DDM  of mixtures greater than expected from DDM  species, but also that DDM of A,  of individual  of diets Is further enhanced as the proportion  sarmentosa in the diet increases.  This finding suggests that in  winter when most use of A. sarmentosa occurs, i t s presence in the diet may improve the degree to which the entire diet is utilized.  Table 3-12. Dry matter d i g e s t i b i l i t i e s of forage mixtures containing i n c r e a s i n g proportions of Aleotovia March 1974. Species Composition Diet 1  Diet 2  Diet 3  Diet 4  Observed Spp Diet P r o p o r t i o n DDM (%)  Expected Spp DDM (%)  Thuja plicata Gaultheria shallon Blechnum spicant Alectoria sarmentosa  0.25 0.25 0.25 0.25  54.5 34.0 36.5 82.0  13.6 8.5 9.1 20.5  Thuja plicata Gaultheria shallon Blechnum spicant Alectoria sarmentosa  0.20 0.20 0.20 0.40  54.5 34.0 36.5 82.0  10.9 6.8 7.3 32.8  Thuja plicata Gaultheria shallon Blechnum spicant Alectoria sarmentosa  0.167 0.167 0.167 0.501  54.5 34.0 36.5 82.0  9.1 5.7 6.1 41.1  Thuja plicata Gaultheria shallon Blechnum spicant Alectoria sarmentosa  0.143 0.143 0.143 0.572  54.5 34.0 36.5 82.0  7.8 4.9 5.2 46.9  1  Expected Diet DDM (%)  Observed D i e t DDM (%)  sarmentosa,  2  Difference (%)  51.7  54.6  + 5.5  57.8  65.4  +13.0  62.0  68.3  + 9.9  64.8  75.0  +15.7  1  Expected c o n t r i b u t i o n t o t o t a l d i g e s t i b i l i t y = p r o p o r t i o n of d i e t x measured d i g e s t i b i l i t y  2  Mean of 4 r e p l i c a t e s  3  D i f f e r e n c e s between l e v e l s s t a t i s t i c a l l y s i g n i f i c a n t a t (p _ 0.0001)  o  3  SUMMARY - DIGESTIBILITY, NUTRIENT AND  D i s t i n c t seasonal ures  and  were  generally (Short creased fibre the  related  follow  et  patterns  from s p r i n g components  spring  were observed i n most n u t r i e n t and  to  the  phenological  those observed  a l . 1971,  1975, to  of  stage of  the  the  Dry  the  process  Results  f o r e s t types  matter  f a l l - w i n t e r season, r e f l e c t i n g during  f i b r e meas-  plant.  i n s i m i l a r s t u d i e s i n other  Whelan e t a l . 1971).  which occurs  period  FIBRE CHARACTERISTICS  content i n -  the  change i n  of m a t u r a t i o n .  r a p i d e a r l y growth, woody browse s p e c i e s  During have  dry  matter c h a r a c t e r i s t i c s s i m i l a r to herbaceous p l a n t s  (Cushwa e t a l . 1970).  Shoot  associated  growth may  cessation  of  (Isenberg  1963).  dry  matter  be  growth  completed by is  Short  content  et  a l . (1975) documented a s i m i l a r i n c r e a s e with  tion  of  new  l e v e l s were h i g h e s t growth  in  the  spring.  In  at  normally increases other  time,  development of  cell  apparent  walls  a number  in of  States.  Notable ferns.  exceptions Levels  of  to  tissue.  this  lignin  contradiction, since  w i t h m a t u r a t i o n of p l a n t  initiapattern  were  lignin  high  content  It i s possible  that  changes i n chemical composition were o c c u r r i n g a t t h i s time i n f e r n s  and  e i t h e r i n f l u e n c e d DDM  for  lignin.  of  an  of  i n most s p e c i e s a t the time o f  i n A l e c t o r i a sarmentosa and this  seasonal  United  occurred ferns  lignification  this  thickening  associated  and  with  a  browse s p e c i e s i n the s o u t h e a s t e r n  Digestibility  e a r l y summer and  d i r e c t l y or i n some manner a f f e c t e d the a n a l y s i s  Temporal changes i n forage  q u a l i t y parameters were g e n e r a l l y  l e s s e r magnitude i n e v e r g r e e n than i n deciduous s p e c i e s .  nent l e v e l s remained r e l a t i v e l y constant species.  F i b r e compo-  throughout the y e a r i n c o n i f e r o u s  L e a f drop i n shrubs or dieback of above ground p o r t i o n s of herbs  152  are obvious f a c t o r s i n f l u e n c i n g the n u t r i e n t l e v e l s i n t h e s e p l a n t t y p e s . Mineral  c o n t e n t was  n o t measured i n t h i s  s t u d y but  has  undergo l a r g e changes w i t h l e a f a b c i s s i o n ( S h o r t e t al. i n f l u e n c e d DDM  been shown t o  1966) and p r o b a b l y  levels.  A crude p r o t e i n c o n t e n t o f 7% i s r e q u i r e d f o r f o r a g e s t o meet deer maintenance  needs ( D i e t z 1965).  Among f o r a g e t y p e s examined i n t h i s  f e r n s had y e a r - l o n g v a l u e s g r e a t e r t h a n 7%, f o l i u m exceed and As  7% crude p r o t e i n l e v e l s  shrubs and E p i l o b i u m a n g u s t i -  i n s p r i n g and  noted  earlier, to  the p l a n t species s e l e c t e d i n t h i s  r e c e i v e h i g h l e v e l s o f use  content  A l t h o u g h t h e s e may  have c o n t r i b u t e d t o y e a r - r o u n d  selected  by  comprised patterns  of are  i n Table deer, major  3-13  are  s t u d y examined i n d e t a i l , t h e y  winter  The  o f the  "diet"  c o n t r a s t e d t o the  characteristics  o f the  "menu"  available.  more d i g e s t i b l e  pattern i s similar  period.  Deer  readily-digestible  appeared  cell  T h i s i s suggested  characteristics  q u a l i t y than the average a v a i l a b l e .  items.  undoubtedly  the  species  i n which  examined, i t i s c l e a r  substantially  as  food h a b i t s t o a l e s s e r  i m p o r t a n t s h o r t - t e r m i n f l u e n c e s on deer n u t r i t i o n . data  those  were f e d upon a t v a r i o u s times o f the y e a r .  degree t h a n t h e s p e c i e s t h i s  the  s t u d y were  Many o t h e r s p e c i e s w i t h a wide  range o f n u t r i e n t  was  lichens  a t some time d u r i n g the y e a r  i n d i c a t e d by a n a l y s e s o f rumen c o n t e n t s .  by  summer, and  c o n i f e r s c o n t a i n e d l e s s t h a n t h i s l e v e l throughout most o f the y e a r .  observed  had  study,  When a c t u a l  t h a t deer  forage  select  I n the case o f DDM, than  the  f o r crude t o be  c o n t e n t s , and  forages of higher the d i e t s e l e c t e d  "menu" o f p o t e n t i a l protein  selecting as  consumption  except  f o r high  a result,  fibre  forage  i n the levels content  ADF, ADL) o f f o r a g e s consumed was l e s s t h a n t h a t o f t h e "menu."  fallof  the (NDF,  Table 3-13. Seasonal n u t r i e n t composition and cejLl components of primary forages consumed by b l a c k - t a i l e d deer ("diet") compared to major forages a v a i l a b l e ("menu") . Spring Nutrient Component (%) Dry matter Crude p r o t e i n Dry matter d i g e s t i b i l i t y  Summer  Fall-Winter  Annual  "diet"  "menu"  "diet"  "menu"  "diet"  "menu"  "diet"  "menu"  20.4 21.6 58.2  32.0 12.8 41.0  24.1 13.9 70.5  35.2 8.0 43.8  40.2 4.8 56.9  38.5 6.4 42.8  28.2 13.4 61.9  36.6 7.9 42.7  80.4 19.6 20.1 7.4 12.7 1.2  60.2 39.8 35.6 17.0 18.6 4.3  72.8 27.2 22.4 3.3 19.1 9.3  54.9 45.1 37.6. 18.4 19.2 7.4  57.2 41.2 25.3 9.3 16.6 15.5  52.9 47.1 36.7 16.8 22.1 10.5  70.1 29.3 22.6 6.7 16.1 8.7  54.9 45.1 36.7 17.4 19.9 8.5  C e l l Component (%) C e l l contents Neutral-detergent f i b r e Acid-detergent f i b r e Acid-detergent l i g n i n Cellulose Hemicellulose  Combination of p l a n t species making up m a j o r i t y of forage consumed. Values are weighted according to t h e i r percent Importance Value (IV) as determined i n rumen -content analyses. Diets c o n s i s t o f : Spring - Epilobium angustifolium IV - 41, Rubus spp. IV - 26, Cornus canadensis combined IV = 79% of s p r i n g d i e t . -  IV .- 12,  Summer - E. angustifolium IV - 66, Rubus spp. IV - 12, combined IV = 78% of summer d i e t . F a l l - W i n t e r - Gaultheria shallon IV = 24, E. angustifolium combined IV = 59% o f f a l l - w i n t e r d i e t .  IV = 23, Alectoria  sarmentosa IV - 12,  V a r i a t i o n s i n sample s i z e s and l a c k of r e p l i c a t e s i n rumen content analyses prevented comparisons of " d i e t " and "menu."  statistical  Combination of forage species examined. "Menu" i s the same i n each season and i n d i c a t e s average values for species group which includes 6Y ehallon Vaccinium alaskaense, V. parvifolium, Pseudotsuga menziesii, Tsuga heterophylla, Thuja plicata, A. sarmentosa, E. angustifolium, Blechnum spicant and Polystichum muni turn. s  154  Differences  between nutrient and fibre  characteristics  of "diet" and  "menu" were least pronounced during the fall-winter season. This probably reflects the decreased forage quality associated with plant maturation and leaf abcission and the reduced availability of herbaceous species. In the case of crude protein, levels in the "diet" were less than those in  the "menu," apparently a result  pf the relatively  high use of  Alectoria sarmentosa, which contains less than 2% crude protein. Dietary protein levels are probably of lesser importance to deer during winter than in other seasons and i t is possible that i t is more advantageous for deer  to select  for high energy  foods at this time.  Deer typically  catabolize body protein in winter to meet protein needs (Ullrey et a l . 1968) as evidenced by the weight losses which normally occur (Nordan et al. 1968).  Comparisons of the same species collected i n forested stands and cutover areas did not show consistent patterns in forage quality related to area of collection.  For example, a species might be more digestible in the  forest one month and more digestible in a cutover area the following month.  A number of factors are probably responsible for this variation.  Timber stands varied i n amount of canopy closure, with randomly occurring openings.  The sampling procedure employed did not select for or against  plants growing in openings. differences,  which  Probably more important were micro-climatic  influenced  phenological development of the plants  between some cutover and timbered areas. Both timing of growth phase and growth habit were affected by local climatic conditions. Gaultheria shallon in forested areas produced  For example,  few or no flowers while  plants in cutovers flowered profusely. In areas where samples were col-  155  lected, production of new approximately  foliage in this species in forests was delayed  2-3 weeks from that observed in cutovers.  It seems likely  that differences in degree of flowering and phenological development of this magnitude could easily result in the variation in nutrient levels and  DDM  observed between samples collected  from forested and  cutover  areas.  Digestibility of forage mixtures which represented deer diets was up to 30% greater than expected based on digestibilities of individual components.  Enhancement of microbial growth and fermentation capacity asso-  ciated with a variety of substrates is the probable mechanism for this effect. suggested  Microbial adaption by  reduced  to  capacity  seasonal of  forage  composition  rumen microbes  to  was  also  ferment species  mixtures during seasons outside their normal period of use.  Overall digestibilities of mixtures increased beyond expected levels as increasing amounts of Alectoria sarmentosa were added, suggesting that presence of this highly digestible species enhances the degree to which the entire diet is utilized.  This observation could help explain the  apparent preference deer show for this species during winter periods when quality of available forage is generally low.  Examination of rates at which dry matter digestibility occurred in vitro indicated  that most species  were fully  digested  (90%)  in 24 hours.  Several species reached this level in 12 hours. Alectoria sarmentosa was an exception (46% DDM  in 24 hours).  This observation suggests that most  species will be fully utilized by deer since reported rumen turnover times range from 14 to 33 hours.  156  Alectoria sarmentosa contained lower total fibre levels and hemicellulose made up a larger proportion of total fibre than in other species analyzed. Hemicellulose is the most digestible portion of total fibre and likely has  an important  influence on the high digestibilities  observed in  Alectoria sarmentosa.  Dry matter disappearance in a r t i f i c i a l saliva solution provided a rough measure of soluble cell components, which generally paralleled seasonal changes in digestibility.  This technique appears to have potential as a  simple estimator of DDM.  RELATIONSHIPS BETWEEN FORAGE CHARACTERISTICS  Nutritional indicators for use in estimating value of deer forage plants are of interest to wildlife managers.  DDM is generally accepted as a  reliable integrator of a range of forage characteristics, but requires a relatively involved analytical procedure.  Objective 2 of this study was  directed at exploring relationships between forage characteristics which might facilitate estimates of nutritional values.  Correlation matrices indicating the significant (p < 0.05) relationships between measures of forage characteristics are presented in Tables 3-14, 3-15  and 3-16 for forage types and Tables 3-17, 3-18 and 3-19 for indi-  vidual species.  Generally, measures which reflect increasing maturity  and lignification of plant tissue (i.e. dry matter content, NDF, ADF and ADL) were negatively correlated with crude protein and DDM. This negative influence of fibre on DDM in particular, has been observed by other in-  T a b l e 3-14. C o r r e l a t i o n c o e f f i c i e n t s o f n u t r i e n t and f i b r e c h a r a c t e r i s t i c s o f forage types. s i g n i f i c a n t ( p f 0.05) v a l u e s a r e l i s t e d . C o r r e l a t i o n s a r e f o r mean annual n u t r i e n t l e v e l s . Correlation of;  SHRUBS 63)  CONIFERS (n «= 62)  -0.66  -0.47  -0.96  -0.52  0.54 0.40  0.93 0.91  0.51  (n =  FORBS (n - 5)  Only  FERNS (n = 36)  Dry Matter w i t h : CPU. DDM NDF ADF "ADL  2  3  Crude P r o t e i n w i t h : DDM NDF ADF ADL  0.58 -0.26  -0.41 -0.38 -0.47 -0.44  DDM w i t h : NDF ADF ADL  -0.44 -0.51 -0.64  -0.26 -0.42  NDF w i t h : ADF ADL  0.59 0.75  0.53  0.55  ADF w i t h : ADL '  0.49  .0.61  Number o f measurements. Crude p r o t e i n . ,  3  C o e f f i c i e n t s f o r c e l l contents same as f o r NDF except s i g n i s reversed ( c e l l content -= 1 - NDF).  Table 3-15. C o r r e l a t i o n c o e f f i c i e n t s o f n u t r i e n t and f i b r e c h a r a c t e r i s t i c s of forage types. values ( p f 0.05) a r e l i s t e d . C o r r e l a t i o n s are f o r mean annual n u t r i e n t l e v e l s . Correlation of:  SHRUBS Forested  Only s i g n ii f i c a n t  CONIFERS  ( 3 1 ) Cutover (32) 1  Forested  (31)  FERNS  Cutcver (31)  Forested (18) Cutover (18)  Dry Matter w i t h : CPR  2  DDM NDF ADF ADL  -0 67  3  -0.67  -0.56  0.44  0.63 0.40  0.36 0.38  -0.41  -0.40 -0.46  -0.52  -0.52  0.64  0.73  Crude P r o t e i n w i t h : DDM NDF ADF ADL  0.73  0.50 -0.45  DDM w i t h : NDF ADF ADL  -0.57 -0.74 -0.84  -0.40 -0.70  NDF w i t h : ADF ADL  0.39 0.72  0.64 0.64  0.57  0.54  0.71  ADF w i t h : ADL  0.57  0.70  Number of measurements. "Crude p r o t e i n . C o e f f i c i e n t s f o r c e l l contents same as f o r NDF except sign i s reversed  ( c e l l content = 1  NDF) .  Table 3-16. C o r r e l a t i o n c o e f f i c i e n t s of n u t r i e n t and f i b r e c h a r a c t e r i s t i c s of forage types. (p 1 0.05) are l i s t e d . C o r r e l a t i o n s are f o r seasonal n u t r i e n t l e v e l s . Correlation of: Dry Matter w i t h : CPR  DDM NDF ADF ADL  CONIFERS  SHRUBS Fall-Winter (42)  Spring (12)  Summer (16)  Fall-Winter (42)  -0.66  2  Only s i g n i f i c a n t values  -0.81 -0.53 -0.78  3  44  FERNS  Spring  Summer  (12)  (14)  -0.77  -0.80  0.69 0.70 0.83  0.73  -0.63 -0.62 -0.66  -0.63 -0.58  Fall-Winter (24)  Spring (8)  -0.61 0.62 0.47  Summer (8) .73  Crude P r o t e i n w i t h : DDM NDF ADF ADL  0.86  0.53  0.43 0.61  DDM w i t h : NDF ADF ADL  -0.80 -0.82 -0.94  0.70  0.73  -0.83  NDF With: ADF ADL  0.81  0.57  0.76 0.83  0.60 0.79  0.81  0.94  ..  ..  0.80  0.79  ADF w i t h : ADL  -0.61  ..  ..  'Number of measurements. Crude p r o t e i n . C o e f f i c i e n t s f o r c e l l contents same as f o r NDF except s i g n i s reversed ( c e l l content = 1 - NDF).  0.74  ..  0.80  2  3  '!  Table 3-17. C o r r e l a t i o n c o e f f i c i e n t s of n u t r i e n t and f i b r e c h a r a c t e r i s t i c s o f shrub species. values ( p _ 0 . 0 5 ) are l i s t e d . C o r r e l a t i o n s are f o r mean annual n u t r i e n t l e v e l s . Correlation of:  Gaultheria Forested  shallon  (11)' Cutover (11)  Vaooinium Forested (11)  alaskaense Cutover (11)  Dry Matter w i t h : CPR DDM NDF ADF ADL  2  88  -0 72  3  -0.73 -0.78  Only s i g n i f i c a n t  Vaooinium Forested ( 9)  parvifolium Cutover (10)  82  -0 75  -0 80  0.71 -0.69  0.80 -0.67  -0.79  -0.90 -0.87 -0.84  -0.84  0.80  Crude P r o t e i n w i t h : DDM NDF ADF ADL  -0.70  0.77  DDM w i t h : NDF ADF ADL NDF w i t h : ADF ADL  0.75 0.77  0.79 0.88  0.73 0.93  0.82  ADF w i t h : ADL . 2  0.86  Number of measurements. Crude p r o t e i n . C o e f f i c i e n t s f o r c e l l contents same as f o r NDF except sign i s reversed  0.88  (cell  content  NDF).  -0.79 -0.64 -0.91  Table 3-18. C o r r e l a t i o n c o e f f i c i e n t s of n u t r i e n t and f i b r e c h a r a c t e r i s t i c s of c o n i f e r species. v a l u e s ( p f 0 . 0 5 ) are l i s t e d . C o r r e l a t i o n s are f o r mean annual n u t r i e n t l e v e l s . Correlation of:  Pseudotsuga  Forested(10)'  menziesii  Cutover(10)  Thuja  plioata  Forested ( H ) Cutover ( n )  Only s i g n i f i c a n t  Tsuga  heterophylla  Forested (10) Cutover (10)  Dry Matter w i t h : CPR  DDM NDF ADF ADL  2  3  64  -0.81 0.68 0.76 0.94  -0.66  -0.67 0.63 -0.79  0.83  Crude P r o t e i n w i t h : DDM NDF ADF ADL  0.63  -0.77 -0.74  -0.62  -0.64  -0.70  DDM w i t h : NDF ADF ADL  -0.64 -0.96  NDF w i t h : ADF ADL  0.62  0.88  ADF w i t h : ADL 2 3  Number of measurements. Crude p r o t e i n . C o e f f i c i e n t s f o r c e l l contents same as f o r NDF except sign i s reversed  ( c e l l content = 1 - NDF).  Table 3-19. C o r r e l a t i o n c o e f f i c i e n t s of n u t r i e n t and f i b r e c h a r a c t e r i s t i c s of forbs and ferns. values (p_0.05) are l i s t e d . C o r r e l a t i o n s are f o r mean annual n u t r i e n t l e v e l s . Correlation of:  Epilobium  angustifolium  Cutover(5)  Blechnum Forested (9)  1  spicant  Only s i g n i f i c a n t  Polystichum  Cutover (9)  Forested (9)  munitum  Cutover (9)  Dry Matter w i t h : CPR DDM NDF ADF ADL  2  3  -0.96 0.93 0.91  -0.73 0.68  75  -0.95  -0.70 0.87  -0.92  Crude P r o t e i n w i t h : DDM NDF ADF ADL  -0.87  -0.71  0.83 0.90  DDM w i t h : NDF ADF ADL  -0.88  NDF w i t h : ADF ADL  0.78  ADF w i t h : ADL Number of measurements. Crude p r o t e i n . " C o e f f i c i e n t s f o r c e l l contents same as f o r NDF except sign i s reversed  0.89  2  ( c e l l content = 1  NDF).  163  vestigators (Urness and McCulloch 1973, Robbins et a l . 1975, Whelan et al.  1971) for a variety of forage species.  Skeen (1974) subtracted  content of soluble carbohydrates from nitrogen-free extract to determine an undefined fibre component which he observed to be negatively correlated to crude protein and DDM.  Cell contents of forages, calculated by sub-  tracting NDF from 1 are highly digestible and well correlated in a positive fashion to DDM (Short and Reagor 1970, Van Soest 1967). In the data presented here, correlation coefficients between cell contents with other measures are the same.as those indicated for NDF, except that the sign is reversed.  The stage of growth of the plant appears to have an important effect on the relationship of DDM to various fibre measures. For example, Torgeson and Pfander  (1971), observed a positive relationship between cellulose  content and DDM of a variety of forages i n summer, and a negative relationship in the same plants in winter.  They attributed this finding to  the increasing lignification associated with plant maturation which decreased the digestibility of cellulose.  Short et a l . (1973) also noted  that fibre-DDM relationships were different in immature than in mature woody shoots.  Similar  seasonal variations  in degree  of correlation  occurred i n the present study (Table 3-16) with varied patterns between forage types.  The negative correlation of various fibre components and DDM" was relatively consistent but not always statistically significant among forage types and species (Tables 3-13 to 3-18), and was most apparent in conifers and ferns.  This variation among forage types has been observed by others  164  (Short and Reagor 1970, Short et a l . 1974) who attribute i t to the different levels of lignin in varied plant types.  They observed that as the  cell wall content of herbages, which contain low levels of lignin, increased, DDM also increased. The opposite effect occurred in woody twigs, in which lignin concentrations in cell walls increase with maturation. Another apparent reason for this difference between forage types is that lignin and carbohydrates are chemically bonded in a different way in woody plants compared to herbs (Pew and Weyna 1962, cited in Short et al. 1972). In the present study, ferns behaved much like woody plants, having high levels of lignin, NDF and ADF, which were negatively correlated to DDM. Levels of lignin were high in ferns in spring, when most other types had their lowest lignin levels.  It is likely that other differences in the  chemical composition of ferns, which were not detected here, are responsible for these variations in fibre measures from other types.  Significant  correlations which occurred between forage characteristics  were not high in most cases, possibly reflecting the nature of the samples which in most instances included both leaves and twigs.  Short et a l .  (1975) analyzed twigs and leaves separately for a number of browse species and observed that correlations between forage characteristics were usually in the same direction but the degree of correlation was often different. They attributed a reduced  correlation for leaves compared to twigs as  perhaps related to the presence of waxes, oils, resin or other leaf components that affect either digestibility or the r e l i a b i l i t y of detergentfibre analyses or both.  These factors may have also been responsible for  the low coefficients observed for most of the significant correlations in this study.  165  While some relationships were consistent among most species, correlation coefficients were generally reduced when species were examined i n combination (i.e. types) (Tables 3-14, 3-15 and 3-16). This reduction comes about as a result of the different degree of relationship among various nutrient measures in individual species. individual  Correlation coefficients for  forage species collected in timbered  presented in Tables 3-17, 3-18 and 3-19.  and cutover areas are  Correlations varied depending  on the plant species or type but were generally higher and more consistent for individual species than for plant types.  There were no significant  correlations between nutrient characteristics i n Alectoria sarmentosa, probably a result of i t s chemical composition which differs from that of other plant types.  The negative relationship between fibre components  and DDM occurred much more frequently in plants from cutovers than from forested areas.  This relationship did not appear to be related to total  amounts of fibre since species collected i n forested areas were almost always higher in fibre components (NDF, ADF, ADL) than those collected in cutovers (Table 3-9). For reasons not apparent, fibre content had a much more consistent relationship to DDM in plants growing in cutovers than in forested areas.  Perhaps growing conditions were more uniform i n the cut-  overs, as amount of light varied, both temporally and spatially, in forest in relation to the amount of overhead canopy. Correlation patterns were variable among species, as can be seen i n the two Vaccinium species which showed  consistent negative  Gaultheria absent.  relationships  shallon, the other shrub  of fibre  evaluated, this  to DDM,  while i n  relationship was  This variability among species indicates that evaluations made  on a type level (e.g. shrubs) are not likely to provide a reliable idea of fibre-DDM relationships.  166  Following  up  nutrient and (Short  et  multiple  the  apparent relationships indicated by  fibre characteristics, and  a l . 1973) regression  indicating useful was  employed  correlations  of  reports of other investigators predictor  variables, stepwise  to explore predictive  between these characteristics and in vitro DDM.  relationships  The regression technique  employed a minimum level of inclusion (< 0.05), thus only those variables with significance at this level or below were included in the equation. Equations and their statistical significance for individual forage species are listed in Table 3-20.  Regressions are for annual values as limited  sample sizes prevented the examination of seasonal values or separate patterns  for plants from forested and cutover areas. As Table 3-20  indi-  cates different nutrient characteristics were important in predicting in individual species. content and to DDM  DDM  Within shrubs, crude protein, dry matter, cell  acid-detergent lignin each showed significant relationships  although generally higher, r^ values were associated with the c e l l  contents measure. Short et a l . (1973) observed a similar relationship in summer twigs  of  the  detergent lignin and conifers.  combined  group  crude protein had  of species  they studied.  Acid-  a close relationship to DDM  in  In ferns, crude protein level can be used to predict digesti-  b i l i t y , with an inverse relationship occurring between these two measures.  In summary, examination of the relationships between forage  character-  istics indicates that substantial variability exists. Thus, two measures which were highly  correlated  in a species  collected in cutovers  exhibit a poor relationship in the same species Correlations  generally  may  from forested areas.  improved going from broad taxonomic level (e.g.  type) to more specific levels (e.g. species).  Variability in degree of  Table 3-20. Regressions of i n v i t r o d i g e s t i b i l i t y (DDM) values (y) on dry matter (DRY), crude protein (CPR), c e l l content ( C e l l C), acid-detergent f i b r e (ADF) and acid-detergent lignin(ADL). DDM values predicted are mean annual l e v e l s .  