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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 University, 1966 M.Sc, Washington State University, 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 this thesis as conforming to the required standard THE- UNIVERSITY. OF BRITISH COLUMBIA May, 1980 0 .-James Arthur Rochelle, 1980'-In presenting th is thesis in par t ia l fu l f i lment of the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the Library shal l make i t f ree ly ava i lab le for reference and study. I further agree that permission for extensive copying of th is thesis for scholar ly purposes may be granted by.the Head of my Department or by his representat ives. It is understood that copying or publ icat ion of th is thesis for f inanc ia l gain shal l not be allowed without my written permission. r Department nf V ^ f W r ^ The Univers i ty 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 relative availability and quantities of black-tailed deer (Odocoileus  hemionus columbianus [Richardson]) forage supplied by l i t t e r f a l l and understory vegetation during winter were assessed in selected mature conifer stands in the Nimpkish Valley of northern Vancouver Island. Composition and rates of l i t t e r f a l l 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 stands and logged areas. Monthly patterns of variation were determined over a 1-year period for a number of measures of forage quality including in vitro dry matter d i g e s t i b i l i t y (DDM), crude protein, c e l l contents, cellulose, hemicellulose and lignin. Analyses were made on ten forage species, known to be major dietary items of deer i n the study area. Nutrient characteristics were compared between plants growing beneath a mature forest canopy and in cutover areas. Rates of DDM for 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 volatile fatty acids (VFA) in products of in vitro fermentation were determined for the ten species examined. Patterns of monthly and seasonal variation in concentration, composition and caloric content were defined and contrasts were made between forested and cutover areas of collection. Characteristics of deer rumen contents including dry matter, crude protein and caloric content were determined monthly over a 1-year period, and related to deer food habits and nu-trient characteristics of forage species. Deer condition throughout the year and in relation to forage quality was assessed through determination of weight and amounts of fat deposited in selected tissues. Levels of i i i b lood urea n i t r o g e n (BUN) were determined r e l a t i v e to l e v e l s of p r o t e i n 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 s u i t a b l e as forage equal or exceed year-around q u a n t i t i e s of a v a i l a b l e rooted v e g e t a t i o n i n some mature c o n i f e r stands. Lichens made up 86 percent of forage l i t t e r f a l l . Monthly l i t t e r f a l l r ates v a r i e d i n response to weather c o n d i t i o n s . Deer consumed f a l l e n 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 provides a r e l a t i v e l y small but continuous source of forage during the wi n t e r . Forbs and shrubs were of major and equal importance i n the annual d i e t of deer. Epilobium a n g u s t i f o l i u m was the most h e a v i l y used species during the s p r i n g to f a l l p e r i o d ; use of c o n i f e r s and l i c h e n s was gre a t e s t i n wi n t e r . Reduced forage a v a i l a b i l i t y i n winter was r e f l e c t e d i n fewer species present i n rumen samples. Forage c h a r a c t e r i s t i c s v a r i e d d i s t i n c t l y i n response to p h e h o l o g i c a l changes i n the p l a n t . Lichens were the most d i g e s t i b l e forage but con-t a i n e d l e s s than 2 percent crude p r o t e i n . C o n i f e r s contained l e s s than the 7 percent p r o t e i n r e quired f o r maintenance during most of the year. C o n s i s t e n t l y higher n u t r i e n t l e v e l s i n p l a n t s from f o r e s t e d or cutover areas were not observed during any season of the year. D i g e s t i b i l i t y of forage mixtures was higher than 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 other components of mixed d i e t s . Most species were f u l l y digested w i t h i n 24 hours. Rumen f i l l , dry matter and crude p r o t e i n contents r e f l e c t e d forage q u a l i t y changes and deer food h a b i t s . i v Energy l e v e l s of forage 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 to pheno-l o g i c a l change; Epilobium a n g u s t i f o l i u m d i s p l a y e d the highest energy content of the species examined. Lichens and ferns were lowest i n energy content. Peak energy content i n most p l a n t s occurred i n summer. Ruminal VFA concentrations followed the seasonal p a t t e r n s observed i n forage p l a n t s ; peak concentrations occurred 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 winter. Maximum weights of deer occurred i n f a l l - e a r l y winter and minimums occurred i n l a t e w i nter. Greater weight gains occurred i n the l a t e summer-early f a l l p e r i o d when energy demands above maintenance were probably lowest. Mesentery weight and kidney f a t index appeared to be s u i t a b l e c o n d i t i o n i n d i c a t o r s . Blood urea n i t r o g e n was a good i n d i c a t o r of recent p r o t e i n i n t a k e . BUN l e v e l s d i d not increase during periods of weight l o s s , sug-g e s t i n g t i s s u e catabolism d i d not occur. V TABLE OF CONTENTS Page TITLE PAGE . . . . i ABSTRACT i i TABLE OF CONTENTS . . . . . . . . . . . v. LIST OF TABLES v i i i LIST OF FIGURES . x ACKNOWLEDGEMENTS . . . . . . . . . . . . x i i 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 . . . . 1 Introduction ^ Objectives 3 Study Location 3 Study Period • • Thesis Structure • 8 Literature Cited 9 CHAPTER II - LITTERFALL AND UNDERSTORY VEGETATION AS BLACK-TAILED DEER FORAGE IN MATURE CONIFER STANDS 10 Abstract 10 Rationale and Objectives 11 Literature Review 12 Methods . 20 Results and Discussion . . . . . . . . . . . . . . . 24 Characteristics of site/timber stands . . 24 Characteristics of understory vegetation .27 Amounts and nature of l i t t e r f a l l . . . . . . 32 Consumption of l i t t e r f a l l by deer 36 Relative A v a i l a b i l i t y of lichens and understory vegetation . . 38 Summary . . . . . . . 45 Literature Cited .47 CHAPTER III - FOOD HABITS OF BLACK-TAILED DEER, CHARACTERISTICS OF FORAGE PLANTS, AND RUMEN CHARACTERISTICS . . . . . 50 Abstract . . . . . . 50 Rationale and Objectives 51 Food habits 51 Characteristics of forage plants . . . . . . . 52 Rumen characteristics 53 v i Page Food Hab i t s o f B l a c k - T a i l e d Deer 53 L i t e r a t u r e rev iew . . . . . . . 53 Methods . . . . . . . . . . 55 Resu l ts and d i s c u s s i o n 57 Summary - Food h a b i t s o f b l a c k - t a i l e d deer . . . . . . . . 63 Forage C h a r a c t e r i s t i c s ' 66 L i t e r a t u r e review 66 Methods . . . . . . . . . . . . 77 Resu l t s and d i s c u s s i o n . . . . . . . . . . . . . . . . . . 84 Dry mat te r 84 Crude P r o t e i n . . . . . . . . . . 96 Dry mat te r d i g e s t i b i l i t y (DDM) 105 Rates o f d ry mat te r d i g e s t i b i l i t y . . . . . . . . . . 109 F i b r e components o f fo rage p l a n t s 112 NDF and c e l l contents 112 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 136 Hemice l lu lose . . . . 141 S o l u b i l i t y o f fo rage p l a n t s . . . . . . . . . . . . . 143 D i g e s t i b i l i t y (DDM) o f fo rage mix tu res . . . . . . . 145. Summary - d i g e s t i b i l i t y , 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 151 R e l a t i o n s h i p s between forage c h a r a c t e r i s t i c s . . . . . . . 156 Rumen C h a r a c t e r i s t i c s 168 L i t e r a t u r e review 168 Methods . . . . . 171 Resu l t s and d i s c u s s i o n 172 Dry mat te r con ten t 172 Rumen f i l l 176 Crude p r o t e i n con ten t 178 Summary - rumen c h a r a c t e r i s t i c s . . . . 180 Summary - Chapter I I I 180 Food h a b i t s . . . . . . 181 Forage c h a r a c t e r i s t i c s . 182 Rumen c h a r a c t e r i s t i c s . . . . . . . . . . . . . 184 L i t e r a t u r e C i ted 186 CHAPTER IV - SEASONAL VARIATION IN ENERGY VALUES AND THEIR RELATIONSHIP TO OTHER CHARACTERISTICS OF FORAGE PLANTS OF BLACK-TAILED DEER . . . . . . . . . . 193 A b s t r a c t 193 R a t i o n a l e and Ob jec t i ves 194 L i t e r a t u r e Review . 195 Methods 198 Resu l t s and D iscuss ion 201 . VFA p r o d u c t i o n and energy va lues o f forage p l a n t s . . . . 201 Composi t ion o f VFAs i n forage species 220 R e l a t i o n s h i p o f VFA composi t ion and energy v a l u e t o o ther 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 fo rage p l a n t s . . . 226 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 fo rage p l a n t s t o food h a b i t s o f deer 231 VFA c h a r a c t e r i s t i c s o f deer rumen contents 232 Summary - Energy Values and VFA Composi t ion o f Forage P l a n t s . 236 L i t e r a t u r e C i ted 239 v i i Page CHAPTER V - SEASONAL CHANGES IN CONDITION OF BLACK-TAILED DEER AND THEIR RELATIONSHIP TO PATTERNS OF FORAGE QUALITY . . 241 A b s t r a c t 241 R a t i o n a l e and Ob jec t i ves . . .. 242 L i t e r a t u r e Review 243 Methods 245 Resu l ts and D iscuss ion L i ve and f i e l d - d r e s s e d weights 248 Back f a t , mesentery f a t and k idney f a t index (KFI ) . . . . 253 B lood-urea n i t r o g e n (BUN) - . 257 Summary - Measures o f Body C o n d i t i o n and Blood Urea N i t r o g e n . 262 L i t e r a t u r e C i ted 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 . . . . . . 269 Summary and Management I m p l i c a t i o n s .269 L i t e r a t u r e C i t e d . 276 APPENDIX 277 vi i i L I S T O F T A B L E S P a g e C H A P T E R I I T a b l e 2 - 1 . A n n u a l l i t t e r p r o d u c t i o n i n c o n i f e r o u s f o r e s t s . . . 1 3 T a b l e 2 - 2 . D e s c r i p t i o n o f s t u d y s i t e s . 2 5 T a b l e 2 - 3 . C h a r a c t e r i s t i c s o f g r o u n d v e g e t a t i o n o n s t u d y s i t e s . . . 2 8 T a b l e 2 - 4 . 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 f o r a g e o n s t u d y s i t e s . . . 3 0 T a b l e 2 - 5 . C o m p o n e n t s o f l i t t e r f a l l s u i t a b l e a s d e e r f o r a g e . . . . . 3 3 T a b l e 2 - 6 . A l e c t o r i a s p p . l i t t e r f a l l a c c u m u l a t i o n o n f e n c e d a n d u n f e n c e d p l o t s d u r i n g t h e w i n t e r . . . . . . . . . 3 7 T a b l e 2 - 7 . H e i g h t s o f f o r a g e p l a n t s o n s t u d y s i t e s . . . . 3 9 C H A P T E R I I I T a b l e 3 - 1 . S e a s o n a l c o m p a r i s o n s o f 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 . . 8 5 T a b l e 3 - 2 . S e a s o n a l c o m p a r i s o n s o f 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 c o l l e c t e d f r o m f o r e s t e d a n d c u t o v e r a r e a s . . . . 8 8 T a b l e 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 a n d c u t o v e r a r e a s a t d i f f e r e n t s e a s o n s 9 2 T a b l e 3 - 4 . 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 n n u a l n u t r i e n t l e v e l s o f f o r a g e s p e c i e s . 9 7 T a b l e 3 - 5 . R a t e s o f i n v i t r o d i g e s t i b i l i t y o f s e l e c t e d f o r a g e s p e c i e s . 1 1 0 T a b l e 3 - 6 . S t a t i s t i c a l c o m p a r i s o n s o f c e l l c o n t e n t s a n d n e u t r a l -d e t e r g e n t f i b r e 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 a n d c u t o v e r a r e a s i n d i f f e r e n t s e a s o n s 1 1 3 T a b l e 3 - 7 . S e a s o n 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 , a n d 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 t y p e s 1 1 5 T a b l e 3 - 8 . S e a s o n a l c o m p a r i s o n s o f c e l l c o m p o n e n t s o f f o r a g e t y p e s c o l l e c t e d f r o m f o r e s t e d a n d c u t o v e r a r e a s . . . . 1 1 8 T a b l e 3 - 9 . S t a t i s t i c a l c o m p a r i s o n s o f c e l l c o m p o n e n t 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 a n d c u t o v e r a r e a s a t d i f f e r e n t s e a s o n s . 1 2 4 T a b l e 3 - 1 0 . 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 n n u a l f i b r e c o n t e n t s o f f o r a g e s p e c i e s 1 3 9 T a b l e 3 - 1 1 . D r y m a t t e r d i g e s t i b i l i t y o f f o r a g e m i x t u r e s 1 4 6 T a b l e 3 - 1 2 . D r y m a t t e r d i g e s t i b i l i t i e s o f f o r a g e m i x t u r e s c o n t a i n i n g i n c r e a s i n g p r o p o r t i o n s o f A l e c t o r i a s a r m e n t o s a 1 5 0 T a b l e 3 - 1 3 . S e a s o n a l n u t r i e n t c o m p o s i t i o n a n d c e l l c o m p o n e n t s o f p r i m a r y f o r a g e s c o n s u m e d b y b l a c k - t a i l e d d e e r c o m p a r e d t o m a j o r f o r a g e s a v a i l a b l e . . . 1 5 3 T a b l e 3 - 1 4 . 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 a n n u a l n u t r i e n t a n d f i b r e 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 1 5 7 T a b l e 3 - 1 5 . 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 a n n u a l n u t r i e n t a n d f i b r e 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 f r o m f o r e s t e d a n d c u t o v e r a r e a s 1 5 8 T a b l e 3 - 1 6 . 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 s e a s o n a l n u t r i e n t a n d f i b r e 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 . . . . . . . . . 1 5 9 T a b l e 3 - 1 7 . 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 a n d f i b r e c h a r a c t e r i s t i c s o f s h r u b s p e c i e s 1 6 0 i x P a g e T a b l e 3 - 1 8 . 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 a n d f i b r e c h a r a c t e r i s t i c s o f c o n i f e r s p e c i e s 1 6 1 T a b l e 3 - 1 9 . 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 a n d f i b r e c h a r a c t e r i s t i c s o f f o r b s a n d f e r n s 1 6 2 T a b l e 3 - 2 0 . R e g r e s s i o n s o f i n v i t r o d i g e s t i b i l i t y v a l u e s o n d r y m a t t e r , c r u d e p r o t e i n , c e l l c o n t e n t , a c i d - d e t e r g e n t f i b r e a n d a c i d - d e t e r g e n t l i g n i n . . . . 1 6 7 T a b l e 3 - 2 1 . S e a s o n a l l e v e l s o f r u m e n f i l l , d r y m a t t e r a n d c r u d e p r o t e i n c o n t e n t s o f r u m e n s o f b l a c k - t a i l e d d e e r c o l l e c t e d i n f o r e s t e d a n d c u t o v e r a r e a s . . . . . 1 7 3 T a b l e 3 - 2 2 . M o n t h l y l e v e l s o f r u m e n f i l l a n d d r y m a t t e r a n d c r u d e p r o t e i n i n r u m e n 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 . . . . . . . . . . . 1 7 4 C H A P T E R I V T a b l e 4 - 1 . S e a s o n a l a n d a n n u a l l e v e l s o f V F A p r o d u c t i o n a n d 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 t y p e s . . . . . . 2 0 3 T a b l e 4 - 2 . S e a s o n a l c o m p a r i s o n s o f V F A p r o d u c t i o n a n d a s s o c i a t e d c a l o r i c v a l u e s o f f o r a g e t y p e s c o l l e c t e d i n f o r e s t e d a n d c u t o v e r a r e a s 2 0 6 T a b l e 4 - 3 . S e a s o n a l a n d a n n u a l l e v e l s o f V F A p r o d u c t i o n a n d 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 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 a n d c u t o v e r a r e a s . 2 1 0 T a b l e 4 - 4 . S t a t i s t i c a l c o m p a r i s o n s o f c a l o r i c v a l u e s o f f e r m e n t a t i o n p r o d u c t s o f i n d i v i d u a l f o r a g e s p e c i e s . . 2 2 1 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 , V F A a n d 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 2 2 7 T a b l e 4 - 6 . 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 , V F A a n d 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 s p e c i e s 2 3 0 T a b l e 4 - 7 . S e a s o n a l c o m p a r i s o n s o f V F A c o n c e n t r a t i o n , c o m p o s i t i o n a n d e n e r g y v a l u e i n r u m e n 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 . . . . . 2 3 4 C H A P T E R V T a b l e 5 - 1 . S e a s o n a l p a t t e r n s i n s e l e c t e d m o r p h o l o g i c a l p a r a m e t e r s a n d m e a s u r e s o f b o d y c o n d i t i o n i n b l a c k - t a i l e d d e e r 2 4 9 T a b l e 5 - 2 . C o r r e l a t i o n s o f s e l e c t e d m o r p h o l o g i c a l p a r a m e t e r s a n d m e a s u r e s o f b o d y c o n d i t i o n i n b l a c k - t a i l e d d e e r . . 2 5 5 T a b l e 5 - 3 . S e a s o n a l l e v e l s o f b l o o d u r e a n i t r o g e n ( B U N ) a n d r u m i n a l c r u d e p r o t e i n i n b l a c k - t a i l e d d e e r 2 5 8 C H A P T E R V I T a b l e 6 - 1 . . S e a s o n a l c h a r a c t e r i s t i c s o f p r i m a r y f o r a g e s c o n s u m e d b y b l a c k - t a i l e d d e e r i n f o r e s t e d a n d c u t o v e r a r e a s . . . 2 7 1 L I S T O F F I G U R E S P a g e C H A P T E R I F i g u r e 1 - 1 . L o c a t i o n o f t h e N i m p k i s h V a l l e y s t u d y a r e a o n n o r t h e r n V a n c o u v e r I s l a n d 4 C H A P T E R I I F i g u r e 2 - 1 . A r r a n g e m e n t o f l i t t e r f a l l a n d r o o t e d f o r a g e c o l l e c t i o n p l o t s a t t h e s t u d y s i t e s . . . . . . . 2 1 F i g u r e 2 - 2 . S n o w d e p t h s r e l a t i v e t o p l a n t h e i g h t d u r i n g t h e w i n t e r o f 1 9 7 3 - 7 4 . 4 1 F i g u r e 2 - 3 . M o n t h l y f o r a g e l i t t e r f a l l r a t e s a n d s n o w d e p t h p a t t e r n s d u r i n g t h e s t u d y p e r i o d . . . . . . 4 3 C H A P T E R I I I F i g u r e 3 - 1 . S e a s o n a l p a t t e r n s o f u s e b y b l a c k - t a i l e d d e e r o f f o r a g e t y p e s 5 8 F i g u r e 3 - 2 . M o n t h l y p a t t e r n s o f u s e b y b l a c k - t a i l e d d e e r o f f o r a g e t y p e s 6 0 F i g u r e 3 - 3 . S e a s o n a l p a t t e r n s o f u s e b y b l a c k - t a i l e d d e e r o f f o r a g e s p e c i e s . . . . . . . . 6 2 F i g u r e 3-U. M o n t h l y p a t t e r n o f u s e b y b l a c k - t a i l e d d e e r o f f o r a g e s p e c i e s 6 4 F i g u r e 3 - 5 . A v e r a g e a n n u a l c o m p o s i t i o n o f f o r a g e t y p e s 9 8 F i g u r e 3 - 6 . M o n t h l y p a t t e r n s o f v a r i a t i o n i n c o m p o s i t i o n o f s h r u b s 1 0 2 F i g u r e 3 - 7 . M o n t h l y p a t t e r n s o f v a r i a t i o n i n c o m p o s i t i o n o f c o n i f e r s 1 0 3 F i g u r e 3 - 8 . M o n t h l y p a t t e r n s o f v a r i a t i o n i n c o m p o s i t i o n o f f e r n s , f o r b s a n d l i c h e n s 1 0 4 F i g u r e 3 - 9 . S o l u b i l i t y a n d d i g e s t i b i l i t y o f p l a n t d r y m a t t e r . . 1 4 4 F i g u r e 3 - 1 0 . M o n t h l y l e v e l s o f r u m e n f i l l a n d d r y m a t t e r a n d c r u d e p r o t e i n i n r u m e n 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 . 1 7 5 . x i P a g e C H A P T E R I V F i g u r e 4 - 1 . M o n t h l y 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 v a l u e o f f e r m e n t a t i o n p r o d u c t s o f s h r u b s p e c i e s . . . . 2 1 6 F i g u r e 4 - 2 . M o n t h l y 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 v a l u e o f f e r m e n t a t i o n p r o d u c t s o f c o n i f e r s p e c i e s . . . 2 1 7 F i g u r e 4 - 3 . M o n t h l y 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 v a l u e o f f e r m e n t a t i o n p r o d u c t s o f l i c h e n , f o r b a n d f e r n s p e c i e s 2 1 8 F i g u r e 4 - 4 . S e a s o n a l V F A c o m p o s i t i o n a n d c a l o r i c v a l u e s o f f e r m e n t a t i o n p r o d u c t s o f s h r u b s p e c i e s . . . . 2 2 2 F i g u r e 4 - 5 . S e a s o n a l V F A c o m p o s i t i o n a n d c a l o r i c v a l u e s o f f e r m e n t a t i o n p r o d u c t s o f c o n i f e r s p e c i e s . . . 2 2 3 F i g u r e 4 - 6 . S e a s o n a l V F A c o m p o s i t i o n a n d c a l o r i c v a l u e s o f f e r m e n t a t i o n p r o d u c t s o f l i c h e n , f o r b a n d f e r n s p e c i e s . . . . . . . . . . . . . . . . 2 2 4 . C H A P T E R V F i g u r e 5 - 1 . M o n t h l y p a t t e r n s o f v a r i a t i o n i n s e l e c t e d m o r p h o l o g i c a l p a r a m e t e r s a n d m e a s u r e s o f b o d y c o n d i t i o n i n b l a c k - t a i l e d d e e r 2 5 0 F i g u r e 5 - 2 . M o n t h l y l e v e l s o f b l o o d - u r e a n i t r o g e n a n d r u m i n a l c r u d e p r o t e i n i n b l a c k - t a i l e d d e e r . . . . 2 5 9 x i i ACKNOWLEDGEMENTS A number of organizations and individuals provided assistance at various points between i n i t i a t i o n and completion of the graduate program of which this thesis i s a part. 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. Dr. Fred L. Bunnell provided guidance and counsel throughout the e f f o r t , obtained f i n a n c i a l support as needed, and was p a r t i c u l a r l y helpful during thesis preparation. Graduate committee members Drs. J.P. Kimmins, D.M. Hebert, M.D. P i t t and R.M. Strang provided valuable input to the thesis i n the form of questions, advice and suggestions. The assistance of Dr. John Oh, who shared his expertise i n techniques of n u t r i t i o n a l evaluation and analysis, and interpretation of results i s appreciated. Fellow students G.M. Jones, R.D. E l l i s , A.S. Harestad and S.K. Stephenson helped i n interpretation of results by freely sharing th e i r data. The efforts of several f i e l d assistants, and p a r t i c u l a r l y those of W.G. Turnbull, are appreciated. The extra efforts of Joan Gelder i n preparation of the manuscript were essential to meeting the deadlines involved. My wife Barbara, and children Denise, Mike and J u l i e were capable f i e l d aides, and patient and constant supporters whose cheerful acceptance of other a c t i v i t i e s deferred was essential to the completion of t h i s e f f o r t . The leave-of-absence and f i n a n c i a l assistance provided by Weyerhaeuser Company i s gr a t e f u l l y acknowledged, as i s the several types of support pro-vided by the University of B r i t i s h Columbia and the B r i t i s h Columbia Fish and W i l d l i f e Branch. Canadian Forest Products Ltd. through Stan Chester, generously provided f a c i l i t i e s for 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 Early estimates indicated black - t a i l e d deer Odocoileus hemionus coluro-bianus populations (Richardson) were low i n mature conifer forests on the west coast of the United States and Canada. Population estimates ranged from 0.4 (Cowan 1945) to 6.0 deer per km2 (Brown 1961). Com-parable estimates made by these investigators for areas containing a mixture of old forests and regenerating cutover land were approximately 10 to 23 deer per km2. More recent population estimates i n unlogged areas of the east coast of Vancouver Island range from 13-38 deer per km2 (D. Hebert, pers. comm. 1979). In areas where logging has resulted i n removal of portions of mature conifer stands and where deep snows create severe winter conditions, deer require timber stands for winter cover (Cowan 1956, Edwards 1956, Jones 1975). Less snow accumulates beneath conifer stands than on cut-over areas, and deer movement i s less impeded i n such stands (Telfer 1970, Jones 1975). Also, microclimatic conditions are ameliorated i n timber stands, resulting i n more favorable situations for the conser-vation of energy (Moen 1968). Studies of food habits indicate that arboreal lichens and conifer foliage are important winter food items for b l a c k - t a i l e d deer (Cowan 1945, Gates 1968, Jones 1975). Arboreal lichens are available i n quantity only within mature conifer stands. 2 I t i s l i k e l y t h a t a l l o f t h e s e f a c t o r s o p e r a t i n g t o g e t h e r c o n t r i b u t e t o t h e s e l e c t i o n o f m a t u r e c o n i f e r s t a n d s a s w i n t e r i n g a r e a s b y d e e r . I n B r i t i s h C o l u m b i a , r e c o g n i t i o n o f t h e i m p o r t a n c e o f m a t u r e c o n i f e r s t a n d s t o w i n t e r i n g d e e r h a s r e s u l t e d i n m a n a g e m e n t r e c o m m e n d a t i o n s w h i c h p r o v i d e f o r t h e r e s e r v a t i o n o f s e l e c t e d s t a n d s f r o m h a r v e s t . S t r i p s o f m a t u r e t i m b e r e x t e n d i n g f r o m v a l l e y b o t t o m s t o 8 - 9 0 0 m e l e v a t i o n a r e a l s o b e i n g s e t a s i d e a s t r a v e l c o r r i d o r s f o r d e e r . T h e n e e d f o r t h e s e a c t i o n s i s c o n s i d e r e d d u r i n g t h e r e v i e w o f l o g g i n g p l a n s b y t h e F i s h a n d W i l d l i f e B r a n c h . I n f o r m a t i o n o n t h e v a r i a t i o n i n p o t e n t i a l p r o d u c t i o n o f f o r a g e , i t s a v a i l a b i l i t y a n d n u t r i e n t v a l u e w i l l a i d i n g u i d i n g f u t u r e s e l e c t i o n o f m a t u r e c o n i f e r s t a n d s f o r p r e s e r v a t i o n a s w i n t e r h a b i t a t f o r d e e r . A l t h o u g h s e v e r a l s t u d i e s h a v e b e e n m a d e o f t h e f o o d h a b i t s o f b l a c k -t a i l e d d e e r i n n o r t h w e s t e r n N o r t h A m e r i c a ( C o w a n 1 9 4 5 , B r o w n 1 9 6 1 , C r o u c h 1 9 6 4 , G a t e s 1 9 6 8 , J o n e s 1 9 7 5 ) l i m i t e d i n f o r m a t i o n i s a v a i l a b l e o n l e v e l s , a v a i l a b i l i t y a n d s e a s o n a l v a r i a t i o n o f n u t r i e n t s i n t h e m a j o r f o r a g e s p e c i e s . M a n y o f t h e s e p l a n t s a r e common t o t h e e n t i r e N o r t h w e s t a n d d a t a o f t h i s t y p e s h o u l d h a v e w i d e a p p l i c a t i o n . A n e x a m i n a t i o n o f t h e v a r i a t i o n i n p h y s i c a l c o n d i t i o n o f d e e r a s s o c i a t e d w i t h s e a s o n a l c h a n g e s i n f o r a g e q u a l i t y a l s o s h o u l d h a v e v a l u e i n i d e n t i -f y i n g m e a s u r e s o f f o r a g e q u a l i t y t h a t w i l d l i f e m a n a g e r s c o u l d u s e t o a s s e s s n u t r i t i o n a l s t a t u s o f d e e r r a n g e . 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 Farm License 39 of Canadian Forest Products, Limited. Specific research sites were located in the drainages of the Nimpkish River and two of its tributaries, the Woss and Davie Rivers. Figure 1. Location of the Nimpkish Valley study area on northern Vancouver Island. 5 The study area l i e s within the Coastal Western Hemlock Biogeoclimatic zone of Krajina (1965). Within t h i s zone s p e c i f i c study site s were located i n the western hemlock and salal-western hemlock association of the g l a c i a l d r i f t land type ( B e l l 1971). Tsuga heterophylla i s the climax overstory tree on these s i t e s . Pseudotsuga menziesii, Thuja  p l i c a t a , Abies amabilis, Tsuga mertensiana and Chamaecyparis nootkatensis may occur i n association with Tsuga heterophylla, the l a t t e r two species primarily at elevations above 700 m. Even-aged stands of Pseudotsuga  menziesii resulting from past w i l d f i r e s occurred i n large blocks at lower elevations i n the valley. 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. Site index (height of dominant trees at 100 years of age) for P. menziesii ranges from 24 to 60 m, with about 70 percent of the valley area having an average index of 42 m or higher (Bunce 1960). Willms (1971) described geologic history, physiography and logging patterns i n the valley as summarized below. The Nimpkish Valley was glaciated i n the Pleistocene, and therefore the s o i l s are deep only i n the va l l e y bottoms. Outcroppings of bedrock are common on the s i d e h i l l areas. Most of the valley area below 610 m i n elevation has been burned by w i l d f i r e within the past 1000 years. Logging i n parts of the val l e y began i n 1915; logging i n the study area i t s e l f began i n 1947 and con-tinues at present. The val l e y bottoms and some of the s i d e h i l l areas were progressively clearcut, but at present, most logging settings are separated by mature timber which i s l e f t unlogged for at least three years. The Nimpkish Valley i s mountainous, with many peaks higher than 1220 m. 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 fe 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 at Woss Camp vary from a maximum of 37°C to a minimum of -20°C. No month has an average temperature which is below freezing. 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 deter-minations were made in this lab concurrently with field work. Other analyses requiring more elaborate facilities were made in the labora-tories 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 deer, their habitat, and availability and nutrient characteristics of forage. To facilitate reading, and subsequent publication of some portions, the thesis is organized into chapters dealing with specific aspects 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 im-portant to survival of black-tailed deer in severe winters. The approach I followed was to first 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. Wash-ington State Game Dept. Biol. Bull. No. 13. 124 pp. 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 -terfall 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 re-mainder 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 under-story vegetation. In mid-elevation timber stands combined weights of l i t t e r f a l l 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 l i t t e r f a l l 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 critical 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 in recently logged areas, where greatest snow depths occur. Jones (1975) observed concentrations of deer in mature conifer stands during periods of deep snow. Litterfall may be a more important source of deer forage than understory vegetation during these periods of deep snow. Little information is available on the characteristics of l i t t e r f a l l 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 litter consumed by deer. 3) To quantify amounts of understory vegetation potentially avail-able 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 Litterfall, through the natural shedding of foliage, reproductive struc-tures, and other plant parts, as well as storm-caused breakage of epi-phytes, 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 al. (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 (1975) in second-growth P. menziesii. 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 litter of conifers was summarized by Bray and Gorham (1964) as ranging from distinctly seasonal to variable throughout the year. In old-growth P. menziesii, stands Abee and Lavender (1972) found that the vast majority of litter f e l l during the winter but that needle cast was 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 leaf l i t t e r f a l l was greatest in August and September. Moir (1972) observed that P. contorta shed needles continu-ously throughout the year. 13 Table 2-1. Annual l i t t e r production in coniferous f o r e s t s - metr ic tons • ha Moss and Twigs, Coniferous Stand Type Age ( v r s ) Coni fer N e e d l e s Hardwood Leaves Bark and Wood Reproductive S t r u c t u r e s Green Leaves Lichens Other Tota l Refer-ences Pseudotsuga menzies i i 45 - - - - - - - - 1.8 ( 1) Pseudotsuga menz ies i i 40 1.5 ( 5 2 ) a - - - • - 1.4(48) 2.9 ( 2) Pseudotsuga menz ies i i 33 2.2 (76) - - - - - 0.7(24) 2.9 ( 2) Pseudotsuga menzies i i mature 2.8 (47) 0.4 ( 6) 2.0(33) 0.7 (14) - - - 5.9 ( 3) Pseudotsuga menzies i i mature 1.9 (48) 0.5 (13) 0.6(16) 0.5 (13) 0.02(<1) - 0.4(10) 3.9 ( 4) Pseudotsuga menzies i i 350 - - - - - 2.0 ( 5) Thuja p l i c a t a not given - • - - - - - 2.2 ( 5) Abies amabil is not given - - - - - - - 1.8 ( 5) Tsuga heterophyl la not given - - - - - • - 1.1 ( 5 ) Picea s i t c h e n s i s / • Tsuga heterophvl la =150 "*" — - - - - 2.9 ( 6) Pinus contorta 78 3.2 (68) - 0.6(14) 0.8 (18) - - - 4.6 ( 7) Tsuga heterophvl la mature 0.17(15) 0.01 (1) 0.6(55) 0.16(15) 0.01(1) 0.08(7) 0.08(7) l . l b ( 8) Pseudotsuga 50-130 menzies i i/ Pinus engelmannii - - - - - 0 . 