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Initial effects of clearcutting on the flow of chemicals through a forest-watershed ecosystem in south-western… Feller, M. C. (Michael Charles) 1975

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INITIAL EFFECTS OF CLEARCUTTING ON THE FLOW OF CHEMICALS THROUGH A FOREST-WATERSHED ECOSYSTEM IN SOUTHWESTERN BRITISH COLUMBIA by  MICHAEL CHARLES FELLER B. Sc. Hons., University of Melbourne ( A u s t r a l i a ) , 1968 M. Sc.(Chem.) University of Melbourne ( A u s t r a l i a ) , 1969  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE  REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY (Forest Ecology) i n the Faculty of Forestry  accept t h i s thesis as conforming to the required  THE UNIVERSITY OF BRITISH COLUMBIA  Spring,^ 1975  standard  In presenting  t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements f o r  an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y a v a i l a b l e for reference  and study.  I further  agree that permission f o r extensive copying of t h i s thesis f o r s c h o l a r l y purposes may  be granted by the Head of my Department or by h i s  representatives.  I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission.  Faculty of Forestry The University of B r i t i s h Columbia, Vancouver, B.C.  V6T  Canada.  Date  £  / II J7<j  1W5,  i  ABSTRACT  A l i t e r a t u r e survey indicated that l i t t l e was known about the e f f e c t s of commercial  c l e a r c u t t i n g on stream and watershed  solution chemistry.  To  investigate these e f f e c t s , f i v e small watersheds were studied i n the University of B.C. Research Forest.  Three of the watersheds were equiped with weirs,  stream height recorders, and soil-air-water thermographs. i n the three c a l i b r a t e d watersheds and equiped and hanging water column tension lysimeters.  S o i l p i t s were dug  with surface runoff c o l l e c t o r s Samples of - p r e c i p i t a t i o n above  the f o r e s t , throughfall (through forest and slash), surface runoff, forest f l o o r leachate, mineral s o i l leachate near the bottom of the rooting zone, groundwater, and streamwater - were c o l l e c t e d at regular i n t e r v a l s and analyzed for pH, e l e c t r i c a l conductivity, a l k a l i n i t y as bicarbonate, K, Na, Mg, Ca, Fe, Mn, A l , C l , P, N, S, and S i f o r periods of up to three years p r i o r to c l e a r cutting and two years a f t e r c l e a r c u t t i n g . dissolved oxygen and suspended sediment.  Streamwater was also analyzed f o r Sampling was carried out f o r periods  of up to three years p r i o r to c l e a r c u t t i n g and up to two years following c l e a r cutting . The streams were characterized by high discharges from late autumn u n t i l early summer and low discharges from May u n t i l October, with almost no c o n t r i bution from snowmelt runoff.  Response to p r e c i p i t a t i o n was f a i r l y rapid and  i t was hypothesized that stormflow arose mainly from flow of water through macrochannels i n the s o i l .  V i s u a l observations and chemical data were con-  s i s t e n t with t h i s hypothesis. Evapotranspiration from the gauged watersheds was estimated to be about 85 cm per year by subtracting streamflow outputs from p r e c i p i t a t i o n inputs  ii  and  65 cm p e r y e a r u s i n g t h e o r e t i c a l methods.  two  v a l u e s was  The  a t t r i b u t e d t o an unmeasured leakage  from the u n t r e a t e d c o n t r o l watershed which rendered puts. 27.6  There was cm  an i n c r e a s e o f 30.8  from another  mediately  t r o l watershed was  141.5  Stream temperatures 0°C and  these  o f water, p a r t i c u l a r l y too low the streamflow  cm i n r u n o f f from one watershed,  d u r i n g the f i r s t  following clearcutting.  d i s c r e p a n c y between  out-  and  s i x months o f the dormant season  im-  D u r i n g t h i s p e r i o d r u n o f f from the con-  cm. underwent annual  summer maxima c l o s e t o 17°C.  c y c l e s w i t h w i n t e r minima c l o s e t o  D i u r n a l temperature f l u c t u a t i o n s were  s l i g h t and u s u a l l y l e s s than a few d e g r e e s . i n b o t h maximum and minimum stream  C l e a r c u t t i n g caused  temperatures  an i n c r e a s e  d u r i n g the f i r s t dormant s e a -  son f o l l o w i n g c l e a r c u t t i n g . The  few measurements which were made o f suspended sediment, t o g e t h e r  with  v i s u a l o b s e r v a t i o n s , i n d i c a t e d t h a t c o n c e n t r a t i o n s were u s u a l l y n e g l i g i b l e in  the  streams.  D i s s o l v e d oxygen c o n c e n t r a t i o n s i n streams were u s u a l l y c l o s e t o 100% t u r a t i o n and underwent annual  sa-  c y c l e s w i t h maximum v a l u e s i n w i n t e r and minimum  v a l u e s i n l a t e summer and e a r l y autumn.  C l e a r c u t t i n g had  l i t t l e e f f e c t on  dis-  s o l v e d oxygen v a l u e s d u r i n g the c o o l e r w e t t e r months b u t caused v e r y pronounced decreases cal  d u r i n g summer and  e a r l y autumn.  and c h e m i c a l oxygen demands o f d e c a y i n g  T h i s was  a t t r i b u t e d t o the  s l a s h i n the  biologi-  streams.  Stream c h e m i s t r y e x h i b i t e d l i t t l e d i u r n a l v a r i a t i o n b u t c o n s i d e r a b l e v a r i a t i o n with discharge. bicarbonate  Sodium, c a l c i u m , magnesium, d i s s o l v e d s i l i c a ,  c o n c e n t r a t i o n s , and  e l e c t r i c a l c o n d u c t i v i t y and pH decreased  i n c r e a s i n g d i s c h a r g e , whereas p o t a s s i u m some i n c r e a s e s and  some d e c r e a s e s .  and with  and n i t r a t e c o n c e n t r a t i o n s e x h i b i t e d  C h l o r i d e and  g e n e r a l l y not s i g n i f i c a n t l y r e l a t e d t o d i s c h a r g e .  s u l p h a t e c o n c e n t r a t i o n s were  iii  In t h e u n d i s t u r b e d  ecosystems, c h e m i c a l c o n c e n t r a t i o n s , pH, and e l e c t r i -  c a l c o n d u c t i v i t y throughout  the systems were g e n e r a l l y h i g h e s t i n l a t e summer  and e a r l y autumn and lowest  i n w i n t e r and e a r l y s p r i n g .  T h i s was  t o s e a s o n a l c y c l e s o f g e o l o g i c a l and b i o l o g i c a l a c t i v i t y w i t h of weathering  and d e c o m p o s i t i o n  These were f l u s h e d through  accumulation  p r o d u c t s o c c u r r i n g d u r i n g d r y , warm summers.  the system i n autumn, w i t h s o l u t i o n s becoming p r o -  g r e s s i v e l y more d i l u t e throughout ther.  attributed  the w i n t e r u n t i l t h e o n s e t o f warmer wea-  N i t r a t e c o n c e n t r a t i o n s tended  t o be h i g h e r i n w i n t e r than i n summer which  was a t t r i b u t e d t o g r e a t e r n i t r o g e n uptake by organisms i n summer. The most abundant i o n s i n p r e c i p i t a t i o n and t h r o u g h f a l l were hydrogen, s u l p h a t e , and c h l o r i d e , w h i l e c a l c i u m , b i c a r b o n a t e , and s u l p h a t e were dominant i n a l l the o t h e r types o f water samples. i n chemical  c o n c e n t r a t i o n s t o maximum v a l u e s i n f o r e s t f l o o r l e a c h a t e  lowed by a d e c r e a s e  f o l l o w e d by a steady  fol-  t o minimum v a l u e s i n groundwater, and a s l i g h t i n c r e a s e  a g a i n i n streamwater.  water  There was a g e n e r a l i n c r e a s e  The lowest pH v a l u e s were i n t h r o u g h f a l l (4.0-4.5) i n c r e a s e through  the system t o maximum v a l u e s i n stream-  (6.5-7.0). C l e a r c u t t i n g i n c r e a s e d the pH o f water r e a c h i n g t h e f o r e s t f l o o r and  surface r u n o f f but decreased and streamwater.  the pH o f m i n e r a l s o i l  I t g e n e r a l l y decreased  l e a c h a t e , groundwater,  c h e m i c a l c o n c e n t r a t i o n s i n water  r e a c h i n g t h e f o r e s t f l o o r and i n s u r f a c e r u n o f f , and, t o a l e s s e r i n f o r e s t f l o o r and m i n e r a l s o i l  leachates, but i t increased concentrations  i n groundwater and, t o a l e s s e r e x t e n t , i n streamwater. c r e a s e throughout  groundwater.  A most n o t a b l e i n -  t h e system was i n the c o n c e n t r a t i o n o f potassium  a t t r i b u t e d t o t h e r e l a t i v e ease w i t h which potassium vegetation.  extent,  which was  i s l e a c h e d from  decaying  I n c r e a s e s i n n i t r a t e c o n c e n t r a t i o n s were p a r t i c u l a r l y h i g h i n  iv  Streamwater concentrations of potassium,  i r o n , calcium, dissolved oxy-  gen, and probably manganese, were s i g n i f i c a n t l y affected by clearcutting; concentrations of a l l these chemicals increased, except dissolved oxygen which decreased.  S l i g h t increases i n magnesium, n i t r a t e , sulphate, and  chloride concentrations, and e l e c t r i c a l conductivity, and decreases i n pH and bicarbonate concentrations were also observed.  A l l changes were most  noticeable during the low flow periods of late summer and early autumn. There were no obvious e f f e c t s on sodium, aluminium, ammonium, dissolved s i l i c a , and phosphate concentrations. In terms of chemical budgets, there was a general net loss of calcium, sodium, magnesium, potassium, and sulphur from a l l the watersheds, i n t h e i r undisturbed state, while nitrogen was accumulated and phosphorus underwent very l i t t l e change.  The c h l o r i d e balance changed from year to year with  losses one year and gains the next.  Chemical outputs increased r e l a t i v e to  inputs with increasing p r e c i p i t a t i o n so that net losses were greater i n wint e r than i n summer. Chemical budgets and stream chemistry at Haney were compared to the r e s u l t s o f other studies, p a r t i c u l a r l y one i n the nearby Seymour watershed (Zeman, 1973). At Haney, c l e a r c u t t i n g s i g n i f i c a n t l y increased potassium losses and decreased nitrogen gains i n one watershed and s i g n i f i c a n t l y increased potassium, sodium, magnesium, and c h l o r i d e losses i n another watershed. From the nutrient viewpoint, i t appears that c l e a r c u t t i n g has not impaired the mechanisms f o r n u t r i e n t retention i n the ecosystems of the type present i n the study area.  This may not be the case f o r a l l ecosystems i n  coastal B.C., or f o r other f o r e s t r y p r a c t i c e s , such as slashburning.  V  The  study has p o i n t e d  o u t t h e need f o r f u r t h e r work t o q u a n t i f y the  r o l e o f macrochannels i n s o i l s w i t h r e s p e c t  to hydrologic  haviour  o u t t h e danger o f e x t r a p o l a t i n g  o f watersheds.  I t has a l s o p o i n t e d  t o l a r g e r ecosystems the r e s u l t s o f l y s i m e t e r s t u d i e s . o f groundwater may o f f e r a more a c c u r a t e from s o i l s  t h a n do l y s i m e t e r s .  and c h e m i c a l be-  Chemical a n a l y s i s  means o f e s t i m a t i n g  chemical  losses  vi  TABLE OF CONTENTS Page ABSTRACT  TABLE OF CONTENTS  vi  LIST OF TABLES  vm  LIST OF FIGURES  xi  ACKNOWLEDGEMENTS  Xll  CHAPTER 1  CHAPTER 2  INTRODUCTION E c o l o g i c a l e f f e c t s of c l e a r c u t t i n g  2  E f f e c t s on the s o i l  3  E f f e c t s on l i v i n g  12  E f f e c t s on streams and aquatic ecosystems  25  Objectives of the thesis  40  DESCRIPTION OF THE STUDY AREA  41  Location  41  Climate  41  Geology, landforms, and s o i l s  46  Vegetation  48  Watershed CHAPTER 3  CHAPTER 4  organisms  description  55  EXPERIMENTAL METHODS  58  F i e l d instrumentation and sampling techniques  58  Chemical analyses  66  STREAM BEHAVIOUR  71  Stream hydrology  71  Stream and s o i l temperature  83  Suspended sediment  88  Dissolved oxygen pH E l e c t r i c a l conductivity Ions and dissolved s i l i c a Chemical budgets General discussion Summary CHAPTER 5  SOLUTION CHEMISTRY OF THE ENTIRE FOREST-WATERSHED ECOSYSTEM pH E l e c t r i c a l conductivity Cations Anions and dissolved s i l i c a General discussion Summary  CHAPTER 6  CONCLUSIONS  LITERATURE CITED APPENDICES I  Stage-discharge c a l i b r a t i o n of weirs A, B, and C  II  Descriptions of s o i l  III  S o i l p r o f i l e physical and chemical properties  IV  Mathematical B, and C  V  Annual average chemical composition of streams A, B, and C  VI  Examples of potentiometric bicarbonate concentrations  VII  Lysimeter tensions and volumes of solution c o l l e c t e d  profiles  r e l a t i o n s h i p s between discharges at weirs A,  VIII Contents of slash throughfall c o l l e c t o r s IX  Tree volumes and slash loadings i n the study area  X  S t a t i s t i c a l comparison of chemical concentrations i n streams, and chemical losses from watersheds, before and after clearcutting  XI  Monthly average chemical concentrations i n throughfall after clearcutting  XII  Chemical analyses of" groundwater at Haney  XIII Monthly chemical .budgets f o r the d i f f e r e n t watersheds XIV  Relationships between monthly chemical loads and amount of p r e c i p i t a t i o n and discharge  XV  S c i e n t i f i c names of the major plant species present i n the watersheds at Haney  Vlll  LIST OF TABLES Table  Page  2.1  Annual average p r e c i p i t a t i o n f o r the three guaged watersheds at Haney  41  2.2  P r e c i p i t a t i o n at Haney during the study period  44  2.3  C l i m a t o l o g i c a l data f o r two weather stations at Haney  45  2.4  R e l a t i v e d i s t r i b u t i o n of the major tree species i n watersheds A, B, and C  48  2.5  P h y s i c a l c h a r a c t e r i s t i c s of the watersheds at Haney  55  2.6  Relative watershed areas and stream discharges  56  3.1  Detection l i m i t s of chemicals by the a n a l y t i c a l methods used.  66  3.2  P r e c i s i o n of the chemical analyses  66  4.1  P r e c i p i t a t i o n and runoff f o r the watersheds at Haney  78  4.2  Estimates of evapotranspiration f o r Haney  79  4.3  Measured and predicted values of stream discharge following c l e a r c u t t i n g  83  4.4  Suspended sediment concentrations i n streams leaving the watershed .  88  4.5  Average pH values of streams before and a f t e r c l e a r cutting  115  4.6  E l e c t r i c a l c o n d u c t i v i t i e s o f stations B and C and four tributaries  122  4.7  E l e c t r i c a l conductivity of subsurface seepage water i n Polystichum - Thuja p l i c a t a ecosystems of d i f f e r e n t ages i n the U.B.C. Research Forest  123  4.8  Ionic sums from streamwater analyses  126  4.9  Average e l e c t r i c a l c o n d u c t i v i t i e s of streams before and a f t e r c l e a r c u t t i n g  128  4.10  Seasonal v a r i a t i o n of cation concentrations i n streamwater i n temperate regions  132  4.11  V a r i a t i o n of cation concentrations i n streams i n temperate regions with increasing stream discharge  134  4.12  Average concentrations of cations i n streamwater before and a f t e r c l e a r c u t t i n g  135  4.13  Seasonal v a r i a t i o n of dissolved s i l i c a and anion concentrations i n streamwater i n temperate regions  155  4.14  V a r i a t i o n of dissolved s i l i c a and anion concentrations i n streamwater i n temperate regions with increasing ' stream discharge  157  IX  Table  Page  4.15  Average c o n c e n t r a t i o n s o f d i s s o l v e d s i l i c a and a n i o n s i n streams b e f o r e and a f t e r c l e a r c u t t i n g  159  4.16  A n n u a l c h e m i c a l budgets  179  4.17  E s t i m a t e d maximum e r r o r s i n c h e m i c a l budget c a l c u l a t i o n s  181  4.18  A n n u a l c h e m i c a l budgets o f u n d i s t u r b e d ecosystems i n humid temperate r e g i o n s  185  4.19  Streamwater c h e m i s t r y d u r i n g a 24-hour p e r i o d , 5-6 November, 1973  189  4.20  Streamwater June, 1972  191  4.21  C a t i o n c o n c e n t r a t i o n s i n s i m i l a r streams i n t h e C h i l l i w a c k V a l l e y a r e a , November, 1972  193  4.22  Maximum measured c o n c e n t r a t i o n s o f s e l e c t e d c h e m i c a l s i n streamwater and p e r m i s s i b l e l i m i t s f o r human c o n sumption and o t h e r uses  197  5.1  Means and s t a n d a r d d e v i a t i o n s o f c h e m i c a l parameters obt a i n e d from a n a l y s i s o f a s i n g l e c o l l e c t i o n o f samples c o l l e c t e d on two d a t e s , one b e f o r e and one a f t e r c l e a r cutting  204  5.2  Means and s t a n d a r d d e v i a t i o n s o f c h e m i c a l parameters o b t a i n e d from a n a l y s i s o f one c o l l e c t i o n o f samples from t h e same b i o g e o c o e n o s i s  205  5.3  Average pH v a l u e s o f waters i n an u n d i s t u r b e d f o r e s t ecosystem a t Haney - watershed B  207  5.4  Average pH v a l u e s o f ecosystem waters b e f o r e and a f t e r c l e a r c u t t i n g - watershed B  210  5.5  Average e l e c t r i c a l c o n d u c t i v i t i e s o f waters i n an und i s t u r b e d f o r e s t ecosystem a t Haney - watershed B  211  5.6  Average e l e c t r i c a l c o n d u c t i v i t i e s o f ecosystem waters b e f o r e and a f t e r c l e a r c u t t i n g - watershed B  214  5.7  Average c a t i o n c o n c e n t r a t i o n s o f waters i n an u n d i s t u r b e d f o r e s t ecosystem a t Haney - watershed B  216  5.8  R a t i o s o f c a t i o n c o n c e n t r a t i o n s i n water a t d i f f e r e n t l e v e l s i n a f o r e s t ecosystem i n Germany  217  5.9  R e l a t i v e abundance o f t h e major c a t i o n s i n s o l u t i o n a t d i f f e r e n t l e v e l s i n the ecosystem  221  f o r e s t - watershed  c h e m i s t r y d u r i n g a 24-hour p e r i o d , 24-25  Table  Page  5.10  Average c a t i o n c o n c e n t r a t i o n s i n ecosystem waters b e f o r e and a f t e r c l e a r c u t t i n g - watershed B  232  5.11  Average a n i o n and d i s s o l v e d s i l i c a c o n c e n t r a t i o n s o f waters i n an u n d i s t u r b e d f o r e s t ecosystem a t Haney watershed B  235  5.12  R e l a t i v e abundance o f t h e major a n i o n s i n s o l u t i o n d i f f e r e n t l e v e l s i n t h e ecosystem  236  5.13  R a t i o s o f anion-element c o n c e n t r a t i o n s i n water a t d i f f e r e n t l e v e l s i n a f o r e s t ecosystem i n Germany  239  5.14  Average a n i o n and d i s s o l v e d s i l i c a c o n c e n t r a t i o n s i n ecosystem waters b e f o r e and a f t e r c l e a r c u t t i n g watershed B  249  5.15  Average c h e m i c a l c o m p o s i t i o n streamwater a t Haney  254  o f groundwater  and  at  xi  LIST OF FIGURES Figure  Page  2.1  Location of the study area  42  2.2  Isohyetal map of the watersheds  43  2.3  Forest cover  50  2.4  Biogeocoenoses of the watersheds  53  2.5  Location of clearcuts and major roads  57  3.1  The research area at Haney  60  3.2  A surface runoff c o l l e c t o r  63  3.3  A tension lysimeter, type 1  63  3.4  A tension lysimeter, type 2  63  4.1  Mean d a i l y discharges at the weirs at Haney  72  4.2  Response,of stream discharge to p r e c i p i t a t i o n during an October storm  73  4.3  Response of stream discharge to p r e c i p i t a t i o n during a January storm  74  4.4  Macrochannels exposed i n the faces of s o i l p i t s  77  4.5  Weekly maximum and minimum stream temperatures  80  4.6  Streamwater temperatures during a t y p i c a l summer's day and a t y p i c a l winter's day  81  4.7  Streamwater temperature during the passage of an a r c t i c front  82  4.8  . Relationships between maximum streamwater temperatures i n streams A and B and those of stream C  84  4.9  Relationships between minimum streamwater temperatures i n streams A and B and those of stream C  85  4.10  Weekly maximum and minimum s o i l temperatures  86  4.11  Yarding techniques f o r the watersheds at Haney  91  4.12  Stream channels before and a f t e r c l e a r c u t t i n g  92  4.13  Dissolved oxygen concentrations - streams A, B, and C  96  4.14  Dissolved oxygen percent saturation - streams A, B, and C  96  4.15  Diurnal v a r i a t i o n i n streamwater dissolved oxygen and pH - l a t e autumn  98  4.16  Diurnal v a r i a t i o n i n streamwater dissolved oxygen and pH - early summer  101  Xll  Figure  Page  4.17  Relationships between streamwater dissolved oxygen concentrations and discharge  104  4.18  Relationships between streamwater dissolved oxygen percent saturations and discharge  105  4.19  Streamwater dissolved oxygen during a storm event  106  4.20  Dissolved oxygen concentrations - streams D and E  109  4.21  Dissolved oxygen percent saturation - streams D and E  109  4.22  Streamwater pH - streams A, B, and C  112  4.23  Relationships between streamwater pH and discharge  113  4.24  Streamwater pH during a storm event  114  4.25  Streamwater pH - streams D and E  115  4.26  Streamwater e l e c t r i c a l conductivity - streams A, B, and C  118  4.27  Relationships between streamwater e l e c t r i c a l conductivi t y and discharge  119  4.28  Streamwater e l e c t r i c a l conductivity during a storm event  120  4.29  Relationships between e l e c t r i c a l conductivity and the sum of potassium, sodium, magnesium, and calcium concentrations  124  4.30  Relationships between e l e c t r i c a l conductivity and the sum of bicarbonate, sulphate, and chloride concentrations  125  4.31  Streamwater potassium concentrations - streams A, B, and C  129  4.32  Relationships between streamwater potassium concentrations and discharge  130  4.33  Streamwater cation concentrations during a storm event  131  4.34  Streamwater potassium concentrations - streams D and E  137  4.35  Streamwater sodium concentrations — streams A, B, and C  139  4.36  Relationships between streamwater sodium concentrations and discharge  140  4.37  Streamwater magnesium and calcium concentrations streams A, B, and C  142  4.38  Relationships between streamwater magnesium concentrat i o n s and discharge  144  4.39  Relationships between streamwater calcium concentrations and discharge  145  4.40  Streamwater calcium concentrations - streams D and E  146  Xlll  Figure  Page  4.41  Streamwater D and E  i r o n and manganese c o n c e n t r a t i o n s - streams  2.49  4.42  Streamwater C  ammonium c o n c e n t r a t i o n s - streams A, B, and  151  4.43  Streamwater  n i t r a t e c o n c e n t r a t i o n s - streams A, B, and C  151  4.44  R e l a t i o n s h i p s between streamwater ammonium c o n c e n t r a t i o n s and d i s c h a r g e  153  4.45  R e l a t i o n s h i p s between streamwater n i t r a t e c o n c e n t r a t i o n s and d i s c h a r g e  154  4.46  Streamwater b i c a r b o n a t e c o n c e n t r a t i o n s - streams A, B, and C  163  4.47  Streamwater d i s s o l v e d s i l i c a d u r i n g a storm e v e n t  164  4.48  R e l a t i o n s h i p s between streamwater b i c a r b o n a t e c o n c e n t r a t i o n s and d i s c h a r g e  • 165  4.49  Streamwater b i c a r b o n a t e c o n c e n t r a t i o n s - streams D and E  167  4.50  Streamwater B, and C  c o n c e n t r a t i o n s - streams A,  169  4.51  R e l a t i o n s h i p s between streamwater d i s s o l v e d s i l i c a c o n c e n t r a t i o n s and d i s c h a r g e  170  4.52  Streamwater C  172  4.53  R e l a t i o n s h i p s between streamwater s u l p h a t e c o n c e n t r a t i o n s and d i s c h a r g e  173  4.54  Streamwater  175  4.55  R e l a t i o n s h i p s between streamwater c h l o r i d e c o n c e n t r a t i o n s and d i s c h a r g e  177  5.1  pH o f ecosystem s o l u t i o n s  208  5.2  E l e c t r i c a l c o n d u c t i v i t y o f ecosystem s o l u t i o n s  212  5.3  P o t a s s i u m c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  223  5.4  Sodium  224  5.5  Magnesium c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  225  5.6  C a l c i u m c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  226  5.7  I r o n c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  227  5.8  Manganese c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  228  5.9  Ammonium c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  229  5.10  C h l o r i d e c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  241  dissolved s i l i c a  and a n i o n c o n c e n t r a t i o n s  s u l p h a t e c o n c e n t r a t i o n s - streams A, B, and  c h l o r i d e c o n c e n t r a t i o n s - streams A, B, and  c o n c e n t r a t i o n s i n ecosystem s o l u t i o n s  Figure  Page  5.11  Phosphate concentrations i n ecosystem solutions  242  5.12  N i t r a t e concentrations i n ecosystem solutions  243  5.13  Sulphate concentrations i n ecosystem solutions  244  5.14  Bicarbonate concentrations i n ecosystem solutions  245  5.15  Dissolved s i l i c a concentrations i n ecosystem solutions  246  XV  ACKNOWLEDGEMENTS  I would l i k e to express my gratitude to the people from whom I have received considerable support during the course of t h i s thesis. I am deeply indebted to Dr. J.P. Kimmins who not only enabled me t o begin a career i n f o r e s t r y , but also provided much guidance, encouragement, and f i n a n c i a l support, without which the present study could never have been completed. I am a l s o indebted to the members of my research committee, Drs. T.M. B a l l a r d , B.C. Goodell, P.G. Haddock, J.H.G. Smith and R.P. W i l l i n g ton, for advice and assistance during d i f f e r e n t phases of t h i s p r o j e c t . Mr. J . Walters and the s t a f f of the U n i v e r s i t y of B r i t i s h Columbia Research Forest often went out of t h e i r way to l e t me use t h e i r t i e s , f o r which I am g r a t e f u l .  facili-  I a l s o wish to thank Drs. T.A. Black  (Department of S o i l Science), A. Kozak, V.J. Krajina (Department o f Botany), and L.M. Lavkulich (Department of S o i l Science) f o r t h e i r usef u l comments. I would p a r t i c u l a r l y l i k e t o thank my colleague, K. Klinka, f o r many hours of u s e f u l and stimulating discussion and f o r l e t t i n g me use some of h i s s o i l and vegetation data. I must also thank K.M. Tsze for assistance with f i e l d work and l a boratory analyses and H.D. S c h e l l for assistance with laboratory analyses. In addition, I am indebted to L. Keir, K. Hejjas, and D. Roff f o r carrying  out the computer programming, and t o Penny Lewis, T r i c i a Rankin, and  Jean Williamson f o r typing most of the thesis'.  xvi  I  am g r a t e f u l f o r t h e f i n a n c i a l support  s e a r c h C o u n c i l B u r s a r y , by  s u p p l i e d by a N a t i o n a l  the Resource S c i e n c e  o f B r i t i s h Columbia, and by a K i l l a m P r e d o c t o r a l  Re-  C e n t r e a t the U n i v e r s i t y Fellowship.  1  CHAPTER 1.  INTRODUCTION  In coastal B.C. the most common method of harvesting ber c o n s i s t s of c l e a r c u t t i n g .  forests f o r tim-  Areas up to several thousand acres i n extent  have been cut progressively, but most have now been lmited to a maximum of about 200 acres (80 hectares) (Cameron, 1972) . Both s i l v i c u l t u r a l and short-term economic constraints i n the coastal region favour the use of c l e a r c u t t i n g over any a l t e r n a t i v e harvesting method, and f o r e s t e r s have t r a d i t i o n a l l y accepted c l e a r c u t t i n g as the most appropr i a t e harvesting method.  The general p u b l i c , however, i s becoming increas-  i n g l y concerned about c l e a r c u t t i n g . With an increasing concern over the goals of society and the type of environment created by technology, and a greater awareness of the f o r e s t as a national inheritance, people are demanding high q u a l i t y management of their forests.  Clearcutting i s widely considered to make the land  ugly,  to degrade i t by lowering i t s p r o d u c t i v i t y , and to lower the value of some of the f o r e s t ' s products, such as water and recreation.  Many people con-  sider that, i n the long run, forests and trees may be more important t o man and h i s well being as a part of the human environment than as a source of raw materials. Some f o r e s t e r s , p a r t i c u l a r l y those i n the U.S. where public c r i t i c i s m of f o r e s t r y has a longer h i s t o r y than i n B.C., are advocating better and more aesthetic practices 1970;  (e.g. Duncan, 1971; Hopkins, 1970;  J e f f r e y et al.,  Ruckelshaus, 1971; Spurr and Arnold, 1971; Wilson, 1970).  Others  have responded to the c r i t i c i s m by using economic and s i l v i c u l t u r a l  2  arguments t o s u p p o r t t h e i r case f o r c l e a r c u t t i n g c u t t i n g degrades the k i n , 1972;  U.S.  a lack of  data.  land  (e.g.  Senate, 1971).  Clearcutting  Brooks, 1971; Both s i d e s  imposes changes on  and  by  denying that  D u f f i e l d and  may  be  either subtle  nificance. ify  Reliable  aspects of the  a f o r e s t ecosystem t h a t  clearcutting  controversy.  as f o l l o w s :  t o the  The  I t i s the  ecological  first  These changes  r e v i e w e d i n 1970,  watershed n u t r i e n t  the  Hubbard Brook experiments  (e.g.  o v e r a l l aim  of  this  topic.  s t e p was  The  to review  known.  n e x t s t e p was When the  e f f e c t s o f c l e a r c u t t i n g on  c y c l i n g were not  social sig-  the  e f f e c t s of c l e a r c u t t i n g i n order  some o f t h e s e e f f e c t s about which l i t t l e was  was  extend f a r  t o t h e s e changes would h e l p t o c l a r -  approach used was  suggested that  by  data p e r t a i n i n g  t o determine which e f f e c t s were worthy, o f s t u d y .  and  hampered  have v a r y i n g e c o l o g i c a l and  literature pertaining  first  Har-  o r d r a m a t i c and  t h e s i s t o p r o v i d e such d a t a f o r . c e r t a i n a s p e c t s o f t h e The  D a v i s , 1971;  i n t h i s debate are  beyond t h e mere sudden removal o f t h e dominant v e g e t a t i o n .  clear-  known, but  Bormann et  study  literature  earlier  L i k e n s et al.,  t h e s e e f f e c t s might be v e r y s i g n i f i c a n t .  1969)  Consequently, i t  d e c i d e d t o study t h e s e e f f e c t s .  Review o f the  Ecological  effects of  A forest consists  Literature^" ,  clearcutting not  o n l y o f t r e e s but  l i v i n g organisms.(trees, a l l other plants,  Review c o n c l u d e d September,  1974.  o f the  was  streamwater chemistry,  r e s u l t s o f the  at. , 1968;  to  t o t a l assemblage  a n i m a l s , and  microbes) as  of well  3  as t h e t o t a l p h y s i c a l ganisms l i v e .  environment  A l l these l i v i n g  ( s o i l , a i r , and water) i n which t h e o r -  and n o n - l i v i n g  components i n t e r a c t w i t h  each o t h e r , f o r m i n g a v e r y complex system c a l l e d an ecosystem  (Tansley,  1935). Due usually and  t o the great d i v e r s i t y within very d i f f i c u l t  each c l e a r c u t  t o generalize  condition  plant the  about t h e e f f e c t s o f c l e a r c u t t i n g  a r e a s h o u l d be c o n s i d e r e d s e p a r a t e l y .  c l e a r c u t t i n g on ecosystems w i l l and  and between ecosystems, i t i s  depend on many f a c t o r s  The e f f e c t s o f such as t h e t y p e  o f t h e s o i l and t h e f o r e s t f l o o r , t h e topography,  and a n i m a l communities p r e s e n t , t h e t y p e o f equipment used, and  season o f t h e y e a r when c l e a r c u t t i n g took p l a c e .  F o r any one e f f e c t  o f c l e a r c u t t i n g on a p a r t i c u l a r f o r e s t ecosystem i t i s u s u a l l y t o f i n d t h e o p p o s i t e e f f e c t on a n o t h e r f o r e s t  (1)  E f f e c t s on t h e s o i l  (a)  Soil  the  climate,  e r o s i o n - Dyrness  literature pertaining  ecosystem.  (1967) and R i c e et al, (1972) have reviewed  to erosion of forest  E x t e n s i v e c l e a r c u t t i n g on s l o p e s i s l i k e l y e r o s i o n and s u r f a c e r u n o f f Froehlich,  possible  soils. t o increase s o i l surface  (Bethlahmy, 1967; C u r r y , 1973; Dyrness, 1967;  1973; R i c e et al., 1972; S h e r r y , 1954; Swanston, 1971a;  T a c k l e , 1962; W i l l i n g t o n ,  1968).  T h i s i s t h e r e s u l t o f lower  infiltration  r a t e s w h i c h may be due t o : 1,  A decrease i n s o i l p o r o s i t y  when s o i l p a r t i c l e s a r e s p l a s h e d o r  washed i n t o p o r e s by r a i n o r snowmelt.  T h i s may be enhanced by t h e r e -  m o v a l o f any v e g e t a t i v e c o v e r o r o r g a n i c d e b r i s , the  d i r e c t impact o f r a i n d r o p s .  exposing mineral s o i l t o  4  2.  The  induction of hydrophobicity  t h r o u g h o u t A l a s k a and  t h e western U.S.  d u r i n g d r y summer p e r i o d s Jamieson, 1969;  in soils.  Coarse t e x t u r e d  frequently e x h i b i t hydrophobicity  (DeBano et al. , 1967;  Krammes and Debano, 1965;  Foggin  and DeBano,  Meeuwig, 1971).  o b s e r v e d water r e p e l l e n c y i n the decomposing l i t t e r under fir  f o r e s t s i n Montana and  southern  aspects.  By  the s o i l  3,  the s o i l  o f hydrophobic An  (1973)  larch-Douglas-  s u r f a c e to more heat t h r o u g h r e -  and by d e p o s i t i n g more decomposing m a t e r i a l  s u r f a c e , i n t h e form o f s l a s h , c l e a r c u t t i n g my  formation  DeByle  1971;  found i t t o be more common on the warmer  exposing  moval o f v e g e t a t i v e c o v e r  soils  facilitate  on  the  soils.  i n c r e a s e i n t h e amount o f exposed bedrock r e s u l t i n g i n l o c a l  concentration of runoff. These h y d r o l o g i c a l e f f e c t s are n o t u n i v e r s a l , however. s t u d i e s have found t h a t c l e a r c u t t i n g has capacity  (e.g. Dyrness et al. , 1957;  little  Lull  and R e i n h a r t ,  c l e a r t h a t the degree o f s o i l d i s t u r b a n c e , surface erosion, w i l l  e f f e c t on  (Dyrness,  infiltration  1972)  and  i t is  and hence the degree o f  soil  depend t o a l a r g e e x t e n t on t h e h a r v e s t i n g t e c h -  n i q u e used, w i t h h i g h l e a d systems c a u s i n g l e s s d i s t u r b a n c e logging  Some  1972;  than t r a c t o r  R i c e et al. , 1972).  '  C l e a r c u t t i n g causes a p r o g r e s s i v e d e t e r i o r a t i o n o f the r o o t tems r e s p o n s i b l e f o r s o i l s t a b i l i t y the i n c r e a s e i n s o i l water c o n t e n t duce mass movements o f s o i l 1950;  F r e d r i k s e n , 1970;  s t o n , 1971a,b), southwestern B.C.,  on  steep slopes.  f o l l o w i n g v e g e t a t i o n removal, may  (Bishop and  S t e v e n s , 1964;  O ' L o u g h l i n , 1974;  O'Loughlin  T h i s , together  syswith in-  C r o f t and Adams,  R i c e and Krammes, 1971;  Swan-  (1972) s t u d y i n g mass movements o f s o i l i n  f o u n d t h a t l a n d s l i d e s not a s s o c i a t e d w i t h roads were  5  mainly on l o n g u n i f o r m s l o p e s w i t h g r a d i e n t s o f more than 30° u n d e r l a i n by poorly drained podzols.  Large  than on u n d i s t u r b e d s l o p e s .  l a n d s l i d e s were more f r e q u e n t on  He  concluded t h a t :  clearcuts  "Current f o r e s t  cutting  and r o a d b u i l d i n g p r a c t i c e s on t h e s t e e p s l o p e s o f B r i t i s h Columbia's Coast Mountains a r e not c o m p a t i b l e w i t h s e n s i b l e mountainland  management  which f o s t e r s p r o t e c t i o n o f the s o i l r e s o u r c e " , and recommended t h a t t h e r e be no c l e a r c u t t i n g on a) in altitude,  c)  s l o p e s g r e a t e r than 35°, b)  f o r e s t s o v e r 1000  f o r e s t s a d j a c e n t t o mountain streams,  and d)  m  f o r e s t s on  p o o r l y d r a i n e d s l o p e s and i n l a r g e d r a i n a g e d e p r e s s i o n s s u b j e c t t o p e r i o dic  saturation. There i s g e n e r a l agreement among a l l workers i n t h e f i e l d  of  soil  e r o s i o n , t h a t , o f a l l man's a c t i v i t i e s i n f o r e s t s , r o a d b u i l d i n g i s t h e major cause o f e r o s i o n . (b)  S o i l moisture  r e l a t i o n s - The  removal o f v e g e t a t i o n d e c r e a s e s  evapo—  t r a n s p i r a t i o n and i n t e r c e p t i o n water l o s s e s t o t h e atmosphere t e n d i n g t o increase s o i l moisture In  B.C.,  moisture els  Baker  levels  (Cochran,  (1968) and K n i g h t  1969;  J e f f r e y , 1970;  (1964) have b o t h found  levels after clearcutting.  Baker  Patric,  1973),  increases i n s o i l  (1968) found t h a t m o i s t u r e  o f c l e a r c u t and burned s o i l s i n s o u t h e a s t e r n B.C.  were h i g h e r  lev-  than  those o f u n d i s t u r b e d s o i l s d u r i n g the growing season whereas t h e r e v e r s e was  t r u e d u r i n g the r e s t o f the y e a r .  s u l t s the f i r s t year a f t e r l o g g i n g . l e s s a v a i l a b l e moisture  (1964) o b t a i n e d s i m i l a r r e -  However, i n subsequent y e a r s he  found  i n the s u r f a c e h o r i z o n s o f s o i l s under c l e a r c u t s  than i n u n d i s t u r b e d s o i l s .  T h i s he a t t r i b u t e d t o the r a p i d i n v a s i o n o f  s h a l l o w r o o t i n g t r a n s p i r i n g herbs and to  Knight  shrubs and the added exposure  due  s t a n d removal which i n c r e a s e d e v a p o r a t i o n i n the c l e a r c u t compared t o  . the u n d i s t u r b e d  forest.  6  S o i l moisture  i n c r e a s e s f o l l o w i n g c l e a r c u t t i n g may  result in a  r i s e o f t h e s o i l water t a b l e which can r e s u l t i n f l o o d i n g o f the s u r f a c e i n wet  sites  (Bay,  Hoover, 1955).  1967;  H e i k u r a i n e n and PaivMnen, 1970;  T h i s has been o b s e r v e d  e s t s o f A l b e r t a ( J a r v i s et at., v e r s e l y , t h e water t a b l e may area of mineral s o i l .  i n the s p r u c e - s u b a l p i n e f i r f o r Lees,  be lowered  T h i s was  a t h i c k moss c o v e r i n Sweden  1966;  T r o u s d e l l and  1960;  L e e s , 1970).  Con-  i f c l e a r c u t t i n g exposes a l a r g e  observed  f o l l o w i n g burning of s i t e s with  (Ahlgren and A h l g r e n , 1960).  In the u n d i s -  t u r b e d c o n d i t i o n the s o i l d i d n o t f r e e z e c o m p l e t e l y i n w i n t e r so t h a t t h e s p r i n g thaw was  absorbed  i n t o t h e ground k e e p i n g t h e water t a b l e h i g h .  B u r n i n g , which exposed m i n e r a l s o i l , r e s u l t e d i n complete f r e e z i n g o f t h e s o i l i n w i n t e r p e r m i t t i n g water from the s p r i n g thaw t o run o f f t h e Removal o f t h e s u r f a c e o r g a n i c s o i l and s o i l compaction i n c r e a s e the depth and p e r s i s t e n c e o f s o i l 1972) (c)  which may  freezing  site.  have been shown t o  (Thorud and Duncan,  r e s u l t i n more s u r f a c e r u n o f f (Dunne and B l a c k , 1971),  S o i l m i c r o c l i m a t e - C l e a r c u t t i n g , as p r a c t i s e d i n c o a s t a l B.C., seems  u n l i k e l y t o a f f e c t macroclimate  significantly.  Only i n s p e c i a l  circum-  s t a n c e s w i t h v e r y e x t e n s i v e c l e a r c u t t i n g might a s l i g h t d e c r e a s e p r e c i p i t a t i o n occur  ( G o l d i n g , 1970).  The  i n nearby  removal o f t r e e s u s u a l l y  causes  changes i n t h e c l i m a t e near t h e s o i l s u r f a c e , however. 1.  Temperature extremes may  s t a t e d t h a t s u r f a c e temperature c l e a r c u t , Powell  be g r e a t e r .  A l t h o u g h Cochran  (1969)  extremes i n c r e a s e w i t h the s i z e o f the  (1971), i n a l i t e r a t u r e review o f the e f f e c t s o f  clear-  c u t t i n g on c l i m a t i c f a c t o r s , found t h a t the i n f l u e n c e o f the f o r e s t most c l i m a t i c p a r a m e t e r s r a r e l y extends  more than 2-3  on  times the h e i g h t  7  o f the t r e e s i n t o a c l e a r c u t , so t h e c l i m a t i c c o n d i t i o n s i n t h e open  will  remain p r a c t i c a l l y c o n s t a n t w i t h i n c r e a s i n g s i z e o f the c l e a r c u t , once i t s d i a m e t e r exceeds 4-6  times t h e h e i g h t o f the t r e e s .  Lower temperature minima g i v e r i s e t o more i n t e n s e and f r o s t s which can steep h i l l s i d e s et al.,  1958;  Zasada and  cause f r o s t h e a v i n g (Cochran, 1969;  o f s e e d l i n g s o r s o i l slumping  Hale,  1950;  Remezov and Pogrebnyak, 1969,  on  J a r v i s et al. , "1966; P i e r c e ch. 6 and  8; Waldron,  1966;  Gregory, 1969).  Increased  s o i l temperatures d u r i n g t h e warmer months may,  p a r t i c u l a r l y h o t s i t e s such as s o u t h - f a c i n g s l o p e s , be prevent  earlier  germintion  k i n s , 1937).  or to k i l l  ( I s s a c , 1938;  I s a a c and  to  Hop-  However, i n c o l d e r r e g i o n s , i n c r e a s e d temperatures may  b e n e f i c i a l t o p l a n t growth permafrost  seedlings  so h i g h as  on  (Ahlgren and A h l g r e n ,  1960;  r e g i o n s i n c r e a s e d s o i l temperatures can  t r e a t o f the permafrost  layer, increasing  be  L u t z , 1956).  In  cause a downward r e -  the p o t e n t i a l p r o d u c t i v i t y of  a s i t e by making a g r e a t e r amount o f s o i l a v a i l a b l e t o p l a n t r o o t s . thermore, i n c r e a s e d s o i l temperature i n c r e a s e s the r a t e o f c h e m i c a l t h e r i n g and  biological activity,  r e l e a s e t o the s o i l 2. tion  (although  and L u l l ,  1965)  1970).  s i g n i f i c a n t l y reduce i n c i d e n t short-wave r a d i a -  long-wave r a d i a t i o n i s d e p l e t e d v e r y l i t t l e ) and  wea-  thus i n c r e a s i n g t h e r a t e o f n u t r i e n t  (Likens et al.,  Tree canopies  Fur-  (Reifsnyder  i n c i d e n t s o l a r r a d i a t i o n under f o r e s t canopies  is  o f t e n l e s s than 10% o f t h a t i n nearby c l e a r c u t s ( V e z i n a and Pech, 1964). Thus, c l e a r c u t t i n g f a v o u r s t h e growth o f the more shade i n t o l e r a n t s p e c i e s c h a r a c t e r i s t i c of a f o r e s t ' s e a r l i e r successional  stages.  8  3,  F o r e s t s s i g n i f i c a n t l y reduce wind v e l o c i t i e s r e l a t i v e t o those i n  open a r e a s .  Thus, wind v e l o c i t i e s i n c l e a r c u t s a r e i n c r e a s e d and i n t e n s e  t u r b u l e n c e may d e v e l o p  ( K i t t r e d g e , 1962; P o w e l l ,  1971; Remezov and P o g r e -  bnyak, 1969, c h . 8) . 4.  Vegetation  removal u s u a l l y d e c r e a s e s i n t e r c e p t i o n l o s s e s o f p r e -  c i p i t a t i o n r e s u l t i n g i n an i n c r e a s e i n t h e amount o f p r e c i p i t a t i o n ing  the s o i l  1969,  surface  ch. 8 ) .  ( J e f f r e y , 1970; P o w e l l ,  1971; Remezov and Pogrebnyak,  T h i s may have l i t t l e o r no e f f e c t , may be b e n e f i c i a l by  s u p p l y i n g more m o i s t u r e f o r p l a n t growth, o r may be d e t r i m e n t a l s o i l erosion occurs. to  reach-  Detrimental  high i n t e n s i t y r a i n f a l l  areas o f low i n t e n s i t y Increased  e f f e c t s a r e more l i k e l y  i f increased  i n areas  subject  whereas b e n e f i c i a l e f f e c t s a r e more l i k e l y i n  rainfall.  snow a c c u m u l a t i o n  o c c u r s on c l e a r c u t s n o t o n l y due t o  r e d u c e d i n t e r c e p t i o n b u t a l s o t o wind e f f e c t s which r e d i s t r i b u t e snow i n c l e a r i n g s i n f o r e s t s (Powell, 1971). (d)  '  C h e m i c a l p r o p e r t i e s - As d i s c u s s e d above, c l e a r c u t t i n g has t h e f o l -  lowing  effects:  1.  I t exposes t h e s o i l s u r f a c e t o more h e a t and m o i s t u r e which a c -  celerates s o i l m i c r o b i a l a c t i v i t y , r e s u l t i n g i n greater rates o f organic m a t t e r d e c o m p o s i t i o n and concomitant i n c r e a s e s i n t h e s u p p l y o f a v a i l a b l e chemical n u t r i e n t s . 2.  By e x p o s i n g  any m i n e r a l  s o i l , a t t h e s u r f a c e t o g r e a t e r tempera-  t u r e extremes and i n c r e a s i n g s o i l m o i s t u r e l e v e l s , c l e a r c u t t i n g may i n crease  the r a t e o f chemical  3. soil.  weathering or inorganic  substrata.  By removing v e g e t a t i o n , i t d e c r e a s e s n u t r i e n t uptake from t h e  9  4.  By  decreasing  evapotranspiration  and  interception losses, i t  i n c r e a s e t h e amount o f water p a s s i n g t h r o u g h the All  soil.  these f a c t o r s i n d i c a t e t h a t c l e a r c u t t i n g w i l l  o f n u t r i e n t c h e m i c a l s down t h r o u g h the s o i l , as was Greenland  (1960) and O v i n g t o n  T h i s aspect  Gessel,  1965;  i n c r e a s e the  suggested by Nye  C o l e et at.,  1973;  co-workers i n Washington  Gessel  p l a n t a t i o n on g r a v e l l y sandy loam p o d z o l s  low  and  Cole,  1965).  the r o o t i n g zone  c u t t i n g on  Douglas-fir  very  slight  calcium  l o s s e s were  be-  during increased  than n i t r o g e n and p o t a s s i u m l o s s e s .  (1973), i n a r e v i e w o f w o r l d l i t e r a t u r e on the e f f e c t s o f c l e a r s o i l p r o d u c t i v i t y , quoted s e v e r a l o t h e r workers who  f o u n d t h a t c l e a r c u t t i n g can pedon.  These a u t h o r s  N u t r i e n t f l u x e s were g r e a t e s t  months and phosphorus and  t o a greater extent Curry  (36 i n c h e s ) ,  (Cole  d i d i n c r e a s e the amount o f chem-  t h r o u g h the s o i l a l t h o u g h the i n c r e a s e was  the wetter winter  and  o f c l e a r c u t t i n g has been r e c e i v i n g i n c r e a s i n g a t t e n t i o n  used t e n s i o n l y s i m e t e r s t o show t h a t c u t t i n g a 4 3 - y e a r - o l d  i c a l s passing  flow  (1962).  and has been w e l l documented by C o l e and and  may  i n c r e a s e the f l o w o f c h e m i c a l s down the  Remezov and Pogrebnyak  r e s u l t s occur  have a l s o  (1969, ch. 7 and  soil  8) i n d i c a t e d t h a t s i m i l a r  a f t e r clearcutting.or p a r t i a l cutting i n Russia.  Firsova  (1965) f o u n d t h a t c l e a r c u t t i n g on sod p o d z o l i c s o i l s i n the R u s s i a n T r a n s u r a l s l e d t o a change n o t  so much i n the t o t a l q u a n t i t y as i n the  t i v e q u a n t i t i e s o f water s o l u b l e c h e m i c a l s i n the E x p e r i m e n t a l F o r e s t i n the n o r t h e a s t e r n stimulated  U.S.,  soil.  vegetation  A t Hubbard Brook removal g r e a t l y  the a c t i v i t y o f n i t r i f y i n g b a c t e r i a l e a d i n g t o a l a r g e  i n n i t r a t e ion concentration  rela-  increase  i n s o i l l e a c h i n g waters accompanied by  increases i n cation concentrations  ( L i k e n s et  at.,  1970;  Bormann et  large at.,  10  1968).  A l t h o u g h the  i n i t i a l r e s u l t s a t Hubbard Brook were f o r a v e r y a t y p i -  c a l f o r e s t treatment, recent  studies of regular  commercial c l e a r c u t t i n g i n  t h e same f o r e s t a r e a have p r o d u c e d v e r y s i m i l a r r e s u l t s (Hornbeck et 1973;  P i e r c e et al. , 1972).  C l e a r c u t t i n g i n Sweden has  enhance n i t r i f i c a t i o n i n s o i l s The  increased  c r e a s e d s o i l pH,  increased  from the  l o s s e s by soil  i s l i v i n g vegetation  s o i l b e f o r e they are  successional  species  f o l l o w i n g c l e a r c u t t i n g may p r e s e n t t o withdraw t h e  l e a c h e d away.  But  lesser vegetation  c a n t l o s s o f n u t r i e n t s from t h e  saturation ing  (Cole,  ( G r i e r , 1972).  types of s o i l s are  after clearcutting:  i f the  logging operations  An  increased  be  nutrients  or retarded  s o i l may  occur.  regeneration  a)  1963;  Nye  and  e s p e c i a l l y vulnerable  des-^  most  s o i l s w i t h a low or a high  (1972) c o n s i d e r e d to excessive  s h a l l o w t o bedrock s o i l s ; b)  in  then s i g n i f i -  T h i s l o s s w i l l be  Greenland,. 1960)  P i e r c e et-al.  have  cation  base  t h a t the nutrient  followlosses  s o i l s which have  t h i n l a y e r s o f u n i n c o r p o r a t e d humus o v e r l y i n g m i n e r a l h o r i z o n s ; s k e l e t a l s o i l s on  has  available nutrients  d r a m a t i c i n a r e a s c h a r a c t e r i z e d by heavy r a i n s and exchange c a p a c i t y  In-  Indeed, r a p i d growth o f e a r l y  a c c u m u l a t i o n o f the  Bormann, 1972).  t r o y e d much o f the  i n s o i l pH.  f o l l o w i n g c l e a r c u t t i n g t e n d s t o minimize n u t r i e n t  v i g o r o u s uptake and  (Marks and  increase  (1972).  chemical a v a i l a b i l i t y  b e n e f i c i a l i f there  cause an  y e a r s a f t e r c l e a r c u t t i n g i n c o a s t a l Washington,  been r e c o r d e d by G r i e r The  a l s o been shown t o  (Popovic, 1974),  f l o w o f c h e m i c a l s may  two  at.,  c)  coarse  steep t e r r a i n . n u t r i e n t a v a i l a b i l i t y w i l l not n e c e s s a r i l y b e n e f i t  p l a n t s , however, s i n c e p l a n t s have been shown-to sometimes t a k e up  exces-  s i v e q u a n t i t i e s o f n u t r i e n t s w i t h o u t showing a c o r r e s p o n d i n g i n c r e a s e  in  11  growth  (Baker and  P h e l p s , 1969;  r e n d e r e d a v a i l a b l e may f e r t i l i t y may  require a sustained  Early successional  from s u c h s p e c i e s  As  1969;  the s o i l  nutrient-rich l i t t e r i n nitrogen  Tarrant  and  Trappe, 1971;  period  through-  as w e l l as o t h e r  nu-  Tarrant  et al.,  1968;  Z a v i t k o v s k i and Newton, 1968).  supply  sodium budgets o f a watershed and  work which d i r e c t l y measures  o f c h e m i c a l s t o the  a t t r i b u t i n g net  s o i l by  herbicides increased  about t h r e e  Commercial c l e a r c u t t i n g was  fold  min-  changes  sodium l o s s e s s o l e l y  t o c h e m i c a l w e a t h e r i n g , have c a l c u l a t e d t h a t d e v e g e t a t i o n  o f the m i n e r a l s  and  However, the Hubbard Brook w o r k e r s , by o b s e r v i n g  shed by c u t t i n g and  Site  nutrient losses following clearcutting  the e f f e c t s o f c l e a r c u t t i n g on the  in  The  y e t , t h e r e appears t o be no p u b l i s h e d  e r a l weathering.  l i m i t i n g growth.  such as Ceanothus o r Atnus which have r o o t n o d u l e s  enriches  1968;  are  availability.  t r i e n t s , h e l p i n g t o o f f s e t any  T a r r a n t et al.,  n u t r i e n t s which  s p e c i e s which come i n soon a f t e r c l e a r c u t t i n g i n  often include species  ( F r a n k l i n et al.,  The  r e l e a s e of n u t r i e n t s over a long  containing nitrogen-fixing bacteria. fall  1971).  n o t be t h e f a c t o r s w h i c h a r e  r a t h e r t h a n sudden f l u s h e s o f  B.C.  Wells,  of t h e i r water-  the r a t e o f c h e m i c a l w e a t h e r i n g  (Johnson et al.,  1968;  Likens  e x p e c t e d t o cause a s i m i l a r b u t  et al. , 1970).  smaller  increase  (Bormann et al. , 1968) . In general,  c l e a r c u t t i n g t e n d s t o i n c r e a s e the amount o f  moving i n s o l u t i o n t h r o u g h t h e on a v a r i e t y o f m e t e o r o l o g i c a l , c u t t i n g removes one other  soil,  chemicals  a l t h o u g h t o v a r y i n g degrees depending  b i o l o g i c a l , and  chemical f a c t o r s .  component o f a multicomponent p l a n t community.  components a r e n o t too s e r i o u s l y d i s t u r b e d by the  logging  Clear— I f the  operations,  12  they w i l l be a b l e t o u t i l i z e any  i n c r e a s e d n u t r i e n t s u p p l i e s i n the  soil  and  t h e b i o l o g i c a l n u t r i e n t c y c l e on the  s i t e w i l l remain i n o p e r a t i o n .  The  degree t o which c l e a r c u t t i n g l e a d s t o l e a c h i n g l o s s e s of n u t r i e n t s  from t h e ecosystem w i l l depend t o a c o n s i d e r a b l e e x t e n t on t h e degree t o which t h e v a r i o u s components of t h e system have been d i s t u r b e d . (2)  E f f e c t s on l i v i n g  (a)  Tree pathogens:  organisms d i s e a s e and  i s c o n s i d e r e d by C e r e z k e  i n s e c t s - C l e a r c u t t i n g mature f o r e s t s  (1971) t o have an immediate d e v a s t a t i n g e f f e c t .  upon many i n s e c t p o p u l a t i o n s s i n c e t h e i r f o o d s o u r c e habitat destroyed  or a l t e r e d .  The  t o cause i n s e c t p e s t o u t b r e a k s , who  i s e l i m i n a t e d and  their  s l a s h l e f t by c l e a r c u t t i n g i s u n l i k e l y  as i l l u s t r a t e d by Graham and K n i g h t  s t a t e d i n t h e i r f o r e s t entomology t e x t  (p. 173):  "The  (1965)  g e n e r a l con-  sensus o f o p i n i o n i s t h a t hardwood s l a s h i s almost never a b r e e d i n g  place  f o r i n s e c t s t h a t a t t a c k l i v i n g t r e e s . . Even c o n i f e r o u s s l a s h i s n o t  so  s e r i o u s a menace as has been sometimes s t a t e d . e v e r , when i t p r e s e n t s  important  problems.  As  T h e r e a r e i n s t a n c e s , howl o n g as l o g g i n g i s g o i n g  on and f r e s h s l a s h i s c o n t i n u a l l y b e i n g s u p p l i e d by s u c c e s s i v e the i n s e c t s breeding f o r each g e n e r a t i o n .  i n t h i s m a t e r i a l w i l l f i n d adequate f e e d i n g p l a c e s When l o g g i n g o p e r a t i o n s end  s l a s h i n s e c t s , because o f a s c a r c i t y o f f o o d , may Such o u t b r e a k s  operations  a r e u s u a l l y s p o r a d i c and  i n a l o c a l i t y , then  the  attack standing t r e e s . . . .  seldom, o c c a s i o n g r e a t l o s s e s . "  I n s e c t s which have o c c a s i o n a l l y become s e r i o u s p e s t s a f t e r  clearcutting  i n c l u d e the bark b e e t l e s  Graham, p.  (Graham and K n i g h t , p.  330,  1965;  220,  1963) . I n j u r i o u s l o g g i n g p r a c t i c e s which s c a r o r break t h e r o o t s o f r e s i d u a l trees predispose  t h e s e t r e e s t o damage from i n s e c t s , p a r t i c u l a r l y  from  13  bark b e e t l e s , p.  ambrosia b e e t l e s ,  230, 1965).  ject trees  and r o o t - e a t i n g  weevils  (Graham and K n i g h t ,  Sometimes t h e opening o f a s t a n d b y c l e a r c u t t i n g may sub-  t o the e f f e c t s of desiccation  and h e a t i n g o f t h e s o i l w i t h sub-  sequent r o o t  i n j u r y and s u s c e p t i b i l i t y t o b a r k - m i n i n g i n s e c t s  220,  Windfall  1963).  gin forests.  o f "edge" t r e e s  The windthrown  certain beetles,  trees  commonly f o l l o w s  (Graham, p.  clearcutting  in vir-  can provide i d e a l breeding s i t e s f o r  such as t h e Engelmann s p r u c e b e e t l e i n t h e o l d  spruce-  s u b a l p i n e f i r f o r e s t s i n t h e i n t e r i o r o f B.C. (Alexander, 1964; Graham and K n i g h t , p . 340, 1965). Cerezke  (1971), i n a r e c e n t l i t e r a t u r e r e v i e w o f t h e e f f e c t s o f c l e a r -  c u t t i n g on i n s e c t p e s t s i n A l b e r t a , f i t s insect populations but that forests  a r e d e v e l o p e d on c l e a r c u t  l i s t e d several  insect  insects  not  are favoured i f s i n g l e  areas.  Graham and K n i g h t  Cerezke  (1973) d i s a g r e e d , however, c l a i m i n g  necessarily  (1971) l i s t e d  (p. 229, 1965)  several  ser-  more.  t h a t man-made pure stands a r e  more prone t o i n s e c t a t t a c k t h a n n a t u r a l  Clearcutting  species  s p e c i e s which, once a l m o s t unknown, have become  i o u s p e s t s i n man-made pure s t a n d s . Stark  c o n c l u d e d t h a t c l e a r c u t t i n g r a r e l y bene-  stands.  appears t o have s i m i l a r e f f e c t s on f o r e s t d i s e a s e s a s  i t has on i n s e c t p e s t s .  Thus, a l t h o u g h s l a s h p r o v i d e s a s u b s t r a t e n e c e s -  s a r y f o r t h e development o f f r u i t i n g b o d i e s o f many f u n g a l d i s e a s e s , such as t h o s e which cause damping o f f , r o o t r o t s , stem and f o l i a g e r u s t s , and bark c a n k e r s , s u c h d i s e a s e s p r o b a b l y seldom cause s e r i o u s  mortality  t u r a l l y r e g e n e r a t e d a r e a s b u t a r e more l i k e l y t o cause s e r i o u s in artificial 1971).  r e g e n e r a t i o n of monocultures  mortality  (Boyce, p. 515, 1961; Loman,  Damping o f f d i s e a s e s i n s e e d l i n g s appear i n e v i t a b l e a f t e r  c u t t i n g , although o f v a r i a b l e  importance  i n na-  (Loman, 1971).  clear-  14  Loman (1971), i n a recent l i t e r a t u r e review of the e f f e c t s of c l e a r cutting on tree diseases i n Albertan f o r e s t s , concluded that  extensive  clearcuts eliminate a l l f o r e s t diseases associated with mature f o r e s t s . Thus, heartwood stains i n spruce (Loman, 1961) and decay i n even-aged stands of pine, spruce, and Douglas-fir are eliminated 1971).  (Boyce, p. 378, 1961; Loman,  S i m i l a r l y , t o t a l c l e a r c u t t i n g can remove a l l sources of dwarf mis-  t l e t o e i n f e c t i o n (Boyce, p. 335, 1961; Loman, 1971; Parmeter, 1973; Smith and Baranyay, 1971).  Clearcutting can remove the i n f e c t i o n sources o f stem  canker on lodgepole pine which a f f l i c t s immature trees (Loman, 1971).  Fungi  which decay slash are promoted, of course (Loman, 1971). Injuries i n f l i c t e d on trees during c l e a r c u t t i n g operations may allow decay organisms to enter the injured trees (Boyce, p. 374, 1961).  Thin-  barked species such as western hemlock, s i t k a spruce, and true f i r s are p a r t i c u l a r l y vulnerable  (Wright and Isaac, 1956).  A f t e r a stand i s opened  up, sunscald may occur on the r e s i d u a l trees with decay i n f e c t i o n often following (Boyce, p. 374, 1961). In general, however, diseases a r i s i n g from c l e a r c u t t i n g appear to be r e l a t i v e l y unimportant.  I t appears that i t i s not c l e a r c u t t i n g alone, but  c l e a r c u t t i n g together with subsequent s i l v i c u l t u r a l treatments, which w i l l determine the importance of attacks by tree diseases on trees. 374, 1961) concluded that:  Boyce (p.  " I t i s u n l i k e l y i n most f o r e s t types that the  i n f e c t i o n of l i v i n g trees by fungi from slash w i l l be serious enough t o warrant the increased expense o f disposing of large c u l l material on cutover areas, since generally the fungi causing most of the decay i n l i v i n g trees are not abundant even on large s l a s h . " . Parmeter  (1973) has a r r i v e d  15  at  a s i m i l a r c o n c l u s i o n , as had C h i l d s  (1939), f o r the west c o a s t S i t k a  s p r u c e , w e s t e r n hemlock, and D o u g l a s - f i r f o r e s t s . (b)  S o i l m i c r o - and meso-organisms - Changes i n s o i l temperatures,  t u r e r e l a t i o n s , and n u t r i e n t a v a i l a b i l i t y may and s p e c i e s c o m p o s i t i o n o f s o i l organisms, R u s s i a and  mois-  i n d u c e changes i n numbers  as has been w e l l documented i n  Europe.  Abundant e v i d e n c e i s p r e s e n t e d i n Sukachev's "Fundamentals o f F o r e s t Biogeocoenology"  i l l u s t r a t i n g how  c l e a r c u t t i n g can change b o t h  s p e c i e s num-  b e r s and s p e c i e s c o m p o s i t i o n o f s o i l m i c r o b i a l p o p u l a t i o n s (Egorova et 1964).  Egorova  (1970b) found t h a t c l e a r c u t t i n g oak f o r e s t s i n R u s s i a caused  an i n c r e a s e i n t h e p o p u l a t i o n o f s p o r e - f o r m i n g b a c t e r i a i n t h e l i t t e r b u t a d e c r e a s e i n t h e p o p u l a t i o n s o f non-spore-forming f u n g i , and a c t i n o m y c e t e s .  layer  bacteria, microscopic  In t h e m i n e r a l s o i l , c l e a r c u t t i n g caused a  de-  c r e a s e i n a n a e r o b i c m i c r o b i a l a c t i v i t y b u t an i n c r e a s e i n a c t i v i t y o f spore- forming b a c t e r i a , a e r o b i c cellulose-decomposing b a c t e r i a , c e t e s , and m i c r o s c o p i c f u n g i .  The a c t i v i t y o f t h e m i c r o f l o r a was aspen s t a n d s Egorova  non-  actinomy-  However, as oak r e g e n e r a t i o n grew up,  s o i l m i c r o f l o r a gradually reverted to t h e i r pre-clearcutting  In  the  composition.  determined p r i m a r i l y by s o i l  moisture.  (1970a) found t h a t c l e a r c u t t i n g i n c r e a s e d pop-  u l a t i o n s o f b a c t e r i a and a c t i n o m y c e t e s and  significantly affected  the  microscopic fungal populations. In  al.,  c e n t r a l Europe,  Gretschy  (1949) found t h a t a r t h r o p o d abundance  f e l l t o h a l f the o r i g i n a l v a l u e soon a f t e r c l e a r c u t t i n g w i t h the t y p e s and p r o p o r t i o n s o f s p e c i e s r e m a i n i n g unchanged.  Three y e a r s  after  16  c u t t i n g , the abundance had d e c r e a s e d had  changed as w e l l .  Moritz  i n the species composition changed, w i t h  s t i l l more and t h e s p e c i e s  composition  (1965) found t h a t c l e a r c u t t i n g caused no change  o f O r i b a t i d s although  abundance r e l a t i o n s  some o f t h e l e s s numerous p r e - l o g g i n g s p e c i e s becoming dom-  inants . In the northeastern  U.S.,  one study  on c l e a r c u t t h a n on f o r e s t e d areas b a r d Brook study  ( L i k e n s et al.,  found h i g h e r nematode  populations  (Shigo and Y e l e n o s k y , 1960) and t h e Hub-  1969; P i e r c e et al.,  1972; Smith et  al.,  1968 s u g g e s t s t h a t c l e a r c u t t i n g t h e deciduous hardwood f o r e s t s o f t h a t r e g i o n i n c r e a s e s t h e abundance o f n i t r i f y i n g b a c t e r i a and p r o b a b l y t h e abundance o f s u l p h u r - o x i d i z i n g b a c t e r i a . al.,  I t was c o n s i d e r e d  decreases (Smith  1968) t h a t t h e i n c r e a s e d abundance o f n i t r i f y i n g b a c t e r i a was  due t o one o r more o f :  enhanced a v a i l a b i l i t y o f ammonium i o n s  et  probably  resulting  from i n c r e a s e d h e t e r o t r o p h i c a c t i v i t y ; e l i m i n a t i o n o f n u t r i e n t uptake by v e g e t a t i o n , and removal o f d i r e c t e f f e c t s such as i n h i b i t i o n o f chemautot r o p h s by s u b s t a n c e s produced by t h e v e g e t a t i o n .  A d e c r e a s e i n abundance  o f s u l p h u r - o x i d i z i n g b a c t e r i a was c o n s i d e r e d most l i k e l y due t o h i g h n i t r a t e c o n c e n t r a t i o n s b e i n g t o x i c t o t h e s e b a c t e r i a ( L i k e n s et al., 1970). C l e a r c u t t i n g has been found t o have l i t t l e o r no d e l e t e r i o u s e f f e c t s on m y c o r r h i z a l Vlug  f u n g i o r on t h e f o r m a t i o n  s e v e r e l y reduced t h e p o p u l a t i o n d e n s i t i e s o f a l l a r t h r o -  and o f b o t h C o l l e m b o l a  a f t e r o n l y two y e a r s . o f ways.  (Wilde, 1968).  (1972) found t h a t c l e a r c u t t i n g i n t h e U n i v e r s i t y o f B.C. R e s e a r c h  F o r e s t , near Haney, pods  of mycorrhizae  and A c a r i a l t h o u g h  r e c o v e r y was  significant  D i f f e r e n t t a x a were a f f e c t e d by l o g g i n g i n a v a r i e t y  17  M i c r o - and meso-organisms are p r i m a r i l y r e s p o n s i b l e i z a t i o n o f n u t r i e n t s and  t h e i r r e t u r n t o the s o i l and,  are d i r e c t l y i n v o l v e d i n s o i l p r o d u c t i v i t y . e f f e c t s on p o p u l a t i o n s has  f o r the  consequently,  C l e a r c u t t i n g has  of t h e s e o r g a n i s m s .  mineral-  quite variable  None o f t h e s e e f f e c t s , however,  been shown t o i n t e r f e r e w i t h r e f o r e s t a t i o n o f c l e a r e d a r e a s and  b i a l populations est develops  micro-  u s u a l l y r e t u r n to the p r e - c u t t i n g b a l a n c e as the new  (Egorova et ali,  t o a marked i n c r e a s e  1964).  In some c a s e s ,  for-  c l e a r c u t t i n g has  led  i n m i c r o b i a l a c t i v i t y with concomitant increases  nutrient availability. increased  they  However, the Hubbard Brook s t u d y has  in  shown t h a t  abundance o f m i c r o b e s w i l l not n e c e s s a r i l y i n c r e a s e  long-term  s o i l p r o d u c t i v i t y because i n c r e a s e s i n numbers of n i t r i f y i n g b a c t e r i a r e sulted i n considerable P i e r c e et at., (c)  (Likens et at.,  1970;  1972).  Vertebrates 1.  and  l o s s o f n u t r i e n t s from the s o i l  Large a n i m a l s - Animals depend on v e g e t a t i o n  f o r food and  are t h u s a f f e c t e d by t r e e removal i n v a r i o u s ways.  causes d i r e c t l o s s o f w i l d l i f e . on p o t e n t i a l f o r a g e h e r b s , and  plants:  J e n s e n , 1971;  Clearcutting rarely  I t i s thought t o have t h r e e major e f f e c t s  a s h i f t i n p l a n t composition favouring  shrubs c h a r a c t e r i s t i c o f e a r l y s u c c e s s i o n a l  i n n u t r i e n t q u a l i t y , and  stages,  an i n c r e a s e i n d r y - m a t t e r p r o d u c t i o n  Taber, 1973;  T e l f e r , 1972).  Taber  i n mature f o r e s t (Brown, 1961;  an  grasses,  increase  ( B a s i l e and  However, t h i s does n o t always  c u r as some s t u d i e s have found t h a t n u t r i e n t q u a l i t y o f forage higher  cover  Gates, 1968).  oc-  i s sometimes  In a recent  review,  (1973) c o n c l u d e d t h a t t h e e f f e c t of c l e a r c u t t i n g c o a s t a l D o u g l a s - f i r  f o r e s t s i s t o cause a slow r i s e i n n u t r i e n t q u a l i t y o f the s u c c e e d i n g veget a t i o n over a p e r i o d o f about t e n y e a r s .  He  a l s o concluded that  although  18  the d i e t a x y q u a l i t y o f f o r a g e r i s e s a f t e r c l e a r c u t t i n g , the e x t e n t o f t h e r i s e and i t s r e l a t i o n t o t i m e , s i t e , and  s i l v i c u l t u r a l treatments are  still  not completely understood. The  i n c r e a s e d q u a l i t y and q u a n t i t y o f f o o d has been f r e q u e n t l y  as e v i d e n c e t h a t c l e a r c u t t i n g b e n e f i t s a n i m a l s et al.,  1974;  R e s l e r , 1974).  (e.g. Hooven 1973a; R e g e l i n  There i s much e v i d e n c e t o suggest t h a t  mals such as d e e r , moose, and e l k , which a r e adapted t o e a r l y s t a g e s do i n f a c t b e n e f i t from c l e a r c u t t i n g Telfer,  1972).  Pengelly  used  (1972) i n d i c a t e d t h a t , w h i l e t h i s may  -cannot be a c c e p t e d as a g e n e r a l i z a t i o n .  successional  (Hooven, 1973a; R e s l e r ,  However, a n a l y s i s o f t h e l i t e r a t u r e by Taber  Taber  ani-  1972;  (1973) and  be t r u e i n some c a s e s , i t (1973) p o i n t e d o u t t h a t the  s e a s o n a l home r a n g e s o f deer and w a p i t i a r e r e l a t i v e l y s m a l l so t h a t a c l e a r c u t i s l i k e l y t o a t t r a c t o n l y t h o s e animals i n whose home range i t lies.  P e n g e l l y (1972) q u e s t i o n e d t h e a c c u r a c y o f p u b l i s h e d d a t a , wonder-  i n g whether more a n i m a l s can be seen i n a c l e a r c u t o n l y because  they are  more r e a d i l y v i s i b l e and whether o r n o t t h e y were t h e same a n i m a l s which f o r m e r l y l i v e d unobserved may  i n the v i c i n i t y .  n o t always be the l i m i t i n g  i s not the l i m i t i n g f a c t o r , o f c o v e r and freedom  He a l s o p o i n t e d out t h a t f o o d  f a c t o r f o r animal p o p u l a t i o n s .  then f o r a g e p r o d u c t i o n may  from harassment.  Where i t  be a t the expense  B e h a v i o u r a l l i m i t s o f an animal  may  t a k e over l o n g b e f o r e f o o d s h o r t a g e s o c c u r and w h i t e - t a i l e d deer, f o r example, f r e q u e n t l y s e l e c t c o v e r i n p r e f e r e n c e t o f o o d .  A l s o , i n c r e a s e d snow  a c c u m u l a t i o n on c l e a r c u t s may  ( P e n g e l l y , 1972).  s t r e s s animals i n winter  P e n g e l l y i s s u p p o r t e d by one o f t h e p r i n c i p a l deer r e s e a r c h e r s who  has  s t a t e d t h a t : " c l e a r c u t t i n g has been c o n s i d e r e d one o f t h e b e s t ways t o improve  deer h a b i t a t  .... Beyond t h e knowledge t h a t c l e a r c u t t i n g  should  19  produce good h a b i t a t ,  very l i t t l e  p r a c t i c e s on d e e r e c o l o g y . t o back up  the  1972;  Much i s assumed, b u t  assumptions."  It i s generally Taber, 1973)  small  more b e n e f i c i a l t o w i l d l i f e  few  influences f a c t s are  of  forest  available  (Crouch, 1969).  considered  that  i s known about the  (Hooven, 1973a; P e n g e l l y ,  c l e a r c u t s , by p r o v i d i n g  than a r e  large  1972;  Resler,  more ecotone,  are  clearcuts.  While t h e r e i s argument about the m e r i t s o f c l e a r c u t t i n g f o r a n i m a l s such as deer and and  e l k , i t appears t h a t a n i m a l s such as martens, f i s h e r s ,  w o l v e r i n e s , which a r e  from c l e a r c u t t i n g  adapted t o mature f o r e s t s , almost always s u f f e r  ( A h l g r e n and  A h l g r e n , 1960;  Grakov, 1972;  Lutz,  1956).  C a r i b o u , which depend t o a c o n s i d e r a b l e  e x t e n t on  food  ) w i l l probably suffer i f c l e a r -  ( L u t z , 1956;  Cowan and  Guiget,  c u t t i n g removes the v a l l e y bottom f o r e s t s and 2.  associated  lichens.  S m a l l mammals - These depend f o r f o o d upon seeds, herbs, or i n -  s e c t s , and litter  tree lichens f o r winter  f o r c o v e r upon the v e g e t a t i o n  layer.  c l o s e t o the  surface  and  C l e a r c u t t i n g a f f e c t s b o t h t h e i r f o o d s u p p l y and  v a r i a b l e ways and  w i l l t h u s have v a r i a b l e e f f e c t s on t h e i r  I n Washington and lagomorphs, and  the  cover i n  populations.  Oregon, p o p u l a t i o n s of r e d backed v o l e s , s q u i r r e l s ,  chipmunks d e c l i n e  after-clearcutting.  a l s o d e c r e a s e i f s l a s h i s l e f t on the c l e a r c u t s , but  Shrew p o p u l a t i o n s  increase  on  older  c l e a r c u t s w i t h dense shrubby v e g e t a t i o n .  However, mountain b e a v e r , deer  mice, and  after clearcutting  several  1973a,b) . Resler, The  t y p e s of v o l e s  Porcupine  1972)  (Resler,  increase  1972)  are a l s o reported  and  t o be  p o c k e t gophers  f a v o u r e d by  r e a s o n s f o r t h e s e changes are not  r e q u i r e m e n t s o f many s m a l l mammal s p e c i e s  (Hooven,  (Barnes,  1971;  clearcutting.  a l l known s i n c e the p a r t i c u l a r a r e unknown and  i t is difficult  20  to evaluate  t h e i r f o r e s t h a b i t a t requirements.  i n c r e a s e d because many p o p u l a t i o n s s h a r p l y from y e a r  t o year  The d i f f i c u l t y i s f u r t h e r  o f s m a l l mammals appear c y c l i c o r v a r y  f o r unknown r e a s o n s  (Hooven, 1973b).  V e r y low temperatures d e c r e a s e t h e o v e r w i n t e r i n g mammals s o t h a t c l e a r c u t t i n g , by exposing  t h e s o i l s u r f a c e t o lower tempera-  t u r e s i n w i n t e r , may, d u r i n g snowless w i n t e r s , some a n i m a l s Hooven  s u r v i v a l rate of small  lower t h e s u r v i v a l r a t e o f  (Hooven, 1973b). (1973b) c o n c l u d e d  change-of s p e c i e s c o m p o s i t i o n  that:  "after c l e a r c u t t i n g , regardless of the  and d e n s i t i e s , t h e s m a l l mammal biomass r e -  mains comparable t o t h a t o f t h e uncut f o r e s t and e x e r t s . t h e same d e t r i m e n t a l e f f e c t upon 3.  regeneration".  B i r d s - Because some b i r d  species evolved  t o l i v e i n mature f o r -  e s t s w h i l e o t h e r s depend on d i s t u r b e d s i t e s and e a r l y s u c c e s s i o n a l c l e a r c u t t i n g a f f e c t s b i r d populations Hagar  stages,  i n d i f f e r e n t ways.  (1960), s t u d y i n g c l e a r c u t s i n D o u g l a s - f i r f o r e s t s i n northwes-  tern C a l i f o r n i a ,  found t h a t l o g g i n g a l t e r e d t h e c o m p o s i t i o n  of the bird  p o p u l a t i o n and l e d t o a temporary d e c l i n e i n o v e r a l l numbers. b e r s were r e g a i n e d w i t h i n a y e a r a f t e r c u t t i n g a l t h o u g h  Former num-  t h e s p e c i e s compo-  s i t i o n was d i f f e r e n t . A f t e r a comprehensive d i s c u s s i o n o f t h e r e l a t i o n s h i p s between b i r d s , f o r e s t s , and f o r e s t management i n A u s t r a l i a , Cowley  (1971) c o n c l u d e d  c l e a r c u t t i n g does n o t d e s t o r y b i r d h a b i t a t b u t s i m p l y  that  changes i t t o t h e  advantage o f some s p e c i e s and t o t h e d i s a d v a n t a g e o f o t h e r s . I n c o n c l u s i o n , a l l t h a t c a n a c c u r a t e l y be s a i d about t h e e f f e c t o f c l e a r c u t t i n g on w i l d l i f e i s t h a t : s p e c i e s o f w i l d l i f e i n some areas  "some c l e a r c u t l o g g i n g b e n e f i t s some some o f t h e t i m e "  ( P e n g e l l y , 1972).  21  (d)  Vegetation  - C l e a r c u t t i n g f a v o u r s the growth of g r a s s e s , h e r b s ,  shrubs by r e v e r t i n g t h e ecosystem back t o an e a r l i e r The  degree o f s i t e d i s t u r b a n c e  stages  the more s e v e r e  (Kimmins, 1972).  gree of d i s t u r b a n c e  and  the u n d i s t u r b e d  forest;  l o g g i n g , however.  types  (1966  and  f a v o u r i n g the  1973)  v e g e t a t i o n t h a n d i d the  growth o f p i o n e e r  due  tree seedlings.  r e d a l d e r i n c o a s t a l B.C.  Isaac,  s p e c i e s which may 1940).  competition  t o the s e v e r e c o m p e t i t i o n  take over a s i t e  composition of  found  s p e c i e s may  great that succession i s delayed  pioneer  de-  species composition  some p r e - l o g g i n g s p e c i e s c o u l d s t i l l be  Salmonberry and  earlier  found t h a t the  s l a s h d i s p o s a l had more i n f l u e n c e on t h e  On r i c h e r s i t e s ,  is  t o which t h e ecosystem i s  of disturbance  Thus, Dyrness  of t h e subsequent p i o n e e r  stage.  caused by c l e a r c u t t i n g o p e r a t i o n s  l i k e l y t o determine the p a r t i c u l a r s e r a i stage reverted, with  successional  and  after  be  so  faced  by  a r e examples of  ( F r a n k l i n and D e B e l l ,  1973;  When t h e t r e e s p e c i e s d e s i r e d by f o r e s t e r s e x p e r i e n c e s  and  cannot grow s u c c e s s f u l l y , then the y i e l d o f t h e  such  site,  from t h e f o r e s t e r ' s p o i n t o f view, i s lowered. The  f o l l o w i n g r e v i e w of the e f f e c t s of c l e a r c u t t i n g on t r e e s w i l l  l i m i t e d t o the t r e e s o f the lower e l e v a t i o n f o r e s t s o f south c o a s t a l  be  B.C.  These f o r e s t s l i e i n K r a j i n a ' s C o a s t a l D o u g l a s - f i r and C o a s t a l Western Heml o c k b i o g e o c l i m a t i c zones of B.C. and Brooke, 1970)  ( K r a j i n a , 1959,  1969;  Krajina  l e s s e r amounts o f grand f i r , w e s t e r n  white p i n e , r e d a l d e r , b i g l e a f maple, and  other deciduous s p e c i e s .  and w e s t e r n hemlock are t h e most important  the o n l y two  and  and c o n t a i n m a i n l y S i t k a s p r u c e , D o u g l a s - f i r , western  hemlock, and western r e d c e d a r , w i t h  fir  1965  w h i c h w i l l be c o n s i d e r e d  Douglas-  commercial s p e c i e s and  in detail.  are  22  1.  Douglas-fir  and mesic s o i l s .  - C o a s t a l D o u g l a s - f i r r e q u i r e s moderate temperatures  I t i s intermediate  l i g h t t h a n most o f i t s a s s o c i a t e s . new  seedlings  grows b e s t  i n shade t o l e r a n c e b u t demands more I t prefers mineral  b e n e f i t from l i g h t shade.  in full  sunlight  (Fowells,  soil  seedbeds  and  Once e s t a b l i s h e d , however, i t  1965;  W i l l i a m s o n , 1973).  I n t h e x e r i c t o mesic s i t e s of the C o a s t a l D o u g l a s - f i r zone and  the  x e r i c s i t e s o f the C o a s t a l Western Hemlock zone, D o u g l a s - f i r i s r a t h e r tolerant  ( K r a j i n a , 1969)  so t h a t c l e a r c u t t i n g , p a r t i c u l a r l y f o l l o w e d  s l a s h d i s p o s a l , would p r o b a b l y not p r o v i d e Douglas-fir regeneration.  F a i l u r e of D o u g l a s - f i r regeneration  o f t h e more s e v e r e s i t e s has 1973;  Isaac,  cutting  1971;  1963)  and  Gilmour, 1970;  ( F r a n k l i n , 1963;  Starker,  t o Washington and  1970;  for  on  clearcuts  F r a n k l i n and  stated that:  Green, 1968;  Duffield  F r a n k l i n and  Smith  DeBell,  (1971), w i t h  complete exposure i s u s u a l l y d e t r i m e n t a l  "In most i n s t a n c e s t h e  He  considered  to regeneration  of  opti-  t h a t shelterwood c u t t i n g , r a t h e r than c l e a r -  l o g i c a l optimum f o r D o u g l a s - f i r on each s i t e .  However, p l a n t i n g  can o f t e n overcome the d i s a d v a n t a g e s caused t o D o u g l a s - f i r clearcutting.  I n the U.S.,  (Williamson,  s h e l t e r w o o d c u t t i n g appears t o be  1973).  eco-  seedlings  regeneration  slowly r e p l a c i n g c l e a r c u t t i n g of D o u g l a s - f i r , f o r s i l v i c u l t u r a l among o t h e r s  shade....  Douglas-fir  c u t t i n g , most c l o s e l y i m i t a t e d the n a t u r a l p r o c e s s e s l e a d i n g t o the  by  1973;  reference  environment f o r young D o u g l a s - f i r s i s found u n d e r n e a t h p a r t i a l  on many s i t e s . "  DeBell,  s e v e r a l workers have advocated  ( F r a n k l i n , 1963;  W y l i e , 1960).  Oregon, has  by  a l t h o u g h most f o r e s t e r s p r e s c r i b e c l e a r -  Smith, 1962)  of s h e l t e r w o o d c u t t i n g s  Garman, 1955;  mum  Isaac,  been noted  f o r o l d growth D o u g l a s - f i r f o r e s t s ( D e l l and  and D a v i s , the use  1938;  the optimum c o n d i t i o n s  shade  very reasons  23  In K r a j i n a ' s  Coastal  t h e r e i s some p l a n t i n g  Douglas-fir  and  Coastal  of S i t k a s p r u c e i n the  low  Western Hemlock zones, e l e v a t i o n wetter  and w e s t e r n hemlock i n the h i g h e r e l e v a t i o n s i t e s , but o f the  f o r e s t s i n t h e s e zones i s managed f o r  Douglas-fir for  a few  i s a pioneer species  with r i c h s o i l s derived  more p e r s i s t e n t  ( K r a j i n a , 1969).  s c r i b e d c u t t i n g method and  the g r e a t  on a l l of t h e m o i s t s i t e s  the c l e a r c u t a r e a i n due  the wetter, but  except  from b a s a l t o r d i o r i t e , on which i t i s C l e a r c u t t i n g i s v i r t u a l l y the  only  u s u a l l y succeeds i n promoting D o u g l a s - f i r  Dombois, I960; Osborn, 1968; On  majority  Douglas-fir.  a t the'expense o f i t s more shade t o l e r a n t t r e e c o m p e t i t o r s , b u t restock  course  ( F r a n k l i n and  DeBell,  a c o m p e t i t i v e advantage  fir  initially.  1973;  ( K r a j i n a , 1969), c l e a r c u t t i n g may  Western hemlock, however, may  eventually  favour Douglas-  t a k e over such  s l a s h t r e a t m e n t w i l l be  Clearcutting  lost.  w e s t e r n hemlock, as d i s c u s s e d  ment o f Botany, U n i v e r s i t y  o f B.C.:  With r e g a r d t o D o u g l a s - f i r that:  i s not  dominate  in  (V.J. K r a j i n a ,  retarded Depart-  P e r s o n a l communication).  regeneration,  i t has  "Almost a l l c l e a r c u t t i n g and  ods,  excepting only true  able  f o r r e g e n e r a t i o n of f o r e s t s o f D o u g l a s - f i r  been s t a t e d  (Franklin  p a r t i a l c u t t i n g meth-  s e l e c t i o n t e c h n i q u e s , have p r o v e d b i o l o g i c a l l y ....  On  the m a j o r i t y  f o r e s t s i t e s , t h e s e l a r g e c l e a r c u t t i n g s have been r e m a r k a b l y  of Douglas-fir,  or  always b e n e f i c i a l t o  below, so t h a t i t s growth might be  some time a l t h o u g h i t w i l l e v e n t u a l l y  i n no way  Mueller-  W i l l i a m s o n , 1973).  investment i n p l a n t i n g D o u g l a s - f i r  They a r e  initially  these u s u a l l y  s i t e s w i t h t h e r e s u l t t h a t any  and D e B e l l , 1973)  pre-  n u t r i t i o n a l l y p o o r e r s i t e s where w e s t e r n hemlock  has  for  sites  suit-  of  successful.  b i o l o g i c a l l y e s s e n t i a l f o r r e g e n e r a t i n g even-aged stands  however."  24  2.  Western hemlock - Western hemlock i s becoming an i n c r e a s i n g l y  i m p o r t a n t commercial  species.  I t i s v e r y shade t o l e r a n t and r e g e n e r a t e s  b o t h on m i n e r a l s o i l and o r g a n i c seedbeds Harmon, 1963).  It is difficult  ( B e r n s t e n , 1955; F o w e l l s , 1965;  t o e s t a b l i s h a r t i f i c i a l l y and r e g e n e r a -  t i o n from c l e a r c u t t i n g i s not always s u c c e s s f u l , t h i s b e i n g a t t r i b u t e d t o d e s i c c a t i o n i n summer o r f r o s t h e a v i n g i n w i n t e r Soos and W a l t e r s , 1963).  Partial  (Osborn,  1968; Ruth, 1968;  shading o f s e e d l i n g s i s c o n s i d e r e d de-  s i r a b l e s i n c e s u n - s c o r c h i n g may o c c u r under s e v e r e c o n d i t i o n s ( F o w e l l s , 1965;  Harmon, 1963; Soos and W a l t e r s , 1963).  Keller  (1973) found  western hemlock advanced r e g e n e r a t i o n i n f o r e s t s i s adapted i n t e n s i t i e s and exposure  that  t o low l i g h t  o f t h e s e t r e e s t o s u n l i g h t a s , f o r example, by  c l e a r c u t t i n g , o f t e n causes i n j u r y o r d e a t h from s c o r c h i n g . Its  low demand f o r n u t r i e n t s and i t s a b i l i t y  hemlock s u i t a b l e f o r many forms o f management.  t o t o l e r a t e shade r e n d e r  In f a c t , i t has been s u c -  c e s s f u l l y r e g e n e r a t e d by a l l c u t t i n g methods ( F r a n k l i n and D e B e l l , 1973; Ruth and H a r r i s , 1973). tivity or  t o exposure,  Due t o i t s s h a l l o w - r o o t e d n a t u r e and i t s s e n s i -  i t b e n e f i t s from m i x t u r e s w i t h D o u g l a s - f i r , S i t k a  a m a b i l i s f i r (Anderson,  o f t e n been advocated  spruce,  1956, K r a j i n a , 1954) and s h e l t e r w o o d c u t t i n g has  ( F o w e l l s , 1965; Herman, 1962; Osborn, 1967; Ruth and  H a r r i s , 1973; W i l l i a m s o n , 1966), i n some c a s e s w i t h hemlock o c c u p y i n g t h e lower s t o r y and D o u g l a s - f i r , a m a b i l i s f i r , o r S i t k a spruce t h e upper s t o r y i n two s t o r y mixed f o r e s t s  (Osborn,  1968; W y l i e ,  1960).  I t i s commonly i n f e c t e d w i t h dwarf m i s t l e t o e c u t t i n g system i s clearcutting  i n which case the o n l y  which appears t o p r e v e n t s e r i o u s a t t a c k s on r e g e n e r a t i o n (Buckland and M a r p l e s , 1952; -Ruth and H a r r i s ,  1973).  It  i s a l s o v e r y s u s c e p t i b l e t o l o g g i n g i n j u r y w i t h decay s e t t i n g i n r a p i d l y , which f a v o u r s c l e a r c u t t i n g oyer p a r t i a l c u t t i n g methods (Shea,  1960).  25  The s i l v i c a l  c h a r a c t e r i s t i c s and r e g e n e r a t i o n r e q u i r e m e n t s o f b o t h  D o u g l a s - f i r and western hemlock suggest u s i n g a c u t t i n g method which p r o duces even-aged s t a n d s , i . e . c l e a r c u t t i n g , s e e d - t r e e , o r s h e l t e r w o o d c u t t i n g methods.  Any o f t h e s e methods may  be used depending on s i t e  and/or  requirements.  I n summary, from a s i l v i c u l t u r a l s t a n d p o i n t , e x c l u d i n g e c -  onomic arguments, c l e a r c u t t i n g o f t e n appears t o be the b e s t h a r v e s t i n g method, b u t n o t always. (3)  E f f e c t s on streams and a q u a t i c  ecosystems  (a)  Streamflow - By r e d u c i n g e v a p o t r a n s p i r a t i o n and canopy i n t e r c e p t i o n  l o s s e s , t r e e removal u s u a l l y causes i n c r e a s e d s t r e a m f l o w and may  also  de-  c r e a s e the r e s p o n s e time o f a stream t o p r e c i p i t a t i o n , the e f f e c t s b e i n g most pronounced mour, 1971;  d u r i n g the growing season  H e w l e t t and H i b b e r t , 1967;  1973;  Hornbeck e t al. , 1970;  1973;  Rothacher, 1971;  (Anderson and Hobba, 1959; G i l -  H e w l e t t and Melvey,  L u l l and R e i n h a r t , 1972;  Sopper and Lynch, .1970).  1970;  Hornbeck,  Nakano, 1967;  Patric,  H i b b e r t (1967), summariz-  i n g the r e s u l t s o f many watershed c u t t i n g e x p e r i m e n t s , found t h a t the r e sponse o f s t r e a m f l o w t o c l e a r c u t t i n g v a r i e d g r e a t l y and was dictable.  