Species  Area  Gaultheria  shallon  C  Vaccinium  alaskaense  F  Regression Equation  a  y y =  43.95 87.29  y y =  19.50 63.23  -  -  2.31 (CPR) 0.88 (DRY) - 4.11 (CPR)  Coefficient of Determination  —  [Fry—  0.05 0.05  0.49 0.77  0.79 (DRY)  0.04 0.01  0.60 0.61  + 1.76 (CPR)  -  Significance Level of F Test  C  y = -39.07  + 1.55 ( C e l l C)  0.01  0.82  Vaccinium  alaskaense a parvifolium  F  y =  4.11  + 0.90 ( C e l l C)  0.01  0.70  Vaccinium  parvifolium  C  y = y  82.87 9.55  Vaccinium  Pseudotsuga  Thuja  menziesii  plicata  C  —2.47  (ADL)  0.01 0.01  0.83 0.63  —5.3  (ADL)  + 0.74 ( C e l l O  131.36 y y = 50.5  + 3.53 (CPR) - 0.31 ( C e l l C)  0.01 0.05  0.93 0.66  23.72 50.5  + 5.56 (CPR) + 3.53 (CPR) - 0.31 ( C e l l C)  0.01 0.05  0.77 0.65  0.05  0.79  0.05  0.50  F  y y  —  Blechnum  spicant  F  y =  55.17  -  Blechnum  spicant  C  y  56.9  —1.4  Area designation: F = Forested;  C  cs  Cutover  1.74 (CPR) (CPR)  168  correlation of forage characteristics was high between different types, reflecting their variable composition.  Regression analysis identified several forage characteristics which significantly  influenced DDM.  Variability  in importance  of particular  characteristics was high, depending on plant species and area of collection.  The analysis did point out several characteristics, notably ADL  and cell contents, which have high potential as predictors of DDM for some species.  RUMEN CHARACTERISTICS  LITERATURE REVIEW  Rumen F i l l and Dry Matter Content  The proportion of body weight made up by rumen contents varies with degree of  rumen f i l l and the proportions of dry matter and water in the rumen  contents (Bailey 1969). Rumen f i l l varies with total food consumption, time since eating and digestibility and consistency of the food (Short 1969).  Rumen contents of white-tailed deer with a f u l l rumen normally amount to about 6 to 7 percent of body weight and contain dry matter equal to about 1 to 2 percent of body weight (Bailey 1969).  169  The  bulkiness and moisture level of the diet influence rumen f i l l as  observed by Short et a l . (1969) and Short (1975). rumen dry matter  In the f i r s t study,  content was 26.8 percent on range where acorns con-  stituted a large part of the f a l l diet, compared to 14.6 percent on range where acorns were not available. in  In the latter study, similar differences  dry matter of rumen contents were observed between seasons, with high  values in September when acorns were available.  Since acorns are high in  dry matter, but also highly nutritious as a result of their high content of  fats and easily-digested carbohydrates, deer obtain high levels of  nutrients from a diet of acorns.  In the case of woody or fibrous mate-  rials, inadequate levels of nutrient intake may occur because of low d i gestibility and turnover rates of rumen contents.  With improved quality of feed, forage intake rates increase as shown by Ullrey et a l . (1972) who observed significantly greater daily dry matter intake  of northern white  cedar  (Thuja  occidentalis),  than  of aspen  (Populus grandidenta), an inferior forage, by white-tailed deer in winter. Low moisture  contents of forage in winter result in higher rumen dry  matter content and higher rumen f i l l as shown i n moose (Alces alces) by Gasaway and Coady (1974).  These investigators and others (Weston and  Hogan 1968) presented data indicating that increased rumen f i l l was i n part due to reduced digestion of dry matter, probably as a result of reduced  digestibility  and turnover  of woody  forage.  Hungate (1975)  pointed out that passage rate of less digestible forage in ruminants is low, resulting in greater rumen f i l l which i n turn reduces forage intake rates.  Ammann et a l . (1973) observed in white-tailed deer that as d i -  gestibility of forage declines, intake increases to the point where the  170  animal is eating to the maximum capacity of the digestive tract. Beyond this point, reduced rates of passage associated with declining digestib i l i t y limit further intake.  Rumen f i l l was measured in the present study to determine i f a similar pattern was occurring relative to seasonal forage conditions.  Dry matter  levels of rumen contents were examined to determine their relationship to seasonal patterns of forage use and quality.  Rumen Crude Protein Content  Crude protein level of rumen contents indirectly reflects relative quality of forage ingested  (Klein and Standgaard 1972). Klein (1962) found that  in spring and summer, black-tailed deer selected the plants highest protein levels as substantiated rumen contents.  containing  by analyses of both forage and  He was able to separate two deer ranges of different  quality using this technique.  Within the forage species available, deer are able to select the individual plants or plant parts richest in nitrogen (Longhurst et a l . 1968, Swift 1948). of  forage  Analyses of gross rumen contents indicate combined levels  and microbial  protein.  Analyses of washed rumen contents  probably indicate minimum protein levels since soluble protein and amino acids which are readily digested may be lost (Gasaway and Coady 1974), Seasonal variations in range forage value for white-tailed deer have been documented by Kirkpatrick et a l . (1969) using chemical components, i n cluding protein level, of rumen contents.  171  In the present study, crude protein level of rumen contents was measured to examine i t s relationship to feeding patterns and forage protein values as determined seasonally.  METHODS  Dry Matter Content  A sample of approximately 100 g of rumen contents, made up of several subsamples  from different portions of the rumen, was taken at the time  rumen inoculum was collected for in vitro analyses. Dry weight of this sample was determined following drying at 60°C for 24 hours i n a forceddraft oven.  Dry matter content as a percentage of wet weight was then  calculated.  Rumen F i l l  Total weight of the rumen and i t s contents was determined prior to sampling for food habits, dry matter and i n vitro analyses. Weight of rumen contents was determined by subtracting weight of the washed rumen tissue from total rumen weight.  Rumen f i l l was calculated as a percentage of  the live weight of the animal made up by wet weight of rumen contents.  Crude Protein Content  Following dry matter determination of a sample of rumen contents, the sample was stored in a sealed glass jar. Nitrogen content was subse-  172  quently  determined  Sommers  (1973).  using  the  micro-Kjeldahl procedure  Crude protein  was  calculated  using  of Nelson  and  the conversion:  percent nitrogen x 6.25 = percent crude protein.  RESULTS AND DISCUSSION  Dry Matter Content  Seasonal  levels  cutover and  of dry matter in rumen contents of deer collected in  forested areas are presented  matter contents are listed in Table 3-22 Figure 3-10.  in Table 3-21.  Monthly dry  and graphically displayed in  On a seasonal basis, dry matter was lowest in spring and  highest in fall-winter with intermediate values in summer. Dry matter levels in fall-winter were significantly greater than in the other two seasons.  A  similar  pattern was  documented for white-tailed  deer by  Kirkpatrick et a l . (1969) except they showed high dry matter levels in f a l l associated with extensive use of acorns.  Short et a l . (1969) ob-  served similar high dry matter levels in rumens of deer consuming acorns. Dry matter levels ranged from 12.8 (±0.4) percent in spring to 16.0 (±0.6) percent in fall-winter, levels very similar to those observed for moose in Alaska (spring - 12.7 percent, winter - 15.9 percent) by Gasaway and Coady (1974).  Seasonal changes in dry matter content reflected the change  which occurs in forage plants from a condition of succulence in new tissue in spring to a more fibrous woody condition with low moisture content in fall-winter.  Table 3-21.  Seasonal l e v e l s of rumen f i l l , dry matter and crude p r o t e i n contents of rumens of b l a c k - t a i l e d deer c o l l e c t e d i n f o r e s t e d and cutover areas.  Rumen F i l l n  1  X  (S.D.)  Rumen Crude P r o t e i n - (%)  Rumen Dry Matter - (%)  - (%) n  (S .D.)  n  13 .6 (0.4) 12 .8 (1 .3) 12 .9 (1 • 2 )  2 10  X  X  (S.D.)  Spring Forested Cutover Forested and Cutover  2 10 12  10.9 (3.9) 7.6 (2.2) 8.2 ( 2 . 6 )  a  2 10 12  32. 4 (5.7) 39. 9 (2.7)* 38. 7 ( 4 . 2 ) a  3  Summer Fo res ted Cu Cover Forested and Cutover  • _  _  15 -  10.8  8 21 29  13.3 (2.1) 13.0 (3.2) 13.1 ( 2 . 9 )  10 46 56  12.8 11.1 11.4  (2.0)  b  _  14 -  27. 7 ( 9 . 3 )  16 .0 (1. .4) 14 .6 (1. • h 14 .9 (1. .9)  6 21 27  13. 7 (1.8) 18. 5 (5.5)* 17. 4 ( 5 . 3 )  15 .4 (1. ,6)* 13 .8 (1. .7) 14 .0 (1. .8)  8 45 53  18. 4 (9.1) 26. 1 (10.6)i 24. 9 (10.7)  15 -  13 .3 (1, ,0)  6 21 27  8 46 . 54  a  b  Fall-Winter Forested Cutover Forested and Cutover  c  9)  b  c  Annual Forested Cutover Forested and Cutover  1  (2.5) (3.3) (3.2)  Runien f i l l = weight of rumen contents expressed, as a percentage of body weight.  * I n d i c a t e s s t a t i s t i c a l s i g n i f i c a n c e (p < 0.05); s u p e r s c r i p t i s beside the higher value i n f o r e s t e d and cutover comparisons. c  I n d i c a t e s s t a t i s t i c a l s i g n i f i c a n c e as determined by a n a l y s i s of v a r i a n c e . Seasonal means for combined f o r e s t e d and cutover areas having a common s u p e r s c r i p t a r e not d i f f e r e n t (p < 0.05).  T a b l e 3-22.  Monthly l e v e l s of rumen f i l l and d r y matter and crude p r o t e i n i n rumen c o n t e n t s o f b l a c k - t a i i e d d e e r . V a l u e s a r e combined means f o r deer from f o r e s t e d and c u t o v e r a r e a s .  Rumen F i l l n  Rumen Dry Matter - (%)  - (%) X  (S D.)  n  X  (s  Rumen Crude P r o t e i n - (%) n  D.)  X  (S • D .)  January  3  15. 2 (3 8)  3  14 8 (1 0)  3  13 1 ( 1. 6)  February  5  15. 0 (1 1)  3  15 8 (1 3)  3  14 7 ( 2. 9)  March  7  14. 5 (2 5)  7  14 6 (2 6)  7  15 3 ( 1. 8)  April  5  9. 7 (2. 1)  5  15 3 (2 0)  5  22 4 ( 3. 6)  May  6.  8. 5 (2. 8)  6  12 4 (1 5)  6  38 9 ( 5. 7)  June  6  8. 0 (2 7)  6  13 5 (0 7)  6  38 5 ( 2. 3)  July  4  10. 2 (1 8)  4  13 2 (1 4)  4  33 7 ( 3. 7)  10  11. 1 (2 2)  10  13 3 (0 9)  10  25 3 (10. 0)  September  1  10. 5 ( -- )  1  13 5  •  October  2  2  12 2 (2 3)  2  29 7 ( 3. 0)  November  3  13 5 (0 9)  3  15 4 (1 2)  3  17 1 ( 4. 1)  December  4  12. 8 01 2)  4  15 4 (0 6)  4  14 1 ( 1. 5)  56  11 4 (3 2)  54  14 0 (1 8)  53  24 9 (10. 7)  Augus t  Annual  3  Rumen f i l l  8 6 (1  9  >  - )  -  = weight o f rumen c o n t e n t s expressed as a percentage o f body 'weight.  175  Percent  44 40 36  s  .  crude  protein  32  \  28  \  9 24 20 16  m'Slr*—-«»  dry. m a t t e r  12 8  rumen  fill  4 0 Jan  _i_ Feb  3.  a Mar  I Apr  i May  ;  ' Jun  « Jul  i Aug  L Sep  Oct  Nov  Dec  Weight o f rumen c o n t e n t s e x p r e s s e d as a p e r c e n t a g e o f body weight.  F i g u r e 3-10.  Monthly l e v e l s of rumen f i l l and d r y m a t t e r and crude p r o t e i n i n rumen c o n t e n t s o f b l a c k - t a i l e d d e e r . V a l u e s a r e combined means f o r deer from f o r e s t e d and c u t o v e r a r e a s .  176  Dry matter content of rumens from deer c o l l e c t e d i n forested areas was higher i n a l l seasons than i n deer from cutover areas (Table 3-21). ferences were not s t a t i s t i c a l l y annual  average.  significant  Dif-  (p < 0.05) except f o r the  Increased l e v e l s of dry matter i n deer from  forested  areas probably i s the r e s u l t of the greater p r o p o r t i o n of shrubs and conifers i n the d i e t of deer from these areas (Figure 3-1), even though dry matter l e v e l s i n i n d i v i d u a l species from forested areas were generally less than those i n plants from cutovers (Table 3-1).  Differences i n dry matter of rumen contents on a monthly basis were small, and  not s t a t i s t i c a l l y  s i g n i f i c a n t , probably as a r e s u l t of the small  sample sizes involved (Table 3-22).  As expected, dry matter l e v e l s during  the growing season were generally less than i n the dormant period (Figure 3-10).  Rumen F i l l  Seasonal and monthly  l e v e l s of rumen f i l l  and 3-22 r e s p e c t i v e l y . 3-10.  Patterns of monthly  Average annual rumen f i l l  percent.  are presented i n Tables 3-21 change are shown i n Figure  f o r the 56 deer samples was 11.4 (±0.4)  S i m i l a r values were reported f o r other Cervidae i n c l u d i n g Cervus  elaphus (10-14.9 percent), Dama dama (9-12 percent), Capreolus capreolus (7.0 percent) (Prins and Geelen 1971), Odocoileus hemionus (7.4 percent) (Short et a l . 1965) and Odocoileus v i r g i n i a n u s (8.0 percent) (Short e t al.  1969).  The s l i g h t l y higher values observed i n t h i s study compared to  other work w i t h Odocoileus spp. may r e f l e c t the f a c t that greater than 50 percent of the deer making up the annual sample i n the current study were  177  collected  during f a l l - w i n t e r , when l e v e l s of rumen f i l l  are generally  greatest.  Rumen f i l l  v a r i e d seasonally from a low of 7.6 (±0.7) percent of body  weight i n deer from cutover areas i n spring to 13.3 (±0.7) percent i n deer  from forested areas i n f a l l - w i n t e r  (Table 3-21).  Mean l e v e l s of  rumen f i l l  f o r deer from forested and cutover areas combined were s t a -  tistically  different  (p < 0.05) between seasons.  A s i m i l a r p a t t e r n of  v a r i a t i o n was observed i n moose by Gasaway and Coady (1974).  Increased  d i g e s t i b i l i t y and more rapid turnover of succulent forages i n spring and summer probably are the f a c t o r s responsible f o r lower rumen f i l l i n these seasons.  Short (1971) observed lower rumen f i l l i n winter i n w h i t e - t a i l e d  deer he studied, but indicated time of day of c o l l e c t i o n may have i n f l u enced these r e s u l t s ; dry matter contents were highest during the same period.  Rumen f i l l was s l i g h t l y higher ( n o n s i g n i f i c a n t l y ) i n deer from forested areas than from cutovers i n spring and f a l l - w i n t e r , probably the r e s u l t of greater use of shrubs and conifers by deer i n forested areas (Figure 3-1).  Monthly  patterns of rumen f i l l  r e f l e c t e d the increased succulence and  d i g e s t i b i l i t y of forages during the growing season, w i t h lowest l e v e l s during these months (Figure 3-10).  A low l e v e l (8.6 ± 1.3 percent) of  rumen f i l l was observed i n October; apparently since deer i n the sample were using p r i m a r i l y Epilobium angustifolium and very l i m i t e d amounts of shrubs or conifers at t h i s time (Figure 3-2).  178  Crude P r o t e i n Content  Levels  of crude p r o t e i n i n rumen contents underwent  magnitude 3-10).  both seasonally  (Table 3-21)  Levels ranged from 39.9  cutovers i n spring to 13.7 fall-winter.  Statistical  changes  of large  and monthly (Table 3-22, Figure  (±0.8) percent i n rumens of deer from  (±0.7) percent i n deer from forested areas i n comparisons of mean seasonal l e v e l s of crude  p r o t e i n f o r deer from forested and cutover areas combined showed s i g n i f i cant  (p < 0.05)  differences between a l l seasons  (Table 3-21).  Klein  (1962) recorded s i m i l a r l e v e l s (40.1 and 27.4 percent) of crude p r o t e i n i n rumens of b l a c k - t a i l e d deer from good and poor h a b i t a t s , r e s p e c t i v e l y .  Crude p r o t e i n content more than doubled between March and May  (Figure  3-10), i n a pattern s i m i l a r to that observed i n t i s s u e of shrubs, which were important d i e t a r y  components at t h i s  time  (Figure 3-4).  Forbs,  p r i m a r i l y Epilobium angustifolium, became a v a i l a b l e to deer during t h i s p e r i o d , received heavy use (Figure 3-4) and probably were the major f a c t o r b r i n g i n g about the increase i n crude p r o t e i n l e v e l s i n rumen contents. Since l e v e l s of crude p r o t e i n i n rumen content i n d i c a t e both forage and m i c r o b i a l p r o t e i n , i t i s l i k e l y that populations of microbes, which i n crease with improved forage ( K l e i n 1962), also contributed to the increase i n crude p r o t e i n observed. K i r k p a t r i c k et a l . (1969) documented a s i m i l a r seasonal pattern i n crude p r o t e i n content of w h i t e - t a i l e d deer rumens i n the  southeastern United  States.  Gasaway  and  Coady  (1974)  measured  seasonal crude p r o t e i n l e v e l s i n washed rumen contents of moose and observed s i m i l a r patterns of seasonal change, but lower o v e r a l l l e v e l s since washing removes amino a c i d s , soluble forage p r o t e i n , and m i c r o b i a l p r o t e i n ( K l e i n 1962).  179  Klein  (1962) determined  that washed rumen samples consisting only Of  forage material, and assumed to represent composition of forage ingested, contained about 60 percent of the crude protein contained in unwashed samples of rumen contents of black-tailed deer.  Applying this value (60  percent) to the unwashed samples collected in the present study, crude protein contents of forage ingested during the fall-winter period were 8.2 and 11.1 percent in forested and cutover areas, respectively. These values are slightly higher than those of the fall-winter "diet" in Table 3-13 which were calculated based on the major forage species observed in rumen analyses for food habits.  However, not a l l minor species eaten  were considered in the "diet" and these may have influenced protein content.  Since protein requirement of forages for maintenance is 7 percent,  the application of Klein's relationship to crude protein observed suggests that fall-winter forages contained protein at greater than maintenance levels.  Additional work would be necessary to better define this rela-  tionship .  Statistically significant (p < 0.05)  differences occurred between levels  of crude protein in rumen contents of deer from forested and cutover areas in  spring, fall-winter and annually (Table 3-21).  areas were not sampled in summer.  Deer from forested  In a l l cases crude protein contents  were higher in deer from cutovers, probably as a result of the greater proportion of forbs in their diet.  Also, lichens, primarily Alectoria  sarmentosa, with a protein content of less than 2 percent (Figure 3-8) were important items in the fall-winter diet of deer from forested areas (Figure 3-1) and their presence probably depressed crude protein levels of rumen contents in these rumens.  180  SUMMARY - RUMEN CHARACTERISTICS  Patterns of variation observed  i n rumen dry matter and crude protein  content and rumen f i l l reflected the seasonal and monthly changes which occurred i n food habits and i n nutrient levels i n forage plants. The degree of change occurring in rumen f i l l and dry matter content was relatively minor compared to changes i n crude protein content, which reflected higher protein levels in forage and probably also the response of microbial populations to this increase.  Levels of dry matter and rumen f i l l were consistently higher and crude protein content was consistently lower in forested areas compared to cutovers as a result of differences i n diet of deer from the two areas. Except for seasonal differences in crude protein content, statistically significant differences were few due to the small magnitude of change and the relatively small sample sizes in some seasons.  Levels and magnitude of change i n rumen characteristics were generally consistent with those reported for other Cervidae, with some exceptions related to major dietary shifts, e.g. white-tailed deer use of acorns in fall.  SUMMARY - CHAPTER III  Treating the related  areas of food habits, characteristics of forage  plants and rumen characteristics together i n this chapter resulted i n an extensive amount of information, with numerous levels of stratification.  181  The intent of this section is to summarize some of the key findings of this portion of the study.  Food Habits  1)  Deer were opportunistic became available.  feeders, utilizing  forages as they  Fungi and berries of Rubus and Vaccinium  spp. are forages which received heavy use during their short periods of availability in f a l l and late summer, respectively.  2)  Feeding patterns were closely tied to phenology of plants; major dietary shifts occurred i n spring as new plant tissue became available and i n f a l l as frost reduced availability of some species.  3)  Forbs and shrubs were of equal importance in the annual diet; perennial forbs were used during a l l periods in which they were not covered by snow.  4)  Conifers and lichens were important winter foods.  Conifers  were high i n availability relative to other forage types in winter.  Lichens  became  available  via l i t t e r f a l l  and were  apparently a preferred forage since they were not widely available.  5)  Shrubs, conifers and lichens made up substantially more of the diet of deer from forested than cutover areas. Forbs were the largest dietary seasons.  component in deer from cutover areas in a l l  182  6)  Reduced availability of forage in fall-winter was reflected in the reduced number of species present in rumens of deer collected in this period.  7)  The observation that forbs are of high importance is consistent with  the  findings  Vancouver Island.  of  Gates  (1968) who  worked  i n central  Cowan (1945) and Brown (1961) noted that  deer were primarily browsers, making l i t t l e use of low-growing vegetation on a year-round basis in southern Vancouver Island and western Washington, respectively.  Forage Characteristics  1)  Distinct seasonal patterns related to phenological stage of the plant were observed  in levels of various characteristics of  most species.  2)  Maturation of plants was reflected in an increase in dry matter content and fibre and lignin levels, with a corresponding decrease in cell contents, crude protein and dry matter digestib i l i t y in most species.  3)  Ferns and lichens presented exceptions to the pattern of decreased nutritional value as maturation proceeded; lichens were highly digestible during the dormant period probably because of their high hemicellulose and low lignin content.  Ferns con-  tained high levels of lignin, and were low in digestibility in spring.  183  Conifers  displayed less variation  in levels  of most forage  components during the year than other forage types.  Lichens  and  conifers  contained  less  than the minimum crude  protein requirement of 7 percent for maintenance during most of the year, ferns and forbs contained greater than 7 percent a l l year and shrubs were slightly below this level in fall-winter.  Consistent patterns of increased levels of forage components in a species collected observed;  probably  i n forested and  cutover areas were not  because of microclimatic variability and  resulting phenological differences between these areas.  Digestibility of forage species in vitro was generally enhanced when they were part of forage mixtures; apparently since rumen microbial growth and fermentation components were improved with a variety of substrates.  Digestibilities  of forage mixtures  levels as proportion of Alectoria  increased beyond expected sarmentosa in the diet in-  creased indicating an enhancement effect associated with this highly digestible species.  Rates of digestibility were assessed; most species were fully digested  in 24 hours indicating  they would be nearly fully  utilized i f rumen turnover times are 14 to 33 hours as reported in the literature.  184  Rumen Characteristics  1)  Crude protein and dry matter levels of rumen contents showed patterns of variation parallel to those which occurred in forage plants, and reflected seasonal changes in food habits.  2)  Rumen f i l l varied seasonally, with lowest levels in spring when forage quality and rumen turnover rates are normally high and highest levels in fall-winter when forages are fibrous and least digestible.  3)  Differences in rumen characteristics in deer from forested and cutover areas appeared to be the result of different food habits in these areas of collection.  4)  Levels  and patterns  observed  were  of variation  consistent with  i n rumen  literature  characteristics  values  for other  Cervidae.  Distinct seasonal patterns in nutrient-fibre composition in major forage species were documented and additional analyses made which provide an assessment of their nutritional value to black-tailed deer.  Patterns of  forage utilization can generally be explained on the basis of nutritional value, as modified by seasonal availability of forage plants.  Given a  choice, deer selected individual species at the time they were most nutritious and selected the most nutritious plants, of those examined in this study, among those available at a particular period.  185  Analyses of rumen characteristics provided insight into the qualitative nature of the diet selected and reflected the changes observed in composition of forage plants.  186  LITERATURE CITED Ammann, A.P., R.L. Cowan, C L . Mothershead and B.R. Baumgardt. 1973. Dry matter and energy intake in relation to digestibility in white-tailed deer. J. Wildl. Manage. 37:195-201. Anthony, R.G. and N.S. Smith. 1974. 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Nutritional requirements and growth of black-tailed deer Odocoileus hemionus columbianus in captivity. Symp. Zool. Soc. Lond. 21:89-96. Nowlin, R.A. 1974. Prescribed burning effects on i n vitro digestibility of elk browse. M. Sc. Thesis. Univ. of Idaho, Moscow, ID. 27 pp. Oh, H.K., B.R. Baumgardt, and J. M. Scholl. 1966. Evaluation of forages in the laboratory. V. comparison of chemical analysis, solubility tests and in vitro fermentation. J. Dairy Sci. 49:850-855. Palmer, W.L., R.L. Cowan and A.P. Ammann. 1976. source on in vitro digestion of deer foods.  Effect of inoculum J. Wildl. Manage. 40:301-307.  Pearson, H.A. 1969. Rumen microbial ecology in mule deer. Microbiol. 17:819-824.  Appl.  Pearson, H.A. 1970. Digestibility t r i a l s : in vitro techniques, pp. 8592 i n Range and wildlife habitat evaluation - a research symposium. U.S.D.A. Misc. Publ. 1147. Person, S.J., R.'G. White and J.R. Luick. 1975. In vitro digestibility of forages utilized by Rangifer tarandus. First International Reindeer/caribou symposium. Fairbanks, Alaska, pp. 251-256. Pew, J.C, and P. Weyna. 1962. Fine grinding, enzyme digestion, and the lignin-cellulose bond in wood. TAPPI 45:247-256. Prins, R.A. and M.J. H. Geelen. fallow deer, and roe deer.  1971. Rumen characteristics of red deer, J. Wildl. Manage. 