1 0 c • - - ( 9) Pinus contorta (cool temperate fo res ts ) a l l 2.5 ( 6 6 ) d — ( 1 6 ) d ( 9 ) d - ( 6 ) d 3.4 (10) a p e r c e n t - o f t o t a l l i t t e r f a l l . l i t t e r f a l l measurements made only during winter - tabular values represent a 180-day l i t t e r f a l l p e r i o d , only l i c h e n l i t t e r f a l l was measured. l i t t e r component f igures are approximate values as reported for 4 c o n i f e r l i t t e r f a l l s tud ies by Bray and Gorham (1964). e ( l ) Dimock, 1958; (2) W i l l , 1959; (3) Abee and Lavender, 1977; (4) C r i e r ( i n p r e s s ) ; (5) Tar rant , et a l . (1951); (6) Hurd, 1971; (7) Moir , 1972; (8) This study; (9) Edwards, et a l . (1960); (10) Bray and Gorham, 19657 14 A major influence in the timing of l i t t e r f a l l in temperate and boreal forests is the pattern of winter storms. Abee and Lavender (1972) attributed most of the total l i t t e r f a l l in winter to breakage under the weight of the snow. Will (1959) found f a l l of non-needle litter of P. menziesii was influenced by storms. Although Pike et al. (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. Lichens were made available to caribou (Rangifer articus) in British Columbia during winter both by fa 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. In Newfoundland arboreal lichens made up 54 percent of the winter 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 al. (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. Cliff (1939) reported the use of Alectoria fremontii by elk in winter in the Blue Mountains of Oregon. Kufeld (1973) sum-marized Cliff'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 its occurrence in the diet was much greater than its 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. In north central Washington, both white-tailed deer 0. virginianus and mule deer 0. hemionus make relatively heavy use of Alectoria spp. in winter (D. Pridmore, personal communication, 1975). Book et al. (1972) noted year-long use of several species of arboreal lichens by black-tailed deer in northwestern California. Greatest use occurred in 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 li 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 al. (1973) cite a number of studies in which moderate use of P. menziesii and other con-iferous 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 of coniferous foliage in rumen contents, primarily in winter. 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 al. (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 indi-cate that lichens and conifer foliage are important food items, particu-larly 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 litter which might serve as forage for ungulates was assessed only by Edwards et al. (I960). The components of litter 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 of l i t t e r f a l l that potentially would provide forage for ungulates. Studies treating ungulates have concentrated on estimating amounts of lichen present in the forest canopy and are discussed below. Edwards et al. (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 1. Depending on snow depth, which greatly influences height of caribou feeding in trees, available lichens ranged from 12 to 316 kg ha 1. Mortality and windfall of trees provided an estimated 82 kg ha 1 of lichens in a conifer stand supporting a total lichen load of 750 kg ha 1. Measurements of accumu-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""1 per year of lichen f e l l annually, based on summer measurements which probably under-estimate 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 1, respectively, of which 680 and 380 kg ha"1, respectively, were available to caribou. Based on calculations from the work of Edwards et al. (I960); Pike (1971) , and Pike et al. (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 old-growth 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 1 and estimated that about 90 kg ha 1 of this f e l l as litter, 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 in each of the elevation zones: (1) 150-450 m, (2) 450-760 m, and (3) 760-1070 m. High levels of snow f a l l in 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 in 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. At each plot center, a l l species of vegetation occurring on a 4-m2 circular plot were identified and their height class and canopy coverage recorded following the technique of Daubenmire (1959). 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 trap - lm^ Vegetation p l o t 16 25 14 12.5m 8 l 1 3 k—12.5m—1> 17 18 12 19 10 11 20 f4- 50m Figure 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 at the study s i t e s . 22 u t i l i z e d as forage by deer. These samples were placed i n p l a s t i c bags, taken to the laboratory and weighed and a composite sample of each species was oven dried. Following forage plant c o l l e c t i o n , each plot center was provided with 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 horizontal position by building up the low side with sections of logs and limbs available on the s i t e . A 10-plot sample was randomly chosen from the 25 plots for determination of monthly l i t t e r f a l l rates. A l l sites were v i s i t e d each month during the snow period and an additional l i t t e r trap was placed d i r e c t l y above the existing trap on these 10 plots. L i t t e r f a l l was measured for ap-proximately 6 months (October to A p r i l ) on site 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 collected as snow melted i n the spring and frozen for subsequent analyses. Analyses involved separation of accumulated l i t t e r on each trap into the following categories: Forage Items Non-forage Items Lichens Conifer needles Alectoria spp. 1  Lobaria oregana Bark Cones "Purple" lichen (Platismatia h e r r e i , P. lacunosa, Hypogymnion  enteromorpha) Moss Twigs Angiosperm leaves Branches Sphaerophorus globosus Wood aSince t h i s study Brodo (1977) has revised the taxonomy of Alectoria and a few samples are of the genus Bryoria. 23 Forage Items Non-forage Items Green Conifer Foliage Residue Tsuga heterophylla Other Thuja plicata Pseudotsuga menziesii Abies amabilis Individual litter components from each trap were placed in labelled paper-bags, 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 south-facing aspects; sites 1 and 3 were on west-northwest and west aspects, respectively. Table 2-2.Description of the study sites. Site Characteristic 1 Elevation (m) 343 Aspect WNW Slope % ' 25% Crown Closure (%) 95.0 9 -1 Basal area (mz*ha ) 66 Trees/hectare 531 x ht. sample trees (m) 35 Stand Composition (%)/ x diameter (cm) Pseudotsuga menziesii 2/130 Tsuga heterophylla 33/31 Thuja p l i o a t a 11/86 Abies amabilis 54/18 Gross Wood Volume (m3«ha -*-) Pseudotsuga menziesii 2.6 Tsuga heterophylla 4,6 Thuja p l i o a t a > 5.6 Abies amabilis 0.9 Total 13.7 Site Number JW Elevation Mid-elevation 3 4 2 5 282 435 732 610 W SE S S .17% 28% 65% 45% 96.0 98.0 94.0 94.0 101 96 80 74 479 1087 1294 857 38 36 18 21 17/79 6/97 7/58 10/69 78/28 . 85/15 58/28 69/28 5/81 9/74 35/18 22/36 0/0 0/0 >l/7 0/0 6.2 9.0 1.7 1.4 8.6 5.0 3.5 4.0 1.5 7.0 0.9 1.2 - - 0.6 16.3 21.0 6.7 6.6 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 neces-sarily 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 m2,ha 1, with a mean of 77 on mid-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 remnants of a stand which had developed following past disturbance. T. heterophylla was the most common understory species on four of the five sites and would li k e l y dominate the climax overstory. Gross wood volumes ranged from 660 m3*ha 1 on site 5 to 2100 m3*ha 1 on site 4. Mean volume for mid-elevation sites was 665 m3,ha 1 compared to a mean of 1700 m3,ha 1 on low-elevation sites. On the five sites combined, P. menziesii, T. heterophylla, T. plicata and A. amabilis contributed 33, 40, 25 and 2 percent, respectively, of the total wood volume. The study sites apparently were at the lower elevational limits of dis-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 sites. The mosses Stolcesiella  oreganum and Hylocomium splendens occurred at high frequencies and rela-tively high densities on a l l sites. Shrubs, which make up the bulk of rooted forage available, occurred at moderately high densities and fre-quencies only on mid-elevation sites. In mature timber stands in the same general area, Jones (1975) reported an increase in cover of Vaccinium spp. with increased elevation. 28 Table 2-3. C h a r a c t e r i s t i c s of ground vegetation on study s i t e s . Lou—elevation Sites Mid-elevation Sites (Site Number): 1 3 4 . . . - 2 — . . . 5 i F r e " b Fre- Fre- Fre- Fre-Coverage quency Coverage quency Coverage quency Covera ge quency Coverage quency TREE SEEDLINGS: Abies amabilis 1 8.0 - - - - - - - -Thuja p l i c a t a 1 4 .0 1 16.0 - - ] 4.0 Tsuga heterophylla 2 92.0 2 100.0 1 84.0 1 • 8.0 r 76.0 TREE STEMS: Abies amabilis 1 8.0 - - - - - - -Thuja p l i c a t a - - , 1 4.0 1 12.0 1 12.0 i 12.0 Tsuga heterophylla 1 4.0 1 36.0 1 44.0 1 4 .0 i 24.0 Pseudotsuga menziesii - - 1 4.0 - - 1 4 .0 i 8.0 SHRUBS: Gaultheria shallon - - 1 4.0 1 20.0 3 100.0 3 100.0 Vaccinium alaskaense 1 48.0 1 60.0 1 8.0 2 96.0 . 1 88.0 Vaccinium parvifolium 1 76.0 2 100.0 1 88.0 2 96.0 2 100.0 FORBS: Achlys t r i p h y l l a 1 4.0 - - 1 8.0 - - - -Chimaphila umbellata - - - - - - 1 36.0 1 4.0 Clintonia u n i f l o r a - - - - 1 4.0 - - - -Cornus canadensis 1 12.0 1 24.0 - - - ' - 1 . 8.0 Goodyera ob 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 borealis 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 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 T i a r e l l a t r i f o l i a t a - - - - 1 12.0 - - - -Viola sp. . - - 1 8.0 - - - • • • - - -FERNS: Blechnum spicant 1 16.0 - - - - - - - -Polystichum muniturn - - - - 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 3 100.0 Khytiadelphus loreus - - 2 88.0 2 96.0 - - 2 84.0 Rhytidiopsis robusta 1 16.0 1 20.0 1 36.0 1 40.0 2 96.0 OTHER: Down logs 1 16.0 2 64.0 2 64.0 1 4.0 1 28.0 Rotten wood 1 24.0 1 24.0 1 36.0 - -Exposed rock - - - - - - 1 4.0 "Coverage classes f r e q u e n c y = Frequency of occurrence = 11 Ptotal° Clots e d x 1 0 0 Class % Canopy Coverage 1 0-5 2 5-25 3 25-50 4 50-75 5 75-95 6 95-100 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 mid-and 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 varia-tion 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. The data indicate the standing crop of available 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. Quantities of available rooted forage on the study sites (current year's growth in kg.ha"1 dry weight). Site Number Low-elevation Mid-elevation Tree Seedlings Tsuga heterophylla 76.5 14.6 4.9 6.9 2.1 Thuja plioata - 0.1 0.02 6.4 Pseudotsuga menziesii - - - 5.8 -Shrubs Sum of tree seedlings 76.5 ± 21.47 14.7 ± 4.29 4.92 ± 1.15 19.1 ± 3.59 2.1 ± 1.88 ( ± S j ) Gaultheria shallon - 0.2 1.4 162.0 65.3 Vaeeinium alaskaense 2.6 6.7 0.1 24.8 5.8 Vaccinium parvifolium 4.7 9.0 1.0 15.9 7.3 Sum of shrubs (± s-) 7.3 ± 0.93 15.9 ± 1.37 2.5 ± 0.24 202.7 ± 12.18 78.4 + 4.20 Forbs Chimaphila umbellate. - - - 3.0 0.1 Cormus canadensis - 0.6 -Aohlys triphylla 0.1 Ferns Blechnum spiaant 2.6 - - - -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"1 by Gates (1968), and 290 kg-ha"1 by Crouch (1964) in 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 in some timbered areas are not greatly dif-ferent from quantities in cutovers. As will be discussed later in this chapter, the greater snow depths which occur in cutovers compared to timbered areas may act to further reduce this difference. AMOUNTS AND NATURE OF FORAGE LITTERFALL Because litter traps were in place for varying lengths of time on differ-ent sites, litter weights are calculated on a daily basis. Oven-dry weights of l i t t e r f a l l ranged from 0.25 kg*ha l 4day 1 on site 4 to 1.0 kg'ha •'••day 1 on site 5 (Table 2-5). On mid-elevation sites an average of 0.93 kg'ha *'day 1 of forage litter f e l l compared to an average of 0.30 kg'ha •'••day 1 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 li t t e r f a l l . 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 low-elevation stands, respectively. These values exceed total amounts of Table 2-5. Components of l i t t e r f a l l suitable as deer forage (kg'ha" 1). Low elevation Mid-elevation ( S i t e ) : ( L i t t e r C o l l e c t i o n Period - days): 1 168 3 146 4 124 2 169 5 87 Total kg-' " i . d y " 1 Total kg- 1 , d y 1 Total kg-' - i . d y - i Total 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 0, .6 36.1 0, .4 Lobaria oregana 29.0 0. .17 26.6 0.20 3.9 .0. .03 2.1 0. .01 27.4 0. .3 P l a t i s m a t i a spp. Hypogymnion enteromorpha 7.1 0. .04 5.8 0.04 13.7 0. .11 14.9 0, .09 13.9 0. .2 Sphaeroghorus globosus 0.19 0. .01 2.4 0.02 0.5 0. .004 0.1 0. .0005 1.2 o. .01 Total Lichens 38.2 0. .23 45.5 0.33 27.9 0. .22 125.4 0. .74 78.6 0. .91 GREEN CONIFER FOLIAGE: Tsuga heterophylla 3.7 0. .02 6. .7 0, .05 1.7 0.01 15.4 0, .08 3, .8 0, .04 Thuja p l i c a t a 0.6 0. .004 0. .2 0. .01 1.1 0.01 4.5 0. .03 2. .5 0. .03 Pseudotsuga menziesii 0.03 0. .0001 11. .2 0. .08 0.3 0.002 1.1 0. .006 0. .4 0. .005 Abies amabilis 0.2 0. .001 - - -Total Conifer Foliage TOTAL Lichens and Conifers 4.5 0. .03 18. .1 0. .14 3.1 0.02 21.0 0. .12 6. .7 0. .08 42.7 0. .25 63. .6 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 al. (1960), who reported 82 kg'ha 1 of lichens made available through mor-tality and windfall of trees plus an additional 21 kg'ha 1 through the fa l l of individual lichens, for a total of 103 kg'ha 1. Schroeder (1974) made estimates of annual lichen l i t t e r f a l l in the range of 8 to 274 kg'ha 1. Denison (1972) estimated f a l l of Lobaria oregana in old-growth Douglas-fir stands at 90 kg'ha 1 annually. These values were determined in several different forest types. 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. Ahti and Hepburn (1967) reported that light is one of the most critical 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. At northern latitudes south aspects would receive greater total amounts of insolation than other aspects. The steep slope results in a greater proportion of the upper 35 tree crowns being exposed to full 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 in-fluencing 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 in amounts ranging from 0.02 kg-ha 1 ,day 1 on site 4 to 0.14 kg-ha 1-day 1 on site 3 (Table 5). 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 ob-servation 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 lit t e r " weights of 5 to 50 kg-ha **yr 1 in mature conifer stands in western Oregon (Table 1). 36 With regard to total biomass of foliage present, Turner and Cole (per-sonal communication, 1975) summarized the literature on P. menziesii stands and noted a mean needle biomass of about 10,000 kg'ha 1 in 28- to 75-year-old stands. Pike et al. (1972) estimated 5040 kg*ha 1 of foliage biomass in stands they studied. Values for the stands examined in the present study probably approximate these measures. In the absence of specific biomass measurements i t appears that minor amounts of green foliage, suitable as forage, reach the ground as litter. Assuming a foliage biomass of 7500 kg*ha 1, less than 15 kg, or 0.2 percent f e l l 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 pro-vide 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 litter consumed by deer, fences 1.8 m high constructed of poultry netting were erected around 10 of the 25 litter 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. Table 2-6 lists quantities of Alectoria spp. that accumulated on fenced and unfenced plots during the winter Table 2-6. Amounts of Alectovia spp. l i t t e r f a l l that accumulated on fenced and unfenced pl o t s during the winter (x ± s x g.m2) Site 1 Site 3 Fenced pl 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 plots at p < 0.05 38 collection period. Over winter, fenced plots on both sites accumulated about five times as much Alectoria spp. litter as unfenced plots. This difference, which was significant (p = < 0.05) only on site 3, suggested that deer are consuming substantial amounts of Alectoria litter. Steven-son (1978) also recorded significantly more Alectoria litter 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 is evident from rumen content analyses that at least the lichen compo-nent 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 in 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 in winter. Foliage of conifers also occurred in significant volumes in deer from mature forests but the source of this foliage could not be determined. Heavy feeding was observed on fallen green limbs, particu-larly 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 Table 2-7. Mean heights of a v a i l a b l e 3 f o r a g e plants on the study s i t e s (cm). Site Number Low-elevation Mid-elevation Species 1 3 4 2 5 Tsuga heterophylla A5.72 20.42 21.03 15.24 20.12 Thuja plicata - 15.24 15.24 106.70 -Tsuga mevtensiana - - - 45.72 -Gaultheria shallon - 15.24 15.24 20.42 26.52 Vaccinium alaskaense 30.48 33.53 15.24 36.88 19.51 Vaccinium parvifolium 20.12 29.87 15.24 34.44 24.99-Mean height of a l l forage species (± s-) 32.11 ± 3.75 22.86 ± 2.68 16.40 ± 1 . 4 7 43.23 ± 2.08 22.79 ± 1.84 Plants 137 cm or l e s s i n height, assuming the snow pack would not support the weight of a deer and allow feeding on t a l l e r plants. 4 0 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 visit 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. Jones (1975) observed differences of the same magni-tude. During the severe winter of 1971-72 he measured snow depths of 0.9 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 avail-ability 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 measure-ments, 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 in November followed by reductions in snow pack in December and January, and subsequent build-up of the snow pack in February to maximum depth in March. In the winter of 1973-74, February-March was the only period during which forage availability was substan-tially reduced at mid-elevations for an extended period of time. This winter was considered to be intermediate in severity from the standpoint Mid-elevatIon Si t e s 40 J 30-1 snow 20 depth (cm) 10-1 S i t e 2 U . ~l ^ T" f T " "T— Oct Nov Dec Jan Feb Mar Apr "-*0 Plant h t a 20 hio 40 30 -4 snow 20 depth (cm) . 10 Site 5 n i r i T 1~-—TT— Oct Nov Dec Jan Feb Mar Apr ,Plant ht (cm) Figure 2-2. Snow depths r e l a t i v e to plant height during the winter of 1973-74 mean height of combined forage plants 'study s i t e not established. Low-elevation Sites 40 3<M 20-10-1 T' 1 1 T- 1 r Oct Nov Dec Jan Feb Mar Apr 30 Plant ht (cm) 40 H 30 -20 -i 10 -Site 3 a XL X L T T ! "r T . Oct Nov Dec Jan Feb Mar Apr -40 .30 Plant ht (cm) L-20 10 40 -30. 20-10 1 S i t e 4 JD • n H40 h30 20 Plant ht (cm) Oct Nov Dec 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 ele-vation 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 litter 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 con-tinuous record of snowfall had been made, a closer relationship might have been apparent. An additional factor which obscures the snowfall-l i t t e r f a l l relationship is that snow melt often occurred between meas-urements of snow depth. Greatest forage l i t t e r f a l l occurred in the period February 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 L i t t e r f a l l Mid-elevation Sites ( k g - h a ^ . d y - 1 ) l i t t e r f a l l , , ,<? 5 -A -3 — depth 2 1 S i t e 2 T 1 r -er-n — i j o - 50 AO Oct N o v Dec Jan Feb Mar Apr snow 30 (cm) 20 10 L i t t e r f a l l ( k g -ha~ 1.dy _ 1) 5 4 -3 -2 ~ 1 S i t e 5 o t \ "i 1 T " — r - r 50 AO snow depth 30 (cm) I- 20 10 Oct Nov Dec Jan Feb Mar 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 study p e r i o d . L i t t e r f a l l 5 (kg-ha^-dy-1) 3 2 1 L i t t e r f a l l ( k g-ha~ 1.dy _ 1) 5 A 3 S i t e 1 Mid-elevation Sites 1 2 H 1 1 T * " — i — ' I " i f r — - r Oct Nov Dec Jan Feb Mar Apr S i t e 3 50 AO snow depth 30 (cm) 20 10 50 L. AO s n o w depth - 30 (cm) - 20 - 1 0 L i t t e r f a l l (kg-ha~ 1.dy" 1) 5 A --i 1 1 I — " r 1 r Oct Nov Dec Jan Feb Mar Apr 3-2_ 1-— i — i — r * n i T — T Oct Nov Dec Jan Feb Mar Apr L 50 h AO snow depth I-. 30 (cm) f- 20 10 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 poten-ti 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 depend-able forage supply. Forage l i t t e r f a l l amounted to 168 and 54 kg'ha 1 on mid- and low-elevation sites, respectively over the 180-day winter period. Comparable values for rooted forage plants are 153 and 42 kg'ha 1. In a winter with deep snow, rooted forage would be largely unavailable. 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 pro-vides 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 1, respectively on low- and mid-elevation sites. 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 maxi-mum stage of production. In summary, the relative availability of l i t t e r f a l l and understory vege-tation in some stands of mature conifers in winter approaches that meas-ured 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 pro-vides a continuing source of forage. SUMMARY Results of this portion of the study provide some preliminary indica-tions 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 in regard to both under-story vegetation and l i t t e r f a l l . Observations made are pertinent to the relatively "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 m3,ha 1) in stands studied above elevations of 450 m compared to low-elevation stands (1700 m3'ha_1). 2) 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 in 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 under-story forage as the low-elevation stands that were studied. 5) Lichens, primarily Alectoria spp., made up 86 percent of forage l i t t e r f a l l ; green conifer foliage contributed very l i t t l e forage relative to foliage available. 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 in 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 ob-servation is supported by previous research results indicating high levels of winter deer use of mature conifer stands. 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 (Wild-life) No. 74. Ontario Dept. of Lands and Forests. 134 pp. Bergerud, A.T. 1972. Food habits of Newfoundland caribou. J. Wildl. Manage. 35: 913-923. Boehm, W. 1972. Lichen occurrence in old-growth Douglas-fir, Ross Lake Basin. Master of Science Professional Paper. College of Forest Resources. Univ. of Washington. Book, S.A., G.E. Connolly and W.M. Longhurst. 1972. Fallout 1 3? Cs accu-mulation in two adjacent populations of northern California deer. Health Physics 22: 379-385. Bray, J.R. and E. Gorham. 1964. Litter production in forests of the world. Adv. in Ecol. Research. 2: 1-157. British Columbia Forest Service. 1962. Standard cubic-foot volume tables. B.C. Forest Service, Victoria, B.C. Brodo, I.M. and D.L. Hawksworth. 1977. Alectoria and allied genera in North America. Opera Botanica 42: 1-64. Stockholm. Brown, E.R. 1961. The black-tailed deer of western Washington. Washington State Game Dept. Biol. Bull. No. 13. 124 pp. Cliff, E.P. 1939. Relationship between elk and mule deer in the Blue Mountains of Oregon. Trans. N. Amer. Wildl. Conf. 4: 559-569. Cowan, I. McT. 1945. The ecological relationships of the food of the black-tailed deer, Odocoileus hemionus columbianus (Richardson) in the coast forest region of southern Vancouver Island, B.C. Ecol. Monogr. 15: 109-139. Cowan, I. McT., W.S. Hoar and J. Hatter. 1950. The effect of forest succession upon the quantity and upon the nutritive values of woody plants used as food by moose. Can. J. Res. 28, Sec. D., 249-271. Crete, M. and J. Bedard. 1975. Daily browse consumption by moose in the Gaspe Peninsula, Quebec. J. Wildl. Manage. 39: 368-373. Cringan, A.T. 1967. History, food habits and range requirements of the woodland caribou of continental North America. Trans. N. Amer. Wildl. Conf. 22: 485-501. 48 Crouch, G.L. 1964. Forage production and utilization in relation to deer browsing of Douglas-fir in the Tillamook Burn, Oregon. Ph.D. Thesis. Oregon State Univ., Corvallis. 162 pp. Daubenmire, R.F. 1959. A canopy-coverage method of vegetational analysis. N.W. Sci. 33: 43-64. Denison, W.C. 1973. Life in t a l l trees. Sci. Amer. 228: 74-80. Dimock, E.J. 1958. Litterfall in a young stand of Douglas-fir. N.W. Sci. 32: 19-29. Edwards, R.Y., J. Soos and R.W. Ritcey." I960. Quantitative observations on epidendric lichens used as food by caribou. Ecology 41: 425-431. 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. Grier, C.C. and R.S. Logan. 1977. Old-growth Pseudotsuga menziesii communities of a western Oregon watershed: Biomass distribution and production budgets. Ecol. Monogr. 47: 373-400. Harestad, A.S. 1979. Seasonal movement of black-tailed deer on northern Vancouver Island. Ph.D. Thesis. Faculty of Forestry. Univ. of British Columbia. 184 pp. Harshbarger, T.J. and B.S. McGinnes. 1971. Nutritive value of sourwood leaves. J. Wildl. Manage. 35: 668-673. Hash, H.S. 1973. Movements and food habits of the Lochsa elk. M.S. Thesis Univ. of Idaho. 76 pp. Hines, W.W. 1973. Black-tailed deer populations and Douglas-fir refor-estation 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. Foods eaten by the Rocky Mountain elk. J. Range Mgmt. 26: 106-113. 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 contrast-ing 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 Eco-systems - A Symposium. Bellingham, Washington, March 23-24, 1972. pp. 177-187. Rickard, W.H. 1975. Litterfall 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. 1970. Winter ecology of moose in the Gallatin Mountains, Montana. 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 litter 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 avail-able; 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 coni-fers were most prevalent in diets of deer from forested areas. Patterns of change in 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 in deer was met in 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 generally enhanced when they were part of forage mixtures. 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 characteris-tics 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. Know-ledge 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 is related to the nutritive quality of the forage plant (Swift 1948, Weir and Torrell 1959, Longhurst et al. 1968). Chemical composition and associated di-gestibility of plants determine the degree to which nutritional require-ments 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 al. 1977, Dietz 1972). My objectives in examining forage characteristics were: 1) To determine patterns of seasonal variation in chemical char-acteristics 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 is reduced and then becomes constant or decreases. Dry matter of rumen contents can reflect the moisture content of forage plants, which in turn influences their nutritive value. The objective of measuring characteristics of the rumens from deer col-lected 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 its envi-ronment. 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 differen-ti a l digestibility which occurs among plant species, and which can result in overestimation of those indigestible or slowly-digestible plants (Bergerud and Russell 1964). 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 food habits of black-tailed deer on southern Vancouver Island. 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 evalua-tion 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 con-sisted 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 f a l l -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. Types were shrubs, conifers, lichens, forbs and ferns. In addition, several minor types were defined and 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 con-sumed. 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) = I V o f f o r a g e i t e m x inn iv ^ ; j I y a U f Q r a g e i t e m s x lUU Importance Value (percent) provides a measure of forage use for an item relative to the use of other forage items. Since i t combines both fre-quency and volume of occurrence, 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 importance of forage types in the annual diet. Average annual percent IV for forage types are 35.5, 34.1, 11.0, 6.5 and 3.1 for forbs, shrubs, lichens, coni-fers 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 composi-tion of deer taken from these areas (Figure 3-1). Conifers occurred in greatest quantities during spring and the' fall-winter season, but in sub-stantial quantities only in rumens of deer from forested areas. Lichens S P R I N G SUMMER 2 F A L L - W I N T E R n = 2 F O R E S T E D Other 6.7 Conifers 12.3 Forbs 13.9 Ferns 8.0 Conifers 4.2 Other 3.6 n = 11 n - 11 n = 18 Grass 8.6 n = 28 C U T O V E R Gras9 2.9 Liverwort-moss 6.5 n = 13 Berries 4 . 4 Other 4 . 5 F O R E S T E D AND C U T O V E R Other 3.9 Ferns 3.0 n = 39 Conifers 11.1 Importance value 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 divided by the sum of importance values f o r a l l types. 2No samples were taken from deer i n forested areas i n summer. Figure 3-1. Seasonal importance values (%) for forage types consumed by b l a c k - t a i l e d deer i n forested and cutover areas. L n 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 f a l l -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 leaves year-round (e.g. Cornus canadensis and Linnaea borealis). April is a transition period between winter and spring relative to diet composition. Grasses, which are among the first plants to begin growth in spring appear in substantial quantities in the diet in April. Equisetum spp. also initiate growth and contribute significantly to the April 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. Growth of most shrubs does not begin until May. 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 Value (%) Jan Feb ' : Mar Apr \ . May Jun ' . ; J u l Aug Sep Oct Nov . Dec ( 3 ) 1 (5) . '1 : (8) (6) • ; : (7) ' (6) . (5) . ' (11) (2) \\ (A) . (9) (4) Figure 3-2. Monthly patterns of use of forage types by b l a c k - t a i l e d deer' for forested 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 in significant quanti-ties in spring rumens of deer from both areas. The summer diet in cutovers (no samples from forest in summer) differs l i t t l e 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 suc-culence 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 its greatest use at this time. The lichens Alectoria sarmentosa and Lobaria oregana are important components of the fall-winter diet of deer from forested areas. This change in diet associated with leaf f a l l in deciduous shrubs is the basis for distinguishing between summer and f a l l at the end of September. LEGEND 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 Lichens ALS A Forbs EPAN TITR COCA POPA LIBO Alectoria sarmentosa SPRING n = 2 FORESTED CUTOVER Epilobium angustifolium Tiarella trifoliata Cornus canadensis Potentilla pdlustris Linnaea borealis Other 4.6 BLSP 3.3 EPAN 3.3 TITR 4.1 TSHE 4.5 PTAQ 5.3 n = 11 Other 6.3 Grass 3.3 •VACC 4.8 POPA 5.2 SUMMER n = 18 her 8.6 LYAM 3.5 RUBE 4.2 VACC 6.3 FALL-WINTER RUBUS .11. n = 11 Other 4.8 Fungi 2.9 L.wort 3.5 TSHE 4.0 THPL 5.9 28 Other 10.4 COCA 3.7 THPL 4.8 LIBO 5.2 BLSP 5.5 Grass 10.0 EQUIS 10.0 Ferns BLSP PTAQ Other Grass LYAM L.wort= Fungi = EQUIS = Blechnum spicant Pteridium aqualinum grass spp. Lysichitum americanum liverwort Fungi Equisetufn spp. FORESTED/ AND CUTOVER RUBUS 49.5 • n = 13 I EPAN VS. -J-Other 8.9 \ 25.0 Y zr-—COCA 8.0 VACC 8.6 THPL = 39 Other 11.0 Grass 3.3 EQUIS 3.3 BLSP 3.3 Fungi 3.1 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 divided by the sum of IVs for a l l species. Figure 3.3 Seasonal patterns 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 in Appendix Tables 8, 9 and 10. The perennial forbs Cornus canadensis and Linnaea borealis are well repre-sented in the diet in 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 re-flected in composition of rumen contents. Deer appeared to be opportunis-tic 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). Forbs and shrubs were of equal importance in the year-long diet as indicated by annual Importance Values. Epilobium  angustifolium clearly dominated 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 lium i r J F M A M J J A S (3) 1 (5) (8) (6) (7) (6) (5) (11) (2) MONTH 1Number of rumens analyzed. N D (9) (4) Figure 3-4. Monthly pattern of use by black-tailed deer of forage species i n forested and cutover areas. 