u s u a l l y unpre-  However, f o r humid r e g i o n s , the i n c r e a s e i n s t r e a m f l o w a f t e r  c l e a r c u t t i n g was  p r o p o r t i o n a l t o t h e p e r c e n t a g e o f t h e watershed a r e a c u t  w i t h an a p p a r e n t upper l i m i t o f y i e l d i n c r e a s e about 4.5 mm each p e r c e n t r e d u c t i o n i n f o r e s t c o v e r . s t r e a m f l o w r e s p o n s e t o c l e a r c u t t i n g was  per year f o r  The s e a s o n a l d i s t r i b u t i o n o f variable.  The r e s p o n s e i n stream-  f l o w appeared almost immediately or some time l a t e r , depending on soils,  climate,  topography, and o t h e r f a c t o r s .  Snowmelt i s a l s o a f f e c t e d by c l e a r c u t t i n g .  I n g e n e r a l , the removal  of v e g e t a t i o n causes an i n c r e a s e i n the snowpack f o l l o w e d by more r a p i d  26  melting i n the s p r i n g  (Anderson, 1967;  Swank, 1970;  1958;  acher,  Goodell,  1965).  T h i s may  Hornbeck, 1973;  be m o d i f i e d by  and o r i e n t a t i o n o f the c u t o v e r L u l l and R e i n h a r t , son  Bay,  1972;  L u l l and  aspect  Increased spawning b e d s .  and t h e  extent  (Anderson,  Anderson and  1971;  Glea-  i s v a r i a b l e although  the  i t ap-  i n t h e e a r l y p a r t of  part  ( L u l l and  the  Reinhart,  1972).  be d e t r i m e n t a l t o f i s h t h r o u g h s c o u r i n g  However, i n c r e a s e d low f l o w s i n summer may  f i s h by i n c r e a s i n g the  Roth-  i n which s l a s h had been removed by  i n c r e a s e peak f l o w s  f l o o d f l o w s may  and  1972;  solar r a d i a t i o n , slash increased  snowmelt season b u t r e d u c e them i n the l a t t e r  to  (Haupt, 1972)  e f f e c t o f snowmelt on peak flows  p e a r s t h a t c l e a r c u t t i n g may  Berndt  Reinhart,  S a t t e r l u n d and Haupt, 1972)-  m e l t i n g r a t e o f snow compared t o areas The  B e r n d t , 1965;  a r e a s , as w e l l as by c l i m a t e  (1960) found t h a t , by a b s o r b i n g  burning.  1958;  be  space a v a i l a b l e t o them i n streams  of  beneficial (Chapman,  1962). (b)  Sediment l o a d - I n c r e a s e d  gether w i t h  l o s s o f p r o t e c t i v e v e g e t a t i v e c o v e r , may  s o i l from t e r r e s t r i a l bed  flows o f water from l a n d t o streams, t o -  and bank e r o s i o n .  t o a q u a t i c ecosystems, as w e l l as a c c e l e r a t i n g streamT h i s i n c r e a s e s sediment l o a d s i n streams, as  been f r e q u e n t l y o b s e r v e d a f t e r  logging  Burns, 1972;  1972;  1962;  Megahan and K i d d ,  Swanston, 1971).  The  (Anderson, 1954;  Narver, 1972;  Anderson,  Reinhart  break-up o f l o g g i n g - c a u s e d  subsequent f l o o d s u r g e s i s a n o t h e r major s o u r c e Froehlich,  i n c r e a s e removal of  1971;  Eschner,  d e b r i s jams w i t h  o f sediment  (Curry,  1973;  1971).  I t appears t h a t most o f the  stream sediment a s s o c i a t e d w i t h  c u t t i n g o r i g i n a t e s from r o a d c o n s t r u c t i o n (Anderson, 1954; Brown and  and  has  K r y g i e r , 1971;  Dils,  1957;  F r e d r i k s e n , 1965;  clear-  Anderson,  Fredriksen,  1971; 1970;  27  Megahan, 1972; Megahan and Kidd, 1972; Packer, 1967; Reinhart and  Eschner,  1962; Swanston, 1971b). In c o a s t a l Oregon, Brown and Krygier (1971) found that c l e a r c u t t i n g produced l i t t l e or no change i n sediment concentrations i n streams whereas road construction and slashburning both produced s i g n i f i cant increases.  Well c o n t r o l l e d clearcutting may  cause no s i g n i f i c a n t i n -  crease i n stream sediment concentrations (Jeffrey and Goodell, 1970; Leaf, 1966; Reinhart and Eschner, 1962).  Thus, stream sediment load i s c l o s e l y  correlated with the q u a l i t y of timber harvesting p r a c t i c e s and roads and ging skid t r a i l s are the main sources of sediment.  log-  The degree of stream  sedimentation depends on the type of logging but tends to increase with increasing slopes, and the duration of sedimentation depends on the rate of revegetation, other factors being equal (Dyrness, 1967; Rice et al. , 1972) .  Cordone and K e l l e y (1961), Chapman (1962), Gibbons and Salo (1973), and P h i l l i p s  (1971) have reviewed the e f f e c t s of sediment on aquatic l i f e .  High sediment l e v e l s may have detrimental e f f e c t s on adult f i s h ,  develop-  ment of eggs and a l e v i n s , production of aquatic plants and f i s h food organisms.  High t u r b i d i t y l e v e l s may:  prevent adults from spawning or cause  death where concentrations are high and exposure prolonged; destroy spawning beds; smother eggs reducing t h e i r supply of oxygen and i n t e r f e r i n g with the removal of p o t e n t i a l l y . t o x i c metabolites; prevent f r y from emerging i n t o the stream; decrease the abundance of f i s h food organisms; and i n duce changes i n the species composition of f i s h communities. cently been shown (Bustard, 1973) that f i s h i n c o a s t a l B.C. f e r clean gravel to sedimented gravel streambeds.  I t has r e streams pre-  28  These e f f e c t s may  be p a r t i c u l a r l y s i g n i f i c a n t s i n c e many o f t h e  small  streams f l o w i n g t h r o u g h f o r e s t e d areas c o n s t i t u t e the spawning a r e a s f o r fish. (c)  Logging  although  d e b r i s - C l e a r c u t t i n g n e a r l y always d e p o s i t s d e b r i s i n streams  t h i s can be m i n i m i z e d by t a k i n g simple p r e c a u t i o n s  Rothwell,  1971;  U.S.  Department of t h e I n t e r i o r , 1970).  (Burwell,  Debris  1971;  deposited  i n f i s h b e a r i n g streams can i n t e r f e r e w i t h m i g r a t i o n o f a d u l t s and  juven-  i l e f i s h , t e m p o r a r i l y reduce p o o l h a b i t a t , reduce oxygen c o n c e n t r a t i o n s i n s u r f a c e and (Narver,  i n t r a g r a v e l water, and can i m p a i r t h e q u a l i t y of spawning g r a v e l  1971).  peak f l o w s may  I n a d d i t i o n , d e b r i s l e f t i n stream channels  cause s c o u r i n g and d i v e r s i o n , i n c r e a s i n g stream  and d e c r e a s i n g f i s h p o p u l a t i o n s dl.  (1971) found  allowed  during spring  ( E l s e r , 1968;  N a r v e r , 1971).  sedimentation Servizi  et  t h a t h i g h b a r k c o n c e n t r a t i o n s i n streams i n s o u t h e r n  B.C.  abundant growth o f a f i l a m e n t o u s b a c t e r i a on f r e s h l y d e c a y i n g  T h i s b a c t e r i a caused s e v e r e m o r t a l i t y o f f i s h embryos and  bark.  a l e v i n s due  to  suffocation. On t h e o t h e r hand, d e b r i s accumulations f o r coho and  t r o u t , and may  the a c c u m u l a t i o n s 1973;  a r e n o t f l u s h e d away by f r e s h e t s  By c o v e r i n g a stream, d e b r i s may  r i s e s i n stream temperatures d u r i n g summer (d)  p r o v i d e good w i n t e r  cover  thus provide favourable f i s h h a b i t a t , p r o v i d i n g  are s t a b l e and  Hartman, 1968).  may  Stream temperature — The  (Levno and  prevent  (Bustard,  excessive  Rothacher, 1969).  removal o f v e g e t a t i o n , p a r t i c u l a r l y  stream-  bank v e g e t a t i o n , from watersheds u s u a l l y causes a r i s e i n stream temperat u r e d u r i n g t h e summer 1971;  Burns, 1972;  Levno and  (Brown, 1969;  Brown and  Gray and E d g i n g t o n ,  Rothacher, 1967;  1969;  K r y g i e r , 1970;  Greene, 1950,  Meehan et dl. , 1969;  Brown et  Hall,  N a r v e r , 1972;  dl.,  1967;  Patton,  1973;  29  S w i f t and Baker, 1973;  S w i f t and Messer,  c r e a s e d u r i n g w i n t e r (Greene, 1950).  1971;  Titcomb,  1926)  and a de-  The magnitude o f t h e temperature i n -  c r e a s e depends on t h e s i z e o f the stream, b e i n g g r e a t e r f o r s m a l l streams, other f a c t o r s being equal. air  Downstream e f f e c t s a r e complex, depending  on  t e m p e r a t u r e s , stream c o v e r , and temperature and s i z e o f t r i b u t a r y  streams  (Brown et al.,  1971;  and Rothacher,. 1967).  Gray and E d g i n g t o n , 1969;  Greene,  The r e t e n t i o n o f s t r e a m s i d e v e g e t a t i o n , even  on s m a l l streams, tends t o m i n i m i z e any temperature changes cutting 1972;  (Brown, 1969;  L a n t z , 1971;  1950;  Brown and K r y g i e r , 1970;  R e i n h a r t et al.,  1963;  shrubs  following  Brown et al.,  S w i f t and Baker,  Levno  1971;  clear-  Burns,  1973).  Chapman (1962) and L a n t z (1971a) have reviewed the i n f l u e n c e s o f ter  temperature on f i s h .  I n c r e a s e d o r d e c r e a s e d temperatures d u r i n g the  e a r l y s t a g e s o f embryonic teristics  of f i s h .  wa-  development  can m o d i f y s e v e r a l p h y s i c a l c h a r a c -  I n c r e a s e d temperatures may  cause gaseous  nitrogen to  come o u t o f s o l u t i o n , s u p e r s a t u r a t i n g t h e water w i t h n i t r o g e n and c a u s i n g symptoms i n f i s h s i m i l a r t o the "bends"  i n man.  I n c r e a s e d temperature  also  i n c r e a s e s t h e v i r u l e n c e o f many f i s h d i s e a s e s , i n c r e a s e s t h e t o x i c i t y o f many c h e m i c a l s t o f i s h , and enhances  lowers the amount o f oxygen d i s s o l v e d i n streams,  t h e decay o f o r g a n i c m a t e r i a l p r e s e n t , f u r t h e r d e c r e a s i n g d i s -  s o l v e d oxygen l e v e l s .  B e h a v i o u r a l and p h y s i o l o g i c a l changes  o c c u r w h i c h p r e v e n t them from m i g r a t i n g i n t o t h e i r spawning c r e a s e d w i n t e r temperatures may or w i n t e r - s p a w n i n g  fish,  i n fish rivers.  De-  extend the i n c u b a t i o n p e r i o d f o r autumn-  i n c r e a s i n g t h e l i k e l i h o o d o f exposure o f embryos  to  s e v e r e f l o o d or u n f a v o u r a b l e i n t r a g r a v e l water c o n d i t i o n s .  of  f r y emergence beyond  and d e c r e a s e i n i t i a l  may  normal p e r i o d s may  growth.  Extension  increase losses to predators  30  A l t h o u g h t h e e f f e c t s o f c l e a r c u t t i n g were not s e p a r a t e d from t h o s e of  s l a s h b u r n i n g , H a l l and L a n t z (1969) i n Oregon found t h a t  clearcutting  and s l a s h b u r n i n g a s m a l l watershed s i g n i f i c a n t l y r e d u c e d the number o f r e s i d e n t f i s h i n the stream, b u t had l i t t l e salmon.  On Vancouver  initial  e f f e c t on numbers o f coho  I s l a n d , s t e e l h e a d numbers have been found t o be  g r e a t e r i n s e c t i o n s o f a stream f l o w i n g t h r o u g h f o r e s t r a t h e r t h a n i n s e c t i o n s f l o w i n g through c l e a r c u t s  (Narver, 1972).  I n c r e a s e d summer stream temperatures can be b e n e f i c i a l t o f i s h i n some instances.  C o l d streams, shaded by dense f o r e s t c a n o p i e s , a r e n o t optimum  trout habitat a t u r e s may  (White and B r y n i l d s o n , 1967).  speed up the l a t e s t a g e s o f embryonic  e a r l i e r emergence the  Thus, i n c r e a s e d stream temper-  (Narver, 1972).  development,  I n c r e a s e d temperatures may  resulting i n also increase  p r o d u c t i o n o f b a c t e r i a , a l g a e , and t h e i n s e c t s upon which f i s h  (Burns, 1972;  Krammes and Burns, 1973).  F i s h growth, however, i s r a t h e r  c o m p l i c a t e d , depending on t h e b a l a n c e between f o o d p r o d u c t i o n and mental c o n d i t i o n s .  feed  environ-  F o r example, i n c r e a s e d stream temperatures w i l l d e c r e a s e  f i s h growth i f f o o d p r o d u c t i o n remains t h e same o r i s lowered  ( B r e t t et  at.,  1969). (e)  I n o r g a n i c n u t r i e n t c h e m i c a l s - When c l e a r c u t t i n g i n c r e a s e s t h e f l o w o f  chemicals through the s o i l ,  as d i s c u s s e d above, i n c r e a s e d c h e m i c a l c o n c e n t r a -  t i o n s i n streams can be e x p e c t e d . ticularly Ce.g.  T h i s has now  been w e l l documented, p a r -  from t h e numerous p a p e r s d e s c r i b i n g experiments a t Hubbard  B o r m a n n e t al,,  P i e r c e et at.,  1968, Hornbeck et at.,  1973;  L i k e n s et at.,  1970;  1972), and b r i e f r e v i e w s o f t h i s f i e l d have r e c e n t l y  (Gibbons and S a l o , 1973;  Rothacher, 1970;  Tarrant,  1970).  Brook  appeared  31  Fredriksen  (1971), i n Oregon, found  increase i n chemical  c o n c e n t r a t i o n s i n streamwater whereas s l a s h b u r n i n g  caused a much g r e a t e r i n c r e a s e . 1973)  found  that clearcutting l e d to a s l i g h t  i n c r e a s e d potassium  Another study i n Oregon and  (Brown et  n i t r a t e c o n c e n t r a t i o n s and  at.,  unchanged  phosphorus c o n c e n t r a t i o n s i n a stream f o l l o w i n g c l e a r c u t t i n g and  burning,  b u t the e f f e c t s o f c l e a r c u t t i n g were not s e p a r a t e d  burning.  I n the same study another one  watershed which was  of i t s t h r e e c l e a r c u t u n i t s s l a s h b u r n e d ,  from t h o s e of  25% p a t c h c u t and had  showed no change i n concen-  t r a t i o n s o r y i e l d s o f n i t r a t e , potassium, o r phosphorus a f t e r The  Hubbard Brook workers  have found  n u t r i e n t chemical  ( L i k e n s et at.,  1970;  logging.  P i e r c e et at.,  t o extend  f o r a t l e a s t three years f o l l o w i n g  c l e a r c u t t i n g , d e s p i t e v e g e t a t i o n regrowth. s i m i l a r d e l a y s i n peak c o n c e n t r a t i o n s and  F r e d r i k s e n et at.  y i e l d s and  (1973)  t i o n s i n streams f o l l o w i n g c l e a r c u t t i n g may  in  Oregon, t o be s t i l l  of  clearcutting.  i n the H.J.  not p e r s i s t f o r more than  Andrews e x p e r i m e n t a l  above p r e - l o g g i n g l e v e l s s i x y e a r s a f t e r  Hubbard Brook workers  ( P i e r c e et at. , 1972)  made d u r i n g t h e summer months had in  concentra-  However, t h e i r d a t a show streamwater n i t r a t e c o n c e n t r a t i o n s ,  l o w i n g c l e a r c u t t i n g and b u r n i n g  greater t o t a l  found  c o n s i d e r e d t h a t where  r e v e g e t a t i o n i s r a p i d , as on t h e Oregon c o a s t , i n c r e a s e d c h e m i c a l  The  1972)  c o n c e n t r a t i o n s and y i e l d s t o be g r e a t e s t t h e  second y e a r a f t e r c u t t i n g and  years.  only  found  seven fol-  forest completion  that clearcuts  loss of chemical n u t r i e n t s  streams than d i d autumn c l e a r c u t t i n g s . T h i s was  a t t r i b u t e d t o the  ex-  tended exposure o f the s i t e f o l l o w i n g a summer c l e a r c u t t i n g s i n c e , r e g a r d l e s s o f c u t t i n g time, v e g e t a t i o n d i d not become e s t a b l i s h e d u n t i l t h e lowing growing s e a s o n .  Another study  a t Hubbard Brook  (Hornbeck et  folat.  s  32  1973)  compared streamwater chemical concentrations and y i e l d s i n a stream  from a clearcut watershed to another which had one-third of i t s area c l e a r cut i n s t r i p s .  Both cutting treatments increased chemical concentrations  i n streamwater but the s t r i p cutting d i d t h i s to a lesser extent. The Hubbard Brook workers have generally shown that, f o r the ecosystems they studied, c l e a r c u t t i n g caused decreases i n pH, and increases i n the concentrations of a l l the major ions except ammonium, sulphate, and bicarbonate i o n s .  N i t r a t e increases were the most spectacular due to the  enhanced a c t i v i t y of n i t r i f y i n g bacteria, as discussed above.  Sulphate  concentrations decreased a f t e r cutting, which has been a t t r i b u t e d (1) an increase i n the volume of water discharged, and  (2)  to  to either the elim-  i n a t i o n of sulphate producing sources within the system due to the t o x i c i t y of high n i t r a t e concentrations to sulphur-oxidizing b a c t e r i a , and/or i n creased reduction of sulphate to sulphide under the more anaerobic condit i o n s p r e v a i l i n g i n the s o i l a f t e r cutting (Hornbeck et at., 1973; et at., 1970).  Likens  I t was a l s o found that n i t r a t e concentrations i n stream-  water a f t e r c l e a r c u t t i n g peaked e a r l i e r i n autumn.  C l e a r c u t t i n g , followed  by burning i n Oregon, increased streamwater n i t r a t e concentrations but to a lesser extent than at Hubbard Brook and caused no apparent change i n the seasonal d i s t r i b u t i o n of streamwater n i t r a t e concentrations (Brown et at.,  1973; Fredriksen, .1971). P a r t i a l c l e a r c u t t i n g , i n s t r i p s at Hubbard Brook (Hornbeck et at., 1973), or patches i n Oregon (Brown et at., 1973) i n Oregon (Fredriksen et at., 1973)  as well as shelterwood  cutting  have been shown to cause smaller changes  i n streamwater chemistry than extensive c l e a r c u t t i n g .  This i s p a r t l y due  to the f a c t that smaller proportions of the watersheds were affected by  33  c u t t i n g and p a r t l y because the a r e a t h a t was the e f f e c t s of the n u t r i e n t s leached  l o g g i n g on s t r e a m s . out o f the  from e x c e s s h e a t by  l e f t unlogged could  reduce  Thus, p l a n t r o o t s c o u l d t a k e  logged areas,  and p r o t e c t i o n o f the c u t a r e a s  a s u r r o u n d i n g f o r e s t c o u l d r e d u c e the r a t e o f decom-  p o s i t i o n o f s l a s h and hence the a v a i l a b i l i t y o f n u t r i e n t s on the areas  (Hornbeck et al.,  potassium concentrations  by v i g o r o u s a high and  (1973) found no  change i n  o f chemicals i n a stream f o l l o w i n g c l e a r c u t t i n g of a l l aswatershed.  He  considered  that  this  t o s l o w decay r a t e s caused by a c o o l c l i m a t e , n u t r i e n t uptake regeneration,  s h a d i n g o f t h e s o i l s u r f a c e by t h e  s o i l c a t i o n exchange c a p a c i t y , a b s o r p t i o n i t s organisms, o r the low r e l i e f  A s t u d y o f c l e a r c u t and t h e e a s t e r n U.S.,  o f the  regeneration,  o f excess n u t r i e n t s by  h i g h l y d i s t u r b e d watersheds a t Coweeta, i n  found t h a t n u t r i e n t f l u x e s i n streams f l o w i n g  watershed nearby  stream c h e m i s t r y was  the  watershed.  from h i g h l y  d i s t u r b e d watersheds were n o t v e r y d i f f e r e n t t o the f l u x e s from an turbed  and  (Wiklander, 1974).  studies, Verry  i n a mixed a s p e n - b l a c k s p r u c e bog  might be due  bog  a l s o been found t o i n c r e a s e n i t r o g e n  i n streamwater  I n c o n t r a s t t o the p r e v i o u s  pen  cutover  1973).  I n Sweden, c l e a r c u t t i n g has  concentrations  up  (Johnson and  Swank, 1971  and  1973).  undis-  However,  o n l y s t u d i e d some t h i r t y y e a r s a f t e r t h e v a r i o u s  ments began so the i n i t i a l e f f e c t s o f the c u t t i n g on  the treat-  stream c h e m i s t r y  are  unknown. Ions r e a d i l y a t t a c h themselves t o f i n e sediment p a r t i c l e s so t h a t l o s s o f s o i l from an a r e a may and McDowell, 1970) .  i n c r e a s e c h e m i c a l l o s s e s from t h a t a r e a  A l t h o u g h Kennedy  (Grissinger  (1965) found t h a t the r a t i o o f  s o r b e d c a t i o n s t o those i n s o l u t i o n can be g r e a t e r t h a n one,  watershed  ad-  34  s t u d i e s at. Coweeta have found t h a t o v e r 98% o f t h e amounts o f each o f c a l cium, magnesium, p o t a s s i u m , and sodium i n streams was (Johnson  and Swank, 1971 and  i n d i s s o l v e d form  1973).  Streams a l s o remove c h e m i c a l s which a r e i n immobile ment p a r t i c l e s .  A t Hubbard  Brook i t was  forms w i t h i n  sedi-  found t h a t s o l u t i o n l o s s e s , how-  e v e r , a c c o u n t e d f o r more t h a n 94% o f t h e a n n u a l l o s s e s i n streams o f a l l t h e common elements e x c e p t p o t a s s i u m and s i l i c o n , where t h e f i g u r e was 80%, and aluminium, where t h e f i g u r e was r i k s e n et al.  72%  (Bormann et al.,  about  1969).  Fred-  (1973) c o n s i d e r e d t h a t c h e m i c a l l o s s e s v i a s o i l e r o s i o n a r e  i m p o r t a n t i n watersheds w i t h s t e e p s l o p e s and F r e d r i k s e n  (1971) found t h a t  more t h a n h a l f the amount o f n i t r o g e n l o s t from a watershed f o l l o w i n g  clear-  c u t t i n g and s l a s h b u r n i n g was  Crisp  o r g a n i c n i t r o g e n c o n t a i n e d i n sediment.  (1966) s t u d i e d n u t r i e n t l o s s e s i n d i s s o l v e d and p a r t i c u l a t e forms i n a stream d r a i n i n g a p e a t y watershed u s e d f o r sheep g r a z i n g .  From h i s d a t a  i t can be c a l c u l a t e d t h a t l o s s e s i n d i s s o l v e d form a c c o u n t e d f o r 99% o f t h e sodium,  92% o f t h e c a l c i u m , 81% o f t h e p o t a s s i u m , 47% o f the phosphorus,  and 17% o f t h e n i t r o g e n l o s t a n n u a l l y .  These s t u d i e s s u g g e s t t h a t  o f t h e n o n - m e t a l l i c n u t r i e n t elements from a watershed may  be  i f t h e stream f l o w i n g from the watershed c o n t a i n s much o r g a n i c  loss  significant sediment.  When sedimented stream water reaches l a k e s o r a r e a s o f r e l a t i v e l y water, t h e sediment w i l l be d e p o s i t e d . i n sediment p a r t i c l e s may  eutrophication.  f o l l o w i n g c l e a r c u t t i n g may tic  The c h e m i c a l s bound t o o r c o n t a i n e d  e i t h e r remain i m m o b i l i z e d i n t h e s e d e p o s i t s o r  be r e l e a s e d t o t h e s u r r o u n d i n g w a t e r . c h e m i c a l s , c a n enhance  still  T h i s , combined  with the d i s s o l v e d  A s m a l l f l u x o f c h e m i c a l s i n streams  be h i g h l y b e n e f i c i a l t o t h e p r o d u c t i v i t y o f aqua-  ecosystems, e s p e c i a l l y o l i g o t r o p h i c ones, b u t l a r g e f l u x e s moving  into  35  r i c h e r systems may lead to vigorous  growth of algae and a l g a l blooms,  t h i s growth being enhanced by increased stream temperatures following c l e a r cutting (Likens et al., 1970; Pierce et al., 1972; Werner, 1973).  Hansmann  and Phinney (1973) observed changes i n the m i c r o f l o r a of a coastal Oregon stream following c l e a r c u t t i n g and slashburning.  Changes i n numbers and  species composition of the microflora communities as w e l l as a l g a l blooms following logging were observed.  They concluded that:  filamentous  a l g a l blooms are common i n streams influenced by the removal of the veget a t i o n from the surrounding watershed." This a l g a l growth may reduce l i g h t penetration causing the disappearance of benthic plants.  When the algae and any other plants decay, dissolved  oxygen l e v e l s may be lowered causing, i n severe cases, the death of other aquatic organisms and/or changes i n the species composition o f aquatic communities (Hynes, 1969; Werner, 1973). Loss of chemical nutrients i n streamwater may have important consequences f o r watershed s o i l p r o d u c t i v i t y (Likens e t al., 1970; Pierce et al.  1972).  Such losses have generally been ignored i n the past with the  emphasis on nutrient loss v i a timber removal (e.g. Ovington, 1962; Rennie, 1955).  To the writer's knowledge, the f i r s t comparison of nutrient losses  i n streams to nutrient losses through timber removal has only recently appeared.  This work, again from Hubbard Brook, found that, as a r e s u l t of  c l e a r c u t t i n g one-third of a watershed i n s t r i p s , the amount of n i t r a t e nitrogen removed i n timber was about the same as that removed i n streamwater the f i r s t two years a f t e r cutting, whereas calcium losses were s l i g h t l y greater, i n streamwater (Hornbeck  et'al.,  1973).  The authors indicated that  chemical losses i n streamwater a f t e r c l e a r c u t t i n g the e n t i r e watershed are  36  l i k e l y to be more than three times the losses from c l e a r c u t t i n g one-third of the watershed.  Although nutrient losses were small i n comparison to  the t o t a l s present i n the s o i l , the s i g n i f i c a n c e of such losses i s s t i l l unknown (Hornbeck et al., 1973; Pierce et al., 1972).  However, i t i s pos-  s i b l e that the s i g n i f i c a n c e f a r exceeds the actual proportions since the losses are l i k e l y to be of the b i o l o g i c a l l y active nutrients (Pierce et  al., 1972) . I n i t i a l r e s u l t s from Hubbard Brook, i n which complete removal of vegetation i n a watershed by cutting and herbicides caused n i t r a t e concentrations i n streamwater leaving the watershed to continuously exceed the U.S. recommended concentration f o r drinking water, suggested that c l e a r c u t t i n g might s i m i l a r l y impair the chemical q u a l i t y of streamwater for human consumption (Likens et al., 1970).  However, t h i s has not been confirmed by  more recent studies of commerical c l e a r c u t t i n g operations both a t Hubbard Brook  (Hornbeck et al., 1973; Pierce et al., 1972), and i n Oregon  (Brown  et al., 1973; Fredriksen, 1971), although i n one Oregon study (Fredriksen, 1971) ammonia and manganese concentrations i n streamwater exceeded the U.S. maximum permissible concentrations f o r drinking water f o r a twelve day period immediately following slashburning. (f)  Dissolved organic chemicals - Soluble tannins and l i g n i n - l i k e sub-  stances which produce yellow and brown colours i n water can be leached out of bark (Narver, 1971; S e r v i z i et al., 1971).  This leachate from slash  has been found to range from non-toxic to s l i g h t l y t o x i c f o r young salmon and trout (Narver, 1971; Pease, 1974; S e r v i z i et al., 1971) but Narver (1971) considered that t o x i c , l e v e l s would be reached only where a large accumulation of debris c o l l e c t s i n a very small stream.  In such a stream, anaerobic  37  b a c t e r i a l d e c o m p o s i t i o n o f o r g a n i c m a t e r i a l may hydrogen (g)  also occur, producting t o x i c  sulphide.  D i s s o l v e d oxygen - C l e a r c u t t i n g o p e r a t i o n s which d e p o s i t s l a s h i n a  stream t e n d t o lower the amount o f oxygen d i s s o l v e d i n t h a t s t r e a m . i s due t o t h e consumption ing  This  o f oxygen by a q u a t i c organisms which a r e decompos-  t h e s l a s h m a t e r i a l and t o the l e a c h i n g o f s o l u b l e o r g a n i c s u b s t a n c e s  from t h e s l a s h .  Many o f t h e s e s u b s t a n c e s , which i n c l u d e the wood s u g a r s ,  e x e r t a c o n s i d e r a b l e c h e m i c a l oxygen demand as w e l l as a b i o l o g i c a l oxygen demand' ( H a l l and L a n t z , 1969; partment o f t h e I n t e r i o r ,  N a r v e r , 1971;  1970).  are  be l i t t l e  stream temperatures do not r i s e s i g n i f i c a n t l y  Burns, 1973;  U.S.  1971;  U.S.  a f f e c t e d by  clearcutting  (Burns, 1972;  Krammes and  Department o f t h e I n t e r i o r , 1970).  When s l a s h m a t e r i a l s  c o v e r e d w i t h a l a y e r o f sediment, as i s sometimes t h e case a f t e r  g i n g o p e r a t i o n s , d e c o m p o s i t i o n o f t h e s l a s h w i l l be slow and w i l l anaerobically.  occur  hydrogen  sulphide,  ammonia, methane, c a r b o n d i o x i d e , and hydrogen, which s l o w l y d i f f u s e t h r o u g h t h e o v e r l y i n g sediment  ( S e r v i z i et al.,  f l o w i n c r e a s e s and as water temperature d e c r e a s e s . water t e m p e r a t u r e s , c l e a r c u t t i n g may D e p l e t i o n o f streamwater  of  up  1971).  The amount o f oxygen d i s s o l v e d i n streamwater  i n c r e a s e s as streamThus, by  increasing  f u r t h e r lower d i s s o l v e d oxygen  levels.  oxygen by decomposer organisms w i l l be g r e a t e s t i n  summer when streamwater  Thus,  log-  The p r o d u c t s o f t h i s p r o c e s s w i l l decompose f u r t h e r u s i n g  up more oxygen i n the water, p r o d u c i n g t h e end p r o d u c t s :  the  De-  I f s l a s h i s k e p t o u t o f streams, on t h e  o t h e r hand, d i s s o l v e d oxygen l e v e l s may if  S e r v i z i et al.,  temperatures a r e h i g h and streamflow i s low.  s e v e r a l s y n e r g i s t i c p r o c e s s e s o p e r a t e i n summer t o lower t h e amount  oxygen d i s s o l v e d i n streamwater.  Although c l e a r c u t t i n g  increases  38  streamflow which tends t o i n c r e a s e and  slash deposition  oxygen l e v e l s , temperature  increases  appear more i m p o r t a n t so t h a t the g e n e r a l  c l e a r c u t t i n g i s t o d e c r e a s e oxygen l e v e l s i n the  summer.  The  e f f e c t of occurrence  of f r e s h e t s i n autumn, however, w i l l b r i n g d i s s o l v e d oxygen l e v e l s back t o near  saturation.  The  e f f e c t s o f d i s s o l v e d oxygen l e v e l s on f i s h  have been d i s c u s s e d Dissolved  by Narver  oxygen p l a y s  (1971) and  The  o f a stream i s s u p p l i e d b o t h by  D e b r i s and  (1969).  i n t e r c h a n g e from the stream and  by  sediment from c l e a r c u t t i n g o p e r a t i o n s covering  as w e l l as by  L a n t z , 1969;  1971;  a high  ground-  stream i s the main source  a s u b s t a n t i a l d e c r e a s e i n t h i s r a t e of i n t e r c h a n g e by exerting  and  oxygen d i s s o l v e d i n the i n t r a g r a v e l water  i t appears t h a t i n t e r c h a n g e from the  (Narver, 1971).  Lantz  development  an i m p o r t a n t r o l e i n b o t h the l o n g - t e r m  short-term s u r v i v a l of f i s h .  w a t e r , but  H a l l and  l i f e and  oxygen demand ( H a l l and  can  the  cause  gravel, Narver,  Pease, 1974). A l a r g e d e c r e a s e below s a t u r a t i o n i n the oxygen d i s s o l v e d i n the  g r a v e l water can hatching,  and,  cause a r e d u c t i o n  i n severe c a s e s , can  or cause m o r t a l i t y o f f r y .  o f f r y s i z e , slow growth, a d e l a y lower t h e  success of incubation  Thus, the s u r v i v a l , growth, and  general  intrain  of eggs fitness  o f young s a l m o n i d s i s d i r e c t l y r e l a t e d t o i n t r a g r a v e l d i s s o l v e d oxygen l e v e l s . S i m i l a r l y , the  s u c c e s s o f salmonids i s s t r o n g l y i n f l u e n c e d by  oxygen d i s s o l v e d i n the ing  f r c m 'the g r a v e l .  d e a t h or  surface  Growth and  l o s s o f w e i g h t can  d r o p s t o about 2 m g / l i t r e .  the amount o f  waters i n which the f i s h l i v e a f t e r emergfood  conversion  depend on t h i s oxygen  o c c u r i f the c o n c e n t r a t i o n  o f d i s s o l v e d oxygen  D a i l y f l u c t u a t i o n s i n d i s s o l v e d oxygen of 6  l i t r e o r more c a n g r e a t l y r e d u c e salmonid a p p e t i t e  and  and  growth  mg/  (Narver, 1971).  39  I n g e n e r a l , i t appears t h a t r e t e n t i o n o f s t r i p s o f v e g e t a t i o n a l o n g stream banks may s i g n i f i c a n t l y reduce t h e impact o f c l e a r c u t t i n g on aquat i c ecosystems.  A p a r t from t h e stream temperature c o n t r o l p r o v i d e d by  v e g e t a t i o n , t h e f o r e s t f l o o r beneath t h e v e g e t a t i o n may f i l t e r o u t any sediment b e i n g c a r r i e d by o v e r l a n d water f l o w and p l a n t r o o t s may t a k e up excess c h e m i c a l n u t r i e n t s b e i n g l e a c h e d o u t o f t h e c l e a r c u t a r e a (Brown, 1969; F r e d r i k s e n et al., 1973; Hornbeck  et al., 1973; S w i f t and Baker,  1973).  S t r e a m s i d e b u f f e r s t r i p s c a n a l s o p r o t e c t stream bank h a b i t a t f o r f i s h (Bustard, 1973; N a r v e r , 1972) and m a i n t a i n t e r r e s t r i a l i n p u t . o f f o o d streams  (Chapman and Demory, 1963; Warren et al., 1964).  into  Streamside buf-  f e r s t r i p s w i l l n o t , however, p r e v e n t stream s e d i m e n t a t i o n caused by l o g g i n g o p e r a t i o n s remote from t h e stream, as sediment may e n t e r a stream v i a s i d e c h a n n e l s (T.W. Chamberlin, Canada Department eries Service:  P e r s o n a l communication).  Burns  o f t h e Environment,  Fish-  (1970) has r e v i e w e d t h e  b e n e f i t s t o be o b t a i n e d by l e a v i n g s t r i p s o f v e g e t a t i o n b e s i d e s t r e a m s . The t i m i n g o f l o g g i n g o p e r a t i o n s i s a l s o i m p o r t a n t .  From t h e f i s h e r -  i e s v i e w p o i n t , s l a s h o r sediment i n streams i s p a r t i c u l a r l y h a r m f u l i n s p r i n g when eggs a r e i n c u b a t i n g and f r y are emerging  ( H a l l and L a n t z , 1969).  Winter l o g g i n g , as i n t h e i n t e r i o r o f B.C., a l t h o u g h c a u s i n g l e s s s o i l t u r b a n c e , may s t i l l  dis-  cause heavy s e d i m e n t a t i o n o f streams from r o a d s and  l a n d i n g s , and can d e p o s i t much d e b r i s i n stream c h a n n e l s s i n c e t h e s e chann e l s may n o t be seen i n w i n t e r and heavy o v e r n i g h t s n o w f a l l may c o v e r s l a s h , l e a v i n g i t t o be exposed o n l y a f t e r s p r i n g m e l t Department  o f t h e Environment, F i s h e r i e s S e r v i c e :  Reviews  (T.W. C h a m b e r l i n , Canada P e r s o n a l communication).  o f t h e l i t e r a t u r e p e r t a i n i n g t o some o f t h e e c o l o g i c a l  effects  o f c l e a r c u t t i n g have r e c e n t l y appeared i n "Report o f t h e P r e s i d e n t ' s A d v i s o r y P a n e l on Timber and t h e Environment", U.S. Government P r i n t i n g O f f i c e , 1973.  Objectives of the Thesis  When the l i t e r a t u r e was reviewed early i n 1970, the r e s u l t s from the e a r l i e r Hubbard Brook experiments  (Bormann et al., 1968; Likens et at.,  1969; Smith et dl., 1968) suggested that f o r e s t c l e a r c u t t i n g might increase chemical fluxes i n streams which might have s i g n i f i c a n t implications f o r the  q u a l i t y of the streamwater as well as f o r the p r o d u c t i v i t y of t e r r e s -  t r i a l f o r e s t ecosystems.  The review a l s o indicated that knowledge of the  e f f e c t s of logging on streams on the west coast of North America was l i m i t e d to those parameters, such as sediment load and temperature, which d i r e c t l y affected f i s h populations, but that l i t t l e was known about stream chemistry. Consequently, t h i s study was undertaken to attempt t o answer the f o l lowing questions: (1)  What i s the chemical behaviour o f small streams flowing through r e l a t i v e l y undisturbed f o r e s t watersheds i n the Coastal Western Hemlock biogeoclimatic zone of B.C.?  (2)  How i s t h i s behaviour affected by clearcutting?  (3)  What a d d i t i o n a l e f f e c t s are imposed by broadcast slashburning?  (4)  Are any changes i n streamwater  chemistry s i m i l a r t o changes i n s o l u -  t i o n chemistry elsewhere i n the ecosystem? Due t o time constraints of the study and because  the completion o f  c l e a r c u t t i n g operations was unavoidably delayed s i x months, the study of the  e f f e c t s of broadcast slashburning had to be abandoned and only the i n i -  t i a l e f f e c t s of c l e a r c u t t i n g on f o r e s t and stream biogeochemistry could be considered.  The objectives of the thesis are therefore l i m i t e d to ( 1 ) ,  and (4) above.  (2)  41  CHAPTER 2.  (1)  DESCRIPTION OF THE STUDY AREA  Location Five watersheds were studied i n the University of B.C. Research Forest,  approximately 60 km east of Vancouver, B.C.  (Figure 2.1).  Three (watersheds,  A, B, and C) were equipped with stream gauging devices and located between 140 and 450 m above sea l e v e l .  The other two (watersheds D and E) were located  between 315 and 400 m above sea l e v e l . (2)  Climate The study area has a Cfb climate (Koppen, 1936), which i s described as  marine warm temperate  rainy (mesothermal).  I t has no d i s t i n c t dry season, with  the d r i e s t summer month receiving more than 3 cm of r a i n .  Summer i s the d r i e s t  season, however, and more than 70% of the t o t a l p r e c i p i t a t i o n f a l l s i n the 6 months between September and A p r i l .  Average annual p r e c i p i t a t i o n varies from 220  cm at the lower southern end of the area to 270 cm at the higher northern end, nearly a l l of which i s the form of r a i n (Figure 2.2).  Snow occasionally  accumulates to depths of 30 cm during the winter months but i t r a r e l y remains f o r more than 1-2 weeks.  Average annual p r e c i p i t a t i o n f o r the watersheds i s  given i n Table 2.1, and p r e c i p i t a t i o n during the study period i s given i n Table 2.2. Table 2.1  Annual average p r e c i p i t a t i o n f o r the 3 gauged watersheds at Haney (based on 16 years data) Watershed A  226 cm  Watershed B  238 cm  Watershed C  254 cm  Watershed B + C  247 cm  R n to  H f o  O  k cr H-  0 0 3  Hi  rt  i (0  ft 6 »<  pj R  (H  Kilometres  5  to  P  "Administration" (219.1)  44  The values i n Table 2.1 are based on annual precipitation of 219 cm for the University of B.C. Research Forest "Administration" weather station and calculated from the isohyetal map of the area (Figure 2.2).  Table 2.2 Precipitation at Haney during the study period  1958-1974 (16 years) average  1970  1971  1972  1973  1974  January  29.1  50.2  21.3  17.8  40.6  February  22.9  33.0  30.4  13.1  30.5  March  20.1  31.1  42.0  16.6  April  16.4  9.6  18.3  4.4  25.8 •*• Study terminated  May  9.5  5.9  6.4  8.1  June  8.8  15.2  9.1  13.9  July  7.1  5.8  21.9  4.7  August  8.0  3.9  6.3  4.2  15.1  25.9  9.2  September  15.6  Study commenced -»• 17.1  October  24.1  16.5  27.8  7.6  23.7  November  26.2  22.8  34.4  24.9  31.7  December  31.3  38.3  15.3  52.0  29.2  247.3 266.1  176.6  Year  219.1  A l l values are i n cms for the University of B.C. Research Forest "Administration" weather station.  Summers are cool with an average daily mean temperature for the warmest month of about 17°C. The average daily mean temperature for the coldest month i s close to 0°C. Fog and mist are common. Due to the r e l a t i v e l y mild climate  45  the s o i l s are seldom frozen, and then only b r i e f l y and s u p e r f i c i a l l y . Temperature and r a i n f a l l data f o r two weather stations close to the study area are given i n Table 2.3, and the l o c a t i o n of the weather stations i s shown i n Figure 2.2.  Table 2.3  Climatological data f o r two weather stations at Haney. Average values f o r a 16 year period between 1958 and  1974.  Administration  (elevation 145 m)  maximum minimum precipitation temp. (°C) temp. (°C) (cm)  Spur 17 (elevation  375 m)  minimum precipitation maximum temp. (°C) temp. (°C) (cm)  -3.2  31.8  1.8  -2.6  23.3  20.1  2.0  -3.3  21.4  16.4  9.2  January  3.9  -1.1  29.1  February  7.4  1.1  22.9  March  9.3  1.5  -0.5  1.2  17.4  15.7  7.6  10.6  8.8  16.7  9.6  10.7  11.7  7.1  21.9  13.4  8.1  22.0  11.1  8.0  19.0  11.4  8.6  September  18.1  9.4  15.6  18.5  13.5  17.1  October  13.3  6.2  24.1  8.7  6.8  26.4  November  8.2  2.1  26.2  2.0  0.1  27.0  December  4.9  0.3  31.3  2.3  1.4  32.3  April  12.4  3.8  May  17.3  6.9  9.5  June  19.9  10.2  July  22.8  August  Mean annual t o t a l  219.1  Mean annual t o t a l  The table was calculated from c l i m a t o l o g i c a l records published  234.7*  i n the  Annual Reports of the University of B.C. Research Forest and on f i l e at the University of B.C. Research Forest.  46  *E. H e t h e r i n g t o n  ( F o r e s t r y S e r v i c e , Environment Canada:  Personal  communication) measured p r e c i p i t a t i o n a t the U n i v e r s i t y of B.C. u s i n g h i s own tor  network o f c o l l e c t o r s and  a t Spur 17 was  t o t a l o f 234.7 cm (3)  t h a t the p r e c i p i t a t i o n  u n d e r c o l l e c t i n g p r e c i p i t a t i o n by 8%. s h o u l d be  Geology, l a n d f o r m s , and The  concluded  253.5  Research F o r e s t  Thus, the mean annual  cm.  soils  bedrock c o n s i s t s p r e d o m i n a n t l y o f a c i d igneous r o c k s - d i o r i t e ,  d i o r i t e , q u a r t z d i o r i t e , and  grano-  some g r a n i t e s y e n i t e and monzonite - w i t h some  i s o l a t e d masses o f v o l c a n i c and the study  collec-  sedimentary r o c k s .  The most common r o c k  type  in  a r e a i s q u a r t z d i o r i t e which c o n t a i n s more b i o t i t e t h a n hornblende  (Roddick, 1965).  O u t c r o p s and exposures o f the q u a r t z d i o r i t e d i s p l a y smooth,  s u p e r f i c i a l l y weathered s u r f a c e s r e l a t i v e l y f r e e of. open j o i n t s ,  suggesting  that  t h e bedrock i s g e n e r a l l y impermeable. Most o f the a r e a was by a t l e a s t t h r e e glaciations was  i s grey  occurs  (Seymour, Semiamu, and Vashon) and p o s s i b l y f o u r  (Armstrong, 1956) .  o v e r r i d d e n by  till  c o v e r e d by i c e d u r i n g the P l e i s t o c e n e , b e i n g a f f e c t e d  The  (Sumas) major  m a t e r i a l d e p o s i t e d by an advancing  the i c e t o g i v e r i s e t o t h e p r e s e n t b a s a l t i l l .  i n c o l o u r , h i g h l y compacted and  glacier  This basal  impermeable t o w a t e r .  When i t  i t u s u a l l y determines the lower l i m i t o f r o o t p e n e t r a t i o n and o n l y  r a r e l y do r o o t s p e n e t r a t e  i t v i a cracks.  r e t r e a t of the g l a c i e r i s a b l a t i o n t i l l . m a n t l e , was particularly  M a t e r i a l d e p o s i t e d l a t e r and This t i l l ,  p a r t o f the study  during  which forms the p r e s e n t  reworked i n p l a c e s by the meltwaters o f the r e c e d i n g i n the southern  very  a r e a , and  soil  glaciers,  i s mixed i n p l a c e s  with  colluvium. The C,  southern  h a l f o f watershed A b e l o n g s t o L a c a t e ' s  (1965) l a n d a s s o c i a t i o n  d e s c r i b e d as a f l a t t o g e n t l y r o l l i n g complex o f g l a c i o - f l u v i a l outwash  and  47  sub-stratified d r i f t deposits.  Outwash sand and gravel terraces and deltas are  the common landforms and the s o i l materials are usually quite deep and of variable texture. Although the s o i l i s generally permeable, tree rooting i s restricted on some terraces by discontinuous iron pans and cemented layers. Temporary perched water tables occur above these layers for short periods during the year.  