35:673-680.  Robbins, C.J., P.J. Van Soest, W.W. Mautz, and A.N. Moen. 1975. Feed analyses and digestion with reference to white-tailed deer. J. Wildl. Manage. 39:67-79. Ruggiero, L.F. and J.B. Whelan. 1976. A comparison of i n vitro and i n vivo digestibility by white-tailed deer. J. Range Manage. 29:82-83. Russel, R.N., and J.A. Turner. 1975. Foliar moisture trends during bud swelling and needle flush in British Columbia. B.C. Forest Service. Bi-monthly Research Notes. 31:24-25. Schwartz, C.C. and J.G. Nagy. 1972. Maintaining deer rumen fluid for in vitro digestion studies. J. Wildl. Manage. 36:1341-1343. Scotter, J.W. 1965. Chemical composition of forage lichens from nothern Saskatchewan as related to use by barren-ground caribou. Can. J. Plant Sci. 45:246-250. Scotter, J.W. 1972. Chemical composition of forage plants from the Reindeer Reserve, Northwest Territories. Arctic 25:21-27. Short, H.L. 1963. Rumen fermentations and energy relationships in whitetailed deer. J. Wildl. Manage. 27:184-195.  190  Short, H.L. 1969. Physiology and nutrition of deer in southern upland forests, pp. 14-18 In: White-tailed deer i n the southern forest habitat. L.K. Halls~Xed.) Symp. Proc. Nacogdoches, Texas. USDA Forest Service Southern Forest Expt. Sta. 130 pp. Short, H.L. 1971. Forage digestibility and diet of deer on southern upland range. J. Wildl. Manage. 35(4):698-706. Short, H.L. 1975. Nutrition of southern deer in different seasons. J. Wildl. Manage. 39:321-330. Short, H.L., R.M. Blair, and L. Burkart. 1972. Factors affecting nutritive values, pp. 311-318 In: Wildland shrubs: Their biology and utilization. U.S.D.A. Forest Service General Technical Rept. INT-1 494 pp. Short, H.L., R.M. Blair and E. A. Epps, Jr. 1973. Estimated digestibility of some southern browse tissues. J. Anim. Sci. 36:792-796. Short, H.L., R.M. Blair, and E.A. Epps, Jr. 1975. Composition and digestibility of deer browse i n southern forests. U.S.D.A. Forest Service Res. Paper. S0-111. 10 pp. Short, H.L., R.M. Blair, and CA. Segelquist. 1974. Fiber composition and forage digestibility by small ruminants. J. Wildl. Manage. 38:197-209. Short, H.L., D.R. Dietz, and R.E. Remmenga. 1966. mule deer browse plants. Ecology 47:222-229.  Selected nutrients in  Short, H.L., D.E. Medin, and A.E. Anderson. 1965. Rumino-reticular characteristics of mule deer. J. Mammal. 46:196-199. Short, H.L., and J.C. Reagor. 1970. Cell wall digestibility affects forage value of woody twigs. J. Wildl. Manage. 34:964-967. Short, H.L., E.E. Remmenga, and C E . Boyd. 1969. Variations in ruminoreticular contents of white-tailed deer. J. Wildl. Manage. 33:187-191. Skeen, J.E. 1974. The relationship of certain rumino-reticular and blood variables to the nutritional status of white-tailed deer. Ph.D. Thesis. Virginia polytechnic Institute and State University. Blacksburg, Va. 98 pp. Sullivan, J.T. 1962. Evaluation of forage crops by chemical analysis: A critique. Agron. J. 54:511-515. Swift, R.W. 1948. Deer select most nutritious forages. Manage. 12:109-110.  J. Wildl.  Tilley, J.M.A. and R.A. Terry. 1963. A two-stage technique for the in vitro digestion of forage crops. J. British Grassland Soc. 18(277104-111.  191  Torgerson, 0., and W.H. Pfander. 1971- Cellulose digestibility and chemical composition of Missouri deer foods. J. Wildl. Manage. 35:221-231. Ullrey, D.E., W.G. Youatt, H.E. Johnson, A.B. Cowan, R.L. Covent, and W.T. Magee. 1972. Digestibility and estimated metabolizability of aspen browse for white-tailed deer. J. Wildl. Manage. 36:885-891. Ullrey, D.E., W.G. Youatt, H.E. Johnson, L.D. Fay and B.L. Bradley. 1967. Protein requirement of white-tailed deer fawns. J. Wildl. Manage 31:679-685. Ullrey, D.E., W.G. Youatt, H.E. Johnson, L.O. Fay, B.E. Brent, and K.E. Kemp. 1968. Digestibility of cedar and balsam f i r browse for white-tailed deer. J. Wildl. Manage. 32:162-171. Uresk, D.W., D.R. Dietz, and H.F. Messer. 1975. Constituents of in vitro solution contribute differently to dry matter digestibility of deer food species. J. Range Manage . 28:419-421. Urness, P.J. and C.Y. McCullough. 1973. Nutritional value of seasonal deer diets. Part III of: Deer nutrition in Arizona chaparral and desert habitats. Special Rept. No. 3. Ariz. Game and Fish Dept. and U.S. Forest Service, Rocky Mtn. For. and Range Exp. Station. 68 pp. Urness, P.J. D.J. Neff, and J.R. Vahle. 1975. Nutrient content of mule deer diets from ponderosa pine range. J. Wildl. Manage. 39:670-673. Van Dyne, G.M. 1962. Micro-methods for nutritive evaluation of range forages. J. Range Manage. 15:303-314. Van Soest, P.J. 1963. Use of detergents in the analysis of fibrous feeds. II. A rapid method for the determination of fiber and lignin. J. Assoc. Office Agr. Chem. 46:829-835. Van Soest, P.J. 1967. Development of a comprehensive system of feed analyses and i t s application to forages. J. Anim. Sci. 26:119-128. Van Soest, P.J., and R.H. Wine. 1967. Use of detergents in the analysis of fibrous feeds. IV. Determination of plant cell-wall constituents. J. Assoc. Offic. Agr. Chem. 50:50-55. Waldern, D.E. 1971. A rapid micro-digestion procedure for neutral and acid detergent fibre. Can. J. Anim. Sci. 51:67-69. Wallmo, O.C., L.H. Carpenter, W.L. Regelin, R.B. G i l l and D.L. Baker. 1977. Evaluation of deer habitat on a nutritional basis. J. Range Manage. 30:122-127. Weir, W.C. and D.T. Torrell. 1959. Selective grazing by sheep as shown by a comparison of range and pasture forage obtained by hand-clipping and that collected by esophageal-fistulated sheep. J. Anim. Sci. 18:641-649.  192  Weston, R.H. and J.P. Hogan. 1968. Factors limiting the intake of feed by sheep. IV. The intake and digestion of mature rye grass. Aust. J. Agric. Res. 19:567-576. Whelan, J.B., R.F. Harlow and H.S. Crawford. 1971. Selectivity, quality, and in vitro digestibility of deer foods: A tentative model. Trans. N.E. Fish and Wildl. Conf. 28:67-81. Wood, A.J., Kitts, W.D., Cowan, I. McT. 1960. The interpretation of the protein level in the nominal contents of deer. Calif. Fish and Game 46:227-9.  193  CHAPTER IV -  SEASONAL VARIATION IN ENERGY VALUES AND THEIR RELATIONSHIP TO OTHER CHARACTERISTICS OF FORAGE PLANTS OF BLACK-TAILED DEER  ABSTRACT  Energy content is a major determinant of the value of forage plants. In vitro  techniques permit the measurement of volatile fatty acids (VFA)  produced  in ruminal fermentation and the caloric content of these pro-  ducts can be analytically determined.  Using these techniques, the rela-  tive energy values of plants were examined as they varied seasonally and in  relation to other nutrient  black-tailed  deer.  characteristics and their selection by  Levels of VFA i n rumen contents and their caloric  value were determined to provide an estimate of total ruminal energy as it  varied  seasonally.  Forbs, represented by Epilobium angustifolium,  displayed the highest net energy content of the forages examined; shrubs and conifers were Intermediate and ferns and lichens had the lowest energy content.  Highest  seasonal energy  summer and slightly matter digestibility.  values in most forages occurred in  followed maximum levels of crude protein and dry Relationships of energy content to other nutrient  characteristics were variable and somewhat inconsistent.  Deer appeared  to select for plants high in energy and other nutrients in spring and summer; availability appeared to have a stronger influence on selection in fall-winter.  Energy content of deer rumen ingesta varied in the same  seasonal patterns as forage plants and was influenced both by rumen f i l l and VFA concentration.  194  CHAPTER IV - SEASONAL VARIATION IN ENERGY VALUES AND THEIR RELATIONSHIP TO OTHER CHARACTERISTICS OF FORAGE PLANTS OF BLACK-TAILED DEER  RATIONALE AND OBJECTIVES  The  nutritive values of forage plants depend i n part on the degree to  which they are converted into a chemical form usable as an energy source by the animal. carbohydrates  In deer and other ruminants, microbial fermentation of  in the rumen results  i n the formation of volatile  acids (VFA) which are metabolized to yield energy. produced  Quantification of VFA  during in vitro fermentation by microorganisms  should provide a relative measure of the energy  fatty  from deer rumens  values of individual  forage species as related to phenological stage or season of the year. The energy values of plants relative to their selection by deer can be examined to ascertain i f deer select for energy-rich foods.  Rates of VFA production can be determined per unit of rumen content and these values applied to total rumen digesta to estimate energy production in the intact animal on a seasonal basis and relative to forage consumed.  The objectives of energy measurements made in this study were:  1)  To determine  seasonal patterns of availability  major forage species.  of energy i n  195  2)  To determine i f a relationship exists between energy values of forage species and their selection by deer.  3)  To determine i f energy values differ within a forage species collected in cutover compared to forested areas.  4)  To  determine levels of energy production in rumens of black-  tailed deer relative to season and patterns of food selection as indicated by rumen content analyses.  LITERATURE REVIEW  VOLATILE FATTY ACIDS AND ENERGY PRODUCTION  Volatile  fatty acids (VFA)  are the primary  end products  of microbial  fermentation of carbohydrates and are the major energy source of ruminants (Hungate 1966).  Estimates of the proportion of total energy requirement  supplied by VFA range from 40 to 75 percent (Blaxter 1961). Short (1963) estimated that VFA supplied 50 percent of the maintenance energy requirement of white-tailed deer.  A number of VFA's are formed in carbohydrate fermentation and differ with regard to length of carbon chain or the isomeric configuration of the molecule. oxidation,  Individual VFA's yield different caloric values upon metabolic depending  on  their  molecular  structure.  These values are  constant for an individual acid and can be calculated for a VFA to provide a measure of i t s energy value.  mixture  The nutritionally-important  VFA's ranked in ascending order of caloric content are acetic, propionic, butyric, isobutyric, valeric and isovaleric acids.  Isobutyric and iso-  196  valeric  acids are formed from the fermentation of certain amino acids  (Hungate  1966).  They constitute a minor percentage of total VFA  quantities present provide  but  an indication of the relative magnitude of  protein fermentation.  A number of investigators have used VFA concentration in rumen fluid as an indicator of VFA production (Bruggemann 1968, Short et a l . 1969, Ullrey et  a_l.  1970,  Prins and Geelen 1971).  Weston and Hogan (1968) described  the correlation between VFA concentration and VFA production in domestic sheep.  Since the variation in this relationship can be high, Gasaway and  Coady (1974) recommend VFA  concentration be used only as an approximate  indicator of fermentation rates rather than an estimator of actual VFA production.  Rates of VFA production vary with changes in the quality of the diet.  In  moose, Alces alces, Gasaway and Coady (1974) measured rates of VFA production in winter about one-third as high as those in summer and attributed this  decrease  to reduced  browse quality.  Hogan et al (1969) observed  that as forage matured, VFA production in sheep decreased.  Rates of gas  evolution, another indication of fermentability, were observed to increase with increases in diet quality of white-tailed deer (Short 1963, Short et al.  1969).  Increased  levels of rumen f i l l  during winter periods when  forage quality is reduced partially compensate for reduced rates of fermentation in moose (Gasaway and summer Short  (1975) observed  Coady 1974).  In white-tailed deer in  a positive relationship between rumen f i l l  and total energy content of ruminal VFA's as calculated using total VFA concentration, percent composition and caloric values of individual fatty  197  acids.  In this  case, mushrooms  and acorns, with high caloric values,  were a major part of the diet.  Composition  of VFA in rumen digesta also is influenced by quality of the  diet (Short et a l . 1966).  Diets containing readily-digestible nutrients  result i n increased levels of propionic, butyric or higher acids and lower levels of acetic acid than low quality diets (Short 1963, Ullrey et a l . 1972).  Under these conditions energy production i s increased as propionic  acid contains about 40 percent more calories than acetic acid.  Rates of  food consumption affect the levels of energy available from VFA production in the rumen.  In response to increased levels of dry matter in diets  containing acorns, food consumption rates of white-tailed deer decreased (Short 1975).  The effect of the increase in dry matter and decrease in  consumption rates was a reduction in total caloric value of rumen VFA's even though this diet favored production of propionic and butyric acids which are high in caloric value.  The seasonal patterns of VFA production and their metabolic significance were examined for white-tailed deer by Short (1975).  Comparisons of VFA  production were made for black-tailed deer and sheep in pens or collected on the range by Alio et a l . (1973).  In the latter study, the zero-time  rate of fermentation was determined and provided an indication of rates of VFA production i n vivo for animals  subject to pen and range feeding  conditions and diets.  VFA production in the rumen and from fermentation of forage plants was measured in this study to provide information on production of ruminal energy and energy values of individual forage species.  198  METHODS  VOLATILE FATTY ACID (VFA) PRODUCTION  VFA production after 24 hours of fermentation was determined for a l l plant samples  collected.  Samples of 0.8  gram were incubated at 39°C under  anaerobic conditions in 25 mis of buffer solution and 10 mis of fresh rumen inoculum.  After 24 hours, microbial action was stopped through the  addition of concentrated KOH in tablet form. mentation fluid  was  A 20-ml sample of the fer-  decanted into a v i a l , which was  sealed and frozen  pending laboratory analysis of VFA production. A sample consisting only of rumen inoculum and buffer solution was included to indicate VFA contribution of the inoculum.  VOLATILE FATTY ACID DETERMINATION  The procedures described by Alio et a l . (1973) were employed with minor changes.  Quantitative  analyses to determine total  conducted on wet digesta samples.  amounts of VFA  present were  Samples were thawed, mixed thoroughly  and a 5-gram aliquot was acidified to pH 6.4 with concentrated sulfuric acid.  This aliquot was  steam distilled at 99.5°C for 20 minutes.  Dis-  t i l l a t e was collected in an ice bath and titrated with 0.01 N NaOH. Concentration of VFA was indicated by a pH change associated with the endpoint of titration.  VFA concentrations were expressed in milliequivalents  (meq) per 100 grams of wet digesta.  199  Qualitative analyses were made to determine the proportion of individual acids in the total VFA.  Thawed digesta samples were squeezed through  cheesecloth and acidified to pH 6.5 with metaphosphoric acid. sample was  centrifuged at 20,000 G for 15 minutes.  The liquid  Supernatant was  de-  canted and analyzed in an Aerograph model 204 gas chromatograph using a flame ionization detector and He as the carrier gas. was  equipped with a 180 x 0.3  percent SP-1200 and 1 percent  Proportions  The chromatograph  cm stainless steel column packed with 10  H3PO4  coated on 80/100 chromosorb  W-AW.  of individual acids were calculated from the relative peak  heights for each acid as charted on chromatograms.  Quantitative and qualitative analyses of VFA produced following fermentation of individual forage plants were conducted following the method of Alio et a l . (1973).  This method employs a mixed VFA standard of known  concentration and proportions of individual acids.  Concentration values  for unknown samples are calculated based on comparison of their peak heights with those of the standard. the sum  Total concentration is calculated as  of the concentrations of the individual acids.  for individual  forage species was  Net production  determined as the difference between  the species and a blank sample which contained only rumen inoculum  and  buffer solution.  ZERO-TIME FERMENTATION RATE  To obtain an estimate of VFA production and ultimately the energy value of this production in the intact animal, zero-time  fermentation  trials  200  were conducted. digestibility  Rumens of the 24 animals  and VFA production trials  collected  were used.  for the in vitro After  total rumen  weight was determined and inoculum samples taken, the entire rumen and its remaining contents were placed in a polyethylene bag and submerged in a water bath maintained at a constant 39°C.  A 100-ml sample of rumen  digesta was taken at the time the rumen was f i r s t opened, at 15-minute intervals  for the next hour and at 30-minute intervals for the next 3  hours.  Air was excluded by compressing the bag after each sample was  taken.  The bag was tied shut between samplings.  Samples were placed in  150-ml glass jars and microbial activity was stopped by the addition of six drops of concentrated KOH solution.  Samples were kept frozen until  lab analyses for VFA were made.  CALCULATION OF ENERGY VALUES OF VFA PRODUCED  Caloric  values of individual  volatile fatty  acids vary considerably.  Weast (1968) reported these values i n kilocalories per mole of acid as follows:  acetic (Cg) - 209 propionic (C3) - 367 butyric (C ) - 524 4  isobutyric ( C 4 ) - 524 valeric (C ) - 628 5  isovaleric (C5) - 628  Total quantities of VFA and percentage of individual VFA's produced i n fermentation of individual forage plants or rumen contents were determined as described above. Percentage composition of individual VFA's multiplied by total VFA production yield the net production of each VFA. Multipli-  201  cation of this value by the caloric value of each VTA provides the net energy produced in calories of individual VFA's.  These values can then  be added together to indicate total energy value of VFA's produced.  In  the case of zero-time fermentation rate studies, net VFA production per unit of inoculum per unit of time can be determined and related to metabolic needs of the animal on a 24-hour basis (Alio et a l . 1973).  This  calculation is made by multiplying net VFA production per unit inoculum by the total inoculum in the rumen at time of collection.  Weight of rumen tissue was determined at the completion of the fermentation rate t r i a l . weighing.  The tissue was washed and excess water removed prior to  Total rumen weight at time of collection less weight of rumen  tissue provided a measure of rumen content weight.  RESULTS AND DISCUSSION  In the following discussion, VFA production and caloric values of fermentation products of forage plants are treated within the five forage types as well as individual species.  Seasonal designations are the same  as those discussed in Chapter III: spring (May and June), summer (July through  September),  and  fall/winter  (October  through April).  Values  presented in the text are x (± SE-).  VFA PRODUCTION AND ENERGY VALUES OF FORAGE PLANTS  Average annual levels of VFA production and associated caloric values from in vitro fermentation of forage types are presented in Table 4-1.  202  On an annual basis, the forb (Epilobium angustifolium) which was available only from April through October produced highest levels of VFA with greatest  caloric value  (3.7 ± 0.3 kcal/0.8 g dry matter).  Shrubs and  conifers produced similar levels of VFA and had similar caloric values, as  did lichens and ferns.  There were few significant differences in  patterns of VFA production or caloric value associated with area of collection on an annual basis.  Comparisons of forage types with each other within seasons (Table 4-1) followed patterns similar to those observed  on an annual basis.  Forbs  were particularly high in caloric value (4.9 ± 0.4 kcal/0.8 g) in summer. Lichens and ferns were significantly lower in caloric value than shrubs and  conifers during spring and fall-winter but not during summer. A l l  types except shrubs displayed their highest caloric content during summer. Other investigators have observed that highest levels of VFA-energy occur in spring and summer.  Production of VFA from a given diet is not only a  function of the levels of soluble carbohydrates and protein in the forage (Weston and Hogan 1968), but also reflects the population levels of rumen microbes.  Greater  rates of VFA production  result  from higher  initial  populations of microbes (El Shazly and Hungate 1955 in Skeen 1974). The greater VFA production observed in summer compared to spring may reflect the fact that diets of the deer collected in spring contained mixtures of dormant as well as newly emerging vegetation. Thus, rumen microbial populations may have been lower than i n summer when the proportion of new foliage  i n the diet was greater as was VFA production, as observed in  moose by Gasaway and Coady (1974). These investigators found that caloric values  of the spring-summer diet were 2-3 times that required to meet  Table 4-1.  Seasonal and annual l e v e l s o f VFA production and a s s o c i a t e d c a l o r i c values f o r forage types c o l l e c t e d i n f o r e s t e d (F) and cutover (C) areas. Net VFA Produced (mg/100 ml)  N Season Forage Type  F  C  F+C  24  24  48  F+C  C  F+C  F  750.9 ( 84.5)  755.8 (144.1)  3.3 (0.8)  a  3.3 (0.4)  3.3 (0.6)  711.3 ( 58.4)  717.5 ( 53.9)  3.1 (0.2)  3.1 (0.2)  3.1 (0.2)  -  -  C  F  C a l o r i c Value (kcal/0.3 g)  Spring Shrubs  760.7 (187.7) a  8  2  22  22  44  Lichens  8  -  -  Forbs  -  8  -  Ferns  16  16  32  592.9 (139.5)  Shrubs  19  20  39  Conifers  16  16  32  Conifers  723.7 ( 49.7) a  a  -  -  477.9 ( 61.5) b  a  a  a  2.1 (0.2)  b  -  -  633.3 ( 97.6)  613.1 (120.2)  2.6 (0.6)  : (0.4)  2.7 (0.5)  798.7 (300.0)  697.8 (215.1) a  746.9 (261.5)  ah 3. (1..3)  3. 0 (0.• 9)  3..2 (1.• 1)  901.9° (288.2)  798.0'  (148.4)  849.9 (231.6)  3.,8 (!•.1)  3.,4 • (0..6) .  3..6 (0..9)  -  794.4 (142.9) a  b  b  3.3 (0.6)  3  C  b  2  7  -  Summer  Lichens  8  Forbs  -  Ferns  8  _  '  _  16  1  -  610.4 (189.6) b  -  1173.6 (231.4) b  704.5 ( 66.6) ab  4  a  2.,7  a  a  b  (0.• 8)  _  8  8  ab  3  t787.8 ( 46.0) a  -  746.2 ( 70.0)  4.,9 (1..0) b  ^ab 3. (0.'3)  T3.,5 (0..2) a  3..3 (0. 3)  Table 4-1.  Continued. C a l o r i c Value (kcal/0.8 g)  Net VFA Produced Season Forage Type  (mg/100 ml)  N  F  C  F+C  Shrubs  44  44  Conifers  36  Lichens  F  C  F+C  F  C  F+C  88  561.8° (278.2)  576.0 (308.6)  568.9 (292.2)  2.4° (1.2)  2.4° (1.3)  2.4 (1.3)  36  72  445.5 (115.9)  487.0° (136.6)  466.2 (127.5)  1.8 (0.5)  2.0° (0.6)  1.9 (0.5)  12  -  -  -  1.1° (0.7)  -  -  4  -  -  -  2.2  Fall-Winter  Forbs  b  a  262.0° (166.8)  -  537.4  -  (  ab  b  -  ab  ( " )  " )  20  20  40  316.7° ( 52.5)  348.8 (121.8)  332.8 ( 94.0)  1.4° (0.2)  1.5 (0.5)  1.4 (0.4)  Shrubs  87  88  175  668.4 (280.9)  651.4° (255.3)  659.8 (267.7)  2.9° (1.2)  2.8° (1.1)  2.8 (1.2)  Conifers  74  74  148  626.9 (244.6)  620.9°° (180.7)  623.9 (214.3)  2.7° (1.0)  2.6°° (0.8)  2.6 (0.9)  Lichens  28  -  -  423.3 (210.9)  -  20  -  44  88  Ferns  b  b  Annual  Forbs  Ferns  -"  44  a  a  b  -  894.7 (301.9)  • -  b  487.7 (187.6) b  532.1° (204.5)  1.8 (0.9) b  3.7 (1.3)  •-  2.3° (0.9)  2.2 (0.9)  b  ' -'  509.8 (196.4)  - '  -  2.1 (0.8) b  W a l u e s i n a column with a common s u p e r s c r i p t l e t t e r ( a , b, c) are not d i f f e r e n t a t p < 0.05 l e v e l as determined by a n a l y s i s o f v a r i a n c e and Scheffe's t e s t . Standard d e v i a t i o n . S i g n i f i c a n t d i f f e r e n c e between VFA o r c a l o r i c value i n f o r e s t e d or cutover i n d i c a t e d as t (p < 0.05) as determined by a n a l y s i s of v a r i a n c e ; S i g n i f i c a n c e i n d i c a t o r i s beside the greater v a l u e . 2  205  maintenance energy requirements.  During this period of excess dietary  energy the fat resources depleted during winter and through pregnancy and lactation were replenished. Short (1975) pointed out that i n white-tailed deer in late summer and early autumn, energy demands above maintenance requirements are comparatively few and that extensive fat deposition can occur i f proper energy sources are available.  Statistical comparisons of seasonal differences in net VFA production and caloric value in individual forage types are displayed in Table 4-2. In shrubs, caloric value levels were not different i n spring and summer, but were statistically lower than either of these periods during the f a l l winter period.  The maximum values are associated with the periods of  active growth in shrubs.  In conifers, VFA production and caloric values were statistically different in a l l seasons, with greatest values occurring i n summer (Table 4-2).  Since i t was d i f f i c u l t during spring to distinguish between tissue  produced during the current year and that of the previous year, but this distinction could be made in summer, the maximum summer values may be a reflection of this separation.  VFA  concentration and caloric values of lichens (Alectoria sarmentosa)  were statistically  lower  during fall-winter  than other seasons,  even  though digestibilities were generally greatest at this time (Figure 3-8). This decline during fall-winter was mainly a function of changes which occurred i n the plant i n early winter (October) as a standard sample collected earlier in the year and fermented at this time showed only a minor reduction in caloric value (Figure 4-3).  T a b l e 4-2.  S t a t i s t i c a l comparisons o f s e a s o n a l l e v e l s o f VFA p r o d u c t i o n and a s s o c i a t e d c a l o r i c v a l u e s f o r f o r a g e types c o l l e c t e d i n f o r e s t e d (F) and cutover (C) a r e a s .  Forage Type - Season  C a l o r i c Value ( k c a l / 0 . 8 g)  Net VFA produced (mg/100 ml)  N  F+C  F+C  F+C  Shrubs Spring  24  24  48  760,. 7 (187 • 7 )  750 . 9 ( 84.5)  755 .8 (144 • 1)  3.,3 (0. .8)  3 .3 (0 • 4)  746 .9 (261 • 5)  3,,4 (1. .3)  3 (0 • 9)  a  3 1  2  a  a  .o  ab  3..3 (0. 6) 3..2 (1. 1)  Summer  19  20  39  798 .7 (300 • 0)  697 . 8 (215 .1)  Fall-Winter  44  44  88  561 .8 (278 • 2)  576 (308 • 6)  568 .9 (292 • 2)  2,,4 (1. .2)  2 .4 (1 .3)  Annual  87  88  175  668 .4 (280 • 9)  651 .4 (255 • 3)  659 .8 (267 • 7)  2,.9 (1 • 2.)  