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 con-sumed 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 pref-erence. 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. Cowan (1945) made a similar observation as did Jones (1975) who observed fewer species in rumens of deer in a severe winter compared to a mild one. Phenological changes in 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 meas-ured by Van Soest feed analyses. Dry Matter Content Dry matter content is 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 there-fore increases; lignin and cellulose concentrations increase and digesti-bility declines (Short 1971). Bissel et al. (1955) discuss how the proportion of dry matter in a forage species is related to the avail-ability 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. Dry matter digestibility of most plants is highest at this time. However, because of the high moisture content, greater food intake may be required for a level of nutrient intake equiva-lent 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. Crude protein consists of both protein and non-protein nitrogen (Wood et al. 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 al. 1955) and fawns (Ullrey et al. 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 diets. French et a_l. (1955) suggested that diets of 13 to 16 percent result i n optimum growth of white-tailed deer. Dietz (1965) noted that when dietary protein levels f a l l below 6 to 7 percent, rumen function i s adversely affected. Cowan et a l . (1970) observed that protein levels are often related to levels of other nutrients i n plants. These investigators indicated that for some combinations of natural foods eaten by deer, i f an adequate per-centage of crude protein i s present, other nutrient requirements may be i n c i d e n t a l l y covered. 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 ade-quate protein. A s i g n i f i c a n t positive correlation exists between crude protein and d i -gestible protein (Sullivan 1962) so that the crude protein l e v e l of a forage provides a reasonably r e l i a b l e indicator of feed value. I t should be recognized that there may be exceptions, such as that noted above. Protein levels may vary greatly between species and within species with phenological stage, plant portion and s o i l f e r t i l i t y . Dietz (1972) reviewed soil-plant-nitrogen relations. Einarsen (1946) noted increased protein levels i n forage plants eaten by black-tailed deer on burned s i t e s ; apparently the result of nitrogen mobilized i n the f i r e becoming available to the plants. High levels of protein occur only when plant growth i s rapid (Short 1971). As tissues mature, nitrogen content i s diluted by the rapid accumulation of carbohydrates, 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 in 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 "artificial 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 acid-pepsin 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 live animals, large samples and much time in collecting and weighing feed, feces and urine. 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 al. 1966, Johnson and Dehority 1968, Ruggiero and Whelan 1976). In addition, Baumgardt et al. (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 al. 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 coeffi-cients 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. Short (1963) found that digestibility of the same plants with ihocula from cattle and deer rumens gave different results. Nowlin (1974) noted differences in forage plant digestibility in inoculum from elk and cattle. However, Palmer et al. (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, turnover rate, of feedstuffs varies with their physical properties. Mautz and Petrides (1971) estimated a rumen retention time of 14 to 19 hours for succulent (and presumably di-gestible) foods of white-tailed deer. For a more fibrous hay meal, Cowan et al. (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. Readily-digestible cell contents (simple sugars, protein, starch, etc.) are soluble in neutral-detergent solution while the cell wall contents (neutral-detergent fibre-NDF) are not. Hemicellulose, a major component of 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 acid-detergent fibre (ALT). Treatment of the ADF fraction with sulfuric acid which dissolves cellulose, followed by ashing estimates the lignin frac-tion. Lignin (L) is the most important factor limiting cell wall digesti-bility (Goering and Van Soest 1970). In summary, the Van Soest method of chemical solubility partitions forage according to its 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 di-gestibility of cell wall contents of twigs was less than that of herbages. Short et al. (1973) found that the summative equation to predict digesti-bility 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 al. (1972) 74 with Sassafras albidum twigs. Following chemical removal of l i g n i n , d i g e s t i b i l i t y increased from the normal 16 to 19 percent to 75 to 79 percent. In comparisons of laboratory techniques for predicting 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 constituents, acid-detergent l i g n i n provided the best predictor of d i g e s t i b i l i t y within forage species but that i n v i t r o d i g e s t i b i l i t y of dry matter was a superior predictor for a variety of forage species and mixtures. 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 vivo dry matter d i g e s t i b i l i t y of white-tailed deer feed. Results discussed above d i f f e r with respect to the correlation observed between detergent-fibre analyses and i n vivo or i n v i t r o d i g e s t i b i l i t y . Variation probably results from the use of s l i g h t l y different procedures or the varied forages studied. This system of feed analysis does provide a r e l a t i v e l y simple means of pa r t i t i o n i n g feeds and forages according to the r e l a t i v e d i g e s t i b i l i t i e s of th e i r components. In th i s respect i t overcomes several of the limit a t i o n s associated with the proximate analy-sis method of forage evaluation (Dietz 1972). S o l u b i l i t y of Forage The proportion of a forage which i s soluble i n a r t i f i c i a l s a l i v a (McDougall 1948) provides a measure of readily-available nutrient con-tent. Pearson (1970) observed that s o l u b i l i t i e s of forages did not 75 correlate significantly with in vitro digestibility and concluded i t was of no value in predicting forage digestibility. Conversely, Uresk et aJL. (1975) determined solubility of several species in various components of the Tilley and Terry (1963) in vitro system and observed that Arcto-staphylus uva-ursi incubated in artif i c i a l saliva underwent a loss in dry matter equal to 85 percent of its in vitro digestibility. They attributed this high solubility to the species' high intra-cellular carbohydrate and mineral content and suggested this may help explain its 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 readily-soluble cell contents. Solubility was examined in this study relative to other forage quality parameters to further evaluate its 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 activi-ties which modify species composition and abundance in the habitat (Urness et al. 1975). Although data on individual species are useful and neces-sary to understanding deer nutrition, wild deer seldom consume mono-specific diets. 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 sig-nificantly 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 carbo-hydrates, than to the 2-component diet. In deer feeding in the natural habitat Pearson (1969) also noted 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. Collection areas were usually near a l i t t e r f a l l study site. 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 fairly accessible during periods of deep snow. The 10 forage species collected monthly were those known from previous food habits to be important food items. Species sampled within the 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 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. angusti-folium 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 difficult 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 labora-tory 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 difficult 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 its junctions with the esophagus and omasum, removed from the animal and weighed. 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 its 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 or in the Weyerhaeuser Company research lab in Seattle, Washington. 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 con-stant 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 buffer solution (McDougall 1948) and fresh rumen inoculum. 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 first 4 hours and at 8-hour intervals thereafter. At the end of this period, samples were filtered under suction through pre-weighed fritted glass crucibles. Residues were washed with distilled water and with acetone until the filtrate was clear. Oven-dry residue weights were then deter-mined. Duplicate flasks containing only rumen inoculum and buffer solu-tion (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 -^QQ DDM beginning sample wt (0.5g) 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 trials were also conducted to determine rates of digestion. 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 in the digestion rate trials. Individual deer were collected to provide inoculum for each of these trials. 8 3 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 repre-sentative mixtures although at the time this study was started, food habits data were limited or entirely lacking for some seasons. Rumen inoculum for the DDM 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 in 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. angusti-folium) 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 characteristics of forage collected from forested (F) and cutover areas (C) in d i f f e r e n t seasons. Comparisons are made between forage types within each season and annually. N Dry Matter Crude Protein x DDM 1 Season -Forage Type F C F + C F (Percent of green weight) — C F+C 1 F (Percent of oven dry weight) — C F+C (Percent of — oven dry weight) — F C F+C Spring Shrubs 6 6 12 22A.A a  3 ( 8.1) 28. 5 a ( 7.2) 26. 5 a ( 7.6) 15. 5 a ( 5.3) 1A.53 (15.9) 15.0 a (15.A) A2.93 (17.A) 44. 5 a (17.6) 43. 7 a (16.7) Conifers 6 6 12 A7.6 b ( 5.A) 40.9 b (10.7) AA.2b ( 8.8) 5.2b ( 1.2) 7.2b ( 2.8) 6.2b ( 2.3) A2.6a ( 8.4) 46.5 ab (12.9) 44.5 a (10.6) Lichens 2 - 2 73. 6 C (23.2) - 2.1 b ( 0 . 1 ) - - 48. 2 a ( 3 . 2 ) - -Forbs • - 2 2 - 17.0 a c ( 2.8) - - 2A.5C ( 0.7) - - • 66.8 b ( 3 . 2 ) -Ferns 4 A 8 13. 2 a ( 3.2) 17.0 a c ( A.A) 15. l d ( A.l) 18.5° ( A.5) 20.0 a c ( A.A) 19.2° ( A.2) 25.4b ( 8.1) 21.5C ( 3.8) 23.4C ( 6.2) Summer Shrubs 8 8 16 26. 6 a ( A.l) 36. 2 a ( A.l) 31.A a b ( 6.A) 10.3 a ( 2.A) 8.6a ( 1.0) 9.4a ( 2.0) 37.4 a c ( 8.5) 39.8 a c ( 1 2 . 9 ) 38.6a (10.6) Conifers 7 7 IA 39.2 b (10.1) 31.8 a b ( 3.5) 35. 5 a ( 8.2) 5.5b ( 1.2) 5.9b ( 0.3) 5.7b ( 0.9) AA.8a ( 7.9) ' 48.6 a ( 9.1) 46.7 b ( 8.4) Lichens 3 - 3 88. l c ( A.5) - 1.9C ( 0.6) • - • - 75.8b ( 3.2) . Forbs. - 2 2 - 22.7° (0.6) - - 13.9° ( 3.3) - • . - 74.5 b ( 3.5) ' - -. Ferns 4 A 8 22.8 a ( 8.3) 27.8 b c ( 5.6) 25.3d (7.1) 1 2 . l a ( 1.7) 8.1 a ( 0.7) 10. i a ( 2.5) 28.5C ( 8.4) 30. 7 C (10.1) 29.6d ( 8.7) Table 3-1. continued. Dry Matter Season (Percent of green weight) — C r u d e P r o t e i n ( P e r c e n t o f — o v e n d r y w e i g h t ) x DDM ( P e r c e n t o f o v e n d r y w e i g h t ) F o r a g e T y p e F C F + C F c F+C F c F+C F c F+C F a l l - W i n t e r S h r u b s 2 0 22 42 3 5 . 5 a 3 8 . 3 a 3 6 . 9 a 7 . 1 3 6 .4 a 6 .7 a 35.5 a 38 . 3 a 37 .0 a ( 5 . 5 ) ( 3 . 0 ) ( 4 . 5 ) ( 1.7) ( 1.4) ( 1.6) ( 8 . 1 ) ( 9.2) ( 8.7) C o n i f e r s 21 21 42 4 5 . 2 b 4 1 . 3 b 4 3 . 3 b 5 . 2 b 6 . 1 a b 5.6 a 46 .3 b 46 . 7 b 46 . 5 b ( 3 . 4 ) ( 3 .2) ( 3.8) ( 0.8) ( 1.1) ( 1.0) ( 4.7) ( 9.9) ( 7.6) L i c h e n s 7 - 7 38.2° (20.8) - -( 1.8 C 0.3) - - 78. l c (14.2) - -F o r b s • - 1 1 - 28. 9 C ( - ) - -( 5 .5 b - ) - ' - 74 .0 C ( - ) -F e r n s 12 12 24 23. 2 d 2 6 . 3 C 24 .7 d 8 . 9 d 8 . 1 c 8 .5 C 33.0 a 37. l a 3 5 . l a ( 5 . 8 ) ( 6 . 4 ) ( 6.2) ( 1.2) ( 1.0) ( 1.2) (11.0) (14.0) (12.5) A l l - y e a r S h r u b s 34 36 70 31. 5 a 36. 2 a 3 3 . 9 a 9 . 3 a n 8.2 8 .8a 37.3 n 39 .7 a 38 .5 a ( 7 . 4 ) ( 5.4) ( 6.8) ( 4.2) ( 3.9) ( 4.0) (10.3) (11.6) (11.0) C o n i f e r s 34 34 68 44 . 4 b 3 9 . 3 b 41 .8 b 5 .3 b 6 .2 b 5.7 b 45 .3 b 47 . 0 b 46 .2 b ( 6.2) ( 6.4) ( 6.7) ( 1.0) ( 1.5) ( 1.3) ( 6.1) (10.0) ( 8.3) L i c h e n s 12 - 12 74. 0 C (19.1) - 74.0 C (19.1) ( 1.9 C 0.3) - 1.9° ( 0.3) 72.5 C (15.6) - 72.5 C (15.6) F o r b s - 5 5 - 21 .7 C 21.7 d • - 16 .5 C 16 .5 d _ 71.3° 71 .3 C ( 5.1) ( 5.1) ( 8.3) ( 8.3) ( 4.8) ( 4.8) F e r n s 20 20 20 21. l d 24. 7 C 22 .9 d 11 .5 d 10 .5 d 11. o e 30.6 d 32 .7 d 31. 6 d ( 7.0) ( 7 . 0 ) ( 6.9) ( 4.3) ( 5.3) ( 4.8) (10.1) (13.1) (11.6) ^ 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 n d i c a t e d i s m e a n 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 e a c h m o n t h . 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 S 0 . 0 5 l e v e l a s d e t e r m i n e d b y 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 . S t a n d a r d d e v i a t i o n . 87 ably explains their similarity in dry matter content, although data pre-sented later indicate ferns contain high levels of fiber. Seasonal com-parisons of forage types also are presented 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. These differences were expected, considering the varied li f e 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 con-tent. Also, Alectoria is 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 clipped foliage in absorbent paper prior to obtaining green weights. The exception was A. sarmentosa, which apparently absorbed precipitation. 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 c o m p a r i s o n o f c h a r a c t e r i s t i c s 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 ) a n d c u t o v e r ( C ) a r e a 3 i n d i f f e r e n t s e a s o n s . C o m p a r i s o n s a r e m a d e b e t w e e n s e a s o n s a n d a r e a o f c o l l e c t i o n f o r e a c h f o r a g e t y p e . N D r y M a t t e r C r u d e P r o t e i n x D D M 1 ( P e r c e n t ( P e r c e n t o f ( P e r c e n t o f o f g r e e n w e i g h t ) o v e n d r y w e i g h t ) o v e n d r y w e i g h t ) F C F+C F C F+C F C F+C F C F+C S h r u b s S p r i n g 6 6 12 a 2 4 . 4 2 a 2 8 . 5 + + 3 a 2 6 . 5 a 1 5 . 5 a 1 4 . 6 a 1 5 . 0 a 4 2 . 9 a 4 4 . 5 a 4 3 . 7 ( 8 . 1 ) " ( 7 .2) ( 7 .6) ( 5 .3) ( 5 .9) ( 5 .4) (17.4) (17 .6 ) (16 .7 ) Summer 8 8 16 a 2 6 . 7 b 36 .3++ b 3 1 . 4 b 1 0 . 3 + b 8 . 6 b 9 . 4 a 3 7 . 4 a 3 9 . 8 a 3 8 . 6 ( 4 .1 ) ( 4 . 1 ) ( 6 . 4 ) ( 2 .4) ( 1.0) ( 2 .0) ( 8 .5) (12 .9) (10 .6) F a l l - W i n t e r 20 22 42 b 3 5 . 5 b 38 .3++ C 3 6 . 9 c 7 . 1 + c 6 . 4 C 6 . 7 a 3 5 . 5 a 3 8 . 3 a 3 7 . 0 ( 5 .5) ( 3 .0 ) ( 4 .5 ) ( 1.7) ( 1.4) ( 1.6) ( 8 .1) ( 9 .2) ( 8 .7 ) A n n u a l 34 36 70 31 .5 36.2++ 33 .9 9.3 8.2 8.8 37.3 39.7 38 .5 ( 7 .4) ( 5 .4) ( 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 4 7 . 6 + 8 4 0 . 9 a 4 4 . 2 a 5 . 2 a 7 . 2 3 6 . 2 a 4 2 . 6 a 4 6 , .5 a 4 4 . 5 ( 5 .4 ) (10 .7) ( 8 .8) ( 1.2) ( 2 .8) ( 2 .3) ( 8 .4) (12, .9) (10 .6) Summer 7 7 14 b 3 9 . 2 b 3 1 . 8 b 3 5 . 5 a 5 . 5 "5.9 a 5 . 7 a 4 4 . 8 3 4 8 . .6 a 4 6 . 7 (10 .1) ( 3 .5 ) ( 8 .2 ) ( 1.2) ( 0 .3) ( 0 .9) ( 7.9) - ( 9. • 2) ( 8 .4 ) F a l l - W i n t e r 21 21 42 a 4 5 . 2 + + a 4 1 . 3 3 4 3 . 3 a 5 . 2 a 6 .1++ a 5 . 6 a 4 6 . 3 a 4 6 . .7 a 4 6 . 5 ( 3 .4 ) ( 3 .2 ) ( 3 .8) ( 0 .8) ( i . i ) ( 1.0) ( 4 .7) ( 9. .9) ( 7 .6) A n n u a l 34 34 68 44.4++ 38 .3 41 .8 5.3 6.2++ 5.7 45.3 47. 0 46 .2 ( 6 .2) ( 6 .4) ( 6 .7) ( 1.0) ( 1.5) ( 1.3) ( 6.1) (10. 0) ( 8 .3) L i c h e n s S p r i n g 2 2 a 7 3 . 6 a 2 . 1 a 4 8 . 3 (23 .2) ( 0 .1) ( 3 .2) Summer 3 3 a 8 8 . 1 a 2 . 0 b 7 5 . 8 ( 4 .5 ) ( 0 .6) ( 3 .2) F a l l - W i n t e r 7 7 a 3 8 . 2 ^ a 1 . 8 b 7 8 . 1 (20 .8 ) ( 0 .3) (14.2) A n n u a l 12 12 7 4 . 0 1.9 72.5 (19 .1) ( 0 .4) (15.6) CO 00 Table 3-2.continued. N Dry M a t t e r Crude P r o t e i n x DDM1 F C F+C F ( P e r c e n t of green w e i g h t ) C F+C F (Per c e n t o f oven d ry we i g h t ) C F+C F (Percent oven d r y we C of i g h t ) F+C Forbs Spring 2 2 a17.1 ( 2.8) a24.5 ( 0.7) a66.8 ( 3.2) Summer 2 2 a b22.8 (0.6) b13.9 ( 3.3) a74.5 ( 3.5) Fall-Winter 1 1 b28.9 ( - ) b5.5 ( - ) a74.0 ( - ) Annual 5 5 21.7 ( 5.1) 16.5 ( 8.3) 71.3 ( 4.7) Ferns Spring 4 A 8 a i 3 . 2 ( 3.2) a17.0 ( 4.4) a15.1 ( A.l) a18.5 ( 4.5) a20.0 ( A.A) a19.2 ( 4.2) a25.4 ( 8.1) a21.5 ( 3.8) a23.4 ( 6.2) Summer A A 8 b22.9 ( 8.3) b27.9 ( 5.6) b25.3 . ( 7.1) b21.1+ ( 1.7) b8.1 ( 0.7) b10.1 ( 2.5) a28.5 ( 8.4) a b30.8 (10.1) a b29.6 ( 8.7) Fall-Winter 12 12 2A b23.2 ( 5.8) b26.3+ (6.4) b24.7 : ( 6.2) C8.9+ ( 1.2) b8.1 ( 1.0) b8.5 ( 1.2) a33.0 (11.OV b37.1 (14.0) b35.1 (12.5) Annual 20 20 40 21.1 ( 7.0) 24.7 ( 6.9) 22.9 ( 7.1) 11.5 ( 4.3) 10.5 ( 5.3) 11.0 ( 4.8) 30.6 (10.1) 32.7 (13.1) 31.6 (11.6) 'Average d ry 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 of two r e p l i c a t i o n s f o r each of two deer per month. Valu 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 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 . 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) 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 . Standard d e v i a t i o n . 90 statistically different (p < 0.05) between a l l seasons in shrubs (Table 3-2). 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 in 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 cut-overs 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 in 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. Dry matter levels were similar and in most cases were not sig-nificantly different between species within a forage type as will be discussed further below. When species in a type were compared as to annual dry matter content in forested versus cutover areas, conifer species did not differ from each T a b l e 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 at d i f f e r e n t S t a t i s t i c a l compar i sons a r e made between seasons and a r e a o f c o l l e c t i o n . s e a s o n s . Dry M a t t e r ( P e r c e n t o f g r e e n w e i g h t ) Crude P r o t e i n ( P e r c e n t o f oven d r y we ight ) x DDM ( P e r c e n t o f oven d r y w e i g h t ) C F+C F+C F+C Shrubs Gaultheria shallon S p r i n g 2 2 4 Summer 3 3 6 F+C F a l l - W i n t e r A n n u a l 8 14 11 13 24 a b 2 6 . 6 ( 1 5 . 8 ) 3 b 2 4 . 5 ( 6 .4 ) a 3 6 . 6 ( 1 .5) 3 1 . 5 ( 8 . 3 ) a 3 1 . 3 2 (13 .1 ) a 3 4 . 3 ( 4 .1 ) a 3 7 . 3 ( 1 .5) 35.7+ ( 4 . 9 ) 29 .0 (12 .2) a 2 9 . 4 ( 7 .2) b 3 7 . 0 ( 1 .4) 33 .8 ( 6 .9) ° 1 0 . 8 ( 6 .9) a b 7 . 8 ( 0 .8) b 5 . 0 ( 0 .4) 6.8 ( 3 .2) "9.0 ( 2 .9) a 7 . 4 ( 0 .03) b 5 . 3 ( 0 .7) 6.3 ( 1.8) a 9 . 9 ( 4 .4 ) a 7 . 6 ( 0 .6) b 5 . 1 ( 0 .6) 6.5 ( 2 .5) "22.5 (10.6) a 27.8+ 1 * ( 1 a 9) 26 .6 ( 4 .0 ) 26.2 ( 4 .8) a 2 3 . 0 ( 2 .1 ) 3 2 4 . 5 ( 1.7) b 3 3 . 3 + ( 4 .8 ) 29.7 ( 6 .1) "22.7 ( 6 .3) a 2 6 . 2 ( 2 .4 ) b 3 0 . 4 ( 5 .4) 28.1 ( 5 .8) Vaccinium alaskaense S p r i n g 2 2 Summer 3 3 F a l l - W i n t e r 7 14 21 .1 ( 5 . 9 ) a b 2 6 . 4 ( 0 .5 ) b 3 3 . 6 ( 7 .1) "26.7 ( 7 .8) b 3 7 . 2 ( 4 .1 ) b 3 7 . 5 + ( 3 .4 ) 23 .9 ( 6 .5) a b 3 1 . 8 ( 6 .5) b 3 5 . 6 ( 5 .7) "17.5 ( 3 .9) b 1 2 . 4 ( 1.8) C 7 . 8 ( 1.1) "14.9 ( 5 .5) b 9 . 7 ( 0 .2) b 6 . 9 ( 1.6) A n n u a l 12 12 24 29 .8 ( 7 .5) 35.7++ ( 5 .7 ) 32.7 ( 7 .2) 10.5++ ( 4 .1 ) 8 .9 ( 3 .7) V. parvifolium S p r i n g 2 2 4 3 2 5 . 6 3 2 7 . 5 a 2 6 . 5 3 1 8 . 2 a l 9 . 7 ( 2 .8 ) ( 1 .5) ( 2 .1) ( 3 .7) ( 4 .4 ) Summer 2 2 4 a b 3 0 . 2 b 3 7 . 7 b 3 3 . 9 b 10.9++ b 8 . 6 ( 0 .6 ) ( 5 .9 ) ( 5 .5) ( 0 .4) ( 0 .4) F a l l - W i n t e r 7 7 14 b 3 6 . 4 b 4 0 . 1 + b 3 8 . 2 b 8 . 3 + b 7 . 1 ( 6 .1 ) ( 3 .4 ) ( 5 .1) ( 1.1) ( 1.0) A n n u a l 11 11 22 33 .3 37.3++ 35.3 10 .5 9 .7 ( 6 .6 ) ( 5 .9) ( 6 .5) ( 4 .2 ) ( 5 .2) 16.2 ( 4 .1) b 1 1 . 0 ( 1.9) C 7 . 3 ( 1.4) 9.7 ( 3 .9) "51.0 ( 9 .9) a b 4 1 . 0 ( 1.7) b 3 6 . 2 ( 4 .9) 39.9 ( 7.4) "56.5 (12 .0) a b 4 7 . 7 ( 3 .6) b 3 5 . 8 ( 9 .0 ) 42 .2 (11 .5) 53 .7 ( 9 .5 ) b 4 4 . 3 ( 4 . 4 ) ° 3 6 . 0 ( 7 .0) 41 .9 ( U . 3 ) 18 .9 ( 3 .4) b 9 . 8 ( 1.3) b 7 . 7 ( 1.2) 10.1 ( 4 .7) "55.3 ( 6.0) a b 4 6 . 5 ( 3 .5) b 4 2.5 ( 5.9) 45 .5 ( 7.2) "54 .0 ( 3 .5 ) a 5 1 . 0 + ( 1 . 4 ) a 4 6 . 4 ( 8 .5) 4 8 . 6 ( 7 . 4 ) 54 .6 ( 4 .1 ) 3 b 4 8 . 7 ( 3 . 4 ) b 4 4 . 4 ( 7 .3) 47 .1 ( 7 .3) Table 3-3. continued. N Dry Matter Crude Protein x DDM (Percent (Percent of (Percent of of green weight) oven dry weight) oven dry weight) — -F C F+C F C F+C F C F+C 1 C F+C Conifers Pseudotsuga menziesii Spring 2 2 4 a50.0 a39.4 a44.7 a5.8 a9.8 a7.8 a44. 5 a47 .3 a45.9 ( 2.0) (12.2) ( 9.4) ( 0.6) ( 2.9) ( 2.9) ( 4. 2) (14 • 5) ( 8.9) Summer 2 2 4 b33.5 a33.6 b33.6 a6.3 b6.3 36.2 346. 3 a52 .0 a49.1 (10.3) ( 4.9) ( 6.6) ( 1.5) ( 0.1) ( 0.9) ( 3. 9) ( 2 • 1) ( 4.2) Fall-Winter 7 7 14 a45.4+ a40.8 a43.1 a5.9 b7.4++ a6.6 a47. 4 a47 .2 a47.3 ( 4.2) ( 4.1) ( 4.6) ( 0.7) ( 0.3) ( 0.9) ( 1. 9) ( 4 .1) ( 3.0) Annual 11 11 22 44.1+ 39.3 41.7 6.0 7.6++ 6.8 46. 7 48 .1 47.4 ( 7.2) ( 5.9) ( 6.9) ( 0.7) ( 1.5) ( 1.4) ( 2. 6) ( 5 • 9) ( 4.5) Thuja plicata Spring 2 2 4 a50.2 a46.4 a48.3 a4.4 a4.8 a4.6 350. 0 a57 .1 a53.6 ( 2.2) ( 7.3) ( 4.9) ( 0.9) ( 0.5) ( 0.6) ( 6. 4) ( 1 •2) ( 5.6) Summer 3 3 6 a b46.9+ b32.3 b39.6 a5.0 b5.7 a b5.4 a50. 5 a54 .8+ a52.7 ( 0.9). ( 0.3) ( 8.0) ( 0.4) ( 0.1) ( 0.4) ( 3. 5) ( 3 • 7) ( 4.0) FalJ-Winter 7 7 14 b45.0+ c41.2 a b43.1 a4.9 b5.7+r b5.3 a50. 3 a57 .6++ a53.9 ( 2.3) ( 2.8) ( 3.1) ( 0.4) ( 0.6) ( 0.7) ( 2. 4) ( 2 .8) ( 4.5) Annual 12 12 24 46.3++ 39.8 43.1 4.9 5.6++ 5.2 50.3 56 .8 53.5 ( 2.7) ( 5.8) ( 5.5) ( 0.5) (0.6) ( 0.6) ( 3. 0) ( 2 .9) ( 4.4) Tsuga heterophylla Spring 2 2 4 a42.6 a b37.0 a b39.8 a5.4 a7.0+ a6.2 a33. 3 a35 .0 a34.1 ( 7.8) (16.5) (11.0) ( 2.1) ( 2.4) ( 2.1) ( 1. 8) . (11 • 3 > ( 6.7) Summer 2 2 4 a33.3 b29.3 a31.3 a5.5 a b5.8 a5.6 a b34. 8 a35 .8 a35.2 (14.0) ( 5.4) ( 9.0) ( 2.1) ( 0.6) ( 1.3) ( 5. 3) ( o • 4) ( 3.1) Fall-Winter 7 7 14 a4 5.1 a42.0 b43.6 a4.8 b5.1 a4.9 b41. ].++ a35 .4 a38.2 ( 3.9) (3.1) ( 3.8) ( 0.9) ( 0.4) ( 0.7) ( 3. 6) ( 3 .5) ( 4.5) Annual 11 11 22 42.5+ 38.8 40.6 5.0 5.6+ 5.3 38. 5 35 .4 36.9 ( 7.5) ( 7.9) ( 7.8) ( 1.2) ( l . D ( 1.2) ( 9) ( 4 .5) ( 4.8) Tab le 3-3. continued. N Dry Matter Crude Protein ,x DDM1  (Percent (Percent of (Percent of of green weight) oven dry weight) ' oven dry weight) F C F+C F C F+C F C F+C F C F+C Lichens Alectoria earmentoaa S p r i n g 2 2 a 7 3 . 6 a 2 . 1 a 4 8 . 2 (23 .2 ) ( 0 .1) ( 3 .2) Summer 3 3 a 8 8 . 1 a 2 . 0 b 7 5 . 8 ( A . 5 ) ( 0 .6) ( 3 .2) F a l l - W i n t e r 7 7 a 3 8 . 2 a 1 . 8 b 7 8 . 1 (20 .8 ) ( 0 .3) (14.2) A n n u a l 12 12 7 4 . 0 1.9 72.5 (19 .1 ) ( 0 .3) (15.6) Forbs Epilobium angustifolium S p r i n g . 2 2 a 1 7 . 1 a 2 4 . 5 a 6 6 . 8 ( 2 .8 ) ( 0 .7) ( 3 .2 ) Summer 2 2 a b 2 2 . 8 b 1 3 . 9 a 7 4 . 5 ( J u l y - O c t ) ( 0 . 6 ) ( 3 .3) ... ( 3 .5) F a l l - W i n t e r 1 1 b 2 8 . 9 b 5 . 5 a 7 4 . 0 ( - ) ( - ) ( - ) A n n u a l 5 5 21 .7 16 .5 71.3 ( 5 .1 ) ( 8 .3 ) ( 4 . 8 ) Table 3-3. continued. Dry Matter (Percent of green weight) Crude Protein (Percent of — oven dry weight) — x DDM (Percent of oven dry weight) F C F+C F C F+C F C F+C F C F+C Ferns Blechnum epicant Spring 2 2 . 4 a l 0 . 5 ( " ) ai6.5+ ( 1 . 1 ) a l 3 . 5 ( 3.5) a17.5 ( 7.1) a23.6 ( 1.8) a20.5 ( 5.5) a23.0 (12.0) a23.5 ( 4.9) a23.2 ( 7.5) Summer 2 2 4 a16.8 ( 1.2) b23.1+ ( 0.4) b19.9 ( 3.7) a b12.4 ( 0.1) b7.5 ( 0.2) b9.9 ( 2.8) a b35.8 ( 0.4) a b38.8 ( 5.3) b37.2 ( 3.5) Fall-Winter 6 6 12 b18.6 ( 1.5) b21.9+ ( 3.3) b20.3 ( 3.0) b9.0+ ( 1.5) b7.7 ( 1.3) b8.3 ( 1.5) b42.0 ( 7.9) b48.5 (10.1) b45.2 ( 9.3) Annual 10 10 20 16.6 ( 3.5) 21.0++ ( 3.5) 18.8 ( 4.1) 11.4 ( 4.3) 10.8 ( 6.8) 11.1 ( 5.6) 37.0 (10.6) 41.5 (13.0) 39.3 (11.8) Po lye tichion mm i turn Spring 2 2 4 a15.9 ( 1 . 1 ) b17.6 ( 7.4) a16.7 ( 4.4) a19.5 ( 2.5) a16.4 ( 1.5) a17.9 ( 2.5) a27.8 ( 5.3) a19.5 ( 1.4) 23.6 ( 5.7) Summer 2 2 . 4 b28.9 ( 7.6) a32.6 ( 1.3) b30.8 ( 4.9.) b11.9 ( 2.9) b8.7 ( 0.2) b10.3 ( 2 . 5 ) a21.3 ( 0.4) a22.7 ( 4.6) 22.0 ( 2.,8) Fall-Winter 6 6 12 b27.7 ( 4.8) a30.7 ( 5.7) b29.2 ( 5.2) b8.8 ( 0.9) b8.5 ( 0.5) b8.7 ( 0.7) a24.0 ( 2.9) a25.7 ( 4.4) 24.9 . ( 3.6) Annual 10 10 20 25.6 ( 6.7) 28.5 ( 7.6) 27.0 ( 7.1) 11.6+ ( 4.6) 10.1 ( 3.3) 10.9 ( 4.0) 24.2 ( 3.5) 23.9 ( 4.5) 24.1 ( 3.9) 'Average dry matter d i g e s t i b i l i t y , value i s mean of two r e p l i c a t i o n s per deer per month. 2Values i n a column w i t h a common superscript 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 ana l y s i s of variance and Scheffe's t e s t . 'Standard deviation. ''Significant 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 indicated 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. 96 other nor did shrub species. Polystichum muniturn was higher (p < 0.05) in dry matter content than Blechnum spicant in both forested and cutover areas. Annual levels of dry matter content between a l l species were also compared s t a t i s t i c a l l y using analysis of variance and Scheffe's test (Table 3-4). Patterns of variation were similar among species within forage types, i.e. conifer species did not differ from each other nor did shrub species, but individual species in both types differed from a l l other species in the other types. Annual levels of dry matter ranged from 74.0 (±5.5%) in A. sarmentosa to 18.8 (±4.2%) in Blechnum spicant. In summary, forage species examined in this study exhibited patterns of variation in dry matter content that were related to phenological stage of the plant. Similar patterns were documented by Short et aJL. (1975) in a number of browse species in the southeastern United States. Levels and patterns of change were similar within plant types. 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 s t a t i s t i c a l l y compared in Tables 3-1, 3-2 and 3-3. Annual levels of crude protein and other components are presented graphi-cally in Figure 3-5. On an annual basis, the single lichen examined, Alectoria sarmentosa, was lowest (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 nutrient l e v e l s of forage species. Values are averages for plants c o l l e c t e d i n forested and cutover areas combined. DRY M A T T E R (% OF G R E E N W E I G H T ) ALSA THPL1 PSME TSHE VAPA GASH VAAL POMU EPAN BLSP ' / / / / / / / / / / / / / / / / / / / / / / / / V . V . V . V . V . V . V . V . V . V . V . V . W W "\\v ZA±02 A3.1 41.7 40.6 35.3 33.8 32.7 27.0 21.7 18.8 CRUDE P R O T E I N (% OF O V E N DRY W E I G H T ) w \ \ \ \ \ \ \ \ \ \ \ v .v.v.v.w.v.w V//, EPAN BLSP POMU VAPA VAAL PSME GASH TSHE THPL ALSA v \ \ V w \ V w \ \ \ \ \ v.v.v.v.v.w. y / / / //////////////. 16.5 11.1 1Q.9 10.1 9.7 6.8 6.5 5.3 5.2 1.9 D I G E S T I B L E DRY MATTER (% OF OVEN DRY W E I G H T ) A L S A E P A N T H P ' L ' ^ ^ ^ S M E V A P A V A A L '/////////////. 72. 5 71.3 53.5 47.4 47.1 41.9 \ \ \ \ B L S P 39.3 //// T S H E //// 36.9 G A S H 2 8 . 1 . W W P O M U 2 4 . 1 Forage species codes and type designations are as follows: SHRUBS GASH = Gaultheria shallon CONIFERS '////, PSME = Pseudotsuga menziesii LICHEN ALSA = Alectoria sarmentosa FORBS EPAN = Epilobium angustifolium FERNS .WW BLSP = Blechnum spicant !Species not underlined by common l i n e are 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) as determined by analysis of variance and Scheffe's t e s t . VAAL - Vaccinium alaskense THPL = Hiuja plicata POMU = Polystichum nrunitum VAPA = V. parvifolium TSHE = Tsuga heterophylla Shrubs Conifers Forested Forested Cutover c e l l contents = O c e l l u l o s e hemicellulose = l i g n i n = Crude ^ Protein \ D i g e s t i b l e Dry Matter Figure 3-5. Average annual composition of forage types c o l l e c t e d from forested and cutover areas. Values are percent of dry matter. VO oo 99 examined, Epilobium angustifolium, was highest (21.7 ± 2.3 percent) in crude protein content (Table 3.1). 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 l l seasons. Low levels of crude protein in A. sarmentosa are consistent with those measured in several other lichen species (Scotter 1972). In Alectoria jubata, Scotter (1965) meas-ured 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 were compared within forage type several significant (p < 0.05) 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 hetero-phylla 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 al. (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, and between spring and summer in forbs and ferns. Conifers showed l i t t l e 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 in nitrogen content between bud burst and init i a l stages of expansion of P. menziesii shoots noted by Krueger (1967) were not detected in forested areas but were apparent in cutovers. When compared seasonally, crude protein in shrubs and ferns was signifi-cantly higher in forested areas than in cutovers during summer and f a l l -winter periods and significantly higher in 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 Wash-ington, 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 l e v e l s i n species he sampled from s i t e s burned 4 and 14 years p r e v i o u s l y . In the present study, canopies of mature stands v a r i e d as to the degree of openings present, and i n few cases was canopy cl o s u r e complete. This may have co n t r i b u t e d to the l a c k of 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 cutovers. Crude p r o t e i n l e v e l s v a r i e d by season and area of 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). Monthly patterns of v a r i a t i o n i n i n d i v i d u a l species from f o r e s t e d and cutover areas are shown g r a p h i c a l l y i n Figures 3-6 to 3-8. W i t h i n the shrub type, G a u l t h e r i a s h a l l o n from cutovers contained l e s s p r o t e i n i n f a l l - w i n t e r than i n other 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 higher i n s p r i n g than i n the f a l l -w i n t er p e r i o d (Table 3-3). Levels i n s p r i n g and summer were not d i f f e r e n t (p < 0.05). In Vaccinium alaskaense, 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 the f o r e s t . In cutover areas, s p r i n g l e v e l s were higher than i n summer and f a l l - w i n t e r ; the l a t t e r two seasons were not d i f f e r -ent. Levels of 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 the other 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 both f o r e s t e d and cut-over areas. Among c o n i f e r s , p r o t e i n content of Pseudotsuga m e n z i e s i i from f o r e s t e d areas d i d not vary w i t h season but i n cutovers was higher i n s p r i n g than i n f a l l - w i n t e r and summer. S i m i l a r l y , Thuja p l i c a t a d i d not vary s e a s o n a l l y i n p r o t e i n content i n timbered areas but was s i g n i f i -c a n t l y higher i n s p r i n g than i n f a l l - w i n t e r and summer i n cutover areas. Tsuga h e t e r o p h y l l a from cutover areas d i f f e r e d only between s p r i n g and 102 Composition (%) FORESTED 3U — 40 GAULTHERIA SHALLON 30 -20 10 H new growth 50 CUTOVER j riew* g r o w t h VACCINIUM ALASKAENSE • / l \ 50 J 10 J "1—f—I 0 VACCINIUM PARVIFOLIUM J F M A M J J A S O N D 10 i J F M A M J J . A S 0 N D ' - - Time (months) - -FIGURE 3-6. MONTHLY PATTERNS OF VARIATION IN COMPOSITION OF SHRUBS COLLECTED IN FORESTED AND CUTOVER AREAS • A CRUDE PROTEIN - • — - DRY MATTER DIGESTIBILITY * LIGNIN — • HEMICELLULOSE . o CELLULOSE 103 C o m p o s i t i o n (%) 60 FORESTED I 50 40 30 -PSEUDOTSUGA MEN'/.rESTT new growth J new growth 60 -a 50 40 30 20 10 4 TSUGA HETEROPHYLLA 60 -| FORESTED new growth V new growth 50 40 30 20 10 H - Time (months) -FIGURE 3-7. MONTHLY PATTERNS OF VARIATION IN COMPOSITION OF CONIFERS COLLECTED IN FORESTED AND CUTOVER AREAS. — A — CRUDE PROTEIN • LIGNIN - . o HEMICELLULOSE — DRY MATTER DIGESTIBILITY o CELLULOSE ALECTORIA SARMENTOSA EPIL031UM ANOUSTIFOLIUM 100 80 60 40 -20 H FORESTED / \ 100 80-60 CUTOVER J F M A « J J A S 0 N D - - Time (months) J F M A M J J A S O N D FIGURE 3-8, MONTHLY PATTERNS OF VARIATION IN COMPOSITION OF FERNS, FORBS AND LICHENS COLLECTED IN FORESTED AND CUTOVER AREAS, • LIGNIN A CRUDE PROTEIN • o HEMICELLULOSE B DRY MATTER DIGESTIBILITY 0 CELLULOSE 105 f a l l - w i n t e r p e r i o d s . Blechnum s p i c a n t i n cutovers d i f f e r e d between f a l l -w i nter and s p r i n g and between s p r i n g and the other seasons i n f o r e s t e d areas. Polystichum muniturn i n cutovers had higher crude p r o t e i n i n s p r i n g than i n the other seasons i n both cutover and f o r e s t e d areas (Table 3-3). Average annual crude p r o t e i n contents f o r a l l species are compared s t a -t i s t i c a l l y i n Table 3-4. Epilobium a n g u s t i f o l i u m contained s i g n i f i c a n t l y more (16.5 ± 3.7%) and A l e c t o r i a sarmentosa s i g n i f i c a n t l y l e s s (1.9 ± 0.1%) crude p r o t e i n than other species examined. The general trend was s i m i l a r to that observed f o r dry matter content; c l o s e l y r e l a t e d p l a n t s (e.g. Vaccinium spp.) 