Except for terrace scarps and the occasional bedrock k n o l l ,  the topography i s f l a t to gently sloping (0-20%). The northern half of watershed A and a l l of watersheds B, C, D, and E belong to Lacate's land association B, described as h i l l y to gently r o l l i n g , g r a n i t i c cored uplands and valleys.  Gravelly sandy loam colluvium overlying unweathered  basal t i l l and/or bedrock i s the most common structural pattern of the terrain. In g u l l i e s and low-lying areas, reworked t i l l and poorly sorted sands and gravels mantle basal t i l l .  Patches of talus and varved lacustrine clays and s i l t s are  minor inclusions. An organic cap often covers exposed bedrock.  In deep g u l l i e s  a deep muck i s often present. • Soils i n watershed A are humo-ferric podzols (Canada S o i l Survey Committee, 1970) derived mainly from g l a c i a l outwash and c o l l u v i a l materials.  Close to the  stream they are described as very moist to wet deep s o i l s of variable texture (Lacate, 1965) . Away from the stream they are dry to s l i g h t l y moist, shallow, coarse textured (sandy loam to loamy sand) s o i l s . Soils i n watersheds B and C are predominantly humo-ferric podzols with small areas of humic gleysols i n a l l u v i a l f l a t s i n the valley bottom, and some l i t h i c f o l i s o l s on bedrock outcrops.  Adjacent to stream channels they are described  (Lacate, 1965) as dry to s l i g h t l y moist, deep, coarse textured s o i l s , and elsewhere as dry to s l i g h t l y moist, shallow, coarse textured s o i l s . were found to be predominantly sandy loam and loamy sand.  Textures  48  A detailed soil  survey o r c l a s s i f i c a t i o n  o f t h e U n i v e r s i t y o f B.C.  Research F o r e s t was n o t a v a i l a b l e , b u t n i n e t e e n watersheds. and  P r o f i l e d e s c r i p t i o n s are given  chemical data are given  (4)  i n Appendix I I and s o i l  i n Appendix I I I .  watersheds l i e i n t h e d r y subzone o f t h e C o a s t a l Western Hemlock  biogeoclimatic  zone o f B.C. ( K r a j i n a , 1959, 1965, and 1969) and a r e c o v e r e d  m o s t l y by t h e c o n i f e r o u s  Thuja plioata  (red a l d e r ) ,  ( b i g l e a f maple) and  i s given  described  and  (western hemlock),  Pseudotsuga menziesii  Populus trichocarpa  o c c a s i o n a l o p e n i n g o r wet s i t e . species  Tsuga heterophylla*  species  (western r e d c e d a r ) ,  Alnus rubra  maorophyllum  (Douglas-fir)  ( b l a c k cottonwood),  Betula papyrifera  with  Acer  (western w h i t e b i r c h )  i n the  The r e l a t i v e abundance o f t h e major t r e e  i n T a b l e 2.4.  Understory vegetation  i s v a r i e d and w i l l be  under b i o g e o c o e n o s e s .  T a b l e 2.4  Watershed A  B  R e l a t i v e d i s t r i b u t i o n o f t h e major t r e e s p e c i e s i n • watersheds A, B, and C.  Species  Percentage by numbers  C  Percentage by volume prism cruii  Hemlock  37  41  Cedar  28  22  Douglas-fir  35  37  Hemlock  79  82  Cedar  15  12  6  6  Douglas-fir  *  physical  Vegetation The  some  s o i l p i t s were dug i n t h e  Hemlock  50  -  Cedar  36  -  Douglas-fir  5  -  Birch  9  - '  A l l l a t i n names a r e from T a y l o r s c i e n t i f i c names a r e g i v e n  (1966) and S c h o f i e l d  i n Appendix XV.  (1968).  •  Complete  49  (a)  Forest cover - Forest cover i s shown i n Figure 2.3; the units are  described below. Names of the units are descriptive and have been used only for the purposes of this study. Watershed A 1.  T a l l Forest:  Covers 14.2 ha (61% of watershed A) and was  clearcut (Figure 2.5).  entirely  This unit consists predominantly of western hemlock and  western red cedar with some Douglas-fir and very small amounts of red alder and bigleaf maple. The trees grew up after a f i r e i n 1868 and are mostly 70-90 years old. Understory vegetation i s described under biogeocoenoses. 2.  Plantation, 1961:  Covers 7.0 ha (31% of watershed A).  The T a l l  Forest on this area was clearcut i n 1957, p a r t i a l l y s c a r i f i e d , then planted with Douglas-fir and western hemlock i n 1961. leuaodermis  }  Gaultheria  shallon  3  I t now contains much red alder, Rubus  and grasses.  Sections of i t near the creek  which were not s c a r i f i e d contain remnants of the original stand as well as a l l aged Douglas-fir, western hemlock, western red cedar and red alder regeneration growing above a dense tangle of Rubus speatabilis  3  ursinus, and Gaultheria 3.  Ttevidium aquilinum, Rubus  shallon.  F i e l d and Forest:  Covers 1.9 ha (8% of watershed A) and consists of  several grass-covered f i e l d s surrounded by small stands of the T a l l Forest. f i e l d s were created by clearing the forest and planting grass i n 1913 U.B.C. Research Forest:  The  (J. Walters,  Personal Communication).  Watershed B 1.  T a l l Forest:  clearcut (Figure 2.5). 4.  Covers 16.3 ha (55% of watershed B), 13.1 of which were I t was the same cover type as i n watershed A.  Plantation, 1958:  Covers 4.8 ha (20% of watershed B).  The T a l l  Forest on this unit was logged i n 1958, slashburned i n the autumn of 1960, then  -5JL Figure  2.3  Forest cover  Legend 1. 2. 3. 4. 5. 6. 7. 8.  Scale — J —  200  Mature f o r e s t P l a n t a t i o n , 1961 F i e l d and F o r e s t P l a n t a t i o n , 1958 Immature F o r e s t P l a n t a t i o n , 1959 Swamp P l a n t a t i o n , 1964  (metres)  1~  400  600  51  immediately planted with Douglas-fir. I t now consists of densely stocked Douglas-fir and western hemlock with some red alder. Where the tree canopy i s very dense there i s no understory vegetation; elsewhere, Pteridium Gaultheria shallon, Rubus spectabiUs Vacoinium ovalifolium  3  splendenSy  Polystichum  3  Rubus ursinus  3  Vacoinium  aquitinum  3  parvifolium  3  munitum, Linnaea borealis HyZocomium 3  and Eurhynchium oreganum are the major understory species.  5. Immature Forest:  Covers 0.6 ha (2% of watershed B).  This unit was  logged by railway i n the 1920's and now consists predominantly of immature western hemlock, western red cedar, western white birch, and Douglas-fir with considerable quantities of red alder and Ace? civcinatum  (vine maple).  Understory vegetation i s described under biogeocoenoses. 6. Plantation, 1959: Covers 2.3 ha (10% of watershed B).  The T a l l Forest  on this unit was logged i n 1956, slashburned i n 1958, then planted with Douglasf i r i n the autumn of 1959.  I t s vegetation i s identical to that of unit 4 except  that BZechnum spioant i s more prominant as an understory species. Watershed C 5. Immature Forest:  Covers 39.1 ha (89% of watershed C) and i s described  above. 6. Plantation, 1959: Covers 3.4 ha (8% of watershed C) and i s described above. 7. Swamp: Covers 1.5 ha (3% of watershed C) and occurs only i n slight depressions.  Tree cover i s sparse, usually confined to western red cedar and  the occasional western hemlock growing on decaying logs. Lesser vegetation i s described below under Lysichiturn-western red cedar biogeocoenoses. Watershed D 1.  T a l l Forest:  clearcut (Figure 2.5).  • Covers 6.9 ha (80% of watershed D), 1.7 of which were I t s vegetation i s described above.  52  8.  P l a n t a t i o n , 1964:  F o r e s t o f t h i s u n i t was Douglas-fir seedlings western hemlock and  C o v e r s 1.7  l o g g e d i n 1964  red a l d e r .  (20% o f watershed D).  and  i n s p r i n g 1966.  aquilinum, Rubus spectdbilis Gaultheria  ha  s p r i n g 1965,  The  Tall  then p l a n t e d  with  Other t r e e s p e c i e s now  Understory species  present  are m a i n l y  Pteridium  Rubus ursinus, Vacoinium parvifolium,  s  include  and  shallon.  Watershed E 1. clearcut (b)  T a l l Forest: ( F i g . 2.5) .  C o v e r s 10.4  ha  Its vegetation  (100%  o f watershed E ) , 2.8  i s described  above,  Biogeocoenoses The  U n i v e r s i t y o f B.C.  biogeocoenoses  Research F o r e s t was  ( K r a j i n a , 1965  t i o n o f s o i l s , l a n d f o r m s , and  and  1969)  ecologically classified  by K. K l i n k a .  vegetation.  This involved a  O n l y the v e g e t a t i o n  b i o g e o c o e n o s e s w i l l be b r i e f l y d e s c r i b e d  here.  the Ph.D.  completed) s h o u l d  t h e s i s o f K. K l i n k a  (yet t o be  B i o g e o c o e n o s e s are shown i n F i g u r e The  o f which were  major p l a n t s p e c i e s  l i s t e d i n order Group 1. t o p s and  of  The  overstory  shallon, Vacoinium parvifolium, and  the mosses  Tree species  These b i o g e o c o e n o s e s are  i s q u i t e open and  are  c o n s i s t s of  found on  ridge  Douglas-fir,  Understory plants include  Gaultheria  Mahonia nervosa, Pteridium qquilinum, Rubus  loreus  3  and  Moss-Western Hemlock:  g e n t l e r s l o p e s where t h e r e overstory  consulted.  Hylocomiun splendens, Eurhynchium oreganum, Plagiothecium  undulatum, Rhytidiadelphus Group 2.  information  importance.  western r e d c e d a r , and western hemlock.  ursinuSj  the  as a r r a n g e d i n t o f i v e main g r o u p s .  found i n each group a r e g i v e n below.  Gaultheria-Douglas f i r :  dry spurs.  2.4  considera-  component o f  F o r more d e t a i l e d be  into  is little  i s r a t h e r dense and  some  Sphagnum sp.  in  These biogeocoenoses are  depressions. found on  the  i n f l u e n c e o f s u b s u r f a c e seepage water.  c o n s i s t s o f western hemlock, D o u g l a s - f i r ,  and  The  54  western red cedar.  Polystichum  Understory plants include  muntium, Vaccinium alaskaense,  austriaca,  Rubus spectabilis,  Vaccinium parvi folium,  Gaultheria shallon,  Rubus ursinus, Trientalis  Dryopteris  latifolia,  and the mosses  Hylocomium splendens, Eurhynchium oreganum, Plagiothecium undulatum, Rhytidiadelphus Group 3.  loreus, and Isothecium  stoloniferum.  Polystichum-Western Red Cedar:  These biogeocoenoses usually occur  on the lower slopes where subsurface seepage water i s important.  The overstory  i s moderately dense and consists of western red cedar, Douglas-fir, and western hemlock, with small amounts of b i g l e a f maple and red a l d e r . include  Acer circinatum, Sambucus pubens, Vaccinium parvifolium,  alaskaense, Menziesia ferruginea, Rubus spectabilis, Polystichum  Pteridium  Vaccinium  aquilinum,  munitum, Blechnum spicant, Athyrium filix-femina,  austriaca, borealis,  Understory plants  Comus canadensis, Gaultheria shallon, Tiarella  trifoliata,  and the mosses Hylocomium splendens, Rhytidiadelphus  Rhizomnium glabrescens, stoloniferum,  Rhizomnium nudum, Plagiothecium  Dicranum fuscescens,  Dryopteris Linnaea  loreus,  undulatum, Isothecium  Dicranum scoparium, Eurhynchium oreganum,  and Hypnum circinale. Group 4 .  Stream Edge Biogeocoenoses:  v a l l e y bottoms near streams.  These biogeocoenoses occur only i n  The overstory i s moderately dense and consists of  western hemlock, western red cedar, and Douglas-fir, with an occasional red alder and black Cottonwood.  ferruginea,  Understory plants include  Vaccinium alaskaense,  Rubus spectabilis,  Acer circinatum,  Vaccinium parvifolium,  Athyrium filix-femina,  Menziesia  Oplopanax horridus,  Dryopteris austriaca,  munitum, Blechnum spicant, Gymnocarpium dryopteris, Tiarella  Polystichum trifoliata,  Lactuca  muralis, Gaultheria shallon, and the mosses Hylocomium splendens, Eurhynchium oreganum, Rhytidiadelphus Plagiothecium undulatum.  loreus, Rhizomnium glabrescens, Rhizomnium nudum, and  55  Group 5. Lysichitum-Western Red Cedar:  These biogeocoenoses occur i n wet  depressions within areas which are f l a t or only gently sloping.  The overstory  i s r e l a t i v e l y open and dominated by western red cedar with lesser amounts of western hemlock and Douglas-fir.  Rubus spectabilis  3  Dryopteris austriaca,  Lysichitum americanum, Tiarella Eurhynchium stokesii, (5)  Understory plants include  Vacoinium aZaskaense,  Athyrium fiZix-femina,  trifoZiata,  Btechnum spicant  3  and the mosses Rhizomnium punctatum,  and Sphagnum sp.  Watershed d e s c r i p t i o n Physical c h a r a c t e r i s t i c s of the f i v e watersheds are given i n Table 2.5.  Table 2.6 indicates that the two streams, D and E, despite considerably smaller watershed areas and shorter channel lengths, have only s l i g h t l y lower discharges than the stream leaving watershed A, which probably r e f l e c t s t h e i r shallower soils.  Discharges f o r streams D and E were measured at the end of a road culvert  through which the two streams pass downstream of t h e i r confluence.  Table 2.5  Physical c h a r a c t e r i s t i c s of the watersheds a t Haney  Elevation (m)  Channel length (m)  Average stream  Drainage density  Average watershed  7° upper 3° lower  A  145  310  670  275  40.9  N-»-S  upper lower  B  235  330  610  872  61.8  N-+S  515°  C  295  455  855  460  29.9  NNE+SSW  3°  D  315  390  275  -  -  NNE+SSW  4j°  19°  E  315  400  290  _  —  ESE+WNW  5h°  14°  3  12° 7°  56  T a b l e 2.6  R e l a t i v e watershed areas and stream d i s c h a r g e s  Watershed A Watershed  area  (ha)  23.1  B 24.0  C 44.0  D  E  8.6 10.4 combined  v  Stream d i s c h a r g e  (25/9/73 - 2 p.m.)  Stream d i s c h a r g e  (30/10/73  All  - 1 p.m.)  1.5  6.1  3.6  2.4  12.9  49.4  28.4  20.7  d i s c h a r g e s are i n l i t r e s / s e c .  The l o c a t i o n o f c l e a r c u t s and major roads w i t h i n the watersheds i s g i v e n i n Figure  2.5.  58  CHAPTER 3.  EXPERIMENTAL METHODS  (1)  F i e l d i n s t r u m e n t a t i o n and  (a)  Streamwater - S h a r p - c r e s t e d 120° V-notch w e i r s were c o n s t r u c t e d on  c r e e k s d r a i n i n g two  sampling  s m a l l watersheds.  the two watersheds was  techniques  The  e n t i r e d r a i n a g e o f the s m a l l e r o f  i n c l u d e d i n the experiment.  o n l y the lower r e g i o n was  On  the l a r g e r  i n c l u d e d i n the treatment p a r t o f the  d e s i g n , w h i l e the upper r e g i o n a c t e d as an u n t r e a t e d c o n t r o l . from t h e lower t r e a t m e n t All  experimental I t was  (weir A)  each o f which measured water temperature a t the organic-mineral s o i l  remote r e c o r d i n g 3 - p o i n t thermographs  interface  (7 cm below t h e s u r f a c e a t  The V - n o t c h w e i r i n the  larger  equipped w i t h a Weathermeasure remote r e c o r d i n g 2 - p o i n t  thermograph which measured water temperature s o i l temperature  watershed  ( w i t h i n 3 m o f the w e i r o u t l e t ) , a i r  w e i r A and 18 cm below the s u r f a c e a t w e i r C ) . (weir B) was  stilling  The w e i r i n the  and the r e c t a n g u l a r w e i r i n the l a r g e r  (weir C) were equipped w i t h Lambrecht type 258  temperature  separated  a r e a by a r e c t a n g u l a r b r o a d - c r e s t e d w e i r .  w e l l s , R i c h a r d s - t y p e water l e v e l r e c o r d e r s , and thermographs.  watershed  watershed,  t h r e e w e i r s were equipped w i t h i n s t r u m e n t s h e l t e r s h o u s i n g  s m a l l e r watershed  the  ( w i t h i n 3 m o f the w e i r o u t l e t )  a t the o r g a n i c - m i n e r a l s o i l i n t e r f a c e  (16 cm below the  and  surface).  A l l water l e v e l r e c o r d e r s and thermographs had spring-wound c l o c k s and 7-day c h a r t s and were r e g u l a r l y c a l i b r a t e d  ( a p p r o x i m a t e l y once a f o r t n i g h t )  and  a d j u s t e d as n e c e s s a r y . The h e i g h t - d i s c h a r g e r e l a t i o n s h i p s o f the t h r e e w e i r s were determined low and i n t e r m e d i a t e flows by u s i n g a b u c k e t  and stopwatch  technique.  for  F o r the  r e c t a n g u l a r w e i r t h e s e measurements were f a c i l i t a t e d by b u i l d i n g a s m a l l  dam  59  upstream o f t h e w e i r t o d i v e r t t h e water i n t o a p i p e .  At intermediate  not a l l o f the water c o u l d be accommodated i n t h i s p i p e . o v e r f l o w i n t h e w e i r was  measured and  t h e low f l o w c a l i b r a t i o n c u r v e . the water f l o w i n g through stream  at intermediate  height of t h i s  the o v e r f l o w d i s c h a r g e determined  T h i s d i s c h a r g e was  from  added t o t h a t o b t a i n e d f o r  the p i p e t o o b t a i n the o v e r a l l d i s c h a r g e f o r the  flows.  For h i g h flows through  the r e c t a n g u l a r w e i r , a Kempten OTT u n i v e r s a l  -current meter, model 10.002, was through  The  flows  used t o determine d i s c h a r g e .  t h e two V - n o t c h w e i r s were determined  d i r e c t l y from the  High  flows  theoretical  w e i r c a l i b r a t i o n c u r v e by assuming t h a t the c l o s e s i m i l a r i t y between the .measured and t h e o r e t i c a l c a l i b r a t i o n c u r v e s  f o r low  and  intermediate  would a l s o be r e f l e c t e d a t t h e h i g h f l o w s .  Stage-discharge  flows  curves are given  i n Appendix I . Samples o f streamwater f o r c h e m i c a l a n a l y s i s were c o l l e c t e d once a week ( o c c a s i o n a l l y more f r e q u e n t l y ) immediately weirs.  upstream o f the ponds b e h i n d  Samples were c o l l e c t e d i n p o l y e t h y l e n e b o t t l e s .  the  At the beginning  of  the s t u d y t h e s e were washed w i t h warm d i l u t e h y d r o c h l o r i c a c i d , h o t water, d e i o n i z e d w a t e r between s a m p l i n g s . and was (b)  d i s c o n t i n u e d l a t e r i n the  The  a c i d r i n s e was  found t o be  c o l l e c t e d i n simple  systems, each c o n s i s t i n g o f a f u n n e l c o n t a i n i n g a p l u g o f spun  1 l i t r e ) v i a a rubber  unnecessary  study.  P r e c i p i t a t i o n - I n c i d e n t p r e c i p i t a t i o n was  ( " f i l t e r f i b r e " ) connected  and  polyethylene  fibreglass  t o a narrow necked p o l y e t h y l e n e c o n t a i n e r ( c a p a c i t y  stopper.  The  such t h a t the t o p o f t h e f u n n e l was  system was 40-70 cm  clamped t o a s u p p o r t i n g r o d  above the s o i l s u r f a c e and  above  any nearby v e g e t a t i o n . There was  a t o t a l o f f o u r p r e c i p i t a t i o n c o l l e c t o r s , each p l a c e d i n open  a r e a s a t t h e lower  and upper ends o f each o f the two  t r e a t e d areas  (Figure  3.1).  61  Snow was collected from the ground near the precipitation collectors by using the l i d of a wide necked 1 l i t r e polyethylene container to scoop the snow into the container. (c) Throughfall - Throughfall precipitation was collected i n polyethylene systems i d e n t i c a l to those f o r incident precipitation except that the collectors had a larger capacity (4.7 l i t r e s ) and rested on the s o i l surface. There was a t o t a l of 42 throughfall c o l l e c t o r s , 38 of which were located i n the study watersheds (2 near each of the 19 s o i l pits) and 4 of which were located i n a forest stand close to the southern end of the watersheds (Figure 3.1).  The 34 collectors associated with the 17 s o i l p i t s i n the treatment  areas were removed just p r i o r to clearcutting. Throughfall through slash was collected by placing appropriate pieces of slash i n the funnels of the polyethylene systems described above. To avoid errors due to contamination when setting up the collectors (when being set up, the slash pieces were wet and were collected and broken up by hand), a l l samples were discarded after the f i r s t week of r a i n .  There were 13 such  collectors, a l l located at the edge of the slash near weir B (Figure 3.1). Slash pieces i n the funnels are described i n Appendix VIII. A l l throughfall and incident precipitation systems were cleaned regularly, especially during warm periods when algae tended to develop i n the water. . Samples were collected once a fortnight or whenever possible during dry periods. (d)  S o i l s and s o i l water - The watersheds above weirs A and B were  stratified  into biogeocoenoses by f i e l d examination by Mr. Karel Klinka.  One  or more sites were selected within each different biogeocoenosis as being representative of that biogeocoenosis.  A s o i l p i t was dug on each s i t e , the  62  s o i l p r o f i l e was d e s c r i b e d culture Soil for  using  standard  methods  (U.S. Department o f A g r i -  Survey S t a f f , 1962), and samples o f each h o r i z o n were t a k e n  analysis.  Care was t a k e n n o t t o d i s t u r b t h e s o i l u p s l o p e o f t h e p i t .  A t o t a l o f 19 s o i l p i t s were dug, 8 i n watershed A, 9 i n watershed B, and 2 (numbers 9 and 10) o u t s i d e t h e t r e a t m e n t a r e a s  ( F i g u r e 3.1).  of t h e 19 s o i l p i t s were each equipped w i t h a s u r f a c e r u n o f f ( F i g u r e 3.2) and 2 t e n s i o n l y s i m e t e r s in  Fifteen  collector  ( F i g u r e 3.3) which were i n s t a l l e d  t h e s o i l on t h e u p s l o p e s i d e o f t h e p i t , one a t t h e o r g a n i c - m i n e r a l  i n t e r f a c e and t h e o t h e r  i n the mineral  soil  soil  70 cm below i t s s u r f a c e , o r  as c l o s e t o t h i s depth as p o s s i b l e i n s h a l l o w  soils.  Surface  runoff  col-  l e c t o r s were p l a c e d i n p o s i t i o n s judged most l i k e l y t o e x h i b i t s u r f a c e runoff. Two o f t h e r e m a i n i n g f o u r s o i l p i t s were l o c a t e d i n s h a l l o w s o i l s o v e r l y i n g b e d r o c k and each was equipped w i t h o n l y a s u r f a c e c o l l e c t o r and an o r g a n i c  layer lysimeter.  h i g h water t a b l e , had no m i n e r a l  soil  Another p i t , w i t h  organic runoff  a frequently  l y s i m e t e r b u t had t h e bottom p a r t o f  the p i t c o v e r e d t o p r e v e n t c o n t a m i n a t i o n o f t h e groundwater w h i c h was l e c t e d whenever p o s s i b l e .  col-  The l a s t p i t was l o c a t e d on a f l a t a l l u v i a l  w i t h a h i g h water t a b l e and t h e r e f o r e f u n c t i o n e d as a w e l l .  I t was  site  covered  t o p r e v e n t c o n t a m i n a t i o n o f groundwater which was sampled weekly. Surface i n Figure fall.  r u n o f f c o l l e c t o r s were c o n s t r u c t e d  3.2.  o u t o f p l e x i g l a s as shown  The upper p l e x i g l a s s h e e t was t o p r e v e n t c o l l e c t i o n i O f :  The c o l l e c t o r was i n s e r t e d i n t o t h e o r g a n i c  p l e x i g l a s sheet  The  Polyethylene  storage  tension  l a y e r so t h a t t h e bottom  was 1 cm below t h e s u r f a c e and the o u t l e t was t h e l o w e s t p a r t  of the c o l l e c t o r . polyethylene  through-  t u b i n g c o n n e c t e d t h e o u t l e t t o a 4.7  litre  container.  l y s i m e t e r s used i n t h i s study were o f two t y p e s .  One  type,  Figure 3.2  A surface runoff c o l l e c t o r  outlet  Figure 3.3  A tension lysimeter, type 1.  Figure 3.4  sidewalls  sidewalls  alundum d i s c 1^1  A tension lysimeter, type 2.  | - I — r i n g spacer r a d i a l spacer  plexiglas basal cone  s i l i c o n carbide cotton screen .perforated plexiglas (4 mm diameter holes)  to storage container as i n Figure 3.3 stopcock rubber stopper a i r hole  • storage container  64  which was constructed from plexiglas and c i r c u l a r porous alundum discs (10.2 cm i n diameter, 1.3 cm t h i c k ) , was similar to that described by Cole (1968) but with the addition of sidewalls cut from plexiglas pipe (Figure 3.3). These walls were 5 cm t a l l for the lysimeters i n the organic layer and 7.5 cm t a l l for the lysimeters i n the mineral s o i l .  The other type was a modified version of  that used by Bourgeois and Lavkulich (1972b).  I t had identical dimensions to  those of the f i r s t type but u t i l i z e d a 1 cm thick layer of 320 g r i t s i l i c o n carbide powder instead of an alundum disc.  Details are shown i n Figure 3.4.  The cotton screen prevented movement of s i l i c o n carbide through the outlet and into the storage container. The apparatus was f i l l e d with water before adding the s i l i c o n carbide to exclude any a i r pockets. Flexible polyethylene tubing led from the outlets of a l l lysimeters down to 4.7 l i t r e storage containers v i a 3-way stopcocks, as shown i n Figure 3.3. The stopcocks allowed the lysimeters to be switched o f f and f a c i l i t a t e d any repairs. When the polyethylene tubing was f u l l of water i t acted as a hanging water column which provided the necessary tension to the lysimeter plate.  Tensions of  90 cm of water, or as close to this as possible, were applied, 90 cm being a compromise between the shallow nature of the s o i l s and the tension of the water in the s o i l at f i e l d capacity. The alundum disc lysimeters were found to have a i r intrusion values of 150-190 cm of water, and the s i l i c o n carbide lysimeters, a i r intrusion values of 175-200 cm. (e) Tree and slash volumes 1. Standing trees - The volume of standing timber was estimated from a standard prism (BAF 30) cruise by the author i n 1971 using a random sampling pattern (26 points for 30.5 ha. of. forest).  65  2.  S l a s h - The l o a d i n g o f f i n e s l a s h  diameter) was e s t i m a t e d by randomly metre  ( p i e c e s l e s s than 1.3 cm i n  l o c a t i n g 24 c i r c u l a r p l o t s o f one square  ( r a d i u s 56.4 cm) each throughout t h e l o g g e d a r e a .  A l l the m a t e r i a l  w i t h i n each p l o t which o r i g i n a t e d from t h e s l a s h and which was l e s s than 1.3 cm i n d i a m e t e r was p l a c e d i n t o a p o l y t h e n e bag.  The m a t e r i a l i n t h e bags was  a i r - d r i e d and weighed weekly u n t i l t h e r e was no f u r t h e r change i n w e i g h t . S l a s h m a t e r i a l s g r e a t e r t h a n 1.3 cm i n d i a m e t e r were sampled  using the  l i n e i n t e r s e c t method o f Warren and O l s e n (1964) as m o d i f i e d by Van Wagner (1968).  Twenty-eight 30-metre s e c t i o n s o f sample l i n e were r u n i n t h r e e  d i f f e r e n t d i r e c t i o n s , each, o f t h e t h r e e l i n e s b e i n g a t an a n g l e o f 60° t o t h e others.  The f i r s t d i r e c t i o n was randomly  slash intersected  chosen.  The d i a m e t e r o f each p i e c e o f  by t h e l i n e was measured t o t h e n e a r e s t 0.2 cm.  The weight  o f s l a s h i n k g p e r square metre was determined from t h e f o r m u l a  w =  2 61SEd  2 adapted from Van Wagner (1968)  L where:  S i s t h e mean s p e c i f i c g r a v i t y o f t h e wood ( c a l c u l a t e d as t h e w e i g h t e d mean o f t h e s p e c i f i c g r a v i t i e s o f D o u g l a s - f i r , western hemlock, and w e s t e r n r e d c e d a r (Canadian F o r e s t r y Branch, 1951). I n t h e c a l c u l a t i o n s , bark was assumed t o have t h e same s p e c i f i c g r a v i t y as wood, which p r o b a b l y l e a d s t o a s l i g h t u n d e r e s t i m a t e o f s l a s h l o a d i n g s i n c e , i n the case o f b o t h western hemlock and w e s t e r n r e d c e d a r , t h e bark s p e c i f i c g r a v i t y i s g r e a t e r than t h e wood s p e c i f i c g r a v i t y (Smith and Kozak, 1971). d i s t h e p i e c e d i a m e t e r , measured i n i n c h e s , and L i s t h e l e n g t h o f t h e sample l i n e , measured i n f e e t .  R e s u l t s o f t h e t r e e and s l a s h volume s u r v e y s a r e g i v e n i n Appendix IX.  66  (2)  Chemical  analyses  (a)  Water - D i s s o l v e d oxygen c o n c e n t r a t i o n s were measured i n the streams  a t t h e time o f sample c o l l e c t i o n .  Water samples c o l l e c t e d i n the f i e l d were  brought t o t h e l a b o r a t o r y and b i c a r b o n a t e  c o n c e n t r a t i o n s , pH,  and  conductiv-  i t y were measured as soon as p o s s i b l e , u s u a l l y w i t h i n f o u r h o u r s o f lection.  The  samples were then s t o r e d a t 0°C  weeks, p r i o r t o b e i n g a n a l y z e d of a l l chemicals  alyses i s given i n Table  Table  3.1  K  Mg  + 2+  o Ca  Table +  .003  Mn  .0005  Al  .0003  2+  3  .5  S 0  4  + NH . 4  .01  sio  .01  Cl~  .2  HC0~  .005  H  +  3.2  3  +  2 °4 P  .09 1.0 .2  2  sio  + NH. 4  ±.01  HC0~  ±.1  ±.05  pH  ±.1  ±.002  cond.  ±.5  Al  ±.02  3  2 +  ±.1  H  ±.02  N 0  ±.01  analyses •  ±•5  ±.01  Ca  2+  .06  P r e c i s i o n o f the c h e m i c a l  Cl~  +  .2  are i n m g / l i t r e  ±.005  2  an-  by the a n a l y t i c a l methods  N 0  2 +  Mn  and p r e c i s i o n o f the  .003  Mg  Fe  limits  3.2  A l l values  Na  Detection  2 +  _ 3+ Fe  K  anions.  3.1  D e t e c t i o n l i m i t s of c h e m i c a l s • used.  +  Na  f o r a p e r i o d o f up t o s i x  f o r c a t i o n s and  analyzed are given i n Table  col-  s  +  2 °4 P  3  °4  A l l concentrations are i n m g / l i t r e . a t 25°C.  2  ±.05  ±.04 ±1.0 C o n d u c t i v i t y i s i n micromho/cm  67  D i s s o l v e d oxygen i n streamwater was measured u s i n g a YSI model 54 oxygen meter.  The i n s t r u m e n t  was c a l i b r a t e d i n t h e ambient a i r b e f o r e each measurement  and a l l measurements were c o r r e c t e d f o r streamwater temperature and a t m o s p h e r i c pressure. C o n d u c t i v i t y was measured u s i n g a Radiometer type CDM 2e c o n d u c t i v i t y meter w i t h a CDC 104 c o n d u c t i v i t y c e l l .  A l l measurements were c o r r e c t e d t o 25°C.  pH was measured u s i n g an O r i o n model 404 s p e c i f i c i o n meter w i t h  standard  g l a s s and s i l v e r / s i l v e r c h l o r i d e r e f e r e n c e e l e c t r o d e s . Bicarbonate with a standard  i o n was determined by t i t r a t i n g  a 25 ml a l i q u o t o f t h e sample  .0005 M h y d r o c h l o r i c a c i d s o l u t i o n t o an e n d p o i n t  o f pH 4.5,  u s i n g t h e O r i o n model 404 s p e c i f i c i o n meter (Black et at., p . 945, 1965). Cation concentrations  (potassium,  sodium, magnesium, c a l c i u m ,  iron,  manganese, and aluminium) were measured on a V a r i a n T e c h t r o n AA5 atomic a b s o r p t i o n s p e c t r o p h o t o m e t e r u s i n g an a i r - a c e t y l e n e flame f o r p o t a s s i u m , sodium, magnesium, i r o n , and manganese, and a n i t r o u s o x i d e - a c e t y l e n e and aluminium.  Standard  commercial s t a n d a r d s  s o l u t i o n s c o n t a i n i n g a l l t h e c a t i o n s were p r e p a r e d  following standard  from  ( F i s h e r S c i e n t i f i c Company).  Ammonium i o n , d i s s o l v e d s i l i c a , n i t r a t e and s u l p h a t e )  flame f o r c a l c i u m  and a n i o n c o n c e n t r a t i o n s  were measured on a T e c h n i c o n  ( C h l o r i d e , phosphate,  autoanalyzer  I I using the  c o l o r i m e t r i c methods:  Ammonium - The method u t i l i z e s t h e B e r t h e l o t r e a c t i o n i n which a b l u e c o l o u r e d compound  ( a b s o r p t i o n maximum 630 my) forms when a s o l u t i o n c o n t a i n i n g  ammonium i o n s i s added t o sodium phenoxide, f o l l o w e d by a d d i t i o n o f sodium hypochlorite  (Technicon  I n d u s t r i a l Systems, 1971a).  C h l o r i d e - C h l o r i d e l i b e r a t e s thiocyanate forms c o l o u r e d f e r r i c t h i o c y a n a t e  1  from m e r c u r i c  t h i o c y a n a t e which  ( a b s o r p t i o n maximum 480 my)in the p r e s e n c e o f  68  f e r r i c ions (Technicon Industrial Systems, 1971b) . Phosphate - Phosphate i n acid solution i s used to form molybdophosphoric acid which i s then reduced to the molybdenum blue complex (absorption maximum 885 my) by reaction with ascorbic acid (Technicon Industrial Systems, 1971c). Nitrate (Plus n i t r i t e ) - Nitrate i s reduced to n i t r i t e by hydrazine and a copper catalyst i n alkaline solution.  N i t r i t e then reacts with sulphanilamide  and N-(1-naphthyl) ethylene diamine dihydrochloride i n acid solution to form an azo dye (absorption maximum 520 my) (Johnson, 1972). Sulphate - An excess of barium chloride i s added to an a c i d i f i e d solution containing sulphate, forming barium sulphate. An equimolar (to barium) solution of methylthymol blue i s added to form a blue coloured chelate with the excess barium i n alkaline solution.  The amount of uncomplexed methylthymol blue  (absorption maximum 460 my) i s determined (Technicon Industrial Systems, 1971d). S i l i c a - The method i s based on the reduction of a silicomolybdate i n acid solution t o heteropoly blue (absorption maximum 660 my) by ascorbic acid (Technicon Industrial Systems, 1973). (b)  Mineral s o i l - Mineral s o i l samples were air-dried, crushed, then sieved to  determine the percentage (by weight) of particles less than 2 mm i n diameter. Subsequent analyses were performed on t h i s (less than 2 mm) fraction. Rock samples were i d e n t i f i e d by Dr. G. Richards of the Geology Department at the University of B.C.  ..  S o i l texture was obtained from a textural triangle (U.S. Department of Agriculture Survey Staff, 1962) after determining the p a r t i c l e size distribution by the Bouyoucos hydrometer sedimentation method (Day, 1950). S o i l pH was determined i n 1:1 soil:water and i n 1:2 soil:0.01 M CaCl2 suspensions (Black et al. , p. 914, 1965).  69  T o t a l c a r b o n was determined by d e c o m p o s i t i o n i n a Leco  induction  f u r n a c e f o l l o w e d by g a s o m e t r i c a n a l y s i s o f t h e c a r b o n d i o x i d e formed  (Black  et al. , p . 1346, 1965) i n a method developed by t h e ( U n i v e r s i t y o f B.C.) Department o f S o i l S c i e n c e  (1974).  T o t a l n i t r o g e n was determined by d i g e s t i n g t h e sample w i t h s u l p h u r i c a c i d f o l l o w e d by a c o l o r i m e t r i c d e t e r m i n a t i o n o f t h e ammonium i o n s u s i n g t h e p h e n o l - h y p o c h l o r i t e method  (Beecher and W h i t t e n ,  1970).  I r o n and aluminium were each determined by two methods: acid-ammonium o x a l a t e e x t r a c t i o n pyrophosphate  extraction  (McKeague and Day, 1966);  (Bascomb, 1968).  formed  1)  by an o x a l i c  2) by a  sodium  I n b o t h methods, t h e s u p e r n a t a n t  l i q u i d was a n a l y z e d f o r i r o n and aluminium by atomic a b s o r p t i o n s p e c t r o photometry  a f t e r c e n t r i f u g i n g the r e a c t i o n mixture.  C a t i o n exchange c a p a c i t y was determined by a pH 7, IM ammonium a c e t a t e leaching of the s o i l ,  f o l l o w e d by a m i c r o - K j e l d a h l d e t e r m i n a t i o n o f t h e a d -  s o r b e d ammonium i o n s .  Atomic a b s o r p t i o n s p e c t r o p h o t o m e t r i c a n a l y s i s o f t h e  l e a c h a t e was performed t o g i v e exchangeable  cation  (sodium, p o t a s s i u m , magnes-  ium, and c a l c i u m ) c o n c e n t r a t i o n s ( B l a c k et al. p . 891, 1965). (c)  O r g a n i c LFH l a y e r s  —'  '  B u l k d e n s i t y was determined by c u t t i n g o u t a c o r e o f t h e o r g a n i c l a y e r (3-4 c o r e s p e r s o i l p i t ) , required t o f i l l measuring  measuring  i t s volume  (by n o t i n g t h e volume o f water  t h e r e s u l t i n g h o l e l i n e d w i t h a t h i n p l a s t i c sheet) and  i t s weight a f t e r o v e n - d r y i n g a t 105°C.  LFH samples  were c r u s h e d and p u l v e r i z e d and s u b j e c t e d t o t h e . f o l l o w i n g  analyses: Ash c o n t e n t and o r g a n i c m a t t e r c o n t e n t were d e t e r m i n e d by a d r y a s h i n g p r o c e d u r e d e v e l o p e d i n t h e ( U n i v e r s i t y o f B.C.) Department o f S o i l S c i e n c e  70  (1974).  The percentage of organic matter was taken as (100 — % ash).  Total cations were determined by atomic absorption spectrophotometric analysis o f a solution prepared by d i s s o l v i n g the ash obtained above i n d i lute HC1.  Sodium, potassium, magnesium, calcium, i r o n , manganese, and  aluminium ions were  determined.  Total sulphur was determined  t u r b i d i m e t r i c a l l y as barium sulphate a f t e r  dry ashing the sample i n the presence of an a l c o h o l i c solution of MgfNO^^ and d i s s o l v i n g the ash i n warm, d i l u t e HCl (Black et al., p. 102, 1965; Jackson, p. 337, 1958). Total phosphorus  was determined  c o l o r i m e t r i c a l l y by the vanadomolybdo  phosphoric yellow colour method (Jackson, p. 334, 1958) a f t e r dry ashing the sample i n the presence of an a l c o h o l i c s o l u t i o n o f MgCNO^^  a n <  ! dis-  solving the ash i n warm, d i l u t e HCl. Total carbon was estimated from the loss i n weight a f t e r ashing, as described above under "ash content", and d i v i d i n g the percentage of organic matter by the conventional "Van Bemmelen f a c t o r " of 1.724 (Black et dl., p.  1367, 1965).  T o t a l nitrogen was determined by the phenol-hypochlorite method, as described above f o r the mineral s o i l . P_H was determined 0.01 M C a C l  2  i n 1:4 organic matter:water and 1:8 organic matter:  s l u r r i e s (Black et dl., p. 914, 1965).  Extractable Iron and aluminium were determined by the sodium pyrophosphate method, as described above f o r the mineral s o i l . Exchangeable cations and cation exchange capacity were determined by the pH 7 ammonium acetate method, as described above f o r the mineral s o i l .  71  CHAPTER 4.  1.  STREAM BEHAVIOUR  Stream H y d r o l o g y Instantaneous  t o 250  d i s c h a r g e s o f streams A, B,  litres/sec,  0.7  t o 1200  s p e c t i v e l y , d u r i n g the study The  stream hydrographs  litres/sec,  and  and  C have ranged from  0.2  t o 550  0.2  litres/sec.  re-  period. ( F i g u r e 4.1)  were c h a r a c t e r i z e d by h i g h  dis-  charges from October o r November u n t i l A p r i l f o l l o w e d by a d e c l i n e u n t i l a low was  reached  t a i n e d low  i n May  and s u s t a i n e d u n t i l the f o l l o w i n g autumn.  Sus-  f l o w s d u r i n g the w i n t e r p e r i o d o n l y o c c u r r e d when the c o l d a r c -  t i c a i r mass moved south over t h e Coast Mountains t o i n f l u e n c e the Lower Mainland.  Frozen  streams and water l e v e l r e c o r d e r s r e n d e r e d water  measurements i n a c c u r a t e d u r i n g such p e r i o d s which o c c u r r e d 31 days d u r i n g the t h r e e w i n t e r s o f measurement. t h e h e i g h t o f water f l o w i n g over mination  the w e i r s p e r m i t t e d  f a i r l y accurate  deter-  of d a i l y d i s c h a r g e s d u r i n g these p e r i o d s , however.  a storm d e p o s i t e d 12.9  of p r e c i p i t a t i o n f a l l i n g  cm o f r a i n i n 24 hours  i n 24 hours d u r i n g the  t o s o i l s which had been wetted by T h i s r e s u l t e d i n peak d i s c h a r g e s streams A, B, and  8.3  (the g r e a t e s t amount  3-1/2  y e a r s o f study)  o f 250,  1220,.and 550  ( F i g u r e s 4.2  o f the  f o u r days.  litres/sec. for  and  t r e n d s , the stream hydrographs were  f a l l s i n response t o i n d i v i d u a l  4.3).  soils.  precipita-  T h i s r a p i d response i s p r o b a b l y  t o the ease w i t h which water can t r a v e l through s o i l s and nature  on-  C respectively.  c h a r a c t e r i z e d by r a p i d r i s e s and t i o n events  F o r example, i n J u l y ,  cm o f r a i n the p r e c e d i n g  I n a d d i t i o n t o the o v e r a l l s e a s o n a l  low  f o r a t o t a l of  Manual measurement o f  O c c a s i o n a l summer storms caused h i g h d i s c h a r g e s . 1972,  level  related  a l s o t o the  shal-  H-  •X)  c H  CD  MERN DRILY DISCHARGE (LITRES/SEC) MEAN DRILY DISCHARGE (LITRES/SEC) MERN DRILY DISCHARGE (LITRES/SEC) cn o  Li  o o  cn o  o o  no  cn •• o  CO  o o  CO  cn o  — o o  —  ro cn  —  cn  CD  — —J cn  (V) o  CD  s  CD  3 & . HM  << & h1  W O D  X) CO Q a  3  4  0)  H iQ  (D  cn  pj cici-  3" CD  « X) cn o  •21  3 12 X)  K  <D H-  H cn  P) rr EC  ••01 3 CD  N3  73 F i g u r e 4.2  Response o f stream d i s c h a r g e t o p r e c i p i t a t i o n d u r i n g an October storm  Hourly p r e c i p i t a t i o n 1.-5-,  (cm)  l.CH 0.5" ,n-i  rThrpTTf 600  1200 12th  Ik.  1800  1 600  I 1200 13th  I  1800  1 October,  1973  74 F i g u r e 4.3  Response o f stream d i s c h a r g e t o p r e c i p i t a t i o n d u r i n g a January storm  Hourly p r e c i p i t a t i o n 1.0-  (cm)  0.5  600  1200 23rd  1800  600  1200 24th  1800 January,  1974  75 Stormflow a t Haney The explained  s o u r c e o f s t o r m f l o w a t Haney appears t o be complex and i s n o t r e a d i l y by any one c u r r e n t t h e o r y .  I n f a c t , t h e s o u r c e o f stormflow i s  g e n e r a l l y a s u b j e c t o f c o n s i d e r a b l e debate among h y d r o l o g i s t s a t p r e s e n t . F o r a l o n g t i m e , d i r e c t s u r f a c e r u n o f f was c o n s i d e r e d source o f s t o r m f l o w  (Horton,  by one i n which s u b s u r f a c e Chorley,  1967).  T h i s t h e o r y has been r e p l a c e d , however,  seepage water i s t h e major s o u r c e  A proponent o f t h i s t h e o r y ,  source area concept  (Hewlett,  b o t h s u r f a c e and s u b s u r f a c e surrounding  1945).  ( K i r k b y and  H e w l e t t , has advanced t h e v a r i a b l e  1961; Hewlett and H i b b e r t ,  1967).  This  considers  f l o w , g e n e r a t e d by an expanding and s h r i n k i n g zone  the p e r e n n i a l channel,  as t h e major c o n t r i b u t i o n t o stormflow.  zone expands i n response t o r a i n f a l l by l e n g t h e n i n g work and by e x p a n s i o n o f t h e s u b s u r f a c e Dunne and B l a c k  t o be t h e major  o f the surface channel  zones o f water s a t u r a t i o n .  The net-  However,  (1970a, b) have r e c e n t l y found t h a t most o f t h e storm r u n o f f  i n watersheds i n Vermont was produced from s u r f a c e r u n o f f which o r i g i n a t e d on a s m a l l p r o p o r t i o n o f t h e watershed. the water t a b l e r o s e t o t h e s o i l Few h y d r o l o g i c w e s t e r n B.C.  This surface runoff only occurred  when  surface.  s t u d i e s have been made o f t h e s o i l s i n mountainous  south-  Plamondon (1972), working i n Seymour watershed near Vancouver,  found t h a t d i r e c t s u r f a c e r u n o f f does o c c u r ,  but only over short  distances;  m i c r o t o p o g r a p h y p r e v e n t s i t from o c c u r r i n g on a l a r g e r s c a l e . De V r i e s and Chow  (1973) , a l s o working i n Seymour watershed,  considered  t h a t t h e h y d r o l o g i c b e h a v i o u r o f t h e s o i l was dominated by macrochannels ( l a r g e open c h a n n e l s i n t h e s o i l caused by decay o f r o o t s o r animal b u r r o w s ) . During a r a i n f a l l  e v e n t , a l a r g e p r o p o r t i o n o f t h e water was conducted down-  ward t h r o u g h t h e s e c h a n n e l s , t h e openings t o which were l o c a t e d near t h e s u r face o f the H horizon  i n the f o r e s t  floor.  