2 .8 (1 • 1)  2,.8 (1. .2)  22  22  44  723. 7 ( 49.7)  711.,3 ( 58.4)  717 .5 ( 53• 9)  3. l (0. 2)  3. 1 (0. 2 )  3.1 (0.2)  849 .9 (231 • 6)  3.,8 (1. 1)  3. 4 (0. 6)  1.,8 .5)  2. (0. 6)  1.9 (0.5)  2..7  2. 6 (0. 8)  2.6 (0.9)  a  b  a b  .o  b  a  b  2..4 3)  b  •Cl.  Conifers Spring  a  3  ,o  b  ,o  c  a  Summer  16  16  32  901. 9 (288. 2)  798. (148..4)  Fall-Winter  36  36  72  445. 5 (115. 9)  487. (136,• 6)  466 .2 (127 • 5)  (o.  Annual  74  74  148  626. 9 (244. 6)  620,.9 (180 • 7)  623 .9 (214 • 3)  (1. .0)  b  C  b  C  a  o  b  3  3.6 (0.9)  Table  C a l o r i c Value (kcal/0.8 g)  Net VFA produced (mg/100 ml)  N  Forage Type - Season  4-2.  F+C  F+C  F+C  Lichens Spring  8  477.,9 ( 61. .5)  2.1 (0.2)  Summer  8  610.,4 (189. 6)  2.7 (0.8)  -  a  a  -  a  a  Fall-Winter  12  262.,o (166,• 8)  (0.7)  Annual  28  423,.3 (210 • 9)  1.8 (0.9)  l.l  b  -  b  -  Forbs Spring  8  Summer  8  Fall-Winter  4  Annual  20  -  794.4 (142.9)  3.3 (0.6)  _  1173.6 (231.4)  4.9 (1.0)  _  537.4 ( ")  2.2 ( -• )  894.7 (301.9)  3.7 (1.3)  a  b  C  a  b  C  T a b l e 4-2.  C a l o r i c Value (kcal/0.8 g)  Net VFA produced (mg/100 ml)  Forage Type - Season  F+C  F+C  F+C  Ferns 2.7 (0.4)  a  2.7 (0.5)  3.1 (0.3)  b  T3.5 (0.2)  3.3 (0.3)  332.8 ( 94.0)  1.4 (0.2)  1.5 (0.5)  509.8 (196.4)  2.1 (0.8)  2.3 (0.9)  16  16  32  592.9 (139.5)  633.3 ( 97.6)  613.1 (120.2)  2.6 (0.6)  8  8  16  704.5 ( 66.6)  3  t787.8 ( 46.0)  746.2 ( 70.0)  Fall-Winter  20  20  40  316.7° ( 52.5)  348.8 (121.8)  Annual  44  44  88  487.7 (187.6)  532.1 (204.5)  Spring  Summer  a  b  a  b  C  a  C  b  C  1.4 (0.4) 2.2 (0.9)  Values i n a column w i t h a common s u p e r s c r i p t l e t t e r ( a , b, c) a r e not d i f f e r e n t a t p < 0.05 l e v e l as determined by a n a l y s i s o f v a r i a n c e and S c h e f f e ' s t e s t . Standard deviation. Significant d i f f e r e n c e between VFA o r c a l o r i c v a l u e i n f o r e s t e d o r cutover i n d i c a t e d as t (p < 0.05) as determined by a n a l y s i s o f v a r i a n c e ; S i g n i f i c a n c e i n d i c a t o r i s b e s i d e t h e g r e a t e r v a l u e .  2  209  Caloric value and production of VFA from forbs were statistically different in each season and maximum in summer (Table 4-2). This pattern reflects the phenological changes occuring in the plant. In contrast to shrubs,  Epilobium  angustifolium probably  produces new tissue over a  greater proportion of the summer, and this may explain i t s higher caloric value in summer than spring.  Ferns also were significantly different in caloric value in a l l three seasons,  with maximum values occurring in summer.  Lignin content was  high during spring in ferns and may have influenced VFA production at that time.  The only instance in which statistically significant seasonal differences Occurred within forage types collected in forested and cutover areas was for ferns. During summer caloric value of ferns from cutovers was greater than from forested areas.  This difference is likely a function of the  relationships between fermentability and other nutrient characteristics which will be discussed later in this chapter.  Seasonal levels of VFA production for individual plant species are presented in Table 4-3. For the shrub species Gaultherja shallon, Vaccinium alaskaense and V. parvifolium, spring and summer caloric values were not statistically different.  This likely reflects the similar composition of  these species during these two periods.  Probably as a result of plant  maturation, significant differences occurred between fall-winter and the other two seasons for these species.  210  Table 4-3.  Seasonal and annual l e v e l s o f VFA p r o d u c t i o n and a s s o c i a t e d c a l o r i c v a l u e s f o r forage s p e c i e s c o l l e c t e d i n f o r e s t e d (F) and c u t o v e r (C) a r e a s .  Net VTA Produced (mg/100 ml)  N F  C  F  F+C  C  C a l o r i c Value (kcal/0.8 g)  ; "F+C  F  C  F+C  Shrubs  Gaultheria Spring  shallon 8  8  16  540.3 ( 39.9)  t 674.2 (26.0) 3  ai  2  a  607.3 ( 76.4)  2.3 (0.1)  +2.9 (0-2) a  2.6 (0.3)  a  a  a  Summer  8  8  16  632.7 (203.4)  599.3 (199.2)  616.0 (195.2)  2.6 (0.8)  2.5 (0.8)  2.6 (0.8)  FallWinter  12  12  24  384.0 (105.4)  389.6 (109.1)  386.8 (104.9)  1.6 (0.4)  1.6 (0.4)  1.6 (0.4)  Annual  28  28  56  499.7 (165.4)  530.9 (177.9)  515.3 (170.9)  2.1 (0.7)  2.2 (o.8) :  2.2 (0.7)  Vaccinium  alaskaense  a  b  a  b  a  b  a  b  a  b  3  b  Spring  8  8  16  +908.4 (163.6)  728.8 ( 62.2)  818.6 (151.3)  +3.9 (0-7) .  3.2 (0.2)  3.6 (0.6)  Summer  7  8  15  875.8 (390.1)  697.6 (230.0)  780.8 (316.3)  3.8 (1.7)  3.0 (1.0)  3.3 (1.4)  FallWinter  16  16  32  650.7 (322.5)  592.9 (302.6)  621.8 (309.0)  2.8 (1-4)  2.5 (1-3)  2.7 (1-3)  Annual  31  32  63  768.0 (322.5)  653.1 (246.9)  709.6 (290.1)  3.3 (1.4)  2.8  (l.D  3.1 (1.3)  833.3 ( 31.2) a  849.8 ( 22.5)  841.5 ( 27.6)  3.7 (0.1)  3.7 (0.1)  3.7 (0.1)  995.7  a  894.9 ( - )  945.3 ( 53.9)  4.3 ( - )  3.9 ( - )  4.1 (0.2)  Vaocinium  a  a  a  a  a  a  a  ab  b  a  a  a  a  a  3  a  at  b  parvifolium a  Spring  8  8  16  Summer  4  4  8  FallWinter  16  16  32  606.2 (271.8)  699.0 (358.5)  652.6 (316.5)  2.6 (1.2)  3.0 (1.6)  2.8 (1.4)  Annual  28  28  56  726.7 (252.9)  770.1 (280.6)  748.4 (265.6)  3.2 (1.1)  3.3 (1.2)  3.2 (1.2)  C  - ) b  a  a  a  a  a  b  a  a  b  a  a  a  a  b  211  Table 4-3. Continued.  Net VTA Produced (mg/100 mL)  N F  C  F+C  F  C  C a l o r i c Value ( k c a l / 0 . 8 g) F+C  F  C  F+C  Conifers  Pseudotsuga  menziesii  Spring  S  8  16  T758.7 ( 19.7)  713. l ( 44.9)  735.9 ( 41.0)  t3.3 (0.2)  3.1 (0.1)  3.2 (0.2)  Summer  4  4  8  958.6 ( - )  824.9 ( - )  891.7 ( 71.4).  4.0 ( - )  3.5 ( - )  3.7 (0.3)  FallWinter  12  12  24  465.7 ( 89.3)  t585.9 (136.0)  525.8 (128.2)  1.9 (0.4) C  T2.4 (0.6) b  2.2 (0.5)  Annual  24  24  48  645.5 (205.7)  668.1 (134.0)  656.8 (172.1)  2.7 (0.9)  2.8 (0.6)  2.8 (0.7)  Thuja  3  b  C  a  a  b  a  b  C  a  b  a  a  a  b  G  plicata  Spring  8  8  16  717.7 ( 35.9)  733.9 ( 73.9)  725.8 ( 56.7)  3.1 (0.1) a  3.2 (0,3)  3.2 (0.2)  Summer  8  8  16  677.l (173.5)  710.4 (159.4)  693.7 (161.9)  2.9 (0.7) a  3.1 (0.7)  3.0 (0.7)  FallWinter  12  12  24  415.8 (138.7)  431.l ( 71.1)  423.4 (108.1)  1.8 (0.6)  b  1.9 (0.4)  1.8 (0.5)  Annual  28  28  56  576.7 (190.7)  597.4 (177.9)  587.0 (183.0)  2.5 (0.8)  2.6 (0.8)  2.5 (0.8)  Tsuga  heterophylla  a  a  b  a  a  b  a  a  b  a  a  b  a  a  b  Spring  6  6  12  684.9 ( 64.6)  678.7 ( 42.0)  681.8 ( 52.1)  2.9 (0.2)  2.9 (o'.i)  a  2.9 (0.2)  Summer  4  4  8  1294.7 ( - )  946.5 ( - )  1120.6 (186.2)  5.3  3.9  b  ( ". )  ( ">  4.6 (0.7)  a  b  a  b  a  b  a  b  FallWinter  12  12  24 .  454.9 (118.4)  444.l (140.6)  449.5 (127.2)  1.9 (0.5)  1.8 (0,6)  1.9 (0.5)  Annual  22  22  44  670.3 (330.4)  599.4 (222.0)  634.9 (280.5) .  2.8 (1.3)  2.5 (0.9)  2.6 (1.1.)  C  c  C  C  C  212  Table 4-3.  Continued. C a l o r i c Value (kcal/0.8 R)  Net VFA Produced (mg/100 ml)  F+C  F+C  F+C  Lichens Alectoria  sarmentosa  Spring  8  477.9° ( 61.5)  2.1° (0.2)  Summer  8  610.4° (190.0)  2.7° (0.8)  FallWinter  12  267.0° (166.8)  l.l (0.7)  Annual  28  423.3 (210.9)  1.8 (0.9)  u  Forbs Epilobium  angustifolium  Spring  8  794.4° (142.9)  3.3° (0.6)  Summer  8  1173.6 (231.4)  4.9 (1.0)  FallWinter  4  537.4 ( - )  2.2 ( " )  Annual  20  894.7 (301.9)  3.7 (1.3)  b  C  b  C  213  Table 4-3.  Continued.  C a l o r i c Value (kcal/0.8 g)  Net VFA Produced (mg/100 ml)  F+C  F+C  F+C  Ferns  Blechnum  spicant + 3.0 (0.1)  2.6" (0.4)  Spring  8  8  16  510.6° ( 55.1)  +693.6 ( 28.2)  602.1" (103.4)  2.2° (0.2)  Summer  4  4  8  766.8 ( " )  830.8 ( " )  798.8" ( 34.2)  3.3" ( " )  3.6 ( " )  3.5" (0.2)  FallWinter  8  8  16  301.0 (69.7)  336.3 (107.6)  318.6 (89.5)  1.3 (0.3)  1.4 (0.5)  1.4 (0.4)  Annual  20  20  40  478.0 (184.7)  578.1 (219.6)  528.0 (206.6)  2.1 (0.8)  2.5 (1.0)  2.3 (0.9)  675.3 (152.2)  573.0" (106.5)  624.1" (137.4)  3.0° (0.6)  2.5" (0.5)  2.7" (0.6)  Polystichum  b  C  a  C  C  C  a  U  C  C  munition  Spring  8  8  16  Summer  4  4  8  642.3" ( " )  744.8" ( - )  693.5" ( 54.8)  2.8" ( - )  3.3" ( - )  3.0" (0.3)  FallWinter  12  12  24  327.3° (37.0)  357.2 (134.4)  342.2° (97.6)  1.4" (0.2)  1.5 (0.6)  1.5" (0.4)  Annual  24  24  48  495.8 (193.5)  493.7 (187.0)  494.7 (188.3)  2.2 (0.8)  2.2 (0.8)  2.2 (0.8)  a  C  4-  V a l u e s i n a column with a common s u p e r s c r i p t l e t t e r (a, b, c) are not d i f f e r e n t a t p < 0.05 l e v e l as determined by a n a l y s i s o f v a r i a n c e and Scheffe's t e s t . Standard deviation. ' S i g n i f i c a n t d i f f e r e n c e between VFA or c a l o r i c value i n f o r e s t e d o r cutover i n d i c a t e d as f (p < 0.05) as determined by a n a l y s i s of v a r i a n c e ; S i g n i f i c a n c e i n d i c a t o r i s beside the greater value.  2  214  In the conifer generally  Thuja  plicata,  not different  spring and summer caloric values were  but statistical  fall-winter and the other seasons  differences  occurred between  (Table 4-3). Maximum caloric values  were observed in summer for Pseudotsuga menziesii, and were statistically greater than spring values.  A possible explanation for the higher summer  values can be inferred from the work of Oh et a l . (1970).  These investi-  gators showed that simple sugar content increases during i n i t i a l stages of  maturation  declines levels  of shoots  as maturation  in P. menziesii.  proceeds,  of certain essential oils  increased structural  carbohydrate  apparently  Fermentability of tissue in response  to increased  inhibitory to rumen microbes, and to content.  The increase i n summer VFA  production over that in spring may reflect the effect of increased simple sugars.  Compared to very young growth, structural carbohydrate and essen-  t i a l o i l contents may not reach levels during the summer period sufficient to  affect  simple  the increased fermentability brought  sugars.  As indicated  about by increases in  in Table 4-3, VFA production and caloric  value were significantly lower in fall-winter than i n other seasons in P. menziesii.  Tsuga heterophylla displayed a pattern like P. menziesii, with highest caloric value i n summer, lowest spring  values  level  in fall-winter and intermediate  (Table 4-3). Caloric values and VFA production in the  forb, Epilobium angustifolium and lichen, Alectoria sarmentosa followed patterns similar to conifers and were treated earlier in the discussion of forage types. and  In the ferns from cutover areas, both Blechnum spicant  Polystichum munitum were significantly  different  in caloric value  between a l l seasons, with maximum values occurring in summer.  215  Significant effects on caloric value due to area of collection occurred infrequently within species (Table 4-3).  In spring G. shallon from cut-  overs was higher in caloric value than from forested areas, but this may have only reflected the delayed phenological development observed in the species growing in forested areas.  In V. alaskaense, plants collected in  forested areas produced fermentation fluid of higher caloric value than from cutovers. P. menziesii was also higher in caloric value in forested areas while B. spicant contained more energy in cutover areas.  There  were no obvious trends in one area compared to the other and the reason for the differences indicated above are not apparent.  The monthly patterns of variation in caloric values for individual species are graphically displayed in Figures 4-1 to 4-3.  For most species, energy  contents were related to stage of phenological development and followed closely the patterns observed for other characteristics such as crude protein or digestibility  of dry matter  (DDM).  Maximum caloric values  generally were associated with initiation of growth but may have slightly preceded  or followed actual bud burst.  The ferns followed the expected  pattern, i.e. highest energy at initiation and early development of new growth, even though DDM  was  lowest  at this  time.  This observation  probably reflects the unique chemical composition of ferns which was not elucidated by the analyses employed in this study.  Standard forage samples collected at one point in time and included in fermentation tests each month along with the current month's sample were employed with Gaultheria shallon and Alectoria sarmentosa. These standards were included under the assumption  that their chemical compositon  216  GAULTHERIA kcal/0.8 g 5  H  SHALLON kcal/0.8 g  5  FORESTED  t  CUTOVER  • — •  6  i  FORESTED  VACCINIUM  ALASKAENSE  CUTOVER  5 -•  5 •A -  4  3 -  3  2  2  1 1  1  VACCINIUM FORESTED  5  standard  T  PARVIFOLIUM  CUTOVER  4 3 2 -  2-  1-  1 i ~ l I I i ""I T-H | V""V ml J F M A M J J A S O H D 1  Figure 4 - 1 .  11  J F K A M J .  J A S ' O N D  Monthly patterns o f v a r i a t i o n i n c a l o r i c value o f fermentation products of s h r u b species. Values a r e means o f d u p l i c a t e samples f e r m e n t e d i n rumen f l u i d f r o m each o f two d e e r p e r m o n t h .  PSEUDOTSUGA MENZIESII  kcal/0.8 g 5  CUTOVER  FORESTED  .4 3.4 2 1  II 11  I  ' T V "I  THUJA PLICATA 1  5  FORESTED  CUTOVER  /A  4 3 2 1 1 I I  I  6' - | FORESTED  i  i  I  I  i  • , •,,!.•!•„•, i !  II  r  v  t  i  TSUGA HETEROPHYLLA  5-  4 -  :j  3 -  3-  CUTOVER  i A i i i i . i i J F M A M J J A S 0 !i D I  I  I  I  Figure 4 - 2 .  i I I J I I I I i J F M A M J J A S 1  Monthly patterns o f v a r i a t i o n i n c a l o r i c value o f fermentation products o f conifer species. Values are means of d u p l i c a t e samples fermented i n rumen f l u i d from each o f two deer per month.  i I I O N D  218  kcal/o.3 g 6 ^ kcal/0.8 g 5  ALECTORIA SARMENTOSA  FORESTED  4. 3  48-hr fermentati on * standard o — •  -  ::l 3  2- -  EPILOBIUM ANGUSTIFOLIUM  CUTOVER  -  2  1  1 1  II  n  BLECHNUM 5  SPICANT 5  -•  4  -  3  3  -  2  2  4  1  1  FORESTED  4-  CUTOVER  4  I I I I I I I I I 1I POLYSTICHUM 5 FORESTED  MUNITUM 5  4  4  3  3  2  4  1  i  CUTOVER  2 1  i I I iI I I I I i I I J F M A M J J A S O N D  I I I I I I I II J F M A M J J A S O N D  F i g u r e 4 - 3 . Monthly p a t t e r n s o f v a r i a t i o n i n c a l o r i c value o f fermentation products of l i c h e n , f o r b and f e r n s p e c i e s . Values a r e means o f d u p l i c a t e samples fernenteu i n rumen f l u i d from each o f two deer per month.  219  remained constant through time.  Their performance in fermentation evalu-  ations compared to the regular monthly sample helped explain whether monthly variation observed species  being  microbes.  was due to changes in composition  tested or in the fermentation  of the  capacity of the rumen  Patterns of variation in caloric value of fermentation products  of these standards are shown in Figure 4-1 and Figure 4-3 for G. shallon and A. sarmentosa, respectively. standard  sample closely paralleled  In G. shallon, caloric value of the that of the sample collected each  month, except in October, when fermentation products of the standard had greater energy value, indicating plant compositional changes were responsible for the lower values seen for the October sample. The same pattern occurred in A. sarmentosa, with reduced  caloric value of fermentation  products in October indicating compositional changes in the species. A decline in DDM at this time  (Figure 3-8) also occurred and suggests a  change had occurred in the plant.  In assessments of the rate of digestion of selected species, A. sarmentosa was observed  to be more slowly digestible  than other species tested  (Table 3-5). In light of relatively short rumen turnover times (14-33 hours) reported for white-tailed deer  (Mautz and Petrides 1971), and  probably also characteristic of black-tailed deer, i t appeared that A. sarmentosa might not be fully utilized before i t passed out of the rumen. To determine i f further breakdown of tissue, and greater caloric value would result additional products During  from longer fermentation, a sample was fermented for an  24 hours  (total  48 hours) each month.  of these 48-hour fermentations  Caloric value of  are displayed in Figure 4-3.  some months caloric values were 25-50 percent greater for the  220  extended fermentation than for the 24-hour period indicating that caloric value of A. sarmentosa may indeed not be fully realized by deer when rumen turnover times are less than 48 hours.  Annual and seasonal caloric values of individual forage species are compared  statistically  Vaccinium  in Table  spp. ranked  high  4-4.  Epilobium  in a l l seasons  angustifolium and the  while  A. sarmentosa and  Gaultheria shallon ranked consistently low i n caloric value.  Statistical  comparisons of these extremes indicated that differences were consistently significant.  Conifers displayed intermediate  caloric values.  Caloric  contents were highest during summer for a l l species, and generally were about twice as high as during fall-winter, the period of lowest caloric values.  COMPOSITION OF VFAs IN FORAGE SPECIES  Figures 4-4 to 4-6 graphically display seasonal composition of VFAs within species for forested and cutover areas.  As discussed earlier,  caloric  values of individual VFAs vary, thus both the amount and composition of total VFA produced in fermentation influence energy value of that production.  Generally, forages containing high amounts of readily fermentable nutrients produce lower levels of acetic acid and higher levels of propionic, butyric and higher acids than diets of lower nutrient composition (Short 1963, Short et a l . 1969, Ullrey et al. 1972). In poorly digested forages, not only i s production of acetic acid, with i t s low caloric content i n -  221  Table 4-4. S t a t i s t i c a l comparisons o f c a l o r i c v a l u e s (kcal/0.8 g d r y m a t t e r ) of f e r m e n t a t i o n products o f i n d i v i d u a l forage s p e c i e s . V a l u e s are seasonal and annual means f o r f o r e s t e d and c u t o v e r areas combined.  SPRING ' / / / / / / / / / / / / / / / / / / / / /  VAPA 3.7  VAAL 3.6  1  2  EPAN 3.3  PSME 3.2  THPL 3.2  TSHE 2.9  POMU 2.7  BLSP 2.6  VAPA 4.1  ///// PSME 3.7  \\\\ BLSP 3.5  VAAL 3.3  POMU 3.0  VAAL 2.7  EPAN 2.2  PSME 2.2  TSHE 1.9  THPL 1.8  GASH 1.6  VAPA 3.2  VAAL 3.1  TSHE 2.6  THPL 2.5  SUMMER / / / /  EPAN 4.9  TSHE 4.6  .  GASH .• 2.6  ALSA 2.1  THPL 3.0  ALSA 2.7  GASH 2.6  POMU 1.5  .BLSP 1.4  ALSA 1.1  FALL-WINTER VAPA 2.8  ANNUAL •//////  EPAN 3.8  1  Forage  SHRUBS  PSME 2.8  w w w w w w  BLSP 2.3  •.*.*.•  GASH 2.2  ALSA 1.8  s p e c i e s codes and type d e s i g n a t i o n s a r e a s f o l l o w s :  GASH = Gaultheria  shallon  CONIFERS ///,PSME = Pseudotsuga menziesii LICHEN ALSA = Alectoria sarmentosa  VAAL = Vaocinium alaskaense THPL = Thuja plicata  FORBS EPAN = Epilobium angustifolium FERNS s\\\BLSP = Blechnum spicant POMU = Polystichum 2  POMU 2.2  S p e c i e s n o t u n d e r l i n e d b y common l i n e a r e s t a t i s t i c a l l y by a n a l y s i s o f v a r i a n c e a n d S c h e f f e ' s t e s t .  VAPA = V. TSHE =  parvifolium  Tsuga .  heterophylla  munition different  (p < 0.05) a s d e t e r m i n e d  222  GAULTHERIA Percent Composition  SHALLON  kcal/0.8 g  (8)  (8)  Percent Composition  (12)  (8)  VACCINIUM  (8)  (12)  ALASKAENSE  5  100  80  4  80  4  60  3  60  3  40  »- 2  40  1-2  20  1  20  100 T|  •FORESTED  5  CUTOVER  1  1 -A-  -A -O  (8)  (7)  I  (16)  (8)  VACCINIUM FORESTED  (8)  (16)  PARVIFOLIUM CUTOVER  ,  -5  100  -4  80  60  -3  60  3  40 -J  -2  40  2  100 -| 80  4  20  20  -A—  T (8) Spring  -O-  (4)  Summer  -A  -A  -D  T (8) Spring  (16) FallWinter  T  (4)  Summer  -•  (16) FallWinter  'VFA are as follows: C = acetic acid, C = propionic acid, Cu = butyric and isobutyric acids, Other = valeric, isovaleric and higher acids, * = caloric value of VFA's produced in kcal/g. 2  3  2  Figure 4 - 4 .  Seasonal VFA composition and caloric values of fermentation products of shrub species. Values are means of duplicate samples; (n) = number of samples.  223  PSEUDOTSUGA Percent Composition  MENZIESII  kcal/o.8 g  Percent Composition  (8) THUJA 100 -•  FORESTED  80  PLICATA 100  5  (4)  r  CUTOVER  5  •- 4  80 -  4  60 -|  3  60 -  3  40  2  40 -  l  20 "  20  V  A-  -A A-  -A -D  D-  (8)  (8) r6  -I  60  TSUGA  20  h  (4)  (12)  Summer  Fall Winter  3-1  (8)  HETEROPHYLLA  100  - 5  CUTOVER  4  80  -4  3  60  -3  40  -2  20  -1  40  Spring  i  1-1  (12)  5  (6)  -  (12)  FORESTED  80  -A-  D— 1  (8)  2  *  i  I  I  (6)  (4)  (12)  Summer  FallWinter  Spring  'VFA are as follows: C = acetic acid, C = propionic acid, Ci, = butyric and isobutyric acids, Other = valeric, isovaleric and higher acids. * = caloric value of VFA's produced i n kcal/g. 2  3  2  Figure 4-5.  Seasonal VFA composition and caloric values of fermentation products of conifer species. Values are means of duplicate samples; (n) - number of samples.  224  Percent Composition 100  Percent k c a V 0.8 g CaTposition 100  ALECTORIA SARMENTOSA  5  l  80 60 \  Sk  40 -1 '  C  3  Cl*  A  -A *  _ -A—  A—  4  SO -  3  60 -  2  40 -  1  20 -  g  -A A-  a-  1_.Other a(8)  kcal/0.8 s-5  CUTOVER  FORESTED  S-  20  EPILOBIUM ANGUSTIFOLIUM  (8)  -A  (8) .  (12) BLECHNUM  (4)  SPICANT  100  FORESTED  (8)  CUT0VE.R  80 60 40 A  '  -A  —  20  A  D  •  (8)  (4)  —  -  •  ' (8)  POLYSTICHUM  100  (8)  (4)  (8)  Spring  Summer  Fal1 Winter  MUNITUM  FORESTED  80 60 40 20  Spring  Summer  Fal 1 yiDl§£  :  .  VFA a r e as f o l l o w s : C = acetic acid, C = propionic acid, Ci» = b u t y r i c and i s o b u t y r i c a c i d s , Other = v a l e r i c , i s o v a l e r i c and h i g h e r a c i d s . * = c a l o r i c v a l u e o f VFA's produced i n k c a l / g . 2  2  F i g u r e 4-6.  3  Seasonal VFA composition and c a l o r i c values o f f e r m e n t a t i o n products o f l i c h e n , f o r b and f e r n s p e c i e s . Values a r e means o f d u p l i c a t e samples; (n) = number o f samples.  225  creased, but rate of passage through the rumen and forage intake rates are decreased, further reducing the amount of net energy provided to the ruminant (Short 1975). Gasaway and Coady (1974) cited additional research verifying the increase in acetic acid relative to propionic acid with low quality forages.  They cautioned against attaching great significance to  acetic-propionic ratios as an indicator of forage composition and quality since exceptions occur (Weston and Hogan 1968), particularly i f sample sizes are small.  A fairly uniform pattern of change in seasonal VFA composition was noted for nearly a l l species (Figure 4-4, 4-5, 4-6).  Consistent with the find-  ings of others referenced above, acetic acid concentrations were lowest in spring, the time at which fermentable carbohydrates and protein contents are normally greatest. Unlike other work cited earlier, propionic acid concentrations were not highest during the spring and summer growing periods, but peaked during fall-winter.  Low levels of propionic acids  were offset by increased concentrations of butyric, isobutyric and higher acids, resulting in greatest energy values in spring and summer for most species.  These acids also tend to be present in greater concentrations  when forages high in readily fermentable carbohydrates are digested, and isobutyric and isovaleric acids arise directly from the fermentation of certain amino acids (Hungate 1966).  Concentrations of these branched-  chain acids provide a relative indication of the magnitude of protein fermentation  (Gasaway and Coady 1974), which probably  explains their  higher levels in spring and summer when protein contents of forages are greatest.  226  Statistical  comparisons of the seasonal levels of acetic and propionic  acid indicate significantly greater concentrations of both acids in f a l l winter  than  the other  seasons  for most species.  The concentrations  observed i n spring for butyric and higher acids were significantly greater than  summer concentrations which  significantly  exceeded  those  of the  fall-winter period for most species.  RELATIONSHIP OF VFA COMPOSITION AND ENERGY VALUE TO OTHER NUTRIENT CHARACTERISTICS OF FORAGE PLANTS  Correlations of caloric value and percentage  composition of acetic and  propionic acids with other nutrient characteristics of forage types are shown i n Table 4-5. those  for which  Variables selected for correlation analysis were  nutritional  significance  i s most well-defined. Only  correlations for shrubs, conifers and ferns are presented; no significant correlations occurred for forbs and lichens.  In general the number of significant correlations observed was relatively low.  This probably  comes about since VFA composition i n the rumen i s  influenced by a variety of factors, including sampling time (Skeen 1974), which was not well standardized in the collection of wild deer i n this study.  Bath and Rook (1963) in Skeen (1974) emphasized that significant  differences in VFA production may even occur between cattle on the same ration.  Variability associated with factors of this type, in conjunction  with a relatively low number of observations, probably contributed to the low number of significant correlations observed.  T a b l e 4-5.  C o r r e l a t i o n s o f c a l o r i c c o n t e n t , VFA and n u t r i e n t c h a r a c t e r i s t i c s o f f o r a g e t y p e s . O n l y s i g n i f i c a n t (p < 0.05) v a l u e s a r e l i s t e d . C o r r e l a t i o n s are f o r seasonal and a n n u a l measurements o f s a m p l e s f r o m f o r e s t e d and c u t o v e r a r e a s combined.  SHRUBS Correlation of: S p r i n g  (12)  5  Summer (14)  FallWinter ( 9)  CONIFERS Annual (35)  Spring (12)  Summer (10)  FallWinter ( 6)  FERNS Annual (28)  3  Annual (12)  C a l o r i c v a l u e o f VFA w i t h : percent acetic acid percent propionic acid crude p r o t e i n dry matter d i g e s t i b i l i t y acid-detergent lignin  Percent a c e t i c acid  61  0.87  0.90 -0.93  0.35  59  67  0.78  0.46 -0.58  -0.77  with:  percent propionic acid crude p r o t e i n dry matter d i g e s t i b i l i t y acid-detergent lignin  Percent propionic  -0.34  acid  -0.86  -0.96  -0.61  -0.79  -0.72  -0.82 -0.51 -0.67 0.37  -0.70 0.62  -0.98 0.73 -0.85  -0.92  -0.60  -0.77 0.45  -0.92 0.77  -0.45  with:  crude p r o t e i n dry matter d i g e s t i b i l i t y acid-detergent lignin  0.59 0.77  0.78  0.33 0.68 -0.36  0.68  -0.64 0.88 0.70  0.88  0.71 0.50  -0.79 0.72  *None o f t h e s e a s o n a l c o r r e l a t i o n s f o r f e r n s were s i g n i f i c a n t , o n l y a n n u a l v a l u e s a r e p r e s e n t e d . ''Number o f measurements.  