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) contained s i m i l a r l e v e l s of crude p r o t e i n . Dry Matter D i g e s t i b i l i t y (DDM) Annual patterns of DDM i n v i t r o v a r i e d among forage types and by season (Table 3-1). Results discussed here are those f o r mean DDM since DDM values f o r the i n d i v i d u a l deer c o l l e c t e d each month i n most instances were not s t a t i s t i c a l l y d i f f e r e n t . A l e c t o r i a sarmentosa was the most d i -g e s t i b l e forage (72.5 ± 4.5%) on an annual b a s i s , while ferns had the lowest DDM (31.6 ± 1.8%). On an annual b a s i s , DDM decreased i n the order 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 . A l l types were s i g n i f i c a n t l y d i f f e r e n t from each other (p < 0.05) w i t h the exception of l i c h e n s and f o r b s , which were not d i f f e r e n t . Within-season comparisons of forage types are presented i n Table 3-1. Fewer d i f f e r e n c e s occurred between types i n s p r i n g than i n other seasons, but a number of 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 s occurred each season. The r e l a t i v e ranking of 106 DDM, with lichens highest and ferns lowest remained consistent through al l seasons with one exception. A. sarmentosa was much lower in DDM in spring (48.2 ± 2.3%) than its mean annual DDM (72.5 ± 4.5%). DDM of conifers, shrubs and forbs did not differ significantly between seasons (Table 3-2). 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 somewhat unexpected since DDM was highest in spring or summer in the other types. In the case of A. sarmentosa the low DDM in spring was 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 digested to a much lesser extent during this period. The 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 explain the low DDM and will be discussed further in conjunction with the fibre components. Comparison of annual DDM levels in forage types from forested and 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. This difference also was not significant. Mean DDM 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 in either forested areas or cut-overs 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 in 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. Blechnum spicant differed sig-nificantly in DDM between spring and fall-winter, with highest levels in the latter period in both forested and cutover areas. There were no seasonal differences in DDM 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 statisti-cally significant only in fall-winter for Gaultheria shallon and Vaccinium  parvifolium. An exception was G. shallon which was significantly more digestible in timber in summer. Among conifer species, DDM was generally higher in cutovers than in forest throughout the year as was crude protein (statistical differences are indicated in Table 3-3). DDM of the fern species did not differ signifi-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 were compared on an annual basis (Table 3-4). Alectoria sarmentosa and Epilobium angustifolium were sub-108 s t a n t i a l l y more digestible than a l l other species. As was observed with both dry matter and crude protein content, species of similar structure tended to have similar d i g e s t i b i l i t i e s , with some exceptions as indicated i n Table 3-4. To summarize, the species exhibiting the highest DDM was Alectoria  s a rmento s a,p rob ably the result of i t s containing d i f f e r i n g types of struc-t u r a l carbohydrates (e.g. hemicellulose rather than ce l l u l o s e , Hale 1961) and 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 spring, apparently the result of changes i n the capacity of rumen microbes to digest lichen at this time. Among the forage types, ferns were lowest i n DDM with the lowest seasonal levels occurring when only new growth on act 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 i s the result of high proportions of l i g n i n at this time. Contrary to other forage types, ferns exhibited highest l i g n i n contents i n spring (Table 3-7). Seasonal differences i n DDM did not occur i n conifers and shrubs, probably related to the presence of greater amounts of fibrous structural tissue i n these forage types than i n herbaceous plants, except ferns, which con-t a i n higher than expected levels of f i b r e . Broadly consistent, but nonsignificantly higher levels of DDM occurred i n forage types from cutovers compared to forested areas. Einarsen (1946) also observed that forage quality (protein content) of plants from cut-overs was higher and attributed i t to increased sunlight and nutrient supplies i n slash 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 is digested determines its value to a ruminant. Species which are 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. Results are expressed in Table 3-5 in terms of 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. Both March trials were conducted on plant species in the dormant state. For a l l species but Alectoria sarmentosa an apparent asymptote in the first 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, Table 3-5. Rates of in vitro d i g e s t i b i l i t y of selected forage species. Percent of Maximum Dry Matter D i g e s t i b i l i t y 1 48-Hour Occurring i n : Observed Digest-T r i a l 12 24 36 i b i l i t y 2-Stag Date Species - Area 2 Hours Hours Hours (Actual) Method March 5 Gaultheria shallon - F 76.0" 88.0 100.0 17.3 33.0 Vaocinium alaskaense - F 66.0 89.0 89.0 26.7 34.5 Thuja plioata - F 88.0 88.0 100.0 43.8 52.5 Alectoria sarmentosa - F 25.0 46.0 91.0 60.6 80.0 March 19 Bleohnum spicant - C 56.0 75.0 100.0 33.0 41.5 Vaocinium parvifolium - C 70.0 82.0 97.0 34.8 45.5 Thuja plicata - C 82.0 90.0 94.0 52.5 57.0 Thuja plicata - F 72.0 96.0 96.0 48.0 52.5 June 14 s Vaocinium parvifolium - C 76.0 96.0 100.0 58.1 55.0 V. alaskaense - C 80.0 100.0 100.0 63.1 65.0 Pteridium aqualinum - C 86.0 100.0 100.0 47.3 48.0 Sambuous racemosa - C 83.0 93.0 100.0 75.7 77.5 Pseudotsuga menziesii - C 77.0 100.0 100.0 42.6 37.0 1 In vitro d i g e s t i b i l i t y a f t e r 48 hours incubation i n rumen f l u i d . 2Area of c o l l e c t i o n : F = Forested, C = Cutover. 3In vitro d i g e s t i b i l i t y by T i l l e y and Terry method - 48 hours incubation i n rumen f l u i d , 48 hours incubation i n Acid-pepsin s o l u t i o n . ^Values are means of two r e p l i c a t e samples. 5 P l a n t s c o l l e c t e d i n May, deer c o l l e c t e d i n June. I l l since i t would leave the rumen prior to being fully digested. Person et al. (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 tr 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. Also of interest is the observation that, in June, DDM 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. In March, the two-stage digestion produced con-sistently higher levels of DDM than the 48-hour fermentation. These observations 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. The advantages of the Van Soest system over traditional crude fibre measurement were j discussed earlier, as were components of fibre. To summarize: Neutral-detergent fibre (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 al 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 collected from forested (F) and cutover (C) areas i n d i f f e r e n t seasons. Comparisons are made between forage types for each season and annually. Neutral-Detergent C e l l Contents Fibre Season Forage Type F C F+C F of oven dry C F+C F C F+C Spring Shrubs 6 6 12 253.3 a (13.8) 63. 2 a ( 7.5) 58.3 a (11.8) 46.7 a (13.8) 36.7 a ( 7.5) 41.7 a (11.8) Conifer 6 6 12 58. 8 a ( 6.6) 65.7 a • ( 8.3) 62. 2 a ( 8.0) 41.2 a ( 6.6) 34. 3 a ( 8.3) 37.8 a ( 8.0) Lichen 2 - 2 83. 0 b ( 1.7) - - 17.0 b ( 1.7) - -Forbs - 2 2 - 87. 2 b ( 6.4) - - 12.8 b ( 6.4) -Ferns 4 A 8 44. 7 a (15.5) 5 0 . l c ( 9.0) 47.4 C (12.1) 55. 2 a (15.5) 49.9° ( 9.0) 52. 6 C (12.1) Summer Shrubs 8 8 16 45.9 a ( 6.6) 56.3 a ( 4.9) 51. l a ( 7.8) 54. l a ( 6.6) 43.7 a ( 4.9) 48.9 a ( 7.8) Conifer 7 7 14 60. 5 b ( 6.7) 61.5 b ( 4.2) 61.0 b ( 5.4) 39.5 b ( 6.7) 38.5 a ( 4.2) 39.0 b ( 5.4) Lichen 3 - 3 77.2° ( 8.3) - - 22.8 C ( 8.3) - -Forbs - 2 2 - 73.8 C ( 8.4) - - 26.2 b ( 8.4) -Ferns 4 4 8 33.3 d ( 4.6) 44.5 d (13.0) 38.9 d (10.8) 66.7 d ( A.6) 55.5 C (13.0) 61. l d (10.8) I Table 3-6. continued. Season -Forage Type F a l l - W i n t e r Shrubs Conifer Lichen Forbs Ferns 17 18 10 18 18 10 F+C 35 36 20 C e l l Contents (Percent o f oven dry weight) F C F+C 45.1" ( 5.4) 58. 6 b ( 4.5) c 75.7 ( 6.3) 38.1" ( 9.3) ad 50.2 ( 7.7) 61.0 C ( 4.0) 55.8 ( -.) 47.3 d (10.5) abd 47.7 ( 7.1) 59. 8 b ( 4.4) 42.7 (10.7) Neutral-Detergent F i b r e 54.9" ( 5.4) 41.4 b ( 4.5) 24.3° ( 6.3) 61.9" ( 9.3) ad 49.7 ( 7.7) 39.0 C ( 4.0) 44.2 ( - ) 52.7 d (10.5) abd F+C 52.3" ( 7.1). 40. 2 B ( 4.4) 57.3" (10.7) A l l - y e a r Shrubs .34 32 63 46.9 3 54 .2 a 50. 6 a 5 3 . l a 45.8 a . 4 9 . 4 A ( 8.2) ( 8 .5) ( 9.1) ( 8.2) ( 8.5) ( 9.1) Conifer 34 31 62 59. l b 62, .0 b 60.5 b 40.9 b 38. 0 b 39.4 b ( 5 . 3 ) ( 5. 2) ( 5.4) ( 5.3) ( 5.2) ( 5 . 4 ) Lichen 12 1 11 77.4 C 77.4 C 22.6° - _ 22.6 C ( 6.5) ( 6.5) ( 6.5) ( 6.5) Forbs - • 5 , 5 — 75. ,5°' 75.5 C _ 24.5 C 24. 5° (14. •Q) (14.0) (14.0) (14.0) Ferns 20 . 18 36 38.5 d . 47. .3d'.-- 42.9 d 61.5 d 52.7 d 57. l d (10.4) (10. 3) ( U . l ) (10.4) (10.3) (11.1) '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 only about 50 percent 2 of the samples wh i l e other analyses treated a l l samples. 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) are not d i f f e r e n t at p < 0.05 l e v e l as determined by a n a l y s i s of vari a n c e and Scheffe s t e s t . Table 3-7. S t a t i s t i c a l comparisons of 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 content 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 . Ac id-Detergent Acid-Detergent N ijjj>re L i g n i n C e l l u l o s e H e m i c e l l u l o s e Season -Forage Type F C F+C F 1 C F+C — (percent of ov F C en dry F+C weight) -F C F+C F C F+C S p r i n g Shrubs 6 6 12 2 41 .1 a (10.3) 32 ( 6 . 0 a • 3) 36. 5 a ( 9.5) 16.8 a ( 3.6) 14.4 a ( 2.9) 15. 6 3 ( 3.4) 24. 3 a (10.2) 17 ( 4 ^abc • 2) 20 ( 8 . 9 a b • 2) 5.6 a (11.9) 4 ( 8 .8 a • 0) 5 ( 9 . 2 a • 7) C o n i f e r 6 6 12 35. 5 a (10.2) 31 (13 . 9 a .8) 33.7 a ( 9.7) 20.9 a b ( 2.0) 15.5 a ( 3.2) 18. 2 a ( 3.8) 14. 6 b ( 2.2) 16 (12 , abc .4 • 6) 15 ( 8 . 5 a C .7) 5.7 a ( 3.4) 2 (11 . 5 a .6) 4 ( 8 . l a • 3) L i c h e n 2 - 2 4.0 b ( - ) - 3.0° ( 1.4) - - i . o c ( 1.4) 13.0 a ( 1.7) Forbs - 2 2 - 11 ( 4 . l b .4) - - 6.0 b ( 2.9) - - 5 ( 1 . l b • 5) - 1 ( 2 .6 a • 0) Ferns 4 4 8 52. 3C (2 .8 ) 49 ( 8, .6° .9) 51. 0C ( 6.3) 24. 9 b ( 9.3) 21.7° ( 3.7) 23.3° ( 6.8) 27.3 a ( 8.8) 27 ( 9 .9 C .7) 27, ( 8, ,6 b .6) 2.9 a (16.4) 0 ( 4 .25 a .2) 1. (11. .6 a .1) Summer Shrubs 8 8 16 41.4 a ( 8.4) 34. (11. ,7 a .6) 38. l a (10.4) 22. 3 a ( 4.8) 15. 3 a ( 3.1) 18.8 a ( 5.3) 19. 2 a ( 9.1) 19 (11. . 5 a .8) 19. (10. ,3 a .2) 12. 7 a (11.6) 8 ( 9, .9 a • 8) 10. (10. ,8 a .6) C o n i f e r 7 7 14 34.4 a ( 5.4) 32. ( 7. ,o a .5) 33. 2 a ( 6.4) 22. 6 a ( 2.4) 19. 2 a ( 4.5) 20.9 a ( 3.9) 11.9 a ( 5.6) 12. ( 5, .8 a .9) 12. ( 5. ,3 b 6) 5.0 a ( 6.4) 6, ( 7, .6 a • 0) 5. ( 6. 8 a 5) Lichen 3 - 3 15. 5 b (10.6) - 3.3 b ( 0.2) - .. - 12. 2 a (10.8) 7.3 a (18.8) Forbs - 2 2 - 14. ( 4. ,9 b • 1.) - - 3.4 b ( 1.6) - - 11. ( 2. .5 a .5) - 11. (12. .3 a .6) Ferns 4 4 8 64. 6C (11.8) 52. (10. 1C 3) 58. 4C (12.2) 25.8 a ( 3.4) 19.7 a (10.1) 22.7 3 ( 7.7) 38.8 b ( 9.4) 32. ( 4. ,4 b .6) 35. ( 7. b C 7) 2.1 a (16.3) .3. (10. ,4 a • 2) 2. (12. 7 a 6) Table 3-7. continued. Season -Forage Type F Ac id-Detergent Fibre Acid-Detergent Lignin  C e l l u l o s e Hemicellulose F+C F+C (percent of oven dry weight) F C F+C F F+C F+C Fall-Winter Shrubs 17 Conifer 18 Lichen 6 Forbs Ferns 10 18 18 35 36 10 20 42. 3 a 38.9 a 40 .6 a 19. l a 17. 6 a 18 .4 a , 26.3 a 22 .2 a ' 24 aD .2 12 .6 a 10 . 8 a : 11 .7 a •( 5.5) ( 7.1) ( 6, .5)'.' ( 3,2) ( 4. 7) ( 3 .9) ( 3.6) ( 4 .8) ( 4 .5) < . . * •4) . ( 5 ( 4 • 8) 34. 3 b 32. 3 b 33, .3 b 2 0 . l a 15. l a 17 .6 a 15.5 b 20 . 9 a 18 .2 a 7 . l b 6 ; 6 B 6 . 9 b ( 2 . 6 ) ( 6.8) ( 5. 2) ( 2.1) ( 4. 7) ( 4, • 4 > ( 1.1) (15 .6) (10 .9) ( 3 • 8) '( 5 • 1 > - ( 4 .4) 5.9 C - 1 . 6 B 2.7 C 18 . 4 ° ( 5 . 6 ) ( 0.2) ( 0.3) ( 8 . • 1) - 21.3 b — 4. 8 a _ 16, ,5 a 22 . 9 C ( - ) ( -• ) ( -- ) ( -- ) 47.8 d 42. 6 a 45.3 d 17.5 a 19. 5 a 18. ,5a 32.6 d 28. , o a 30 3bd 13. ^ ac i d , j ab 11. , 9 a ( 5.2) (10.4) ( 8. 3) ( 7.6) ( 9. 2) ( 7. 9) ( 5.0) ( 6. 4) ( 5 .9) ( 5, • 9 > ( 6, .4) ( 6. 3) 41. 9 a 36. 6 a 39. 2 a 19.7 a b 15. 7 a 17. 7ac 22.8 a 19. 7 a 21 .3 a 11. .3 a 9. ,2a 10. 2 a ( 7.1) ( 8.5) ( 8. 2) ( 4.5) ( 3. 7) ( 4 . 5) ( 8 . 4 ) ( 8. 1) ( 8 .3) ( 8. 6) ( 7. • 2) ( 7. 9) 34. 5 b 32.2 b 33. 3 b 21.3 a C 16.7 a C 19. 0 a 13. 9 b 16.5 a b 15 .2 b 6. ,bd 5. 8 a 6. l b ( 3,4) ( 8.3) ( 6 . 4) ( 2.3) ( 4. 4) ( 4 . 2) ( 3.8) (11. 6) ( 8 .6) ( 4. 4) ( 7. 0) ( 5.8) A l l - y e a r Shrubs 34 Conifer 34 Lichen Forbs Ferns 12 20 32 31 63 62 11 18 36 8.2 ( 7.8) •52. 3" ( 9.2) i 4 . r ( 5.1) 46.3 d (10.4) 8.21" ( 7.8) 14.7° ( 5.1) 49.4 d (10.2) 2, ( 1. 7 0) 22.8 ( 7.6) be 4.8° ( 2.1) 20.3° ( 7.4) 2.7 U ( 1.0) 4.8 b (2.1) 21.5° ( 7.5) 6.31" ( 8.4) 32.9 ( 8.7) 6.3 ( 8.4) ce 14.4* (11.4) 14.4 (11.4) ade 9.9" ( 5.1) 29.4 C ( 6.9) be 9.9 ( 5.1) 31. 2 d ( 7.9) 3.0 ( 8.9) cd 9. (10. 6. ( 7. 8" S) 4 a 9) ;•. 9.8 (10.8) abef 5.3 ( 8.3) c d f !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 , since ADL and c e l l u l o s e were determined on only about 50 percent of the samples while other analyses treated a l l samples. Values i n a column with a common superscript l e t t e r (a, b, c) are not d i f f e r e n t at p < 0.05 l e v e l as determined by analysis of variance and Scheffe's test. 117 When compared seasonally, the woody types, shrubs and conifers did not differ from each other during spring in 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 signifi-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 in 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 in fibre levels in 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 in a l l forage types collected in cutovers than in forested areas and NDF was thus con-sistently 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 collected from forested (F) and cutover (C) areas in different seasons. Comparisons are made between seasons and areas of collection for each forage type. i Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) >? C F+C F _C F+C F C F+C F C Shrubs Spring 6 6 12 a53. ,32 a63. .3 a58. .3 a46. .7 a36, .8 a41 .7 341, .1 a32. .0 a36, .5 ( 6) ( 6) (12) (13. .8) ( 7. 5) (11. .8) (13. .8) ( 7. 5) (11 • 8) (10. • 3) ( 6. • 3) ( 9. 5) Summer 8 8 16 3 b45. 9 356. . 3++3 b51. ,1 a b54. .1++ 343. .7 b48 .9 a41. .4 a34. .8 a38. .1 ( 8) ( 8) (16) ( 6. 6) ( 4. ,9) ( 7. .3) ( 6. 6) ( 4. 9) ( 7 • 8) ( 8. 4) (11. .7) (10, .4) Fall-Winter 17 18 35 b45. 1 b50. ,3++ b47. J b54. ,9++ b49. .7 b 5 2 .3 a42. .3++ a38. .9 a40. .6 ( 5) ( 6) (11) ( 5. •4) ( 7. 7) ( 7. ,1) ( 5. ,4) ( 7. 7) ( 7 .1) ( 5. 5) ( 7. • 1) ( 6, .5) Annual 31 32 63 46. 9 54. ,2++ 50. ,6 53. ,1++ 45. ,8 49 .4 41. .9++ 36. ,6 39. ,2 (20) (20) (40) ( 8. 2) ( 8. 6) ( 9. 1) ( 8. 2) ( 8. 6) ( 9 • 1) ( 7. ,1) ( 8. 5) ( 8. •2) Ac id-De tergent Lignin Cellulose Hemicellulose ( Percent of oven dry weight ) I 0 F+C F C F+C F C F+C Shrubs, continued Spring a16. .8 a!4. ,4 a l 5 . .6 a24. .3 al7.5 a20, .9 a5, .6 a4, .8 a5.2 ( 3. 7) ( 2. <)) ( 3. 4) (10, .2) ( 4.2) ( 8, .1) (11. .9) ( 8 .0) ( 9.7) Summer b22. ,3++ a15. , 3 a18. ,8 a19. ,2 a19.5 a19, .3 a12, .7 a8, .9 a b10.8 ( 4. 8) ( 3. ,1) ( 5. 3) ( 9. 1) (11.8) (10, .2) (11 , • 6) ( 9, .9) (10.6) Fall-Winter a b19. ,1 a17. .6 a l 8 . .4 a26. .3+ a22.2 a24. .2 a i 2 . .6+ a i o . .8 b11.7 ( 3. 2) ( 4. ,7) ( 3. 9) ( 3. • 6) ( 4.8) ( 4, .5) ( 4, • 4) ( 5. 1) ( 4.8) Annual 19. .7++ 15. ,7 17. 7 22. ,8 19.7 21. .3 11. ,2 9. .2 10.2 ( 4. ,5) ( 3. ,7) ( 4. •5) ( 8. 4) ( 8.1) ( 8. 3) ( 8. 6) ( 7. 2) ( 7.9) Table 3-8. continued.. Neutral-Detergent Acid-Detergent C e l l Contents Fibre Fibre ( Percent of oven dry weight ) F C F+C F C F+C F C F+C F C F+C Conifers Spring 6 6 12 a58. .8 365.7+ a62.2 S41.2+ a34.3 a37. .8 a35, .5 a31. .9 a33 .7 ( 6) ( 6) (12) ( 6. 6) ( 8.3) ( 8.0) ( 6.6) ( 8.3) ( 8, • 0) ( 3. • 2) (13, • 8) ( 9 • 7) Summer 7 7 14 a60. ,5 a61.5 a61.0 a39.5 a38.5 a39. .0 a34. .4 a32. .0 a33 .2 ( 7) ( 7) (14) ( 6. 7) ( 4.2) ( 5.4) ( 6.7) ( 4.2) ( 5. • 4) ( 5. 4) ( 7. 5) ( 6 • 4) Fall-Winter 18 18 36 a58. .6 a61.0++ a59.8 a41.4++ a39.0 a40. .2 a34. .3 a32. .3 a33 .3 ( 6) ( 6) (12) ( 4. 5) ( 4.0) ( 4.4) ( 4.5) ( 4.0) ( 4. ,4) ( 2. 6) ( 6. 8) ( 5 • 2) Annual 31 31 62 59. 1 62.0++ 60.5 40.9++ 38.0 39. ,4 34. ,5 32. .2 33 .4 (19) (19) (38) ( 5. 3) ( 5.2) ( 5.4) ( 5.3) ( 5.2) ( 5. 4) ( 3. 4) ( 8. 3) ( 5 .3) Acid-Detergent Li g n i n Cellulose Hemicellulose  ( Percent of oven dry weight ) I C F+C F C F+C F C F+C Conifers, continued Spring a20. 9++ a15. 5 a b18.2 a14. .6 H16.4 a l 5 . .5 a5 .7 a2, .5 a4.1 ( 2. 0) ( 3. 2) ( 3.8) ( 2. 3) . (12.6) ( 8. 7) ( 3, .4) (11 .6) ( 8.3) Summer a22. 6+ a19. 2 a20.9 a i l . .9 a l 2 . 8 312. .3 35. .0 a6, .6 a5.8 ( 2. 4) ( 4. 5) ( 3.9) ( 5. 6) ( 5.9) ( 5. 6) ( 6, .4) ( 7. 0) ( 6.5) Fall-Winter. a20. 2++ a15. .1 b17.6 a15. ,5 a20.9 a18. ,2 a7. .1 a6. .6 a6.9 ( 2. 1) ( 4. 8) ( 4.4) ( 1. • 1) (15.6) (10. .9) ( 3. 8) ( 5. 1) ( 4.4) Annual 21. 3++ 16. 7 19.0 13. ,9 16.5 15. 2 6. .4 5. .8 6.1 ( 2. 3) ( 4. 4) ( 4.2) ( 3. 8) (11.6) ( 8. 6) ( 4. 4) ( 7. • 1) ( 5.8) I— I—1 vO Table 3-8. continued. / Neutral-Detergent Acid-Detergent C e l l Contents Fibre Fibre ( Percent of oven dry weight ) . F + C F C F+C F C F+C F C F+C Lichens Spring Summer Annual 2 ( 2) a83.0 ( 1.7) a l 7 . 0 ( 1.7) a4.0 ( - ) 3 ( 3) a77.2 ( 8.3) a22.8 ( 8.3) a15.5 (10.6) 6 ( 6) a75.7 ( 6.3) a24.3 ( 6.3) a5.9 ( 5.6) 11 ( 7) 77.5 ( 6.5) 22.6 ( 6.5) 8.2 ( 7.8) Lichens, continued Acid-Detergent Lignin  F+C Cellulose -( Percent of oven dry weight )-F C F+C Hemicellulose F+C Spring 33.0 ai.o a13, .0 ( 1.4) ( 1.4) ( 1, .7) Summer a3.3 a12.2 a7, .3 ( 0.2) (11.0) (18, .8) Fall-Winter 31.6 a2.7 S18. ,4 •( 0.2) ( 0.3) ( 8. ,1) Annual 2.7 6.3 14. ,4 ( 1.0) ( 8.4) (11. 4) Table 3-8. continued. Neutral-Detergent Acid-Detergent Ce l l Contents Fibre Fibre ( Percent of oven dry weight ) :  F C F+C F C F+C . F C F+C F C F+C Forbs Spring 2 a87.2 al2.8 aU.2 ( 2) ( 6.4) ( 6.4) ( 4.4) Summer 2 a73.8 326.2 a l 4 . 9 ( 2) ( 8.5) ( 8.5) ( 4.1) Fall-Winter 1 a55.8 a44.2 a21.3 ( 1) ( - ) ( - ) ( - ) Annual 5 75.6 24.5 14.7 ( 5) (14.0) (14.0) ( 5.1) Ac id-Detergent Lignin Cellulose Hemicellulose ( Percent of oven dry weight ) F C F+C F C F+C I- C F+C Forbs, continued Spring a6.1 a5.1 a1.7 ( 2.9) ( 1.5) ( 2.1) Summer a3.4 a b11.5 a l l . 3 ( 1.6) ( 2.5) (12,6) Fall-Winter a4.9 b!6.5 a22.9 ( - ) ( - ) ( - ) Annual 4.8 9.9 9.8 ( 2.1) ( 5.1) (10.9) Table 3-8. continued. Neutral-Detergent Acid-Detergent N^ C e l l Contents F i b r e F i b r e : ( Percent of oven dry weight ) F C F+C F C F+C F C F+C F . C F+C Ferns Spring 4 4 8 a44. 8 a50.1 a47. ,4 a55, ,3 a50. .0 a52. .6 a52, .3 a49. .6 a b 5 1 . .0 ( 4) ( 4) ( 8) (15. 5) ( 9.0) (12, .1) (15. • 5) ( 9. • 0) (12. .1) ( 2. • 8) ( 8. 9) ( 6, .3) Summer 4 4 8 a33. 3 a44.5+ a38. .9 a66. .7+ a55. .5 a61. ,1 b64, .6 a52. .1 a58. .4 ( 4) ( 4) ( 8) ( 4. 6) (13.0) (10, • 8) ( 4, .6) (13. .0) (10. ,8) (11, .8) (10. .3) (12. .2) F a l l - W i n t e r 11 10 21 a38. 1 a47.3++ a42. ,7 a61. ,9++ a52. ,7 a57. .3 a47, .8+ a42. ,6 b45, .3 ( 4) ( 4) ( 8) ( 9. 3) (10.5) (10. .7) ( 9. 3) (10. .5) (10. ,7) ( 5, .2) (10. ,4) ( 8. 3) Annual 18 18 36 38. 5 47.3++ 42. ,9 61. ,5++ 52. .7 57. ,1 52. ,3 46. .3 49, .4 (12) (12) (24) (10. 4) (10.3) (11. .1) (10. • 4) (10. .3) (11. .1)' ( 9. ,2) (10. ,4) (10. .1) Acid-Detergent L i g n i n C e l l u l o s e Hemicellulose ( Percent of oven dry weight ) • I C F+C F C F+C _F C • F+C Ferns, continued Spring a25. 0 a 2 1 . 7 a23. 3 a27.4 a27.9 a27, .6 3 3 . 0 ao. 2 . a l . .6 ( 9. 3) ( 3. 7) ( 6. 8) ( 8.8) ( 9.7) ( 8, .6) (16. 4) ( 4. 2) (11, .2) Summer a25. 7 a l 9 . 7 a22. 8 a38.8 332.4 b35, .6 a 2 . 1 a b 3 . 4 . a 2 , .7 ( 3. 4) (10. 1) ( 7 . 7) ( 9.4) ( 4.6) ( 7, .7) (16. 3) (10. 2) (12, .6) F a l l - W i n t e r 317. 6 319. 5 a 18 . 5 a32.6 a28.0 3 b 3 0 , ,3 a 13 . 7 b10. 1 b l l . ,9 ( 7. 7) ( 9. 2) ( 7. 9) ( 5.0) ( 6.4) ( 5. • 9) ( 5. 9) ( 6. 4) . ( 6. .3) Annual 22. 8 20. 3 21. 5 32.9 29.5 31, ,2 3. 0 6. 4 5. 3 ( 7. 6) ( 7. 5) ( 7. 5) ( 8.7) ( 6.9) ( 7. 9) ( 8. 9) ( 7 . 9) ( 8. 3) lN 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 only about 50 percent of the samples whi l e other analyses treated a l l samples. 2Values 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 l e v e l as determined by a n a l y s i s of va r i a n c e and Scheffe'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 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 £ 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 beside the measure having the greater value, 123 protein, sugars and starches were higher in cutovers as a result of in-creased sunlight, better growing conditions and perhaps increased avail-ability 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 its evergreen habit. All seasonal G. shallon samples included leaf tissue, which is usually lower in NDF than twig tissue (Short et al. 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 mate-rial 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 its 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). Cell contents were highest during spring and lowest in fall-winter. 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 collected i n forested (F) and cutover (C) areas at different seasons. Comparisons are made between seasons and areas of co l l e c t i o n . Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) F C F C F+C . F C F+C F C F+C Shrubs Gaultheria shallon Spring 2 2 a64.0' a66.7 a65.4 a36.0 a33.3 a34. 6 a36.5 a32. .8 a34.6 (10.4) ( 7.2) ( 7.5) (10.4) ( 7.2) ( 7. 5) ( 4.3) ( 6. 9) ( 5.2) Summer 3 3 b47.1 b56.2+ 2 b51.7 b52.9+ a43.8 b48. 3 a39.3 a35. .1 a37.2 ( 8.1) ( 7.5) ( 8.6) ( 8.1) ( 7.5) ( 8. 6) ( 4.4) ( 9. 0) ( 6.8) Fall-Winter 6 6 b50.1 b56.8++ b53.4 b49.9++ a43.2 b46. 6 a40.8+ a37. ,3 a39.1 ( 3.0) ( 5.6) ( 5.5) ( 3.0) ( 5.8) ( 5. 5) ( 2.6) ( 3. • 4) ( 3.4) Annual 11 11 51.8 58.4++ 55.1 48.2++ 41.6 44. 9 39.6+ 35. ,9 37.8 ( 8.2) ' ( 7.0) ( 8.2) ( 8.2) ( 7.0) ( 8. 2) ( 3.5) ( 5. 5) ( 4.9) Acid-Detergent Lignin Cellulose Hemicellulose  . ( Percent of oven dry weight )-F C F+C F C F+C F C F+C Shrubs Gaulthevia shallon, (continued) Spring a l 6 . 0 a16. .1 a l 6 . 0 a20. 5++ a16.7 a b18. 6 a-0.5 a0.5 a b o . .5 ( 1.0) ( 3. 6) ( 2. 1) ( 3. 3) ( 3.3) ( 3. 5) (6.1) ( 0.4) ( 3. 6) Summer a23.1 318. ;0 a20. 6 316. 2 a l 7 . 0 a16. 6 b13.6 b8.8 a l l . .1 (5.5) ( 1. • 9) ( 4. 6) ( 1. 0) ( 7.1) ( 4. 5) ( 3.7) ( 1.6) ( 3. • 6) Fall-Winter al7.7 a!7. , 1 317. 4 a26. 3 a20.2 b23. 2 b9.1 a b5.9 b7. ,5 ( 0.4) ( 3. 1) ( 1. 9) ( 0. 8) ( 2.4) ( 3. 8) ( 3.3) ( 4.3) ( 4. 0) Annual 19.5 17. ,2 18. 4 20. 3 17.8 19. 1 8.6 5.7 7. .1 (4.7) ( 2. • 4) ( 3. 8) ( 4. 8) ( 4.7) ( 4. 7) ( 6.0) ( 4.3) ( 5. 3) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) F C F C F+C F C F+C F C F+C Shrubs Vaocinium alaskaense Spring 2 2 a45. 2 359. ,4 a52. 3 a 54. .8 a40. .6 a47. .7 a51. .5 a32. .0 341. ,7 (18. 8) ( 6. 0) (14. 0) (18. .8) ( 6. 0) (14, .0) ( 2. 2) (11. .7) (.1.3. 2) Summer 3 3 . a41. 7 a58. 0 a49. 8 a58. .3 a42. .0 a50. .2 b37. .2 a33. .3 a35, .2 ( 6. 0) ( 2. 9) ( 9. 9) ( 6. 0) •( 2. • 9) ( 9. 9) ( 0. • 6) (11. .5) ( 7, • 6) Fall-Winter 6 6 a42. 5 b44. ,9 a43. 7 a57. ,5 b55. .1 a56. .3 a b43. .5 a41. .7 a42, .6 ( 2. 9) ( 7. 3) ( 5. 5) ( 2. 9) ( 7. 3) ( 5. 5) ( 6. 2) ( 9. 3) ( 7. 6) Annual 11 11 42. 8 51. .1++ 46. 9 57. ,2+ 48. ,9 53. ,1 43. .2 37. .6 40. ,4 ( 7. 0) ( 9. 1) ( 9. 0) ( 7. ,0) ( 9. ,1) ( 9. 0) ( 6. 7) (10. .3) ( 8. 9) Acid-Detergent Lignin Cellulose Hemicellulose  ( Percent of oven dry weight ) F C F+C F C F+C F C F+C Shrubs Vaocinium alaskaense, (continued) Spring 316. 7 a l 5 . .0 a l 5 . .8 a34. ,8 a l 7 . 1 a25, .9 a3. .3 a8. .6 35. .9 ( 6. 7) ( 3. 8) ( 4. 6) ( 8. 9) ( 7. 9) (12. .3) (21. .0) ( 5. • 7) (12. .9) Summer a23. 7 a l 4 . , 9 n i 9 . , 3 a13. ,5 a18. 4 a l 5 . .9 a21. .1 38, .7 a l 4 . .9 ( 4. 4) ( 2. 0) ( 5. 7) ( 5. • 0) (13. 6) ( 9. 5) ( 6. 6) (13. • 2) (11. • 5) Fa 11-W i nter a20. 4 a l 9 . , 6 U20. .0 a24. . 5 a22. 9 a23. .7 a l 4 . ,0 313. .4 313. .7 ( 5. 6) ( 8, .1) ( 5. 7) ( 5. 2) ( 5. 9) ( 4, .6) ( 3. • 9) ( 4. 1) ( 3. 8) Annual 20. 8 .16. . 3 .1.8. ,5 22. .1 19. 3 46. .9 14. ,0 11. ,3 12. .6 ( 5. 4) ( 4. 5) ( 5. • 3) (10. .9) ( 9. 2) ( 9. 0) ( 9. 9) ( 7. 3) ( 8. 6) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) - F C F C F+C F C F+C F C F+C Shrubs V. parvifolium Spring 2 2 a50. 7 363. 6 a57, .1 a49, .4 a36. 4 a42 .9 a35, .4 a31, .1 a33, .2 (10. 7) (11. 7) (11. .8) (10, .7) (11. 7) (11, • 8) (13, .7) ( 3, .1) ( 8, .5) Summer 2 2 350. 4 a b 5 4 . 1 a b52. .2 a49, .7 a b 4 6 . 0 a b47, .8 a51. .0 a36. .5 a43, .7 ( o. 6) ( 4. 5) ( 3. 4) ( o. .6) ( 4. 5) ( 3. 4) (14. .1) (22. .6) (17. • 5) Fall-Winter 5 6 aA2. 0 b49. 1+ b45. ,9 a58. .0+ b50. 9 b54. .1 a42. .6+ a37. .7 a40. ,1 ' ( 5. 9) ( 5. 4) ( 6. 5) ( 5. • 9) ( 5. 4) ( 6. 5) ( 7. 4) ( 7. ,8) ( 7. 7) Annual 9 10 45. 8 53. 0+ 49. ,6 54. ,2 47. 0 50. .4 42. ,8 36. .1 39. ,5 ( 7. 2) ( 8. 3) ( 8. • 4) ( 7. ,2) ( 8. 3) ( 8. 4) (10. .0) ( 9. 9) (10. ,3) Acid-Detergent L i g n i n Cellulose Hemicellulose ( Percent of oven dry weight ) IT C F+C F C F+C F C Shrubs V. parvifolium, (continued) Spring a17. .8 a l 2 . , 3 a15, .0 a17. 6 a18 .8 a18. 2 a b14, .0 a5, .3 a9, .6 ( 4. 2) ( o. • 2) ( 4, .0) ( 9. 5) ( 2 .9) ( 5. 8) ( 3. 0) (14, • 9) (10, .1) Summer a18. ,9 a i l . .8 a15. .3 a32. 1 a24 .7 a28. 4 a l . .4 a9, .5 a4. .1 ( 5. 7) ( 1. 8) ( 5, .4) ( 8. 5) (20 .8) (13. 6) (14. .8) (18, .1) (14. .9) Fall-Winter 319. ,3 a l 6 . 3 a l 7 . ,7 a28. 1 323 .5 a25. 8 b15. .1 a13. .2 a i 4 , .1 ( 3. ,7) ( 4. 9) ( 4. • 0) ( 4. 8) ( 7. • 8) ( 5. 9) ( 3. 8) ( 2. 8) ( 3. 3) Annual 18. ,6 13. 4 16. ,0 25. 9 22 .4 24. 1 11. ,2 10. .9 11. .0 ( 3. 6) ( 3. •2). ( 4. 3) ( 9. 0) (10. • 4) ( 9. 5) ( 9. 3) ( 8. • 7) ( 8. 8) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre  ( Percent of oven dry weight ) F C F C F+C F C F+C F C F+C Conifers Pseudotsuga menziesii Spring 2 2 a57.6 a67. ,9 a62. J a42.4 a32. ,1 a37.2 a36. ,0 a27. ,2 a31. .6 ( 1.8) ( 7. 1) ( 7. 3) ( 1.8) ( 7. 1) ( 7.3) ( 1. 5) ( 5. 0) ( 5. 9) Summer 2 2 359.4 a b62. ,3 a60. ,8 a40.7 a37. .7 339.2 a35. ,9 a25. .1 a30. .4 (10.6) ( 3. .8) ( 6. .7) (10.6) . ( 3. .8) ( 6.7) ( 1. 3) ( 5. 0) ( 6, .9) Fall-Winter 6 6 a55.4 b60. .4++ a57. .9 a44.6++ a39. ,6 a42.1 a34. .5++ a29. .5 a32, .0 ( 3.0) ( 3. .9) ( 4. 2) ( 3.0) ( 3. 9) ( 4.2) ( 1. 5) ( 1. 3) ( 2. 9) Annual 10 10 56.6 62. .3++ 59. .5 43.4++ 37. .7 40.6 35. ,1++ 28, .2 31, .6 ( 4.5) ( 5. 0) ( 5. 5) ( 4.5) ( 5. 0) ( 5.5) ( 1. 5) ( 3, .2) ( 4. 3) Acid-Detergent Lignin Cellulose Hemicellulose  ( Percent of oven dry weight ) F C F+C F C F+C F C F+C Conifers Pseudotsuga menziesii, (continued) Spring a21.3 a15.8 a18. ,5 a14.7 a11.3 a13.0 a6. ,5 a4, .9 a5. .7 ( 0.4) ( 2.7) ( 3. 5) ( 1.9) ( 2.4) ( 2.6) ( o. .4) ( 2. 1) ( 1. 5) Summer a b20.6 a14.6 a17. .6 a15.3 a10.4 a12.8 a4. .8 b12. .7 a8. ,7 ( 0.5) ( 0.2) ( 3. 4) ( 1.8) ( 4.8) ( 4.1) ( 9. 3) ( 1. 2) •( 7. .0) Fall-Winter b19.5+ a16.1 a l 7 . .8 a16.5+ a13.0 a14.7 aio. .1 abio, .1 aio. .1 ( 0.8) ( 0.8) ( 2. 0) ( 0.7) .. ( 0.03) ( 2.0) ( 2, .3) ( 4, .0) ( 3. 1) Annual 20.4 15.5 18. .0 15.5+ 11.6 13.5 8, .3 9, .6 8. .9 ( 0.9) ( 1.4) ( 2. 8) ( 1.4) ( 2.6) ( 2.9) ( 4, .2) ( 4, .1) ( 4, .1) Table 3-9. continued. Neutral-Detergent Acid-Detergent C e l l Contents - Fibre Fibre ( Percent of oven dry weight ) — C - F+C F C F+C Conifers Thuja plicata Spring 2 2 353. . 3 a58. .1 a55, .7 a46. 7 a4! .9 a44 .3 338 .4 a45 .5 a41, .9 ( 7, .9) ( b. 4) ( 6. • 5) ( 7. 9) ( 6. 4) ( 6. • 5) ( 3. • 4) (17. • 1) (10. .9) Summer 3 3 3 b57. \l a58. .8 a b58. .2 a b42. 4 a41. .2 3 b41, .8 b33. .2 b32, .9 b33, .0 ( 2. ,4) ( 3. 1) ( 2. • 6) ( 2. 4) ( 3. 1) ( 2. 6) ( 0. 3) ( 0. 9) ( o. .6) Fall-Winter 6 6 b60. ,9 a61. ,7 b61. ,3 b39. 1 a38. .3 b38. .7 a b35. .4+ b32'. .7 b34. .1 ( 3. •1) ( 3. 1) ( 3. ,0) ( 3. 1) ( 3. • l) ( 3. 0) ( 2. 8) ( 1. • 7) ( 2. ,6) Annual 11 11 58. ,6 60. 2+ 59. .4 41. 4+ 39. ,8 40. .6 35. ,3 35. ,1 35. .2 ( 4. •6) ( 3. 7) ( 4. 2) ( 4. 6) ( 3. 7) ( 4. • 2) ( 2. 9) ( 7. 6) ( 5. 6) Acid-Detergent Lignin Cellulose Hemicellulose ( Percent of oven dry weight ) F+C F C F+C F C Conifers Thuja plicata, (continued) Spring a22.2+ a16. 8 319. , 5 a16.2 a28, .7 a22, .4 3 b8, .4 a-3 .6 a2. ,4 ( 1.1) ( 1.0) ( 3. 2) ( 2.3) (18. .0) (12, .7) ( 4. 5) (23 • 5) (15. .5) Summer a23.8+ h22.8 a23. 3 a9.4 a i o . .2 V .7 a9. .2 a8, .3 a8. .7 ( 3.2) ( 3.3) ( 3. 0) ( 2.9) ( 2. 4) ( 2. 4) ( 2. 2) ( 2, .6) ( 2. 2) Fall-Winter a21.5 a l 7 . 5 a i 9 . 5 a15.1 a16. .3 a b15. .7 b3. ,7 35. .6 a4. 6 ( 3.9) ( 0.1) ( 3. 2) ( 1.5) ( 2. 8) ( 2. 0) ( 2. ,3) ( 2. 1) - ( 2. 3) Annual 22. 7 19. 6 21. .1 12.9 17. ,2 15. .1 6. .0 4, .7 5. 3 ( 2.7) ( 3.6) ( 3. 5) ( 3.9) (11. 3) ( 8. • 4) ( 3. 6) ( 8. 8) ( 6. 6) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) F C F C F+C F C F+C F C F+C Conifers Tsuga heterophylla Spring 2 2 a65. 4 b71. 0 a68. 2 a34, .6 b29.0 a31, .8 a32. .2 322. .9 a27. .6 ( o. 5) ( 8. 3) ( 5. 8) ( 0, .5) ( 8.3) ( 5. 8) ( o. 7) ( 7. 5) ( 6. • 9) Summer 2 2 a66. 0 a b64. 6 a b65. 3 a34, .0 a b35.4 a b34. .7 a35. .0 a37. .5+ a36. ,2 ( 7. 7) ( 5. 4) ( 5. 5) ( 7. 7) ( 5.4) ( 5. • 5) (12. • 7) (12. .3) (10. .3) Fall-Winter 6 6 a59. 6 a61. 0+ b60. 3 a40, .4+ a39.0 b39. ,7 a32. .8 a34. .8 a33. .8 ( 5. 5) ( 5. 4) ( 5. 3) ( 5, .5) ( 5.4) ( 5. 3) ( 3. 0) (11. .6) ( 8. 2) Annual 10 10 62. 0 63. 7 62. 8 38. .0 36.3 37. .2 33. .1 32. .9 33. .0 ( 5. 