Watershed h y d r o l o g i s t s have tended t o n e g l e c t t h e p o t e n t i a l s i g n i f i c a n c e o f macrochannels, d e s p i t e widespread e v i d e n c e f o r t h e i r e x i s t e n c e  ( e.g.  76 A u b e r t i n , 1971; J o n e s , 1971). A t Haney, s u r f a c e r u n o f f , o f the type d e s c r i b e d by Plamondon been o b s e r v e d .  (1972), has  I n a d d i t i o n , c l o s e e x a m i n a t i o n o f f a c e s i n the s o i l p i t s  r e v e a l e d an abundance  o f macrochannels  ( F i g u r e 4.4).  dug  Water has been o b s e r v e d  p o u r i n g r a p i d l y o u t o f some o f t h e s e macrochannels d u r i n g heavy  rains.  F u r t h e r m o r e , t h e water t a b l e has been o b s e r v e d t o r i s e and f a l l v e r y q u i c k l y i n response t o r a i n f a l l , days.  sometimes  r i s i n g and f a l l i n g more than 50 cm w i t h i n  two  T h i s s u g g e s t s t h a t the water t r a v e l s r a p i d l y down t h r o u g h t h e s o i l t o  the groundwater zone and t h e n q u i c k l y out o f t h i s zone. r o c k and b a s a l t i l l  Assuming t h a t t h e bed-  a r e r e l a t i v e l y w a t e r t i g h t , t h e groundwater must move i n t o  the streams. These o b s e r v a t i o n s suggest t h a t i n t h e watersheds a t Haney, s u b s u r f a c e f l o w o f water t h r o u g h macrochannel networks makes a s i g n i f i c a n t t o stream s t o r m f l o w .  contribution  Other s o u r c e s o f storm r u n o f f cannot be e x c l u d e d , however.  Dunne and B l a c k ' s e l e v a t e d water t a b l e s u r f a c e r u n o f f mechanism i s l i k e l y t o o p e r a t e when t h e s o i l s a r e v e r y wet, and d i r e c t s u r f a c e r u n o f f from a r e a s imm e d i a t e l y a d j a c e n t t o stream c h a n n e l s i s a l s o l i k e l y t o c o n t r i b u t e t o stormflow. Water budgets and  evapotranspiration  I s o h y e t a l maps ( F i g u r e 2.2)  were drawn i n o r d e r t o determine t h e amount  o f p r e c i p i t a t i o n f a l l i n g on each watershed.  T a b l e 4.1  summarizes  the p r e c i p i -  t a t i o n and stream r u n o f f d a t a f o r t h e two water y e a r s o f measurement. The e s t i m a t e d annual e v a p o t r a n s p i r a t i o n i s about 80-85 cm  (Table 4.1).  (ET) u s i n g simple water- budgets  T h i s does not agree v e r y w e l l w i t h o t h e r e s -  t i m a t e s o f ET f o r t h e watersheds and nearby a r e a s (Table 4.2). p a r t l y e x p l a i n e d by e r r o r s i n c a l c u l a t i n g water volumes.  T h i s may  be  The e s t i m a t e d maximum  p o s s i b l e e r r o r s i n v o l v e d i n c a l c u l a t i n g p r e c i p i t a t i o n i n p u t s a r e 10%and i n streamflow o u t p u t s , 30-35%. may  a l s o e x p l a i n the r e s u l t s .  Unrecorded l e a k a g e o f water from the watersheds I n t h i s r e s p e c t , t h e base o f w e i r C does n o t  F i g u r e 4.4  Macrochannels exposed i n the f a c e s o f s o i l  p i t no.  3  pits  r e s t on c o m p l e t e l y i m p e r v i o u s m a t e r i a l s .  I n a d d i t i o n , a v e r y s m a l l amount  o f leakage i s known t o o c c u r a t weir B.  T a b l e 4.1  P r e c i p i t a t i o n and r u n o f f f o r t h e watersheds  watershed  water year O c t . 1 - Sept.  30  a t Haney.  P (cm)  R (cm)  (P-R) (cm)  A  1971 - 1972 1972 - 1973  267 182  170 101  97 81  B + C  1971 - 1972 1972 - 1973  292 199  212 124*  80 75*  1972 - 1973**  204  104  C P  100  = i n c o m i n g p r e c i p i t a t i o n , as measured a t t h e U.B.C. R e s e a r c h Forest  " A d m i n i s t r a t i o n " s t a t i o n and c o r r e c t e d , t o g i v e t h e  p r e c i p i t a t i o n a c t u a l l y f a l l i n g on t h e watersheds,  u s i n g the  d a t a o b t a i n e d from t h e i s o h y e t a l maps. R  = r u n o f f as c a l c u l a t e d from w e i r d i s c h a r g e r e c o r d s .  Discharge  from w e i r B o r i g i n a t e s from watershed B p l u s watershed (P-R)  = an e s t i m a t e o f e v a p o t r a n s p i r a t i o n assuming and b a s a l t i l l t h e r e i s no  *  t h a t t h e bedrock  o f t h e watershed a r e w a t e r t i g h t and t h a t  l e a k a g e t h r o u g h o r around t h e w e i r s .  These v a l u e s may be a f f e c t e d by c l e a r c u t t i n g which took p l a c e d u r i n g t h e l a s t f o u r months o f t h e 1972-1973 water  **  C.  Weir C commenced  year.  o p e r a t i o n h a l f - w a y t h r o u g h t h e 1971-1972  water y e a r so t h a t d a t a f o r t h i s p e r i o d a r e n o t a v a i l a b l e .  79  T a b l e 4.2  E s t i m a t e s o f e v a p o t r a n s p i r a t i o n f o r Haney Method 1.  2.  water y e a r water y e a r  97 81  64 65  watershed B + C 1971- 1972 water y e a r 1972- 1973 water y e a r  80 75  63 64  100  65  watershed A 1971- 1972 1972- 1973  watershed C 1972-1973 water year-  3.  4. .  56  61  56  A l l v a l u e s a r e i n cms.  1.  E s t i m a t e d from water b u d g e t s i n t h e p r e s e n t s t u d y  2.  C a l c u l a t e d from d a t a s u p p l i e d by Dr. T.A. B l a c k and t h e f o r m u l a ET + _  S +  R^ where y I  s  the psychrometric  (Table 4.1).  constant,  S i s t h e s l o p e o f t h e s a t u r a t i o n vapour p r e s s u r e c u r v e a t t h e monthly mean temperature,  and  R^ i s t h e n e t r a d i a t i o n (McNaughton and B l a c k , 1973). 3.  E s t i m a t e d from d a t a o f Zeman (1969) u s i n g a s i m p l e water budget f o r t h e M i l i t z a Lake b a s i n a t Haney.  4.  C a l c u l a t e d by J . Cheng U n i v e r s i t y o f B.C.:  (Graduate  Student, F a c u l t y o f F o r e s t r y ,  P e r s o n a l communication) u s i n g Hamon's method  (Hamon, 1963) f o r an a r e a near watershed A. E f f e c t s o f c l e a r c u t t i n g on  streamflow  C l e a r c u t t i n g i s expected  t o i n c r e a s e t h e water y i e l d from watersheds  w i t h t h e most pronounced i n c r e a s e s d u r i n g t h e growing season when i n t e r c e p t i o n and t r a n s p i r a t i o n by v e g e t a t i o n i s g r e a t e s t (e.g. H i b b e r t , 1967).  80  Figure 4.5  Weekly maximum and minimum stream  temperatures  ^  71  I I I I 1 I I I I I 1  weekly maximum a i r temperature - weir A  i 1 I I 1I I I I 1 1 1 I I I 1 I !1  weekly minimum a i r temperature - weir A  I 1 I I 1 I 1 1 1 1 I 1 1 1 I I 1 I I I 1 I I | | | | | 1 1 |- | " S O N D J F M R B J j q s O M D J F M f l M J J f l S O M D J F H B  '^ ' 7  •  H71  I  H73  | |«174  |  F i g u r e 4.6  Streamwater  temperatures d u r i n g a t y p i c a l summer's day  and a t y p i c a l w i n t e r ' s Temperature  day  (°C)  5-,  -i  4  1  8  1  \  12 2nd J u l y ,  16 1972  1  20  —  >  '24  82  Figure 4.7  Streamwater temperature during the passage of an a r c t i c front  Temperature (°C)  4  8  12  16  3rd January, 1973  20  At Haney, increases have been observed during the f i r s t dormant season following clearcutting (Table 4.3}. S l i g h t l y greater increases from watershed A than from watershed B have occurred and can be attributed to the fact that a greater percentage of watershed A than watershed B was clearcut (61% versus 55%). These increases are probably mainly due to decreased interception losses. In October, the runoff was less than expected for both clearcut watersheds.  This may have been due to increased interception by slash and trees  which had not then been yarded. Lower temperatures and more complete yarding i n later months would have reduced interception and contributed to the general increase i n water y i e l d s .  83 T a b l e 4.3  Measured and p r e d i c t e d v a l u e s o f stream d i s c h a r g e f o l l o w i n g clearcutting. watershed A  (cm)  watershed B  (cm) 17.0  25.7  -8.7  4.1  36.7  34.5  2.2  18.2  8.9  59.2  33.8  25.4  30.9  24.0  6.9  50.8  45.5  5.4  Feb. 1974  31.4  23.4  8.0  44.4  44.4  0.0  Mar.  26.5  18.3  8.2  37.1  33.8  3.3  14.2  Oct. 1973  8.9  Nov.  1973  22.7  18.6  Dec.  1973  27.1  J a n . 1974  1974  -5.3  27.6  t o t a l increase  30.8  t o t a l increase  F o r t h i s 6-month p e r i o d , t o t a l d i s c h a r g e from watershed  C was 141.5 cm.  P r e d i c t e d v a l u e s r e f e r t o t h e d i s c h a r g e s e x p e c t e d , had t h e watersheds remained u n d i s t u r b e d , and were d e t e r m i n e d from t h e r e g r e s s i o n e q u a t i o n s : 1)  D  A  = .0641 + .7421 D  r e l a t i n g t o t a l d a i l y discharges a t weir  c  A  /° » A  t o t h o s e a t t h e c o n t r o l w e i r C, D^, and 2)  D  g  = .0124 + 1.1740 D  c  relating  t o t a l d a i l y d i s c h a r g e s a t weir B,Dg,  t o t h o s e a t t h e c o n t r o l w e i r C, D^  2.  Stream and s o i l a) The  Stream  (Appendix I V ) .  temperature  temperature  streams i n t h e i r u n d i s t u r b e d watersheds  a t e l y dense shrub and t r e e canopy. ( F i g u r e 4.12) shaded  were p r o t e c t e d by a moder-  T h i s , t o g e t h e r w i t h many f a l l e n  them i n summer p r e v e n t i n g temperatures from  much above 15°C d e s p i t e a i r temperatures  o f c l o s e t o 30°C.  trees  rising  In winter the  streams were r a r e l y c o v e r e d by snow so t h a t when a i r temperatures  remained  below f r e e z i n g  sometimes  f o r s e v e r a l days, t h e stream temperatures dropped,  t o below z e r o , and t h e stream s u r f a c e began t o i c e o v e r .  Complete  icing  o v e r was never observed, however, due m a i n l y t o stream t u r b u l e n c e and t h e l i m i t e d d u r a t i o n o f below f r e e z i n g The  stream i n watershed  temperatures.  B tended t o be c o o l e r t h a n t h a t i n watershed A  t h r o u g h o u t t h e y e a r , p r o b a b l y m a i n l y due t o i t s s l i g h t l y h i g h e r a l t i t u d e .  Figure 4.8 endReltahtoisoenshi n maxiinura streanwater temperatures In screams a. and I atpsstrbeeatmweeC Weakly uxlma atream temperatures i A versus C c BEFORE ClEfiRCUTTIHG fi RRER aCRSCUTTIHC  ^2cc  4 T Regr-ess1i.o70n9 a+ quation (r - 0.97) .9388 X  <OC3~  »  O.D  2.0  -i 4.0  *  1 6.0  r  B.C STREAM C f C )  — I —  ^  12.0  ttraan temperaturesiftversus C  18.0  ICO  , BEFORE aEBROjniNC 8 Rf TEH CLEARCUTTING  «fc*= CD t—R  IU9r«.fi o squtt•lon1.056 X T 0a .00 (r -. 0.696 7)  0.0  2.0  6.0  —|— STREAM C ^ C l "  12.0  -1 M.O  16.0  -1 IB.O  84  85  86  Figure 4.10 Weekly maximum and minimum soil temperatures o * *  soil near weir A soil near weir B soil near weir C  WEEKLY MAXIMUM S O I L  TEMPERATURES  ^  J fi S  0  N  O  J  F  H  R  H  J  J  R  S  O  N  D  J  F  H  R  M  J  J  R  weekly maximum a i r temperature - w e i r A  S  O  N O J f H f l  clearcuttingwatershed B  WEEKLY H I N I H U H S O I L  S"l  J  R  S  O H O I 971  J  F  clearcutting watershed A  TEMPERATURES  M  R  H  J  J  f  l  117 X  S  O  N  D  J  F  H  f  i  M  J  J  f  1173  i  S  O  N  D  J  F  I  H  f  i  117/r  87 T h i s a l t i t u d i n a l temperature g r a d i e n t i s a l s o i l l u s t r a t e d by t h e lower water t e m p e r a t u r e s r e c o r d e d a t w e i r C compared t o t h o s e r e c o r d e d downstream at weir B  ( F i g u r e 4.5).  T y p i c a l d a i l y temperature b e h a v i o u r f o r w i n t e r and summer i s shown i n F i g u r e 4.6.  D a i l y f l u c t u a t i o n s depended v e r y much on c l o u d c o v e r , b e i n g g r e a t -  e s t when t h e r e were no c l o u d s .  T h i s i s e x p e c t e d i n view o f t h e f a c t t h a t stream  temperature depends m a i n l y on incoming s o l a r r a d i a t i o n  (Brown, 1969).  f l u c t u a t i o n s tended t o be g r e a t e s t d u r i n g c l o u d l e s s days i n summer. w i n t e r , d a i l y f l u c t u a t i o n s were u s u a l l y q u i t e s m a l l  Daily During  ( l e s s t h a t 1°C) e x c e p t  d u r i n g t h e passage o f an a r c t i c f r o n t o v e r t h e r e g i o n when stream f o l l o w e d a i r t e m p e r a t u r e s , r i s i n g o r f a l l i n g by s e v e r a l degrees  temperatures  (Figure 4.7).  The streams a t Haney appear t o have s i m i l a r temperature regimes t o those a t Hubbard Brook  ( L i k e n s et at., 1970) and t o t h o s e i n t h e H.J. Andrews E x p e r i -  m e n t a l F o r e s t i n Oregon  (Rothacher et at., 1967) e x c e p t t h a t t h e Haney  streams  a r e s l i g h t l y c o o l e r i n t h e summer. E f f e c t s o f c l e a r c u t t i n g on stream  temperature  C l e a r c u t t i n g i s e x p e c t e d t o cause an i n c r e a s e i n stream  temperatures  d u r i n g t h e summer and a d e c r e a s e d u r i n g w i n t e r , t h e s e changes d e c r e a s i n g w i t h time as v e g e t a t i o n grows back, as d i s c u s s e d i n C h a p t e r 1. The  streams have n o t y e t been m o n i t o r e d d u r i n g a p o s t - t r e a t m e n t summer.  Data a r e a v a i l a b l e f o r an autumn and w i n t e r a f t e r c u t t i n g , however.  During  t h i s p e r i o d , maximum and minimum stream temperatures below b o t h c l e a r c u t s have tended t o be h i g h e r t h a n u s u a l ( F i g u r e s 4.8 and 4.9).  T h i s c a n be a t t r i b u t e d  t o ah i n c r e a s e i n t h e amount o f s o l a r r a d i a t i o n r e a c h i n g t h e streams, and t o an i n c r e a s e i n t h e energy s t o r e d i n t h e s o i l which i n c r e a s e s t h e temperature o f s o i l water, and t o a d s o r p t i o n o f energy by s l a s h i n t h e streams. b)  Soil  temperature  S o i l t e m p e r a t u r e s f o l l o w stream t e m p e r a t u r e s c l o s e l y  ( F i g u r e 4.10).  Lower  temperatures measured a t s t a t i o n s B and C a r e p r o b a b l y m a i n l y due t o h i g h e r a l t i t u d e s , b u t , i n summer, a l s o p a r t l y due t o g r e a t e r d e p t h s o f i n s u l a t i n g d u f f above t h e temperature p r o b e s , r e l a t i v e t o s t a t i o n A.  88 3.  Suspended sediment The streams at a l l three weirs were usually very c l e a r , and samples taken  during periods of steady flow, both high and low, contained no measurable suspended sediment (Table 4.4).  Although very few analyses of suspended sediment  were c a r r i e d out, i t appears that s i g n i f i c a n t concentrations only occur during the early part of a storm event when the stream i s r i s i n g .  Concentrations  tended to increase with discharge, peaking before the stream peaked, then dec l i n e d r a p i d l y to zero, well before the stream had dropped to base flow l e v e l s (Table 4.4).  Concentrations fluctuated widely, however, and consistent trends  could not be seen from the l i m i t e d data c o l l e c t e d . Most of the stream sediment, both before and a f t e r c l e a r c u t t i n g , was organic, the mineral p a r t i c l e s o f the s o i l generally being too large to be c a r r i e d great distances over short time periods. Due to the r e l a t i v e l y gentle topography of the watersheds and the l o c a t i o n of roads away from streams, suspended sediment concentrations were expected to be low, both before and a f t e r c l e a r c u t t i n g .  In addition, r e l a t i v e l y low stream  gradients and the presence of many pools caused by small debris jams which help to f i l t e r out sediment, also favoured low sediment concentrations. Table 4.4 Stream  Suspended sediment concentrations i n streams leaving the watersheds. Time and date Before c l e a r c u t t i n g  Discharge(litres/sec)  Suspended sediment concentration(mg/1)  C  2.45 3.00 3.15  p.m. p.m. p.m.  12/7/72 12/7/72 12/7/72  249 1223 553  A B c  11.15 11.30 11.50  a.m. a.m. a.m.  24/8/72 24/8/72 24/8/72  0.6 1.7 1.2  steady summer base flow  0.0 0.0 0.0  A B  5:00 5.15 5.30  p.m. p.m. p.m.  12/1/73 12/1/73 12/1/73  17 78 39  steady winter base flow  0.0 0.0 0.0  A B  C  peak discharge of the l a r g e s t recorded storm  cont.  107.0 29.5 12.0  89 T a b l e 4.4  cont.  Stream  Time 5and d a t e D u r i n g and a f t e r Clearcutting October  Suspended sediment c o n c e n t r a t i o n (mg/1) Discharg e(litres/sec)  storm  A (partially clearcut)  2.00 4.30 11.30  p.m. 12/10/73 p.m. 13/10/73 a.m. 15/10/73  4 91 9  rising falling falling  20.2 1.3 0.6  B  (fully clearcut)  1.30 6.15 5.30 12.30  p.m. p.m. p.m. p.m.  12/10/73 12/10/73 13/10/73 15/10/73  43 78 173 33  rising rising falling falling  35.2 24.2 1.3 0.8  C (undisturbed)  4.00 5.45 11.45  p.m. 12/10/73 p.m. 13/10/73 a.m. 15/10/73  40 105 17  rising falling falling  7.5 1.9 0.2  November storm A  (partially clearcut)  11.00 2.00 7.15 11.00 2.30 1.30 4.00 1.30  a.m. p.m. p.m. p.m. a.m. p.m. p.m. p.m.  27/11/73 27/11/73 27/11/73 27/11/73 28/11/73 28/11/73 28/11/73 29/11/73  38 61 120 131 118 78 67 33  rising rising rising peak falling falling falling falling  0.0 0.0 12.7 .0.6 0.4 0.0 0.0 0.0  B  (fully clearcut)  11.15 2.30 8.00 11.30 3.00 2.00 4.30 2.00  a.m. p.m. p.m. p.m. a.m. p.m. p.m. p.m.  27/11/73 27/11/73 27/11/73 27/11/73 28/11/73 28/11/73 28/11/73 29/11/73  144 273 689 694 561 290 245 100  rising rising rising peak falling falling falling falling  0.0 2.3 1.6 3.6 0.0 0.0 0.0 0.0  C (undisturbed)  12.15 2.45 7.45 11.15 3.15 2.15 4.15 2.15  p.m. p.m. p.m. p.m. a.m. p.m. p.m. p.m.  27/11/73 27/11/73 27/11/73 27/11/73 28/11/73 28/11/73 28/11/73 29/11/73  105 155 271 290 258 145 114 55  rising rising rising peak falling falling falling falling  0.0 9.3 10.3 8.8 0.4 0.0 0.0 0.0  Streamwater was a n a l y z e d f o r suspended sediment d u r i n g t h e f i r s t major storm a f t e r c l e a r c u t t i n g (October 12-14, 1973 i n T a b l e 4.4).  Shortly  after  the streams began t o r i s e , h i g h c o n c e n t r a t i o n s were found, b u t t h e s e r a p i d l y  • 90 declined.  Suspended  sediment c o n c e n t r a t i o n s i n streams l e a v i n g t h e c l e a r c u t  watersheds d u r i n g a l a t e r storm  (November 27-29, 1973  i n T a b l e 4.4)  than d u r i n g t h e O c t o b e r storm, d e s p i t e comparable d i s c h a r g e s .  were lower  This i s probably  due t o t h e tendency o f the f i r s t major autumn storm t o f l u s h o u t d e b r i s  which  has accumulated near the streams d u r i n g t h e i r low f l o w p e r i o d i n l a t e summer. Subsequent  i n c r e a s e s i n streamflow, u n l e s s t h e y a r e g r e a t e r t h a n a l l t h e p r e -  c e d i n g ones, thus e n c o u n t e r l e s s d e b r i s t o wash away. The l i m i t e d measurements made, t o g e t h e r w i t h v i s u a l o b s e r v a t i o n s , suggest t h a t c l e a r c u t t i n g has caused no major change i n suspended sediment c o n c e n t r a - . t i o n s w i t h t h e p o s s i b l e e x c e p t i o n o f the f i r s t major storms f o l l o w i n g cutting.  clear-  T h i s can be a t t r i b u t e d t o the r e l a t i v e l y g e n t l e topography, t h e ab-  sence o f p r o l o n g e d i n t e n s e r a i n f a l l , and t o t h e l a c k o f r o a d c o n s t r u c t i o n near streams. of  A l t h o u g h s e v e r a l s k i d r o a d s were used, e s p e c i a l l y i n t h e upper p o r t i o n  watershed A, t h e s e were g e n e r a l l y p a r a l l e l t o l a n d c o n t o u r s and n o t v e r y  steep.  Most o f watersheds A and B were y a r d e d u s i n g a h i g h l e a d s p a r system  ( F i g u r e 4.11).  A l t h o u g h y a r d i n g a c r o s s t h e streams o c c u r r e d  (Figure  4.11),  l a n d i n g s were l o c a t e d c l o s e t o t h e h e i g h t o f l a n d so t h a t n e a r l y a l l was u p h i l l .  Such l o g g i n g o p e r a t i o n s a r e known t o m i n i m i z e stream s e d i m e n t a t i o n  (Lantz, 1971b; U.S.  Department  o f t h e , I n t e r i o r , 1970).  c o n c e n t r a t i o n s f o l l o w i n g c l e a r c u t t i n g may the  Low  suspended  sediment  a l s o be due t o t h e f a c t t h a t many o f  f i n e p a r t i c l e s d e p o s i t e d i n t h e streams by l o g g i n g o p e r a t i o n s have remained  trapped behind logging debris The Hubbard  (Figure  4.12).  Brook s t u d y ( L i k e n s et al. , 1970)  found t h a t f o r e s t  and h e r b i c i d e a p p l i c a t i o n caused no o b v i o u s d i f f e r e n c e s i n t u r b i d i t y suspended  and d e f o r e s t e d watersheds.  different  cutting (and hence  sediment) o f stream water and t h a t measurements o f t u r b i d i t y were o f  l i t t l e v a l u e i n a s s e s s i n g t h e changes i n t h e q u a l i t y o f streamwater ed  yarding  from t h o s e a t Hubbard  and the Hubbard  from  forest-  A l t h o u g h t h e watershed ecosystems a t Haney a r e Brook and the commercial c l e a r c u t t i n g s a t Haney  Brook t r e e c u t t i n g t r e a t m e n t were q u i t e d i f f e r e n t , i t seems t h a t  F i g u r e 4.12 A.  Before  stream c h a n n e l s b e f o r e and a f t e r clearcutting  Stream B  clearcutting  Stream B  94  95 the Hubbard Brook c o n c l u s i o n s a p p l y j u s t as w e l l t o the watersheds Fredricksen  (1971) o b s e r v e d s i g n i f i c a n t i n c r e a s e s i n suspended  c o n c e n t r a t i o n s i n a stream f o l l o w i n g l o g g i n g i n Oregon. was  a t Haney. sediment  The watersheds  he  s t u d y i n g a r e much s t e e p e r t h a n t h o s e a t Haney, however, and t h e i r s o i l s are  quite different.  These  f a c t o r s , t o g e t h e r w i t h the use o f s l a s h b u r n i n g , which  f o l l o w e d c l e a r c u t t i n g i n the Oregon study and which tends t o i n c r e a s e the p o s s i b i l i t y o f e r o s i o n more than does c l e a r c u t t i n g a l o n e et al. , 1972;  (Dyrness, 1967;  Rice  Swanston and D y r n e s s , 1973), s u g g e s t s t h a t the l o g g i n g a t Haney  would have l e s s impact on stream sediment c o n c e n t r a t i o n s t h a n d i d the l o g g i n g i n Oregon.  Fredricksen  (1970) a l s o n o t e d t h a t , f o l l o w i n g c l e a r c u t t i n g , most o f  t h e f i n e sediment and n e a r l y a l l the c o a r s e sediment remained c h a n n e l t r a p p e d b e h i n d l o g g i n g d e b r i s , as was study 4.  (Figure  i n the stream  p r o b a b l y the case i n t h e p r e s e n t  4.12).  D i s s o l v e d oxygen  Seasonal behaviour The  stream water a t Haney was  ( F i g u r e 4.14).  u s u a l l y between 90% and 110%  saturated  V a l u e s below s a t u r a t i o n were most common d u r i n g the l o w e s t  f l o w p e r i o d s i n l a t e summer and e a r l y autumn when stream temperatures were a l s o a t a maximum.  However, v a l u e s below 65% s a t u r a t i o n have n o t been measured.  S u p e r s a t u r a t i o n o f d i s s o l v e d oxygen i n stream water has been f r e q u e n t l y o b s e r v e d i n many p a r t s o f the w o r l d t h e r e i n ; L i n d r o t h , 1957), km.  (e.g. L i k e n s et al. , 1970  and r e f e r e n c e s  i n c l u d i n g a t r i b u t a r y o f the P i t t r i v e r ,  north o f the study area  (Harvey and Cooper,  t u r b u l e n c e i n which gas b u b b l e s a r e pushed  1962).  T h i s may  on the a l t i t u d i n a l case streamwater  ( L i n d r o t h , 1957).  stream temperature g r a d i e n t temperatures may  be due  to  t o v a r i o u s depths i n streams, where  t h e y g i v e o f f some o f t h e i r gases t o the water, due t o i n c r e a s e d p r e s s u r e s , b e f o r e r i s i n g t o the s u r f a c e  several  hydrostatic  I t may  a l s o depend  ( L i k e n s et al. , 1970),  i n which  be e q u i l i b r a t i n g w i t h a i r temperatures more  r a p i d l y t h a n a r e d i s s o l v e d oxygen c o n c e n t r a t i o n s w i t h stream water  temperatures.  96  F i g u r e 4.13  D i s s o l v e d oxygen c o n c e n t r a t i o n s - stream A, B, and C  DISSOLVED OXYGEN CONCENTRATION  16  clearcutting A  fl = STREAM fl B = STREAM B C = STREAM C  § 12 g 101 y o  CJ  si i  in in i II in II II n u n i H i i u i i i i i n i i i i i m m i m i n i n u n m i n i m m i i i i i i i i m i i i i i n i i timi i i i i i i i i i i i n i i i i i i i i i i i i n i i i  ONDJFMRMJJflSONDJFMflMJJRSONDJFMRMJJflSONDJFMfl F i g u r e 4.14  160 j  D i s s o l v e d oxygen p e r c e n t s a t u r a t i o n - streams A, B, and C  DISSOLVED OXYGEN PERCENT SATURATION clearcuttingA  fl = STREAM fl  I  B = 5TRERM B  1  clearcuttingB  140 •• C = STREAM C 120 • 100  80 j 60  n m i i i i H i i i i i n u n m i n i n u n m i n i n u n ii  iiiiniiniuniitniiimmn4mintmnmntMmiiiiiiiiiiiiiiiiw  O N D J F M f l M J J f i S O N D J F M f l M J J H S O N D J F M f i M J J R S O N D J F M R  1970  1971  1972  1973  1974  97 As  can be  seen from F i g u r e s 4.15  and  4.16,  the time o f sampling  f e c t the measured c o n c e n t r a t i o n s and degrees o f s a t u r a t i o n . u s u a l l y o c c u r r e d between 10 a.m.  and  4 p.m.  the day  ( F i g u r e s 4.15  and  4.16).  Weekly  D i s s o l v e d oxygen  1963,  lower d u r i n g the n i g h t and h i g h e r  T h i s suggests  t h a t t h e r e was  Schmassmann,1951; Wiken, 1936).  d i u r n a l v a r i a t i o n i n pH v a l u e s photosynthetic  ( F i g u r e s 4.15  i n t h e streams was  f u r t h e r suggests  only rather s l i g h t  T h i s i s a l s o supported  The  The  and  during  some, a l b e i t processes  absence o f a pronounced  4.16)  which would o c c u r i f  during d a y l i g h t hours,  increas-  t h a t p h o t o s y n t h e t i c oxygen p r o d u c t i o n  ( L i v i n g s t o n e , 1963;  Minckley,  1963).  by t h e absence o f h i g h d i s s o l v e d oxygen c o n c e n t r a t i o n s  i n e a r l y summer when stream f l o w s and thetic activity  and  organisms took up d i s s o l v e d CC^  i n g the streamwater pH,  sampling  concentrations  s l i g h t , p r o d u c t i o n o f oxygen i n the streams by p h o t o s y n t h e t i c (Minckley,  af-  - the time when c o n c e n t r a t i o n s  degree o f s a t u r a t i o n tended t o be h i g h e s t . and d e g r e e s o f s a t u r a t i o n tended t o be  can  s h o u l d a l s o be h i g h  d i s s o l v e d oxygen b e h a v i o u r  temperatures a r e h i g h and when p h o t o s y n -  (Minckley,  1963).  o f the streams a t Haney i s a l m o s t  identical  t o t h a t a t Hubbard Brook ( L i k e n s et al. , 1970). Weisel  and N e w e l l  (1970), s t u d y i n g streams i n western Montana, found  that  d i s s o l v e d oxygen c o n c e n t r a t i o n s e x h i b i t e d a p a t t e r n s i m i l a r t o those a t Haney, but they  found  t h a t the degree o f oxygen s a t u r a t i o n was  h i g h e s t d u r i n g the  low  f l o w summer months which t h e y a t t r i b u t e d t o p h o t o s y n t h e t i c p r o d u c t i o n o f oxygen w i t h i n the streams. Moreover, they found and  they observed  found  than on d i s c h a r g e .  due  levels, and  t o changes i n water temperature.  In  t h a t d i s s o l v e d oxygen depended more on stream temperature T h e i r study streams, however, flowed  t u r b e d watersheds a t e l e v a t i o n s above 1000 f o r most o f the peak stream r u n o f f , and those a t Haney.  i n oxygen  maximum d i s s o l v e d oxygen c o n c e n t r a t i o n s i n the morning  minimum c o n c e n t r a t i o n s i n the evening a d d i t i o n , they  no n o c t u r n a l d e c r e a s e  m.  through h i g h l y d i s -  where s p r i n g snowmelt a c c o u n t e d  temperature extremes were g r e a t e r  Thus, these Montana streams a r e not r e a l l y comparable t o  than those  98 Figure  4.15(a)  D i u r n a l v a r i a t i o n i n streamwater d i s s o l v e d oxygen and pH - l a t e autumn  STREAM A D i s c h a r g e - steady a t 3.8 l i t r e s / s e c D i s s o l v e d oxygen % saturation 86 , 84  J All  80  readings ±3%  76 74  ~i  1  D i s s o l v e d oxygen 9.5 9.2  1  r  ~l  concentration  1  r  1  1  1  (mg/1)  J A l l readings ±.2 mg/1  8.8  8.4H 8.0  i  1  1  1  -i  r  1  1  1  1  r  pH  6.71  A l l readings ±.1 pH u n i t  6.6 6.5. T  1  1  ; 1  T  1  1  1  1  1  1  1  1  1  1  Stream temperature (°C) 5.2 4.8 4.4 4.0  i  1  -i  r  1800 November 5  2400  i  r 600 November 6  —i  1200 1973  99  F i g u r e 4.15(b)  D i u r n a l v a r i a t i o n i n streamwater d i s s o l v e d oxygen - l a t e autumn  STREAM B o  D i s c h a r g e - s t e a d y a t 12.4 l i t r e s / s e c D i s s o l v e d oxygen % saturation 100-r All  96H  points ±4%  92-  88~i  D i s s o l v e d oxygen 12.4,  1  1  r  concentration  -i  1  1  1  1 — — i  1  (mg/1)  A l l points ±.2 mg/1  12.011.611.2J 10.8.  T  1  1  1  r  T—  1  1  1  pH 6.8  1—  1  1  A l l points ±.1 pH u n i t  6.6-1 6.4  1  ~\  1  1  r  T  1  i  1  1  1  1  1  1  1  1  Stream temperature (°C) 4.2 -, 3.8H 3.4  1 r 1800 November 5  i — ; — i  — | — ;  2400  1——i  600 November 6  r  1200 1973  100 F i g u r e 4.15(c)  D i u r n a l v a r i a t i o n i n streamwater d i s s o l v e d oxygen - l a t e autumn  STREAM C D i s c h a r g e - steady a t 7.2 l i t r e s / s e c D i s s o l v e d oxygen % saturation 100 n  H  96  All  points ±4%  92 88  J  84  T  1  1  1  r  D i s s o l v e d oxygen c o n c e n t r a t i o n 12.8'  i  r  r  (mg/1)  12.4-  A l l points ±.2 mg/1  .12.011.611.2  1  1  1  1  r  "I  i  i  1  1  pH 6.9-,  1  - T — — I  A l l points ±.1 pH u n i t  -* *6.7H i  T  i  1—•—r  "i  I  — i  r—  1  r  Stream temperature (°C) 3.4-, 3.0-] 2.6  1  ~i  •  1  1  1800 November 5  r  ~i  24'00  1—'—i  600 November 6  1  1——i  1200 1973  101 Figure  4.16(a) . D i u r n a l v a r i a t i o n i n streamwater d i s s o l v e d oxygen and pH - e a r l y summer STREAM A  D i s s o l v e d oxygen 96^  % saturation  94 92 -|  All  points ±4%  90 88  ~i  1  1  1  r  D i s s o l v e d oxygen c o n c e n t r a t i o n 10.0'  1  1  1  1  1  1  (mg/1)  9.8 9.6 A l l points ±.2 mg/1  9.4 9.2  ~i  1  1  1  -i  r  1  1  1  —I  1  i  pH 7.0-1 6.9  11 p o i n t s ±.1 pH u n i t  6.8  T  1  1  Stream d i s c h a r g e .1.4,  1  r  T  1  1  1  1  1  1  1  1  1  1  1  1  r  1  1  (litres/sec)  1.0. i—:—i  1  Stream temperature  1  T  r  (^C)  11.1" 10.91 10.7  -T  r  1800 June 24  1 2400  r  "i  600 June 25  T  1200 1972  102 F i g u r e 4.16(b)  D i u r n a l v a r i a t i o n i n streamwater d i s s o l v e d oxygen and pH - e a r l y summer  STREAM B D i s s o l v e d oxygen % s a t u r a t i o n 108 - i 104 A 100 J  All  points ±4%  96 A  i  r  i  D i s s o l v e d oxygen c o n c e n t r a t i o n 11.2 _,  1  1  1  1  r  (mg/1)  10.8 10.4 -  A l l points ±.2 mg/1  10.0 1  ~t  1  r  -i  1  1—:—r  1  pH 7.0 -,  r  A l l points ±.1 pH u n i t  6.9 i  1  Stream d i s c h a r g e 10.0 ~]  1  r  T—  1  1  r  "i  1  1  1  1  1  1—:—i  ~i  r  (litres/sec)  5.0 A 2.0  T  1  1  1  r  r~  1  1  1  r  1  r  Stream temperature (°C) 10.4 -, 10.0 H 9.6  1  1  1  1800 June 24  1  2400 i4c  1  600 June 25  1200  I n s u f f i c i e n t measurements were made o f d i s s o l v e d oxygen and pH on stream C t o p e r m i t d i u r n a l t r e n d s t o become apparent.  1972  103 at Haney. V a r i a t i o n with  discharge  Dissolved oxygen concentrations and, to a l e s s e r extent, degrees of saturat i o n , increased with discharge r e l a t i o n s h i p may be complicated  (Figures 4.17, 4.18, and 4.19).  However, the  by temperature e f f e c t s , since the lowest flows  occurred during l a t e summer when stream temperatures were highest. V a r i a t i o n between streams Dissolved oxygen concentrations i n stream A tended to be lower than those i n streams B and C (Figure 4.13).  This may be p a r t l y due to the f a c t that,  although the average stream gradients are s i m i l a r , immediately upstream of the sampling points, stream A had a very low gradient with l i t t l e  turbulence  whereas immediately upstream of sampling points B and C, the stream dropped more r a p i d l y with considerable turbulence.  I t may also be p a r t l y due to the  f a c t that stream A tended t o be s l i g h t l y warmer than streams B and C as d i s cussed above, and i s also smaller, making i t s dissolved oxygen concentrations more e a s i l y lowered by inputs of organic materials. E f f e c t s of c l e a r c u t t i n g I t i s too soon t o detect any s i g n i f i c a n t e f f e c t of c l e a r c u t t i n g on d i s solved oxygen l e v e l s i n streams A and B as the e f f e c t s are only l i k e l y t o be s i g n i f i c a n t during the summer and early autumn.  This i s indicated by the be-  haviour of dissolved oxygen i n streams D and E following c l e a r c u t t i n g (Figures 4.20 and 4.21).  During the cooler and wetter months, dissolved oxygen concen-  trations i n these streams remained close t o 100% saturation, even a f t e r c l e a r cutting, whereas during the warmer and d r i e r months, dissolved oxygen concentrations dropped spectacularly following c l e a r c u t t i n g , often to l e s s than 5 mg/litre and 50% saturation.  Dissolved oxygen concentrations a l s o exhibited  much greater f l u c t u a t i o n s i n response to discharge a f t e r c l e a r c u t t i n g than before (Figures 4.20 and 4.21).  Clearcutting appears to have lowered the s t a b i l i t y  of the stream ecosystem with respect to dissolved oxygen.  Figure 4.17  Relationships between streamwater dissolved oxygen concentrations and discharge.  DISSOLVED OXYGEN VERSUS DISCHARGE. STREAM A . BLfonE C I E W C U T I I K ; I fifTER CLLRBCUrilNG  Y = 9.570 + 2.1341ogX (r = .75)  — i —  s.s  13.0  —1 19.5  1 36.0  32.5  39.0  0I5CHARGE [LITRES/SEC) DISSOLVED OXYGEN VERSUS DISCHARGE. STREAM B  —I 45.5  . BEFORE CIEFBCUTUKS I RFTEH  CLERKajTUHS  Y = 10.56 + 1.3481ogX (r = .55)  a.o  •  i *6.0  ^ 52.0  1 78.0  1 104.0  1  1  130.0  156  DISCHARGE (LITRES/SEC) DISSOLVED OXYGEN VERSUS DISCHARGE. STREAM C .  0  208.0  234.0  -1' 2E0  Y = 10.80 + 1.1421ogX (r = .58)  0.0  — t — n.o  ~ i — 23.0  13.0  44.0  SR..O  60  0  DISCHARGE (LITRES/SEC) '  —r— 88.0  B9.0  Regressions are f o r "before c l e a r c u t t i n g " data only.  —1  1)0  105 Figure 4.18. Relationships between streamwater dissolved oxygen percent saturations and discharge. DISSOLVED  OXYGEN PERCENT  SATURATION  VERSUS D I S C H A R G E .  STREAM A  . BEFORE ClEflRCUniW I WICR CltWEUITlNS  Y = 95.9124 - 6.2468C-) (r = .47) X  1  1  1  1  1  1  1  6.3  13.0  19.5  25.0  32.5  39.0  "S.5  DISCHARGE ( L I T R t S / S E C ) D I S S O L V E D OXYGEN PERCENT SATURATION VERSUS D I S C H A R G E .  1— 52.0  STREAM 8  . BEFORE aEPRCJTTING  I RFTER O-ERSCUTTING  7B.0  104.0  130.0  155.0  —1  DISCHARGE ( L I T R E S / S E C ! D1SSOLVE0 OXYGEN PERCENT SATURATION VERSUS D I S C H A R G E .  —I  182.0  STREAM C  234.0  280.0  UJ  0.0  —I—  u.o  —1 33.0  1 14.(1  DISCHARGE  1—  W B  1— 66.0  — l — ea.o  — l — 03.0  110.0  (L U R L S / S E C !  Regression i s f o r "before c l e a r c u t t i n g " data only, r e l a t i o n s h i p s were found f o r streams B and C.  No s i g n i f i c a n t  106 F i g u r e 4.19(a)  Streamwater d i s s o l v e d oxygen d u r i n g a storm event (27-29 November, 1973)  STREAM A  D i s s o l v e d oxygen c o n c e n t r a t i o n  (mg/1)  Figure  4.19(b)  Streamwater d i s s o l v e d oxygen d u r i n g (27-29 November, 1973)  a storm event  STREAM B  D i s s o l v e d oxygen c o n c e n t r a t i o n 13.5"  (mg/1)  A l l points ±.2 mg/1  13.0 12.5  T  ~i  r  D i s s o l v e d oxygen % s a t u r a t i o n 105-  All  95  -i Stream d i s c h a r g e 1000-i 500  -i  r  -|  r  J  Stream temperature (°C) 4.5  r  (litres/sec)  100 10-1 0  r  points ±4%  108 F i g u r e 4.19(c)  Streamwater d i s s o l v e d oxygen d u r i n g a storm event (27-29 November, 1973)  STREAM C  D i s s o l v e d oxygen c o n c e n t r a t i o n 15.0-  (mg/1) A l l points ±.2 mg/1  14.04 13.0-  T  T  r  D i s s o l v e d oxygen % s a t u r a t i o n 105 n 95  -*  A l l points ±4%  H -i  Stream d i s c h a r g e 300-  (litres/sec)  100-  Stream t e m p e r a t u r e 4.0 3.0 •  (°c)  r-  109  F i g u r e 4.20  20  DISSOLVED OXYGEN CONCENTRATION  T  c  |  16-  E  12-  CH  81  LU CJ  4-  CE  D i s s o l v e d oxvqen c o n c e n t r a t i o n s - streams'D and E  D E  STREAM C STREAM D  F e l  STREAM E  ,  l i n 9  |  Y  a  r  p  9  I  ZZL  o Q  liiiiiimtuiMtiiifiiiicsiifimiiIIIIIPIf«ini«itmi<tiiniitiitiiimitiniMHIIHIIIMMtiimimiii 11111111111111111111  QNDJFMRMJJRSONDJFMHMJJRSONDJFMflMJJflSONDJFMR F i g u r e 4.21  140 j 120 ••  D i s s o l v e d oxygen p e r c e n t s a t u r a t i o n - streams D and E  DISSOLVED OXYGEN PERCENT SATURATION C = STREAM C D = STREAM D E = STRERM E  ,  100 80 •• 60 •• 40 • 20 • 0 QNDJFMHMJJRSONDJFMRMJJRSONDJFMRMJJRSQNDJFMR  1970  1971  1972  1973  1974  110 The  odour o f hydrogen s u l p h i d e f r e q u e n t l y  d e t e c t e d near streams D and  a f t e r c l e a r c u t t i n g suggested the  o c c u r r e n c e of a n a e r o b i c d e c o m p o s i t i o n o f  s l a s h d e p o s i t e d i n the  Such d e c o m p o s i t i o n i s i n d i c a t i v e o f  a b l e b i o l o g i c a l and  streams.  c h e m i c a l oxygen demands w i t h r e s u l t i n g low  E the  consider-  dissolved  oxygen  concentrations. Similar  low  dissolved  oxygen c o n c e n t r a t i o n s a f t e r l o g g i n g  s e r v e d i n the A l s e a b a s i n  i n Oregon by H a l l and  removal o f s l a s h from streams r a i s e d the oxygen b u t  had  little  Lantz  (1969).  l e v e l s o f the  e f f e c t on i n t r a g r a v e l d i s s o l v e d  c u t t i n g but  none have been o b s e r v e d s i n c e .  evidence that  been c o n s i s t e n t l y  and  g e n e r a l w e l l - b e i n g o f t r o u t and  t e e t o the ulations  lower t h a n 6 m g / l i t r e  S e c r e t a r y of the  B,  t i o n of r e s i d e n t  and  I n t e r i o r , 1972)  cutthroat  trout,  f o r e s t c u t t i n g and  (Likens et  al.,  1970)  maintain high dissolved  This,  from the  the  After  trout.  clear-  conclusive  Technical  e a r l y autumn f o r good growth  A d v i s o r y Committhe  o b s e r v e d oxygen  i n length.  d a t a have not  concen-  t h e r e was  f i s h pop-  reduction. a popula-  F i s h surverys of T.G.  Northcote  y e t been p r o c e s s e d .  i n g r e a t e r stream d i s c h a r g e s which h e l p e d  oxygen c o n c e n t r a t i o n s d u r i n g the attempt was  summer months.  made t o keep s l a s h out  to In  oxygen  (G.E.  commercial c l e a r c u t t i n g , where l a r g e  the  of  t o g e t h e r w i t h c o n s i d e r a b l e stream t u r b u l e n c e , i s c o n s i d e r e d  have m a i n t a i n e d h i g h l e v e l s o f d i s s o l v e d cation).  dissolved  a p p l i c a t i o n experiment a t Hubbard Brook  Hubbard Brook experiment, a d e l i b e r a t e streams.  level required  a f t e r c l e a r c u t t i n g , by Dr.  herbicide  resulted  E p r i o r to  so i t i s l i k e l y t h a t  5 t o 15 cm.  o f t h e Z o o l o g y Department, U.B.C, b u t  low  o f salmon and  summer and  C s u p p o r t e d no anadromous f i s h b u t  t h e s e streams were made b e f o r e and  The  (the  salmon, N a t i o n a l  i n t h e s e streams have s u f f e r e d  Streams A,  E i n the  that  dissolved  o f reduced oxygen l e v e l s , the  oxygen i n streams D and  has  The  A l t h o u g h t h e r e i s no  t h e i r absence i s a f u n c t i o n  t r a t i o n of d i s s o l v e d  water  oxygen.  t r o u t were o b s e r v e d i n streams D and  ob-  They found  surface  oxygen c o n c e n t r a t i o n s were found t o cause h i g h m o r t a l i t y Small cutthroat  have been  to  L i k e n s : P e r s o n a l communiamounts o f s l a s h  inevitably  Ill  end up i n streams, i t seems that, despite increased flows, the b i o l o g i c a l and chemical oxygen demand of the decaying slash w i l l lower dissolved oxygen concentrations i n streams. 5.  pH  Seasonal behaviour The streams at Haney were characterized by neutral to s l i g h t l y a c i d i c water, with pH usually ranging from 6.5 to 7.2.  Although weekly fluctuations  were considerable, a trend towards higher pH i n the summer and lower pH i n the winter was discernable (Figure 4.22). Similar trends have been found at Hubbard Brook (Fisher et al.,  1968;  Likens et at., 1970).and i n western Montana (Weisel and Newell, 1970)  where  they have generally been a t t r i b u t e d to variations i n discharge, pH decreasing with increasing discharge (Johnson et at., 1969). The decrease i n pH i n autumn was probably due mainly to d i l u t i o n by more a c i d i c t h r o u g h f a l l and s o i l waters.  However, i t may have been p a r t l y due to  increased l i t t e r f a l l which deposits large amounts of organic material i n the streams.  Leached constituents and the decomposition products of l e a f  litter  have been shown to s i g n i f i c a n t l y a f f e c t streamwater pH i n autumn (Minckley, 1963;  Slack and F e l t z , 1968)  and may  do so to some extent at Haney.  streams there were surrounded by deciduous species such as Rubus Alnus rubra,  Oplopanax horridus,  and Vaccinium  The spectabilis,  sp. and large amounts of leaf  l i t t e r have been observed on and i n the streams during autumn. V a r i a t i o n with discharge pH decreased with increasing discharge (Figures 4.23  and 4.24)  as i t did  i n streams i n Oregon (Rothacher et al., 1967), Utah (Johnston and Doty, 1972), and New  Hampshire (Johnson et at., 1969), accounting f o r the weekly f l u c t u a t i o n s .  V a r i a t i o n between streams There were no s i g n i f i c a n t differences i n pH values between streams (Figure 4.22) .  F i g u r e 4.22  8T  A  =  S T R E A M fl  B  =  STREAM  B  •C. =  STREAM  C  Streamwater pH - streams A , B, and C  P  H clearcutting-  clearcutting-  7.6-  1  B  1  7.26.86.4g  ti11nu1111111111iiii111  ii  iiiiiiiiiiiiiiiiiiiiiiinliiiiiii mini min minimi  iiiiiiiilinmn  i  ONDJFMRMJJflSONDJFMflMJJflSO'NDJFMflMJJflSONDJFMfl  1970  1971  1972  19.73  1974  Figure 4.23. PH  Relationships between streamwater pH and discharge.  pH VERSUS DISCHARGE. STREAM H . etfjit au;ru!ii.», 0 WTER CLERft'uniNG  6.973 - 0.24521ogX (r = .60)-  0.0  PH'  0.0  — i — 6.S  I  13.0  ~1  19.5  1  25.0  1  32.5  1  39.0  —I  «.5  —I  t  52.0  65.0  ST CRHEAARMGEBILITRES/SEC! pH VERSUS DI5CHARGE.DIS . BEFORE a.E?fiamiiit; 0 RFTER CURSOJTT1SG Y = 7.101 - 0.27421ogX (r = .67)  T26.0  52.0  —n  1  78.0  104.0  1  130.0  DISCHARGE (LITRES/SEC) pH VERSUS DISCHARGE. STREAM C  1  1S6.0  -1 182.0  -1 208.0  -1  234.0  1  260.0  Y = 7.019 - 0.27451ogX (r = .80)  0.0  i II.0  i 22.0  1 1 1— <M.0 Vill GC.O DISCHARGE (LITRES/SEXI  i 33.0  77.0  en.o  Regressions are f o r "before c l e a r c u t t i n g " data only.  no o  no. o  114 Figure 4.24  Streamwater pH during a storm event (27-29 November, 1973)  STREAM A pH 6.41  T  STREAM C  1 27  1  1  1  1  1  j  28  (undisturbed)  A l l points ±.1 pH u n i t  1  1 29  r  F i g u r e 4.25. Streamwater pH - streams D and E  8  7.5  PH  G = STREAM C D = STREAM D  Felling  Yarding  E = STREAM E  7  6.565.5iii aiiiai igjffgifiijfg iiiiiii iitiBfftiiiitfiifiififiiii ifinjitimi ifiiifiiiini iiifiiniitit iiftffjiniiniiiitiniifti minim  ONDJFMflMJJflSONDJFMflMJJflSONDJFMflMJJflSONDJFMfl  1970-  1971  1972  1973  1974  116 Effects of clearcutting Clearcutting  has lowered  4.25; T a b l e 4.5).  