ho  ho  228  Caloric value of VFA produced in. fermentation was significantly correlated with other variables but these relationships varied with forage type. In shrubs, but not other types, crude protein and caloric values were positively  correlated.  This may come about since fermentation of certain  amino acids produces isobutyric and isovaleric acids which are high in caloric value.  Dry matter digestibility (DDM) in spring was positively  correlated with caloric value in conifers and shrubs, an expected result since higher acids result  from  fermentation of the higher levels of  readily digestible carbohydrates present at this time.  The reasons for  the negative correlation observed between DDM and caloric value in conifers in summer are not apparent.  A  significant  propionic  negative  correlation  acid percentages  occurred between acetic acid and  in a l l types  for a l l seasons.  A similar  negative relationship between these acids was observed by Skeen (1974). Other investigators (Short 1963, Hungate 1966, Gasaway and Coady 1974) have reported the increase of one or the other of these acids at the expense of the other, but controlled by the amount of readily-fermentable carbohydrate in the feed.  Crude protein content was positively correlated with acetic acid percentage in ferns and conifers, but these measures were negatively correlated in shrubs, an inconsistency for which reasons are not apparent.  Two correlations provide additional confirmation of the observation frequently reported in the literature that digestion of readily-fermentable feeds result in greater quantities of propionic compared to acetic acid.  229  Table 4-5 indicates that DDM  and acetic acid percentages are negatively  correlated in shrubs and conifers, while percentages of propionic acid are positively correlated with DDM in ferns, conifers and shrubs.  Significant  correlations  of acid-detergent lignin with VFA  variables  occurred but did not follow a consistent pattern between forage types.  Correlation coefficients for caloric values, VFA and nutrient variables in individual forage species are presented in Table 4-6.  Because of the  limited number of samples, only the mean annual values, combined for cutover and  forested areas are reported.  Where significant correlations  between VFA and nutrient variables were observed for individual species, they generally followed the patterns observed for forage types.  In only  a few instances were significant correlations observed in three or more species. of VFA  These included a negative correlation between caloric value and  percent  propionic acid  in Gaultheria shallon,  Vaccinium  alaskaense, Thuja plicata and Tsuga heterophylla, The reasons for this relationship are not apparent. of these  forages results  It may reflect the fact that fermentation  in proportionately greater amounts of acids  higher than propionic, with greater caloric content.  As  in forage  types, percentages  of acetic  and propionic acids were  negatively correlated, with statistically significant values shown for Gaultheria shallon, Vaccinium parvifolium, Tsuga heterophylla and Blechnum spicant (Table 4-6).  This relationship comes about since fermentability  of forage causes one or the other acid to increase at the expense of the other.  Table 4-6.  Correlation  C o r r e l a t i o n s of c a l o r i c content, VFA and n u t r i e n t c h a r a c t e r i s t i c s of forage s p e c i e s . Only s i g n i f i c a n t (p < 0.05) values are l i s t e d . C o r r e l a t i o n s are f o r annual measurements of samples from f o r e s t e d and cutover areas combined. 1  of:  Gaultheria shallon (12)  C a l o r i c value of VFA  2  Vaccinium alaskaense (14)  Vaccinium parvifolium ( 9)  Pseudotsuga menziesii  Tlruja plicata  Tsuga heterophy I la  Blechnum spicant  ( 8)  (12)  (8)  (8)  Polystichum munitum (4)  with:  percent a c e t i c a c i d percent p r o p i o n i c a c i d -0.75 crude p r o t e i n .. dry matter d i g e s t i b i l i t y .. acid-detergent l i g n i n ..  -0.62 .. -0.54 ..  .. .. -0.79  .. .. ..  -0.72 ..  -0.89  Percent a c e t i c a c i d w i t h : percent p r o p i o n i c a c i d crude p r o t e i n dry matter d i g e s t i b i l i t y acid-detergent l i g n i n  -0.66 0.58  -0.77 -0.66  -0.74  -0.78 0.71  -0.94 0.72  0.98  0.75  Percent p r o p i o n i c a c i d w i t h : crude p r o t e i n -0.59 dry matter d i g e s t i b i l i t y .. acid-detergent l i g n i n ..  .. .. ..  'No s i g n i f i c a n t c o r r e l a t i o n s occurred f o r Alectoria Number of measurements.  ... .. ..  .. .. ..  sarmentosa or Epilobium  .. ..  .. ..  -0.82 -0.88  angustifolium.  2  o  231  RELATIONSHIPS OF VFA CHARACTERISTICS OF FORAGE PLANTS TO FOOD HABITS OF DEER  Because of the wide variety of plant species eaten compared to the relatively small number for which VFA assessments were made, i t is not possible to test statistically whether or not deer select for energy-rich foods.  Several trends are evident from the data which suggest at least a  coincidental relationship.  During spring, summer and on an annual basis shrubs and forbs had highest levels of caloric content  (Table 4-1)  (Figure 3-1).  shrubs were highest in caloric value and in  Similarly,  level of use in fall-winter.  as well as highest levels of use  During spring and summer, when availability  is high for a variety of plant species, deer appear to be selecting those plants which are most nutritious.  Thus along with high energy content,  they generally are high in crude protein, cell contents and dry matter digestiblity, a l l of which contribute to the high energy values observed. For this reason i t is probably not yalid to suggest that forage plants are being selected only for their value as a source of energy.  During  the fall-winter period, forage availability seems to play a more important role as suggested  by the relatively high use of lichens (Figure 3-1) at  this time, even though they are low in energy content. extremely  low in lichens but digestibility is high.  Crude protein is  Since direct nutri-  tional value of lichen appears low, one could speculate that i t s use may be connected with the apparent enhancement effect i t has on digestibility of a diet mixture (Table 3-12).  232  To summarize, these data circumstantially suggest that deer are selecting for forages of high nutritional value, of which energy content i s one component.  The food habits data are too variable to attempt to define a  direct relationship specifically between energy content and forage preference .  VFA CHARACTERISTICS OF DEER RUMEN CONTENTS  As discussed in the introductory section of this chapter, in vitro trials were run to estimate rates of VFA production in vivo at the time of deer collection.  Regression analysis was employed, following the approach of  Alio et a l . (1973), to define zero-hour production rates.  Because of the  large amount of variation which occurred in VFA concentrations between sequential samples, the coefficients of determination were extremely low and  no confidence could be assigned to the results of the analysis.  Apparently the rumen sampling procedure employed in the laboratory introduces substantial variation, mainly related to the difficulty in maintaining an anaerobic environment (J.H. Oh, personal communication). When this variation i s combined with that associated with individual deer due to diet, time since feeding, stage of digestion and other uncontrollable factors, an acceptable mathematical relationship could not be developed.  Since zero-time rates of VFA production could not be determined, parameters of rumen VFA were examined.  other  Other investigators (Prins and  Geelen 1971, Short 1963, 1971, Bruggemann et a l . 1968) have used the VFA concentration i n rumen contents as an indicator of seasonal forage quality in wild ruminants.  Research with domestic  ruminants  (Leng 1970, Weston  233  and Hogan 1968) has f u r t h e r shown that VFA production can be estimated from concentration once the r e l a t i o n s h i p of these items has been established  f o r the ruminant species of i n t e r e s t .  Because of v a r i a t i o n i n  t h i s r e l a t i o n s h i p and the v a r i a b i l i t y associated with feeding patterns of w i l d ruminants, Gasaway and Coady (1974) recommend using VFA concentration as an approximate i n d i c a t o r of fermentation rates; not as an estimator of VFA production.  To assess approximate rates of fermentation, seasonal VFA concentrations i n rumen contents were determined deer c o l l e c t i o n .  from a sample taken immediately  after  These values are presented i n Table 4-7. VFA concen-  t r a t i o n ranged from 8.83 to 13.87 mg VFA per 100 ml of rumen digesta and are comparable t o those observed  i n b l a c k - t a i l e d deer i n C a l i f o r n i a by  A l i o et a l . (1973), w h i t e - t a i l e d deer i n the southeastern U.S. by Short (1971) and moose i n Alaska by Gasaway and Coady (1974).  Statistical  comparisons i n d i c a t e VFA concentrations i n f a l l - w i n t e r are s i g n i f i c a n t l y lower than i n spring and summer which were not d i f f e r e n t .  The seasonal  change i n VFA concentration from 8.83 mg/100 ml i n f a l l - w i n t e r to over 13.5  mg/100 ml i n spring and summer corresponds  t o a range of 7.0-13.0  mg/100 ml observed during the year i n w h i t e - t a i l e d deer by Short (1971). These values r e f l e c t the c o n d i t i o n of the forages seasonally a v a i l a b l e as demonstrated with sheep by Hbgan et a l . (1969) where VFA concentrations ranged from 7.6 mg/100 ml f o r animals  on a d i e t of mature, high f i b r e  forage to 10.4 mg/100 ml on a d i e t of low f i b r e forage i n e a r l y stages of growth.  Skeen (1974) measured seasonal changes i n ruminal VFA concen-  t r a t i o n s i n w h i t e - t a i l e d deer but was not able to r e l a t e them to changes in  forage  quality  as indicated by l e v e l s of other n u t r i e n t s .  I n the  T a b l e 4-7.  Season  (n)  Seasonal comparisons o f VTA c o n c e n t r a t i o n , i n rumen contents o f b l a c k - t a i l e d deer.  VTA  Concentration (mg/100 ml)  :  a  Spring  Composition  composition and energy  value  Rumen Content  2  (percent)  digesta (kg)  VTA (moles)  energy (kcal)  3.6  7.4  2076.1  3  60.0  15.2  21.0  3.1  13.87 (1.26)  (733.9) 4  13.48°  Summer  62.7  15.0  20.1  2.1  5.0  10.2  12  62.6  8.83"  13.3  21.3  Number o f deer. Individual acids:  3.0  5.2  6.6  1847.6 (480.7)  (2.50)  1  2836.0 (708.5)  (1.15)  Tall-Winter  C = acetic, C = propionic, C = b u t y r i c and i s o b u t y r i c , C + = v a l e r i c , i s o v a l e r i c and h i g h e r a c i d s V a l u e s i n a column w i t h a common s u p e r s c r i p t l e t t e r a r e n o t d i f f e r e n t a t p < 0.05 l e v e l as determined by multiple t-test. ^Standard d e v i a t i o n .  2  2  5  3  ab  3  4  235  present  study,  fermentation  highest  ruminal  VFA concentration, indicating highest  rates coincided with periods of high forage quality as  indicated by high levels of crude protein content, DDM and cell contents (Figures 3-6, 3-7, 3-8).  Since individual VFAs have different caloric values, composition as well as concentration affects the energy value of ruminal VFAs.  A further  influence is the volume of rumen contents (rumen f i l l ) , which in combination with VFA composition and concentration affect the total caloric value of  the rumen digesta at any point in time.  It is recognized that rumen  f i l l varies with a number of factors including diet quality, time since eating and degree of digestion. of  Thus although i t is not a good indicator  short-term forage quality changes, rumen f i l l can help explain seasonal  trends in total ruminal energy as shown in Table 4-7. It should be noted that total energy in rumen contents is statistically different (p < 0.05) only between summer and fall-winter even though spring and fall-winter were also different i n VFA concentrations. Rumen f i l l is not different between summer and fall-winter and the difference in total caloric content observed  is a result of differences i n VFA concentration.  The even  greater differences in concentration in spring compared to fall-winter is offset by the reduced level of rumen f i l l in spring and these two seasons are not statistically different in total ruminal caloric content. VFA composition varied only slightly between seasons (Table 4-7) and thus had l i t t l e influence on seasonal differences observed in ruminal energy content.  236  SUMMARY - ENERGY VALUES AND VFA COMPOSITION OF FORAGE PLANTS  Observations on the energy content and VFA composition of forage plants and the manner in which they relate to other nutritional characteristics provides additional insight into patterns of forage use by deer.  These  observations can be summarized as follows:  1)  On an annual basis, forbs, as represented by Epilobium angustifolium, studied.  displayed highest energy  contents among the forages  Shrubs and conifers were intermediate and similar in  energy content.  Ferns and lichens displayed similar low energy  values.  2)  Consistent patterns, of  energy  content  related  to  area  of  collection were not observed in either forage types or species.  3)  In most forages, highest seasonal energy  values occurred in  summer, coinciding with peak levels of other nutrients.  This  pattern results in availability of energy being greatest during periods of lactation, and as fat and tissue reserves are being replenished prior to breeding and the winter period.  4)  The  lichen, Alectoria  sarmentosa, had lowest energy value of  the species examined. More VFA was produced in 48 compared to 24 hours of fermentation suggesting energy value of lichen may not be  realized  literature occur.  i f rumen turnover times  as reported in the  237  VFA composition of fermentation products varied seasonally with lowest levels of acetic acid in spring and highest levels in fall-winter in most species. Propionic acid levels were highest in fall-winter, not spring or summer as expected.  Higher acids  ( C 4 + ) generally reached peaks in spring and summer.  Relationships of energy and VFA measures to other characteristics of forage plants were variable.  In some types or species,  caloric value and propionic acid content were positively correlated with crude protein and dry matter digestibility as would be expected since high levels of a l l these variables indicate highly  nutritious  forage.  Acetic  and propionic acids were  consistently correlated in a negative fashion since one tends to increase at the expense of the other.  Although statistical correlation of food habits of deer with VFA characteristics was not feasible, forage selection patterns appeared  to be related to nutrient characteristics of plants.  During spring and summer deer selected plants high in caloric value, crude protein, cell contents and DDM.  In winter avail-  ability of forage seemed to have a greater influence on food selection than did nutrient content.  Efforts  to determine  zero-hour  fermentation  rates  through  sequential sampling of incubated rumen contents were not successful.  This was apparently the result of being unable to  maintain an anaerobic environment around the rumen coupled with variability patterns.  in rumen contents  associated with deer feeding  238  9)  VFA concentrations in deer rumen contents at time of collection were consistent with those observed in deer by other investigators. other  Seasonal  VFA concentrations followed a pattern like  measures of forage  occurred  quality,  i.e. peak concentrations  in spring and summer and were significantly higher  than winter concentrations.  10) Rumen f i l l  influenced total caloric content of rumen digesta.  In spring-summer comparisons, total caloric content was greater in  summer in spite of slightly higher VFA concentrations in  spring, since summer rumen f i l l was greater.  The analysis of VFA characteristics of forage plants and rumen digesta provided additional insight into patterns of forage use by deer. content,  Energy  as one indicator of nutritional value, appears to influence  forage selection within the overall framework defined by seasonal availability.  Phenological stage was shown to have a substantial influence on  levels of energy as i t did on other nutrients in forage plants.  239  LITERATURE CITED Alio, A.A., J.H. Oh, W.M. Longhurst, and G.E. Connolly. 1973. VFA production in the digestive systems of deer and sheep. J. Wildl. Manage. 37:202-211. Bath, I.H., and J.A.F. Rook. 1963. The evaluation of cattle food and diets in terms of the ruminal concentration of volatile fatty acids. I. The effects of level of intake, frequency of feeding, the ratio of hay to concentrates in the diet and of supplementary feeds. J. Agr. Sci. (Camb.) 61:341-348. Bruggeman, J., D. Giesecke, and K. Walser-Karst. 1968. Methods for studying microbial digestion in ruminants post mortem with special reference to wild species. J. Wildl. Manage. 31:198-207. Blaxter, K.L. 1961. Energy utilization in the ruminant. Pages 183-197 In: D. Lewis (ed.) Digestive physiology and nutrition of the ruminant. Butterworths, London. 297 pp. El-Shazly, K., and R.E. Hungate. 1966. Fermentation capacity as a measure of net growth of rumen microorganisms. Appl. Microbiol. 13:62-69. Gasaway, W.C., and J.W. Coady. 1974. Review of energy requirements and rumen fermentation in moose and other ruminants. Naturaliste Can. 101:227-262. Hogan, J.P., R.H. Weston and J.R. Lindsay. 1969. The digestion of pasture plants by sheep. IV. The digestion of Phalaris tuberosa at different stages of maturity. Aust. J. Agric. Res., 20:925-940. Hungate, R.E. 1966. The rumen and i t s microbes. New York. 533 pp.  Academic Press,  Leng, R.A. 1970. Formation and production of volatile fatty acids in the rumen, p. 406-421 In: A.T. Phillipson (ed.) Physiology of digestion and metabolism in the ruminant. Oriel Press Ltd., Newcastle upon Tyne, England. 636 pp. Mautz, W.W., and G.A. Petrides. 1971. Food passage rates in the white-tailed deer. J. Wildl. Manage. 35:723-731. Oh, J.H., M.B. Jones, W.M. Longhurst, and G.E. Connolly. 1970. Deer browsing and rumen microbial fermentation of Douglas-fir as affected by fertilization and growth stage. For. Sci. 16:21-27. Prins, R.A. and M.J.H. Geelen. 1971. deer, fallow deer, and roe deer.  Rumen characteristics of red J. Wildl. Manage. 35:673-680.  Short, H.L. 1963. Rumen fermentations and energy relationships in white-tailed deer. J. Wildl. Manage. 27:184-195.  240  Short, H.L. 1971. Forage digestibility and diet of deer on southern upland range. J. Wildl. Manage. 35(4):698-706. Short, H.L. 1975. Nutrition of southern deer i n different seasons. J. Wildl. Manage. 39:321-330. Short, H.L., D.R. Dietz, and R.E. Remmenga. 1966. Selected nutrients in mule deer browse plants. Ecology 47:222-229. Short, H.L., CA. Seqelquist, P.D. Goodrum and C E . Boyd. 1969. Rumino-reticular characteristics of deer on two food types. J. Wildl. Manage. 33:380-383. Skeen, J.E. 1974. The relationship of certain rumino-reticular and blood variables to the nutritional status of white-tailed deer. Ph.D. Thesis. Virginia Polytechnic Institute and State University. Blacksburg, Va. 98 pp. Ullrey, D.E., W.G. Youatt, H.E. Johnson, L.D. Fay, B.L. Schoepke, and W.T. Magee. 1970. Digestible and metabolizable energy requirements for winter maintenance of Michigan white-tailed does. J. Wildl. Manage. 34:863-869. Ullrey, D.E., W.G. Youatt, H.E. Johnson, A.B. Cowan, R.L. Covent, and W.T. Magee. 1972. Digestibility and estimated metabolizability of aspen browse for white-tailed deer. J. Wildl. Manage. 36:885-891. Weast, R.C, ed. 1968. Pages 184-189 In: Handbook of chemistry and physics, 49th ed. Chemical Rubber Co., Cleveland, Ohio. Weston, R.H., and J.P. Hogan. 1968. The digestion of pasture plants by sheep. I. Ruminal production of volatile fatty acids by sheep offered diets of ryegrass and forage oats. Aust. J. Agric. Res., 19:419-432.  241  CHAPTER V -  SEASONAL CHANGES IN CONDITION OF BLACK-TAILED DEER AND THEIR RELATIONSHIP TO PATTERNS OF FORAGE QUALITY  ABSTRACT  Physical condition of deer varies seasonally in response to forage availability and quality, to physiological demand associated with the reproductive cycle and to energy demands of the environment  associated with  changes in ambient temperature or ease of locomotion. Selected parameters of body weight and fat were examined to assess their relationship to condition of black-tailed deer collected at monthly intervals for one year. Levels of blood urea nitrogen (BUN) were determined to assess their relationship to protein-energy levels in the diet and to annual weight gain and  loss patterns.  females; f a l l  was  Fluctuations in weight  were greater in male than  the period of maximum weight while minimum weights  occurred in winter in both sexes.  Peak weights followed peaks in protein  and energy by several months and appeared to occur when energy demands above maintenance were lowest. Fat measures examined (back and mesentery fat  and kidney fat index - KFI) were closely correlated with each other  on a seasonal basis.  Mesentery fat and KFI appear to have the best poten-  t i a l as indicators of deer condition.  BUN varied significantly by season  with maximum values in spring coinciding with peak levels of protein in forage.  BUN levels decreased as protein decreased and energy content of  forages increased. directly  BUN  and rumen f i l l were negatively correlated in-  indicating a decline in BUN  as fibre levels in the diet in-  creased. Although weight losses of about 24 percent occurred over-winter, extensive tissue catabolism did not appear to occur since elevated BUN levels did not coincide with weight loss.  242  CHAPTER V - SEASONAL CHANGES IN CONDITION OF BLACK-TAILED DEER AND THEIR RELATIONSHIP TO PATTERNS OF FORAGE QUALITY  RATIONALE AND OBJECTIVES  The relative levels of nutrients available to herbivores vary with season and phenological stage of forage plants. These changes are manifested in changes in physical condition of deer as reflected in body weights and amounts of carcass fat. Compared to carcass fat measures, levels of ureanitrogen in blood respond protein levels.  on a shorter-term basis to changes in forage  Collection of animals  for in vitro t r i a l s provided an  opportunity to examine selected measures of carcass fat and blood ureanitrogen relative to forage quality patterns.  The objectives of measurement of parameters of physical condition of deer collected in this study were:  1)  To examine seasonal patterns of deposition and loss of selected types  of body fat relative to each other and to patterns of  nutritional value in forage species.  2)  To determine i f forage protein levels are reflected in levels of blood urea-nitrogen.  243  LITERATURE REVIEW  CARCASS FAT  The relationships of a number of body measures to the physical condition of wild ruminants have been examined in past research. involved direct or indirect measures of carcass fat.  Most work has  That fat measures  are meaningful indicators was discussed by Riney (1955:431) who postulated that "fat can be taken as a direct measure of the condition reflecting the metabolic levels or goodness of physiologic adjustment of an animal with its environment."  The most commonly used assessment of seasonal variation in fat reserves has been body and/or carcass weight (Leopold et al. 1951, Browning and Lauppe 1964). Taber and Dasmann (1958) employed this measure to determine black-tailed  deer condition and observed that in a non-migratory  population, carcass weight generally paralleled levels of forage protein. Jones (1975) calculated the linear regression of whole body weight on eviscerated weight for black-tailed winter.  Significantly-different  deer during a mild and a severe  slopes  were calculated  for the two  winters and indicated a greater whole body weight for a given eviscerated weight in the severe than in the mild winter.  Jones interpreted this  finding to mean a greater proportion of whole body weight was muscle and fat in the mild winter, indicating deer were in better condition than in the severe winter.  244  Eviscerated carcass weight was found to be a satisfactory index of carcass fat of female mule deer by Anderson et al. (1972).  This measure was not  suitable for mature males because of i t s strong relationship to age.  The  kidney fat index, calculated as the proportion of kidney fat to kidney weight less fat for both kidneys was recommended by Riney (1955) as the best measure of condition for red deer (Cervus elaphus). Ransom (1965) found that kidney fat was tailed deer but was  a good measure of condition in "fat" white-  of lesser value as condition declined, apparently  because of differential rates of depletion of kidney fat compared to fat in other locations.  Anderson et a l . (1972) found that the kidney fat  index correlated well with other carcass fat indices but was extremely variable when used to assess between-year differences in condition. They suggested the best use of kidney fat measures would probably be as an index to detect seasonal changes in mean carcass fat.  Dauphine (1971) observed that kidney fat and abdominal (mesenteric) fat were effective estimators over the entire range of condition of caribou (Rangifer tarandus) but provided a better condition estimate when combined with measures of back and femur marrow fat. As a result of later work, in which substantial seasonal fluctuations in kidney weight were observed, Dauphine (1975) concluded that the kidney fat index was valid only for intraseasonal (between year) comparisons  in caribou. Depth of  back fat was found to be an extremely variable measure of carcass fat by Anderson et a l . (1972) who suggested i t s use be limited to detection of seasonal changes in mean carcass fat. Based on this review, several of these techniques appear to be suitable for detecting seasonal, but not year to year changes in levels of body fat.  In the current study, several  of these fat measures were made to assess their comparative values as indicators of seasonal changes in physical condition of deer.  245  BLOOD UREA-NITROGEN (BUN)  Blood  serum levels of urea-nitrogen directly  reflect  dietary protein  intake and protein balance and are thus good indicators of protein status in Cervids (Le Resche et a l . 