8) ( 6. 7) ( 6. 1) ( 5. 8) ( 6.7) ( 6. 1) ( 4. 9) (11. .3) ( 8. 5) Acid-Detergent Lignin Cellulose Hemicellulose ( Percent of oven dry weight ) F C F+C F C F+C F C F+C Conifers Tsuga heterophylla, (continued) Spring a l 9 . , 3 a l 3 . 7 a16.5 a l 2 . ,9 a9.2 a l l . .1 a b2, .4 a6, .1 a4. .2 ( 3. • 2) ( 5.8) ( 5.0) ( 2. 5) ( 1.7) ( 2, • 8) ( o, .2) ( o, .9) ( 2. 2) Summer a22. ,7 a i 8 . 3 a20.5 312. .3 ai9.2 a!5. .7 a - o , .9 a-2, .1 a b - l . ,5 ( 1. 5) ( 4.3) ( 3.7) (11. .2) ( 8.0) ( 8. 9) ( 4, .9) ( 6, .9) ( 4. 9) Fall-Winter a i 9 . ,5 a11.7 a15.6 a15. .1 a33.5 a24, .3 b7. .6 a, .3 b5. .9 ( o. .3) ( 8.7) ( 6.8) ( o. .8) (26.9) (18. .8) ( 3. 8) ( 6. • 7) ( 5. 5) Annual 20. .5 14. 6 17.5 13. .4 20.6 17, .0 4. .9 3. .4 4. ,1 ( 2. 3) ( 5.9) ( 5.3) ( 5. 3) (16.7) (12, .4) ( 5. 0) ( 6. 3) ( 5. 6) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) 1  F C F C F+C F C F+C F C F+C Lichens Alectoria sarmentosa Spring 2 a83.0 a17.0 a4.0 ( 1.7) ( 1.7) ( - ) Summer 3 a77.2 a22.8 a15.5 ( 8.3) ( 8.3) (10.6) Fall-Winter 6 a75.7 a24.3 a5.9 ( 6.3) ( 6.3) ( 5.6) Annual 11 77.5 22.6 8.2 ( 6.5) ( 6.5) ( 7.8) Acid-Detergent Lignin Cellulose Hemicellulose  •. ( Percent of oven dry weight ) F C F+C F C F+C F C F+C • Lichens Alectoria sarmentosa, (continued) Spring a3.0 a i . o a13.0 ( 1.4) ( 1.4) ( 1.7) Summer a3.3 a12.2 a7.3 ( 0.2) (10.8) (18.8) Fall-Winter 31.6 a2.7 a18.4 ( 0.2) ( 0.3) ' ( 8.1) Annual 2.7 6.3 14.4 ( 1.0) ( 8.4) (11.4) Table 3-9. continued. Neutral-Detergent Acid-Detergent Ce l l Contents Fibre Fibre — ( Percent of oven dry weight ) F+C F C F+C F . C F+C Forbs Epilobium angustifolium Spring 2 a87.2 a12.8 a11.2 ( 6.A) ( 6.4) ( 4.4) Summer 2 a73.8 a26.2 a14.9 ( 8.4) ( 8.4) ( 4.1) Fall-Winter 1 a55.8 a44.2 a21.3 Annual 5 75.6 24.5 14.7 (1A.0) (14.0) ( 5.1) Acid-Detergent Lignin Cellulose Hemicellulose ( Percent of oven dry weight ) F C F+C F C F+C F C F+C Forbs Epilobium angustifolium, (continued) Spring a6.1 a5.1 a l . 7 ( 2.9) ( 1.5) ( 2.1) Summer a3.4 a b11.5 a11.3 ( 1.6) ( 2.5) (12.6) Fall-Winter a4.9 ' b16.5 a22.9 Annual 4.8 9.9 9.8 ( 2.1) ( 5.1) (10.9) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents Fibre Fibre ( Percent of oven dry weight ) F C F C F+C F C F+C F C F+C Ferns Blechnum spicant Spring 2 2 a48.8 a50. 7 a49. 7 a51.3 a49.3 a50, .3 350. .4 a45. .8 a48, .1 ( 9.2) (11. 8) ( 8. 7) ( 9.2) (11.8) ( 8, .7) ( 1. • 1) (11. .6) ( 7, .2) Summer 2 2 a37.3 a55. 1 a46. 2 a62.8 a44.9 a53, .8 • b74. .7 a47. .8 a61. .2 ( 1.0) ( 7. 2) (11. 1) ( 1.0) ( 7.2) (11, .1) ( o. 4) (11. .5) (16. .9) Fall-Winter 5 5 a45.7 a56. 4+ a51. 0 a54.3++ a43.7 a49. .0 a45. ,0+ a34. .3 a40. ,1 ( 5.9) ( 3. 2) ( 7. 2) ( 5.9) ( 3.2) ( 7. 2) ( 3. ,6) ( 4. 5) ( 6. 8) Annual 9 9 44.5 54. 8++ 49. 7 55.5++ 45.2 50. .3 52. .0++ 39. ,8 46. ,1 ( 6.8) ( 5. 9) ( 8. 2) ( 6.8) ( 5.9) ( 8, .2) (12. 5) ( 9. ,3) ( 9. 4) Acid-Detergent Lignin Cellulose Hemicellulose ( Percent of oven dry weight ) F C F+C F C F+C F C F+C Ferns Blechnum spicant, (continued) Spring a20.0 a l 9 . 4 a19.7 a30. .5 a26.4 a28. 4 bo. .9 b3.5 a2. .2 (12.7) ( 4.1) ( 7.7) (13. .8) (15.7) (12. 3) ( 8. 1) ( 0.2) ( 4. 9) Summer a28.0 a12.7 a20.3 a46. .7 a35.1 a40. 9 a - l l . ,9 b c-2.9 a-7. .4 ( 3.6) ( 8.6) (10.4) ( 4. 0) ( 2.9) ( 7. 3) ( 1. 3) ( 4.2) ( 5. 8) Fall-Winter 310. 9 al.3.0 a11.9 a35. .8 a25.7 n30. 7 b9. ,2 a9.4 a9. .3 ( 0.2) ( 9.0) ( 5.3) ( 4. 5) ( 6.9) ( 7. 5) ( 4. 7) ( 3.6) ( 3. 9) Annual 19.6 15.0 17.3 37. .7++ 29.1 31. 8 2. .7 5.3 4. .2 ( 9.6) ( 6.8) ( 8.3) (10. .0) ( 9.1) ( 9. 0) (10. .0) ( 6.0) ( 7. 5) Table 3-9. continued. Neutral-Detergent Acid-Detergent N C e l l Contents F i b r e F i b r e ( Percent of oven dry weight ) F C F C F+C F C F+C F C F+C Ferns Polystichum munition Spring 2 2 a40.8 a 4 9 . 5 a45.1 a59.3 a50. ,5 a54, .9 a54 .2 a53 .5 a53, .8 (24.0) (10. 1) (15.8) (24.0) (10. 1) (15. .8) ( 2 .9) ( 6 .8) ( 4, .3) Summer 2 2 a29.4 b 3 3 . 9+ b31.6 370.7+ b66. 1 b68. ,4 a54 .5 a56 .5 a55. .5 ( 0.4) ( 1. 2) ( 2.7) ( 0.4) ( 1. 2) ( 2. 7) ( 3 .0) (10 .5) ( 6. 4) F a l l - W i n t e r 5 5 a30.5 a b 3 8 . 2+ a b 3 4 . 3 a69.5++ 3 b 6 1 . 8 a b 6 5 . ,7 a51 .3 3 5 0 .9 a 5 1 . .1 ( 3.9) ( 5. 6) ( 6.1) ( 3.9) ( 5. 6) ( 6. 1) < .8) ( 7 .0) ( 5. 6) Annual 9 9 32.5 39. 7++ 36.1 67.5++ 60. 3 63. .9 52 .6 52, .7 52. ,7 (10.1) ( 7. 9) - ( 9.5) (10.1) ( 7. 9) ( 9. 5) ( 4 .1) ( 7, .0) ( 5. 6) Acid-Detergent L i g n i n C e l l u l o s e H e m i c e l l u l o s e ( Percent of oven dry weight ) • F C F+C F C F+C F C F+C Ferns Polystichum munition, (continued) Spring a30.0 a24.0 a27.0 a24.3 a29.5 a26.9 a5.1 a-3.0 ai.o ( 0.5) ( 2.0) ( 3 . 6 ) ( 2.4) ( 4 ..8) ( 4.3) (26.9) ( 3 . 3 ) (16.3) Summer b 2 3 . 5 a 2 6 . 8 a 2 5 . 1 a31.0 8 29.7 fl30.3 a16.2 a9.6 a12.9 ( 1 . 1 ) ( 5 . 5 ) ( 3.8) ( 1.9) ( 5.0) ( 3.2) ( 2.6) (11.6) ( 7.9) F a l l - W i n t e r b24.2 a26.0 a25.1 a29.5 a30.4 329.9 a18.2 310.9 • a14.6 ( 0 . 3 ) . ( 1 . 4 ) ( 1.3). ( 3.9) ( 7,3) ( 4.8) ( 2.6) ( 8.9) ( 7.3) Annual 25.9 25.6 25.7 28.2 29.8 29.0 14.8 7.5 11.6 ^ ( 3.2) ( 3.0) ( 3.0) ( 3.9) ( 4 . 5 ) ( 4.2) (11.2) I. 9- 7V (10.4) jo 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) are not d i f f e r e n t at p < 0.05 l e v e l as determined 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 . 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 s i n fore s t e d and cutover areas i n d i c a t e d as: + (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 beside the measure having the greater value. 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) levels i n Pseudotsuga  menziesii during the growing season. In most seasons, c e l l content and NDF were not different i n a species collected i n timber compared to cut-over areas. Where differences did occur, higher levels of c e l l content and lower levels of NDF were observed i n plants 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 similar to those observed for dry matter, crude protein and DDM. Plants of similar struc-ture (e.g., conifers) or closely 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. Among the species examined, NDF content ranged from 63.9 (±2.2%) i n Polystichum muniturn to 22.6 (±1.9%) i n Alectoria sarmentosa. NDF did not show any trend of increased levels i n woody species such as shrubs and conifers, as might be expected. Rather, ferns, which generally are considered herbaceous, contained high levels of NDF due to t h e i r high l i g n i n and cellulose content which i s discussed l a t e r i n conjunction with those components. To summarize, Alectoria sarmentosa was lowest i n NDF and highest i n c e l l contents of a l l species studied. This was reflected 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 i s o l i c h e n i n (Scotter 1972) which may not react i n the same way to the Van Soest deter-gent 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 lichen samples suggested this was the case. Courtright (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 lichens, which would reduce t o t a l f i b r e (NDF). 135 Low lignin levels were also observed in 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 in 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 in 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 ever-green 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 its compo-nents, cellulose and ADL, are relatively low in digestibility, ADL (lignin) being essentially indigestible (Van Soest 1963). Short and Reagor (1970) reported that cell wall content (NDF) 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 contained similar levels of ADL; shrubs were significantly 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% (+2.7%) in ferns in summer to a low of 1.0% (±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 than Blechnum spicant, reflecting its more woody structure. 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 varia-tion between seasons was evident for most species. The few statistical departures are indicated in 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 al. (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 compo-nents may precede major phenological changes, such as bud burst, upon which season delineations were based. In leaves, Short et al. (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 is 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 con-tained in Table 3-10. Polystichum munitum contained highest levels of ADF and ADL, 52.7 (±1.3%) and 25.7 (±0.9%), respectively. Corresponding 1 3 9 T a b l e 3 - 1 0 . 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 n n u a l f i b r e c o n t e n t s o f f o r a g e s p e c i e s . V a l u e s a r e ^ a v e r a g e s 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 c u t o v e r a r e a s c o m b i n e d . NEUTRAL-DETERGENT FIBRE POMU VAAL VAPA BLSP V/////////////////////, GASH PSME THPL ' TSHE //////////////////////, EPAN A L S A 6 3 . 9 53.1 50.4 5 0 . 3 4 4 . 9 4 0 . 6 4 0 . 6 37 .1 2 4 . 5 2 2 . 6 ACID-DETERGENT FIBRE POMU BLSP '//////////////////////, VAAL VAPA GASH THPL TSHE PSME •••••••••••••••••••••••••••••••••••••• V///////////////////// EPAN ALSA 52.7 46 .2 4 0 . 4 3 9 . 5 3 7 . 8 3 5 . 2 3 3 . 0 31.6 1 4 . 7 8 . 2 ACID-DETERGENT LIGNIN POMU THPL '///, VAAL GASH '/////////////, PSME TSHE \ \ \ \ 3LSP VAPA EPAN A L S A 25.7 21.1 1 8 . 5 1 8 . 4 1 8 . 0 1 7 . 5 17.3 1 6 . 0 . 4 . 8 2.7 CELLULOSE ^ ^ ^ ^ BLSP POMU ^ ^ ^ ^ 33.3 2 9 . 0 HEMICELLULOSE VAPA VAAL GASH 2 4 . 1 2 1 . 0 1 9 . 1 //////////////////////. TSHE THPL PSME '////////////////////// 1 7 . 0 15.1 1 3 . 5 EPAN 9 . 9 A L S A 6 . 3 ALSA VAAL \ \ \ \ ^ POMU V//. '///////////// VAPA EPAN PSME GASH THPL T S H E B L S P 14.4 1 2 . 6 1 1 . 2 1 1 . 0 9 .8 8 . 9 7 .1 5 .3 4 . 1 4 . 0 ' F o r a g e s p e c i e s c o d e s and t y p e d e s i g n a t i o n s a r e a s f o l l o w s : SHRUBS v.- .- .- GASH = Gaultheria shallon CONIFERS / / / / . PSME = Pseudotsuga menziesii LICHEN ALSA - Alectoria sarmentosa FORBS EPAN •» Epilobium angustifolium FERNS s\\v BLSP = Blechnum spicant ' VAAL » Vaocinium. alaskense THPL = Thuja plicata POMU = Polystichum munitum VAPA « ' / . parvifolium TSHE = Tsuga hetercphyl ^ V a l u e s a r e p e r c e n t o f o v e n d r y w e i g h t . S p e c i e s n o t 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 . 0 5 ) a s d e t e r m i n e d b y 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 . 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 compo-nents 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 differ-ent from the lignocellulose common to most other plant types. Forbs were low in ADF, ADL and cellulose due to their herbaceous nature and corre-spondingly 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 al. (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 may also have influenced the patterns observed. 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 cor-respondingly 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 charac-teristic 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. In the analysis, conducted according to the procedures of Waldren (1971), separate plant samples were digested in acid-detergent and in neutral-detergent solutions. Robbins et al. (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 first 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. The effect of this incomplete separation would be an over-estimate of ADF and a corresponding underestimate of hemicellulose. Short et al. (1975) had the same discrepancy in 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 hemicellu-lose 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 signifi-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 hemicellu-lose than lichens and forbs (Table 3-7). Within forage types, significant seasonal differences in hemicellulose occurred only in 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 its solubility in artifi c i a l saliva (Uresk et al. 1975). In this study seasonal patterns of solu-bility 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 A l e c t o r i a sarmentosa Vaccinium parvifolium p < 0.116 S o l u b i l i t y (%) D i g e s t i b i l i t y (%) S o l u b i l i t y (%) D i g e s t i b i l i t y ' 40 30 20 h 10 |-n70 4 0 r 30 20 10 0 70 60 50 40 0 Oct Jan Apr J u l Oct Jan Apr J u l Figure 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 plant 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. Points are means of d u p l i c a t e samples. Analysis by paired T t e s t . - O = average d i g e s t i b i l i t y of tissue c o l l e c t e d i n forested and cutover areas, ---A. = s o l u b i l i t y of tissues c o l l e c t e d i n cutover areas, • = s o l u b i l i t y of tissues c o l l e c t e d i n forested areas. 145 S t a t i s t i c a l comparisons (paired t-tests) of s o l u b i l i t y levels i n plants from forested and cutover areas showed that differences occurred, i n Blechnum spicant (p < 0.04), Thuja p l i c a t a (p < 0.06) and Vaccinium  parvifolium (p < 0.12), with the highest levels 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 D i g e s t i b i l i t i e s of the forage mixtures evaluated are presented i n Table 3-11. Sixteen different diets were evaluated and i n 12 of these, DDM was greater than expected on the basis of the proportional combination of DDM for individual component species. D i g e s t i b i l i t y increases ranged from 5.9 to 29.7 percent above expected levels. The greatest increases i n d i g e s t i b i l i t y of diets over expected levels occurred during May, when DDM of individual species was r e l a t i v e l y high. In 4 of the 16 di e t s , DDM was less than the calculated proportional DDM of the individual species (mean decrease = 7.7%). The reasons for th 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, with diets that consisted of species which are primarily winter foods (Gaultheria  shallon, Alectoria sarmentosa, Thuja p l i c a t a and Vaccinium alaskaense, the l a t t e r receiving more use on a year-round basis than the former three species). The reduced DDM of these diets over that expected may have re-sulted from the rumen microbial population being adapted to a rather different summer diet and not having the capacity at th i s time of year to digest a diet commonly used i n winter. The remaining case of reduced DDM of a diet occurred i n February, i n a diet composed of three conifer species and Alectoria sarmentosa. The reasons for this decrease are not Table 3-11 . Dry matter d i g e s t i b i l i t y of forage mixtures r e l a t i v e to expected 1 DDM based on values for Individual species. Diet Month Species Composition Propor- Expected Expected Observe tion Observed spp Diet Diet of spp DDM DDMe DDMn Diet DDM <%) (%) (%) 0.33 72.0 24.0 0.33 46.0 15.3 56.0 59.5 0.33 50.0 16.7 0.50 72.0 36.0 0.25 46.0 11.5 60.0 65.3 0.25 50.0 12.5 0.33 24.0 8.0 0.33 50.0 16.5 43.3 36.7 0.33 57.0 18.8 0.33 22.0 7.3 0.33 36.0 12.0 36.3 38.8 0.33 51.0 17.0 0.33 24.0 8.0 0.33 50.0 16.5 48.9 47.4 0.33 74.0 24.4 0.33 22.0 7.3 0.33 36.0 12.0 0.33 74.0 24.4 43.7 39.3 0.25 50.0 12.5 0.25 46.0 11.5 57.3 56.0 0.25 52.0 13.0 0.25 81.0 20.3 Difference (DDM -DDM )/ o e DDM e (%) Slash Diet Forb-Shrub Slash Diet Forb-Shrub July July Slash Diet August Shrub-Conifer Timber Diet August Shrub-Conifer Slash Diet August Shrub-Conifer-Lichen Timber Diet Shrub-Conifer-Lichen Timber Diet Conifer-Lichen August February Epilobium angustifolium Rubus spectabilis Vaccinium parvifolium Epilobium angustifolium Rubus spectabilis Vacainium parvifolium Gaultheria shallon Vaaainium alaskaense Thuja p l i c a t a Gaultheria shallon Vaccinium alaskaense Thuja p l i c a t a Gaultheria shallon Thuja p l i c a t a Alectoria sarmentosa Gaultheria shallon Thuja p l i c a t a Alectoria sarmentosa Thuja p l i c a t a Tsuga heterophylla Pseudotsuga menziesii Alectoria sarmentosa -15.2 3.1 -10.1 - 2.3 Table' 3-11. continued. Propor-Observed Expected Expected Observed Differem (DDM -DDM t i o n spp Diet Diet O l of spp DDM DDM DDMQ DDM Diet Month Species Composition Diet DDM (%) (%) (%) (%) G Timber Diet February Thuja plicata 0.25 50.0 12.5 Conifer-Shrub- Gaultheria shallon 0.25 32.5 8.1 50.9 55.0 + 8.1 Fern-Lichen Blechnum spicant Alectoria sarmentosa 0.25 0.25 40.0 81.0 10.0 20.3 Slash Diet February Vaccinium alaskaense 0.25 36.0 9.0 Shrub-Fern Vaccinium parvifolium Gaultheria shallon Blechnum spicant 0.25 0.25 0.25 33.0 40.5 59.5 8.3 10.1 14.9 42.3 44.8 + 5.9 Slash Diet Mar ch Vaccinium alaskaense 0.20 33.0 6.6 Shrub-Fern Vaccinium parvifolium Gaultheria shallon Blechnum spicant 0.20 0.40 0.20 46.5 36.5 42.5 9.3 14.6 8.5 39.0 42.1 + 7.9 Slash Diet A p r i l Gaultheria shallon . 0.33 26.0 8.6 Shrub-Fern- Blechium spicant 0.33 32.5 10.7 36.6 43.7 +19.4 Conifer Thuja plicata 0.33 52.5 17.3 Timber Diet A p r i l Vaccinium alaskaense 0.25 27.5 6.9 Shrub—Lichen Vaccinium parvifolium GaultJieria sJiallon Alectoria sarmentosa 0.25 0.25 0.25 32.5 22.0 74.5 8.1 5.5 18.6 39.1 47.1 +20.5 Slash Diet May Vaccinium alaskaense 0.25 65.0 16.3 Shrub-Fern Vaccinium parvifolium Pteridium aqualinum Polystichum munition 0.25 0.25 0.25 51.5 48.0 18.5 12.9 12.0 4.6 45.8 59.4 +29.7 Table 3-11. continued. Propor- Expected Expected Observed Difference tion Observed SPP Diet Diet (DDM0-DDMe)/ of spp DDM DDMe DDMQ DDMe Diet Month Species Composition Diet DDM (%) (%) (%) (%) Slash Diet May Rubus spectdbilis 0.25 35.5 8.9 Shrub-Conifer Sambucus racemosa 0.25 77.5 19.4 55.7 60.9 + 9.3 Vaccinium parvifolium 0.25 51.5 12.9 Thuja plicata 0.25 58.0 14.5 Timber Diet May Vaccinium parvifolium 0.25 59.5 14.9 Shrub-Fern- Vaccinium alaskaense 0.25 58.0 14.5 48.0 61.2 +27.5 Lichen Polystichum munitum 0.25 24.0 6.0 Alectoria sarmentosa 0.25 50.0 12.6 Timber Diet May Gaultheria shallon 0.25 15.0 3.8 Shrub-Conifer- Thuja plicata 0.25 45.5 11.4 Lichen Tsuga heterophylla 0.25 32.0 8.0 35.8 45.1 +26.0 Alectoria sarmentosa 0.25 50.5 12.6 'Expected contribution to tot a l d i g e s t i b i l i t y = proportion of diet x measured d i g e s t i b i l i t y . 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 al. 1968). There were no consistent patterns of variation in DDM 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 of diets. The high proportion (75%) of cases in which DDM of diets exceeded expected levels based on DDM of individual species suggests the presence of an enhancement effect. The most likely mechanism for this effect is that within 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 evaluations of mixtures was carried out to determine i f increasing the proportion of a highly digestible species, Alectoria sarmentosa, progressively enhanced DDM over expected values based on proportional digestibilities of diet components. Results of this series of tests are presented in Table 3-12. Statistical analysis of variance indicated 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 of individual species, but also that DDM of diets Is further enhanced as the proportion of A, sarmentosa in the diet increases. This finding suggests that in winter when most use of A. sarmentosa occurs, its 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 increasing proportions of Aleotovia sarmentosa, March 1974. Species Diet Observed Spp Expected Spp 1 Expected Diet Observed D i e t 2 Composition Proportion DDM (%) DDM (%) DDM (%) DDM (%) Difference (%) 3 Diet 1 Thuja plicata 0.25 54.5 13.6 Gaultheria shallon 0.25 34.0 8.5 Blechnum spicant 0.25 36.5 9.1 51.7 54.6 + 5.5 Alectoria sarmentosa 0.25 82.0 20.5 Diet 2 Thuja plicata 0.20 54.5 10.9 Gaultheria shallon 0.20 34.0 6.8 Blechnum spicant 0.20 36.5 7.3 57.8 65.4 +13.0 Alectoria sarmentosa 0.40 82.0 32.8 Diet 3 Thuja plicata 0.167 54.5 9.1 Gaultheria shallon 0.167 34.0 5.7 Blechnum spicant 0.167 36.5 6.1 62.0 68.3 + 9.9 Alectoria sarmentosa 0.501 82.0 41.1 Diet 4 Thuja plicata 0.143 54.5 7.8 Gaultheria shallon 0.143 34.0 4.9 Blechnum spicant 0.143 36.5 5.2 64.8 75.0 +15.7 Alectoria sarmentosa 0.572 82.0 46.9 1 Expected contribution to t o t a l d i g e s t i b i l i t y = proportion of di 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 Differences 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 at (p _ 0.0001) o SUMMARY - DIGESTIBILITY, NUTRIENT AND FIBRE CHARACTERISTICS D i s t i n c t seasonal patterns were observed i n most nutrient and f i b r e meas-ures and were related to the phenological stage of the plant. Results generally follow those observed i n s i m i l a r studies i n other f o r e s t types (Short et a l . 1971, 1975, Whelan et a l . 1971). Dry matter content i n -creased from spring to the f a l l - w i n t e r season, r e f l e c t i n g the change i n f i b r e components which occurs during the process of maturation. During the spring period of rapid e a r l y growth, woody browse species 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 plants (Cushwa et a l . 1970). Shoot growth may be completed by early summer and associated with t h i s cessation of growth i s a thickening and l i g n i f i c a t i o n of c e l l walls (Isenberg 1963). Short et a l . (1975) documented a s i m i l a r increase i n dry matter content associated with seasonal development of a number of browse species i n the southeastern United States. D i g e s t i b i l i t y l e v e l s were highest i n most species at the time of i n i t i a -t i o n of new growth i n the spring. Notable exceptions to t h i s pattern occurred i n A l e c t o r i a sarmentosa and ferns. Levels of l i g n i n were high In ferns at t h i s time, an apparent contradiction, since l i g n i n content normally increases with maturation of plant t i s s u e . I t i s possible that other changes i n chemical composition were occurring at t h i s time i n ferns and either influenced DDM d i r e c t l y or i n some manner affected the analysis for l i g n i n . Temporal changes i n forage q u a l i t y parameters were generally of l e s s e r magnitude i n evergreen than i n deciduous species. Fibre compo-nent l e v e l s remained r e l a t i v e l y constant throughout the year i n coniferous species. Leaf drop i n shrubs or dieback of above ground portions 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 these p l a n t types. M i n e r a l content was not measured i n t h i s study but has been shown to undergo l a r g e changes w i t h l e a f a b c i s s i o n (Short et al. 1966) and probably i n f l u e n c e d DDM l e v e l s . A crude p r o t e i n content of 7% i s required f o r forages to meet deer main-tenance needs (Dietz 1965). Among forage types examined i n t h i s study, ferns had year-long values greater than 7%, shrubs and Epilobium a n g u s t i -f o l i u m exceed 7% crude p r o t e i n l e v e l s i n s p r i n g and summer, and l i c h e n s and c o n i f e r s contained l e s s than t h i s l e v e l throughout most of the year. As noted e a r l i e r , the p l a n t species s e l e c t e d i n t h i s study were those observed to receive high l e v e l s of use at some time during the year as i n d i c a t e d by analyses of rumen contents. Many other species w i t h a wide range of n u t r i e n t content were fed upon at various times of the year. Although these may have c o n t r i b u t e d to year-round food h a b i t s to a l e s s e r degree than the species t h i s study examined i n d e t a i l , they undoubtedly had important short-term i n f l u e n c e s on deer n u t r i t i o n . This i s suggested by the data i n Table 3-13 i n which the c h a r a c t e r i s t i c s of the " d i e t " s e l e c t e d by deer, are contrasted to the c h a r a c t e r i s t i c s of the "menu" comprised of major species a v a i l a b l e . When a c t u a l forage consumption patterns are examined, i t i s c l e a r t h a t deer s e l e c t forages of higher q u a l i t y than the average a v a i l a b l e . In the case of DDM, the d i e t s e l e c t e d was s u b s t a n t i a l l y more d i g e s t i b l e than the "menu" of p o t e n t i a l forage items. The p a t t e r n i s s i m i l a r f o r crude p r o t e i n except i n the f a l l -w i n t e r p e r i o d . Deer appeared to be s e l e c t i n g f o r high l e v e l s of the r e a d i l y - d i g e s t i b l e c e l l contents, and as a r e s u l t , f i b r e content (NDF, ADF, ADL) of forages consumed was l e s s than t h a t of the "menu." Table 3-13. Seasonal nutrient composition and cejLl components of primary forages consumed by bla c k - t a i l e d deer ("diet") compared to major forages available ("menu") . Spring Summer Fall-Winter Annual Nutrient Component (%) "d i e t " "menu" "d i e t " "menu" " d i e t " "menu" " d i e t " "menu" Dry matter 20.4 32.0 24.1 35.2 40.2 38.5 28.2 36.6 Crude protein 21.6 12.8 13.9 8.0 4.8 6.4 13.4 7.9 Dry matter d i g e s t i b i l i t y 58.2 41.0 70.5 43.8 56.9 42.8 61.9 42.7 C e l l Component (%) C e l l contents 80.4 60.2 72.8 54.9 57.2 52.9 70.1 54.9 Neutral-detergent f i b r e 19.6 39.8 27.2 45.1 41.2 47.1 29.3 45.1 Acid-detergent f i b r e 20.1 35.6 22.4 37.6. 25.3 36.7 22.6 36.7 Acid-detergent l i g n i n 7.4 17.0 3.3 18.4 9.3 16.8 6.7 17.4 Cellulose 12.7 18.6 19.1 19.2 16.6 22.1 16.1 19.9 Hemicellulose 1.2 4.3 9.3 7.4 15.5 10.5 8.7 8.5 Combination of plant species making up majority of forage consumed. Values are weighted according to th e i r percent Importance Value (IV) as determined i n rumen -content analyses. Diets consist of: Spring - Epilobium angustifolium IV - 41, Rubus spp. IV - 26, Cornus canadensis IV .- 12, combined IV = 79% of spring d i e t . -Summer - E. angustifolium IV - 66, Rubus spp. IV - 12, combined IV = 78% of summer d i e t . Fall-Winter - Gaultheria shallon IV = 24, E. angustifolium IV = 23, Alectoria sarmentosa IV - 12, combined IV = 59% of f a l l - w i n t e r d i e t . Variations i n sample sizes and lack of r e p l i c a t e s i n rumen content analyses prevented s t a t i s t i c a l comparisons of " d i e t " and "menu." Combination of forage species examined. "Menu" i s the same i n each season and indicates average values for species group which includes 6Y ehallons Vaccinium alaskaense, V. parvifolium, Pseudotsuga menziesii, Tsuga heterophylla, Thuja plicata, A. sarmentosa, E. angustifolium, Blechnum spicant and Polystichum muni turn. 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 al. 1968) as evidenced by the weight losses which normally occur (Nordan et al. 1968). Comparisons of the same species collected in 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 in amount of canopy closure, with randomly occurring openings. The sampling procedure employed did not select for or against plants growing in openings. Probably more important were micro-climatic differences, which 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. For example, Gaultheria shallon in forested areas produced few or no flowers while plants in cutovers flowered profusely. In areas where samples were col-155 lected, production of new foliage in this species in forests was delayed approximately 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 compo-nents. Enhancement of microbial growth and fermentation capacity asso-ciated with a variety of substrates is the probable mechanism for this effect. Microbial adaption to seasonal forage composition was also suggested by reduced capacity of rumen microbes to 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 artifi 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-Table 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 of nutrient and f i b r e c h a r a c t e r i s t i c s of forage types. Only s i g n i f i c a n t (pf 0.05) values are l i s t e d . Correlations are for mean annual nutrient l e v e l s . Correlation of; Dry Matter with: CPU.2 DDM NDF3 ADF "ADL SHRUBS (n = 63) -0.66 CONIFERS (n «= 62) -0.47 0.54 0.40 FORBS (n - 5) -0.96 0.93 0.91 FERNS (n = 36) -0.52 0.51 Crude Protein with: DDM NDF ADF ADL 0.58 -0.26 -0.38 -0.47 -0.44 -0.41 DDM with: NDF ADF ADL NDF with: ADF ADL ADF with: ADL ' -0.26 -0.42 0.59 0.75 0.49 0.53 -0.44 -0.51 -0.64 0.55 .0.61 Number of measurements. Crude protein. , 3 C o e f f i c i e n t s for c e l l contents same as for NDF except sign i s reversed ( c e l l content -= 1 - NDF). Table 3-15. Cor r e l a t i o n c o e f f i c i e n t s of nutrient and f i b r e c h a r a c t e r i s t i c s of forage types. Only s i g n i values ( p f 0.05) are l i s t e d . Correlations are for mean annual nutrient l e v e l s . i f i c a n t C orrelation of: Dry Matter with: CPR2 DDM NDF3 ADF ADL SHRUBS CONIFERS FERNS Forested (31) 1 Cutover (32) Forested (31) Cutcver (31) Forested (18) Cutover (18) -0 67 -0.67 0.44 -0.56 0.63 0.40 0.36 0.38 -0.52 0.64 -0.52 0.73 Crude Protein with: DDM NDF ADF ADL 0.73 0.50 -0.45 -0.41 -0.40 -0.46 DDM with: NDF ADF ADL NDF with: ADF ADL 0.39 0.72 -0.40 -0.70 0.64 0.64 0.57 0.54 -0.57 -0.74 -0.84 0.71 ADF with: ADL 0.57 Number of measurements. "Crude protein. Coefficients for c e l l contents same as for NDF except sign i s reversed ( c e l l content = 1 NDF) . 0.70 Table 3-16. Corre l a t i o n c o e f f i c i e n t s of nutrient and f i b r e c h a r a c t e r i s t i c s of forage types. Only s i g n i f i c a n t values (p 1 0.05) are l i s t e d . Correlations are for seasonal nutrient l e v e l s . Correlation of: SHRUBS CONIFERS FERNS Dry Matter with: CPR2 DDM NDF3 ADF ADL Crude Protein with: DDM NDF ADF ADL DDM with: NDF ADF ADL Fall-Winter (42) 0.43 0.61 0.70 Spring (12) -0.66 0.86 Summer (16) -0.81 -0.53 -0.78 0.53 Fall-Winter (42) 44 Spring (12) -0.77 0.69 0.70 0.83 -0.63 -0.62 -0.66 Summer (14) -0.80 0.73 -0.63 -0.58 Fall-Winter (24) -0.61 0.62 0.47 -0.80 -0.82 -0.94 Spring (8) 0.73 Summer (8) .73 -0.83 NDF With: ADF ADL 0.76 0.83 0.60 0.79 0.81 0.57 0.80 0.81 0.79 ADF with: ADL 0.94 .. .. -0.61 .. .. 0.74 .. 0.80 'Number of measurements. 2Crude protein. 3 C o e f f i c i e n t s for c e l l contents same as for NDF except sign i s reversed ( c e l l content = 1 - NDF). '! Table 3-17. Correlation c o e f f i c i e n t s of nutrient and f i b r e c h a r a c t e r i s t i c s of shrub species. Only s i g n i f i c a n t values (p_0.05) are l i s t e d . Correlations are for mean annual nutrient l e v e l s . C orrelation of: Dry Matter with: CPR2 DDM NDF3 ADF ADL Crude Protein with: DDM NDF ADF ADL Gaultheria shallon Forested (11)' Cutover (11) 88 -0 72 -0.70 Vaooinium alaskaense Forested (11) Cutover (11) -0.73 -0.78 0.80 0.77 82 0.71 -0.69 Vaooinium parvifolium  Forested ( 9) Cutover (10) -0 75 0.80 -0.67 -0 80 -0.79 DDM with: NDF ADF ADL NDF with: ADF ADL ADF with: ADL . 0.75 0.77 0.79 0.88 0.86 0.82 -0.90 -0.87 -0.84 0.73 0.93 Number of measurements. 2Crude protein. C o e f f i c i e n t s for c e l l contents same as for NDF except sign i s reversed ( c e l l -0.84 0.88 -0.79 -0.64 -0.91 content NDF). Table 3-18. Corre l a t i o n c o e f f i c i e n t s of nutrient and f i b r e c h a r a c t e r i s t i c s of conifer species. Only s i g n i f i c a n t values (pf0.05) are l i s t e d . Correlations are for mean annual nutrient l e v e l s . C o r r e l a t i o n of: Dry Matter with: CPR2 DDM NDF3 ADF ADL Pseudotsuga menziesii Forested(10)' Cutover(10) 64 -0.81 0.68 0.76 0.94 Thuja plioata Forested (H) Cutover (n) -0.66 0.63 -0.79 Tsuga heterophylla Forested (10) Cutover (10) -0.67 0.83 Crude Protein with: DDM NDF ADF ADL -0.77 -0.74 0.63 -0.62 -0.70 -0.64 DDM with: NDF ADF ADL -0.64 -0.96 NDF with: ADF ADL 0.62 0.88 ADF with: ADL Number of measurements. 2Crude protein. 3 C o e f f i c i e n t s for c e l l contents same as for NDF except sign i s reversed ( c e l l content = 1 - NDF). Table 3-19. Co r r e l a t i o n c o e f f i c i e n t s of nutrient 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. Only s i g n i f i c a n t values (p_0.05) are l i s t e d . Correlations are for mean annual nutrient l e v e l s . C o r r e l a t i o n of: Dry Matter with: CPR2 DDM NDF3 ADF ADL Crude Protein with: DDM NDF ADF ADL DDM with: NDF ADF ADL NDF with: ADF ADL Epilobium angustifolium Cutover(5) -0.96 0.93 0.91 Blechnum spicant  Forested (9) 1 Cutover (9) -0.73 0.68 -0.87 75 -0.71 -0.88 0.78 Polystichum munitum Forested (9) Cutover (9) -0.95 -0.92 0.83 0.90 -0.70 0.87 ADF with: ADL Number of measurements. 2Crude protein. "Coefficients for c e l l contents same as for NDF except sign i s reversed ( c e l l content = 1 NDF). 