streamwater pH s l i g h t l y  ( F i g u r e s 4.22 and  These d e c r e a s e s were g e n e r a l l y s t a t i s t i c a l l y s i g n i f i c a n t  (Appendix X ) . The d e c r e a s e s  r e s u l t from a combination  o f the f o l l o w i n g  factors:  1.  I n c r e a s e d stream d i s c h a r g e s f o l l o w i n g  2.  L e a c h i n g o f i o n i z a b l e o r g a n i c a c i d s from t h e s l a s h .  3.  I n c r e a s e d carbon d i o x i d e p r o d u c t i o n r e s u l t i n g from enhanced o f decomposer  T a b l e 4.5  clearcutting.  organisms.  Average pH v a l u e s o f streams b e f o r e and a f t e r after  before Stream A 6.7(.2) C o n t r o l (C) 6 . 6 ( . l ) before Stream D 6.7(.2) C o n t r o l (C) 7.0(.2) Standard  activity  clearcutting.  before  6.4(.l) 6.5(.l)  Stream B 6.7(.2) C o n t r o l (C) 6.7(.2)  after(1)  after(2)  6.4(.3) 6.8(.2)  6.6(.2) 6.9(.2)  before Stream E 6.8(.2) C o n t r o l (C) 7.0(.2)  after 6.4(.2) 6.6(.2) a f t e r (1) a f t e r ( 2 ) 6.5(.3) 6.8(.2)  6.8(.2) 6.9(.2)  d e v i a t i o n s are given i n parentheses.  Values are f o r the periods: A  -  November 1, 1972 t o A p r i l 1, 1973 b e f o r e c l e a r c u t t i n g November 1, 1973 t o A p r i l 1, 1974 a f t e r c l e a r c u t t i n g  B  -  October October  D,E -  April April April  1, 1972 t o A p r i l 1, 1973 b e f o r e c l e a r c u t t i n g 1, 1973 t o A p r i l 1, 1974 a f t e r c l e a r c u t t i n g  1, 1971 t o November 1, 1971 b e f o r e c l e a r c u t t i n g 1, 1972 t o November 1, 1972 a f t e r c l e a r c u t t i n g - y e a r 1 1, 1973 t o November 1, 1973 a f t e r c l e a r c u t t i n g - y e a r 2  A s i m i l a r decrease study f o l l o w i n g 6.  Electrical  Seasonal  i n streamwater pH was o b s e r v e d  i n t h e Hubbard Brook  f o r e s t c u t t i n g and h e r b i c i d e a p p l i c a t i o n  ( L i k e n s et al. , 1970).  conductivity  behaviour  E l e c t r i c a l conductivity  o f t h e streamwatdr underwent pronounced  seasonal  f l u c t u a t i o n s w i t h minimum v a l u e s i n w i n t e r and maximum v a l u e s i n l a t e summer and e a r l y autumn.  The v a l u e s f l u c t u a t e d  micromhos/cm a t 25°C.  from 10 t o 30 around a mean o f 20  117 S i m i l a r seasonal  b e h a v i o u r i n e l e c t r i c a l c o n d u c t i v i t y has (Rothacher et  streams i n c o a s t a l Oregon (Kopperdahl et  al.  ,. 1971) .  i d s were r e p o r t e d ,  but  v a r i e s d i r e c t l y with,  al.  , 1967)  and  In b o t h c a s e s o n l y v a l u e s  coastal California for total dissolved  e l e c t r i c a l conductivity i s closely related to, t o t a l dissolved s o l i d s concentrations  streams a t Hubbard Brook and  al.,  1969;  Likens  et  al.,  (Hem,  P i e r c e et  1970).  al.  9 micromhos/cm; f o r the V a r i a t i o n with  For  s i x o f the  seventh i t was  1970a; L i v i n g s t o n e ,  streams the  range was  Hampshire  l e s s than  26 micromhos/cm.  1963;  (Figures  been e s t a b l i s h e d f o r many streams  Stottlemyer  and  Ralston,  4.27  (Keller,  1970).  a s i n g l e storm event, the e l e c t r i c a l c o n d u c t i v i t y f o r a g i v e n  charge i s h i g h e r  on  the r i s i n g limb o f the hydrograph than on the  w i t h the minimum c o n d u c t i v i t y o c c u r r i n g a f t e r the stream has 4.28).  electri-  discharge  4.28); a c o n d i t i o n t h a t has  Within  The  (1972) quote ranges o f  E l e c t r i c a l c o n d u c t i v i t y decreased with i n c r e a s i n g discharge and  and  v a r i a t i o n (Bormann  o f e l e c t r i c a l c o n d u c t i v i t y measured i n seven d i f f e r e n t streams i n New over an e i g h t month p e r i o d .  sol-  1970).  nearby a r e a s seem t o have r a t h e r u n i f o r m  c a l c o n d u c t i v i t i e s which undergo l i t t l e d a i l y o r s e a s o n a l et  been found f o r  T h i s may  be due  dis-  falling  peaked  limb,  (Figure  t o the tendency o f the e a r l i e r port-ion o f waters con-  t r i b u t i n g t o stream stormflow to f l u s h c h e m i c a l s from the ecosystem, becoming enriched  i n them r e l a t i v e t o the  may  have r e l a t i v e l y g r e a t e r  and  r e l a t i v e l y smaller  later portion.  In a d d i t i o n , the l a t e r  c o n t r i b u t i o n s from l o w - c o n d u c t i v i t y  c o n t r i b u t i o n s from h i g h - c o n d u c t i v i t y  portion  ground water  surface  runoff  and  throughfall. McColl  (1972; 1973a) s t u d i e d the c h e m i s t r y o f water p a s s i n g  f o r e s t f l o o r and m i n e r a l Washington. general  s o i l A horizon of a Douglas-fir  His data i n d i c a t e d that, regardless  d e c l i n e i n e l e c t r i c a l c o n d u c t i v i t y across  e a r l i e r p o r t i o n o f the  through  f o r e s t i n western  o f f l o w r a t e , t h e r e was a storm f r o n t w i t h  storm f r o n t water h a v i n g a h i g h e r  the  a  the  c o n d u c t i v i t y than  the  F i g u r e 4.26  40  ELECTRICAL CONDUCT I V I U .  clearcutting-  T  32-  Streamwater e l e c t r i c a l c o n d u c t i v i t y - streams A, B, and C  STREAM  A  B  STREAM  B  C  STREAM  C  clearcutting-  CH  LU Q_ D  JZ  o  Ct  24LO CM  cr  168 0  J J f' J'»^ 11: r i T i f r) 111 J J r r i  i f > f f 11 i <) J1111111J: 11 < J f 1111111 > 11 J J i f 11 r i J 1111 J 11 f t f 11 f 111 a 11 j j ; i > 11111 r > j 11 [ 1111 (11 T 111 J 1111) r i  ONDJFMRMJJflSONDJFMflMJJflSONDJFMRMJJRSONDJFMR  1970  1971  1972  1973  1974 co  119 Figure 4.27  Relationship's between streamwater e l e c t r i c a l conductivity and discharge.  ELECTRICAL CUNli'oCnviTT VERSUS DISCHARGE.  STREAM fl  . tira:!. CLtfrcuiTiNS I fif ICR CLlBiXUIIIdS  5.2981ogX .75)  o  u 5  in  o.o  6.5  13.0  19.S  25.0  37.5  39.0  58.5  DISCHARGE (LITRES/SEC) ELECTRICRL CONDUCTIVITY VERSUS DISCHARGE STREAM 8  —1 £5.0  . stfORE atflRcaniw: t RFTES aESfiOJTlKG  Y = 24.81 - 4.7881ogX (r = .75)  (0  78.0  u  •H  U 4J O <0  104.0  130.0  156.0  208.0  0ISCHASGE (LITRES/SEC) ELECTRICAL CONDUCTIVITY VERSUS DISCHARGE. STREAM C  rH  W  Y = 26.57 - 5.9811ogX (r = .76)  - 1 — u.o  i 3J.0  i 44 0  1  0  1—  f.fi.O  DISCHARGE ILI IRES/SEC)  77.0  -1  60.0  Regressions are f o r "before clearcutting." data only.  250.0  120 Figure 4.28  Streamwater e l e c t r i c a l conductivity' during a storm event (27-29 November, 1973)  Conductivity  (micromhos/cm at 25°C)  STREAM A  17.0-1  cond  Conductivity 17. CH  (micromhos/cm at 25°C)  Discharge (litres/sec) ,-150  STREAM B  16.516. a 15.515. a  Discharge (litres/sec) 1000 -  14.5-  h500  14.04 27 Conductivity 15.5T  28  (micromhos/cm at 25°C)  29 STREAM C (undisturbed)  Discharge (litres/sec) r500 300 hlOO  A l l points ±.5 micromhos/cm at 25°C  121 later  portion.  Windsor  (1969) s t u d i e d phosphorus,  t h r o u g h f a l l , stemflow,  i r o n , aluminium,  and s i l i c o n i n  f o r e s t f l o o r l e a c h a t e s , and s i x m i n e r a l s o i l l e a c h a t e s  at  d i f f e r e n t depths i n t h e same a r e a as M c C o l l .  of  t h e ecosystem  sampled,  phosphorus,  He found t h a t a t each  i r o n , and aluminium  level  c o n c e n t r a t i o n s were  h i g h e s t a t the s t a r t o f m o i s t u r e f l o w a t t h a t l e v e l and d e c r e a s e d w i t h t i m e . T h i s r e f l e c t e d an i n i t i a l f l u s h i n g away o f the c h e m i c a l s which had b u i l t in  a l e a c h a b l e form d u r i n g d r y p e r i o d s .  to  d e c r e a s e w i t h time as m o i s t u r e f l o w c o n t i n u e d , b u t f l u c t u a t e d somewhat, un-  l i k e the o t h e r compounds.  S i l i c o n concentrations also  up  tended  Some o f t h i s s o i l water, p l u s t h r o u g h f a l l and  stem-  f l o w , would c o n t r i b u t e t o stream stormflow so b o t h o f t h e s e s t u d i e s s u p p o r t the  i d e a t h a t the e a r l i e r p o r t i o n o f the water c o n t r i b u t i n g t o stream  f l o w i s e n r i c h e d i n c h e m i c a l s , and hence has a h i g h e r e l e c t r i c a l t h a n the l a t e r  conductivity,  portion.  V a r i a t i o n between In  storm-  streams  t h e u n d i s t u r b e d s t a t e , stream C g e n e r a l l y had a h i g h e r e l e c t r i c a l  d u c t i v i t y t h a n stream A, w i t h stream B the lowest  ( F i g u r e 4.26).  con-  S i n c e B and  C a r e the same stream w i t h s t a t i o n B downstream from s t a t i o n C, and the d i s s o l v e d c o n t e n t o f streamwater 1963), B was  t e n d s t o i n c r e a s e from s o u r c e t o mouth  (Livingstone,  e x p e c t e d t o have a h i g h e r e l e c t r i c a l c o n d u c t i v i t y t h a n C.  Between sampling s t a t i o n s B and C are f o u r t r i b u t a r i e s , two o f which  had  e l e c t r i c a l c o n d u c t i v i t i e s g r e a t e r than t h a t o f B, and one o f the o t h e r s had e l e c t r i c a l c o n d u c t i v i t y comparable  to that of B  ( T a b l e 4.6).  an  T h i s a l s o suggests  t h a t s t a t i o n B s h o u l d have had a g r e a t e r e l e c t r i c a l c o n d u c t i v i t y t h a n i t d i d . The f a c t t h a t s t a t i o n B u s u a l l y had a lower e l e c t r i c a l c o n d u c t i v i t y t h a n t i o n C may  be due  t o i n f l o w of s u b s u r f a c e s o i l  seepage w a t e r s .  Watershed  staB had  a more mature f o r e s t c o v e r t h a n d i d watershed C so t h a t s o i l d r a i n a g e waters i n watershed  B may  have c o n t a i n e d l e s s d i s s o l v e d s u b s t a n c e s t h a n d i d s o i l d r a i n a g e  122 Table 4.6. E l e c t r i c a l conductivity of stations B and C and.four.tributaries. sampling station  I  (.. weir  V 4\ ]  \  l\  E l e c t r i c a l conductivity (Vtmho/cm at 25°C) -25/4/73 17/5/73  C 20.2  21.3  1  34.8  35.7  2  21.4  23.4  3  17.4  17.9  4  20.2  21.0  weir C  21.0  23.1  weir B tributary  , 2  weir B waters i n watershed C. 1)  observations  This i s supported by: of water seeping from the s o i l i n streambanks into the  streams; 2)  analysis of s o i l seepage waters i n watershed B which showed that they u s u a l l y had s i g n i f i c a n t l y  lower e l e c t r i c a l c o n d u c t i v i t i e s than d i d  the streamwater, as discussed i n the following chapter; and 3)  unpublished data of Klinka (Table 4.7) which show, f o r the same b i o geocoenosis i n the U.B.C. Research Forest, a decline i n s o i l groundwater e l e c t r i c a l conductivity as the surface vegetation becomes more mature.  Another possible explanation  f o r the r e l a t i v e l y low e l e c t r i c a l  i t y of s t a t i o n B i s that ions may be l o s t from s o l u t i o n by adsorption  conductivonto  small p a r t i c l e s of organic or mineral materials, or by uptake by aquatic organisms.  V i s u a l observations  suggest that there were no obvious differences be-  tween the stream bed of watershed B and that of watershed C.  However, the d i f f e r -  ences i n e l e c t r i c a l c o n d u c t i v i t i e s were only s l i g h t and could be due to undetectable v i s u a l differences i n the composition of the streambeds.  123 T a b l e 4.7  E l e c t r i c a l c o n d u c t i v i t y o f subsurface s o i l  seepage water i n P o l y -  s t i c h u m - T h u j a p l i c a t a ecosystems o f d i f f e r e n t ages i n t h e U.B.C. Research Present  Forest.* mean e l e c t r i c a l c o n d u c t i v i t y (no. o f samples) ymho/cm a t 25°C  cover  mature f o r e s t  21.0  (12)  immature f o r e s t  31.8  (4)  u n d i s t u r b e d c u t - o v e r and p l a n t a t i o n s ( l i t t l e exposure of mineral s o i l )  41.9  (4)  d i s t u r b e d c u t - o v e r and p l a n t a t i o n s (much exposure o f mineral s o i l )  37.4  (6)  * U n p u b l i s h e d d a t a o f K. K l i n k a , Graduate S t u d e n t , F a c u l t y o f F o r e s t r y , U n i v e r s i t y o f B r i t i s h Columbia.  Differences  i n maturity  of vegetative  i n p u t s may a c c o u n t f o r t h e h i g h e r  cover o r i n g e o l o g i c a l weathering  e l e c t r i c a l c o n d u c t i v i t y o f stream A r e l a t i v e  t o stream B. Electrical  c o n d u c t i v i t y and sums o f i o n s  E l e c t r i c a l c o n d u c t i v i t y was c l o s e l y r e l a t e d t o t h e sum o f t h e c o n c e n t r a t i o n s o f t h e f o u r major c a t i o n s i n t h e streamwater: - c a l c i u m , and  potassium  bicarbonate,  sodium, magnesium,  ( F i g u r e 4.29) - as w e l l as t h a t o f t h e t h r e e major a n i o n s sulphate,  and c h l o r i d e  ( F i g u r e 4.30).  This i n d i c a t e s that reason-  a b l e e s t i m a t e s o f t o t a l c a t i o n s o r t o t a l a n i o n s i n t h e streamwater may be obt a i n e d from measurements o f e l e c t r i c a l c o n d u c t i v i t y  alone.  However, as i n d i c a t e d i n T a b l e 4.8, t h e c a t i o n i c sum i s i n v a r i a b l y l e s s than t h e a n i o n i c  sum i n d i c a t i n g t h a t t h e a n a l y s e s  cations or overestimating  anions.  o f s i l i c a t e , phosphate, s u l p h a t e , of calcium  With r e s p e c t  are e i t h e r underestimating  t o the c a t i o n s , the presence  and aluminium can lower t h e c o n c e n t r a t i o n s  and magnesium d e t e r m i n e d by atomic a b s o r p t i o n  spectrophotometry  124 Figure 4.29. Relationships between e l e c t r i c a l conductivity and the sum of potassium, sodium, magnesium and calcium concentrations. ELECTRICAL CONDUCTIVITY RELATED TO THE SUM OF THE 4 MAJOR CUT IONS. STREAM A.  . BEFOJE CU'.fflluniNG i nno) UFWiT.umuG m  CM CJ  o X 3T.  Y • 10.17 « J.420X (r - .77)  Or-"-  CK CJ  t—  I 0.5  1 . 1.0  1 1 1 1 1 1 1 1.5 2.0 2.5 3.0 3.5 4.0 4.5 NA*K'MG«CA CONCENTRATIONS IMG/L) ELECTRICAL CONDUCTIVITY RELATED TO THE SUM OF THE A MAJOR CATIONS. STREAM B.  1 SO  . BEFORE CLEFKCUT11N5 I AFTER CLEfR iCUTTJNG .CJS-  in  CM o X  T " 8.144 • 4.216X (r - .79)  sr. a  CJr--  0.0  I 0.5  I 1.0  1 1 1 1 1.5 2.0 2.5 3.0 NA*K-»MG+CA CONCENTRATIONS (MG/L)  1 3.5  1 40  -1— 4.5  ELECTRICAL CONDUCTIVITY RELATED TO THE SUM OF THE 4 MAJOR CATIONS. STREAM C.  in  CM CJ X  5.04'i « 4 . 7 4 M C (r • .91)  a;"  "•0  I 0.5  I 1.0  1 1 1 1 1.5 2.0 2.5 1.11 NA-fK + Hd+CA CONCENTRnriONS ING/L)  1 j.S  1 4.0  1 4 5  ~1 5.0  125 Figure  4.30.  R e l a t i o n s h i p s between  electrical  conductivity  and t h e sum o f b i c a r b o n a t e , s u l p h a t e , and c h l o r i d e  concentrations.  ELECTR1CRL CONDUCTIVITY RELATED TO THE SUM OF THE 3 MAJOR ANIONS. . BEFORE CIEBRCUTUNG  STREAM fl.  '  I AFTER CLtRNCUITlNG  •  in  CM  C3JC™  If - 9.239 + 1.020X lr - .82)  X  o CJ _J  do C Jr-' i—i cj  0.0  1 2.5  1 5.0  1 7.5  1 10.0  HC03*S04+CL  1 12.5  1 15.0  1 17.5  CONCENTRATIONS IMG/LI  20.0  ~I  22.5  25.0  ELECTRICAL CONDUCTIVITY RELATED TO THE SUM OF THE 3 MAJOR ANIONS. STREAM B. . BEFORE CLEARCUTTING I RfTfJ) CLEflHOimNG  in  CM Y - 8.739 + 1.087X (r - .83)  £  O gJ C CJror  CJ 0.0  1—  2.5  -1 5.0  1 7.5  1 10.0  HC03»S04-CL  1 12.5  1 1S.0  1 — 17.5  CONCENTRATIONS IMG/L)  -1— 20.0  -1 22.5  25.0  ELECTRICAL CONDUCTIVITY RELATED TO THE SUM OF THE 3 MAJOR ANIONS. STRERM C.  in  '» - 5.995 • 1.280X (r - .95)  CJ O 5* ci  g  0.0  ~~1 2.S  1  HC03*SCM  "T"  1  10.0 IP.5 15.1) >CL CONCENTRATIONS IMG/L)  17.5  —1 20.0  22.'  I 2!i.O  126 T a b l e 4.8  I o n i c sums from streamwater  Sample  analyses  C a t i o n i c sum (meq/1) A n i o n i c sum + 2+ + [ C l + HC0 fNa + Mg + K + 2 + 3 + 2 + Ca" + Fe Mn + N0 + H W + 3+ + NH. + A l + H (from 4 pH)] 3  +  11 M  7/9/72  fl If  25/1/73  ft tl  25/4/73 II II  28/11/73 II II  (David, 1960).  4  + SO^ , J  Phosphate, s i l i c a t e , and  a b l e q u a n t i t i e s o f s i l i c o n were p r e s e n t  v e r y low c o n c e n t r a t i o n s .  +  (meq/1)  e s t i m a t e d from conductivity (  1  9  6  1  aluminium i o n s were p r e s e n t  i n solu-  Although  consider-  i n s o l u t i o n , i t e x i s t s mainly i n  Some s u l p h a t e  i s present but i t occurs  Water samples were a n a l y z e d  )  .216 .210 .224 .249 .247 .301 .178 .165 .165 .203 .202 .210 .161 .143 .130  t i o n i n e x t r e m e l y low and r a r e l y d e t e c t a b l e c o n c e n t r a t i o n s .  i o n i c form, as d i s c u s s e d below.  I o n i c sum  .225 .212 .243 .275 .253 .309 .185 .149 .141 .186 .192 .196 .139 .120 .121  .179 .154 .178 .219 .204 .265 .113 .102 .102 .165 .142 .146 .099 .088 .076  6/7/72  stream A ti B II C H A it B H C H A •i B H C •i A II B II C H A it B II C  3  (meq/1)  non in  f o r c a l c i u m and magnesium  i n the p r e s e n t o f lanthanum o r s t r o n t i u m c h l o r i d e s t o a s c e r t a i n i f i n t e r f e r e n c e was  r e s p o n s i b l e f o r low  cation values still  and  contained  the method was acetylene  10-20%  cation values.  s i n c e even t h e p u r e s t lanthanum and  not used.  Calcium  flame as t h i s was  was  obtained  analyses,  always d e t e r m i n e d u s i n g a n i t r o u s o x i d e -  found t o c o n s i s t e n t l y g i v e r e a d i n g s which were about from the c o o l e r a i r - a c e t y l e n e flame.  d e t e c t i o n l i m i t f o r aluminium was  t h i s magnitude may  the  strontium;chlorides  s u f f i c i e n t c a l c i u m and magnesium t o i n t e r f e r e w i t h the  h i g h e r t h a n those o b t a i n e d  The  T h i s method f a i l e d t o i n c r e a s e  have been p r e s e n t  0.5  although  mg/1  so t h a t c o n c e n t r a t i o n s  they would have c o n t r i b u t e d  of little  127 to  the i o n i c  sum s i n c e aluminium i s l i k e l y t o o c c u r as v a r i o u s p o l y n u c l e a r  aluminium h y d r o x i d e In  complexes a t t h e pH o f t h e s o l u t i o n s  CHem, 1970).  g e n e r a l , t h e n , i t i s c o n s i d e r e d t h a t t h e c a t i o n a n a l y s e s were q u i t e  accurate. Of t h e a n i o n s , b i c a r b o n a t e accounted f o r about 30 - 50% o f t h e a n i o n i c sum and  s u l p h a t e , about 20 - 30%. As d i s c u s s e d below, b i c a r b o n a t e a n a l y s e s a r e  known t o o v e r e s t i m a t e t h e c o n c e n t r a t i o n o f b i c a r b o n a t e p r e s e n t by 20 - 40%. The  a n a l y t i c a l method .for s u l p h a t e had low r e s o l u t i o n and t h e c o n c e n t r a t i o n s  measured were close t o t h e d e t e c t i o n l i m i t .  Thus, i t i s f e l t  c o n c e n t r a t i o n s r e c o r d e d may a l s o be t o o h i g h . ide,  The o t h e r major a n i o n was c h l o r -  which accounted f o r 10 - 20% o f t h e a n i o n i c sum.  i n i t i a l l y performed  u s i n g two s e p a r a t e methods.  methods was q u i t e good  that the sulphate  C h l o r i d e a n a l y s e s were  Agreement between t h e two  (always w i t h i n 10%) so i t i s f e l t t h a t c h l o r i d e  analyses  are r e a s o n a b l y a c c u r a t e . The  e s t i m a t e d i o n i c sums were o b t a i n e d from t h e e m p i r i c a l e q u a t i o n :  E l e c t r i c a l c o n d u c t i v i t y = 100 x ( h a l f t h e sum o f a n i o n s and c a t i o n s ) which c a n y i e l d inaccurate results  (Logan,  1961).  Thus, d e s p i t e t h e f a c t t h a t t h e a n i o n i c  sums were c l o s e r t o t h e s e e s t i m a t e d sums than were the c a t i o n i c sums, t h e a n i o n i c sums a r e c o n s i d e r e d t o be i n c o r r e c t due t o o v e r e s t i m a t e d b i c a r b o n a t e and s u l phate c o n c e n t r a t i o n s . Effects of clearcutting C l e a r c u t t i n g has caused (Appendix E  slight,but generally s t a t i s t i c a l l y  X) i n c r e a s e s i n t h e e l e c t r i c a l c o n d u c t i v i t i e s o f streams A, B, D, and  (Table 4.9).  The i n c r e a s e s have been observed b o t h y e a r s f o l l o w i n g c l e a r -  c u t t i n g i n t h e case o f streams D and E . electrical  insignificant  F o r t h e o t h e r streams,  c o n d u c t i v i t y has been changed from C>A>B t o A>B>C.  the order o f  128 Average e l e c t r i c a l c o n d u c t i v i t i e s of streams before and a f t e r c l e a r cutting  Table 4.9  Stream B 18.8(2.9) Control(C) 19.3(3.6)  Stream A 19.1(1.8) 17.8(1.4) Control(C) 18.1(2.2) 15.8(2.6) before  after(1)  after  before  after .  before  before  a f t e r (2)  17.8(3.7) 17.7(4.5) after(1)  a f t e r (2)  Stream D 24.5(8.0) 22.7 (6.6) 25.0(6.8) Stream E 34.9(15.0) 31.8(11.6) 36.8(11.6) Control(C) 24.1(5.4) 20.5(5.7) 23.7(4.8) Control(C) 24.1(5.4) 20.5(5.7) 23.7(4.8) A l l values are i n micromho/cm at 25°C. parentheses.  Standard deviations are given i n  Values are f o r the periods: A  -  November 1, 1972 to A p r i l 1, 1973 before c l e a r c u t t i n g November 1, 1973 to A p r i l 1, 1974 a f t e r c l e a r c u t t i n g  B  -  October 1, 1972 to A p r i l 1, 1973 before c l e a r c u t t i n g October 1, 1973 to A p r i l 1, 1974 a f t e r c l e a r c u t t i n g  D,E -  A p r i l 1, 1971 to November 1, 1971 before c l e a r c u t t i n g A p r i l 1, 1972 to November 1, 1972 a f t e r c l e a r c u t t i n g - year 1 A p r i l 1, 1973 to November 1, 1973 a f t e r c l e a r c u t t i n g - year 2  Increases i n e l e c t r i c a l conductivity are expected i f c l e a r c u t t i n g increases the concentration of dissolved ions i n stream water, as has been found i n studies from Hubbard Brook, both following forest cutting and herbicide a p p l i c a t i o n (Likens et al., 1970) and commercial c l e a r c u t t i n g (Pierce et al., 1972). Increases i n the concentration of t o t a l dissolved s o l i d s  (and hence i n e l e c t r i c a l  conductivity) have also been observed following c l e a r c u t t i n g i n Oregon (Fredriksen, 1971). 7.  Ions and dissolved s i l i c a  1)  Potassium  Seasonal  behaviour  In the undisturbed watersheds, potassium concentrations i n stream water average about .1 mg/litre and, unlike a l l the other major ions, showed no pronounced seasonal trends, although concentrations were s l i g h t l y higher during l a t e summer and e a r l y autumn (Figure 4.31). elsewhere(Table  4.10).  This i s s i m i l a r to r e s u l t s obtained  129  C1/9W) NQIlbcJlN33NQ3  130 Figure 4.32  Relationships between streamwater potassium concentrations and discharge.  POTASSIUM CONCENTRATION VERSUS DISCHARGE. STREAM A . BEfiHE CUrBCurn.tG • flf TEH CLEPRCUITIHG  Y = .1465 + .0645 (-) .. (r = .49)  -1—  E.5  1  -1  13.0  13.5  25.0  T 32.5  45.5  39.0  £2.0  65.0  DISCHARGE (UTRES/SEC1 POTASSIUM CONCENTRATION VERSUS DISCHARGE. STREAM B  . BEFORE O E S R C U n i W • WTES OERSQiniHS  Y = .0859 + .0438(-) (r = .33) •  •  0.0  2S.0  •  * .  •  52.0  73.0  104.0  n^o  33^  2Ta  130.0  1SS.0  —i  DISCHARGE (UTRES/SECJ POTASSIUM CONCENTRATION VERSUS DI5CHARGE. STREAK C  182.0  209.0  rTo  eTo  —I  250.0  y  °' • 0  "~  a  svo  uTa  DISCHARGE IUTKE5/SEC)  vTa 0  Regressions are f o r "before c l e a r c u t t i n g " data only. n i f i c a n t r e l a t i o n s h i p was found f o r stream C.  na a  "  0A  No s i g -  131  F i g u r e 4.33  Concentration 1.1-1 1.0 A  Streamwater c a t i o n c o n c e n t r a t i o n s d u r i n g a storm event (27-29 November, 1973)  (mg/1)  STREAM A  Discharge (litres/sec) 150 50 10  Concentration 1.2  (mg/1)  STREAM B  Discharge (litres/sec) 1000  I- 500  Concentration  (mg/1)  STREAM C  (undisturbed)  1.21.0. 0.8Discharge (litres/sec) 500  0 ^  A l l N H 4 c o n c e n t r a t i o n s £.01 mg/1  132 V a r i a t i o n with discharge Potassium concentrations generally tended to decrease with increasing discharge  (Figure 4.32) although, f o r an i n d i v i d u a l storm event, the concen-  t r a t i o n s c l e a r l y increased with increasing discharge (Figure 4.33).  This  apparent discrepancy might be due to potassium concentrations being lower at higher discharges f o r steady flows, although e x h i b i t i n g increases with i n creasing discharge during storm events.  This i s supported by the observation  that potassium concentrations i n streamwater during wet winters generally tend to be lower than those during dry summers. Table 4.10  Seasonal v a r i a t i o n of cation concentrations i n streamwater i n temperate regions  Location  K  Na  Mg  Reference  Ca  relatively constant but slight i n crease i n l a t e summerearly autumn  early autumn maximum, winter minimum  early autumn maximum, winter minimum  early autumn maximum, winter minimum  Seymour watershed, Vancouver  relatively constant  higher i n summer, lower i n winter  higher i n summer, lower i n winter  higher i n summer, lower i n winter  H.J. Andrews Experimental Forest, coastal Oregon  relatively constant  late summer maximum, winterspring minimum  l a t e summer maximum, winterspring minimum  l a t e summer maximum, winterspring minimum  Coastal California  relatively constant but lower i n winter  higher i n autumn, lower i n winter  higher i n autumn, lower i n winter  higher i n autumn, lower i n winter  early autumn maximum, spring snowmelt minimum  early summer maximum, spring snowmelt minimum  early summer maximum, spring snowmelt minimum  Haney  Sagahen Ck. Eastern California  Ohio  —•  relatively constant  -  -  -  This study  Zeman, 1973  Rothacher et al., 1967; Fredricksen, 1972  Steele, 1968  Johnson and Needham, 1966  Taylor et al. 1971  133  T a b l e 4.10 c o n t . Location  K  Mg  Na  Ca  Reference  relatively constant but maximum i n autumn  autumn maximum, l a t e winter m i n i mum  autumn maximum, e a r l y summer m i n i mum  autumn maximum, e a r l y spring minimum  C l e a v e s et al., 1970  relatively constant but s l i g h t decrease i n summer and increase i n autumn  autumn maximum, s p r i n g minimum  relatively c o n s t a n t but slight rise i n autumn  slight i n crease i n autumn, and decrease i n spring  Johnson et al., 1969; L i k e n s et al., 1967 and 1970  autumn maximum, w i n t e r minimum  autumn maximum, w i n t e r minimum  e a r l y autumn maximum,wint e r minimum  autumn maximum, w i n t e r minimum  Johnson and Swank, 1973  2. Grass S shrub watershed  l a t e winter maximum,late summer m i n i mum  variable  l a t e winter maximum,late summer m i n i mum  variable  Agricultural watersheds, Norfolk, Britain  autumn maximum, s p r i n g minimum  l a t e summer- r e l a t i v e l y autumn maxi- c o n s t a n t mum, l a t e winter-spring minimum  Finland  autumn maximum, w i n t e r minimum  Maryland  Hubbard Brook, New Hampshire  Coweeta, North Carolina 1. F o r e s t e d watershed  -  autumn maximum, w i n t e r minimum  w i n t e r maximum , summer minimum  autumn maximum, w i n t e r minimum  Edwards, 1973a  V i r o , 1953  V a r i a t i o n between streams In the undisturbed condition, potassium concentrations were usually highest i n stream A which may be due to one or more of the following f a c t o r s : 1.  There  may be s l i g h t chemical and mineralogical differences between the s o i l s and bedrock of the d i f f e r e n t watersheds; 2.  Although the watersheds have the same  o v e r a l l aspect, a substantial portion of watershed A consists of southwesterly facing slopes where decomposition and m i n e r a l i z a t i o n may be more rapid than on cooler exposures, which are more common i n watershed B. will be higher i n the lower elevation watershed A; 3.  Also s o i l  temperatures  Differences i n maturity  of the forest ecosystems may cause differences i n the amounts of chemical nutrients l o s t to streams.  '  Higher calcium and magnesium concentrations i n stream C suggest that factors 2 and, p a r t i c u l a r l y , 3, are of lesser  importance.  T a b l e 4.11  V a r i a t i o n o f c a t i o n c o n c e n t r a t i o n s i n streams i n temperate r e g i o n s .with i n c r e a s i n g stream d i s c h a r g e  Location  Haney  Seymour watershed, Vancouver  K  Na  some i n c r e a s e s some decreases decreases  no significant relationship  no significant relationship  Mg  Sagahen Ck., Eastern California •  Western Montana  Reference  decreases  decreases  T h i s study  no significant relationship  no significant relationship  L . J . Zeman, Faculty of Forestry, University of B r i t i s h Columbia: Personal communication  decreases  Fredriksen, 1972  H.J. Andrews Experimental Forest, coastal Oregon  Coastal California  Ca  decreases  decreases  decreases  S t e e l e , 1968  decreases  decreases  decreases  Johnson and Needham, 1966  K-Na combined i n c r e a s e  decreases  decreases  W e i s e l and N e w e l l , 1970  decreases  decreases  Johnston and Doty, 1972  decreases  -  Northern Utah  does n o t decrease  Ohio  no significant relationship  Maryland  increases  decreases slightly  increases  increases  C l e a v e s et al._ 1970  Hubbard Brook, New Hampshire  increases slightly  decreases  decreases slightly  no significant relationship  Johnson e t al.3 1969  Coweeta, * North Carolina  increases  no significant relationship  increases  no significant relationship  Johnson and Swank, 1973  Switzerland  no significant relationship  decreases  no significant relationship  decreases  Keller, 1970a, b  Bog and p e a t moorland, Britain  initially decreases, then increases  no significant relationship  decreases  C r i s p , 1966  Agricultural watersheds, Norfolk, Britain  increases  decreases  decreases  no significant relationship  Edwards, 1973a, b  Japan  increases  no significant relationship  decreases  Iwatsubo and Tsutsumi, 1968  decreases  -  -  -  T a y l o r et at,, 1971  Johnson and Swank c o n s i d e r e d the c o n c e n t r a t i o n s o f a l l four c a t i o n s t o be i n d e pendent o f d i s c h a r g e . However, data p r e s e n t e d i n t h e i r paper i n d i c a t e t h a t t h i s i a n o t the case f o r potar.sium ami magnesium c o n c e n t r a t i o n s , both o f which appear to i n c r e a s e with i n c r e a s i n g discharge.  135 Effects of clearcutting C l e a r c u t t i n g has had a more d r a m a t i c t h a n on t h o s e o f any o t h e r i o n .  e f f e c t on p o t a s s i u m  concentrations  F o l l o w i n g c l e a r c u t t i n g , potassium  concentra-  t i o n s i n streams A and B r o s e s h a r p l y d u r i n g autumn and have remained a b n o r m a l l y high throughout the winter  ( F i g u r e 4.31, T a b l e 4.12).  Potassium c o n c e n t r a t i o n s  i n streams D and E have been a b n o r m a l l y h i g h f o r two y e a r s cutting  ( F i g u r e 4.34, T a b l e 4.12).  been h i g h l y s i g n i f i c a n t T a b l e 4.12  following clear-  I n a l l f o u r streams t h e i n c r e a s e s have  statistically  (Appendix X ) .  Average c o n c e n t r a t i o n s o f c a t i o n s i n streamwater b e f o r e and a f t e r clearcutting.  K 1. Stream A before after control(C) before after 2. Stream B before after control(C) before after  Na  Mg  NH,  Ca  .27(.03) .23 ( . 0 2 )  1.3(.2) 1.2(.2)  .OK.01)  .80(.25) .79(.14)  .25(.04) .2K.04)  1.3(.3) 1.3(.3)  •02(.03) 0  .09(.02) .27(.19)  ,88(.30) .93(.21)  .28(.06) .27 (.09)  1.4(.3) 1.3(.3)  ,01(.02) 0  .09(.04)  ,89(.30) .87 (.21)  .27(.06) .25(.09)  1.5(.5) 1.5(.6)  ,02(.03) 0  • 15(.02) .29(.05)  1.02(.21) 1.03(.ll)  .09(.04) .08(.02)  .08(.02)  0  3. Stream D before after(1) after(2)  .10(.06) .30(.16) .20(.08)  1.02(.36) 1.03(.30) 1.14(.29)  .42(.19) .37(.13) .52(.20)  1.5(.6) 1.6(.6) 2.2(.9)  ,03(.05) 0  Stream E before after(1) after(2)  .1M.06) .27(.08) .26(.10)  1.36(.45) 1.44(.43) 1.67(.37)  .63(.30) .59(.24) .86(.39)  2.K.9) 2.7(1.3) 3.6(1.6)  .03(.03) 0  1.18(.26) 1.09(.33) 1.23(.28)  .36(.09)  1.6(.4) 1.7(.7) 2.2(.7)  ,02(.03) 0  control(C) before after(1) after(2) All  .06(.05) .09(.03)  .08(.04)  .3K.09)  .42(.14)  concentrations are i n m g / l i t r e  Standard d e v i a t i o n s given i n parentheses cont.  136 Stream A  November 1, 1972 to A p r i l 1, 1973 before c l e a r c u t t i n g November 1, 1973 to A p r i l 1, 1974 a f t e r c l e a r c u t t i n g  Stream B  October 1, 1972 to A p r i l 1, 1973 before c l e a r c u t t i n g October 1, 1973 to A p r i l 1, 1974 a f t e r c l e a r c u t t i n g  Streams D & E  A p r i l 1, 1971 to November 1, 1971 before c l e a r c u t t i n g A p r i l 1, 1972 to November 1, 1972 a f t e r c l e a r c u t t i n g (year 1) A p r i l 1, 1973 to November 1, 1973 a f t e r c l e a r c u t t i n g (year 2)  Potassium i s not a s t r u c t u r a l component of plant tissue  ( G i l b e r t , 1957)  so that i t can be e a s i l y leached from l i v i n g or decomposing plant m a t e r i a l . This i s i l l u s t r a t e d by studies of nutrient enrichment of r a i n passing through forest canopies.  These show that, of a l l the major cations, potassium concen-  t r a t i o n s undergo the greatest increases (Abee and Lavender, 1972; Eaton et al.  3  1973; Gorham, 1961).  In a d d i t i o n , Slack (1964) found that accumulation of l e a f  l i t t e r i n pools caused greater increases i n potassium concentrations than i n those of any of the other major cations.  At Hubbard Brook decomposing forest  l i t t e r released potassium ions at a greater rate than that f o r any of the other major cations  (Gosz et al.  3  1973).  Furthermore, the forest cutting and h e r b i -  cide a p p l i c a t i o n treatment at Hubbard Brook increased potassium concentrations i n streamwater to a greater extent than for the other major cations al. j 1970).  (Likens et  Greatly increased potassium concentrations i n streams have been  noted a f t e r c l e a r c u t t i n g i n the H.J. Andrews Experimental Forest i n Oregon, although calcium concentrations were increased to a greater extent (Fredriksen, 1971), and also a f t e r c l e a r c u t t i n g and slashburhing i n the Alsea basin i n Oregon (Brown et al.  3  1973).  Thus, i n the l i g h t of the above studies, the- increase i n potassium concentrations i n the streams following c l e a r c u t t i n g i s expected.  It  i s most l i k e l y  due to leaching by water of potassium from vegetation within the watershed. The large amount of slash i n and above the streams  (Figure 4.11)  i s l i k e l y to  provide the source for much of t h i s potassium although increased potassium concentrations i n s o i l waters have also been noted.  F i g u r e 4.34  S t r e a m w a t e r p o t a s s i u m c o n c e n t r a t i o n s - s t r e a m s D and E  ONDJFMRMJJflSQNDJFMflMJJflSONDJFMflMJJflSQNDJFMfl  1970  1971  1972  1973  1974 OJ ~0  138 2)  Sodium  Seasonal b e h a v i o u r Sodium c o n c e n t r a t i o n s showed pronounced  s e a s o n a l v a r i a t i o n s w i t h maxima  d u r i n g e a r l y autumn and minima d u r i n g w i n t e r t h a t found i n o t h e r s t u d i e s  ( F i g u r e 4.35).  T h i s agrees w i t h  (Table 4.10).  V a r i a t i o n with discharge D e s p i t e l a r g e v a r i a t i o n s , sodium i n c r e a s i n g d i s c h a r g e ( F i g u r e s 4.33 found i n o t h e r s t u d i e s V a r i a t i o n between  c o n c e n t r a t i o n s tended t o d e c r e a s e w i t h  and 4.36).  T h i s a l s o agrees w e l l w i t h t h a t  (Table 4.11).  streams  Both b e f o r e and a f t e r c l e a r c u t t i n g , sodium c o n c e n t r a t i o n s tended t o be h i g h e s t i n stream A and s i m i l a r i n streams B and C. to  T h i s i s l i k e l y t o be  due  the same r e a s o n s d i s c u s s e d above f o r p o t a s s i u m . Sodium c o n c e n t r a t i o n s i n the streams have always been h i g h e r t h a n t h o s e  of  the o t h e r major a l k a l i - m e t a l , p o t a s s i u m .  1970) 1.  and i s due t o one o r more o f the f o l l o w i n g  2.  i n the watersheds  the 5.  1970).  a t Haney.  1970). Once l i b e r a t e d , p o t a s s i u m has a s t r o n g tendency t o be r e i n c o r p o r a t e d  w e a t h e r i n g p r o d u c t s , e s p e c i a l l y c e r t a i n c l a y m i n e r a l s (Hem,  4.  (Hem,  Sodium i s more r e a d i l y l i b e r a t e d from s i l i c a t e m i n e r a l s than i s p o t a s s i u m  (Hem,  al.,  (Hem,  factors:  Sodium i s u s u a l l y more abundant t h a n p o t a s s i u m i n igneous r o c k s  Such r o c k s form the bedrock  3.  T h i s i s u s u a l l y the case  1970;  Johnson  into et  1968). B i o t a may  u t i l i z e a h i g h e r p r o p o r t i o n o f the a v a i l a b l e p o t a s s i u m than o f  a v a i l a b l e sodium  (Johnson  et al.,  1968;  Likens  et al.,1967).  Once i n s o l u t i o n , p o t a s s i u m tends t o be adsorbed on s u r f a c e s o f p a r t i c l e s  more r e a d i l y than i s sodium  (Bear, 1964).  E f f e c t s of c l e a r c u t t i n g There has been l i t t l e  e f f e c t o f c l e a r c u t t i n g on sodium c o n c e n t r a t i o n s  F i g u r e 4.35  2  Streamwater  sodium c o n c e n t r a t i o n s - streams A, B, and C  SODIUM T  6-  fl  STREAM fl  B  STREAM B  C  STREAM C  2-1  8-  4clearcuttmgB  n  Im  iiiiiiniini mini m m i  iiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiminiiiii iium "tin imiii mini  iiiiuin  ONDJFMflMJJflSONDJFMflMJJRSON'DJFMflMJJflSONDJFMfl  1970  1971  1972  1973  1974  140 Figure 4.36  P "1  Relationships between sreamwater sodium concentrations and discharge.  SODIUM CONCENTRATION VERSUS DISCHARGE. STREAM A . 8CFCRE CUrHCt;:!:*}  Regressions are f o r "before c l e a r c u t t i n g " data only.  141 ( F i g u r e 4.35, found  T a b l e 4.12), and  no  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 were  (Appendix X ) . Although  the f o r e s t c u t t i n g and h e r b i c i d e a p p l i c a t i o n experiment a t  Hubbard Brook r e s u l t e d i n i n c r e a s e d sodium c o n c e n t r a t i o n s i n streamwater, p e r c e n t a g e i n c r e a s e f o r sodium was et al. j H.J.  1970).  the lowest o f a l l the major c a t i o n s  S i m i l a r l y , t h e c l e a r c u t t i n g and  Andrews E x p e r i m e n t a l  the  (Likens  s l a s h b u r n i n g experiment i n the  F o r e s t i n Oregon a l s o produced i n c r e a s e s i n sodium  c o n c e n t r a t i o n s w h i c h were p r o p o r t i o n a t e l y l e s s than the i n c r e a s e s i n the t r a t i o n s o f the o t h e r major c a t i o n s  concen-  ( F r e d r i k s e n , 1971).  Thus, sodium i n t h e streams a t Haney has behaved i n a s i m i l a r f a s h i o n t o t h a t found 3)  i n these o t h e r s t u d i e s .  Magnesium and  Seasonal  calcium  behaviour  Both i o n s e x h i b i t e d i d e n t i c a l s e a s o n a l b e h a v i o u r  w i t h maximum  t i o n s i n e a r l y autumn and minimum c o n c e n t r a t i o n s i n w i n t e r  concentra-  ( F i g u r e 4.37).  T h i s agrees w e l l w i t h the r e s u l t s o f o t h e r s t u d i e s (Table 4.10). The  a p p a r e n t anomalous s e a s o n a l b e h a v i o u r  (1973a) f o r watersheds i n B r i t a i n may  be due  o f c a l c i u m r e p o r t e d by Edwards  to inaccurate calcium analyses  t o the s o l u b i l i t y r e l a t i o n s h i p s o f the two main c a l c i u m s o u r c e s bonate and  calcium sulphate.  t i o n s decrease e f f e c t s on  - calcium car-  With i n c r e a s i n g discharge, bicarbonate  whereas s u l p h a t e c o n c e n t r a t i o n s i n c r e a s e , h a v i n g  the s o l u b i l i t i e s o f the c a l c i u m  concentra-  opposite  salts.  Where the source o f c a l c i u m i s almost e n t i r e l y c a l c i u m c a r b o n a t e , limestone decrease  country  i n Kentucky, i t has been found  as d i s c h a r g e i n c r e a s e s and  on temperature o r season  that calcium  ( T h r a i l k i l l , 1972).  o f c a l c i u m i s v e r y d i f f e r e n t t o t h a t a t Haney. chemical  as i n  concentrations  a p p a r e n t l y depend more on d i s c h a r g e  than  However, t h e s i t u a t i o n i n t h a t  study, where streams were i n a warmer c l i m a t e and  and  or  i n c o n t a c t w i t h an abundance  In the former c a s e , p h y s i c a l  p r o p e r t i e s o f the streams a r e q u i t e l i k e l y t o c o n t r o l c a l c i u m  142  F i g u r e 4.37  c o n c e n t r a t i o n s - streams A, B, and C  MAGNESIUM  1 CD  streamwater magnesium and c a l c i u m  clearcuttmgA  fl = STREAM fl  T  8  CL CH  UJ <_J O CJ  HIIHIIIIIIl  ""'".II  iniMiiiimimiiMimii  fl  Illlllllllllllllllllllllllllllllll n•• - . , Q  C  n  " , r u p  ONDJFMflMJJflSONDJFMflhJJRSONDJFMflMJJRSONDJFMfl CALCIUM  4T  fl = STREAM A B = STREAM B  |  3.2 t  §  2.4  £  1.6  C = STREAM C  C  UJ CJ O CJ  clearcuttinj A  o • °  0  t  clearcutting-  |  t  1  mill  1970  I  "'"  197  1  1  1  1972  1  1  ,  illinium r  1973  1  -  M  n  1974  143 c o n c e n t r a t i o n s i n streamwater, whereas, a t Haney, c a l c i u m c o n c e n t r a t i o n s i n streamwater would be more dependant on s e a s o n a l l y induced decomposition V a r i a t i o n with The charge  and m i n e r a l  weathering.  discharge  c o n c e n t r a t i o n s o f both  ( F i g u r e s 4.33,  other s t u d i e s  changes i n b i o l o g i c a l  4.38  and  i o n s tended t o d e c r e a s e  with increasing d i s -  4.39), g e n e r a l l y a g r e e i n g w i t h the r e s u l t s  of  (Table 4.11).  V a r i a t i o n between streams I n the u n d i s t u r b e d  streams c a l c i u m was  b e i n g the t h i r d most important  a f t e r sodium  t h e dominant c a t i o n w i t h magnesium (Appendix V ) .  o r d e r o f c a t i o n s i n streams i n humid temperate r e g i o n s  T h i s i s the  (Hem,  1970;  usual  Livingstone,  1963). When c o n c e n t r a t i o n s were h i g h  ( l a t e summer - e a r l y autumn) b o t h  calcium  and magnesium c o n c e n t r a t i o n s were h i g h e s t i n stream C but when c o n c e n t r a t i o n s were low  ( w i n t e r ) , t h e y were l o w e s t  bedrock and  soil  chemistry  i n stream C  ( F i g u r e 4.38) .  o r i n w e a t h e r i n g r a t e s may  t r a t i o n s i n stream C d u r i n g summer and  Differences i n  account f o r higher  e a r l y autumn, whereas g r e a t e r  biological  a c t i v i t y i n the warmer, lower e l e v a t i o n watersheds A and B d u r i n g t h e may  a c c o u n t f o r the w i n t e r b e h a v i o u r .  had  l a r g e r and more p r o l o n g e d  E f f e c t s of  noticeably colder  snowpacks than t h e o t h e r two  and  watersheds.  no pronounced e f f e c t on c a l c i u m o r magnesium concen-  t r a t i o n s i n streams A and B s l i g h t , but s t a t i s t i c a l l y statistically  and E  winter  clearcutting  C l e a r c u t t i n g has had  and  Watershed C was  concen-  ( F i g u r e 4.37,  T a b l e 4.12).  