1974). relationship  for white-tailed deer  moose (Alces alces).  Seal et a l . (1972) observed this as did Houston (1969) for Shiras  Bailey (1969) reviewed  the literature on BUN and  concluded that high levels of BUN are favored by high levels of protein and  low levels  of easily-digested carbohydrates  i n the diet and by  catabolism of body protein. In captive white-tailed deer fawns, Buckland (1974) observed  that high levels of dietary protein significantly i n -  creased BUN values while high levels of energy in the diet significantly decreased them. BUN levels for deer on a high protein, high energy diet were elevated, but to a lesser degree than deer on a high protein, low energy diet.  Ullrey et a l . (1968) and Teeri et al. (1958) observed e l e  1  vated BUN levels related to protein catabolism associated with weight loss of white-tailed deer during winter.  Franzmann (1972) noted that  catabolism of body protein resulting in high BUN levels in bighorn sheep (Ovis canadensis) occurred at dietary protein levels of 5 percent.  METHODS  MEASURES OF ANIMAL CONDITION  Whole body weights of animals collected for in vitro trials were taken at the laboratory. Weights of deer collected i n remote locations.were taken in the field.  These are considered live weights as shooting resulted i n  246  only minor  losses of blood.  Field-dressed weights  (whole weight less  weight of viscera and blood) were taken after evisceration.  Weight of rumen contents was determined by subtracting weight of washed rumen tissue from total rumen weight as determined prior to sampling for in vitro t r i a l s .  A 50-ml blood sample was taken from the jugular vein immediately after the  animal was shot.  This sample was allowed to coagulate and approxi-  mately 5 to 10 mis of serum was decanted into a small vial and frozen for subsequent determination of blood-urea nitrogen.  Both kidneys were excised and fat surrounding the kidneys was"removed. Combined weights of both kidneys and fat were determined separately.  The mesentery  (greater and lesser omentum) surrounding the viscera was  removed by pulling i t away from i t s points of attachment to the organs and  body wall, and  i t s weight  determined.  This weight  included the  mesentery tissue and the depot fat i t contained.  An additional tissue sample was excised from the dorsal portion of the right hip, about 3 cm anterior to the base of the t a i l and immediately beside the spinal column.  This sample consisted of a 4-cm  square piece  of muscle tissue and fat; the thickness of the latter was measured at i t s two thickest points on i t s anterior surface to indicate depth of back fat.  Although specific examinations for abnormalties or parasites were  not made, they were recorded when encountered.  247  RESULTS AND DISCUSSION  The primary emphasis in this study was on the determination of digesti b i l i t y , energy and other nutrient characteristics of deer forage as they varied during the year and between areas of collection.  Deer were col-  lected primarily to provide a source of rumen inoculum for in vitro analyses  and  assessments.  to a lesser degree  for food habits and body condition  Thus, sample sizes are not as high as they would have been  i f emphasis was  on food habits or condition, and as a result definite  conclusions backed up by statistical analysis cannot be drawn in many instances.  Anderson et al. (1972) calculated numbers of samples required  for a given precision and confidence level in condition estimates. Their calculations  showed that  certain measures such as eviscerated carcass  weight could be adequately estimated with from 2 to 33 adult mule deer, the absolute number depending on the sex of the animal and the season. Substantially more males than females are required because of the greater variability in weights of males.  Measures such as kidney fat index and  depth of back fat, which vary substantially more than carcass weight, required from 88 to 532 and 381 to 2595 samples, respectively, during a season to provide the desired level of precision in the estimate. In light  of these requirements, statistical differences are d i f f i c u l t to  show in the limited  data presented here.  Nevertheless, some obvious  trends and relationships were observed which, when viewed in the context of similar information in the literature, seem to have biological meaning.  Seasonal designations are the same as those discussed in earlier chapters: spring (May and June), summer (July through September) and fall-winter (October through April). Values presented in the text are x (± SE x).  248  MEASURES OF BODY CONDITION  Live and Field-Dressed Weights  Seasonal live and field-dressed weights of male and female black-tailed deer are presented in Table 5-1.  A number of deer less than 1 year of  age are included in each sex class (9 males, 3 females); no deer less than 5 months old were collected.  Brown (1961) presented data for  Vancouver Island deer which indicated average field-dressed weights of 31.5 and 42.2 kg for adult females and males, respectively.  These were  hunter-killed deer taken in October and November. Average field-dressed weight of females, the group best represented in the present study, was 27.1  (± 1.13)  kg.  This weight is probably comparable  to the 31.5 kg  weight Brown reports; the slightly lower value probably results from the inclusion of some females less than 1 year old, as well as deer taken during late winter after weight losses had occurred. Similarly, the lower weights for males results from the inclusion of deer less than 1 year old in the present study.  Live weights and field-dressed weights were higher in summer than in the other seasons but the differences were not statistically significant (p < 0.05).  The grouping of months into seasons tends to obscure the actual  pattern of weight gain and loss as shown when monthly values are plotted (Figure 5-1). tinct  When these patterns of weight change are examined a dis-  trend is evident and  working  with species  is comparable  of Odocoileus  to that reported by others  (Brown 1961,  Robinette et al. 1973, and Short et a l . 1969).  Wood et a l . 1962,  Table 5-1. Seasonal p a t t e r n s i n s e l e c t e d morphological parameters and measures of body c o n d i t i o n i n male and female b l a c k - t a i l e d deer.  Season  L i v e Weight - (kg) —  n  Field-Dressed Weight — (kg)  Weight R a t i o  25.5 ( 6.9)  0.70 (0.05)  Mesentery Weight - (g) "  Back F a t - (mm) -  1  Kidney F a t Index 2  Spring Males  4  Females  9  Males and Females  13  ' 36.8 ( 1 1 . 4 )  3  39.8 ( 9 . 1 )  4  a  27.3 ( 6.1)  a  0.69 (0.04)  a  1.,1 (0.4)  33.9 ( 18.3)  1.,2 (0.1)  85.2 ( 66.8)  1.75 (2.4)  0.69 (0.04)  28.1 ( 5.9)  41.1 ( 8.4) a  0.5 (0.0) 1.3 (2.0)  a  68.1 ( 59.8)  a  l . ,1 (0.1)  Summer Males  5  Females  10  Males and Females  15  41.3 (10.2) a  42.2 (11.9)  a  4.9 (8.8)  0.71 (0.01)  33.9 (12.1)  44.3 (16.3)  30.0 ( 3.3)  0.68 (0.04)  31.5 ( 7.7)  . 0.69 (0.04)  24..8 (16.2)  0.69 (0.3)  a  2.8 (3.2) a  3.4  (5.1)  b  243.0 (338.7)  1,.4 (0.6)  151.8 ( 93.1)  1..3 (0.3) .3 (0.4)  182.2 (200.7)  Fall-Winter Males  21  Females  29  Males and Females  50  35..9 (16.3) 39,.2 ( 9.6)  0.67 (0.67)  27..1 ( 6.1)  40..5 ( 7.7) a  a  26..0 (13.0)  a  0.68 (0.06)  a  0.5  (0.0)  4.3  (5.8)  3.3  (5.2)  2..1 (1.6)  44.4 ( 50.0)  1..6 (1.0)  132.6 (119.3) ab  1 0 8 . 2 (111.4)  b  l . .8 (1.2)  Weight r a t i o = f i e l d dressed weight / l i v e weight K i d n e y f a t index = weight of kidneys p l u s weight of f a t / weight o f kidneys. ^Standard d e v i a t i o n . Combined male and female means s h a r i n g a common s u p e r s c r i p t (abc) are not s t a t i s t i c a l l y d i f f e r e n t a t p < 0.05 as determined by a n a l y s i s o f v a r i a n c e and Scheffe's t e s t . 1  2  4  250  Weight  (kg) 50  50  l i v e weight  40  •  30  L  j  ;;0  X  field-dressed  Mesentery Weight  300  -H  &-  weight  Back Fat Depth  (g) back f a t depth  mesentery weight  H- 9  «  100  fat  B-  6  r  3  Weight R a t i o  Kidney F a t Index kidney wt. +  (mm)  12  /  J  200  30  ,o- .-C  20  -a  X)  /  -|  400  40  N,  field-dressed weight  3  CV  *  " weight r a t i o  wt.  l i v e weight  \  kidney wt.  _  A  .  ^ k i d n e y f a t index  month: n:-3  Figure 5-1.  J  F 5 7  M  A  M 5  J 6  J A S 6  3 1 0 1  O N D 2 3  4  Monthly patterns of v a r i a t i o n i n s e l e c t e d morphological parameters and measures of body c o n d i t i o n i n b l a c k - t a i l e d deer of mixed ages and sex.  1  251  Percentage weight loss during the winter was calculated by subtracting weights in the period of minimum weight (February-April) from the weight during the period of maximum weight (September-January) about 24 percent.  and amounted to  This is higher than the average 10.3 percent loss  reported by Brown for captive black-tailed deer in western Washington. However, Brown's deer had access to supplemental feed. Bandy (1965) and Short et a l . (1969) reported voluntary decreases in food consumption in winter by black-tailed and white-tailed deer, respectively.  These in-  vestigators observed over-winter body weight losses of up to 25 percent associated with these declines in food intake.  Over-winter weight losses were greater in males than females (Table 5-1) but due to small sample sizes were not statistically different. Greater fluctuations in weights of males have been documented for black-tailed deer (Brown 1961, Nordan et a l . 1970) and for red deer Cervus elaphus (Mitchell et a l . 1976).  Anderson et a l . (1972) reported that weight and  other condition indices were generally higher in female than in male mule deer in winter.  Deer reached maximum weight in early f a l l and minimum  weights were observed in late winter (Figure 5-1).  This pattern is con-  sistent with that observed by Brown (1961) for black-tailed deer and Anderson et a l . (1972) for mule deer.  In the latter instance maximum  weights occurred at the beginning of the breeding period when both males and females were judged to be in peak condition. Taber and Dasmann (1958) observed that peak condition as indicated by carcass weight in blacktailed deer coincided with peak protein levels in forage. In the current study, and that of Anderson et al. (1972), forage protein in most species peaked  in spring (May and June) (Figures 3-6, 3-7, 3-8), while carcass  252  weights were highest in autumn. In fact, deer condition was at i t s lowest level at or just prior to the time of peak forage protein levels (Figure 5-1).  Short (1975) observed this pattern in white-tailed deer and specu-  lated that:  "... in late spring and early summer the requirements for recovery of winter weight  loss, antlerogenesis, growth, late gestation and  lactation are great. production.  L i t t l e digestible energy is available for fat  Apparently in late summer and early autumn the demands  above maintenance requirements  are comparatively few, and deer  may  be in a physiological state favoring lipOgenesis so that extensive fat deposition can occur i f proper energy sources are available."  Levels of energy production from volatile fatty acids in the rumen (Table 4-7) and from fermentation of forage plants (Figures 4-1, 4-2, 4-3) in most cases were greatest during the summer period (July-September) and support Short's (1975) presumption regarding availability of energy.  The ratio of field-dressed weight to live weight was not significantly different between seasons year-long basis.  (Table 5-1)  and showed l i t t l e variation on a  Using regression techniques Jones  (1975) observed a  lower ratio in a severe winter compared to a mild winter. In the present study, the slightly lower field-dressed:live weight ratios seen i n April and December-January reflect losses of fat as also revealed by reduction in other fat measures.  It would seem that for pregnant females, weight  of the uterus and i t s contents would confound the meaning of the weight ratios.  Because of small sample sizes, this interaction was not examined  in the present study.  253  Back Fat, Mesentery Fat and Kidney Fat Index (KFI)  These factors were measured to examine their relationship to body condition and to nutrient characteristics of forage species.  Among these  and other measures, the kidney fat index has been most widely used as an estimator of body condition.  Seasonal levels  of back fat depth, mesentery fat weight and KFI are  presented and statistically compared in Table 5-1.  Monthly patterns of  variation in these measures are shown in Figure 5-1.  In terms of per-  centage change a l l of these measures tend to fluctuate more widely over the course of a year than do live or field-dressed weights (Anderson et al. 1972, Mitchell et a l . 1976).  Although differences in depth of back  fat were not significant between seasons there was clearly a trend that followed pattern of body weight change. In male deer, back fat was essent i a l l y absent during spring and fall-winter, reflecting the utilization of depot fat associated with increased activity and reduced food intake during the rut. was  Back fat in females was not depleted to the extent i t  in males during these seasons.  Males accumulate  fat more rapidly  than females during summer, probably since they are free from demands of lactation, as shown by the greater depths of back fat at this time (Table 5-1).  Back fat proved to be a highly variable measure as reported by Mitchell et aJL. (1976) who noted rump fat was present only when red deer had large amounts of internal body fat. Anderson et a l . (1972) found that a large percentage of the deer they sampled were without measurable  back fat.  254  The prolonged period (4 months) during which back f a t was absent i n the current study probably reduces i t s u t i l i t y as a condition i n d i c a t o r .  Mesentery weight was  s i g n i f i c a n t l y higher i n summer then i n spring f o r  male and female b l a c k - t a i l e d deer combined  (Table 5-1).  As was observed  with depth of back f a t , females had more mesentery f a t than males i n a l l seasons except summer, probably since does were l a c t a t i n g at t h i s time. Monthly patterns of v a r i a t i o n i n mesentery weight are shown i n Figure 5-1.  Mesentery f a t weight c l o s e l y followed the pattern of back f a t depth  with which i t was c l o s e l y correlated (Table 5-2).  Actual weights v a r i e d  from 24.8 (± 2.0) g i n A p r i l , i n which no depot f a t was v i s i b l e , to 341.5 (± 74.5) g i n October.  Mesentery f a t weight was s i g n i f i c a n t l y correlated  to both l i v e weight and f i e l d - d r e s s e d weight (Table 5-2) with the highest r  values,  highest.  0.88  and  0.91,  respectively,  Recognizing the small  sample  i n summer when weights were size  and  the observation that  mesentery f a t weight undergoes s u b s t a n t i a l v a r i a t i o n throughout the year, it  still  appears to have p o t e n t i a l as an i n d i c a t o r of body condition.  More work with l a r g e r samples i s needed to determine i t s u t i l i t y .  Seasonal l e v e l s of KFI are presented i n Table 5-1. ences  (p < 0.05)  were observed beween spring  Significant differ-  and f a l l - w i n t e r ; summer  l e v e l s were not d i f f e r e n t from the other two seasons.  Highest average  KFI f o r male and female deer combined occurred i n the f a l l - w i n t e r period and generally coincided w i t h the peaks i n other f a t measures and body weights as displayed  i n Figure 5-1.  Other i n v e s t i g a t o r s  (Riney 1955,  Taber et a l . 1959, M i t c h e l l 1976) have found KFI s u i t a b l e as an i n d i c a t o r of body condition.  However, recent work by Dauphine  (1975) i n which he  255  Table 5-2. Correlations of selected morphological parameters and measures of body condition in black-tailed deer. Only significant (p < 0.05) values are listed. Correlations are for deer from a l l age and sex classes and forested and cutover areas combined.  Correlation of  Spring (n = 12)  Summer (n = 14)  Fall-Winter (n = 29)  0.97 0.73 0.61  0.98 0.88 0.83  0.95 0.52 0.42  0.77 0.62  0.91 0.89  0.52 0.55  0.91 0.92  0.93 0.85  0.88 0.80  0.91  0.89  0.91  Live weight with: field-dressed weight mesentery weight kidney fat index  Field-dressed weight with: mesentery weight kidney fat index  Mesentery weight with: kidney fat index back fat depth  Kidney fat index with: back fat depth  256  observed  statistically  significant  seasonal changes in kidney size of  caribou points out some previously unrecognized problems with this technique.  The assumption employed i n using the index is that kidney weight  varies in a constant fashion with body size.  However, since changes in  kidney weight occur seasonally in caribou, Dauphine (1975) concluded i t was unsuitable as an index to reflect seasonal changes i n another physical attribute such as body size.  That a similar problem occurs in deer  is shown by Dauphine* s calculation of the data of Taber et a l . (1959) from mule deer showing as much as a 22 percent difference between summer and winter kidney weights.  In the present study kidney weights varied a  maximum of 27 percent between summer and fall-winter, however, age distribution of the sample deer varied between these seasons and probably accounted  for some of this  difference.  Because of these  problems,  Dauphine (1975) recommends the KFI be adjusted for seasonal changes i n kidney weight before i t i s used for seasonal comparisons  of body condi-  tion.  The simple seasonal correlations of the several body condition parameters discussed above are displayed in Table 5-2. A l l of the relationships examined were significant high  (p < 0.05) and correlation coefficients were  in nearly a l l cases.  This observation i s similar to those of  Anderson et a l . (1972) who interpreted the significant correlation to suggest that the fat indices chosen were f a i r l y synchronous on a yearlong basis.  The best relationships between either live or field-dressed  weight and the other condition indices examined occurred in summer. The reason for summer correlations are highest i s not clear since month-tomonth variation i n a l l variables during summer appeared as great as in other seasons.  257  Blood-Urea Nitrogen  (BUN)  Seasonal levels of BUN Table 5-3.  in blood serum of black-tailed deer are listed in  Values are for a l l deer collected in each season as s t a t i s t i -  cal comparisons indicated there were no differences age  or sex classes.  Seal and Erickson  (p < 0.05)  (Table 5-3).  differences in BUN  between  (1969) also noted this lack of  difference due to sex and age in white-tailed deer. nificant  (p < 0.05)  occurred  Statistically sig-  between a l l 3 seasons  Skeen (1974) noted significant seasonal differences in BUN  in wild white-tailed deer as did Seal et a l . (1972) working with pregnant white-tailed deer in captivity.  A direct relationship between levels of protein in forage and BUN concentration has been shown in most wild ruminants and also occurred  in the  present study. This relationship is shown in Figure 5-2 in which monthly levels of BUN  and crude protein of rumen contents are plotted.  As dis-  cussed in Chapter III, crude protein of rumen contents reflected patterns of crude protein in forage.  Correlation analysis indicated crude protein  of rumen contents and BUN were significantly (p < 0.05) (r = 0.72)  and fall-winter (r = 0.75)  for the sharp decline in BUN  related in summer  but not during spring.  The reason  in June, compared to the relatively minor  reduction in ruminal crude protein is not apparent. There may have been some relationship to reproductive sample were adult  females  that  state as 3 of the 4 animals in the had  recently  given  birth  to  fawns.  Placental tissues were present in the rumens of 2 of these does but their effect should have been to increase BUN. served significantly higher BUN  Le Resche et a l . (1974) ob-  levels in cow moose with calves compared  258  T a b l e 5-3.  Season  Spring  Seasonal l e v e l s o f b l o o d urea n i t r o g e n (BUN) and ruminal crude p r o t e i n i n b l a c k - t a i l e d deer.  Rumen Crude Protein (%)  n  BUN (mg/100 ml)  n  10  25.8 (8.8)  12  38.7 (4.2)  a  14  27.7 (9.3)  b  27  17.4° (5.3)  a i  Summer  11  15.9 (6.1)  Fall-Winter  26  7.4 (7.1)  2  b  C  d e n o t e s s t a t i s t i c a l s i g n i f i c a n c e as determined by a n a l y s i s of v a r i a n c e and S c h e f f e ' s t e s t . Means w i t h i n a column having a common s u p e r s c r i p t (abc) a r e n o t d i f f e r e n t (p < 0.05). Standard deviation.  2  259  Figure 5 - 2 .  Monthly l e v e l s of blood-urea n i t r o g e n and ruminal crude p r o t e i n i n b l a c k - t a i l e d deer.  260  to those without calves but were unable to determine the reasons for the difference.  The  relationship of BUN  to energy content of the diet seemed to follow  the pattern observed by Kirkpatrick et al. (1975) for captive white-tailed deer, in which BUN was influenced positively by protein and negatively by energy in the  diet.  The  peak in BUN  protein level in most forage species  in May  corresponds to the peak  (Figures 3-6,  3-7,  3-8) while de-  clines in BUN in July and August coincide with peak energy values of most forage species as well as declining levels of crude protein. declines in BUN  and  The further  rumen crude protein content which occur during the  fall-winter probably result from the increased levels of fibre in forage plants during this period (Table 3-8).  The significant negative corre-  lation observed between rumen f i l l , which generally reflects high fibre levels in the diet, and BUN  in fall-winter (r = -0.66) and summer (r =  -0.71) further supports this observation. (r < -0.5) but significant (p < 0.05) fibre in the rumen and BUN  negative correlations between crude  during f a l l and winter in white-tailed deer  in the southeastern United States. noted for BUN  Buckland (1974) observed low  Positive correlations (r < 0.5) were  and rumen crude protein contents; higher correlations were  expected because of the significant relationship shown between protein intake and BUN.  This departure from the expected results may  possibly  have been a function of the captive feeding situation or the experimental diets selected. in the  Skeen (1974) working with wild male white-tailed deer  southeastern United  States observed a much better relationship  (r = 0.76) between BUN and crude protein in forage.  261  Elevated levels of BUN can result from both increased protein intake or increased tissue catabolism.  Whether the source of amino acids is the  diet or body tissue, in the absence of high energy levels ammonia i s formed by microbial action in the rumen, absorbed through the rumen wall and transported via the circulatory system to the liver where i t is converted to urea.  Most urea is subject to urinary excretion but most rumi-  nants including deer (Robbins et a l . 1974) have the capacity to recycle urea as a nitrogen source during periods of low protein intake. Because of this ability to recycle urea, the level of dietary protein at which tissue catabolism begins has not been clearly defined for deer. Franzmann (1972) determined that high levels of BUN resulting from tissue catabolism in bighorn sheep occurred at dietary protein levels of 5 percent. (1978) recorded  that tissue catabolism  mg/100 ml in bighorn  increased BUN from 8.5 to 24.2  sheep maintained on a diet of 2-3 percent  protein for a 4-month period.  Hebert  crude  de Calesta et a l . (1977) measured the  levels of BUN i n mule deer which (1) were on diets which maintained body weight, (2) lost weight as a result of food deprivation, and (3) died as a result of starvation. A large increase in BUN was observed only between group 3 and the other 2 groups.  In deer which starved, BUN levels were  about 41 percent, while BUN ranged from 8 to 27 percent groups.  de Calesta  (1977) speculated  i n the other  that even though catabolism of  muscle protein may have occurred in group 2 the expected increase in BUN did not occur, probably because i t was offset by a BUN reduction as a result of reduced protein intake.  Ullrey et a l . (1975) observed a decrease in BUN from 14.3 to 9.9 mg/100 ml as a result of consumption of a high protein supplement, and suggested  262  this change was a result of decreased tissue catabolism or an increase in the net utilization of nitrogen.  Average monthly BUN ranged from 4.0 ml in May  levels  in black-tailed deer in the present study  (±0.5) in February and December to 30.0  (Figure 5-2).  (± 3.4) mg/100  Skeen (1974) observed a range of 8.8 to 34.7,  with a winter mean of 17.6 mg/100 ml in white-tailed deer.  Le Resche et  a l. (1974) recorded BUN concentrations ranging from 4.0 to 32.0 mg/100 ml in moose in Alaska.  These values are quite similar and probably approximate the range of BUN levels occurring in Northern American cervids in the absence of severe nutritional  stress.  The  degree to which tissue catabolism influences  these values in unknown, but in the current study i t does not appear to have occurred since BUN levels were lowest during the period of greatest weight loss.  SUMMARY - MEASURES OF BODY CONDITION AND BLOOD UREA NITROGEN  Observations made during this segment of the study can be summarized as follows:  1)  Weights  recorded  in the study were comparable to those pre-  viously recorded for black-tailed deer on Vancouver Island.  2)  Weight losses observed during winter were of the same general magnitude as those reported for other Qdocoileus species.  263  Annual  patterns  of  weight  change compared  closely  to those  observed in black-tailed deer by other investigators.  Fluctuations to be  in weight and other measures of condition tended  greater  in males than  females; during winter females  generally had higher levels of back fat and mesentery weight than males.  Maximum weights of deer of both sexes occurred in fall-early winter; minimums occurred in late winter (March).  Occurrence  of peak weights seemed to be associated with the  period of the year when energy demands above maintenance were lowest; minimum weights  occurred just  prior  to peak protein  levels in forage. A delay in response to improved protein and energy  conditions  in forage probably reflected  recovery from  winter nutritional stress and the demands of gestation, lactation and antler growth.  