0.89 163 vestigators (Urness and McCulloch 1973, Robbins et al. 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 posi-tive 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 in summer, and a negative rela-tionship in the same plants in winter. They attributed this finding to the increasing lignification associated with plant maturation which de-creased the digestibility of cellulose. Short et al. (1973) also noted that fibre-DDM relationships were different in immature than in mature woody shoots. Similar seasonal variations in degree of correlation occurred in the present study (Table 3-16) with varied patterns between forage types. The negative correlation of various fibre components and DDM" was rela-tively 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 1 6 4 (Short and Reagor 1970, Short et al. 1974) who attribute i t to the dif-ferent levels of lignin in varied plant types. They observed that as the cell wall content of herbages, which contain low levels of lignin, in-creased, 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 respon-sible 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 al. (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 com-ponents that affect either digestibility or the reliability of detergent-fibre 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 in com-bination (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. Correlation coefficients for individual forage species collected in timbered and cutover areas are presented in Tables 3-17, 3-18 and 3-19. 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 in Alectoria sarmentosa, probably a result of its 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 in 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 in 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 in the two Vaccinium species which showed consistent negative relationships of fibre to DDM, while in Gaultheria shallon, the other shrub evaluated, this relationship was absent. 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 the apparent relationships indicated by correlations of nutrient and fibre characteristics, and reports of other investigators (Short et al. 1973) indicating useful predictor variables, stepwise multiple regression was employed to explore predictive relationships between these characteristics and in vitro DDM. 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 DDM in individual species. Within shrubs, crude protein, dry matter, cell content and acid-detergent lignin each showed significant relationships to DDM although generally higher, r^ values were associated with the cell contents measure. Short et al. (1973) observed a similar relationship in summer twigs of the combined group of species they studied. Acid-detergent lignin and crude protein had a close relationship to DDM in conifers. In ferns, crude protein level can be used to predict digesti-bility, 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 may exhibit a poor relationship in the same species from forested areas. Correlations generally 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 in vitro 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 (Cell C), acid-detergent fibre (ADF) and acid-detergent lignin(ADL). DDM values predicted are mean annual levels. Significance Coefficient Species Area a Regression Equation Level of F Test of Determination — [Fry— Gaultheria shallon C y 43.95 - 2.31 (CPR) 0.05 0.49 y = 87.29 - 0.88 (DRY) - 4.11 (CPR) 0.05 0.77 Vaccinium alaskaense F y 19.50 + 1.76 (CPR) 0.04 0.60 y = 63.23 - 0.79 (DRY) 0.01 0.61 Vaccinium alaskaense a C y = -39.07 + 1.55 (Cell C) 0.01 0.82 Vaccinium parvifolium F y = 4.11 + 0.90 (Cell C) 0.01 0.70 Vaccinium parvifolium C y = 82.87 — 2.47 (ADL) 0.01 0.83 y 9.55 + 0.74 (Cell O 0.01 0.63 Pseudotsuga menziesii C y 131.36 — 5.3 (ADL) 0.01 0.93 y = 50.5 + 3.53 (CPR) - 0.31 (Cell C) 0.05 0.66 Thuja plicata F y 23.72 + 5.56 (CPR) 0.01 0.77 y — 50.5 + 3.53 (CPR) - 0.31 (Cell C) 0.05 0.65 Blechnum spicant F y = 55.17 - 1.74 (CPR) 0.05 0.79 Blechnum spicant C y 56.9 — 1.4 (CPR) 0.05 0.50 Area designation: F = Forested; C cs Cutover 168 correlation of forage characteristics was high between different types, reflecting their variable composition. Regression analysis identified several forage characteristics which sig-nificantly influenced DDM. Variability in importance of particular characteristics was high, depending on plant species and area of collec-tion. 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 ful 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 al. (1969) and Short (1975). In the first study, rumen dry matter 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 the latter study, similar differences in 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 di-gestibility and turnover rates of rumen contents. With improved quality of feed, forage intake rates increase as shown by Ullrey et al. (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 in 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 in 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 in turn reduces forage intake rates. Ammann et al. (1973) observed in white-tailed deer that as di-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 digesti-bility 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 containing highest protein levels as substantiated by analyses of both forage and rumen contents. 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 indi-vidual plants or plant parts richest in nitrogen (Longhurst et al. 1968, Swift 1948). Analyses of gross rumen contents indicate combined levels of forage 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 al. (1969) using chemical components, in-cluding protein level, of rumen contents. 171 In the present study, crude protein level of rumen contents was measured to examine its 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 in a forced-draft oven. Dry matter content as a percentage of wet weight was then calculated. Rumen F i l l Total weight of the rumen and its contents was determined prior to samp-ling for food habits, dry matter and in 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 using the micro-Kjeldahl procedure of Nelson and Sommers (1973). Crude protein was calculated using the conversion: percent nitrogen x 6.25 = percent crude protein. RESULTS AND DISCUSSION Dry Matter Content Seasonal levels of dry matter in rumen contents of deer collected in cutover and forested areas are presented in Table 3-21. Monthly dry matter contents are listed in Table 3-22 and graphically displayed in Figure 3-10. 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 al. (1969) except they showed high dry matter levels in fa l l associated with extensive use of acorns. Short et al. (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 protein 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 forested and cutover areas. Rumen F i l l 1 - (%) Rumen Matter Dry - (%) Crude Rumen Protein - (%) n X (S.D.) n X (S .D.) n X (S.D.) Spring Forested 2 10.9 (3.9) 2 13 .6 (0.4) 2 32. 4 (5.7) Cutover 10 7.6 (2.2) 10 12 .8 (1 .3) 10 39. 9 (2.7)* Forested and Cutover 12 8.2 (2.6) a 12 12 .9 (1 • 2 ) 3 38. 7 (4.2) a Summer Fo res ted • _ _ _ Cu Cover 15 10.8 (2.0) b 15 13 .3 (1, ,0) a 14 27. 7 (9.3) b Forested and Cutover - - -Fall-Winter Forested 8 13.3 (2.1) 6 16 .0 (1. .4) 6 13. 7 (1.8) Cutover 21 13.0 (3.2) 21 14 .6 (1. • 9 )h 21 18. 5 (5.5)* Forested and Cutover 29 13.1 (2.9) c 27 14 .9 (1. .9) b 27 17. 4 (5.3) c Annual Forested 10 12.8 (2.5) 8 15 .4 (1. ,6)* 8 18. 4 (9.1) Cutover 46 11.1 (3.3) 46 13 .8 (1. .7) 45 26. 1 (10.6)i Forested and Cutover 56 11.4 (3.2) . 54 14 .0 (1. .8) 53 24. 9 (10.7) 1Runien f i l l = weight of rumen contents expressed, as a percentage of body weight. * Indicates 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); superscript i s beside the higher value i n forested and cutover comparisons. c Indicates 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 analysis of variance. Seasonal means for combined forested and cutover areas having a common superscript are not d i f f e r e n t (p < 0.05). Table 3-22. Monthly l e v e l s of rumen f i l l and dry matter and crude protein i n rumen contents of b l a c k - t a i i e d deer. Values are combined means for deer from forested and cutover areas. Rumen Rumen Rumen F i l l - (%) Dry Matter - (%) Crude Protein - (%) n X (S D.) n X (s D.) n 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) A p r i l 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) Augus t 10 11. 1 (2 2) 10 13 3 (0 9) 10 25 3 (10. 0) September 1 10. 5 ( -- ) 1 13 5 - ) • -October 2 8 6 (1 9 > 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) Annual 56 11 4 (3 2) 54 14 0 (1 8) 53 24 9 (10. 7) 3Rumen f i l l = weight of rumen contents expressed as a percentage of body 'weight. 175 Percent 44 40 36 32 28 24 20 16 12 8 4 0 s. crude p r o t e i n 9 \ \ dry. matter m'Slr*—-«» rumen f i l l _i_ a I i ; ' « i L Jan Feb Mar Apr May Jun J u l Aug Sep Oct Nov Dec 3. Weight of rumen contents expressed as a percentage of body weight. Figure 3-10. Monthly l e v e l s of rumen f i l l and dry matter and crude p r o t e i n i n rumen contents of b l a c k - t a i l e d deer. Values are combined means f o r deer from forested and cutover areas. 176 Dry matter content of rumens from deer collected i n forested areas was higher i n a l l seasons than i n deer from cutover areas (Table 3-21). Dif-ferences were 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 (p < 0.05) except for the annual average. Increased levels of dry matter i n deer from forested areas probably i s the result of the greater proportion of shrubs and conifers i n the diet of deer from these areas (Figure 3-1), even though dry matter levels i n individual 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 result of the small sample sizes involved (Table 3-22). As expected, dry matter levels during the growing season were generally less than i n the dormant period (Figure 3-10). Rumen F i l l Seasonal and monthly levels of rumen f i l l are presented i n Tables 3-21 and 3-22 respectively. Patterns of monthly change are shown i n Figure 3-10. Average annual rumen f i l l for the 56 deer samples was 11.4 (±0.4) percent. Similar values were reported for other Cervidae including 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 virginianus (8.0 percent) (Short et a l . 1969). The s l i g h t l y higher values observed i n th i s study compared to other work with Odocoileus spp. may r e f l e c t the fact 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 levels of rumen f i l l are generally greatest. Rumen f i l l varied 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 levels of rumen f i l l for deer from forested and cutover areas combined were sta-t i s t i c a l l y different (p < 0.05) between seasons. A sim i l a r pattern of var 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 factors responsible for lower rumen f i l l i n these seasons. Short (1971) observed lower rumen f i l l i n winter i n white-tailed 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 (nonsignificantly) 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 result of greater use of shrubs and conifers by deer i n forested areas (Figure 3-1). Monthly patterns of rumen f i l l reflected the increased succulence and d i g e s t i b i l i t y of forages during the growing season, with lowest levels 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 primarily Epilobium angustifolium and very limited amounts of shrubs or conifers at th i s time (Figure 3-2). 178 Crude Protein Content Levels of crude protein i n rumen contents underwent changes of large magnitude both seasonally (Table 3-21) and monthly (Table 3-22, Figure 3-10). Levels ranged from 39.9 (±0.8) percent i n rumens of deer from cutovers i n spring to 13.7 (±0.7) percent i n deer from forested areas i n f a l l - w i n t e r . S t a t i s t i c a l comparisons of mean seasonal levels of crude protein for 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). K l e i n (1962) recorded similar levels (40.1 and 27.4 percent) of crude protein i n rumens of black-tailed deer from good and poor habitats, respectively. Crude protein content more than doubled between March and May (Figure 3-10), i n a pattern similar to that observed i n tissue of shrubs, which were important dietary components at this time (Figure 3-4). Forbs, primarily Epilobium angustifolium, became available to deer during this period, received heavy use (Figure 3-4) and probably were the major factor bringing about the increase i n crude protein levels i n rumen contents. Since levels of crude protein i n rumen content indicate both forage and microbial protein, i t i s l i k e l y that populations of microbes, which i n -crease with improved forage (Klein 1962), also contributed to the increase i n crude protein observed. Kirkpatrick et a l . (1969) documented a similar seasonal pattern i n crude protein content of white-tailed deer rumens i n the southeastern United States. Gasaway and Coady (1974) measured seasonal crude protein levels i n washed rumen contents of moose and ob-served si m i l a r patterns of seasonal change, but lower ov e r a l l levels since washing removes amino acids, soluble forage protein, and microbial protein (Klein 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 con-tent. 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). Deer from forested areas were not sampled in summer. 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 in rumen dry matter and crude protein content and rumen f i l l reflected the seasonal and monthly changes which occurred in food habits and in nutrient levels in forage plants. The degree of change occurring in rumen f i l l and dry matter content was rela-tively minor compared to changes in crude protein content, which reflected higher protein levels in forage and probably also the response of micro-bial 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 cut-overs as a result of differences in 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 in 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 f a l l . SUMMARY - CHAPTER III Treating the related areas of food habits, characteristics of forage plants and rumen characteristics together in this chapter resulted in 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 feeders, utilizing forages as they became available. 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 in spring as new plant tissue became available and in 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 in 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 avail-able. 5) Shrubs, conifers and lichens made up substantially more of the diet of deer from forested than cutover areas. Forbs were the largest dietary component in deer from cutover areas in a l l seasons. 182 6) Reduced availability of forage in fall-winter was reflected in the reduced number of species present in rumens of deer col-lected in this period. 7) The observation that forbs are of high importance is consistent with the findings of Gates (1968) who worked in central Vancouver Island. 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 de-crease in cell contents, crude protein and dry matter digesti-bility in most species. 3) Ferns and lichens presented exceptions to the pattern of de-creased 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 in forested and cutover areas were not observed; probably 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 increased beyond expected levels as proportion of Alectoria 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 of variation in rumen characteristics observed were consistent with literature 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 nutri-tious 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 compo-sition of forage plants. 186 LITERATURE CITED Ammann, A.P., R.L. Cowan, CL. 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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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. Effect of inoculum source on in vitro digestion of deer foods. J. Wildl. Manage. 40:301-307. Pearson, H.A. 1969. Rumen microbial ecology in mule deer. Appl. Microbiol. 17:819-824. Pearson, H.A. 1970. Digestibility trials: in vitro techniques, pp. 85-92 in 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. 1971. Rumen characteristics of red deer, fallow deer, and roe 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 in vitro and in 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 white-tailed 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 in 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 in 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. Selected nutrients in mule deer browse plants. Ecology 47:222-229. 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 CE. Boyd. 1969. Variations in rumino-reticular 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. J. Wildl. Manage. 12:109-110. 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 its 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. Gill 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 characteristics and their selection by black-tailed deer. Levels of VFA in 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 values in most forages occurred in summer and slightly followed maximum levels of crude protein and dry matter digestibility. 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 in part on the degree to which they are converted into a chemical form usable as an energy source by the animal. In deer and other ruminants, microbial fermentation of carbohydrates in the rumen results in the formation of volatile fatty acids (VFA) which are metabolized to yield energy. Quantification of VFA produced during in vitro fermentation by microorganisms from deer rumens should provide a relative measure of the energy 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 of energy in major forage species. 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 require-ment 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. Individual VFA's yield different caloric values upon metabolic oxidation, depending on their molecular structure. These values are constant for an individual acid and can be calculated for a VFA mixture to provide a measure of its energy value. 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 but quantities present provide 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 al. 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 produc-tion 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 fer-mentation in moose (Gasaway and Coady 1974). In white-tailed deer in summer Short (1975) observed 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 al. 1966). Diets containing readily-digestible nutrients result in increased levels of propionic, butyric or higher acids and lower levels of acetic acid than low quality diets (Short 1963, Ullrey et al. 1972). Under these conditions energy production is 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 al. (1973). In the latter study, the zero-time rate of fermentation was determined and provided an indication of rates of VFA production in 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. A 20-ml sample of the fer-mentation fluid was decanted into a vial, 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 con-tribution of the inoculum. VOLATILE FATTY ACID DETERMINATION The procedures described by Alio et al. (1973) were employed with minor changes. Quantitative analyses to determine total amounts of VFA present were conducted on wet digesta samples. 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-tillate was collected in an ice bath and titrated with 0.01 N NaOH. Con-centration of VFA was indicated by a pH change associated with the end-point 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. The liquid sample was centrifuged at 20,000 G for 15 minutes. Supernatant was de-canted and analyzed in an Aerograph model 204 gas chromatograph using a flame ionization detector and He as the carrier gas. The chromatograph was equipped with a 180 x 0.3 cm stainless steel column packed with 10 percent SP-1200 and 1 percent H3PO4 coated on 80/100 chromosorb W-AW. Proportions 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 fermenta-tion of individual forage plants were conducted following the method of Alio et al. (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. Total concentration is calculated as the sum of the concentrations of the individual acids. Net production for individual forage species was 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. Rumens of the 24 animals collected for the in vitro digestibility and VFA production trials were used. 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 first 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 in kilocalories per mole of acid as follows: acetic (Cg) - 209 propionic (C3) - 367 butyric (C4) - 524 isobutyric (C4) - 524 valeric (C5) - 628 isovaleric (C5) - 628 Total quantities of VFA and percentage of individual VFA's produced in 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 metab-olic needs of the animal on a 24-hour basis (Alio et al. 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 fermenta-tion rate t r i a l . The tissue was washed and excess water removed prior to weighing. 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 fer-mentation 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 avail-able 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 col-lection 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. All 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 i n i t i a l 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 popu-lations may have been lower than in summer when the proportion of new foliage in 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 levels of VFA production and associated calo r i c values for forage types collected in forested (F) and cutover (C) areas. Net VFA Produced Caloric Value N (mg/100 ml) (kcal/0.3 g) Season -Forage Type F C F+C F C F+C F C F+C Spring Shrubs 24 24 48 760.7a (187.7) 2 750.98 ( 84.5) 755.8 (144.1) 3.3a (0.8) 3.3a (0.4) 3.3 (0.6) Conifers 22 22 44 723.7a ( 49.7) 711.3a ( 58.4) 717.5 ( 53.9) 3.1a (0.2) 3.1a (0.2) 3.1 (0.2) Lichens 8 - - 477.9 b ( 61.5) - - 2.1 b (0.2) - -Forbs - 8 - - 794.4a (142.9) - - 3.33 (0.6) -Ferns 16 16 32 592.9 b (139.5) 633.3b ( 97.6) 613.1 (120.2) 2.6C (0.6) 2 : 7 b (0.4) 2.7 (0.5) Summer Shrubs 19 20 39 798.7 a b 697.8a 746.9 3. 4ah 3. 0 a 3. .2 (300.0) (215.1) (261.5) (1. .3) (0. • 9) (1. • 1) Conifers 16 16 32 901.9° 798.0'1 849.9 3. ,8a 3. ,4a • 3. .6 (288.2) (148.4) (231.6) (!• .1) (0. .6) . (0. .9) Lichens 8 _ _ 610.4b - - 2. ,7b (189.6) (0. • 8) Forbs - ' 8 _ 1173.6b - 4. ,9b (231.4) (1. .0) Ferns 8 8 16 704.5 a b 3t787.8 a 746.2 3. ^ab T3. ,5a 3. .3 ( 66.6) ( 46.0) ( 70.0) (0. '3) (0. .2) (0. 3) Table 4-1. Continued. Season -Forage Type N Net VFA Produced (mg/100 ml) Caloric Value (kcal/0.8 g) F C F+C F C F+C F C F+C Fall-Winter Shrubs 44 44 88 561.8° (278.2) 576.0a (308.6) 568.9 (292.2) 2.4° (1.2) 2.4° (1.3) 2.4 (1.3) Conifers 36 36 72 445.5 b (115.9) 487.0° (136.6) 466.2 (127.5) 1.8b (0.5) 2.0° (0.6) 1.9 (0.5) Lichens 12 - - 262.0° (166.8) - - 1.1° (0.7) -Forbs - 4 - - 537.4 a b ( " ) - - 2.2 a b ( " ) -Ferns 20 20 40 316.7° ( 52.5) 348.8b (121.8) 332.8 ( 94.0) 1.4° (0.2) 1.5b (0.5) 1.4 (0.4) Annual Shrubs 87 88 175 668.4a (280.9) 651.4° (255.3) 659.8 (267.7) 2.9° (1.2) 2.8° (1.1) 2.8 (1.2) Conifers 74 74 148 626.9a (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 b (210.9) - - 1.8b (0.9) - - ' Forbs -" 20 - • - 894.7b (301.9) ' -' 3.7b (1.3) •-Ferns 44 44 88 487.7 b (187.6) 532.1° (204.5) 509.8 (196.4) 2.1 b (0.8) 2.3° (0.9) 2.2 (0.9) Walues i n a column with a common superscript l e t t e r (a, b, c) are not d i f f e r e n t at p < 0.05 level as determined by analysis of variance and Scheffe's test. 2Standard d e v i a t i o n . S i g n i f i c a n t difference between VFA or c a l o r i c value i n forested or cutover indicated as t (p < 0.05) as determined by analysis of variance; Significance indicator i s beside the greater value. 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 in 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 in 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 dif-ferent in a l l seasons, with greatest values occurring in summer (Table 4-2). Since i t was difficult 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 in the plant in 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). Table 4-2. S t a t i s t i c a l comparisons of seasonal l e v e l s of VFA production and associated c a l o r i c values f o r forage types c o l l e c t e d i n forested (F) and cutover (C) areas. Forage Type - Season N Net VFA produced (mg/100 ml) Cal o r i c Value (kcal/0.8 g) F+C F+C F+C Shrubs Spring 24 24 48 760, .7 3 1 750 .9 a 755 .8 3. ,3 a 3 .3 a 3. .3 (187 • 7 ) 2 ( 84 .5) (144 • 1) (0. .8) (0 • 4) (0. 6) Summer 19 20 39 798 .7 a 697 . 8 a b 746 .9 3, ,4a 3 . o a b 3. .2 (300 • 0) (215 .1) (261 • 5) (1. .3) (0 • 9) (1. 1) Fall-Winter 44 44 88 561 .8 b 576 .o b 568 .9 2, ,4b 2 .4 b 2. .4 (278 • 2) (308 • 6) (292 • 2) (1. .2) (1 .3) •Cl. 3) Annual 87 88 175 668 .4 651 .4 659 .8 2, .9 2 .8 2, .8 (280 • 9) (255 • 3) (267 • 7) (1 • 2.) (1 • 1) (1. .2) Conifers Spring 22 22 44 723. 7 a 711. ,3 3 717 .5 3. l a 3. 1 3.1 ( 49. 7) ( 58. 4) ( 53 • 9) (0. 2) (0. 2 ) 3 (0.2) Summer 16 16 32 901. 9 b 798. ,o b 849 .9 3. ,8b 3. 4 a 3.6 (288. 2) (148. .4) (231 • 6) (1. 1) (0. 6) (0.9) Fall-Winter 36 36 72 445. 5 C 487. ,o c 466 .2 1. ,8C 2. o b 1.9 (115. 9) (136, • 6) (127 • 5) (o. .5) (0. 6) (0.5) Annual 74 74 148 626. 9 620, .9 623 .9 2. .7 2. 6 2.6 (244. 6) (180 • 7) (214 • 3) (1. .0) (0. 8) (0.9) Table 4-2. Forage Type - Season N F+C Net VFA produced (mg/100 ml) F+C Ca l o r i c Value (kcal/0.8 g) F+C Lichens Spring 8 477. ,9a 2.1a -( 61. 5) (0.2) Summer 8 610. ,4a 2.7a -(189. 6) (0.8) Fall-Winter 12 262. ,ob l . l b -(166, • 8) (0.7) Annual 28 423, .3 1.8 -(210 • 9) (0.9) Forbs Spring 8 - 794.4a 3. 3 a (142.9) (0. 6) Summer 8 _ 1173.6b 4. 9 b (231.4) (1. 0) Fall-Winter 4 _ 537.4C 2. 2 C ( " ) ( -• ) Annual 20 894.7 3. 7 (301.9) (1. 3) Table 4-2. Forage Type - Season Net VFA produced (mg/100 ml) Calor i c Value (kcal/0.8 g) F+C F+C F+C Ferns Spring 16 16 32 592.9 a 633.3 a 613.1 2.6 a 2.7 a 2.7 (139.5) ( 97.6) (120.2) (0.6) (0.4) (0.5) Summer 8 8 16 704.5 b 3t787.8 b 746.2 3.1 b T3.5 b 3.3 ( 66.6) ( 46.0) ( 70.0) (0.3) (0.2) (0.3) Fall-Winter 20 20 40 316.7° 348.8 C 332.8 1.4C 1.5 C 1.4 ( 52.5) (121.8) ( 94.0) (0.2) (0.5) (0.4) Annual 44 44 88 487.7 532.1 509.8 2.1 2.3 2.2 (187.6) (204.5) (196.4) (0.8) (0.9) (0.9) Values i n a column with a common superscript l e t t e r (a, b, c) are not d i f f e r e n t at p < 0.05 l e v e l as determined by analysis of variance and Scheffe's t e s t . 2Standard deviation. Significant difference between VFA or c a l o r i c value i n forested or cutover indicated as t (p < 0.05) as determined by analysis of variance; Significance i n d i c a t o r i s beside the greater value. 209 Caloric value and production of VFA from forbs were statistically differ-ent 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 its 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 pre-sented 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 levels of VFA production and associated c a l o r i c values for forage species collected i n forested (F) and cutover (C) areas. Net VTA Produced C a l o r i c Value N (mg/100 ml) ; (kcal/0.8 g) F C F+C F C "F+C F C F+C Shrubs Gaultheria shallon Spring 8 8 16 540.3 a i ( 39.9) 2 t 3674.2 a (26.0) 607.3 a ( 76.4) 2.3 a (0.1) +2.9a (0-2) 2.6 a (0.3) Summer 8 8 16 632.7 a (203.4) 599.3 a (199.2) 616.0 a (195.2) 2.6 a (0.8) 2.5 a (0.8) 2.6 3 (0.8) F a l l -Winter 12 12 24 384.0 b (105.4) 389.6 b (109.1) 386.8 b (104.9) 1.6 b (0.4) 1.6 b (0.4) 1.6 b (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 Spring 8 8 16 +908.4a (163.6) 728.8 a ( 62.2) 818.6 a (151.3) +3.9a (0-7) . 3.2 a (0.2) 3.6 a (0.6) Summer 7 8 15 875.8 a (390.1) 697.6 a (230.0) 780.8 a b (316.3) 3.8 a (1.7) 3.0 a (1.0) 3.3 a t (1.4) F a l l -Winter 16 16 32 650.7 a (322.5) 592.9 a (302.6) 621.8 b (309.0) 2.8 a (1-4) 2.5 3 (1-3) 2.7 b (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) Vaocinium parvifolium Spring 8 8 16 833.3 a ( 31.2) 849.8 a ( 22.5) 841.5 a ( 27.6) 3.7 a (0.1) 3.7 a (0.1) 3.7 a (0.1) Summer 4 4 8 995.7 a C - ) 894.9 a ( - ) 945.3 a ( 53.9) 4.3 a ( - ) 3.9 a ( - ) 4.1 a (0.2) F a l l -Winter 16 16 32 606.2 b (271.8) 699.0 a (358.5) 652.6 b (316.5) 2.6 b (1.2) 3.0 a (1.6) 2.8 b (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) 211 Table 4-3. Continued. Net VTA Produced C a l o r i c Value N (mg/100 mL) (kcal/0.8 g) F C F+C F C F+C F C F+C Conifers Pseudotsuga menziesii Spring S 8 16 T758.73 ( 19.7) 713. l a ( 44.9) 735.9a ( 41.0) t3.3 a (0.2) 3.1a (0.1) 3.2a (0.2) Summer 4 4 8 958.6b ( - ) 824.9a ( - ) 891.7b ( 71.4). 4.0b ( - ) 3.5a ( - ) 3.7b (0.3) F a l l -Winter 12 12 24 465.7C ( 89.3) t585.9b (136.0) 525.8C (128.2) 1.9C (0.4) T2.4b (0.6) 2.2G (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 plicata Spring 8 8 16 717.7a ( 35.9) 733.9a ( 73.9) 725.8a ( 56.7) 3.1a (0.1) 3.2a (0,3) 3.2a (0.2) Summer 8 8 16 677.l a (173.5) 710.4a (159.4) 693.7a (161.9) 2.9a (0.7) 3.1a (0.7) 3.0a (0.7) F a l l -Winter 12 12 24 415.8b (138.7) 431.l b ( 71.1) 423.4b (108.1) 1.8b (0.6) 1.9b (0.4) 1.8b (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 Spring 6 6 12 684.9a ( 64.6) 678.7a ( 42.0) 681.8 ( 52.1) 2.9a (0.2) 2.9a (o ' . i ) 2.9a (0.2) Summer 4 4 8 1294.7b ( - ) 946.5b ( - ) 1120.6 (186.2) 5.3b ( ". ) 3.9b ( " > 4.6b (0.7) F a l l -Winter 12 12 24 . 454.9C (118.4) 444.l c (140.6) 449.5 (127.2) 1.9C (0.5) 1.8C (0,6) 1.9C (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.) 212 Table 4-3. Continued. F+C Net VFA Produced (mg/100 ml) F+C C a l o r i c Value (kcal/0.8 R) 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) F a l l - 12 Winter 267.0° (166.8) l . l u (0.7) Annual 28 423.3 (210.9) 1.8 (0.9) Forbs Epilobium angustifolium Spring 8 794.4° 3.3° (142.9) (0.6) Summer 8 1173.6b 4.9 b (231.4) (1.0) F a l l - 4 537.4C 2.2 C Winter ( - ) ( " ) Annual 20 894.7 (301.9) 3.7 (1.3) 213 Table 4-3. Continued. F+C Net VFA Produced (mg/100 ml) F+C Cal o r i c Value (kcal/0.8 g) F+C Ferns Blechnum spicant Spring 8 8 16 Summer 4 4 8 510.6° ( 55.1) 766.8b ( " ) +693.6a ( 28.2) 830.8 ( " ) 602.1" (103.4) 798.8" ( 34.2) 2.2° (0.2) 3.3" ( " ) + 3.0 a (0.1) 3.6 U ( " ) 2.6" (0.4) 3.5" (0.2) F a l l - 8 8 16 301.0 C 336.3C 318.6 C 1.3C 1.4C 1.4C Winter (69.7) (107.6) (89.5) (0.3) (0.5) (0.4) Annual 20 20 40 478.0 578.1 528.0 2.1 2.5 2.3 (184.7) (219.6) (206.6) (0.8) (1.0) (0.9) Polystichum munition Spring 8 8 16 675.3a (152.2) 573.0" (106.5) 624.1" (137.4) 3.0° (0.6) 2.5" (0.5) 2.7" (0.6) Summer 4 4 8 642.3" ( " ) 744.8" ( - ) 693.5" ( 54.8) 2.8" ( - ) 3.3" ( - ) 3.0" (0.3) F a l l - 12 12 24 327.3° 357.2C 342.2° 1.4" 1.54- 1.5" Winter (37.0) (134.4) (97.6) (0.2) (0.6) (0.4) Annual 24 24 48 495.8 493.7 494.7 2.2 2.2 2.2 (193.5) (187.0) (188.3) (0.8) (0.8) (0.8) V a l u e s i n a column with a common superscript l e t t e r (a, b, c) are not d i f f e r e n t at p < 0.05 lev e l as determined by analysis of variance and Scheffe's t e s t . 2Standard deviation. 'Significant difference between VFA or c a l o r i c value i n forested or cutover indicated as f (p < 0.05) as determined by analysis of variance; Significance indicator i s beside the greater value. 