I t has, however, caused  i n s i g n i f i c a n t , i n c r e a s e s i n magnesium  concentrations  s i g n i f i c a n t i n c r e a s e s i n c a l c i u m c o n c e n t r a t i o n s i n streams D  (Appendix X ) . R e s u l t s from streams D and E  ( F i g u r e 4.40)  growing s e a s o n f o l l o w i n g c l e a r c u t t i n g was c o n c e n t r a t i o n s became apparent.  i n d i c a t e t h a t a l m o s t an  necessary  entire  b e f o r e changes i n c a l c i u m  S i m i l a r r e s u l t s have been noted  near Hubbard  144 Figure 4.38  Relationships between streamwater magnesium concentrations and discharge.  MAGNESIUM CGNCEN1RATICN VERSUS DISCHARGE  SISEAM A  . BEfCUE. CLFWCUHING 0 BFIH CLFRRLUIIINC  .4243 - 0.14301ogX (r = .72)  — i — 6.5  13.0  19.5  2B.0  32.5  39.0  DISCHARGE ILITRE5/5EC) STREAM B MAGNESIUM CONCENTRATION VERSUS DISCHARGE  ~l  6S.0  45.5  . BEFORE Q.ERRCUT7 ING 0 UTTER O E R R O i r T l H S  Y = 0.4007 - .094161ogX (r = .76)  52.0  7B.0  104.0  130.0  156.0  260.0  „ DISCHARGE (LITRES/SEC) MAGNESIUM CONCENTRATION VERSUS DISCHARGE. STREAM C  Y - .4508 - .12971ogX (r = .66)  o.o  11.0  33.0  4-1.0  50 0  DISCHARGE III IRES/SEC)  66.0  -1  77.0  Bfl.O  Regressions are f o r "before c l e a r c u t t i n g " data only.  . 110.0  145 Figure 4.39 Relationships between streamwater calcium concentrations and discharge. CALCIUM  CONCENTRATION  VERSUS  DISCHARGE.  'STREMM  9  . 9EFOK riEWCUTTING I flFIEH CLt.iiJUIII.%  T 0.0  1 S.S  CALCIUM  1 13.0  1 19.5  1 2 6 . 3  1 3 2 . 5  1 3 9 . 0  DISCHARGE (LITRES/SEC) CONCENTRATION VERSUS DISCHARGE. STREAM B  1 45.5  1 52.0  1 58.3  . BEFORE CLEARCUTTING I AFTER CLEARCUTTING  Y = 2.104 - 0.55671ogX (r = .77)  Regressions are f o r "before c l e a r c u t t i n g " data only.  1 65.0  F i g u r e 4.40  Streamwater calcium concentrations - streams D and E  CALCIUM  8T  C  STRERM  C  D  STREAM  D  E  STRERM  E  6-  Felling  Yarding  420  III miii  iiiiiii IIIIII iiii III iimi IIIIIII mill IIIIIIIIM  ONDJFMRMJJflSONDJFMRMJJflSONDJFMflMJJFlSONDJFMR  1970  1971  1972  1973  1974  147 Brook  ( P i e r c e et al.,  immediately  1972)  where potassium  c o n c e n t r a t i o n s i n c r e a s e d almost  a f t e r an October c l e a r c u t t i n g whereas no n o t i c e a b l e i n c r e a s e s i n  magnesium o r c a l c i u m c o n c e n t r a t i o n s o c c u r r e d u n t i l the f o l l o w i n g summer. was  It  c o n s i d e r e d t h a t the season o f c u t t i n g c o u l d i n f l u e n c e the amount o f chemi-  c a l s l o s t from l a n d t o streams, w i t h g r e a t e r l o s s e s from summer c l e a r c u t t i n g s than  from autumn c l e a r c u t t i n g s due  then one  would expect  to p r o l o n g e d  s i t e exposure.  I f t h i s i s so  a g r e a t e r i n c r e a s e i n l o s s e s from watershed B than  watershed A s i n c e B was  c l e a r c u t i n summer whereas A was  from  c l e a r c u t i n autumn.  In t h i s r e s p e c t i t i s noteworthy t h a t magnesium c o n c e n t r a t i o n s i n stream B tended t o be h i g h e r  i n i t i a l l y f o l l o w i n g c l e a r c u t t i n g than those i n A u n l i k e  the values before c l e a r c u t t i n g .  No  d i s t i n c t t r e n d s can be  seen i n c a l c i u m  values. 4)  I r o n , manganese, and  aluminium  D u r i n g more than t h r e e y e a r s o f sampling  streams A, B, and C,  measurable  c o n c e n t r a t i o n s o f i r o n have been found o n l y f o u r times whereas measurable conc e n t r a t i o n s o f manganese and  aluminium have not y e t been found.  d e t e c t i o n l i m i t s a r e g i v e n i n T a b l e 3.1.  These elements a r e u s u a l l y p r e s e n t  i n v e r y low c o n c e n t r a t i o n s i n streams i n humid temperate r e g i o n s 1970;  Analytical  (e.g.  Hem,  L i v i n g s t o n e , 1963).  I r o n and manganese I n streamwater c l o s e t o n e u t r a l pH, as p a r t i c u l a t e F e ( 0 H )  3  any  i r o n p r e s e n t would e x i s t  o r as an o r g a n i c complex which may  Manganese behaves i n a s i m i l a r f a s h i o n  (Hem,  1970).  a l s o be  particulate.  Thus, c o n c e n t r a t i o n s  the uncomplexed s o l u b l e i o n s o f t h e s e m e t a l s i n u n p o l l u t e d streams a r e t o be q u i t e low,  as has been found  by Hem  (1972), Rothacher et al., (1967), W e i s e l  (1970), L i v i n g s t o n e  and Newell  mainly  of  likely  (1963), Perhac  (1970), and many o t h e r s .  S i g n i f i c a n t c o n c e n t r a t i o n s o f i r o n and manganese have been r e p o r t e d i n streams f o l l o w i n g l e a f f a l l d u r i n g low F e l t z , 1968).  The  f l o w p e r i o d s i n autumn ( S l a c k , 1964;  Slack  and  more i n t e n s e the c o l o u r o f the water, the h i g h e r were the  148 i r o n and manganese concentrations.  This colouration might have been due to  the presence of various carboxylic acids which e x i s t i n water as a c o l l o i d a l s o l to which cations may be either complexed or adsorbed (Lamar and G o e r l i t z , 1966).  The presence of such compounds may allow s i g n i f i c a n t concentrations of  i r o n and manganese ions to occur i n a dissolved form i n s o l u t i o n .  In t h i s r e -  spect, i t i s noteworthy that measurable i r o n and manganese concentrations were found i n streams D and E only during low flow periods i n autumn when the streams were s l i g h t l y coloured (Figure 4.41).  Decreases i n i r o n and manganese concen-  trations with increasing discharge, as has been observed elsewhere (Buscemi, 1969), may be p a r t l y responsible f o r the absence of detectable i r o n and manganese concentrations during the r e s t of the year. Aluminium The detection l i m i t f o r aluminium by the a n a l y t i c a l method used i n t h i s study i s 0.5 mg/1.  Because of pH dependent s o l u b i l i t y r e l a t i o n s h i p s , t h i s i s  greater than the concentrations of aluminium usually found i n water of nearneutral pH.  Only at very low pH values do aluminium concentrations appear to  increase s i g n i f i c a n t l y  (Hem, 1970) .  At Hubbard Brook, aluminium concentrations  i n undisturbed streams were less than 0.5 mg/1 nearly a l l the time (Likens et al.  3  1970).  Aluminium concentrations also increased with increasing discharge  (Johnson et al., 1969). E f f e c t s of c l e a r c u t t i n g Iron and manganese Neither of these ions has yet been detected i n streams A or B following clearcutting.  This i s expected  i n view of t h e i r low concentrations i n natural  waters and t h e i r tendency to increase i n concentration only during the low flow periods of l a t e summer and early autumn.  Detectable concentrations have been  found i n streams D and E during t h i s time of the year.  Although manganese  concentrations were not determined p r i o r to c l e a r c u t t i n g , i r o n concentrations were and they show 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 increase following c l e a r c u t t i n g  CONCENTRATION (MG/L)  CONCENTRATION (MG/L) O O  — 1 —  CD  o  DO —  H  _  ro  — 1 —  o  01  — 1 —  —1  m  CD  11  O  I  o cn  — 1 —  cn  — 1 —  ro  — 1 —  ID 11  70  11  11  in  —1  —1  70  70  m n  m m x> XI m  CO  m  a  LT> U)  —1  cn —H—  m  o  0 11  3  to —i 70 m  t—•  -D  cn r* M A  a  C rr  CD  3 0> 3. 3 P 1—1  w  a  8 Cl  CD  1 O  (V)  1  n  O  0  —  0 3 0 CD 3  i m  H  I C Q  0  "  u  ft  m  l to rr  jams  »1  CD  0  (»  CO  O. w  m  CD 4^  ZD 1X1  150  (Figure 4.41; Appendix X ) .  Fredriksen (1971) found increases i n both i r o n and  manganese concentrations following c l e a r c u t t i n g and slashburning i n Oregon but the i r o n increases were only very s l i g h t . Aluminium Detectable aluminium concentrations have yet to be found i n any of the streams at Haney.  Even i n streams which are many times more concentrated  than  those at Haney, such as streams i n the Chilliwack v a l l e y area of B.C. whose e l e c t r i c a l c o n d u c t i v i t i e s were up to 440 micromhos/cm at 25°C, f a i l e d to exh i b i t measurable concentrations of aluminium.  However, following the f o r e s t  cutting and herbicide a p p l i c a t i o n treatment at Hubbard Brook, aluminium concentrations increased from around 0.2 mg/1 to between 1 and 3 mg/1, these concentrations being greatest during autumn. Thus, i t appears that i f increased concentrations of i r o n and manganese are to occur following c l e a r c u t t i n g , they w i l l not be observed u n t i l l a t e summer or early autumn and are not l i k e l y to be very high.  Aluminium concentra-  tions are l i k e l y to remain below detectable l e v e l s following c l e a r c u t t i n g . 5)  Ammonium and n i t r a t e The a n a l y t i c a l method f o r n i t r a t e a c t u a l l y measured n i t r i t e as well as  n i t r a t e , but since n i t r i t e i s u s u a l l y present i n only very small amounts (Feth, 1961; Hem, 1970; Livingstone, 1963) the a n a l y t i c a l r e s u l t s can be assumed to c l o s e l y approximate n i t r a t e concentrations. Seasonal  behaviour  Weekly f l u c t u a t i o n s i n the concentrations of ammonium and n i t r a t e ions appear to be greater than seasonal f l u c t u a t i o n s so that c l e a r seasonal trends are not apparent.  Ammonium concentrations tended to be lower during the grow-  ing season and higher during the r e s t of the year s i m i l a r behaviour  (Figure 4.42) and t h i s i s  to that found by Zeman (1973) f o r Seymour watershed.  Nitrate  trends were more apparent with concentrations tending to be higher i n winter and lower i n summer (Figure 4.43).  CONCENTRATION  (MG/L)  CONCENTRATION (MG/L)  The  152 low ammonium and r e l a t i v e l y h i g h n i t r a t e c o n c e n t r a t i o n s may be a r e -  s u l t o f h i g h d i s s o l v e d oxygen c o n c e n t r a t i o n s i n t h e streams which o x i d a t i o n o f ammonium t o n i t r a t e .  The d e c r e a s e  i n nitrate  facilitate  concentrations  d u r i n g t h e summer when d i s s o l v e d oxygen c o n c e n t r a t i o n s a l s o d e c r e a s e d ,  and t h e  absence o f a c o r r e s p o n d i n g  t h a t the  decrease  i n c r e a s e i n ammonium c o n c e n t r a t i o n s suggest  i n n i t r a t e was caused by i n c r e a s e d b i o l o g i c a l uptake o f n i t r o g e n com-  pounds which o c c u r s d u r i n g t h e growing season, as has been p o s t u l a t e d f o r Hubbard Brook  (Johnson et al., 1969; L i k e n s et al., 1970) and elsewhere  1966) . I n c r e a s e s  i n n i t r a t e c o n c e n t r a t i o n s i n C a l i f o r n i a n streams d u r i n g e a r l y  w i n t e r have been a t t r i b u t e d t o l e a c h i n g by r a i n o f n i t r o g e n o u s products  (Feth,  from d e c a y i n g  vegetation  ( F e t h , 1961).  decomposition  Such p r o d u c t s would accumulate  d u r i n g t h e d r y p e r i o d s o f l a t e summer a t Haney and i t i s l i k e l y t h a t w i n t e r r a i n s would f l u s h them away.  N i t r a t e concentrations decreased  throughout  s p r i n g as b i o l o g i c a l a c t i v i t y i n c r e a s e d , u n l i k e t h e s i t u a t i o n a t Hubbard Brook where n i t r a t e c o n c e n t r a t i o n s r e a c h e d  a maximum d u r i n g s p r i n g .  n i t r a t e i s s t o r e d i n t h e w i n t e r snowpack and c o n c e n t r a t e d throughout the winter streams  T h e r e , however,  by e v a p o r a t i o n  s o t h e s p r i n g snowmelt r u n o f f can s u p p l y much n i t r a t e t o  ( L i k e n s et al., 1970).  Buscemi  (1969) found  a similar increase i n n i -  t r a t e c o n c e n t r a t i o n s i n streams i n Idaho d u r i n g the s p r i n g snowmelt p e r i o d , and h i g h e r n i t r a t e c o n c e n t r a t i o n s d u r i n g t h e s p r i n g snowmelt p e r i o d have been measu r e d i n streams i n t h e C h i l l i w a c k v a l l e y a r e a . ed w i n t e r the  Due t o t h e absence o f a p r o l o n g -  snowpack a t Haney, t h e r e would be no such c o n t r i b u t i o n o f n i t r a t e t o  streams.  V a r i a t i o n with  discharge  N i t r a t e and ammonium c o n c e n t r a t i o n s were g e n e r a l l y n o t s i g n i f i c a n t l y to discharge  although  some d e c r e a s e s  d i s c h a r g e were o b s e r v e d  related  i n t h e i r concentrations with i n c r e a s i n g  ( F i g u r e s 4.44 and 4.45).  During  a storm event,  nitrate  c o n c e n t r a t i o n s i n c r e a s e d w i t h i n c r e a s i n g d i s c h a r g e i n stream A ( F i g u r e 4.47). The  v a r i a b l e behaviour  o f n i t r a t e i s s i m i l a r t o t h a t found  elsewhere  and may be e x p l a i n e d i n t h e same way as potassium's b e h a v i o u r ,  (Table 4.14),  d i s c u s s e d above  Figure 4.44  'AMMONIUM,  Relationships between streamwater ammonium concentrations and discharge.  CONCENTRATION  VERSUS DISCHARGE.  STREftl A  . EEFORE ClEfKCUIIING • BflER CLEPRCU1TING  —  V  S.5  1 •  13.0  "  1  I  1—•  19.5  "  26.0  1  32.5  1  39.0  DISCHARGE (LITRES/SEC) AMMONIUM CONCENTRATION VERSUS DISCHARGE. STREAM 8 . BEFORE CLERRCUTIMG • AFTER CLEflRCunjNG  1 Y = .009891 + .0655(77) (r = .55)  78.0  I 101.0  130.0  156.0  102.0  I 203.0  I 234.0  .13.0  , 4.1 n  , v,.n  , r.c.o  ! 77.o  , nn.o  , 19.0  I  1  I  DISCHARGE (LITRES/SEC) AMMONIUM CONCENTRATION VERSUS DISCHARGE. STREAM C  o.o  i ll.o  r  72.0  i  I  ! no o  nisCHrwcE. iLMRts/seci  No s i g n i f i c a n t r e l a t i o n s h i p s were found f o r streams A and C. Regression i s f o r "before c l e a r c u t t i n g " data only.  154 F i g u r e 4.45  R e l a t i o n s h i p s between streamwater c o n c e n t r a t i o n s and d i s c h a r g e .  NITRATE CONCENTRATION VERSUS  DISCHARGE!  nitrate  STREAM A  . ecro;c curticuniiic I BflCR CIEHSCUTT1NG  i  6.5  i 13.0  i IS.5  i  i  25.0  32.5  39.0  1  1 45.5  1 — S2.0  104.0  1311.0  155.0  182.0  208 0  1 77.0  , — 80 0  DISCHARGE (LITRES/SEC) NITRATE CONCENTRATION VERSUS DISCHARGE. STREAM 8 . BEFORE CIERRCUTTING I UTTER a t f a D J T T l N G  0-0  26.0  52.0  18.0  DISCHARGE (LITRES/SEC) NITRATE CONCENTRATION VERSUS DISCHARGE. STREAM C  — i 22.0  1 1 33.0 -WO DISCHARGE  1 1 ',5.0 GCi.O (LITRES/SEC)  No s i g n i f i c a n t r e l a t i o n s h i p s were found.  155 (P.132).  The behaviour of ammonium i s s i m i l a r to that found elsewhere  (Fisher  et al. , 1968; K e l l e r , 1970a). V a r i a t i o n between watersheds In the undisturbed watersheds, n i t r a t e concentrations were usually highest i n stream A and s i m i l a r i n streams B and C, probably due to the reasons discussed above f o r higher potassium concentrations i n stream A.  There were no obvious  differences i n ammonium concentrations between streams. E f f e c t s of c l e a r c u t t i n g C l e a r c u t t i n g has had no s i g n i f i c a n t e f f e c t on ammonium concentrations (Table 4.12) whereas n i t r a t e concentrations have been increased (Table 4.15) , t h i s increase being 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) i n the case of stream A.  In view of the time l a g o f more than h a l f a year noted by Likens et al., (1970) and Pierce et al. [1912) i  f o r n i t r a t e increases to become apparent, i t may s t i l l  be too soon to observe any major increases.  Table 4.13  Seasonal v a r i a t i o n of dissolved s i l i c a and anion concentrations i n streamwater i n temperate regions  Location  Nitrate  Sulphate  Chloride  Bicarbonate Dissolved silica  Haney  higher i n winter, lower i n summer  higher i n autumn, lower i n winter  autumn maximum, spring -early summer minimum  l a t e summer early autumn maximum winter mini mum  higher i n early autumn , lower i n winter and early spring  low but maximum i n l a t e summer  r x s e s xn  summer maximum, spring minimum  variable  l a t e summer early autumn maximum Zeman (1973) l a t e spring minimum  Seymour watershed, Vancouver  autumn to January maximum, March minimum  cont.  Reference  This  study  T a b l e 4.13 c o n t . Location  Nitrate  Sulphate  Chloride  Bicarbonate Dissolved silica  Brown et 1973  A l s e a b a s i n autumn coastal maximum, Oregon summer minimum H.J. Andrews Experimental Forest, coastal Oregon  al.,  autumn maximum, summer minimum  l a t e summer e a r l y autumn maximum winters p r i n g minimum  Coastal California 1.  l a t e r winter-spring maximum, summer minimum  higher i n autumn, lower i n winter  higher i n autumn, lower i n winter  Sagahen Ck., Eastern Califor-  Fredriksen, 1971 and 1972  Baldwin, 1971  relatively constant but h i g h e r in late autumn  Coastal California 2.  Reference  higher i n autumn, lower i n winter  Steele, 1968  autumn maximum, spring minimum  Johnson and Needham, 1966  nia Ohio  -  Maryland  autumn maximum, summer minimum  relatively constant  -  -  T a y l o r et 1971  al.,  relatively constant  l a t e summer early autumn maximum l a t e winter minimum  autumn Cleaves maximum, et al., l a t e w i n t e r 1970 minimum  relatively constant  l a t e summer early autumn maximum winterspring minimum  l a t e summer F i s h e r et e a r l y a u t - al., 1968; umn maximum L i k e n s et spring al., 1970 minimum  Hubbard Brook, New Hampshire  s p r i n g maxi-- autumn mum, summer-- maximum, autumn mini- • s p r i n g mum b e f o r e minimum cutting; autumn maximum, s p r i n g minimum after cutting  Review o f results obtained throughout the U.S.  higher i n winter, lower i n summer  Agricultura l watersheds, Norfolk, Britain  l a t e autumn maximum, summer minimum  autumn maximum, summer minimum  relatively constant  Finland  winter maximum, spring minimum (for nitrogen)  autumn maximum, summer minimum  relatively constant but h i g h e r i n autumn  Cleaves  et al., 1970  variable  autumn maximum, winterspring minimum  Edwards, 1973a  large f l u c - Viro, tuations 1953 but h i g h e s t in s p r i n g  157  T a b l e 4.14  V a r i a t i o n o f d i s s o l v e d s i l i c a and a n i o n c o n c e n t r a t i o n s i n streamwater i n t e m p e r a t e . r e g i o n s w i t h i n c r e a s i n g stream d i s c h a r g e  Location  Nitrate  Sulphate  some increases some decreases  no s i g n i f i - no s i g n i f i - d e c r e a s e s cant r e l a - c a n t r e l a tionship tionship  decreases  T h i s study  decreases  decreases  Fredriksen, 1971 and 1972  Haney  Chloride  H.J. Andrews Experimental Forest, Coastal Oregon Western California  Bicarbonate Dissolved silica  some increases, some decreases  Coastal California  Baldwin, 1971  decreases  decreases  decreases  —  —  —  decreases  Western Montana  increases  some increases, some decreases  decreases  decreases  Northern Utah  no s i g n i f i cant r e l a tionship  -  —  decreases  Ohio  no s i g n i f i cant r e l a tionship  -  -  Sagahen Ck. Eastern California  Maryland  Hubbard Brook, New Hampshire  increases  increases  decreases slightly  some increases, some decreases  Reference  decreases  no s i g n i f i - S t e e l e , c a n t r e l a - 1968 tionship  —  Johnson and Needham, 1966 W e i s e l and Newell, 1970  —  Johnston and Doty, 1972 Taylor  •  -  et al., 1971  decreases  Cleaves  et al., 1970  no s i g n i f i - d e c r e a s e s cant r e l a (inferred tionship from decreases i n pH)  decreases  Johnson  et al., 1969  Switzerland decreases  decreases  increases decreases but not significant statistically  no s i g n i f i - K e l l e r , c a n t r e l a - 1970a and tionship b  A g r i c u l t u r - increases a l watersheds, Norfolk, Britain  increases  decreases  Edwards, 1973a and b  158 The  Hubbard Brook workers have found g r e a t l y i n c r e a s e d n i t r a t e  t r a t i o n s f o l l o w i n g c l e a r c u t t i n g i n New g r e a t e r the  concen-  Hampshire w i t h c o n c e n t r a t i o n s  second y e a r a f t e r c u t t i n g than the f i r s t  being  (Hornbeck et al.,  1973;  P i e r c e et al. , 1972).  A l t h o u g h n i t r a t e c o n c e n t r a t i o n s were not measured i n  streams D and  c l e a r c u t t i n g , a n o t i c e a b l e i n c r e a s e i n these  E before  tions occurred  concentra-  i n b o t h streams the second y e a r a f t e r c l e a r c u t t i n g (Table 4.15).  S e v e r a l s t u d i e s i n c o a s t a l Oregon have a l s o r e c o r d e d  i n c r e a s e d n i t r a t e con-  c e n t r a t i o n s i n streams f o l l o w i n g a v a r i e t y of commerical l o g g i n g t r e a t m e n t s i n c l u d i n g c l e a r c u t t i n g (Brown et al., 1973).  Invariably  found i n New  1973;  F r e d r i k s e n , 1971;  F r e d r i k s e n et  however, t h e i n c r e a s e s were much l e s s d r a s t i c t h a n  Hampshire.  C l e a r c u t t i n g i n New  Hampshire was  those  a l s o found t o  the s e a s o n a l v a r i a t i o n o f n i t r a t e c o n c e n t r a t i o n s w i t h maximum  al.,  alter  concentrations  o c c u r r i n g i n e a r l y autumn i n s t e a d of i n s p r i n g , as b e f o r e c u t t i n g , and minimum concentrations  o c c u r r i n g i n l a t e s p r i n g i n s t e a d of i n l a t e summer-early autumn  (Likens et al.,  1970;  P i e r c e et al.,  of n i t r a t e concentrations F r e d r i k s e n et al. concentrations those  1972).  i n New  to a less favourable Hampshire.  Hampshire l i t t e r  favourable microclimate  cm  i n thickness  The  climate causing  less  decomposition of  litter,,  Thus, r e l a t i v e l y more n u t r i e n t s can once c l e a r c u t t i n g has  f o r decomposition.  The  provided  s o i l s i n t h e H.J.  be  a more  Andrews  Ex-  F o r e s t i n Oregon have v e r y t h i n f o r e s t f l o o r s r a n g i n g up t o o n l y  v a r y from 3 t o 18 1962).  variation  Hamsphire, compared t o  T h i s a l l o w s a g r e a t e r b u i l d up  and hence n u t r i e n t s , t h a n i n Oregon. r e l e a s e d from t h e New  seasonal  i n streamwater were found i n the Oregon s t u d i e s .  i n streams f o l l o w i n g c l e a r c u t t i n g i n New  of forest l i t t e r  2.5  changes i n the  (1973) have proposed t h a t t h e g r e a t e r i n c r e a s e s i n n i t r a t e  i n Oregon, aire due  perimental  No  cm  (Rothacher et al.,  1967), whereas those  a t Hubbard Brook  i n t h i c k n e s s w i t h an average o f about 8 cm  s o i l s a t Haney  (Hart et  (Appendix I I ) are more s i m i l a r t o those  al.,  a t Hubbard  159  Table 4.15  Average concentrations of dissolved s i l i c a and anions i n streamwater before and a f t e r c l e a r c u t t i n g . Cl  N0_  S0„  HCO„  SiO„  .97(.23) .97(.20)  .40(.21) .68 (.17)  1.9(.6) 1.6(.6)  7.1(1.1) 5.6(.9)  5.7(1.2) 5.0(1.1)  .77(.22) .76(.21)  .20(.32) .09(.07)  1.8(.8) 1.4(.5)  6.6(1.2) 6.2(1.3)  4.5(.7) 4.0(.9)  .80(.37) .96(.31)  .18(.33) .11(.10)  2.K.8) 2.0(.8)  6.7(1.6) 5.8(1.5)  4.5(1.3) 4.0(1.3)  .83(.34) .85(.25)  .18(.30) .08(.08)  1.9(.8) 1.7(.7)  7.4(2.3) 6.9(2.3)  4.5(1.1) 4.0(1.3)  .64(.32) .79(.30) .76(.16)  .14(.14) .29(.56)  2.2(.5) 2.9(.9)  8.1(6.1) 10.4(4.4)  5.2(1.5)  3  1. Stream A before after  4  3  2  control(C) before after  2. Stream B before after  control(C) before after  3. Stream D before after(l) after(2)  Stream E before after(l) after(2)  control(C) before after(l) after(2)  -  -  1.04(.40) 1.12(.19)  .81 (.41)  .22(.26) .36(.71)  -  3.0(.7) 4.4(.9)  12.2(9.4) 15.4(7.1)  4.3(2.6) 7.6(1.8)  -  .80(.13) .73(.34) .79(.21)  .19(.22) .14(.20)  1.9(.6) 2.2(.8)  8.1(5.8) 11.0(3.5)  4.4(2.2) 5.9(1.7)  A l l concentrations are i n m g / l i t r e *  Standard deviations are given i n parentheses Values are f o r the same periods as i n table 4.12 (p. )  Brook, p a r t i c u l a r l y with respect to f o r e s t f l o o r depth.  In view of  the behaviour of streams D and E a f t e r c l e a r c u t t i n g , i t i s l i k e l y that the streams a t Haney w i l l respond to c l e a r c u t t i n g more l i k e those i n  160 Oregon than those at Hubbard Brook. by Fredriksen et al.  This suggests that the explanation given  (1973) f o r streamwater  n i t r a t e behaviour i s not completely  correct. The large increases i n n i t r a t e concentrations i n streams found i n New Hampshire may be associated with the predominantly deciduous forest cover.  The  l i t t e r from deciduous hardwoods i s r e l a t i v e l y r i c h , promoting b a c t e r i a l a c t i v i t y , and i n p a r t i c u l a r , the a c t i v i t y of n i t r i f y i n g b a c t e r i a .  A more favourable  microclimate following c l e a r c u t t i n g , together with an increased energy source and decreased i n h i b i t i o n of chemoautotrophic bacteria by vegetation i n New Hampshire stimulated the n i t r i f y i n g bacteria which were present i n s u f f i c i e n t quantities to produce large amounts of n i t r a t e which were ultimately washed into streams.  The Oregon watersheds were characterized by a predominantly coniferous  f o r e s t cover whose l i t t e r i s l i k e l y to be more a c i d i c and not as r i c h as that found i n deciduous forests (Rodin and B a z i l e v i c h , 1965).  Such l i t t e r conditions  would not promote n i t r i f y i n g bacteria to the same extent as the hardwood forest litter.  A lower population of n i t r i f y i n g bacteria i n the Oregon s o i l s , i f i t  occurred, could explain the lower n i t r a t e concentrations i n streams observed there. In addition, nutrient fluxes i n the Hubbard Brook hardwood forest are  ecosystems  probably greater than those i n the Oregon ecosystems where the s o i l s  may  have fewer a v a i l a b l e nutrients and, due to the coniferous vegetation, fewer nutrients would be c i r c u l a t i n g .  Interruption of the nutrient cycle would then  allow a r e l a t i v e l y greater loss of nutrients from the Hubbard Brook than from those i n Oregon.  ecosystems  Furthermore, the solution percolating through  soil  i n New Hampshire i s a weak s u l p h u r i c - n i t r i c acid mixture which has a stronger leaching p o t e n t i a l , as discussed i n the following chapter, than the carbonic acid solution which percolates through coastal Oregon, Washington, and B r i t i s h Columbia  ecosystems.  No increases i n ammonium concentrations were found a f t e r forest cutting  161  and herbicide application at Hubbard Brook (Likens et at., 1970) although i n creases were detected a f t e r c l e a r c u t t i n g and slashburning i n Oregon (Fredriksen, 1971).  In the Oregon study, ammonium concentrations immediately follow-  ing burning were s i g n i f i c a n t but f o r the rest of the time they were quite low and one year l a t e r they were n e g l i g i b l e .  The increased ammonium concentrations  in Oregon r e l a t i v e to those at Hubbard Brook following forest removal may be related to the slashburning treatment  i n Oregon or may be due to more anaerobic  conditions i n the Oregon stream which would i n h i b i t the oxidation of ammonium to n i t r a t e , although the l a t t e r seems rather u n l i k e l y . The absence o f abnormally high n i t r a t e and ammonium concentrations i n streams D and E following c l e a r c u t t i n g , r e l a t i v e to those i n undisturbed streams, suggests that c l e a r c u t t i n g w i l l not d r a s t i c a l l y a f f e c t the concentrations o f either of these ions i n streams a t Haney. 6)  Bicarbonate The a n a l y t i c a l method used determined  a l k a l i n i t y and not bicarbonate.  At  the pH of the samples, the predominant carbon species contributing to a l k a l i n i t y w i l l be the bicarbonate ion.  However, bicarbonate concentrations calculated  from the t i t r a t i o n r e s u l t s w i l l be too high for two reasons.  F i r s t l y , although  contributions of orthophosphate ions and aluminium hydroxide complexes are l i k e l y to be n e g l i g i b l e , undissociated carbonic acid together with lesser amounts of organic and s i l i c i c acids are present i n solution and w i l l contribute to a l k a l i n i t y  (Hem, 1970).  Secondly, the a n a l y t i c a l method involved a  t i t r a t i o n to a f i x e d endpoint of pH 4.5 according to the recommended procedure. This, however, neglects the e f f e c t s of i o n i c strength and the reagents used (Barnes, 1964).  Several accurate potentiometric t i t r a t i o n s were c a r r i e d out  and y i e l d e d endpoints varying from pH 4.9 to pH 5.7.  The bicarbonate concen-  t r a t i o n s from these accurate t i t r a t i o n s ranged from 60 to 80% of the concentrations obtained from the standard procedure  (Appendix VI).  Due to time l i m i t a -  tions and to be able to compare the r e s u l t s of t h i s study to those of others,  .162 the s t a n d a r d a n a l y t i c a l method was  used f o r b i c a r b o n a t e  Even a l l o w i n g f o r a r e d u c t i o n o f about 30% g i v e n , b i c a r b o n a t e was (Appendix V ) . the s i l i c a  Although  i n the b i c a r b o n a t e  values  the most common a n i o n p r e s e n t i n streams a t Haney  silica  c o n c e n t r a t i o n s a r e sometimes h i g h e r , most o f  i s p r o b a b l y not p r e s e n t i n a n i o n i c form, as d i s c u s s e d below.  carbonate Hem,  still  analyses.  i s u s u a l l y the most abundant a n i o n i n f r e s h waters  (Gorham,  Bi-  1961;  1970).  Seasonal  behaviour  Bicarbonate  c o n c e n t r a t i o n s f o l l o w e d the s e a s o n a l t r e n d s o f most o f the  o t h e r i o n s i n t h a t c o n c e n t r a t i o n s peaked d u r i n g the low summer and  flow periods of  e a r l y autumn then d e c l i n e d t o minimum v a l u e s d u r i n g the  late  winter  ( F i g u r e 4.46). The water pH  amount o f b i c a r b o n a t e i n streamwater depends l a r g e l y on the and  the amount o f b i o l o g i c a l a c t i v i t y .  stream-  Carbon d i o x i d e from the a t -  mosphere and b i o l o g i c a l a c t i v i t y d i s s o l v e s i n water y i e l d i n g a v a r i e t y o f s p e c i e s depending on the pH o f t h e s o l u t i o n . and  i n c r e a s e d streamwater pH  bicarbonate i n solution. l o g i c a l a c t i v i t y and  Low  Increased b i o l o g i c a l  activity  i n summer both tend t o i n c r e a s e the amount o f carbon  d i o x i d e p r o d u c t i o n from d e c r e a s e d  bio-  l a r g e c o n t r i b u t i o n s o f more a c i d i c t h r o u g h f a l l and  soil  water t o streams i n w i n t e r b o t h a c t t o lower b i c a r b o n a t e c o n c e n t r a t i o n s . T h i s seasonal behaviour  of b i c a r b o n a t e agrees w e l l w i t h t h a t found i n  o t h e r s t u d i e s (Table 4.13). V a r i a t i o n with  discharge  Bicarbonate ( F i g u r e s 4.47 decreases t h a t found  and  c o n c e n t r a t i o n s tended 4.48).  to decrease  with increasing discharge  T h i s w i l l be due p a r t l y t o d i l u t i o n and p a r t l y  i n pH w i t h i n c r e a s i n g d i s c h a r g e .  T h i s behaviour  i s identical  to to  i n o t h e r s t u d i e s (Table 4.14).  V a r i a t i o n between streams Bicarbonate  c o n c e n t r a t i o n s were s i m i l a r i n streams A, B, and C  although  F i g u r e 4.46  20  T  16-  Streamwater bicarbonate concentrations - streams A, B, and C  ALKALINITY AS BICARBONATE R  STREAM A  B  STREAM B  C  STREAM C  clearcutting-  clearcutting>  B  128-  4 Q  llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllN  ONDJFMRMJJRSONDJFMflMJJflSONDJFMRMJJflSONDJFMfl  1970  1971  1972  1973  1974  164  Figure 4.47  Streamwater dissolved s i l i c a and anion concentrations during a storm event (27-29 November, 1973)  STREAM A  Concentration (mg/1)  Si02  5.0  Discharge (litres/sec) 150 50  Ho 28  Concentration 5.0  (mg/1)  STREAM B  Discharge (litres/sec)  27  r  1000 .  r  500  28  I  A l l N 0 concentrations <0.09 mg/1 3  Concentration  (mg/1)  STREAM C  5.0 \ 4.0 3.0 -I  Discharge (litres/sec) r500  2.0  f-300  1.0 H  100 27  28  '  29  A l l N O 3 concentrations <0.09 mg/1 For the three streams a l l H P 0 2  4  concentrations <0.01 mg/1  Figure 4.48 Relationships between streamwater bicarbonate concentrations and discharge. • ALKflLINMT AS BICARBONATE Y&R5U5 DISCHARGE. .  BEFCKE  STREAM A  CI.EFI«:.UMISS  • BFTER CLCPRCuniNG  Y = 11.98 - 4.1651ogX (r = .87)  6.5  -1  —1  19.5  1  ?5.0  1  32.5  1  39.0  DISCHARGE (LITRES/SEC) ALKALINITY AS BICARBONATE VERSUS DISCHARGE. STREAM B 13.0  . BEFORE ClEflRCUniNG f RFTER CLEBRCUrTING  Y = 12.02 - 3.5361ogX (r = .88)  78.0  104.0  130.0  156.0  DISCHARGE (LITRES/SEC) ALKALINITY AS BICARBONATE VERSUS DISCHARGE. STREAM C  208.0  Regressions are f o r "before c l e a r c u t t i n g " data only.  234.0  166  maximum concentrations i n C tended to be higher than those i n A and B (Figure 4.46). E f f e c t s of c l e a r c u t t i n g C l e a r c u t t i n g has i n i t i a l l y decreased bicarbonate concentrations 4.15), t h i s decrease being s t a t i s t i c a l l y s i g n i f i c a n t only (Appendix X). ing  clearcutting.  (Table  (P<0.10) f o r stream A  This i s probably associated with the decreased pH followDuring the warmer months, b i o l o g i c a l a c t i v i t y i s l i k e l y to  be enhanced by the more favourable microclimate and the increased abundance of material f o r decomposition.  The r e s u l t i n g increased carbon dioxide production  would have the opposite e f f e c t on bicarbonate concentrations to that of decreased streamwater pH.  The net r e s u l t of t h i s i s not yet completely  clear.  However, i t i s noteworthy that, despite lower pH values i n streams D and E following c l e a r c u t t i n g , rather high bicarbonate concentrations have been measured during the summer whereas winter concentrations are s i m i l a r to those i n streams A, B, and C (Figure 4.49). Forest c u t t i n g and herbicide a p p l i c a t i o n at Hubbard Brook decreased streamwater bicarbonate concentrations due to a decrease 1970).  3  On the other hand, c l e a r c u t t i n g i n Oregon tended to increase bicarbon-  ate concentrations, but no changes i n pH were observed 7)  i n pH (Likens et dl.  (Fredriksen, 1971).  Dissolved s i l i c a  Seasonal  variation  Although  the i n i t i a l s i l i c a concentrations were widely scattered and are  f e l t to be inaccurate due to inconsistent a n a l y t i c a l procedures associated with the tendency of dissolved s i l i c a to s e t t l e to the bottom of sample cont a i n e r s , concentrations tended to be lower i n winter and early spring and higher i n e a r l y autumn (Figure 4.50).  This seasonal behaviour agrees well  with that found i n other studies (Table 4.13). Most of the s i l i c a dissolved i n streamwater comes o r i g i n a l l y from weathering  of mineral p a r t i c l e s and w i l l be present predominantly  i n the form of  F i g u r e 4.49  40  T  Streamwater bicarbonate concentrations - streams D and E  flLKRLINITY c D  32 •• E  STREAM C STREAM D STREAM E Felling  24-  RS BICARBONATE  i"  I  Yarding  168-  0  IIIHIMIIIIIIIIIMIIIIIIIIIHnilllllllHIilllllllHIIIMIinnMllllllMHHMUIIIIiHIIIIIIIHHIIIMIIIIIIIIHIIIIIIIllllllll  ONDJFMflMJJflSQNDJFMflMJJRSONDJFMRMJJflSQNDJFMR  1970  1971  1972  1973  1974  168  s i l i c i c a c i d at the pH of the streams, rather than as s i l i c a t e anions 1970).  (Hem,  Weathering of minerals i s l i k e l y to be most active i n the warmer months  when the weathering products w i l l accumulate during dry periods. These products w i l l be flushed away by the autumn r a i n s , accounting f o r increased concentrations during e a r l y autumn. V a r i a t i o n with discharge Dissolved s i l i c a concentrations decreased with increasing discharge (Figures 4.47 and 4.51) which agrees with r e s u l t s from some other studies (Table 4.14).  The v a r i a b l e r e l a t i o n s h i p s reported between dissolved s i l i c a  concentrations and discharge may be due to concentrations increasing with i n creasing discharge following r a i n s a f t e r periods of active weathering i n warmer months and concentrations decreasing with increasing discharge during the colder months as p r e c i p i t a t i o n d i l u t e s the streamwaters. V a r i a t i o n between streams Dissolved s i l i c a concentrations tended to be highest i n stream A and s i m i l a r i n streams B and C (Figure 4.50). weathering i n watershed A.  This suggests a greater amount of  The warmer temperatures i n watershed A together  with the exposure o f much mineral s o i l to the atmosphere i n the 1961 plantat i o n which covers 31% of watershed A (Figure 2.3) are l i k e l y to be major cont r i b u t i n g factors to the higher q u a n t i t i e s of s i l i c a i n stream A. E f f e c t s of c l e a r c u t t i n g Clearcutting has had v i r t u a l l y no e f f e c t on dissolved s i l i c a  concentra-  tions i n streams A and B (Table 4.15; Appendix X ) . Increases are only expected  i f mineral weathering rates are increased,  and this- i s only l i k e l y to occur during the warmer months.  Data has, so f a r ,  only been c o l l e c t e d f o r the colder months following c l e a r c u t t i n g , so i t i s s t i l l too e a r l y to draw  any conclusions.  In addition to changes i n weathering rates, changes i n pH can also a f f e c t the concentrations of s i l i c a i n s o l u t i o n .  At the r e l a t i v e l y low temperatures  F i g u r e 4.50  Streamwater d i s s o l v e d  s i l i c a concentrations - streams A, B, and C  DISSOLVED SILICA  15T  R  12.5-  = STREAM R  B -  STREAM B  C -  STREAM C  clearcutting-  clearcuttingB  10 7.552.5Q  1  1111 [ I i E1111111111 i 11  ) 11111 r 111111 i 111111 ] i 111M111111111111L11L111U111111111T M L1111 i i 11111 i I i I i i 11L L11L1 i 11111111T f i  ONDJFMRMJJflSONDJFMRMJJRSONDJFMRMJJflSONDJFMR  1970  1971  1972  1973  1974  Figure 4.51 Relationships between streamwater d i s s o l v e d s i l i c a concentrations and discharge. 0ISS0LVE0 SILICA  VERSUS D I S C H A R G E .  STREAM A  . BtfoHC c i E w c u r n n c • wIEH c u t t c u r r m s  . BEFORE OEflRGinilC  Regressions  are f o r "before c l e a r c u t t i n g " data only.  171 commonly encountered weathering  i n t h e watersheds t h e s o l i d which i s f i r s t  i s amorphous s i l i c a whose s o l u b i l i t y i s i n v e r s e l y r e l a t e d t o pH  between pH3 and 7 ( M a r s h a l l , 1964). ing  formed from  Thus, a d e c r e a s e  i n streamwater pH f o l l o w -  c l e a r c u t t i n g may f u r t h e r i n c r e a s e t h e amount o f s i l i c a g o i n g i n t o Increases  i n dissolved s i l i c a  c o n c e n t r a t i o n s were observed  after  solution. forest  c u t t i n g and h e r b i c i d e a p p l i c a t i o n a t Hubbard Brook b u t i t was more than a y e a r b e f o r e t h e i n c r e a s e s became d i s t i n c t  ( L i k e n s et al., 1970).  I n view o f t h i s ,  i t may be t h a t , i f any s i g n i f i c a n t i n c r e a s e s i n s i l i c a  concentrations are to  o c c u r , i t w i l l be some time b e f o r e they a r e m a n i f e s t .  T h i s time l a g may be  a s s o c i a t e d w i t h i n c r e a s i n g exposure o f t h e s o i l  s u r f a c e caused  by decay o f  p r o t e c t i v e s l a s h o r may be due t o t h e n e c e s s i t y f o r a c o n s i d e r a b l e amount o f e x t r a weathering  products  t o accumulate b e f o r e changes i n stream  silica  con-  c e n t r a t i o n s become n o t i c e a b l e . 8)  Sulphate Sulphur  and  i n aqueous s o l u t i o n which has a h i g h d i s s o l v e d oxygen  n e a r - n e u t r a l pH v a l u e s w i l l o c c u r almost  e n t i r e l y as s u l p h a t e  content anions  (Hem, 1970). Seasonal  behaviour  Sulphate  c o n c e n t r a t i o n s f l u c t u a t e d c o n s i d e r a b l y so t h a t no c l e a r  a l t r e n d s were apparent. tumn and lower  i n winter  However, c o n c e n t r a t i o n s tended  season-  t o be h i g h e r i n au-  ( F i g u r e 4.52) , which agrees w e l l w i t h t h e r e s u l t s o f  o t h e r s t u d i e s (Table 4.13). The  observed  f l u c t u a t i o n s were p r o b a b l y due t o poor r e s o l u t i o n i n t h e  a n a l y t i c a l technique  as w e l l as t o t h e f a c t t h a t t h e measured c o n c e n t r a t i o n s  a r e c l o s e t o t h e d e t e c t i o n l i m i t o f t h e a n a l y t i c a l method used. t i o n data presented V a r i a t i o n with Sulphate  are probably  t o o h i g h , as d i s c u s s e d above  The c o n c e n t r a -  (P. 127).  discharge c o n c e n t r a t i o n s g e n e r a l l y were n o t s i g n i f i c a n t l y r e l a t e d t o  discharge, although  some i n c r e a s e s w i t h i n c r e a s i n g d i s c h a r g e were  ( F i g u r e s 4.47 and 4.53).  The v a r i a b l e b e h a v i o u r  observed  of sulphate concentrations  F i g u r e 4.52  Streamwater sulphate  concentrations  - streams A, B, and C  SULPHATE R = S T R E A M fl  . A  .  clearcutting-  ,  B = STREAM B  4 1 c =S T R E A M  clearcutting-  a  ,  C  32• 1 Q  IIIIIMMnilMIIIIIIIMl'llllHMMIItlllllllllMlllllllllHllinilllinHinilllMllllllill4Mllin  ONDJFMflMJJflSONDJFMRMJJflSONDJFMflMJJflSONDJFMfl  1970  1971  1972  1973  1974  F i g u r e 4.53  R e l a t i o n s h i p s between streamwater s u l p h a t e c o n c e n t r a t i o n s and d i s c h a r g e .  SULPHATE CONCENTRATION VERSUS Olf-OinRGC.  STREAM A  . FEfiVf C'. !l-CUtt!)«G r  c uniF  curjcjrtjNG  1 6.5  1 13.0  1 19.5  1 25.0  DISCHARGE  1 32.5  1 39.0  :  1 45.5  1 52.0  1 58.5  1 182.0  1 203.0  1 234.0  (LITRES/SEC)  SULPHATE CONCENTRATION VERSUS DISCHARGE.  STREAM B  . BEFORE CIEPRCUTTISC • RfTER C L E f l S C u m . i S  I  I 26.0  52.0  1 18.0  1 104.0  0ISCHRRGE  1 130.0 (LITRES/SEC)  SULPHATE CONCENTRATION VERSUS DISCHARGE.  -1 11.0  :  i  22.0  i 3) 0  No s i g n i f i c a n t  1  1 156.0  1  STREAM C  1  . u p v. n i.s n O l S C t i t ^ G K tLUKtS/StC!  1— 17 0  r e l a t i o n s h i p s were f o u n d .  1 65.0  174 with discharge reported i n other studies (Table 4.14)  may  depend on the amount  of sulphate i n p r e c i p i t a t i o n , with high sulphate concentrations i n p r e c i p i t a t i o n causing increases i n sulphate concentrations as streams r i s e and low concentrations i n p r e c i p i t a t i o n causing decreases.  Sulphate concentrations i n  p r e c i p i t a t i o n at Haney are r e l a t i v e l y high, as discussed i n chapter f i v e . V a r i a t i o n between streams There are no obvious differences i n sulphate concentrations between the three streams (Figure 4.52).  This may  r e f l e c t the over-riding influence of  concentrations i n p r e c i p i t a t i o n on streamwater concentrations. E f f e c t s of c l e a r c u t t i n g Clearcutting has caused s l i g h t but s t a t i s t i c a l l y i n s i g n i f i c a n t increases i n sulphate concentrations i n both streams A and B (Tabel 4.15,  Appendix X).  Forest cutting and herbicide a p p l i c a t i o n at Hubbard Brook decreased sulphate concentrations i n streamwater (Likens et aZ.,,1970) as d i d commercial clearcutting  (Pierce et al.  s  1972).  