Fluctuations  in the variables  selected to reflect  condition,  i.e. kidney fat index, depth of back fat and mesentery weight, were  much  greater percentage-wise  than  fluctuations  in body  weight.  Depth  of back  fat and  correlated; mesentery  weight of mesentery  fat were closely  fat is not as variable as back fat and  appears to have better potential as a body condition indicator.  264  Kidney fat index appears  to be a reasonably good indicator of  body condition; adjustments  to compensate for seasonal differ-  ences in kidney weight are necessary i f KFI is to be used to reflect seasonal changes in condition.  Seasonal fat  correlation of KFI, mesentery fat and depth of back  with  each other were consistently  significant  suggesting  these measures are f a i r l y synchronous on a year-long basis.  BUN concentrations observed i n the study compared closely with those reported for other North American cervids.  Seasonal  differences i n BUN levels were statistically s i g n i f i -  cant; highest levels  occurred i n spring and minimums occurred  in fall-winter.  Levels  of BUN and forage protein were closely  related; both  measures reached peak levels in June.  Consistent with literature observations that BUN decreases with high energy-low protein diets, BUN concentrations were low i n late summer when energy values of forage plants are highest and protein levels had declined substantially from peak values in spring.  Rumen f i l l cating  and BUN were negatively correlated, indirectly indi-  a decline i n BUN with  digestibility of forage plants.  increased  fibre  and  reduced  265  16)  Levels of dietary protein at which tissue catabolism takes place in deer are not known; the range of BUN  levels observed relative  to temporal changes in forage protein provided no clear indication that  catabolism was  responsible for elevated BUN  at  any  time during the year.  17)  BUN  is a fairly  in black-tailed  reliable indicator of level of protein deer at  least at protein  intake  intake levels above  that required for maintenance.  Temporal patterns of variation in weights and other measures of body condition in black-tailed deer were seen to be related to patterns of variation  in nutritional value  of  forage plants.  Kidney  fat  index  and  mesentery weight appear to have u t i l i t y as condition indicators, at least at the extremes of fluctuation of body weight. closely  related  to protein  levels  Blood urea nitrogen  in forage as  indicated  by  was  ruminal  protein levels, and provides a good indicator of recent level of protein intake in black-tailed deer.  In this regard BUN has potential as a method  of assessing temporal or spatial differences in range quality.  266  LITERATURE CITED J.A. Bailey. 1969. Rumino-reticular contents and blood constituents as parameters of nutritional condition in North American deer, pp. 94-117 In: Recent Advances in Wildlife Nutrition. Papers from a graduate seminar. Colorado State University. 178 pp. Bandy, P.J. 1965. A study of comparative growth in four races of black-tailed deer. Ph.D. thesis. Dept of Zoology. University of British Columbia. Vancouver. 189 pp. Brown, E.R. 1961. The black-tailed deer of western Washington. Washington State Game Dept. Biol. Bull. No. 13. 124 pp. Browning, B.M. and E.M. Lauppe. 1964. A deer study in a redwoodDouglas-fir forest type. Calif. Fish and Game 50:132-147. Buckland, D.E. 1974. Blood urea nitrogen levels of white-tailed deer as an index of condition and nutritional intake. M.S. thesis, Virginia Polytechnic Institute and State University. Blacksburg, Virginia. 48 pp. Dauphine, T.C., Jr. 1971. Physical variables as an index to condition in barren-ground caribou. Trans. N.E. Sect. Wildl. Soc. 28:91-108. Dauphine, T.C., Jr. 1975. Kidney weight fluctuations affecting the kidney fat index in caribou. J. Wildl. Manage. 39:379-386. de Calesta, D.S., J.G. Nagy and J.A. Bailey. 1977. Experiments on starvation and recovery of mule deer does. J. Wildl. Manage. 41:81-86. Franzmann, A.W. 1972. Environmental sources of bighorn sheep physiologic values. J. Wildl. Manage. 36:924-932. Hebert, D.M. 1978. Blood chemistry as an indicator of nutritional condition in bighorn sheep. Proc. of the 1978 Northern Wild Sheep and Goat Conference. Penticton, B.C. April 2-4, 1978. p. 365-387. Houston, D.B. 1969. A note on the blood chemistry of the Shiras moose. J. Mammal. 50:826. Jones, G.W. 1975. Aspects of the winter ecology of black-tailed deer (Odocoileus hemionus columbianus IRichardsonl) on northern Vancouver Island. M.S. thesis, Faculty of Forestry, Univ. of British Columbia. 75 pp. Kirkpatrick, R.L., D.E. Buckland, W.A. Abler, P.F. Scanlon, J.B. Whelan and H.E. Burkhart. 1975. Energy and protein influences on blood urea nitrogen of white-tailed deer fawns. J. Wildl. Manage. 39:692-698. Leopold, A.S., T. Riney, R. McCain and L. Tevis, Jr. 1951. The jawbone deer herd. Calif. Dept. of Fish and Game. Game Bull. No. 4. 139 pp.  267  LeResche, R.E., U.S. Seal, P.D. Karns and A.W. Franzmann. 1974. A review of blood chemistry of moose and other Cervidae with emphasis on nutritional assessment. Naturaliste Can. 101:263-290. Mitchell, B., D. McCowan and I.A. Nicholson. 1976. Annual cycles of body weight and condition i n Scottish red deer, Cervus elaphus. J. Zool. Lond. 180:107-127. Nordan, H.C., I. McT. Cowan, and A.J. Wood. 1970. The feed intake and heat production of the young black-tailed deer (Qdocoileus hemionus columbianus). Canadian J. Zool. 48:275-282. Ransom, A.B. 1965. Kidney and marrow fat as indicators of white-tailed deer condition. J. Wildl. Manage. 29:397-398. Riney, T. 1955. Evaluating condition of free ranging red deer (Cervus elaphus), with special reference to New Zealand. New Zealand J. Sci. Technol. 36:429-463. Robbins, C.T., R.L. Prior, A.N. Moen, and W.J. Visek. 1974. Nitrogen metabolism of white-tailed deer. J. Anim. Sci. 38:186-191. Robinette, W.L., CH. Baer, R.E. Pillmore and C.E. Knittle. 1973. Effects of nutritional change on captive mule deer. J. Wildl. Manage. 37:312-326. Seal, U.S. and A.W. Erickson. 1969. Hematology, blood chemistry and protein polymorphisms in the white-tailed deer (Qdocoileus virginianus). Comp. Biochem. Physiol. 30:695-713. Seal, U.S., L.J. Verme, J.J. Ozoga and A.W. Erickson. 1972. Nutritional effects on thyroid activity and blood of white-tailed deer. J. Wildl. Manage. 36:1041-1052. Short, H.L. 1975. Nutrition of southern deer i n different seasons. J. Wildl. Manage. 39:321-330. Short, H.L., J.D. Newsom, G.L. McCoy, and J.E. Fowler. 1969. Effects of nutrition and climate on southern deer. Trans. N. Am. Wildl. Nat. Resour. Conf. 34:137-145. Skeen, J.E. 1974. The relationship of certain rumino-reticular and blood variables to the nutritional status of white-tailed deer. , Ph.D. thesis. Virginia Polytechnic Institute and State University. Blacksburg, Virginia. 98 pp. Taber, R.D. and R.F. Dasmann. 1958. The black-tailed deer of the chaparral. Calif. Dept. of Fish and Game. Game Bull. No. 8: 163 pp. Taber, R.D., K.L. White and N.S. Smith. 1960. The annual cycle of condition in the rattlesnake, Montana mule deer. Proc. Mont. Acad. Sci. 19:72-79.  Teeri, A.E., W. Virchow, N.F. Colovos, and F. Greeley. 1958. Blood composition of white-tailed deer. J. Mammal. 39:269-274. Ullrey, D.E., W.G. Youatt, H.E. Johnson, L.D. Fay, R.L. Covert and W.T. Magee. 1975. Consumption of a r t i f i c i a l browse supplements by penned white-tailed deer. J. Wildl. Manage. 39:699-704. Ullrey, D.E., W.G. Youatt, H.E. Johnson, L.D. Fay, B.E. Brent, and K.E. Kemp. 1968. Digestibility of cedar and balsam f i r browse for white-tailed deer. J. Wildl. Manage. 32:162-171. Wood, A.J., I. McT. Cowan, and H.C. Nordan. 1962. Periodicity of growth in ungulates as shown by deer of the genus Qdocoileus. Canadian J. Zool. 40:593-603.  269  CHAPTER VI - MATURE FORESTS, LITTERFALL AND PATTERNS OF FORAGE QUALITY AS FACTORS IN THE NUTRITION OF BLACK-TAILED DEER ON NORTHERN VANCOUVER ISLAND  SUMMARY, MANAGEMENT AND RESEARCH IMPLICATIONS  Findings of this study have implications to both foraging theory and practical management. Optimal foraging theory was developed by MacArthur and Pianka  (1966) and, in essence, states that animals will  select  forages on the basis of quality and relative frequency of occurrence in the environment. vironment  As the density of forages of high quality in the en-  increases,  the number of species selected declines.  This  theory has subsequently been presented in different algebraic form by a number of workers from Schoener (1971) through Charnov (1976).  It has  proven useful i n interpreting the foraging behavior of granivores and carnivores (see reviews of Pyke et a l . 1977, Krebs 1978).  Ruminants,  however, invariably depart from the predictions of current theory; spec i f i c a l l y they ingest more forage species of lower quality than is predicted.  To date  the only successful  application of the theory of  "optimal diet selection" to a ruminant has been that of Belovsky (1978) for moose (Alces alces).  Belovsky was successful only because he con-  strained the optimality function to incorporate a minimum level of sodium in the diet.  Sodium was known to be limiting to moose in the study area  (Jordan et al. 1973), thus Belovsky's findings may s t i l l reflect a departure from optimal foraging theory.  In a l l other studies of ruminant  foraging there has been no clear reason why the animals should depart so  t 270  markedly  from  optimality.  The recent conceptual  refinements  of the  theory  (e.g. Pulliam 1975) do not allow the observed variety in the  diet.  My results (Tables 3-11, 3-12) indicate a definite synergistic  effect of mixed diets and suggest that the variability i s required for proper rumen function. The observation that rumens s t i l l contained an average of 7-8 species per rumen, even in spring and summer when ample forage of the most digestible species was present, supports the concept of requisite variety.  Implications for management are those related to the status of blacktailed deer populations as they are affected by the harvest of mature forests and their replacement with plantations. The potential influences on forage selection and quality are apparent  i n Table 6-1 which sum-  marizes the comparison of cutover and forested areas using data on food habits (Figure 3-3), crude protein and digestibility (Table 3-3), and energy content (Table 4-3). Potential diets incorporate only the three or four most important contributors to deer diets based on percent importance value observed in each season.  In a l l cases, except cutovers  in fall-winter, these species contributed more than 79 percent of the dietary importance value.  Based on forage quality alone, i t is apparent from Table 6-1 that cutovers are more important than forested areas as sources of food.  Poten-  t i a l energy and crude protein contents and DDM are higher in plants in cutovers in a l l seasons.  However, these results are potentially mis-  leading i f the effects of snowfall on food availability are not considered (Figure 2-2).  Jones (1975) presented data indicating snow depths  Table 6-1. Seasonal characteristics (energy, crude protein and digestible dry matter content) of primary forages consumed by black-tailed deer in forested and cutover areas. 3  Spring Forested  Forage Characteristic  Summer  Cutover  Forested  — Fall-Winter —  Cutover  Forested  Cutover  Annual Forested  Cutover  3.3  3.7  3.2  4.8  1.4  1.9  1.8  2.9  Crude protein (%)  18.8  20.9  8.1  13.3  7.2  10.2  7.2  10.2  Digestible dry matter (%)  50.5  65.2  40.7  70.2  49.6  61.6  49.6  6.1.6  Energy content (kcal/0.8 g)  Combination of plant species making up majority of forage consumed in cutover or forested areas. Values are weighted according to their percent Importance Value (IV) as determined in rumen content analyses, Diets consist of: Spring:  Forested - Rubus spp. IV = 65, Vaccinium spp. IV - 10, Tsuga heterophylla IV = 5  Spring:  Cutover  Summer:  Forested - samples not collected - assumption made that Vaccinium spp., Gaultheria shallon and Thuja plicata a l l occurred at IV = 33  Summer:  Cutover  - Epilobium angustifolium IV = 47, Rubus spp. IV = 18, Cornus canadensis IV = 15  - Epilobium angustifolium IV = 66, Rubus spp: IV = 12, Vaccinium spp. IV = 6  Fall-Winter:  Forested - Alectoria sarmentosa IV = 42, Gaultheria shallon IV = 37, Thuja plicata IV - 6, Tsuga heterophylla IV = 4  Fall-Winter:  Cutover  - Epilobium angustifolium IV = 31, Gaultheria shallon IV = 19, Blechnum spicant IV Thuja plicata IV = 5  2 72  in cutovers were twice those in areas of mature forests, and that deer use of cutovers was precluded when accumulations of soft snow reached depths of 50 cm. Bloom (1978) reported a similar situation in southeast Alaska.  That  snow depth  was the primary  factor confining deer to  forested areas was illustrated by Jones (1975) who observed a dramatic increase in deer use of cutover areas under conditions of crusted snow which permitted deer to travel on the snow surface. Under conditions of deep soft snow, quality and quantity of forage in cutovers is of l i t t l e consequence, because i t is inaccessible, while l i t t e r f a l l  and rooted  plants continue to supply forage in mature stands (Figure 2-2, 2-3). Harestad  (1979) measured substantially higher levels of available food  in winter in most mature forest types compared to cutover areas.  Indices of physical condition of deer indicate that black-tailed deer in the Nimpkish Valley entered the winter period in relatively good condition but even in the relatively mild winter of the study period condition deteriorated markedly (Figure 5-1).  Data of Jones (1975) document that  deterioration i n condition i s much more severe in a winter of deep snow compared to one of lesser snow depth.  Together, these observations have  several implications to both forest and wildlife management.  With continued harvesting of mature forest at mid- and low-elevation the capacity of the range to support deer populations during severe winters is  reduced.  Options under the control of forest and wildlife managers  include the temporary reservation of selected mature stands until adjacent second-growth forests develop reduced snow depths.  a structure which w i l l result i n  Although the physical structure of second-growth  273  stands required to achieve reduced snow depths is not currently well defined, measurement of existing stands should provide some insight into their relative effectiveness in this regard.  As second-growth stands  develop, specific forest management prescriptions, including the use of thinnings and fertilization, can be employed to manipulate stand structure.  Use of these silvicultural techniques should allow the manager to  produce the desired canopy structure for effective interception of snow as well as to permit the development of forage plants in the understory. With harvest rotations of 100 years or less, i t is unlikely that s i g n i f i cant biomass of lichens w i l l develop in second-growth forests.  The current study suggests lichens are a food resource which deer exploit during most winters and which might provide sufficient energy to sustain animals during short periods of severe snow conditions.  Since maximum  measured levels of lichen production in l i t t e r f a l l were only 0.91 kg • ha  1  • day  1  and adult black-tailed deer (45 kg) require 1.3 kg air dry  forage per day for maintenance (Brown 1961), i t is clear that lichen production, as measured in this study could sustain only low numbers of deer for an extended period. As the area of mature forest is further reduced, higher winter densities of deer would be expected in the suitable stands remaining and lichens and other forms of l i t t e r f a l l w i l l be even less effective in maintaining deer through c r i t i c a l periods.  Severe winter conditions do not occur regularly, nor are they predictable.  In light of this uncertainty, the options of the wildlife manager  are limited although several exist.  One approach is to manage for high  274  levels of deer harvest each year, thus reducing the impact on the population of a severe winter k i l l one in 5 or 10 years. The alternative is a lighter level of harvest, accepting significant winter k i l l s at 5- to 10-year intervals. climatic  A third alternative is to manage according to past  patterns, with  harvest  levels  based  on anticipated  severe  winters.  With continued harvest of remaining mid- and low-elevation old-growth forest, deer population declines in the study area appear certain. The degree of decline will depend on the severity of winter, the amount of remaining c r i t i c a l winter range available and the rate at which secondgrowth forests develop and function as winter range.  With regard to the  latter, several areas of research beneficial to deer management are suggested: i n i t i a l l y  i t seems desirable to determine the stand structure  required to reduce snow depths substantially and allow development of an understory forage-producing layer.  As a baseline against which to assess  effectiveness of second-growth forest, retention of some area of mature forest winter range in several forest types seems desirable.  Forest fertilization appears  to have the potential to influence nega-  tively or positively the amount of understory vegetation present, depending  on the timing of application relative to tree size and density. The  degree to which fertilization can be used in combination with thinning to manipulate understory forage production warrants investigation.  Vancouver Island contains watersheds in varied stages of forest development ranging from a l l second-growth forest to a l l mature forest, although  275  limited numbers of the latter remain. This range of conditions presents an opportunity to examine the response of deer to conversion to secondgrowth forest.  Determination of habitat selection patterns of deer in  second-growth relative to winter weather conditions should aid in predicting the response  of deer and suggest management opportunities for  less-developed watersheds.  The apparent enhancement of digestibility of other plants by the presence of Alectoria sarmentosa suggests a nutritional importance that should be investigated  further.  Likewise, the nutritional mechanisms by which  deer utilize forage mixtures need better definition as the basis for understanding nutrition in wild deer.  This study has shown that black-tailed deer are opportunistic feeders, capable of selecting the most nutritious forages available but also able to withstand periods of limited availability of high quality forage. A wide variety of preferred forage species are characteristically present in large quantities in the serai stages following harvest of old-growth; the management challenge is one provide the reduced  of managing second-growth stands to  snow depths and forage necessary to deer survival  during severe winters.  2 76  LITERATURE CITED Belovsky, G.E. 1978. Diet optimization in a generalist herbivore: the moose. Theor. Pop. Biol. 14:105-134. Bloom, A.M. 1978. Sitka black-tailed deer winter range in the Kadashan Bay area, Southeast Alaska. J. Wildl. Manage. 42:108-112. Brown, E.R. 1961. The black-tailed deer of western Washington. Washington State Game Dep. Biol. Bull. No. 13. 124 pp. Charnov, E.L. 1976. Optimal foraging: the marginal value theorem. Theor. Population Biol. 9:129-136. Harestad, A.S. 1979. Seasonal movement of black-tailed deer on northern Vancouver Island. Ph.D. Thesis, Fac. Forest. Univ. Brit. Columbia. 184 pp. Jones, G.W. 1975. Aspects of the winter ecology of black-tailed deer (Qdocoileus hemionus columbianus [Richardson]) on northern Vancouver Island. M.S. Thesis, Fac. Forest., Univ. Brit. Columbia. 75 pp. Jordan, P.A., D.B. Botkin, A. Dominski, H. Lowendorf, and G.E. Belovsky. 1973. Sodium as a c r i t i c a l nutrient for the moose of Isle Royale. N. Amer. Moose Workshop, 13-42. Krebs, J.R. 1978. Optimal foraging: decision rules for predators. pp. 23-63 In: Krebs, J.R. and N.B. Davies. Behavioural ecology an evolutionary approach. Blackwell Sci. Publ., Oxford. MacArthur, R. and E. Pianka. 1966. On optimal use of a patchy environment. Amer. Natur. 100:603-609. Pulliam, H.R. 1975. Diet optimization with nutrient contraints. Natur. 109:765-768.  Amer.  Pyke, G.H., H.R. Pulliam, and E.L. Charnov. 1977. Optimal foraging: a selective review of theory and tests. Quart. Rev. Biol. 52:137-154. Schoener, T.W. 1971. Theory of feeding strategies. Syst. 369-403.  Ann. Rev. Ecol.  Appendix T a b l e 1.  S e a s o n a l f r e q u e n c y and volume of o c c u r r e n c e and importance v a l u e of f o r a g e types consumed by b l a c k - t a i l e d deer c o l l e c t e d i n f o r e s t e d and c u t o v e r a r e a s . 1  Spring (13)  —•  2  —  Summer (18) 3  ImporImpor- tance Fretance V a l u e quency Value (%) (%)  ImporFreImpor- tance tance Value quency Value (%) (%)  F a l l - W i n t e r (39)  Volume— (m 1) (%)  ImporImpor- tance tance V a l u e Value (%)  20 .0 . 16. 2  15. 6  35.8  • 4.8  11.1  Forage Type  Frequency (%)  —Vo lume— (ml) (%)  Shrubs  100.0  61.8  47. 6  47.6  51.2  83.0  30.3  10.9  9.05  18.7  96.4  63.5  2.8  2. 2  1.4  1.5  22.0  14.5  5.2  1.14  2.4  90.2  6 .5  5. 3  -  -  . -  -  -  6.0  1.5  0.5  0.03  0.06  3.5  1 .2  1. 0  0. OA  tr."  -  -  -  28.0  4.1  1.5  0.42  0.9  .69.7  14 . 5  11. 8  8. 2  18.8  38.9  41.9  83.0  117.8  42.2  35.03  72.4  47.5  20 .4  16. 5  7. 8  17.9  0.08  0.2  51.9  5 .5  4. 5  2. 3  5.3  '-  66.8  tr.  Conifers Deciduous trees Lichens  34.0  —Volume— (ml) (%)  .  0.1  Forbs  100.0  50. 5  38. 9  Ferns  68.0  5.3  4. 1  2.8  3.0  11.0  2.0  0.7  Liverwort/ Moss  82.0  2.1  1. 6  1.3  3.0  28.0  tr.  -  Grass/ Sedge  13.5  6.9  5. 3  0.7  0.8  17.0  tr.  -  -  -  7.2  22 .7  18. 4  1. 3  3.0  -  -  -  -  11.0  5.0  1.8  0.20  0.4  18.0  9 .3  7. 5  1. 4  3.2  -  -  -  -  -  8.0  . 1.5  1. 2  • 0.1  0.2  2.13  4.4  Fungi Twigs/Bark Berries Equisetum Other Total  3  -  -. - •'.  4.5  tr.  -  43.0  0.5  0. 4  129.9  - . 0.2  -  0.2  6.0  99.0  35.5  -  -  -  4.7  1.7  17.0  92.9  Importance v a l u e i s the product of p e r c e n t f r e q u e n c y t h e importance v a l u e o f i n d i v i d u a l types d i v i d e d Number of rumens a n a l y z e d . No rumen samples were c o l l e c t e d from f o r e s t e d a r e a s t r . = t r a c e - volume of f o r a g e type was a t o r below  11  278.9  0.29 48.37  -  -  13.5  17 .5  14. 2  1. 9  . 4.4  0.6  5.4  4 .3  ' 3.5  0. 2  0.5  123 .4  43. 6 .  of o c c u r r e n c e and p e r c e n t volume. P e r c e n t importance v a l u e i s by the sum of the importance v a l u e s f o r a l l types.. i n summer; thus summer data r e p r e s e n t v a l u e s f o r c u t o v e r a r e a s o n l y . 0.5 ml.  Appendix Table 2.  Seasonal frequency and volume of occurrence and importance v a l u e consumed by b l a c k - t a i l e d deer c o l l e c t e d i n forested areas.  Spring ( ? )  Summer (0)  2  Forage Type  Frequency (%)  —Volume— (ml) (%)  ImporImpor- tance Fretance Value quency Value (%) (%)  Shrubs  100.0  92.0  70.1  70.1  70.3  Conifers  100.0  5.5  4.2  4.2  4.2  -  -  -  -  50.0  tr.  -  -  Forbs  100.0  18.3  13.9  13.9  Ferns  100.0  10.5  8.0  Liverwort/ 100.0 Moss  4.0  Deciduous trees Lichens  3  —Volume— (ml) (%)  of forage types  1  F a l l - W i n t e r (11)  ImporImpor- tance Fretance Value quency Value (%) (%)  —Volume— (ml) (%)  ImporImpor- tance tance Value Value (%)  100.0  22.6  28.9  28.9  37.0  91.0  6.8  8.7  9.6  12.3  -  -  -  -  -  100.0  26.9  34.4  34.4  44.0  13.9  27.0  2.8  3.6  1.0  1.3  8.0  8.0  18.0  6.8  8.7  1.6  2.0  3.1  3.1  3.1  55.0  0.33  0.4  0.2  0.3  -  -  -  -  -  Grass/ Sedge  -  -  -  -  -  Fungi  -  -  -  -  -  18.0  9.5  12.1  2.2  2.8  Twigs/Bark  -  -  -  9.0  2.0  2.6  0.2  0.3  -  -  -  . -  Berries  -  -  -  -  -  -  -  Equisetuin  -  -  -  -  -  9.0  0.5  0.6  0.05  0.06  1.0  0.8  0.4  0.4  -  -  -  -  -  Other Total  3  50.0  131.3  99.7  78.23  78.15  Importance v a l u e i s the product of percent frequency of occurrence and percent volume. Percent importance value i s the importance v a l u e of i n d i v i d u a l types d i v i d e d by the sum of the importance values f o r a l l types. Number of rumens analyzed. t r . = t r a c e - volume of forage type was a t or below 0.5 ml.  Appendix Table 3.  Seasonal frequency and volume of occurrence and importance v a l u e consumed by b l a c k - t a i l e d deer c o l l e c t e d 'in-cutover areas.  Spring ( l l )  Forage Type jc  Shrubs Conifers Deciduous trees Lichens  Frequency (%)  —Volume—(ml) (%)  100.0  31.6  27.0  18.0  Forbs  100.0  Ferns  36.0  Liverwort/ Moss  64.0  Grass/ Sedge  27.0  24.8  Summer (18)  2  ImporFreImpor- tance tance Value quency Value (%) '(%) 24.8  —Volume-— (ml) (%)  ImporImpor- tance tance Value Value (%)  83.0  30.3  10.8  9.05  18.7  92.8  17.3  10. 2  9.5  21.6  22.0  14.5  5.2  1.14  2.4  89.3  6.3  3. 7  3.3  7.5  -  -  -  -  6.0  1.5  0.5  0.03  0.06  7.0  2.3  1. 4  0.1  0.2  tr.  -  -  -  28.0  4.1  1.5  0.42  0.9  39.3  2.1  1. 2  4.7  10.7  83.0  117.8  42.2  35.03  72.4  67.9  38.0  15.3  34.7  2.0  0.7  0.08  0.2  85.7  4.3  22. 5 2. 5  2.1  4.8  -  -  81.8 tr. 0.14 13.7  64.3  64.3  -  -  11.0  0.1  6.4  6.5  28.0  tr.  -  -  -  78.6  tr.  10.8"  2.9  2.9  17.0  tr.  -  -  -  14.3  45.4  26. 8  3.8  8.6  -  11.0  5.0  1.8  0.20  0.4  17.9  9.2  5..4  1.0  2.3  -  -  -  -  -  -  7.0  1.0  0..6  0.04  0.1  -  6.0  99.0  2.13  4.4  -  -  Twigs/Bark  -  -  -  Berries  -  -  -  -  9.0  tr.  -  -  36.0  tr.  -  -  127.24  65.3  -  -  Total  ImporFreImpor- tance tance Value quency Value (%) (%)  -  -  Other  F a l l - W i n t e r (28)  -  3  -  Equisetum  of forage typ  -  tr.  —  Fungi  25.2  —Volume— (ml) (%)  1  98.4  -  17.0  35.5  -  —  -  -  -  -  17.9  34.5  20.,4  3.7  8.4  4.7  1.7  0.29  0.6  10.7  8.7  5.,1  0.5  1.1  278.9  169.1  44.04  'importance v a l u e i s the product of percent frequency of occurrence and percent volume. Percent importance value i s the importance value of i n d i v i d u a l types d i v i d e d by the sum of the importance values f o r a l l types. Number of rumens analyzed. t r . = t r a c e - volume of forage type was at or below 0.5 ml.  2 3  Appendix Table 4.  Monthly frequency, volumes and importance v a l u e s of forage types consumed by b l a c k - t a i l e d deer i n forested and cutover areas. 