214 In the conifer Thuja plicata, spring and summer caloric values were generally not different but statistical differences occurred between fall-winter and the other seasons (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 al. (1970). These investi-gators showed that simple sugar content increases during i n i t i a l stages of maturation of shoots in P. menziesii. Fermentability of tissue declines as maturation proceeds, apparently in response to increased levels of certain essential oils inhibitory to rumen microbes, and to increased structural carbohydrate content. The increase in summer VFA production over that in spring may reflect the effect of increased simple sugars. Compared to very young growth, structural carbohydrate and essen-ti a l o i l contents may not reach levels during the summer period sufficient to affect the increased fermentability brought about by increases in simple sugars. As indicated in Table 4-3, VFA production and caloric value were significantly lower in fall-winter than in other seasons in P. menziesii. Tsuga heterophylla displayed a pattern like P. menziesii, with highest caloric value in summer, lowest level in fall-winter and intermediate spring values (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. In the ferns from cutover areas, both Blechnum spicant and 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 stand-ards were included under the assumption that their chemical compositon 216 GAULTHERIA SHALLON k c a l / 0 . 8 g 5 H FORESTED k c a l / 0 . 8 g 5 t CUTOVER • — • s t a n d a r d 6 i 5 -•A -3 -2 1 1 FORESTED VACCINIUM ALASKAENSE 5 -• 4 3 2 1 CUTOVER 5 4 -3 -2 -1 -FORESTED VACCINIUM PARVIFOLIUM T 2-1 i ~ l I I i ""I 1 T-H | 1 1 V""Vml J F M A M J J A S O H D CUTOVER J F K A M J . J A S ' O N D F i g u r e 4 - 1 . Mon th ly 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 v a l u e o f f e r m e n t a t i o n p r o d u c t s o f s h r u b s p e c i e s . Va lues 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 rom each o f two dee r per month . kca l /0 .8 g 5 PSEUDOTSUGA MENZIESII .4 3.4 2 1 II FORESTED CUTOVER 11 I ' T V "I THUJA PLICATA 1 FORESTED 5 4 3 2 1 I 1 I I i i I I i I I CUTOVER / A • r, v •,,!.•!•„•, i ! t i 6' - | FORESTED 5 -4 -3 -i A TSUGA HETEROPHYLLA : j 3-I I I I i i i i . i i J F M A M J J A S 0 !i D CUTOVER i I I J 1 I I I I i i I I J F M A M J J A S O N D Figure 4-2. 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 fermentat ion products of conifer species. Values are means of dup l ica te samples fermented in rumen f l u i d from each of two deer per month. 218 kcal/0.8 g ALECTORIA SARMENTOSA 5 4 . -3 -2- -1 F O R E S T E D 48-hr fermentati on * standard o—• kcal / o.3 g 6 ^ : : l 3 -2 1 1 I I n EPILOBIUM ANGUSTIFOLIUM C U T O V E R 5 4- 4 3 2 1 F O R E S T E D BLECHNUM SPICANT 5 -• 4 -3 -2 4 1 I I I I I I I I I 1 I C U T O V E R POLYSTICHUM MUNITUM 5 4 3 2 4 1 F O R E S T E D i I I i I I I I I i I I J F M A M J J A S O N D 5 i 4 3 2 1 C U T O V E R I I I I I I I I I J F M A M J J A S O N D Figure 4 - 3 . Monthly patterns of v a r i a t i o n i n c a l o r i c value of fermentation products of l i c h e n , forb and fern species. Values are means of duplicate samples fernenteu i n rumen f l u i d from each of 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 was due to changes in composition of the species being tested or in the fermentation capacity of the rumen microbes. 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. In G. shallon, caloric value of the standard sample closely paralleled 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 respon-sible 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 from longer fermentation, a sample was fermented for an additional 24 hours (total 48 hours) each month. Caloric value of products of these 48-hour fermentations are displayed in Figure 4-3. During 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 com-pared statistically in Table 4-4. Epilobium angustifolium and the Vaccinium spp. ranked high in a l l seasons while A. sarmentosa and Gaultheria shallon ranked consistently low in 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 produc-tion. Generally, forages containing high amounts of readily fermentable nutri-ents 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 al. 1969, Ullrey et al. 1972). In poorly digested forages, not only is production of acetic acid, with its low caloric content in-221 Table 4-4. S t a t i s t i c a l comparisons of c a l o r i c values (kcal/0.8 g dry matter) of fermentation products of i n d i v i d u a l forage species. Values are seasonal and annual means f o r forested and cutover areas combined. SPRING VAPA1 3.7 2 3.6 3.3 3.2 3.2 2.9 2.7 2.6 2.6 2.1 ' / / / / / / / / / / / / / / / / / / / / /  VAAL EPAN PSME THPL TSHE POMU BLSP . GASH .• ALSA SUMMER EPAN 4.9 / / / / TSHE 4.6 FALL-WINTER VAPA VAAL 2.8 2.7 ANNUAL VAPA 4.1 EPAN 2.2 ///// PSME 3.7 PSME 2.2 \\\\ BLSP 3.5 VAAL 3.3 POMU 3.0 THPL 3.0 ALSA 2.7 GASH 2.6 TSHE 1.9 THPL 1.8 GASH 1.6 POMU 1.5 .BLSP 1.4 ALSA 1.1 •////// w w w w w w • . * . * . • EPAN VAPA VAAL PSME TSHE THPL BLSP POMU GASH ALSA 3.8 3.2 3.1 2.8 2.6 2.5 2.3 2.2 2.2 1.8 1 F o r a g e 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 as f o l l o w s : SHRUBS GASH = Gaultheria shallon VAAL = Vaocinium alaskaense VAPA = V. parvifolium CONIFERS ///,PSME = Pseudotsuga menziesii THPL = Thuja plicata TSHE = Tsuga . LICHEN ALSA = Alectoria sarmentosa heterophylla FORBS EPAN = Epilobium angustifolium FERNS s\\\BLSP = Blechnum spicant POMU = Polystichum munition 2 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) 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 . 2 2 2 GAULTHERIA SHALLON Percent Composition Percent kcal/0.8 g Composition (8) (8) (12) VACCINIUM ALASKAENSE (8) (8) (12) 100 T| 80 60 40 20 100 -| 80 4 60 40 -J 20 •FORESTED 5 4 3 »- 2 1 100 80 60 40 20 1 CUTOVER - A -(8) (7) (16) VACCINIUM PARVIFOLIUM FORESTED - 5 - 4 - 3 - 2 - A — -O-100 , 80 60 40 20 T (8) - A - D (4) T T - A - O I (8) (8) (16) CUTOVER - A -• (16) Spring Summer Fall-Winter (8) (4) (16) Spring Summer Fall-Winter 5 4 3 1-2 1 3 2 'VFA are as follows: C 2 = acetic acid, C3 = propionic acid, Cu = butyric and isobutyric acids, Other = valeric, isovaleric and higher acids, 2 * = caloric value of VFA's produced in kcal/g. 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 Percent Composition PSEUDOTSUGA MENZIESII Percent kcal/o . 8 g Composition (8) (4) THUJA PLICATA 100 -• 80 60 -| 40 20 FORESTED 80 -I 60 40 20 A -D -(8) FORESTED - A - D (8) (12) (6) (4) (12) Spring Summer Fall -Winter 5 •- 4 3 2 V l r 6 5 4 3 h i 100 80 -60 -40 -20 " CUTOVER A -D— - A -1 - i (8) (8) TSUGA HETEROPHYLLA 100 80 60 40 20 * - A (12) CUTOVER r 5 4 3 2 1-1 3-1 - 5 -4 -3 -2 -1 I I (6) (4) (12) Spring Summer Fall-Winter 'VFA are as follows: C2 = acetic acid, C3 = propionic acid, Ci, = butyric and isobutyric acids, Other = valeric, isovaleric and higher acids. 2 * = caloric value of VFA's produced in kcal/g. 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 ALECTORIA SARMENTOSA Composition 1 0 0 l FORESTED 80 60 -40 -1 \ 2 0 ' C 3 A _ Cl* A — 1_.Other a--A— FORESTED Pe r c en t kcaV 0.8 g CaTposition 5 100 S- 4 EPILOBIUM ANGUSTIFOLIUM -A * 3 Sk 2 1 CUTOVER SO -6 0 -4 0 -2 0 -(8) (8) (12) A ' -A — A D • — - • (8) (4) ' (8) BLECHNUM SPICANT 1 0 0 8 0 6 0 4 0 2 0 A -a-CUT0VE.R -A - A (8) . (8) (4) ( 8 ) (4) (8) k c a l / 0 . 8 g s - 5 POLYSTICHUM MUNITUM 1 0 0 8 0 6 0 4 0 2 0 FORESTED Spring Summer Fal1 -Winter Spring Summer Fal 1 -yiDl§£ . :VFA are as fo l l o w s : C 2 = a c e t i c a c i d , C 3 = p r o p i o n i c a c i d , 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 higher acids. 2 * = c a l o r i c value of VFA's produced i n kcal/g. Figure 4-6. Seasonal VFA composition and c a l o r i c values of fermentation products of l i c h e n , forb and fern species. Values are means of d u p l i c a t e samples; (n) = number of 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 con-tents 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 in 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 in Table 4-5. Variables selected for correlation analysis were those for which nutritional significance is 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 in the rumen is influenced by a variety of factors, including sampling time (Skeen 1974), which was not well standardized in the collection of wild deer in 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. Table 4-5. C o r r e l a t i o n s o f 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 o f forage ty p e s . Only 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 annual measurements o f samples from f o r e s t e d and c u t o v e r areas combined. C o r r e l a t i o n o f : C a l o r i c v a l u e o f VFA w i t h : p e r c e n t a c e t i c a c i d p e r c e n t p r o p i o n i c a c i d 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 a c i d - d e t e r g e n t l i g n i n S p r i n g ( 1 2 ) 5 59 SHRUBS F a l l -Summer Winter Annual (14) 61 ( 9) (35) -0.34 0.87 0.35 0.78 CONIFERS F a l l -S p r i n g Summer Winter Annual (12) (10) ( 6) (28) 67 0.90 -0.93 -0.77 0.46 -0.58 FERNS 3 Annual (12) P e r c e n t a c e t i c a c i d w i t h : p e r c e n t p r o p i o n i c a c i d crude p r o t e i n d r y matter d i g e s t i b i l i t y a c i d - d e t e r g e n t l i g n i n -0.86 -0.61 -0.96 -0.79 -0.72 -0.82 -0.51 -0.67 0.37 -0.70 0.62 -0.60 -0.98 0.73 -0.85 -0.92 -0.77 0.45 -0.45 -0.92 0.77 P e r c e n t 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 dry matter d i g e s t i b i l i t y a c i d - d e t e r g e n t l i g n i n 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 *None of the 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 annual v a l u e s are p r e s e n t e d . ''Number o f measurements. -0.79 0.72 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 posi-tively 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 coni-fers in summer are not apparent. A significant negative correlation occurred between acetic acid and propionic acid percentages 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 percent-age 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 fre-quently 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 cut-over 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. These included a negative correlation between caloric value of VFA and percent propionic acid in Gaultheria shallon, Vaccinium  alaskaense, Thuja plicata and Tsuga heterophylla, The reasons for this relationship are not apparent. It may reflect the fact that fermentation of these forages results 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. Correlations of c a l o r i c content, VFA and nutrient c h a r a c t e r i s t i c s of forage species. 1 Only s i g n i f i c a n t (p < 0.05) values are l i s t e d . Correlations are for annual measurements of samples from forested and cutover areas combined. Vaccinium Tsuga Poly-Correlation of: Gaultheria Vaccinium parvi- Pseudotsuga Tlruja hetero- Blechnum stichum shallon alaskaense folium menziesii plicata phy I la spicant munitum (12) 2 (14) ( 9) ( 8) (12) ( 8 ) ( 8 ) ( 4 ) C a l o r i c value of VFA with: percent a c e t i c acid percent propionic acid -0.75 -0.62 .. .. -0.72 -0.89 crude protein .. .. .. .. .. dry matter d i g e s t i b i l i t y .. -0.54 -0.79 .. acid-detergent l i g n i n .. .. Percent acetic acid with: percent propionic acid -0.66 crude protein dry matter d i g e s t i b i l i t y 0.58 acid-detergent l i g n i n -0.74 -0.77 -0.66 -0.78 0.71 -0.94 0.72 0.98 0.75 Percent propionic acid with: crude protein -0.59 .. ... .. .. .. -0.82 dry matter d i g e s t i b i l i t y .. .. .. .. .. .. -0.88 acid-detergent l i g n i n .. .. .. .. 'No s i g n i f i c a n t correlations occurred for Alectoria sarmentosa or Epilobium angustifolium. 2Number of measurements. 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 rela-tively small number for which VFA assessments were made, i t is not pos-sible 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) as well as highest levels of use (Figure 3-1). Similarly, shrubs were highest in caloric value and in level of use in fall-winter. 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. Crude protein is extremely low in lichens but digestibility is high. Since direct nutri-tional value of lichen appears low, one could speculate that its 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 is one component. The food habits data are too variable to attempt to define a direct relationship specifically between energy content and forage pref-erence . 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 al. (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 intro-duces substantial variation, mainly related to the difficulty in main-taining an anaerobic environment (J.H. Oh, personal communication). When this variation is 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, other parameters of rumen VFA were examined. Other investigators (Prins and Geelen 1971, Short 1963, 1971, Bruggemann et al. 1968) have used the VFA concentration in rumen contents as an indicator of seasonal forage quality in wild ruminants. Research with domestic ruminants (Leng 1970, Weston 233 and Hogan 1968) has further shown that VFA production can be estimated from concentration once the relationship of these items has been estab-lished for the ruminant species of interest. Because of va r i a t i o n i n thi s relationship and the v a r i a b i l i t y associated with feeding patterns of wild ruminants, Gasaway and Coady (1974) recommend using VFA concentration as an approximate indicator 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 from a sample taken immediately after deer c o l l e c t i o n . 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 to those observed i n black-ta i l e d deer i n C a l i f o r n i a by Al i o et a l . (1973), white-tailed deer i n the southeastern U.S. by Short (1971) and moose i n Alaska by Gasaway and Coady (1974). S t a t i s t i c a l comparisons indicate VFA concentrations i n fa 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 different. 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 to a range of 7.0-13.0 mg/100 ml observed during the year i n white-tailed deer by Short (1971). These values r e f l e c t the condition of the forages seasonally available as demonstrated with sheep by Hbgan et a l . (1969) where VFA concentrations ranged from 7.6 mg/100 ml for animals on a diet of mature, high f i b r e forage to 10.4 mg/100 ml on a diet of low fi b r e forage i n early stages of growth. Skeen (1974) measured seasonal changes i n ruminal VFA concen-trations i n white-tailed deer but was not able to relate them to changes i n forage quality as indicated by levels of other nutrients. In the Table 4-7. Seasonal comparisons of VTA concentration, composition and energy value i n rumen contents of b l a c k - t a i l e d deer. Season Spring ( n ) : Concen-t r a t i o n VTA Composition 2 (mg/100 ml) a 3 13.87 (1.26) 4 60.0 (percent) 21.0 15.2 3.1 Rumen Content digesta VTA 3.6 7.4 energy (kg) (moles) (kcal) 2076.1 (733.9) ab Summer 13.48° (1.15) 62.7 20.1 15.0 2.1 5.0 10.2 2836.0 (708.5) Tall-Winter 12 8.83" (2.50) 62.6 21.3 13.3 3.0 5.2 6.6 1847.6 (480.7) 1Number of deer. 2 I n d i v i d u a l acids: C 2 = a c e t i c , C 3 = propionic, C 4 = butyric and is o b u t y r i c , C 5+ = v a l e r i c , i s o v a l e r i c and higher acids 3Values i n a column with a common superscript l e t t e r are not d i f f e r e n t at p < 0.05 l e v e l as determined by multiple t - t e s t . ^Standard deviation. 235 present study, highest ruminal VFA concentration, indicating highest fermentation 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 combina-tion 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. Thus although i t is not a good indicator of 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 in 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 in 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 li t t l e influence on seasonal differences observed in ruminal energy con-tent. 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 angusti- folium, displayed highest energy contents among the forages studied. 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 i f rumen turnover times as reported in the literature occur. 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 characteris-tics of forage plants were variable. In some types or species, caloric value and propionic acid content were positively corre-lated 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 suc-cessful. This was apparently the result of being unable to maintain an anaerobic environment around the rumen coupled with variability in rumen contents associated with deer feeding patterns. 238 9) VFA concentrations in deer rumen contents at time of collection were consistent with those observed in deer by other investi-gators. Seasonal VFA concentrations followed a pattern like other measures of forage quality, i.e. peak concentrations occurred 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. Energy content, as one indicator of nutritional value, appears to influence forage selection within the overall framework defined by seasonal avail-ability. 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 its microbes. Academic Press, New York. 533 pp. 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. Rumen characteristics of red deer, fallow deer, and roe deer. 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 in 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 CE. 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 require-ments 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 avail-ability and quality, to physiological demand associated with the repro-ductive 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 con-dition of black-tailed deer collected at monthly intervals for one year. Levels of blood urea nitrogen (BUN) were determined to assess their rela-tionship to protein-energy levels in the diet and to annual weight gain and loss patterns. Fluctuations in weight were greater in male than females; f a l l was 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-ti 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. BUN and rumen f i l l were negatively correlated in-directly 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 urea-nitrogen in blood respond on a shorter-term basis to changes in forage protein levels. Collection of animals for in vitro trials provided an opportunity to examine selected measures of carcass fat and blood urea-nitrogen 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. Most work has involved direct or indirect measures of carcass fat. 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 deter-mine 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 deer during a mild and a severe winter. Significantly-different 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 its 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 a good measure of condition in "fat" white-tailed deer but was of lesser value as condition declined, apparently because of differential rates of depletion of kidney fat compared to fat in other locations. Anderson et al. (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 com-bined 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 al. (1972) who suggested its 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 al. 1974). Seal et al. (1972) observed this relationship for white-tailed deer as did Houston (1969) for Shiras moose (Alces alces). 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 in the diet and by catabolism of body protein. In captive white-tailed deer fawns, Buckland (1974) observed that high levels of dietary protein significantly in-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 al. (1968) and Teeri et al. (1958) observed ele 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 in remote locations.were taken in the field. These are considered live weights as shooting resulted in 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 trials. 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 its points of attachment to the organs and body wall, and its 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 its two thickest points on its 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 digest-ib 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 to a lesser degree for food habits and body condition assessments. Thus, sample sizes are not as high as they would have been if 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 difficult 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). When these patterns of weight change are examined a dis-tinct trend is evident and is comparable to that reported by others working with species of Odocoileus (Brown 1961, Wood et al. 1962, Robinette et al. 1973, and Short et al. 1969). Table 5-1. Seasonal patterns i n selected morphological parameters and measures of body condition i n male and female b l a c k - t a i l e d deer. Field-Dressed Mesentery Kidney Fat Season n Live Weight Weight Weight R a t i o 1 Back Fat Weight Index 2 - (kg) — — (kg) - (mm) - - (g) " Spring Males 4 ' 36.8 (11.4) 3 25.5 ( 6.9) 0.70 (0.05) 0.5 (0.0) 33.9 ( 18.3) 1. ,1 (0.4) Females 9 41.1 ( 8.4) 28.1 ( 5.9) 0.69 (0.04) 1.75 (2.4) 85.2 ( 66.8) 1. ,2 (0.1) Males and Females 13 a39.8 ( 9.1) 4 a27.3 ( 6.1) a0.69 (0.04) a1.3 (2.0) a68.1 ( 59.8) a l . ,1 (0.1) Summer Males 5 44.3 (16.3) 33.9 (12.1) 0.71 (0.01) 4.9 (8.8) 243.0 (338.7) 1, .4 (0.6) Females 10 41.3 (10.2) 30.0 ( 3.3) 0.68 (0.04) 2.8 (3.2) 151.8 ( 93.1) 1. .3 (0.3) Males and Females 15 a42.2 (11.9) a31.5 ( 7.7) . a0.69 (0.04) a3.4 (5.1) b182.2 (200.7) .3 (0.4) Fall-Winter Males 21 35. .9 (16.3) 24. .8 (16.2) 0.69 (0.3) 0.5 (0.0) 44.4 ( 50.0) 2. .1 (1.6) Females 29 40. .5 ( 7.7) 27. .1 ( 6.1) 0.67 (0.67) 4.3 (5.8) 132.6 (119.3) 1. .6 (1.0) Males and Females 50 a39, .2 ( 9.6) a26. .0 (13.0) a0.68 (0.06) a3.3 (5.2) a b108.2 (111.4) b l . .8 (1.2) 1Weight r a t i o = f i e l d dressed weight / l i v e weight 2Kidney f a t index = weight of kidneys plus weight of f a t / weight of kidneys. ^Standard deviation. 4Combined male and female means sharing a common superscript (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 at p < 0.05 as determined by analysis of variance and Scheffe's t e s t . 250 Weight (kg) 50 40 30 L - | 20 l i v e weight • j N, / ; ; 0 X ,o- .-C field-dressed weight X) 50 40 &- 30 Mesentery Weight (g) 400 -a 300 -H 200 100 back fat depth / J mesentery weight « Back Fat Depth (mm) 12 H- 9 B- 6 r 3 kidney wt. + fat wt. kidney wt. Kidney Fat Index 3 Weight Ratio CV * " weight r a t i o \ _ A . ^ k i d n e y fat index month: J F M A M J J A S O N D n : - 3 5 7 5 6 6 3 1 0 1 2 3 4 field-dressed 1 weight l i v e weight Figure 5 - 1 . Monthly patterns of v a r i a t i o n in selected morphological parameters and measures of body condition i n bl a c k - t a i l e d deer of mixed ages and sex. 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) and amounted to about 24 percent. 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 al. (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 al. 1970) and for red deer Cervus elaphus (Mitchell et al. 1976). Anderson et al. (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 al. (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 black-tailed 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 its 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. Little digestible energy is available for fat production. 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 (Table 5-1) and showed l i t t l e variation on a year-long basis. 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 in 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 its 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 con-dition 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 al. 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 essen-tially absent during spring and fall-winter, reflecting the utilization of depot fat associated with increased activity and reduced food intake during the rut. Back fat in females was not depleted to the extent i t was 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 al. (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 fat was absent i n the current study probably reduces i t s u t i l i t y as a condition indicator. Mesentery weight was s i g n i f i c a n t l y higher i n summer then i n spring for male and female black-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 fat than males i n a l l seasons except summer, probably since does were lacta 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 fat weight closely followed the pattern of back fat depth with which i t was closely correlated (Table 5-2). Actual weights varied from 24.8 (± 2.0) g i n A p r i l , i n which no depot fat was v i s i b l e , to 341.5 (± 74.5) g i n October. Mesentery fat weight was s i g n i f i c a n t l y correlated to both l i v e weight and field-dressed weight (Table 5-2) with the highest r values, 0.88 and 0.91, respectively, i n summer when weights were highest. Recognizing the small sample size and the observation that mesentery fat weight undergoes substantial v a r i a t i o n throughout the year, i t s t i l l appears to have potential as an indicator of body condition. More work with larger samples i s needed to determine i t s u t i l i t y . Seasonal levels of KFI are presented i n Table 5-1. Significant d i f f e r -ences (p < 0.05) were observed beween spring and f a l l - w i n t e r ; summer levels were not different from the other two seasons. Highest average KFI for male and female deer combined occurred i n the f a l l - w i n t e r period and generally coincided with the peaks i n other fat measures and body weights as displayed i n Figure 5-1. Other investigators (Riney 1955, Taber et a l . 1959, M i t c h e l l 1976) have found KFI suitable as an indicator 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) Live weight with: field-dressed weight mesentery weight kidney fat index 0.97 0.73 0.61 0.98 0.88 0.83 0.95 0.52 0.42 Field-dressed weight with: mesentery weight kidney fat index 0.77 0.62 0.91 0.89 0.52 0.55 Mesentery weight with: kidney fat index back fat depth 0.91 0.92 0.93 0.85 0.88 0.80 Kidney fat index with: back fat depth 0.91 0.89 0.91 256 observed statistically significant seasonal changes in kidney size of caribou points out some previously unrecognized problems with this tech-nique. The assumption employed in 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 in another physi-cal attribute such as body size. That a similar problem occurs in deer is shown by Dauphine* s calculation of the data of Taber et al. (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 dis-tribution 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 in kidney weight before i t is 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. All of the relationships examined were significant (p < 0.05) and correlation coefficients were high in nearly a l l cases. This observation is similar to those of Anderson et al. (1972) who interpreted the significant correlation to suggest that the fat indices chosen were fairly synchronous on a year-long 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 is not clear since month-to-month variation in a l l variables during summer appeared as great as in other seasons. 257 Blood-Urea Nitrogen (BUN) Seasonal levels of BUN in blood serum of black-tailed deer are listed in Table 5-3. Values are for a l l deer collected in each season as statisti-cal comparisons indicated there were no differences (p < 0.05) between age or sex classes. Seal and Erickson (1969) also noted this lack of difference due to sex and age in white-tailed deer. Statistically sig-nificant (p < 0.05) differences in BUN occurred between a l l 3 seasons (Table 5-3). Skeen (1974) noted significant seasonal differences in BUN in wild white-tailed deer as did Seal et al. (1972) working with pregnant white-tailed deer in captivity. A direct relationship between levels of protein in forage and BUN concen-tration 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) related in summer (r = 0.72) and fall-winter (r = 0.75) but not during spring. The reason for the sharp decline in BUN in June, compared to the relatively minor reduction in ruminal crude protein is not apparent. There may have been some relationship to reproductive state as 3 of the 4 animals in the sample were adult females that 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. Le Resche et al. (1974) ob-served significantly higher BUN levels in cow moose with calves compared 258 Table 5-3. Seasonal l e v e l s of blood urea nitrogen (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. Season n BUN n Rumen Crude Protein (mg/100 ml) (%) Spring 10 25.8 a i (8.8) 2 12 38.7 a (4.2) Summer 11 15.9 b (6.1) 14 27.7 b (9.3) Fall-Winter 26 7.4 C (7.1) 27 17.4° (5.3) denotes 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 analysis of variance and Scheffe's t e s t . Means within a column having a common superscript (abc) are not d i f f e r e n t (p < 0.05). 2Standard deviation. 259 Figure 5 - 2 . Monthly levels of blood-urea nitrogen and ruminal crude protein in black-tailed 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 in May corresponds to the peak protein level in most forage species (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. The further declines in BUN and 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. Buckland (1974) observed low (r < -0.5) but significant (p < 0.05) negative correlations between crude fibre in the rumen and BUN during f a l l and winter in white-tailed deer in the southeastern United States. Positive correlations (r < 0.5) were noted for BUN 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. Skeen (1974) working with wild male white-tailed deer in the 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 is 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 con-verted to urea. Most urea is subject to urinary excretion but most rumi-nants including deer (Robbins et al. 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. Hebert (1978) recorded that tissue catabolism increased BUN from 8.5 to 24.2 mg/100 ml in bighorn sheep maintained on a diet of 2-3 percent crude protein for a 4-month period. de Calesta et al. (1977) measured the levels of BUN in 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 in the other groups. de Calesta (1977) speculated 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 al. (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 levels in black-tailed deer in the present study ranged from 4.0 (±0.5) in February and December to 30.0 (± 3.4) mg/100 ml in May (Figure 5-2). 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 al. (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 in weight and other measures of condition tended to be 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, lacta-tion 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 weight of mesentery fat were closely correlated; mesentery 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 correlation of KFI, mesentery fat and depth of back fat with each other were consistently significant suggesting these measures are fairly synchronous on a year-long basis. BUN concentrations observed in the study compared closely with those reported for other North American cervids. Seasonal differences in BUN levels were statistically signifi-cant; highest levels occurred in 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 in 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 and BUN were negatively correlated, indirectly indi-cating a decline in BUN with increased fibre and reduced digestibility of forage plants. 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 indica-tion that catabolism was responsible for elevated BUN at any time during the year. 17) BUN is a fairly reliable indicator of level of protein intake in black-tailed deer at least at protein intake levels above that required for maintenance. Temporal patterns of variation in weights and other measures of body con-dition in black-tailed deer were seen to be related to patterns of varia-tion in nutritional value of forage plants. Kidney fat index and mesentery weight appear to have utility as condition indicators, at least at the extremes of fluctuation of body weight. 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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 in 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. Nutri-tional effects on thyroid activity and blood of white-tailed deer. J. Wildl. Manage. 