The decrease i n sulphate concentrations  was explained by large increases i n n i t r a t e concentrations i n the s o i l which are toxic to sulphur o x i d i z i n g b a c t e r i a .  Since i t i s u n l i k e l y that there w i l l  be such a large increase i n n i t r a t e concentrations at Haney, (as discussed above), decreases i n sulphate concentrations i n streams are equally u n l i k e l y . Although sulphate concentrations were not measured i n streams D and E p r i o r to c l e a r c u t t i n g , no abnormally high or low post-logging concentrations have been observed.  This suggests that any changes i n sulphate concentrations, as  a r e s u l t of c l e a r c u t t i n g , w i l l be rather small. 9)  Chloride  Seasonal  behaviour  Chloride concentrations exhibited pronounced seasonal trends with maximum values i n autumn and minimum values i n spring and early summer (Figure 4.54). These trends d i f f e r from those found by most other workers although they are similar to those found by Zeman (1973) i n a stream 60 km.  from the Haney  F i g u r e 4.54  4T  Streamwater c h l o r i d e concentrations - streams A, B, and C  CHLORIDE fl  STREAM A  B  STREAM B  C  STREAM C  clearcuttingA clearcuttingB  I  2.90 -  1  2.181 .45 .7270  111 llllll lltlftt IJftl-flllllif fltlll IIIIIII Jlllll Itlllll lltltt illillf llllfl lt<-l<t< llllll IIIIIIIfflltlfIIIIIII Iflllt l<<<<-*t41<4li  ONDJFMflMJJflSONDJFMflMJJflSONDJFMflMJJflSONDJFMfl  1970  1971  1972  1973  1974  176  watersheds (Table 4.13). Igneous rocks, such as those which form the bedrock of the watersheds, contain l i t t l e c h l o r i d e .  Due  to the b i o l o g i c a l i n a c t i v i t y of chloride and  i t s lack of r e a c t i v i t y i n s o i l s , i t i s l i k e l y that most of the chloride i n the streamwater comes from p r e c i p i t a t i o n  (Hem,  1970; Junge and Werby, 1958).  During the dry summer i t has been proposed that most c h l o r i d e i s deposited i n p a r t i c u l a t e form, to be washed away by the autumn rains (Juang and Johnson, 1967).  This would explain the seasonal trends observed at Haney.  V a r i a t i o n with  discharge  Chloride concentrations appear to be independent of discharge at Haney (Figures 4.47  and 4.55)  (Table 4.14).  This may  i n agreement with the findings of most other workers be p a r t l y due to the v a r i a b l e nature of chloride con-  centrations i n p r e c i p i t a t i o n , which are higher when the p r e v a i l i n g winds come d i r e c t l y from the sea.  I t may  also be p a r t l y due to the i n e r t nature of  chloride ions which tend to pass through an ecosystem without many reactions. V a r i a t i o n between streams There were no obvious differences i n c h l o r i d e concentrations between the three streams (Figure 4.54).  This i s expected i f the source of most of the  chloride i s p r e c i p i t a t i o n . E f f e c t s of c l e a r c u t t i n g C l e a r c u t t i n g has caused a very s l i g h t increase i n chloride concentrations i n stream A but pronounced increases i n streams B, D, and E, which were s t a t i s t i c a l l y significant  (P<0.01) i n the case of stream E (Table 4.15; Appendix X).  The e f f e c t of c l e a r c u t t i n g on chloride concentrations was Oregon.  not studied i n  At Hubbard Brook, however, f o r e s t c u t t i n g and herbicide a p p l i c a t i o n  increased c h l o r i d e concentrations, the increase being greatest the f i r s t a f t e r c u t t i n g (Likens et at., f o r stream D. stream A may  1970), as has been found i n the present  year  study  This suggests that any increases i n c h l o r i d e concentrations i n be most noticeable i n the autumn of  1974.  177  Figure 4.55 Relationships between streamwater c h l o r i d e concentrations and discharge. • C H L O R I D E CONCENTRATION V E R S U S D I S C H A R G E .  STREAM A  0 WTLR t L C W t t i t T I n S  0C  3 o  §20.0  —I— 6.S  13.0  — i —  19.5  26.0 J2.5 39 0 DISCHARGE (LITRES/SEC) C H L O R I D E CONCENTRATION V E R S U S D I S C H A R G E . STRESM 3  38.5  -1 65.0  o BfUR c u f t j o i r r i i i s  OJt  2S.0  52.0  1  —I  1B.0  1  T  104.0  130.0  — —  iss.o  182.0  —TT 204.0  234.0  260.0  DISCHARGE ( L I T R E S / S E C J CHLORIDE CONCENTRATION V E R S U S D I S C H A R G E . STREAM C  3 O  -1 11.0  1 22.0  1— 13.0  1 +4.0  DISCHARGE  1 55  1 0  ILJIRES/SEC)  66 0 '  No s i g n i f i c a n t r e l a t i o n s h i p s were found.  —I 110.0  178 10)  Phosphate Phosphate concentrations have remained undetected v i r t u a l l y throughout  the entire sampling period.  Phosphate i n unpolluted streams i s u s u a l l y found  at extremely low concentrations, t h i s being attributed to the u t i l i z a t i o n of phosphorus by aquatic vegetation and the adsorption of phosphate ions by metal oxides, e s p e c i a l l y f e r r i c hydroxide  (Hem,  1970).  Any phosphorus present i n  streamwater at Haney, however, would e x i s t predominantly phosphate anions  as dihydrogen  (H P0^) i n view of the pH of the solutions (Hem,  1970) .  2  Although phosphate concentrations have been reported to decrease increasing discharge  ortho-  with  [and to be lower i n spring and higher i n autumn (Edwards,  1973a and b; Johnston and Doty, 1972)J, concentrations i n streams at Haney have been too low to permit such observations. E f f e c t s of c l e a r c u t t i n g Phosphate concentrations i n a l l streams have remained too low to permit any meaningful conclusions to be drawn. Brown et at.,  (1973) found no changes i n phosphate concentrations follow-  ing c l e a r c u t t i n g and slashburning i n the Alsea basin i n Oregon.  Although  Fredriksen (1971) also observed no changes i n stream phosphate concentrations following c l e a r c u t t i n g , he did observe an increase following slashburning. The concentrations measured i n both these studies are close to the detection l i m i t of the a n a l y t i c a l method used i n t h i s study and consequently  any such  changes would be d i f f i c u l t to detect at Haney. 8.  Chemical budgets Monthly chemical inputs of selected nutrient chemicals were determined  for each watershed by m u l t i p l y i n g monthly amounts of p r e c i p i t a t i o n by monthly average chemical concentrations i n p r e c i p i t a t i o n .  Outputs were determined by  m u l t i p l y i n g volumes of water discharged i n streams per month by monthly average chemical concentrations i n streamwater. by subtracting outputs from inputs.  Net gains or losses were determined  Detailed monthly budgets are given i n  179 Appendix  XIII.  Annual budgets a r e summaried i n T a b l e 4.16.  T h e r e was a n e t l o s s o f c a l c i u m , sodium, and magnesium from a l l w a t e r sheds and p o t a s s i u m and s u l p h u r from a l l watersheds e x c e p t watershed C.  Net  l o s s e s o f p o t a s s i u m and s u l p h u r from watershed C a r e l i k e l y , however, s i n c e the  amount o f water d i s c h a r g e d from watershed C was p r o b a b l y u n d e r e s t i m a t e d  by about 30% (P.76 ) . nor  A l l watersheds accumulated n i t r o g e n b u t n e i t h e r g a i n e d  l o s t phosphorus, as t h e v e r y low phosphorus  The c h l o r i d e b a l a n c e changed net  inputs e q u a l l e d the outputs.  from y e a r t o y e a r w i t h n e t l o s s e s one y e a r and  g a i n s t h e second.  T a b l e 4.16  Annual c h e m i c a l budgets  watershed 1. water 2. water 3.* f i r s t after  A y e a r 1971/72 year 1972/73 s i x months clearcutting  watershed 1. water 2.* f i r s t after  B y e a r 1972/73 s i x months clearcutting  watershed 1. water 2. water 3.* f i r s t after  B + C y e a r 1971/72 y e a r 1972/73 s i x months clearcutting  watershed 1. water 2.* f i r s t after  C y e a r 1972/73 s i x months clearcutting  (kg/ha)  K  Na  Mg  Ca  Cl  -0.8 -0.9  -10.7 -6.3  -3.0 -2.1  -15.9 -10.6  -1.5 +0.6  • +2.6  -0.6  •-  -3.7  -10.1  -2.7  -14.7  -4.6  + 1.6  -3.3  0.0  -1.4  -8.3  -3.7  -17.3  -4.0  +3.3  -7.5  0.0  -8.0  -17.2  -5.5  -24.3  -13.2  +3.3 -10.8  0.0  -0.1 -0.5  -10.5 -5.2.  -3.6 -2.6  -18.6 -13.7  -0.8 +0.7  +3.4  -2.4  0.0  -3.1  -10.7  -3.4  -19.3  -4.8  +3.9  -5.0  0.0  +0.1  -3.5  -1.8  -11.8  +3.3  +3.5  +0.5  0.0  -0.4  -5.6  -2.2  -16.5  -0.1  +4.2  -1.8  0.0  N  -  S  -  P  0.0  -  Water y e a r s are from O c t o b e r 1 s t t o September 3 0 t h . Potassium, sodium, magnesium, c a l c i u m , and c h l o r i n e budgets were d e t e r m i n e d from c o n c e n t r a t i o n s o f t h e i r r e s p e c t i v e i o n s . N i t r o g e n was d e t e r m i n e d from t h e sum o f n i t r a t e - n i t r o g e n and ammonium-nitrogen budgets. S u l p h u r was d e t e r m i n e d from c o n c e n t r a t i o n s o f s u l p h a t e - s u l p h u r . Phosphorus was determined from c o n c e n t r a t i o n s o f phosphate-phosphorus. *These c h e m i c a l budgets a r e f o r a six-month p e r i o d o n l y .  180 E s t i m a t e d e r r o r s i n budget c a l c u l a t i o n s Contamination of p r e c i p i t a t i o n presented a large uncertainty  i n budget  c a l c u l a t i o n s . However, i t was c o n s i d e r e d t h a t pH and p o t a s s i u m  concentra-  t i o n measurements were good i n d i c e s o f t h e p u r i t y o f samples.  When e i t h e r  of t h e s e measurements were a b n o r m a l l y h i g h t h e samples were r e j e c t e d . This minimized t h e c o n t r i b u t i o n The  o f contaminated samples t o b u d g e t s .  e s t i m a t e d maximum e r r o r s i n t h e budget c a l c u l a t i o n s a r e g i v e n i n  T a b l e 4.17.  These e r r o r s were r a t h e r  than f o r i n p u t  - calculations.  l a r g e and were g r e a t e r  f o r output -  E r r o r s i n water volume c a l c u l a t i o n s were  usually greater  than e r r o r s i n chemical c o n c e n t r a t i o n  phur, n i t r o g e n ,  and c a l c i u m b u d g e t s , i n t h a t o r d e r , were c o n s i d e r e d t o be  the  l e a s t accurate.  were d e r i v e d  I t s h o u l d be s t r e s s e d  from s u b j e c t i v e  measurements.  Sul-  t h a t t h e e s t i m a t e d maximum e r r o r s  e s t i m a t e s o f t h e maximum e r r o r s p o s s i b l e f o r  each s t e p i n t h e c a l c u l a t i o n s .  The e s t i m a t e d maximum e r r o r s r e p r e s e n t an  extreme s i t u a t i o n where a l l e r r o r s were c o n s i d e r e d t o a c t i n t h e same d i r e c t i o n , Thus, i t i s u n l i k e l y t h a t t h e r e a l e r r o r s would be as g r e a t . R e l a t i v e l y high errors are involved shed B.  i n budget c a l c u l a t i o n s f o r w a t e r -  These a r i s e m a i n l y from t h e n e c e s s i t y  water f l o w i n g  over two w e i r s , r a t h e r  o f c a l c u l a t i n g volumes o f  than j u s t one.  Thus, t h e e x p e r i m e n t a l  d e s i g n used produces r e s u l t s which a r e much l e s s a c c u r a t e t h a n t h o s e obtained  from a d e s i g n which uses e n t i r e watersheds  only.  I f w e i r C i s u n d e r e s t i m a t i n g s t r e a m f l o w by about 30%, a s seems then chemical losses 30%.  Increasing  likely,  from watershed C would a l s o be u n d e r e s t i m a t e d by about  chemical losses  from watershed C by 30% would produce  c h e m i c a l budgets more s i m i l a r t o t h o s e found f o r watershed A and B + C ) . I t would a l s o reduce c h e m i c a l l o s s e s from watershed B p r o d u c i n g budgets which would a l s o be more s i m i l a r t o t h o s e found f o r watersheds A and (B + C ) .  Table 4.17 a)  Estimated maximum errors i n chemcial budget c a l c u l a t i o n s  Inputs (to a l l watersheds) Total Error  1. 2.  (%) i n  Na  Mg  Ca  C l H^PC^-P  Volume estimation concentration  10 10  10  10  10  measurement  14  cumulative b)  1. 2. 3.  8 9 2 5 9 20  38  20  25 19  i . Watersheds A and (B + C) Error (%) i n K Na Mg  Ca  Cl  NC^-N  NH^-N  s o 4  "  s  10  10  10  -  10  10  8  10  -  45  21  19  21  40  60  Total N  SO -s 4  Outputs  weir c a l i b r a t i o n mean d a i l y height estimation concentration measurement  cumulative ii. 1. 2. 3.  total  K  total  6  H P0 -P 2  4  NO -N  NH -N 4  6  6  6  6  6  6  6  23 23  23  23  23  23  23  23  -  23  8  9  25  9  10  8  10  -  45  48 40  42  62  42  43  40  43  83  89  30 30 34 34  30 34  30 34  30 34  30 34  30 34  30 34  '-  30 34  9  25  9  10  8  10  -  45  88 78  80 106  80  82  78  82  160  139  10 10  10  10  10  10  10  10  —  10  23 23  23  23  23  23  23  23  23  8  9  25  9  10  8  10  -  54 46  47  69  47  49  46  49  95  96  14  6  Watershed B  weir B discharge weir C discharge concentration measurement  cumulative  total  14  8  i i i . Watershed C 1. 2. 3.  weir c a l i b r a t i o n mean d a i l y height estimation concentration measurement  14  O  Budgets (Overall % error = % error i n input + % error i n output)  i.  Watersheds A and B + C  ii.  Watershed B  iii.  Watershed C  73 59  62  64  59  64  123  149  113 97 100 144 100  103  97  103  200  199  • 70  65  70  135  156  79 65  62 100  45  67 107  67  182  Work at Hubbard Brook (Likens et al. 1967) and Coweeta (Johnson and Swank, 3  1971) has established that weekly sampling i s s u f f i c i e n t l y frequent to produce accurate nutrient budgets.  The absence of large d a i l y v a r i a t i o n s i n chemical  concentrations i n streamwater  at Haney, discussed below (P.189 ) suggested that  weekly sampling was also s u f f i c i e n t at Haney. Loss of chemicals bound to s o l i d p a r t i c l e s i n streamwater was considered to be unimportant at Haney i n view of the low suspended measured i n the streams.  sediment concentrations  This was found to be the case at Coweeta where less  than 2% of each of sodium, potassium, magnesium, and calcium was l o s t i n s o l i d form (Johnson and Swank, 1973).  At Hubbard Brook, l e s s than 6% of each of  calcium, magnesium, sodium, nitrogen, and sulphur but 18% of potassium (Bormann et al.  3  1969) and most of the phosphorus  (Hobbie and Likens, 1973) was l o s t i n  s o l i d form. Seasonal trends i n chemical budgets A l l the chemicals considered exhibited s i m i l a r behaviour with outputs i n creased r e l a t i v e to inputs throughout winter and early spring, and inputs i n creased r e l a t i v e to outputs throughout summer and autumn.  Of these chemicals,  potassium, c h l o r i d e , and sulphate exhibited frequent monthly gains during summer and autumn.  Net monthly losses were usually observed throughout the year  for sodium, magnesium, and calcium, whereas the watersheds gained both ammonium and  nitrate  nitrogen v i r t u a l l y every month although the gains were lower  during the summer.  Continual gains i n nitrogen are probably due to b i o l o g i c a l  uptake with a net incorporation of nitrogen i n the f o r e s t biomass. gen may also be l o s t by conversion to gaseous forms  Some n i t r o -  (Wollum and Davey, 1973).  Potassium behaved e r r a t i c a l l y , unlike the other m e t a l l i c cations.  The  gains almost balanced the losses although there was considerable monthly tuation between gains and losses.  fluc-  Also, i n the 1972/73 water year, losses were  greater than i n the 1971/72 water year, despite less p r e c i p i t a t i o n . Such a t y p i c a l behaviour by potassium has been attributed to the f a c t  183  that i t s mineralogical and b i o l o g i c a l r o l e s are d i f f e r e n t from those of the other m e t a l l i c cations (Likens et al.  3  completely  1967).  Chemical weathering does not  release potassium as some ions remain i n clay structures.  Hence,  clay p a r t i c l e s i n the s o i l may act as a r e s e r v o i r of chemically bound potassium. Also, a higher percentage of a v a i l a b l e potassium compared to the other cations may be taken up by organisms so that biomass accumulation,  which was occurring  i n the watersheds as evidenced by the r e l a t i v e l y large width of recent tree growth r i n g s , may allow b i o t a to be a r e s e r v o i r f o r potassium. The seasonal trends i n chemical budgets a t Haney are v i r t u a l l y i d e n t i c a l to those found at Hubbard Brook f o r sodium, magnesium, and calcium al.,  (Likens et  1967), c h l o r i d e (Juang and Johnson, 1967), and sulphate, n i t r a t e , and  ammonium (Fisher et al.  3  1968).  These trends, however, are d i f f e r e n t to those  found a t Seymour where chemical inputs increased r e l a t i v e to outputs the winter but decreased  during  r e l a t i v e to outputs during the summer (Zeman, 1973).  This i s probably due to greater contributions of snowmelt runoff during summer to the stream at Seymour compared to Haney and Hubbard Brook.  At Seymour,  stream discharge exceeded p r e c i p i t a t i o n during summer (Zeman, 1973), unlike the s i t u a t i o n at Hubbard Brook (Likens et al.,  1967), and Haney..  Relationships between chemical loads and water quantities In general, the inputs and outputs of a l l chemicals increased with volume of water.  S t a t i s t i c a l l y s i g n i f i c a n t r e l a t i o n s h i p s were found i n most cases  but the r e l a t i o n s h i p s were i n v a r i a b l y better between chemical outputs and volume o f water discharged than between chemical inputs and volume o f p r e c i p i t a t i o n (Appendix XIV).  This can be a t t r i b u t e d to the highly v a r i a b l e nature  of chemical concentrations i n p r e c i p i t a t i o n which depend on the amount of i n d u s t r i a l a i r p o l l u t i o n and the d i r e c t i o n of the p r e v a i l i n g winds.  These two  factors frequently change and thus a f f e c t the monthly chemical inputs. Logarithmic r e l a t i o n s h i p s between chemical loads and water volumes were found to be i n v a r i a b l y more accurate than l i n e a r r e l a t i o n s h i p s , as has been  SJ  184 found elsewhere  (e.g. Zeman, 1973).  Annual c h e m i c a l budgets f o r f o r e s t - w a t e r s h e d ecosystems ' D e s p i t e t h e p o s s i b i l i t y o f l a r g e e r r o r s i n c h e m i c a l budget c a l c u l a t i o n s , the budgets f o r t h e Haney watersheds a r e q u i t e s i m i l a r t o budgets f o r watersheds elsewhere  i n humid temperate r e g i o n s  (Table 4.18).  They a r e p a r t i c u l a r -  l y s i m i l a r t o those f o r Hubbard Brook. From T a b l e 4.18, c e r t a i n t r e n d s i n annual  c h e m i c a l budgets o f u n d i s t u r b e d  f o r e s t - w a t e r s h e d ecosystems a r e apparent: 1.  There i s a c o n s i s t e n t l o s s o f magnesium, c a l c i u m , and u s u a l l y  2.  There i s a c o n s i s t e n t g a i n o f n i t r o g e n .  3.  Net g a i n s o r l o s s e s o f phosphorus a r e i n v a r i a b l y v e r y s m a l l .  4.  C h l o r i d e , s u l p h u r , and p o t a s s i u m may be g a i n e d o r l o s t b u t t h e s e g a i n s o r  losses are quite small. Seymour  sodium.  The o n l y e x c e p t i o n i s t h e l a r g e c h l o r i d e l o s s  from  (Zeman, 1973).  R e s u l t s from Haney were c o n s i s t e n t w i t h each o f t h e s e t r e n d s . Comparing t h e Haney watersheds t o nearby Jamieson Ck. a t Seymour, i t can be seen t h a t l o s s e s o f a l l c h e m i c a l s , except s u l p h u r , were g r e a t e r , and n i t r o gen a c c u m u l a t i o n  l e s s , a t Seymour.  T h i s was p r o b a b l y due t o a combination o f  the f o l l o w i n g f a c t o r s : 1.  A i r p o l l u t i o n from Vancouver and s u r r o u n d i n g i n d u s t r i a l a r e a s , has i n c r e a s -  ed c h e m i c a l 2.  i n p u t s i n p r e c i p i t a t i o n a t Haney, r e l a t i v e t o Seymour.  The f o r e s t s a t Haney a r e r e l a t i v e l y young and s t i l l  They a r e l i k e l y t o be a c c u m u l a t i n g cals, 3.  accumulating  biomass.  g r e a t e r amounts o f biomass, and hence chemi-  than the v e r y o l d f o r e s t s a t Seymour.  G r e a t e r p r e c i p i t a t i o n a t Seymour  (316 cm f o r t h e 1972/73 water y e a r , com-  p a r e d t o 177 cm a t Haney) and lower e v a p o t r a n s p i r a t i o n (40 cm compared t o about 65 cm a t Haney) causes through  c o n s i d e r a b l y g r e a t e r q u a n t i t i e s o f water to. p a s s  the Seymour watershed.  T h i s i s l i k e l y t o i n c r e a s e t h e amount o f chemi-  c a l s l e a c h e d away r e l a t i v e t o Haney.  T h i s i s supported by  statistically  185 T a b l e 4.18  Annual c h e m i c a l budgets o f u n d i s t u r b e d f o r e s t - w a t e r s h e d ecosystems i n humid temperate r e g i o n s (kg/ha).  Area Haney -  1971/72  average o f watersheds A 1972/73 and (B+C)  Jamieson Creek, 1970/71 Seymour watershed , Vancouver Hubbard Brook, New Hampshire  1963/64 1964/65 1965/66 1966/67 1967/68 1968/69  Cl  N  S  P  Reference  -17.3  -1.2  _  _  _  This  -2.4  -12.2  +0.7  +3.0  -1.5  0.0  -12.4  -6.6  -34.4 -15.0  +0.1  -0.8  -0.1  +0.7 +0.7  -4.9 -2.4  -1.9 -0.7  -5.0 -1.1  -1 -2  -6 -7  -3 -3  -  -1.4  -8 -9  +2 0  +1.8 +4.0 +5 +5  +0.2 -1.5 -3 -3  -  -  K  Na  Mg  -0.5  -10.6  -3.3  -0.7  -5.8  -1.7  -  -  -  -  Ca .  -  -  -  -  +0.1  study  Calculated from d a t a i n Zeman (1973)  Calculated from d a t a in Fisher et al. .,1968; Hobbie and L i k e n s , 1973; Juang and Johnson,1967; L i k e n s et al. 1967; L i k e n s  et  al.,1970.  -2. 2  -4.3  -1.8  -0.8  —  —  -  -  +1.6  +1.1 -46.7  -58.6  -  —  —  —  1966/68 annual average  -0.3  -1.4  -0.7  +0.2  H.J. An- 1969/70 drews Experimen- 1970/71 t a l Forest, Oregon  -1.0  -32.5 -12.0  -46.0  -  +0.5  -  -  -2.1  -23.4 -11.1  -48.0  -  +0.5  -  -0.3  -17  0  +2.6  +2  +0.2  Miller, 1968  +4.0  -3.3  +0.2  V i r o , 1953  +0.4  Iwatsubo and Tsutsumi,1968  Coweeta, 1969/71 North annual C a r o l i n a average Oak Ridge Tennessee Maryland  1969/ 70  Beech f o r e s t a r e a near W e l l i n g t o n , New Z e a l a n d  -  +1.9  +4.6  -  Johnson and Swank, 1973.  Swank and Elwood, 1971 Calculated from d a t a i n C l e a v e s et al.3 1970.  +1  -8  Finland  -2.1  -3.6  Japan  +0.4  -10  -3.0  -10.0  -1.0  +3.8  +0.2 -  •  +4.9  -  Fredriksen, 1972.  186 s i g n i f i c a n t r e l a t i o n s h i p s between n e t l o s s e s and amount o f p r e c i p i t a t i o n f o r watersheds A and (B+C) which showed i n c r e a s e s i n n e t l o s s e s o f a l l c h e m i c a l s except n i t r o g e n as t h e amount o f p r e c i p i t a t i o n i n c r e a s e s The  most o u t s t a n d i n g  d i f f e r e n c e s between Haney and Seymour a r e t h e much  g r e a t e r c h l o r i d e l o s s e s a t Seymour.  These may be a f u n c t i o n o f t h e c l o s e r  p r o x i m i t y o f Seymour t o t h e sea c a u s i n g windblown s a l t a e r o s o l s  (Appendix X I V ) .  i t to  catch  greater quantities of  ( C l a y t o n , 1972; Juang and Johnson, 1967).  Effects of clearcutting I n t h e s i x month p e r i o d f o l l o w i n g c l e a r c u t t i n g , t h e r e has been a n e t l o s s of a l l chemicals, pected  except n i t r o g e n , from each o f t h e watersheds.  i n view o f the f a c t t h a t net l o s s e s i n the undisturbed  l y occurred during winter  and s p r i n g .  T h i s was ex-  watersheds u s u a l -  The n e t l o s s e s f o l l o w i n g c l e a r c u t t i n g  were g r e a t e r than i n t h e e n t i r e 1972/73 water y e a r .  T h i s can be a t t r i b u t e d t o  the heavy p r e c i p i t a t i o n f o l l o w i n g c l e a r c u t t i n g which, i n s i x months, has exceeded t h a t f o r t h e 1972/73 water By comparing c h e m i c a l  year.  budgets o f watershed A t o those o f t h e u n d i s t u r b e d  watershed C (Table 4.16), i t was found t h a t p o t a s s i u m l o s s e s were g r e a t l y i n creased  ( s i g n i f i c a n t a t P<0.01) and n i t r o g e n g a i n s d e c r e a s e d  (significant at  P<0.01, and due t o changes i n n i t r a t e b u t n o t ammonium budgets) f o l l o w i n g clearcutting  (Appendix X ) .  F o r watershed  (B+C), however, p o t a s s i u m , sodium,  magnesium and c h l o r i d e l o s s e s were s i g n i f i c a n t l y i n c r e a s e d  (P<0.01) and n i t r a t e ,  but n o t t o t a l n i t r o g e n , g a i n s were s i g n i f i c a n t l y d e c r e a s e d  (P<0.05) by c l e a r -  cutting  (Appendix X ) .  posing during  As t h e s l a s h i n watershed B had time t o s t a r t  decom-  l a t e summer and e a r l y autumn i n 1973, u n l i k e t h e s l a s h i n water-  shed A, and as s i t e exposure i n watershed B has been more p r o l o n g e d , d u r i n g a warm p e r i o d , p o s t - c l e a r c u t t i n g c h e m i c a l expected t o be g r e a t e r than t h o s e Phosphorus i n p u t s and o u t p u t s ed by c l e a r c u t t i n g .  especially  l o s s e s from watershed B were  from watershed A. were e x t r e m e l y low and have n o t been a f f e c t -  A t Hubbard Brook, f o r e s t c u t t i n g and h e r b i c i d e a p p l i c a t i o n  187 has i n c r e a s e d phosphorus very small  l o s s e s from a watershed, b u t t h e l o s s e s a r e s t i l l  (0.1 kg/ha/yr) and most o f t h e l o s s e s were i n p a r t i c u l a t e  (Hobbie and L i k e n s , 1973). N i t r o g e n has s t i l l  form  Such l o s s e s c o u l d n o t be d e t e c t e d a t Haney.  been accumulated i n each watershed f o l l o w i n g  clear-  c u t t i n g b u t t o a l e s s e r e x t e n t t h a n i n t h e u n d i s t u r b e d watershed C. A l t h o u g h i t i s t o o soon t o draw d e f i n i t e c o n c l u s i o n s , i t appears t h a t c l e a r c u t t i n g has s i g n i f i c a n t l y a f f e c t e d c e r t a i n c h e m i c a l budgets a t Haney, p r i m a r i l y due t o i n c r e a s e d amounts o f r u n o f f i n t h e c a s e o f sodium, magnesium and c h l o r i d e as t h e c o n c e n t r a t i o n s o f t h e s e c h e m i c a l s were n o t s i g n i f i c a n t l y a f f e c t e d by c l e a r c u t t i n g . Stream C h e m i s t r y - G e n e r a l D i s c u s s i o n 1.  U n d i s t u r b e d watersheds a.  Comparison w i t h Zeman's d a t a f o r t h e nearby Seymour watershed  The streams s t u d i e d a t Haney e x h i b i t g e n e r a l l y s i m i l a r c h e m i c a l b e haviour t o those s t u d i e d elsewhere.  A l t h o u g h i n s u f f i c i e n t d a t a were p r e -  s e n t e d by Zeman (1973) t o p e r m i t f u l l comparison o f t h e streams a t Haney w i t h Jamieson Creek i n t h e nearby Seymour watershed, i t seems t h a t chemical behaviour i s r a t h e r s i m i l a r . at  their  C h e m i c a l c o n c e n t r a t i o n s i n t h e streams  Haney a r e s l i g h t l y g r e a t e r t h a n t h o s e i n Jamieson Creek a l t h o u g h mag-  nesium and c h l o r i d e c o n c e n t r a t i o n s a t Haney a r e lower t h a n a t Seymour. The major mechanism c o n t r o l l i n g streamwater c h e m i s t r y i n s o u t h w e s t e r n B.C.,  and e l s e w h e r e i n t h e humid temperate r e g i o n s o f t h e w o r l d , i s m i n e r a l  weathering  (Gibbs, 1970; Gorham, 1961).  However, where w e a t h e r i n g s u p p l i e s  o n l y s m a l l amounts o f c h e m i c a l s t o streams, t h e n t h e c o n t r i b u t i o n o f p r e c i p i t a t i o n t o streamwater c h e m i s t r y can be The g e o l o g i c a l s u r v e y o f t h e a r e a  significant.  (Roddick, 1965) i n d i c a t e s t h a t t h e  b e d r o c k a t Haney and Seymour a r e q u i t e s i m i l a r , a l t h o u g h t h e Haney bedrock  188  contains r e l a t i v e l y more b i o t i t e and potash feldspar while the Seymour bedrock contains r e l a t i v e l y more quartz and hornblende.  These differences  i n composition, together with the f a c t that b i o t i t e weathers more r a p i d l y than hornblende,  suggest that mineral weathering w i l l release greater quan-  t i t i e s of chemicals at Haney than at Seymour. Rates of weathering may also be important.  A higher weathering r a t e  i n the low e l e v a t i o n watersheds a t Haney compared to that i n the higher elevation Seymour watershed may also help t o explain differences i n stream chemistry.  Differences i n p r e c i p i t a t i o n chemistry may also contribute t o  d i f f e r e n c e s i n stream  chemistry.  Higher chloride concentrations i n the stream at Seymour may r e f l e c t the closer proximity of Seymour to the sea with the p r e c i p i t a t i o n at Seymour being  r i c h e r i n chloride.  A comparison of p r e c i p i t a t i o n data sup-  ports t h i s conclusion. b.  Seasonal behaviour  Most of the chemical parameters measured exhibited prounounced seasonal v a r i a t i o n s with maximum values i n late summer t o early autumn and minimum values from winter t o early spring.  Major exceptions were n i t r a t e and dissolyed oxy-  gen concentrations which had maximum values i n winter and minimum values i n summer.  The seasonal pattern i n concentrations, however, suggests that the  stream chemistry was dominated by annual c y c l e s .  These involved b i d l o g i c a l and  geological breakdown i n the warmer part of the year with accumulation* of chemic a l s during dry periods, followed by the flushing of these chemicals i n t o streams by the autumn r a i n s .  This was followed by a period of r e l a t i v e b i o -  l o g i c a l and g e o l o g i c a l i n a c t i v i t y u n t i l temperatures spring.  rose again the following  During that time, there was l i t t l e addition to the supply of chemicals  available f o r movement i n t o streamwater.  At the same time, the lack of b i o l o g i -  cal  189 During  a c t i v i t y a l l o w e d movement o f n i t r o g e n compounds i n t o streamwater.  the warmer p a r t o f t h e y e a r , however, b i o l o g i c a l uptake a l l o w e d l i t t l e movement o f n i t r o g e n out o f the t e r r e s t r i a l c.  V a r i a t i o n with  D e c r e a s e s i n pH, bicarbonate  ecosystem,  discharge  and sodium, c a l c i u m , magnesium, d i s s o l v e d s i l i c a ,  c o n c e n t r a t i o n s were observed  ium c o n c e n t r a t i o n s tended a l t h o u g h t h e y tended  with increasing discharge.  t o g e n e r a l l y decrease  and  Potas-  with i n c r e a s i n g discharge  t o i n c r e a s e w i t h d i s c h a r g e d u r i n g storm e v e n t s .  Chem-  i c a l s which i n c r e a s e i n c o n c e n t r a t i o n w i t h i n c r e a s i n g d i s c h a r g e have been assumed t o o r i g i n a t e l a r g e l y from s u r f a c e r u n o f f o r p r e c i p i t a t i o n , u n l i k e t h o s e showing the o p p o s i t e b e h a v i o u r from seepage o f water through 1970).  which have been assumed t o o r i g i n a t e the s o i l  (e.g. Buscemi, 1969;  largely  W e i s e l and  Newell,  T h i s w i l l be d i s c u s s e d i n more d e t a i l i n the f o l l o w i n g c h a p t e r .  T a b l e 4.19  Streamwater c h e m i s t r y d u r i n g a 24-hour p e r i o d , 5-6  Parameter mean potassium sodium magnesium calcium chloride sulphate silica bicarbonate electrical conductivity discharge  Stream A max.  .31 1.32 .30 1.1 1.2 2.5 . 5.1 8.1 20.4 3.8  .32 1.32 .30 1.2 1.4 2.5 5.5 8.5 20.3 3.8  min.  mean  .29 1.30 .29 1.0 1.1 2.0 4.5 7.6  .18 1.14 .32 1.5 1.1 2.5 4.8 7.9  20.6 3.8  20.7 12.4  Stream B max. .20 1.15 .33 1.6 1.2 2.5 5.0 8.1 20.9 12.4  November,  min.  mean  .17 1.12 .32 1.3 1-1 2.5 4.5 7.6  .06 1.13 .31 2.0 1.0 2.5 5.3 9.4  20.5 12.4  Ten samples were c o l l e c t e d p e r stream w i t h a sampling 2-1/2 hours.  21.4 7.2  1973  Stream C max.  min.  .06 1.15 .32 2.1 1.0 2.5 5.5 9.7 21.6 7.2  .05 1.11 .31 2.0 .9 2.5 5.1 9.0 21.2 7.2  i n t e r v a l of  A l l c o n c e n t r a t i o n s are i n m g / l i t r e , c o n d u c t i v i t y i s i n micromho/cm a t 25°C, and d i s c h a r g e i s i n l i t r e s / s e c . I r o n , manganese, aluminium, ammonium, phosphate, and n i t r a t e c o n c e n t r a t i o n s were a l l c l o s e t o o r below t h e i r r e s p e c t i v e d e t e c t i o n l i m i t s .  190  With r e l a t i v e l y constant discharge, chemical concentrations i n the streams were quite constant throughout^ the day s l i g h t differences observed may  (Tables 4.19 and 4.20); the  be due more to a n a l y t i c a l error than to  r e a l d i f f e r e n c e s . Concentrations thus appeared to depend more on season and discharge than on time of day. Cleaves et al. 2.  Similar r e s u l t s have been reported by  (1970) for a small stream i n Maryland.  E f f e c t s of c l e a r c u t t i n g on stream chemistry a.  Results of t h i s study  Streams A and B have been studied f o r a period of only s i x months a f ter c l e a r c u t t i n g .  During t h i s period only potassium  s i g n i f i c a n t l y changed.  concentrations have been  S l i g h t changes i n other parameters have been noted  above. Neither of the two clearcut watersheds has yet been subjected to a long warm period when slash decomposition  and mineral weathering i s most a c t i v e .  At the end of March, 1974, the termination of data c o l l e c t i o n f o r t h i s thesis, the f o l i a g e on the s l a s h i n watershed A was  s t i l l green.  As discussed i n the  following chapter, maximum carbonic acid concentrations, and hence leaching potential,  of the s o i l water w i l l occur during the f i r s t autumns following  clearcutting.  Thus, maximum release of chemicals from the slash and s o i l s  should not yet have occurred but w i l l probably occur during the summers of 1974 and 1975.  The chemicals released should  have the greatest e f f e c t on  stream concentrations during the l a t e summer-early autumn periods of 1974 and 1975 i n view of the r e s u l t s of other studies and observations of streams D and E.  Dissolved oxygen concentrations are expected to decrease  signifi-  cantly during the coming summers with greater decreases i n stream A due mainly to i t s smaller s i z e . b.  Results of other studies  There have been r e l a t i v e l y few studies i n v e s t i g a t i n g the e f f e c t s of c l e a r cutting on streamwater chemistry and most of these have a number of  shortcomings.  191 T a b l e 4.20  Streamwater  Parameter potassium sodium magnesium calcium ammonium sulphate nitrate silica electrical conductivity discharge  c h e m i s t r y d u r i n g a 24 hour p e r i o d , 24-25 June, 1972.  Stream A max. mean .16 1.40 .38 1.9 . .01 .6 .26 6.9 22.5 1.1  .17 1.42 .39 1.9 .02 .7 .29 7.6 22.9 1.4  min.  Stream B max. mean  .16 1.39 ' .38 1.8 .01 .5 .22 6.6  .10 1.24 .39 2.1 .01 1.0 .21 5.4  22.1 1.1  22.7 5.9  .20 1.26 .40 2.1 .04 1.5 .27 5.6 23.0 9.0  min.  Stream C max. mean  .09 1.23 .39 2.1 <.01 1.0 .18 5.2  .07 1.22 .41 2.5 .01 1.0 .25 5.6  22.4 3.0  24.0 3.8  min. .07 1.20 .40 2.5 .01 1.0 .20 5.4  .07 1.23 .41 2.6 .02 1.5 .33 5.6 24.6 4.2  23.4 3.2  T h i r t e e n samples were c o l l e c t e d f o r each o f streams A and B w i t h a s a m p l i n g i n t e r v a l o f 2 hours and f o u r samples were c o l l e c t e d f o r stream C w i t h a sampling i n t e r v a l o f e i g h t hours. A l l c o n c e n t r a t i o n s a r e i n m g / l i t r e , c o n d u c t i v i t y i s i n micromho/cm a t 25°C, and d i s c h a r g e i s i n l i t r e s / s e c . I r o n , aluminium, and phosphate c o n c e n t r a t i o n s were a l l c l o s e t o o r below t h e i r r e s p e c t i v e d e t e c t i o n l i m i t s , and manganese, b i c a r b o n a t e , and c h l o r i d e a n a l y s e s were n o t p e r f o r m e d .  The f i r s t ,  and most comprehensive work, i n v e s t i g a t i n g t h e e f f e c t s o f  c l e a r c u t t i n g on stream c h e m i s t r y i s t h a t c a r r i e d o u t a t Hubbard Brook.  The  study o f t h e e f f e c t s o f complete v e g e t a t i o n removal on stream c h e m i s t r y ( L i k e n s et al., 1970) i n d i c a t e d what might happen t o streams f o l l o w i n g Recent p a p e r s from Hubbard Brook  clearcutting.  (Hornbeck et al., 1973; P i e r c e et al.', 1972)  have r e p o r t e d t h e e f f e c t s o f commercial c l e a r c u t t i n g on stream c h e m i s t r y .  The  f i r s t o f t h e s e ( P i e r c e et al., 1972) was r a t h e r l i m i t e d i n t h a t o n l y c a l c i u m , n i t r a t e , s u l p h a t e , and c o n d u c t i v i t y d a t a were p r e s e n t e d , u n l i k e t h e more comp r e h e n s i v e paper which f o l l o w e d  (Hornbeck et al., 1973).  In both cases, the  c h e m i s t r y o f a stream was s t u d i e d b e f o r e a s w e l l as a f t e r c l e a r c u t t i n g .  This  a v o i d s t h e n e c e s s i t y o f assuming t h a t c h e m i c a l c o n c e n t r a t i o n s i n a stream i n a c l e a r c u t watershed would have been t h e same as t h o s e i n a stream i n a nearby u n c u t watershed, had t h e f i r s t watershed n o t been c u t .  P i e r c e et al. (1972)  do use t h i s assumption, however, i n p a r t o f t h e i r p a p e r , and i t i s a l s o used  192 i n s e v e r a l o f the o t h e r p a p e r s . i n v a l i d , as d i s c u s s e d The  c a r r i e d out a t Coweeta by Johnson and  C a l c i u m , magnesium, sodium, and  which had was  potassium concentrations  o f which c o n t a i n e d  begun a l m o s t t h i r t y y e a r s  i s no p r e t r e a t m e n t d a t a  undisturbed  f o r e s t , and  and  a f t e r the  that:  p.  (1973).  Because  of  monitoring  s t a r t o f the v a r i o u s t r e a t m e n t s ,  the c o n c l u s i o n s  considered  Swank  the o t h e r t h r e e  are based on the assumption  there stated  "Comparison o f r e s u l t s among the  catchments i s p r i m a r i l y a c o n t r a s t i n management h i s t o r i e s . " 1973:  generally  were m o n i t o r e d i n f o u r  complex treatment h i s t o r i e s d a t i n g back t o 1942.  above so t h a t i t was  t o be  below.  second study was  watersheds, one  T h i s assumption i s c o n s i d e r e d  four  (Johnson and  Swank,  77).  T h i s statement i s f e l t t o be  i n c o r r e c t s i n c e the c h e m i s t r y  a t Coweeta i s l i k e l y t o be c o n t r o l l e d by bedrock and Gorham, 1961)  and  soil  o f the  chemistry  streams  (Gibbs,  even s l i g h t d i f f e r e n c e s i n g e o l o g y between the f o u r watersheds  c o u l d cause s i g n i f i c a n t d i f f e r e n c e s i n streamwater c a t i o n c o n c e n t r a t i o n s . i s noteworthy t h a t the s o i l s i n the f o u r watersheds are r e s i d u a l and from a heterogeneous bedrock which i s b a s i c a l l y g n e i s s but d i o r i t e , mica g n e i s s and mica s c h i s t . stream c h e m i s t r y The  and  5  D i f f e r e n c e s between streams 1 and  (Table 4.21)  are o b v i o u s .  the assumption t h a t one  S i m i l a r , but  t h i r d s t u d y was  i n c o a s t a l Oregon.  s i m i l a r watersheds i n  2 and  been found t o  between streams  be 3,  l e s s spectacular differences  T h i s f u r t h e r p o i n t s out the weakness o f  stream w i l l e x h i b i t i d e n t i c a l c h e m i c a l  t o a n o t h e r i f b o t h have s i m i l a r bedrock and  Basin  includes granite,  o v e r the same bedrock has  have been found f o r streams a t Haney.  The  derived  Under such c o n d i t i o n s d i f f e r e n c e s i n  o f streams f l o w i n g t h r o u g h a p p a r e n t l y  the C h i l l i w a c k v a l l e y a r e a o f B.C.  4,  It  between the watersheds would seem i n e v i t a b l e .  chemistry  quite d i f f e r e n t .  1970;  concentrations  f o r e s t cover.  c a r r i e d out by Brown et al.  (1973) i n the  Streams were sampled p r i o r t o l o g g i n g and  have q u i t e d i f f e r e n t n i t r a t e c o n c e n t r a t i o n s ,  with  Alsea found t o  the h i g h e s t n i t r a t e  concen-  193 T a b l e 4.21  C a t i o n c o n c e n t r a t i o n s i n s i m i l a r streams i n t h e C h i l l i w a c k v a l l e y area. November 1972.  Bedrock  Stream  K  Na  Mg mg/1  Ca  <  cond.  > ymho/cm a t 25°C  G r a n i t i c (Mainly granodiorite  1 2  .4 1.0  .6 1.1  .3 .9  1.3 3.8  16 39  V o l c a n i c s (Basic volcanics, tuff, and agglomerate)  3 4 5  .6 .2 .1  1.3 1.2 .6  1.2 1.9 1.3  12 13 10  79 124 93  Streams 1 and 2 a r e comparable i n s i z e , and were sampled w i t h i n 15 minutes of each o t h e r . They f l o w p a r a l l e l t o one another through u n d i s t u r b e d f o r e s t , down t h e same h i l l s i d e , a p p r o x i m a t e l y 2 km a p a r t , i n t o C h i l l i w a c k Lake. Both t h e i r watersheds l i e w i t h i n t h e same g e o l o g i c a l u n i t . Streams 3, 4, and They were sampled another, down t h e Creek. A l l t h r e e  5 a r e a l s o comparable i n s i z e b u t s m a l l e r than 1 and 2. w i t h i n 20 minutes o f each o t h e r and f l o w p a r a l l e l t o one same h i l l s i d e , a l l w i t h i n a d i s t a n c e o f 2 km, i n t o F o l e y watersheds l i e w i t h i n the same g e o l o g i c a l u n i t .  t r a t i o n s o c c u r r i n g i n t h e watersheds w i t h abundant  Alnus rubra.  Clearcutting  was f o l l o w e d by s l a s h b u r n i n g so t h e study cannot d i f f e r e n t i a t e between t h e e f f e c t s o f c l e a r c u t t i n g and t h o s e o f s l a s h b u r n i n g .  Data f o r o n l y t h r e e chemi-  c a l s - p o t a s s i u m , n i t r a t e , and phosphate - a r e r e p o r t e d .  Of t h e s e ,  c o n c e n t r a t i o n s i n c r e a s e d i n i t i a l l y b u t soon d e c l i n e d t o p r e t r e a t m e n t  potassium levels;  n i t r a t e c o n c e n t r a t i o n s were i n c r e a s e d s i g n i f i c a n t l y f o r t h e two y e a r s o f p o s t treatment  d a t a , and phosphate c o n c e n t r a t i o n s remained low and unchanged.  t h e same study, a stream f l o w i n g from another  watershed which was 25% c l e a r -  c u t i n t h r e e u n i t s , one o f which was s l a s h b u r n e d , changes i n c h e m i c a l The  t h i s study chemical Secondly,  showed no s i g n i f i c a n t  concentrations.  f o u r t h study was c a r r i e d o u t by F r e d r i k s e n  Experimental  In  F o r e s t , a l s o i n c o a s t a l Oregon.  is difficult  f o r two r e a s o n s .  (1971) i n t h e H.J. Andrews  I n t e r p r e t a t i o n o f the r e s u l t s o f  Firstly,  t h e r e a r e no  pretreatment  d a t a f o r t h e streams, g i v i n g r i s e t o t h e problems d i s c u s s e d above. c l e a r c u t t i n g extended o v e r a p e r i o d o f f o u r y e a r s and proceeded  s e q u e n t i a l l y from t h e r i d g e tops and t h e head o f t h e watershed down t o t h e  194 stream c h a n n e l s est to  (R.L. F r e d r i k s e n : p e r s o n a l communication).  which remained  The  s t r i