1  January (3)  February (5)  2  Frequency (%) Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Grass/Sedge Fungi Twigs/Bark Berries Equisetum Other  100.0 100.0 33.0 67.0 100.0 67.0 33.0  ---  Volume (ml)  (%)  4.0 2.0  18.0 9.0 47.0 26.0 -  -  tr. 10.5 5.8 tr. tr. -  3  Total  100.0 100.0 13.0 50.0 63.0 75.0 75.0  12.5 --  25.0 12.5  18.0 9.0  21.1 10.5  100.0 100.0  13.0 3.8  40.0 11.7 24.6 9.2 12.3 2.1  -  -  -  Marcn  25.3 6.7 0.5 24.1 9.8 10.0 0.27  25.3 6.7 0.07 12.1 6.2 7.5 0.2 -  tr. 2.0 19.5  2.2 21.0  -  92.8  36.8 30.4  -  -  —-  -  60.0 40.0 40.0 60.0  -  — — — —  • -  -  Importance Value  Volume  -  8.0 3.0 4.0 0.67 -  —— — —  — — — — — —  40.0 11.7  —  14.8 3.7 4.9 1.3  Importance Value (%) 52.4 15.3 —  19.4 4.8 6.4 1.7  —  —  —  -  —  —  —  — —  76.4  32.5 .  {o)  23.5 6.25 0.5 22.4 9.1 9.3 0.25  -  -  85.5 '  -  Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Grass/Sedge Fungi Twigs/Bark Berries Equisetum Other  m  -  22.3  Total  (ml)  31.5 26.0 -  ---  -  Frequency (%)  -  -  -  Importance Value  Importance Value (%)  0.6 2.6 61.3  41.3 10.9 0.1 19.7 10.1 12.2 0.3 -  -  '— — 1.0 4.2  100.0 100.0  -  50.0 67.0 67.0 83.0 33.0 17.0 —  —  67.0 33.0  6.9 14.5  -  25.7 25.5 1.0 tr. 89.8 tr.  — — 42.3 3.25 208.95  3.3 6.9 12.3 12.2 0.5  -  43.0  3.3 6.9  -  6.2 8.2 3.4  -  5.9 12.3  —  11.0 14.6 6.0  —  14.2  25.3  13.5 0.5  24.0 0.9  — — —  20.2 1.6  -  56.2  Appendix Table 4.  Monthly frequency, volumes and importance values of forage types consumed by b l a c k - t a i l e d deer i n forested and cutover areas, continued. June (6)  May (7) Frequency (%) Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Grass/Sedge Fungi Twigs/Bark Berries Equisetum Other  100.0 57.0 . 14.0 100.0 71.0 100.0 29.0 17.0  Volume (ml) (%) 39.6 2.75 tr. 56.4 4.2 1.29 20.5 tr.  31.7 2.2 45.2 3.4 1.0 16.4 -  Total  -  20.0 80.0. 60.0 60.0 20.0 40.0  2.2 2.75 10.0 158.3 tr. tr. 99.0 3.0 275.25  37.1 1.5 52.9 2.8 1.2 4.4 -  --  -  (ml)  100.0 17.0 33.0 100.0 17.0 33.0 17.0 17.0 17.0  42.3 tr. tr. 90.3 tr. tr. tr. tr. tr.  Volume  0.8 1.0  -  3.6 57.5 36.0 1.1  (%) 31.9 68.1 -  --  -  55.2  0.9 0.7 1.3 83.3 13.0 0.7  100.0 9.0 9.0 18.0 82.0 9.0 18.0 -  39.6 12.5 1.5 1.25 107.8 tr. 5.0 167.65  31.9 •68.1 -  31.9 - . 68.1 -  -  -  100.0  _ AUgUoL Atimirj f"nn 0.5 0.4 0.7 46.0 7.2 0.4  Importance Value (%)  Importance Value  132.6  (J)  July 60.0 40.0  31.7 1.3 45.2 2.4 1.0 3.8 -  Frequency (%)  85.4  124.74  Total  Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Grass/Sedge Fungi Twigs/Bark Berries Equisetum Other  Importance Value  Importance Value (%)  23.6 7.5 0.9 0.7 64.3 3.0 -  23.6 0.7 0.1 0.1 52.7 0.5 77.7  30.4 0.9 0.1 0.1 67.8 0.6 -  Appendix Table 4.  Monthly frequency, volumes and importance v a l u e s of forage consumed by b l a c k - t a i l e d deer i n f o r e s t e d and cutover areas, October  September (2)  Frequency  (%) Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Grass/Sedge Fungi Twigs/Bark Berries Equisetum Other  Volume (ml)  (%)  (%)  Frequency (%)  12.0 40.0  8.0 26.7  4.0 13.4  5.1 17.0  50.0 75.0  100.0 100.0 50.0 100.0  4.0 81.8 4.0 tr.  2.7 54.6 2.7  2.7 54.6 1.4  3.4 69.3 1.8  75.0 100.0 50.0 75.0 25.0 50.0  1.0 116.9 tr. 0.17 2.0 23.0  8.0  5.3  2.7  3.4  -  November  (%)  Importance Value  Importance Value (%)  5.5 1.3  2.8 1.0  3.2 1.1  0.7 76.1 0.1. 1.3 15.0  0.5 76.1  0.6 86.2  -  —  0.08 0.3 7.5  0.1 0.3 8.5  -  -  88.28  153.57  78.8  149.8  -  c o n t i n u e d .  (4)  Volume (ml)  50.0 50.0  Total  Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Crass/Sedge Fungi Twigs/Bark Berries Equisetum Other  Importance Value  Importance Value  8.5 2.0  50.0  W s  1  V  December (4)  (9)  100.0 67.0 11.0 67.0 33.0 78.0 67.0  40 2 4 6 4 0 11 6 5 5 3 7 tr.  53.0 6.1 5.3 15.3 7.2 4.9  53.0 4.1 0. 10. 2. 3.  68.9 5.3 0.8 13.4 3.1 4.9  33.0  6.3  8.3  2.7  3.5  3.4 7.6  4.4 9.7  4.4 9.7  7.6 16.9  50.0 50.0 50.0 75.0  28.0 35.5 2.0 0.17  35.9 45.5 2.6 0.2  17.9 22.8 1.3 0.15  31.1 39.6 . 2.2 0.3  75.0  1.3  100.0 100.0  1.7  1.3  2.3  77.97 57.55 76.9 75.9 Total Percent importance, value i s 'importance v a l u e i s the product of percent frequency of occurrence and percent volume the importance values f o r a l l types the importance v a l u e of i n d i v i d u a l types d i v i d e d by the sum of Number of rumens analyzed - volume of forage type was a t or below 0.5 ml. t r . = trace 2  Appendix Table 5.  Seasonal frequency, volumes and importance values of the 15 forage species occurring in greatest volumes i n rumens of black-tailed deer from forested and cutover areas. 1  Spring (13)' Frequency (%) Gaultheria shallon Rubus spp. Vaccinium spp. Thuja plicata Alectoria sarmentosa Epi lobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Potentilla palustris Rosa spp. Lactuaa muralio Pteridium aqualinum Tsuga heterophylla Lysichitum amerioanwn Linnaea borealis Equisetum spp. Lobaria ovegana Abies amabilis Rubus berries Total  — Volume — (ml) (%)  Summer (18) 3  Importance Value  Importance Value  9.0 95.5 86.5 4.5 29.5  6.0 51.5 9.8 tr. tr.  3.2 27.1 5.2  0.3 25.9 4.5  0.6 49.5 8.6  66.0 70.5 34.0 13.5  37.8 11.5 4.0 6.8  19.9 6.0 2.1 3.6  13.1 4.2 0.7 0.5  25..0 8..0 1..3 1..0  4.5 4.5 14.0 25.0 50.0  33.5 16.7 3.4 6.5 2.7  17.6 8.8 1.8 3.4 1.4  0.8 0.4 0.3 0.9 0.7  1..5 0.,8 0.,6 1. 7 1. 3  Frequency  67.0 67.0 22.0 28.0  24.0 13.1 12.6 4.1  7.5 4.1 4.0 1.3  5.0 2.7 0.9 0.4  11.7 6.3 2.1 0.9  78.0 50.0 11.0  114.6 7.6 2.0  36.0 2.4 0.6  28.1 1.2 0.7  65.7 2.3 1.6  6.0  10.3  3.2  0.2  0.5  11.0  1.5  0.5  0.1  0.2  11.0 17.0 22.0  3.8 28.7 1.8  1.2 9.0 0.6  0.1 1.5 0.1  0.2 3.5 0.2  94^0  29.6  JL8  4.2  6.0 190.2  52.3  — Volume — (ml) (%)  Importance Value  Importance Value (%)  318.1  42.8  Fall-Winter (39) Frequency (%)  Importance Value  Volume (ml)  Importance Value  78 .5 23 .5 60 .0 76 .0 69 .5  21.5 4.0 1.5 4.4 13.2  13.5 2.V 0.9 2.8 8.3  10.6 0.7 0.5 2.1 5.8  34.3 2.3 1.6 6.9 19.0  17 .0 29 .0 50,.0 7,.0 11..5  42.0 3.7 3.3 22.7 15.3  26.5 2.3 2.1 14.3 9.6  4.5 0.7 1.0 . 1.0 1.1  14.8 2.3 3.3 3.3 3.6  32. 0  1.9  1.2  0.4  1.3  19. 5 9. 0 41. 0 15. 5  4.2 17.3 2.1 1.1  2.6 10.9 1.3 0.7  0.5 1.0 0.5 0.1  1.6 3.3 1.6 0.3  158.8  30.5  'importance value i s the product of percent frequency of occurrence and percent volume Percent importance value Is the importance value of individual types divided by the sum of the importance values for a l l types. Number of rumens analyzed. No rumen samples were collected from forested areas i n summer; thus summer values are for cutover areas only t r . = trace - volume of forage type was at or below 0.5 ml.  Appendix Table 6.  Seasonal frequency, volumes and importance values of forage species occurring i n greates volumes i n rumens of black-tailed deer in forested areas. 1  Summer  3  Spring ( 2 )'  Gaultheria shallon Rubus spp. Vaeeir.iwn. spp. Thuja plioata Alectoria sarmentosa Epilobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Ptevidiim aqualinum Tiarella trifoliata Tsuga heterophylla Liverwort ' Lobaria oregana Polystichwn munitum Total  Frequency  55.6 8.3  65.2 9.7  100.0 18.0 45.0 73.0 100.0  21.9 2.3 0.7 4.8 24.8  23.3 2.5 0.8 5.1 26.4  23.3 0.5 0.4 3.7 26.4  37.0 0.8 0.6 5.9 41.9  9.0 18.0 18.0  6.0 1.3 2.5  6.4 1.4 2.7  0.6 0.3 0.5  0.9 0.5 0.8  9.0  19.0  20.3  1.8  2.9  64.0  3.7  3.9  2.5  4.0  82.0 18.0  2.5 4.3  2.7 4.6  2.2 0.8  3.5 1.3*  — Volume — (ml) (%)  100.0 100.0  80.0 12.0  55.6 8.3  50.0  tr>  -  -  -•  50.0 50.0 50.0  8.0 3.5 8.0  5.6 2.4 5.6  2.8 1.2 2.8  3.3 1.4 3.3  13.0 10.0 5.5 A.O  144.0  9.0 6.9 3.8 2.8  4.5 3.5 3.8 2.8  5.3 4.1 4.5 3.3  85.3  importance value i s the product of percent frequency of occurrence and percent volume. types divided by the sum of the importance values for a l l types. Number of rumens analyzed. 'Samples were not taken from deer in forested areas i n summer, ''tr. = trace - volume of forage type was at or below 0.5 ml.  2  Importance Value  Importance Value  Frequency (%)  50.0 50.0 100.0 100.0  Fall-Winter (11)  (0)  Importance Value (%)  (%)  — Volume (ml) (%)  93.8  Importance Value  (%)  63.0  Percent importance value i s the importance value of individual  Appendix Table 7.  Seasonal frequency, volumes and importance values of forage species occurring i n greatest volumes i n rumens of black-tailed deer i n cutover areas. 1  Spring (11) Frequency (%) 18.0 Gaultheria shallon 91.0 Rubus spp. 73.0 Vaccinium spp. 9.0 Thuja plicata 9.0 Alectoria sarmentosa Epilobium 82.0 angustifolium 91.0 Cornus canadensis 18.0 .Blechnum spioant 27.0 Grass spp. Fungi 9.0 Potentilla palustris 9.0 Rosa spp. 28.0 Lactuoa muralis 9.0 Smilacina raoemosa Rubus berries Lysitchum americanum Tsuga heterophylla Linnaea borealis Equisetum spp. Tellemia grandiflora Total  — Volume (ml) (%) 12.0 22.9 7.6 tr. tr.  4.7 9.0 3.0  67.7 19.5 tr. 13.7  26.6 7.7 _ 5.4 _ 26.3 13.2 2.7 1.6  3  67.0 33.5 6.8 4.0  254.7  -  3  Importance Value (%)  Importance Value  Importance Value (%)  Frequency (%)  0.8 8.2 2.2 _ -  1. 7 17.8 4.8 -  _ 67.0 67.0 22.0 28.0  24.0 13.1 12 .6 4.1  _ 7.5 4.1 4.0 1.3  5.0 2.7 0.9 0.4  11.7 6.3 2.1 0.9  47.4 15.2 3.3 5.2 2.6 1.7 0.2  78.0 50.0 11.0 6.0  114.6 7.6 2.0 10.3  36.0 2.4 0.6 3.2  28.1 1.2 0.7 0.2  65, 2,  11.0  1.5  0.5  0.1  0.2  6.0 17.0 11.0 22.0  94.0 28.7 3.8 1.8  29.6 9.0 1.2 0.6  1.8 1.5 0.1 0.1  4.2 3.5 0.2 0.2  21.8 7.0 1.5 2.4 ' 1.2 0.8 0.1  46.0  — Volume — (ml) (%) _  318.1  •importance value i s the product of percent frequency of occurrence and percent volume. types divided by the sum of the importance values for a l l types. Number of rumens analyzed. t r . = trace - volume of forage type was at or below 0.5 ml.  2  Fall-Winter (28)  Summer (18)  :  Importance Value _  42.8  0.5  Frequency (%)  — Volume — (ml) (%)  Importance Value  Importance Value (%)  57.0 29.0 75.0 79.0 39.0  21.1 6.9 2.4 4.0 1.5  9.1 3.0 1.0 1.7 0.6  5.2 0.9 0.8 1.3 0.2  19.3 3.3 3.0 4.8 0.7  25.0 40.0 82.0 14.0 14.0  77.9 6.1 4.1 45.4 11.5  33.6 2.6 1.8 19.6 5.0  8.4 1.0 1.5 2.7 0.7  31.1 3.7 5.5 10.0 2.6  7.0  3.0  1.3  0.1  0.4  39.0 18.0 4.0  8.4 34.5 5.0  3.6 14.9 2.2  1.4 2.7 0.1  5.2 10.0 0.4  231 .8  27.0  ce value i s the importance value of individual Percent importance  Appendix Table 8. ppe  Monthly frequency, volumes and importance values of forage species occurring i n greatest volumes i n rumens of black-tailed deer in forested and cutover areas. 1  January (3) 2  Frequency (%) 67.0 Gaultheria sluxllon 67.0 Rubus spp. Vaeeinium spp. 100.0 Thuja plicata 33.0 Alectoria sarmentosa 33.0 Epilobium angus tifo Hum Cornus canadensis 33.0 Blechr.um spicant 100.0 Grass spp. 33.0 Fungi Linnaea borealis 67.0 Abies amabilis 67.0 Dryopteris austriaca 33.0 Berber-is nervosa 33.0 Pseudotsuga menziesii Lobaria oregana Tsuga heterophylla Total  20.0 5.5 tr. 0.5 3.0 1.0 2.0  Frequency  5.1 5.1 3.3  75.0 83.5 83.5 50.0  15.7  51.6  38.7  57.3  --  9.7 9.7 6.3 -  0.3 3.8 2.2  1.0 12.8 7.2  0.8 10.7 3.6  50.9 14.0 -  16.8 14.0  31. 8 26.5  58.5 50.0  3.2 2.0  10.5 6.6  6.1 3.3  1.3 7.6 2.5 5.1  0..9 5,.1 0,.8 1 .7  1..7 9..7 1 .5 3 .2  7.6 7.6 3.3 _  -  Importance Value  m  25.0  52.8  — Volume — (ml) (%)  0.5  1.6  Importance Value  0.4  Importance Value  Importanoe Value (%)  Frequency (%)  — Volume — (ml) (%)  1.2 15.9 5.3  91.5 41.5 66.5 100.0 66.5  19.0 4.0 2.8 2.5 20.7  26.9 5.7 4.0 3.5 29.4  24.6 2.4 2.7 3.5 19.6  37.1 3.6 4.1 5.3 29.5  9.0 4.9  50.0 50.0  4.7 4.5  6.7 6.4  3.4 3.2  5.1 4.8  0.6  25.0 25.0 8.5  3.6 1.8  5.1 2.6  1.3 2.2  2.0 3.3  1.3 1.6 4.0  1.8 2.3 5.7  0.7 0.8 2.0  1.1 1.2 3.0  (%)  cr. 16.,5 50..0 33,.5  39.3  Importance Value  Importance Value (%)  Volume (ml) (%) 3.0 3.0 1.3 tr." tr.  March (8)  February (5)  3  0. 3 1.9 0.,5 30..4  1..0 6,.3 1,.6  0. 2 3..2 0.. 5 67,.5  0. 3 4., 7 0,.7  41.5 50.0 50.0  70.5  66.4  ON 00  Appendix Table S.  Monthly frequency, volumes and importance values of forage species occurring in greatest volumes i n rumens of black-tailed deer i n foreeted and cutover areas, continued. 1  Frequency (%) 70.0 Gaultheria shallon 90.0 Rubus spp. 80.0 Vaooinium spp. 100.0 Thuja plicata Alectoria sarmentosa 70.0 Epilobium 30.0 angustifolium 70.0 Cornus canadensis 40.0 Blechnum spicant 20.0 Grass spp. Fungi Pseudotsuga-• 10.0 menziesii . 80.0 Equisetum spp. 80.0 Tsuga heterophylla 10.0 Abies amabilis Ptevidium aqualinium Tiarella trifoliata Rosa spp. Linnaea borealis Laatuca muralis Hieracium albiflorum Potentilla palustris Total  — Volume (%) (ml)  Importance Value  Importance Value  Frequency (%)  — Volume (ml) (%)  Importance Value  Importance. Value (%)  1.6 13.8 2.9  2.8 24.1 5.1  (%)  10. 0 90. 0 90. 0 10. 0 25. 0  0.8 44.7 8.6 -  0.5 30.5 5.9 -  0.1 27.5 5.3 -  0.2 44.9 8.6 -  17.0 100.0 67.0  22.5 31.9 10.0  17.0  tr.  -  -  -  65. 0 75..0 45.,0 20..0 •  36.7 10.4 4.0 10.3  25.0 7.1 2.7 7.0  16.3 5.3 1.2 1.4  26.6 8.6 2.0 2.3  83.0 83.0  69.6 21.6  30.0 9.3  24.9 7.7  43.5 13.5  _  1.9 4.4 3.4 11.5  1.0 1.1 0.9 1.2  1.6 1.8 1.5 2.0  2.6 2.2 1.1 4. 2 7.9  1.8 2.0 0.9 4.2 5.5  4.4 4.8 2.2 10.2 13..3  14.5 1.3 tr. 44.9  9..4 0..8  2.,8 0.,6  6..8 1..5  29,.2  5..8  14,.0  4.0 28.3 4.4 6.5  2 .6 18 .4 2 .9 4 .2  0 .3 14 .7 2 .3 0 .4  0 .7 35 .6 5 .6 1 .0  41.3  Importance Value  Importance Value (%)  Frequency (%)  4.0 3.4 1.7 6.4 34.5  153.9  June (6)  May (7)  A p r i l (6)  _  50 .0 25 .0 25 .0 10 .0  — Volume — (ml) (%)  2.8 6.5 5.0 16.8  146.6  —  61.3  —  9.7 13.8 4.3  17.0  33.,0 33..0 33..0 17..0  0.8 6.8 1.8 67.0 232.0  0.3 2.9 0.8 28.9  0.1 1.0 0.3 4.9  0.2 1.7 0.5 8.6  57.2 l-o 00 —I  Appendix Table 8.  Monthly frequency, volumes and importance values of forage species occurring i n greatest volumes in rumens of black-tailed deer i n forested and cutover areas, continued. 1  July (5) Frequency (%) Gaultheria shallon Rubus spp. Vaccinium spp. Thuja plioata Alectoria sarmentosa Epilobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Gaultheria berries Linnaea borealis Tsuga heterophylla Lysitchum americanum Cornus stolonifera Araentlobium spp. Total  — Volume — (ml) (%)  Importance Value  Importance Value (%)  Frequency (%)  — Volume — (ml) (%)  6. 2 3.,1 15.,4 3.,1  3..1 1,.6 15,.4 3,.1  3.4 1.8 16.9 3.4  100.0 100.0 50.0 -  79.5 2.3 4.0  61.,2 1..8 3..1  61 .2 1 .8 1 .6  67.3 2.0 1.8  50.0  _8.0  6 .2  3 .1  3.4  10.0 0.3 2.5 28.7 5.5  0.1 11.4 13.1 2.5  142.0 14.1  76.8 7.6  61.4 6.1  86.5 8.6 -  tr. 5.0 6.0 5.0  0.5 0.6 0.5  --  20.0 20.0 20.0  2.7 3.2 2.7  109.5 2.3 tr.  60.0  73.0 27 .0 9.0 9.0  71.0  8.0 4.0 20.0 4.0  67.0 0.6  80.0 80.0  184.9  7 50.0 50.0 100.0 100.0  36.3 0.3 0.4  34.3 15.3 10.0 1.3  27.0 9.0 27.0 9.0  — Volume — (ml) (%)  49.8 i.o 4.6  73.0 9.0 9.0 18.0  0.7 0.8 0.7  Frequency (%)  21.0 1.1 0.7 0.2  0.8 0.1 0.1 1.5  -  219.7  0.03 1.0 3.5 0.2 54.2  Importance Value (%)  Importance Value (%)  —  0.6 0.1 0.1 1.1  _  Importance Value  11.4 0.6 0.4 0.1  1.0 0.3 0.3 5.4  _  2  —  1.8 0.5 0.5 10.0  _  September (2) --  :  15.67.0 4.6 0.6  60.0 20.0 20.0 20.0  -  -  August (11)  2  -  0.7 1.8 6.5 0.4  Importance Value  —  -  129.8  90 .9  ro oo oo  Appendix Table 8.  Monthly frequency, volumes and importance values of forage species occurring in greatest volumes in rumens of black-tailed deer in forested and cutover areas, continued. 1  November (9)  October (4) 2  Frequency  <Z) 50.0 Gaultheria shallon Rubus spp. Vaccinium spp. 50.0 Thuja plicata 75.0 Alectoria sarmentosa 75.0 Epi lobium angustifolium 100.0 Cornus canadensis 50.0 Blechnum spicant 50.0 Grass spp. 25.0 Fungi 50.0 Liverwort sporophyte 25.0 Linnaea borealis 25.0 Tsuga heterophylla 25.0 Tellemia grandiflora 25.0 Lobaria oregana Polystichum muni turn Rosa spp. Total.  — Volume — (ml) «) 0.8 7.8 1.0 1.0 114.5 1.5 tr. 2.0 23.0 0.5 1.5 3.0 5.0  161.6  Importance Value  Importance Value (%)  0.5  0.3  0.4  4.8 0.6 0.6  2.4 0.5 0.5  2.8 0.6 0.6  70.8 0.9  70.8 0.5  83.5 0.6  1.2 14.2 0.3 0.9 1.9 3.1  0.3 7.1 0.1 0.2 0.5 1.6  0.4 8.4 0.1 0.2 0.6 1.9  -.  -  -  84.8  -  -  Frequency (%)  — Volume — (ml) (Z)  Importance Val ue  Importance Value ("/)  66.5  5.0  -3.2  50.0 33.5 66.5  tr. 5.0 26.0  16.5 33.5 -  1.5 1.0 -  48.3 7.3 tr. 3.3 9.0  51.4 7.8 3.5 9.6  41.1 1.6 1.9 6.7  11.2  22.5 10.0 65.0 32.5 25.0 25.0 35.0 -  3.0 ' 4.5 2.7  3.2 4.8 2.9  0.7 0.5 1.9  1.2 0.8 3.2  -  —  —  3.3 0.7 0.2 1.1  5.5 1.2  -  -  2.7 0.8 2.9 94.0  10.1 -  -  2.9  -0.9 3.1 -  -  59.7  — Volume — (ml) <W  68.8 2.7  80.0 20.0 42.5 55.0 70.0  -9.5  Frequency (Z)  -0.3 1.8 -  -  37 .5 33.5 66.5 66.5 16.5  -  -  tr. 17.0 3.0 —  2.0 0.7 61.2  Importance Value  8.2 8.2 42.5  28.3  2.5 1.6 -  0.4 0.5 -  -  27.8 4.9 ~  3.3  -  1.1  5.5  6.9  -  Impcr. tance Value <*>  9.7 — —  12.2 50.0 0.7 0.9  --  —  —  9.3 3.3  16.4 5.8  —  2.2  -  0.2  —  3.9  -  0.4  56.6  'importance value Is the product of percent frequency of occurrence and percent volume. Percent Importance value i s the importance value of individual types divided by the sum of the importance values for a l l types. Samples were not taken from deer in forested areas In these months; data are for deer from cutover areas only. Number of rumens analyzed. tr. = trace - volume of forage type was at or below 0.5 ml.  2  3  11  oo vo  Appendix Table  9. Monthly frequency, volumes and importance values of forage species occurring i n greatest volumes i n rumens of black-tailed deer in forested areas. 1  Gaultheria shallon Rubus spp. Vaooinium spp. Thuja plicata Alectoria sarmentos Epi lobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Pseudotsuga menziesii Lobaria oregana Tsuga heterophylla Berberis nervosa Equisetum spp. Total  Importance Value  Importance Value (%)  47.8  53. 2  Frequency (%)  — Volume — (ml) (%)  100.0  16.3  67.0 67.0 100.0  0.5 7.5 4.3  1.5 22.0 12.6  1.0 14.7 12.6  67.0  0.3  0.9  0.6  -  -  -  -  33.0 100.0 67.0  0.5 3.7 1.0  34.1  47.8 _  1.5 10.8 2.9  A p r i l (1)  March (2)  February (3)'  89.9  Frequency (%)  — Volume — (ml) (%)  Importance Value  Impor tanoe Value (%)  Frequency (»)  — Volume — (ml) (%)  1. 1 16..3 14. 0  100.0 50.0 50.0 100.0 100.0  13.0 0.5 2.0 2.3 41.5  17.8 0.7 2.7 3.1 56.8  17.8 0.4 1.4 3.1 56.8  19..5 0..4 1 .5 3 .4 62 .1  100.0 100.0 100.0 100.0 100.0  0.5 4.0 0.5 4.0 65.0  0.6 5.1 0.6 5.1 82.3  0. 6 5. 1 0. 6 5..1 82. 3  0.6 5.1 0.6 5.1 82.3  0..7  50.0  2.0  2.7  1.4  1 .5  100.0  0.5  0.6  0.,6  0.6  50.0  tr.  -  -  -  -  -  50.0 100.0 50.0 50.0  0.5 3.3 7.5 0.5  100.0  4.0  5.1  5 .1  5.1  100.0  0.5  0.6  0,.6  0.6  _  0.5 10.8 1.9  Importance Value  Importance Value (%)  0 .6 12 .0 2..1  73.1  0.7 4.5 10.3 0.7  0.4 4.5 5.2 0.4  91.4  0 .4 4 .9 5 .7 0 .4  79.0  100 .0  to vO  o  Appendix Table  9. Monthly frequency, volumes and importance values of forage species occurring i n greatest volumes i n rumens of black-tailed deer i n forested areas, continued. 1  Frequency Gaultheria shallon 100.0 Rubus spp. Vaccinium spp. 100.0 _ Thuja plioata Alectoria sarmentosa 50.0 Epi lobium angus tifo Hum 50.0 Cornus canadensis 50.0 Blechnum spicant 50.0 Grass spp. Fungi Liverwort sporophyte 100.0 Tsuga heterophylla 100.0 50.0 Pteridium aqualinum Tiarella trifoliata 50.0 Maianthemum dilatation 50.0 Lysitchum amerioanum 50.0 Lobaria oregana Polystichum muni turn Abies amabilis Total  Volume —  Importance Value  Importance Value  50.3 7.5 -  50.,3 7.5  61..4 9.2  8.0 3.5 8.0 4.0 5.5 13.0 10.0  5.0 2.2 5.0 2.5 3.5 8.2 6.3  2..5 1.,1 2.,5  3.,0 1..3 3..0  2..5 3..5 4,.1 3,,2  3..0 4..3 5,.0 3,.9  7.0 8.0  4.4 5.0  2,.2 2..5  2 .7 3,.0  80.0 12.0 _  tr.  159.0  81 .9  Frequency  Volume — (ml) (%)  3  Importance Value  Importance Value (%)  Impor tance Value (%)  4..7  4..7  4..7  100. 0 100. 0  5.,0 52.,0  7.,8 81..3  7..8 81..3  7.8 81..3  3.8  100..0  2,.0  3,.1  3 .1  3,.1  1.0 3.1 1.0  100 .0  2 .0  3 .1  3 .1  3..1  40.3 5.0 14.9  40.3 2.5 14.9  56.4 3.5 20.8  25.0 50.0 25.0  6.0 2.5 19.0  6.0 2.5 18.9  1.5 1.3 4.7  2.1 1.8 6.6  50.0  5.3  5.3  2.7  50.0 50.0 25.0  1.5 4.3 1.5  1.5 4.3 1.5  0.7 2.2 0.7 71.5  — Volume — (ml) (7.)  Importance Value  3..0  40.5 tr. 5.0 15.0  100.6  Frequency (%) 100..0  100.0 25.0 50.0 100.0  'importance value i s the product of percent frequency of occurrence and percent volume. types divided by the sum of the importance values for a l l types. Number of rumens analyzed. t r . = trace - volume of forage type was at or below 0.5 ml  2  December (1)  November (4)  May (2)  64 .0  100 .0  Percent importance value i s the importance value of individual  Monthly frequency, volumes and importance values of forage species occurring in greatest volumes in rumens of black-tailed deer in cutover areas.  Appendix Table 10.  Frequency (%) 67.0 Gaultheria nliallon Rubus spp. 100.0 Vaooinium spp. 33.0 Thuja plicata Alectoria sarmentosa 33.0 Epilobium angus tifo Hum 33.0 Cornus canadensis 100.0 Blechnum spicant 33.0 Grass spp. Fungi 67.0 Linnaea borealis Dryopteris austriaca: 33.0 67.0 Abies amabilis 33.0 Berberis nervosa Pseudotsuga menziesii Equisetum spp. Tsuga heterophylla Polystichum muni turn Total  — Volume (ml) (%)  Importance Value  Importance Value (%)  Frequency (%)  — Volume (ml) (%)  3.0  8. 3  5.6  9.4  50.0  15.0  1.3 tr. tr.  3.6  3.6 _  6.0 -  -  -  tr. tr.  -  100.0 100.0 -  58.1 15.2  18.2 15.2 --  30.4 25.4  50.0 100.0 -  6.0 4.0 -  0.9 8.9 5.6 1.8  1.5 14.9 9.4 3.0  3  20.0 5.5 tr. 0.5 1.0 3.0 2.0  36.3  -  1.42.7 8.3 5.5  March (6)  February (2)  January (3)'  _  59.8  -  _  50.0  _  Importance Value  Importance Value (%) 50.0  -  28.9 -  23.1 15.4  11.6 15.4  20.1 26.6  —  —  57.7 _  -  -  —  1.0  26.0  — 3.8  1.9  57.8  3.3  Importance Value  Importance Value (%)  33. 1 9.9 4.9 3.7  27.5 3.3 4.1 3.7  41.8 5.0 6.2 5.6  7.3 8.9  9.6 11. 7  4.8 11.7  7.3 17.8  50.0  7.2  9. 5  4.8  7.3  17.0  3.5  4..6  0.8  1.2  33.0 33.0 50.0 67.0  5.0 2.0 2.3 0.6  6..6 2.,6 3..0 0..8  2.2 0.9 1.5 0.5  3.3 1.4 2.3 0.8  Frequency (%)  — Volume (ml) (%)  83.0 33.0 83.0 100.0 33.0  25.1 7.5 3.7 2.8 tr.  50.0 100.0  75.9  65.8  Appendix Table 10.  Monthly frequency, volumes and importance values of forage species occurring i n greatest volumes i n rumens of black-tailed deer in cutover areas, continued. 1  Frequency (%) Gaultheria shallon Rubus spp. Vaccinium spp. Thuja plicata Alectoria sarmentosa Epilobium angusti folium Cornus canadensis Blechnum spicant Grass spp. Fungi Pseudotsuga. menziesii Equisetum spp. Lobaria oregana Tsuga heterophylla Abies amabilis Lysitchum americanum Lactuca muralis Smilacuma racemosa • Rosa spp. Linnaea borealis Hieracium albiflorum Potentilla palustris Total  — Volume — (ml) (%)  Importance Value  Importance Value (%)  31.4  20.0 60.0 40.0 60.0 20.0 40.0  8.0 56.2 2.0 4.7 13.0 3.0  3.4 24.0 0.9 2.0 5.6 1.3  0.7 14.4 0.4 1.2 1.1 0.5  1.,4 29.,4 0..8 2..4 2,.2 1,.0  49.0  163.6  22.5 31.9 10.0  1.6 13.7 2.9  2.8 24.0 5.l'  —  —  83.0 83.0  69.6 21.6  49.4 16.4  12.5  5.0  7.7  17.0  tr.  -  — —  4.3 2.4 20.5  0.9 4.8 4.1  1.4 7.4 6.3  33..0  6.8  2.,9  1.0  1.7  33,.0 33,.0 17 .0  0..8 1.,8 67..0  0..3 0..8 28..9  0.1 0.3 4.9  0.2 0.5 8.6  7.0 4.0 33.5  15.4  17.0 100.0 67.0 17.0  31.9 10.6  20.0 20.0 20.0  38.4  9.7 13.7 4.3  — Volume (ml) (%)  39.9 10.6  65.3 17.3 tr. 20.5  tr. 89.8  Importance Value (%)  -  80.0 100.0 40.0 40.0  12.4 0.9  Importance Value  -  15.1 0.8  29.0  Frequency (%)  0.3 7.1 3.9  0.9 5.7 3.1  60.0 40.0 80.0 40.0  Importance Value  Importance Value (%)  0.2 4.6 2.5 -  1.5 9.4 5.1 tr. -  3.2 1.2 1.2 3.8 1.7  233.8  — Volume (ml) (%)  20.0 80.0 80.0 20.0  7.5 2.9 2.8 8.8 4.0  7.4 0.4  Frequency (%)  2.7 2.0 1.4 7.7 1.4  40.0 80.0 60.0 100.0 40.0  2 Jo  June (6)  May (5)  A p r i l (5)  -  -  -  64.6  -  -  -  tr.  -  232,.0  ~ 30.0 9.3  24.9 7.7  43.6 13.5 -  —  57.1  t\3 VO  Appendix Table 10.  Monthly frequency, volumes and importance values of forage species occurring i n gr volumes i n rumens of black-tailed deer in cutover areas, continued. 1  Frequency (%) Gaultheria shallon Rubus spp. Vaooinium spp. Thuja plicata Alectoria sarmentosa Epilobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Gaultheria berries Linnaea borealis Rv.bus berries Tsuga heterophylla Lysitchum americanum Arcentlobium spp. Total  60.0 20.0 20.0 20.0  — Volume — (ml) (%) 1.8 0.5 0.5 10.0  80.0 80.0  142.3 14.1 .  60.0  tr.  20.0 20.0 20.0 20.0  5.0 6.0 94.0 5.0  279.2  Importance Value  Frequency (%)  —Volume — (ml) (%)  Importance Value  Importance Value (%)  Erequency  (%)  — Volume — (ml) (%)  Importance Value  Importance Value (%)  73.0 91.0 9.0 18.0  34.3 15.3 10.0 1.3  16.8 7.5 4.9 0.6  12.3 6.8 0.4 0.1  19.5 10.8 0.6 0.2  50. 0 50. 0 50. 0 100. 0  8.0 4.0 40.0 4.0  5.3 2.7 26.7 2.7  2. 1. 13. 2.  3. 1. 16. 3.  40.8 4.1 -  71.4 7.2 -  73.0 27.0 9.0  109.5 2.3 tr.  53.7 1.1  39.2 0.3 -  62.2 0.5 -  100..0 100..0 50..0  79 5 2 3 4.0  53.1 1.5 2.7  53.1 1.5 1.4  67.4 1.9 1.8  0.4 0.4 6.7 0.4  0.7 0.7 11.7 0.7  50 .0  8.0  5.3  2.7  3.4  3.6  51.0 5.1  1.8 2.1 33.7 1.8  Importance Value (%) 6.3 1.2  0.6 0.2 0.2 3.6  -  September (2)  August (11)  July (5)  _  0.7  57.1  -  9.0 27.0  —  2.5 28.7 203.9  -  1.2 14.1  : 0.1 3.8 63.0  0.2 6.0  149.8  78.8  4>  Appendix Table 1 0 .  Monthly frequency, volumes and importance values of forage species occurring i n greatest volumes i n rumens of black-tailed deer in cutover areas, continued. 1  Fre-  1  (%) 50.0 _ 50.0 75.0 75.0  Gaultheria shallon Rubus spp. Vaccinium spp. Thuja plicata Alectoria sarmentosa Epilobium angustifolium 100.0 Cornus canadensis 50.0 Blechnum spicant 50.0 Grass spp. 25.0 Fungi 50.0 25.0 Linnaea borealis Tsuga heterophylla 25.0 Tellemia grandiflora 25.0 Polystichum muni turn Lactuca muralis Rosa spp. Lobaria oregana Abies amabilis Total  J  Volume (ml) (%) 0.8 _ 7.8 1.0 1.0 114.5 1.5 tr. 2.0 23.0 1.5 3.0 5.0  161.1  0.5 _ 4.8 0.6 0.6 71.1 0.9 1.2 14.-3T 0.9 1.9 3.1  Importance Value  Importance Value (%)  Frequency (%)  — Volume (ml) (%)  3  Importance Value  Importance Value (%)  Frequency (%)  Volume — (ml) (%)  Importance Value  Importance Value (%) 6.2 1.9 17.1  0.3 _ 2.4 0.5 0.5  0.4 2.8 0.6 0.6  60.0 40.0 60.0 60.0 40.0  56.0 14.5 0.5 1.7 3.0  61.5 15.9 0.5 1.9 3.3  36.9 6.4 0.3 1.1 1.3  71.8 12.5 0.6 2.1 2.5  33.0 100.0 67.0 33.0  7.0 0.7 9.5 tr.  10.9 1.1 14.8 —  3.6 1.1 9.9  71.1 0.5 0.3 7.2 0.2 0.5 0.8  84.3 0.6 0.4 8.5 0.2 0.6 0.9  _ 20.0 80.0 40.0  _ 9.0 2.8 tr.  9.9 3.1 -  2.0 2.5 -  3.8 4.9 -  33.0 67.0 67.0 33.0  3.0 2.0 34.0 4.0  4.7 3.1 53.0 6.2  1.6 2.1 — 35.5 2.0  2.8 3.6 — 61.3 3.5  20.0 20.0 60.0  1.5 1.5 0.5  1.6 1.6 0.5  0.3 0.3 0.3  0.6 0.6 0.6  33.0 33.0 33.0  1.5 2.0 0.5  2.3 3.1 0.8  0.8 1.0 0.3  1.4 1.7 0.5  84.3  91.0  'importance value i s the product of percent frequency ol' occurrence and percent volume. types divided by the sum of the importance values for a l l types. Number of rumens analyzed. t r . = trace - volume of forage type was at or below 0.5 ml.  2  December (3)  November (5)  October (4)  51 .4  64 .2  —  —  57.9  Percent Importance value i s the importance value of individual  

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