36:1041-1052. Short, H.L. 1975. Nutrition of southern deer in 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 arti 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. As the density of forages of high quality in the en-vironment 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 in interpreting the foraging behavior of granivores and carnivores (see reviews of Pyke et al. 1977, Krebs 1978). Ruminants, however, invariably depart from the predictions of current theory; spe-cifically they ingest more forage species of lower quality than is pre-dicted. 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 depar-ture 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 is 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 black-tailed 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 in 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 im-portance 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 cut-overs 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 con-sidered (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 forages3 consumed by black-tailed deer in forested and cutover areas. Spring Summer — Fall-Winter — Annual Forage Characteristic Forested Cutover Forested Cutover Forested Cutover Forested Cutover Energy content (kcal/0.8 g) 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 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 - Epilobium angustifolium IV = 47, Rubus spp. IV = 18, Cornus canadensis IV = 15 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 = 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 condi-tion but even in the relatively mild winter of the study period condition deteriorated markedly (Figure 5-1). Data of Jones (1975) document that deterioration in condition is 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 adja-cent second-growth forests develop a structure which will result in reduced snow depths. 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 struc-ture. 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 signifi-cant biomass of lichens will 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 suit-able stands remaining and lichens and other forms of l i t t e r f a l l will be even less effective in maintaining deer through critical periods. Severe winter conditions do not occur regularly, nor are they predict-able. 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 popu-lation 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 kills at 5- to 10-year intervals. A third alternative is to manage according to past climatic 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 critical winter range available and the rate at which second-growth forests develop and function as winter range. With regard to the latter, several areas of research beneficial to deer management are sug-gested: initially 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, depend-ing 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 develop-ment 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 second-growth forest. Determination of habitat selection patterns of deer in second-growth relative to winter weather conditions should aid in pre-dicting 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 of managing second-growth stands to provide the reduced 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 critical 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 envi-ronment. Amer. Natur. 100:603-609. Pulliam, H.R. 1975. Diet optimization with nutrient contraints. Amer. Natur. 109:765-768. 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. Ann. Rev. Ecol. Syst. 369-403. Appendix Table 1. Seasonal frequency and volume of occurrence and importance v a l u e 1 of forage 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 forested and cutover areas. Spring ( 1 3 ) 2 —• Summer3(18) — F a l l - W i n t e r (39) Impor- Impor- Impor-Fre- Impor- tance Fre- Impor- tance Fre- Impor- tance Forage quency — V o lume— tance Value quency — V o l u m e — tance Value quency Volume— tance Value Type (%) (ml) (%) Value (%) (%) (ml) (%) Value (%) (%) (m 1) (%) Value (%) Shrubs 100.0 61.8 47. 6 47.6 51.2 83.0 30.3 10.9 9.05 18.7 96.4 20 .0 . 16. 2 15. 6 35.8 Con i f e r s 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 • 4. 8 11.1 Deciduous trees - - . - - - 6.0 1.5 0.5 0.03 0.06 3.5 1 .2 1. 0 0. OA . 0.1 Lichens 34.0 t r . " - - - 28.0 4.1 1.5 0.42 0.9 .69.7 14 . 5 11. 8 8. 2 18.8 Forbs 100.0 50. 5 38. 9 38.9 41.9 83.0 117.8 42.2 35.03 72.4 47.5 20 .4 16. 5 7. 8 17.9 Ferns 68.0 5.3 4. 1 2.8 3.0 11.0 2.0 0.7 0.08 0.2 51.9 5 .5 4. 5 2. 3 5.3 L i v e r w o r t / Moss 82.0 2.1 1. 6 1.3 3.0 28.0 t r . - '- 66.8 t r . Grass/ Sedge 13.5 6.9 5. 3 0.7 0.8 17.0 t r . - - - 7.2 22 .7 18. 4 1. 3 3.0 Fungi - - - - 11.0 5.0 1.8 0.20 0.4 18.0 9 .3 7. 5 1. 4 3.2 Twigs/Bark - -. - - - - - - 8.0 . 1 .5 1. 2 • 0.1 0.2 B e r r i e s - - •'. - - - 6.0 99.0 35.5 2.13 4.4 -Equisetum 4.5 t r . - - . - - - - - 13.5 17 .5 14. 2 1. 9 . 4.4 Other 43.0 0.5 0. 4 0.2 0.2 17.0 4.7 1.7 0.29 0.6 5.4 4 .3 ' 3. 5 0. 2 0.5 Tot a l 129.9 92.9 278.9 48.37 123 .4 43. 6 . Importance value 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. 3No rumen samples were c o l l e c t e d from f o r e s t e d areas i n summer; thus summer data represent values for cutover areas only. 11 t r . = trace - volume of forage type was at or below 0.5 ml. Appendix Table 2. Seasonal frequency and volume of occurrence and importance value 1 of forage types consumed by b l a c k - t a i l e d deer collected i n forested areas. Spring ( ? ) 2 Summer (0) Fall-Winter (11) Impor- Impor- Impor-Forage Type Fre-quency (%) —Volume— (ml) (%) Impor-tance Value tance Value (%) Fre-quency (%) —Volume— (ml) (%) Impor-tance Value tance Value (%) Fre-quency (%) —Volume— (ml) (%) Impor-tance Value tance Value (%) Shrubs 100.0 92.0 70.1 70.1 70.3 100.0 22.6 28.9 28.9 37.0 Conifers 100.0 5.5 4.2 4.2 4.2 91.0 6.8 8.7 9.6 12.3 Deciduous trees - - - - - - - - -Lichens 50.0 t r . 3 - - 100.0 26.9 34.4 34.4 44.0 Forbs 100.0 18.3 13.9 13.9 13.9 27.0 2.8 3.6 1.0 1.3 Ferns 100.0 10.5 8.0 8.0 8.0 18.0 6.8 8.7 1.6 2.0 Liverwort/ Moss 100.0 4.0 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 Other 50.0 1.0 0.8 0.4 0.4 - - - - -Total 131.3 99.7 78.23 78.15 Importance value 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 divided by the sum of the importance values for a l l types. Number of rumens analyzed. 3 t r . = trace - volume of forage type was at or below 0.5 ml. Appendix Table 3. Seasonal frequency and volume of occurrence and importance value 1 of forage typ consumed by b l a c k - t a i l e d deer collected 'in-cutover areas. Spring ( l l ) 2 Summer (18) Fall-Winter (28) Impor- Impor- Impor-Forage Type Fre-quency (%) —Volume—-(ml) (%) Impor-tance Value tance Value (%) Fre-quency '(%) —Volume— (ml) (%) Impor-tance Value tance Value (%) Fre-quency (%) —Volume-— (ml) (%) Impor-tance Value tance Value (%) j c  Shrubs 100.0 31.6 24.8 24.8 25.2 83.0 30.3 10.8 9.05 18.7 92.8 17.3 10. 2 9.5 21.6 Conifers 27.0 t r . 3 - - - 22.0 14.5 5.2 1.14 2.4 89.3 6.3 3. 7 3.3 7.5 Deciduous trees - - - - - 6.0 1.5 0.5 0.03 0.06 7.0 2.3 1. 4 0.1 0.2 Lichens 18.0 t r . - - - 28.0 4.1 1.5 0.42 0.9 39.3 2.1 1. 2 4.7 10.7 Forbs 100.0 81.8 64.3 64.3 65.3 83.0 117.8 42.2 35.03 72.4 67.9 38.0 22. 5 15.3 34.7 Ferns 36.0 t r . - - - 11.0 2.0 0.7 0.08 0.2 85.7 4.3 2. 5 2.1 4.8 Liverwort/ Moss 64.0 0.14 0.1 6.4 6.5 28.0 t r . - - - 78.6 t r . - -Grass/ Sedge 27.0 13.7 10.8" 2.9 2.9 17.0 t r . - - - 14.3 45.4 26. 8 3.8 8.6 Fungi — - - - - 11.0 5.0 1.8 0.20 0.4 17.9 9.2 5. .4 1.0 2.3 Twigs/Bark - - - - - - - - - - 7.0 1.0 0. .6 0.04 0.1 Berries - - - - - 6.0 99.0 35.5 2.13 4.4 - - - — Equisetum 9.0 t r . - - - - - - - 17.9 34.5 20. ,4 3.7 8.4 Other 36.0 t r . - - - 17.0 4.7 1.7 0.29 0.6 10.7 8.7 5. ,1 0.5 1.1 Total 127.24 98.4 278.9 169.1 44.04 'importance value 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 divided by the sum of the importance values for a l l types. 2Number of rumens analyzed. 3 t r . = trace - volume of forage type was at or below 0.5 ml. Appendix Table 4. Monthly frequency, volumes and importance values 1 of forage types consumed by b l a c k - t a i l e d deer i n forested and cutover areas. January (3) 2 February (5) Impor- Impor-tance tance Frequency Volume Importance Value Frequency Volume Importance Value (%) (ml) (%) Value (%) (%) (ml) m Value (%) Shrubs 100.0 4.0 18.0 18.0 21.1 100.0 13.0 40.0 40.0 52.4 Conifers 100.0 2.0 9.0 9.0 10.5 100.0 3.8 11.7 11.7 15.3 Deciduous Trees - - - - - - - - — — Lichens 33.0 t r . 3 - - - 60.0 8.0 24.6 14.8 19.4 Forbs 67.0 10.5 47.0 31.5 36.8 40.0 3.0 9.2 3.7 4.8 Ferns 100.0 5.8 26.0 26.0 30.4 40.0 4.0 12.3 4.9 6.4 Liverwort/Moss 67.0 t r . - - - 60.0 0.67 2.1 1.3 1.7 Grass/Sedge 33.0 t r . - - - - - — — — Fungi - - - - - — — — — -Twigs/Bark - - - - - • - - — — Berries - - - - — — — — Equisetum - - - - - — — — — — Other - - - - - — — — — — Total 22.3 85.5 ' 32.5 . 76.4 - M a r c n {o) Shrubs 100.0 23.5 25.3 25.3 41.3 100.0 6.9 3.3 3.3 5.9 Conifers 100.0 6.25 6.7 6.7 10.9 100.0 14.5 6.9 6.9 12.3 Deciduous Trees 13.0 0.5 0.5 0.07 0.1 - - - - — Lichens 50.0 22.4 24.1 12.1 19.7 50.0 25.7 12.3 6.2 11.0 Forbs 63.0 9.1 9.8 6.2 10.1 67.0 25.5 12.2 8.2 14.6 Ferns 75.0 9.3 10.0 7.5 12.2 67.0 1.0 0.5 3.4 6.0 Liverwort/Moss 75.0 0.25 0.27 0.2 0.3 83.0 t r . - - — Grass/Sedge - - - - - 33.0 89.8 43.0 14.2 25.3 Fungi 12.5 t r . - - - 17.0 t r . — Twigs/Bark - - - - ' — — — — Berries - - - - — — — — -Equisetum 25.0 2.0 2.2 0.6 1.0 67.0 42.3 20.2 13.5 24.0 Other 12.5 19.5 21.0 2.6 4.2 33.0 3.25 1.6 0.5 0.9 Total 92.8 61.3 208.95 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. May (7) June (6) Impor-tance Impor-tance Frequency Volume Importance Value Frequency Volume Importance Value (%) (ml) (%) Value (%) (%) (ml) (%) Value (%) Shrubs 100.0 39.6 31.7 31.7 37.1 100.0 42.3 31.9 31.9 31.9 Conifers 57.0 2.75 2.2 1.3 1.5 17.0 t r . - - . -Deciduous Trees . - - - - - - - - - • -Lichens 14.0 t r . - - - 33.0 t r . - - -Forbs 100.0 56.4 45.2 45.2 52.9 100.0 90.3 68.1 68.1 68.1 Ferns 71.0 4.2 3.4 2.4 2.8 17.0 t r . - - -Liverwort/Moss 100.0 1.29 1.0 1.0 1.2 33.0 t r . - - -Grass/Sedge 29.0 20.5 16.4 3.8 4.4 17.0 t r . - - -Fungi - - - - - - - - - -Twigs/Bark - - - - - - - - - -Berries - - - - - - - - - -Equisetum - - - - - 17.0 t r . - - -Other 17.0 t r . - - - 17.0 t r . - - -Total 124.74 85.4 132.6 100.0 _ Atimirj f" nn -July (J) AUgUoL Shrubs 60.0 2.2 0.8 0.5 0.9 100.0 39.6 23.6 23.6 30.4 Conifers 40.0 2.75 1.0 0.4 0.7 9.0 12.5 7.5 0.7 0.9 Deciduous Trees - - - - - 9.0 1.5 0.9 0.1 0.1 Lichens 20.0 10.0 3.6 0.7 1.3 18.0 1.25 0.7 0.1 0.1 Forbs 80.0. 158.3 57.5 46.0 83.3 82.0 107.8 64.3 52.7 67.8 Ferns - - - - - 9.0 t r . - - -Liverwort/Moss 60.0 t r . - - - - - - - -Grass/Sedge 60.0 t r . - - - - - - - -Fungi - - - - - 18.0 5.0 3.0 0.5 0.6 Twigs/Bark - - - - - - - - - -Berries 20.0 99.0 36.0 7.2 13.0 - - - - -Equisetum - - - - - - - - - -Other 40.0 3.0 1.1 0.4 0.7 - - - - -Total 275.25 55.2 167.65 77.7 Appendix Table 4. Monthly frequency, volumes and importance values 1 of forage W s V consumed by b l a c k - t a i l e d deer i n forested and cutover areas, c o n t i n u e d . September (2) October (4) Frequency (%) Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Grass/Sedge Fungi Twigs/Bark Berries Equisetum Other Total Shrubs Conifers Deciduous Trees Lichens Forbs Ferns Liverwort/Moss Crass/Sedge Fungi Twigs/Bark Berries Equisetum Other Total 50.0 50.0 100.0 100.0 50.0 100.0 50.0 100.0 67.0 11.0 67.0 33.0 78.0 67.0 33.0 Impor-tance Volume Importance Value (ml) (%) Value (%) 12.0 8.0 4.0 5.1 40.0 26.7 13.4 17.0 4.0 2.7 2.7 3.4 81.8 54.6 54.6 69.3 4.0 2.7 1.4 1.8 t r . 8.0 149.8 40 4 4 11 5 3 2 6 0 6 5 7 t r . 6.3 75.9 5.3 November (9) 53.0 6.1 5.3 15.3 7.2 4.9 8.3 2.7 78.8 53.0 4.1 0. 10. 2. 3. 2.7 76.9 3.4 68.9 5.3 0.8 13.4 3.1 4.9 3.5 100.0 100.0 50.0 50.0 50.0 75.0 75.0 153.57 88.28 3.4 7.6 28.0 35.5 2.0 0.17 1.3 December (4) 4.4 9.7 35.9 45.5 2.6 0.2 1.7 4.4 9.7 17.9 22.8 1.3 0.15 1.3 Impor-tance Frequency (%) Volume (ml) (%) Importance Value Value (%) 50.0 8.5 5.5 2.8 3.2 75.0 2.0 1.3 1.0 1.1 75.0 1.0 0.7 0.5 0.6 100.0 116.9 76.1 76.1 86.2 50.0 t r . - — 75.0 0.17 0.1. 0.08 0.1 25.0 2.0 1.3 0.3 0.3 50.0 23.0 15.0 7.5 8.5 - - - - -7.6 16.9 31.1 39.6 . 2.2 0.3 2.3 77.97 57.55 Percent importance, value i s 'importance value i s the product of percent frequency of occurrence the importance value of i n d i v i d u a l types divided by the sum of 2Number of rumens analyzed and percent volume the importance values for a l l types t r . = trace - volume of forage type was at or below 0.5 ml. Appendix Table 5. Seasonal frequency, volumes and importance values 1 of the 15 forage species occurring in greatest volumes in rumens of black-tailed deer from forested and cutover areas. Spring (13)' Fre-quency (%) 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 9.0 95.5 86.5 4.5 29.5 — Volume — (ml) (%) 6.0 51.5 9.8 tr. tr. 190.2 Impor-tance Value Impor-tance Fre-Value quency Summer3(18) 3.2 27.1 5.2 0.3 25.9 4.5 52.3 0.6 49.5 8.6 66.0 37.8 19.9 13.1 25. .0 70.5 11.5 6.0 4.2 8. .0 34.0 4.0 2.1 0.7 1. .3 13.5 6.8 3.6 0.5 1. .0 4.5 33.5 17.6 0.8 1. .5 4.5 16.7 8.8 0.4 0. ,8 14.0 3.4 1.8 0.3 0. ,6 25.0 6.5 3.4 0.9 1. 7 50.0 2.7 1.4 0.7 1. 3 11.0 17.0 22.0 6.0 — Volume — (ml) (%) 3.8 28.7 1.8 94^0 318.1 1.2 9.0 0.6 29.6 'importance value is 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. Impor-tance Value 0.1 1.5 0.1 J L 8 42.8 Impor-tance Value (%) Fall-Winter (39) Fre-quency (%) Volume (ml) 67.0 24.0 7.5 5.0 11.7 67.0 13.1 4.1 2.7 6.3 22.0 12.6 4.0 0.9 2.1 28.0 4.1 1.3 0.4 0.9 78.0 114.6 36.0 28.1 65.7 50.0 7.6 2.4 1.2 2.3 11.0 2.0 0.6 0.7 1.6 6.0 10.3 3.2 0.2 0.5 11.0 1.5 0.5 0.1 0.2 0.2 3.5 0.2 4.2 Impor-tance Value Impor-tance Value 78 .5 21.5 13.5 10.6 34.3 23 .5 4.0 2.V 0.7 2.3 60 .0 1.5 0.9 0.5 1.6 76 .0 4.4 2.8 2.1 6.9 69 .5 13.2 8.3 5.8 19.0 17 .0 42.0 26.5 4.5 14.8 29 .0 3.7 2.3 0.7 2.3 50, .0 3.3 2.1 1.0 3.3 7, .0 22.7 14.3 . 1.0 3.3 11. .5 15.3 9.6 1.1 3.6 32. 0 1.9 1.2 0.4 1.3 19. 5 4.2 2.6 0.5 1.6 9. 0 17.3 10.9 1.0 3.3 41. 0 2.1 1.3 0.5 1.6 15. 5 1.1 0.7 0.1 0.3 158.8 30.5 Percent importance value Is the importance value of individual No rumen samples were collected from forested areas in summer; thus summer values are for cutover areas only tr. = trace - volume of forage type was at or below 0.5 ml. Appendix Table 6. Seasonal frequency, volumes and importance values 1 of forage species occurring in greates volumes in rumens of black-tailed deer in forested areas. Spring ( 2 )' Summer3 (0) Fall-Winter (11) Fre-quency (%) 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 — Volume — (ml) (%) Impor-tance Value Impor-tance Value (%) 100.0 80.0 55.6 55.6 65.2 100.0 12.0 8.3 8.3 9.7 50.0 tr> - - -• 50.0 8.0 5.6 2.8 3.3 50.0 3.5 2.4 1.2 1.4 50.0 8.0 5.6 2.8 3.3 50.0 13.0 9.0 4.5 5.3 50.0 10.0 6.9 3.5 4.1 100.0 5.5 3.8 3.8 4.5 100.0 A.O 2.8 2.8 3.3 144.0 85.3 Fre-quency (%) — Volume (ml) (%) Impor-tance Value Impor-tance Value (%) 100.0 21.9 23.3 23.3 37.0 18.0 2.3 2.5 0.5 0.8 45.0 0.7 0.8 0.4 0.6 73.0 4.8 5.1 3.7 5.9 100.0 24.8 26.4 26.4 41.9 9.0 6.0 6.4 0.6 0.9 18.0 1.3 1.4 0.3 0.5 18.0 2.5 2.7 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 2.5 2.7 2.2 3.5 18.0 4.3 4.6 0.8 1.3* 93.8 63.0 importance value is 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. 2Number of rumens analyzed. 'Samples were not taken from deer in forested areas in summer, ''tr. = trace - volume of forage type was at or below 0.5 ml. Appendix Table 7. Seasonal frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in cutover areas. Spring (11): Summer (18) Fall-Winter (28) Fre-quency (%) Gaultheria shallon Rubus spp. Vaccinium spp. Thuja plicata Alectoria sarmentosa Epilobium angustifolium Cornus canadensis .Blechnum spioant Grass spp. Fungi Potentilla palustris Rosa spp. Lactuoa muralis Smilacina raoemosa Rubus berries Lysitchum americanum Tsuga heterophylla Linnaea borealis Equisetum spp. Tellemia grandiflora Total 18.0 91.0 73.0 9.0 9.0 82.0 91.0 18.0 27.0 9.0 9.0 28.0 9.0 Impor-Impor- tance Fre- Impor-— Volume tance Value quency — Volume — tance (ml) (%) Value (%) (%) (ml) (%) Value 12.0 4.7 0.8 1. 7 _ _ _ _ 22.9 9.0 8.2 17.8 67.0 24.0 7.5 5.0 7.6 3.0 2.2 4.8 67.0 13.1 4.1 2.7 t r . 3 _ - 22.0 12 .6 4.0 0.9 tr. - - - 28.0 4.1 1.3 0.4 67.7 26.6 21.8 47.4 78.0 114.6 36.0 28.1 19.5 7.7 7.0 15.2 50.0 7.6 2.4 1.2 tr. _ - - 11.0 2.0 0.6 0.7 13.7 5.4 1.5 3.3 - - - -_ - - 6.0 10.3 3.2 0.2 67.0 26.3 2.4 ' 5.2 33.5 13.2 1.2 2.6 11.0 1.5 0.5 0.1 6.8 2.7 0.8 1.7 4.0 1.6 0.1 0.2 6.0 94.0 29.6 1.8 17.0 28.7 9.0 1.5 11.0 3.8 1.2 0.1 22.0 1.8 0.6 0.1 254.7 46.0 318.1 42.8 Impor-tance Value (%) 11.7 6.3 2.1 0.9 65, 2, 0.5 0.2 4.2 3.5 0.2 0.2 Fre-quency (%) — Volume — (ml) (%) 57.0 29.0 75.0 79.0 39.0 25.0 40.0 82.0 14.0 14.0 7.0 39.0 18.0 4.0 21.1 6.9 2.4 4.0 1.5 77.9 6.1 4.1 45.4 11.5 3.0 8.4 34.5 5.0 231 .8 9.1 3.0 1.0 1.7 0.6 33.6 2.6 1.8 19.6 5.0 1.3 3.6 14.9 2.2 Impor-tance Value 5.2 0.9 0.8 1.3 0.2 8.4 1.0 1.5 2.7 0.7 0.1 1.4 2.7 0.1 27.0 Impor-tance Value (%) 19.3 3.3 3.0 4.8 0.7 31.1 3.7 5.5 10.0 2.6 0.4 5.2 10.0 0.4 •importance value is the product of percent frequency of occurrence and percent volume. Percent importance types divided by the sum of the importance values for a l l types. 2Number of rumens analyzed. 3 t r . = trace - volume of forage type was at or below 0.5 ml. ce value is the importance value of individual Appendix Table 8. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest ppe volumes in rumens of black-tailed deer in forested and cutover areas. Fre-quency (%) Gaultheria sluxllon Rubus spp. Vaeeinium spp. Thuja plicata Alectoria sarmentosa Epilobium angus tifo Hum Cornus canadensis Blechr.um spicant Grass spp. Fungi Linnaea borealis Abies amabilis Dryopteris austriaca Berber-is nervosa Pseudotsuga menziesii Lobaria oregana Tsuga heterophylla T o t a l 67.0 67.0 100.0 33.0 33.0 January 2(3) 3 Volume Impor-tance Impor-tance Value 33.0 20.0 50.9 16. 8 31. 8 100.0 5.5 14.0 14. 0 26. 5 33.0 tr. -67.0 0.5 1.3 0. .9 1. .7 67.0 3.0 7.6 5, .1 9. .7 33.0 1.0 2.5 0, .8 1 .5 33.0 2.0 5.1 1 .7 3 .2 Fre-quency (ml) (%) Value (%) m 3.0 7.6 5.1 9.7 75.0 3.0 7.6 5.1 9.7 -1.3 3.3 3.3 6.3 83.5 tr." _ - - 83.5 tr. - - - 50.0 58.5 50.0 25.0 February (5) — Volume — (ml) (%) 15.7 0.3 3.8 2.2 3.2 2.0 0.5 51.6 1.0 12.8 7.2 10.5 6.6 1.6 Impor-tance Value 38.7 0.8 10.7 3.6 6.1 3.3 0.4 Impor-tance Fre-Value quency (%) (%) 57.3 1.2 15.9 5.3 9.0 4.9 0.6 39.3 52.8 16. ,5 0. 3 1. .0 0. 2 0. 3 50. .0 1. 9 6, .3 3. .2 4. , 7 33, .5 0. ,5 1, .6 0. . 5 0, .7 30. .4 67, .5 91.5 41.5 66.5 100.0 66.5 50.0 50.0 25.0 25.0 8.5 cr. 41.5 50.0 50.0 March (8) Impor-Impor-tanoe — Volume — tance Value (ml) (%) Value (%) 19.0 26.9 24.6 37.1 4.0 5.7 2.4 3.6 2.8 4.0 2.7 4.1 2.5 3.5 3.5 5.3 20.7 29.4 19.6 29.5 4.7 6.7 3.4 5.1 4.5 6.4 3.2 4.8 3.6 5.1 1.3 2.0 1.8 2.6 2.2 3.3 1.3 1.8 0.7 1.1 1.6 2.3 0.8 1.2 4.0 5.7 2.0 3.0 70.5 66.4 00 ON Appendix Table S. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in foreeted and cutover areas, continued. Fre-quency (%) Gaultheria shallon Rubus spp. Vaooinium spp. Thuja plicata Alectoria sarmentosa Epilobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Pseudotsuga-• menziesii . Equisetum spp. Tsuga heterophylla Abies amabilis Ptevidium aqualinium Tiarella trifoliata Rosa spp. Linnaea borealis Laatuca muralis Hieracium albiflorum Potentilla palustris Total 70.0 90.0 80.0 100.0 70.0 30.0 70.0 40.0 20.0 10.0 80.0 80.0 10.0 April (6) May (7) June (6) — Volume (ml) 4.0 3.4 1.7 6.4 34.5 14.5 1.3 tr. 44.9 4.0 28.3 4.4 6.5 (%) Impor-tance Value Impor-tance Value (%) Fre-quency (%) — Volume — (ml) (%) Impor-tance Value Impor-tance Fre-Value quency (%) (%) 2. 6 1. 8 4. 4 10. 0 0.8 0.5 0.1 0.2 2. 2 2. 0 4. 8 90. 0 44.7 30.5 27.5 44.9 1. 1 0. 9 2. 2 90. 0 8.6 5.9 5.3 8.6 4. 2 4. 2 10.2 10. 0 - - - -7. 9 5. 5 13. .3 25. 0 - - — 9. .4 2. ,8 6. .8 65. 0 36.7 25.0 16.3 26.6 0. .8 0. ,6 1. .5 75. .0 10.4 7.1 5.3 8.6 45. ,0 4.0 2.7 1.2 2.0 29, .2 5. .8 14, .0 20. .0 • 10.3 7.0 1.4 2.3 2 .6 0 .3 0 .7 _ _ - - -18 .4 14 .7 35 .6 - - - - -2 .9 2 .3 5 .6 50 .0 2.8 1.9 1.0 1.6 4 .2 0 .4 1 .0 - - - - -25 .0 6.5 4.4 1.1 1.8 25 .0 5.0 3.4 0.9 1.5 10 .0 16.8 11.5 1.2 2.0 17.0 100.0 67.0 17.0 83.0 83.0 17.0 Impor-Impor- tance. — Volume — tance Value (ml) (%) Value (%) 22.5 9.7 1.6 2.8 31.9 13.8 13.8 24.1 10.0 4.3 2.9 5.1 tr. - - -69.6 30.0 24.9 43.5 21.6 9.3 7.7 13.5 153.9 41.3 146.6 61.3 33. ,0 0.8 0.3 0.1 0.2 33. .0 6.8 2.9 1.0 1.7 33. .0 1.8 0.8 0.3 0.5 17. .0 67.0 28.9 4.9 8.6 232.0 57.2 l-o 00 — I Appendix Table 8. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in forested and cutover areas, continued. Fre-quency (%) July (5) 2 — Volume — (ml) (%) Impor-tance Value Impor-tance Value (%) Fre-quency (%) August (11): — Volume — (ml) (%) Impor-tance Value Impor-tance Value (%) Fre-quency (%) September (2) 2--— Volume — (ml) (%) Impor-tance Value Impor-tance Value (%) Gaultheria shallon - - - - - - - — — 7 Rubus spp. 60.0 1.8 1.0 0.6 0.8 73.0 34.3 15.6- 11.4 21.0 50.0 8.0 6. 2 3. .1 3.4 Vaccinium spp. 20.0 0.5 0.3 0.1 0.1 9.0 15.3 7.0 0.6 1.1 50.0 4.0 3. ,1 1, .6 1.8 Thuja plioata 20.0 0.5 0.3 0.1 0.1 9.0 10.0 4.6 0.4 0.7 100.0 20.0 15. ,4 15, .4 16.9 Alectoria sarmentosa 20.0 10.0 5.4 1.1 1.5 18.0 1.3 0.6 0.1 0.2 100.0 4.0 3. ,1 3, .1 3.4 Epilobium 61 67.3 angustifolium 80.0 142.0 76.8 61.4 86.5 73.0 109.5 49.8 36.3 67.0 100.0 79.5 61. ,2 .2 Cornus canadensis 80.0 14.1 7.6 6.1 8.6 27 .0 2.3 i . o 0.3 0.6 100.0 2.3 1. .8 1 .8 2.0 Blechnum spicant _ _ - 9.0 tr. - - - 50.0 4.0 3. .1 1 .6 1.8 Grass spp. 60.0 tr. - - - - - - - - - — Fungi _ - - - 9.0 10.0 4.6 0.4 0.7 - -Gaultheria berries 20.0 5.0 2.7 0.5 0.7 Linnaea borealis 20.0 6.0 3.2 0.6 0.8 27.0 0.3 0.1 0.03 -Tsuga heterophylla 20.0 5.0 2.7 0.5 0.7 9.0 2.5 11.4 1.0 1.8 Lysitchum americanum 27.0 28.7 13.1 3.5 6.5 Cornus stolonifera 9.0 5.5 2.5 0.2 0.4 Araentlobium spp. 50.0 _8.0 6 .2 3 .1 3.4 Total 184.9 71.0 219.7 54.2 129.8 90 .9 ro oo oo Appendix Table 8. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in forested and cutover areas, continued. October2 (4) November (9) Impor- Impor- Impcr. Fre- Impor- tance Fre- Impor- tance Fre- Impor- tance quency — Volume — tance Value quency — Volume — tance Value quency — Volume — tance Value <Z) (ml) « ) Value (%) (%) (ml) (Z) Val ue ("/) (Z) (ml) <W Value <*> Gaultheria shallon 50.0 0.8 0.5 0.3 0.4 80.0 48.3 51.4 41.1 68.8 66.5 5.0 8.2 5.5 9.7 Rubus spp. - - -. - - 20.0 7.3 7.8 1.6 2.7 50.0 -- - — Vaccinium spp. 50.0 7.8 4.8 2.4 2.8 42.5 tr. - - - tr. - - — Thuja plicata 75.0 1.0 0.6 0.5 0.6 55.0 3.3 3.5 1.9 3.2 33.5 5.0 8.2 6.9 12.2 Alectoria sarmentosa 75.0 1.0 0.6 0.5 0.6 70.0 9.0 9.6 6.7 11.2 66.5 26.0 42.5 28.3 50.0 Epi lobium angustifolium 100.0 114.5 70.8 70.8 83.5 22.5 3.0 3.2 0.7 1.2 - - - - -Cornus canadensis 50.0 1.5 0.9 0.5 0.6 10.0 ' 4.5 4.8 0.5 0.8 16.5 1.5 2.5 0.4 0.7 Blechnum spicant 50.0 tr. - - 65.0 2.7 2.9 1.9 3.2 33.5 1.0 1.6 0.5 0.9 Grass spp. 25.0 2.0 1.2 0.3 0.4 - - - — — - - - - -Fungi 50.0 23.0 14.2 7.1 8.4 32.5 9.5 10.1 3.3 5.5 - - - - -Liverwort sporophyte 25.0 0.5 0.3 0.1 0.1 - - - - - 37 .5 tr. 27.8 — — Linnaea borealis 25.0 1.5 0.9 0.2 0.2 - - - - - 33.5 17.0 9.3 16.4 Tsuga heterophylla 25.0 3.0 1.9 0.5 0.6 25.0 2.7 2.9 0.7 1.2 66.5 3.0 4.9 3.3 5.8 Tellemia grandiflora 25.0 5.0 3.1 1.6 1.9 - - - - - - — ~ — — Lobaria oregana 25.0 0.8 0.9 0.2 0.3 66.5 2.0 3.3 2.2 3.9 Polystichum muni turn 35.0 2.9 3.1 1.1 1.8 - - - - -Rosa spp. - - - - - 16.5 0.7 1.1 0.2 0.4 Total. 161.6 84.8 94.0 59.7 61.2 56.6 'importance value Is 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. 2Samples were not taken from deer in forested areas In these months; data are for deer from cutover areas only. 3 Number of rumens analyzed. 11 tr. = trace - volume of forage type was at or below 0.5 ml. oo vo Appendix Table 9. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in forested areas. Fre-quency (%) 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 February (3)' March (2) April (1) Impor-— Volume — tance (ml) (%) Value Impor-tance Fre-Value quency (%) (») — Volume — (ml) (%) Impor-tance Value Impor-tance Fre-Value quency (%) (%) — Volume — (ml) (%) Impor-tance Value 100.0 16.3 47.8 47.8 53. 2 100.0 13.0 17.8 17.8 19. .5 100.0 0.5 0.6 0. 6 _ _ 50.0 0.5 0.7 0.4 0. .4 100.0 4.0 5.1 5. 1 67.0 0.5 1.5 1.0 1. 1 50.0 2.0 2.7 1.4 1 .5 100.0 0.5 0.6 0. 6 67.0 7.5 22.0 14.7 16. .3 100.0 2.3 3.1 3.1 3 .4 100.0 4.0 5.1 5. .1 100.0 4.3 12.6 12.6 14. 0 100.0 41.5 56.8 56.8 62 .1 100.0 65.0 82.3 82. 3 67.0 0.3 0.9 0.6 0. .7 50.0 2.0 2.7 1.4 1 .5 100.0 0.5 0.6 0. ,6 - - - - 50.0 tr. - - - - -33.0 0.5 1.5 0.5 0 .6 50.0 0.5 0.7 0.4 0 .4 100.0 3.7 10.8 10.8 12 .0 100.0 3.3 4.5 4.5 4 .9 67.0 1.0 2.9 1.9 2. .1 50.0 7.5 10.3 5.2 5 .7 100.0 4.0 5.1 5 .1 50.0 0.5 0.7 0.4 0 .4 100.0 0.5 0.6 0, .6 34.1 89.9 73.1 91.4 79.0 100 .0 Impor tanoe Value (%) 0.6 5.1 0.6 5.1 82.3 0.6 5.1 0.6 to vO o Appendix Table 9. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in forested areas, continued. May (2) November (4) December (1) Fre-quency Volume — Impor-tance Value Impor-tance Value Fre-quency Volume — (ml) (%) Impor-Impor- tance Fre-tance Value quency Value (%) (%) Impor-— Volume — tance (ml) (7.) Value Impor tance Value (%) Gaultheria shallon 100.0 40.5 40.3 40.3 56.4 100. .0 3. .0 4. .7 4. .7 4. .7 Rubus spp. 100.0 80.0 50.3 50. ,3 61. .4 - - - - -Vaccinium spp. 100.0 12.0 7.5 7. 5 9. 2 25.0 tr. - - - .8 Thuja plioata _ _ - 50.0 5.0 5.0 2.5 3.5 100. 0 5. ,0 7. ,8 7. 7. 8 Alectoria sarmentosa 50.0 tr. - 100.0 15.0 14.9 14.9 20.8 100. 0 52. ,0 81. .3 81. .3 81. .3 Epi lobium angus tifo Hum 50.0 8.0 5.0 2. .5 3. ,0 25.0 6.0 6.0 1.5 2.1 Cornus canadensis 50.0 3.5 2.2 1. ,1 1. .3 - - - - -Blechnum spicant 50.0 8.0 5.0 2. ,5 3. .0 50.0 2.5 2.5 1.3 1.8 Grass spp. - - - - - - - -Fungi - - - 25.0 19.0 18.9 4.7 6.6 Liverwort sporophyte 100.0 4.0 2.5 2. .5 3. .0 Tsuga heterophylla 100.0 5.5 3.5 3. .5 4. .3 50.0 5.3 5.3 2.7 3.8 100. .0 2, .0 3, .1 3 .1 3, .1 Pteridium aqualinum 50.0 13.0 8.2 4, .1 5, .0 Tiarella trifoliata 50.0 10.0 6.3 3, ,2 3, .9 Maianthemum dilatation 50.0 7.0 4.4 2, .2 2 .7 Lysitchum amerioanum 50.0 8.0 5.0 2. .5 3, .0 Lobaria oregana 50.0 1.5 1.5 0.7 1.0 100 .0 2 .0 3 .1 3 .1 3. .1 Polystichum muni turn 50.0 4.3 4.3 2.2 3.1 Abies amabilis 25.0 1.5 1.5 0.7 1.0 Total 159.0 81 .9 100.6 71.5 64 .0 100 .0 'importance value is 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. 2Number of rumens analyzed. 3 t r . = trace - volume of forage type was at or below 0.5 ml Appendix Table 10. Monthly frequency, volumes and importance values of forage species occurring in greatest volumes in rumens of black-tailed deer in cutover areas. Gaultheria nliallon Rubus spp. Vaooinium spp. Thuja plicata Alectoria sarmentosa Epilobium angus tifo Hum Cornus canadensis Blechnum spicant Grass spp. Fungi Linnaea borealis Dryopteris austriaca Abies amabilis Berberis nervosa Pseudotsuga menziesii Equisetum spp. Tsuga heterophylla Polystichum muni turn Total January (3)' February (2) March (6) Fre-quency (%) — Volume (ml) (%) Impor-tance Value Impor-tance Value (%) Fre-quency (%) — Volume (ml) (%) Impor-tance Value Impor-tance Value (%) Fre-quency (%) — Volume (ml) (%) Impor-tance Value Impor-tance Value (%) 67.0 3.0 8. 3 5.6 9.4 50.0 15.0 57.7 28.9 50.0 83.0 25.1 33. 1 27.5 41.8 _ _ _ _ - - 33.0 7.5 9. 9 3.3 5.0 100.0 1.3 3.6 3.6 6.0 100.0 tr. - - - 83.0 3.7 4. 9 4.1 6.2 33.0 tr. _ - 100.0 tr. - - - 100.0 2.8 3. 7 3.7 5.6 33.0 t r . 3 - - - - — 33.0 tr. 33.0 20.0 58.1 18.2 30.4 50.0 6.0 23.1 11.6 20.1 50.0 7.3 9. 6 4.8 7.3 100.0 5.5 15.2 15.2 25.4 100.0 4.0 15.4 15.4 26.6 100.0 8.9 11. 7 11.7 17.8 33.0 tr. - - - - - - — — — 67.0 0.5 1.4- 0.9 1.5 50.0 7.2 9. 5 4.8 7.3 : 33.0 1.0 2.7 8.9 14.9 0.8 67.0 3.0 8.3 5.6 9.4 50.0 1.0 3.8 1.9 3.3 17.0 3.5 4. .6 1.2 33.0 2.0 5.5 1.8 3.0 33.0 5.0 6. .6 2.2 3.3 33.0 2.0 2. ,6 0.9 1.4 50.0 2.3 3. .0 1.5 2.3 67.0 0.6 0. .8 0.5 0.8 36.3 59.8 26.0 57.8 75.9 65.8 Appendix Table 10. Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in cutover areas, continued. Fre-quency (%) 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 40.0 80.0 60.0 100.0 40.0 60.0 40.0 80.0 40.0 April (5) — Volume — (ml) (%) 7.5 2.9 2.8 8.8 4.0 29.0 2 Jo tr. 89.8 3.2 1.2 1.2 3.8 1.7 12.4 0.9 38.4 Impor-tance Value Impor-tance Value (%) Fre-quency (%) 7.4 0.4 15.4 2.7 2.0 1.4 7.7 1.4 15.1 0.8 31.4 20.0 8.0 3.4 0.7 1. ,4 60.0 56.2 24.0 14.4 29. ,4 40.0 2.0 0.9 0.4 0. .8 60.0 4.7 2.0 1.2 2. .4 20.0 13.0 5.6 1.1 2, .2 40.0 3.0 1.3 0.5 1, .0 20.0 80.0 80.0 20.0 80.0 100.0 40.0 40.0 20.0 20.0 20.0 May (5) June (6) 233.8 49.0 7.0 4.0 33.5 163.6 4.3 2.4 20.5 — Volume (ml) (%) Impor-tance Value Impor-tance Value (%) Fre-quency (%) — Volume (ml) (%) Impor-tance Value Impor-tance Value (%) 1.5 0.9 0.2 0.3 17.0 22.5 9.7 1.6 2.8 9.4 5.7 4.6 7.1 100.0 31.9 13.7 13.7 24.0 5.1 3.1 2.5 3.9 67.0 10.0 4.3 2.9 5.l' tr. - - - - - — — - - - - 17.0 tr. ~ 65.3 39.9 31.9 49.4 83.0 69.6 30.0 24.9 43.6 17.3 10.6 10.6 16.4 83.0 21.6 9.3 7.7 13.5 tr. - - - - - — -20.5 12.5 5.0 7.7 17.0 tr. - — — 0.9 4.8 4.1 64.6 1.4 7.4 6.3 33. .0 6. 8 2. ,9 1.0 1.7 33, .0 0. .8 0. .3 0.1 0.2 33, .0 1. ,8 0. .8 0.3 0.5 17 .0 67. .0 28. .9 4.9 8.6 232, .0 57.1 t\3 VO Appendix Table 10. Monthly frequency, volumes and importance values 1 of forage species occurring in gr volumes in rumens of black-tailed deer in cutover areas, continued. Fre-quency (%) 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 July (5) August (11) — Volume — (ml) (%) 279.2 Impor-tance Value Impor-tance Value (%) Fre-quency (%) —Volume — (ml) (%) Impor-tance Value 57.1 203.9 63.0 Impor-tance Ere-Value quency (%) (%) 60.0 1.8 0.6 3.6 6.3 73.0 34.3 16.8 12.3 19.5 50. 0 20.0 0.5 0.2 _ - 91.0 15.3 7.5 6.8 10.8 50. 0 20.0 0.5 0.2 - - 9.0 10.0 4.9 0.4 0.6 50. 0 20.0 10.0 3.6 0.7 1.2 18.0 1.3 0.6 0.1 0.2 100. 0 80.0 142.3 51.0 40.8 71.4 73.0 109.5 53.7 39.2 62.2 100. .0 80.0 14.1 . 5.1 4.1 7.2 27.0 2.3 1.1 0.3 0.5 100. .0 - - - 9.0 tr. - - - 50. .0 60.0 tr. - - - - — : 20.0 5.0 1.8 0.4 0.7 20.0 6.0 2.1 0.4 0.7 20.0 94.0 33.7 6.7 11.7 0.2 20.0 5.0 1.8 0.4 0.7 9.0 2.5 1.2 0.1 27.0 28.7 14.1 3.8 6.0 50 .0 September (2) — Volume — (ml) (%) 8.0 4.0 40.0 4.0 5 3 4.0 79 2 8.0 149.8 5.3 2.7 26.7 2.7 53.1 1.5 2.7 5.3 Impor-tance Value 2. 1. 13. 2. 53.1 1.5 1.4 2.7 78.8 Impor-tance Value (%) 3. 1. 16. 3. 67.4 1.9 1.8 3.4 4> Appendix Table 10 . Monthly frequency, volumes and importance values 1 of forage species occurring in greatest volumes in rumens of black-tailed deer in cutover areas, continued. October (4) November (5) December (3) Fre-Volume Impor-tance Impor-tance Value Fre-quency — Volume Impor-tance Impor-tance Value Fre-quency Volume — Gaultheria shallon Rubus spp. Vaccinium spp. Thuja plicata Alectoria sarmentosa Epilobium angustifolium Cornus canadensis Blechnum spicant Grass spp. Fungi Linnaea borealis Tsuga heterophylla Tellemia grandiflora Polystichum muni turn Lactuca muralis Rosa spp. Lobaria oregana Abies amabilis Total Impor-tance Impor-tance Value 1 J (%) (ml) (%) Value (%) (%) (ml) (%) Value (%) (%) (ml) (%) Value (%) 50.0 0.8 0.5 0.3 0.4 60.0 56.0 61.5 36.9 71.8 33.0 7.0 10.9 3.6 6.2 _ _ _ _ - 40.0 14.5 15.9 6.4 12.5 - - - - -50.0 7.8 4.8 2.4 2.8 60.0 0.5 0.5 0.3 0.6 100.0 0.7 1.1 1.1 1.9 75.0 1.0 0.6 0.5 0.6 60.0 1.7 1.9 1.1 2.1 67.0 9.5 14.8 9.9 17.1 75.0 1.0 0.6 0.5 0.6 40.0 3.0 3.3 1.3 2.5 33.0 tr. — — — 100.0 114.5 71.1 71.1 84.3 _ _ - - - - - - - -50.0 1.5 0.9 0.5 0.6 20.0 9.0 9.9 2.0 3.8 33.0 3.0 4.7 1.6 2.8 50.0 tr. - - - 80.0 2.8 3.1 2.5 4.9 67.0 2.0 3.1 2.1 3.6 25.0 2.0 1.2 0.3 0.4 - - - - - - - - — — 50.0 23.0 14.-3T 7.2 8.5 40.0 tr. - - - - - - - -25.0 1.5 0.9 0.2 0.2 67.0 34.0 53.0 35.5 61.3 25.0 3.0 1.9 0.5 0.6 33.0 4.0 6.2 2.0 3.5 25.0 5.0 3.1 0.8 0.9 20.0 1.5 1.6 0.3 0.6 20.0 1.5 1.6 0.3 0.6 60.0 0.5 0.5 0.3 0.6 33.0 1.5 2.3 0.8 1.4 33.0 2.0 3.1 1.0 1.7 33.0 0.5 0.8 0.3 0.5 161.1 84.3 91.0 51 .4 64 .2 57.9 'importance value is the product of percent frequency ol' 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. 2Number of rumens analyzed. 3 t r . = trace - volume of forage type was at or below 0.5 ml. 

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