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UBC Theses and Dissertations

Influence of stocking and density upon growth and yield of trees and stands of Coastal western hemlock Osborn, John E. 1968

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INFLUENCE OF STOCKING AND DENSITY UPON GROWTH AND.Y I ELD OF TREES AND STANDS OF C0A5TAL WESTERN HEMLOCK by - J . E. OSBQRN B. S c . , U n i v e r s i t y o f W a l e s , 1962 M. F . , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1965 A THESIS. SUBMITTED IN PART IAL FULF ILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n t h e F n c u l t y o f FORESTRY Ws a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERS ITY OF BR IT I5H COLUMBIA S e p t e m b e r , 1968 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d S t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may b e g r a n t e d b y t h e H e a d o f my D e p a r t m e n t o r b y h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t b e a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f Fore.q-h-ry T h e U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8, C a n a d a D a t e September nOth. 1 Q 6 8 i i ABSTRACT , V a r i a t i o n s i n w e s t e r n h e m l o c k t r e e and s t a n d g r o w t h w s r e a n a l y s e d t o d e t e r m i n e t h e r e l a t i v e i m p o r t a n c e o f c a u s a t i v e f a c -t o r s . F o u r p h a s e s i n a s t a n d ' s l i f e - c y c l e we re i n v e s t i g a t e d ( s e e d l i n g e s t a b l i s h m e n t , j u v e n i l e g r o w t h , e a r l y s t a n d f o r m a t i o n , and m i d d l e - a g e ) . D e t a i l e d a n a l y s e s o f t r e e g r o w t h were made a t t h e t i m e o f e a r l y s t a n d f o r m a t i o n (25 t o 35 y e a r s ) . S t a n d g r o w t h and y i o l d d a t a ' ( 1 5 t o 160 y e a r s ) we re a n a l y s e d by m u l t i p l e r e -g r e s s i o n me thods t o a s c e r t a i n t h e e f f e c t s o f v a r y i n g d e n s i t y r e g i m e s on t i m e and m a g n i t u d e o f maximum wood vo l ume p e r a c r e . In a l l s t a n d s s t u d i e d , t r e e h e i g h t was u n a f f e c t e d by v a r i a -t i o n s i n s t a n d d e n s i t y . D e t a i l e d a n a l y s e s o f c u r r e n t b r o a s t -h n i g h t r a d i a l g r o w t h i n d i c a t e d t h a t t h e f a c t o r s o f a n t e c e d e n t g r o w t h , t r e e d . b . h . , s t a n d d e n s i t y , a g o , and s i t e q u a l i t y w e r e o f d e c r e a s i n g i m p o r t a n c e i n t h e o r d e r l i s t e d . S t a t i s t i c a l l y , t h e b e s t m e a s u r e s o f s t a n d d e n s i t y we re r a t i o s o f c r o w n w i d t h and l i v e c r o w n l e n g t h w i t h t o t a l t r e e h e i g h t , a l t h o u g h s t a n d b a s a l a r e a p e r a c r e was o n l y s l i g h t l y l e s s s i g n i f i c a n t . S t a n d f e r t i l i s a t i o n w i t h n i t r o g e n s t i m u l a t e d t r e e r a d i a l g r o w t h and c h a n g e d t h e r e l a t i v e c o n c e n t r a t i o n s o f f o l i a r n u t r i -e n t s w i t h i n t h e c r o w n . L i m i t e d (15 t r e e s ) b i o m a s s s t u d i e s i n d i c a t e d t h a t p r o d u c t i o n p e r u n i t a r e a o f a b o v e - g r o u n d t r e e w e i g h t ( o v e n - d r y ) i n c r e a s e d l i n e a r l y w i t h g r e a t e r s t a n d d e n s i t y . i Y i e l d i n c r e a s e d d i r e c t l y i n p r o p o r t i o n t o t h e f r a c t i o n o f a r e a o c c u p i e d by t r e e s ( s t o c k i n g ) and c u r v i i i n e a r l y w i t h d e g r e e o f c r o w d i n g ( s t a n d d e n s i t y ) w i t h i n t h e a r e a o c c u p i e d . Mean i i i a n n u a l net volume i n c r e m e n t d i d not c u l m i n a t e even at s t a n d d e n s i t i e s of 500 s q u a r e f e e t of b a s a l n r e a per a c r e . Both i n t e n s i v e and e x t e n s i v e f o r e s t management was d i s -c u s s e d . W i t h i n t h e C o a s t a l hemlock zone t h e r e c o u l d ba many advantages f o r a s h e l t c r w o o d r e g e n e r a t i o n sys tem and t w o - s t o r e y h i g h f o r e s t w i t h w e s t e r n hemlock as a s u p p l e m e n t a r y s p e c i o s . INDEX OF CONTENTS TITLE PA§£ 1 i ABSTBAET i i INDEX OF CONTENTS i v INDEX Of TABLES v i i i INDEX G F F I G U R E S x i v 1 . OBJECTIVES, SOURCES OF DATA, AND METHODS OF ANALYSIS 1 A. Introduction .....1 B. The; problem 3 C. Sources of d$ta - ...,.10 i ) Establishment .....11 i i ) Growth of j u v e n i l e trees .....11 i i i ) E a rly stand formation .....13 i v ) Growth of trees i n young stands .....14 v) Growth of trees i n middle-aged stands .....15 v i ) Growth of western hemlock stands .....17 v i i ) Estimation of m o r t a l i t y 17 D. Methods of a n a l y s i s .....17 i ) D e s c r i p t i v e .....17 i i ) Measurements taken 18 a) External p h y s i c a l measurements .....IB b) I n t e r n a l p h y s i c a l measurements 22 c) F o l i a r analyses 24 i i i ) S t a t i s t i c a l techniques .....27 E. A p p l i c a b i l i t y of the r e s u l t s .....27 F. Chapter §jmmary .....28 V 2 . CHARACTER IST ICS OF COASTAL WESTERN HEMLOCK . . . . 30 A . D e s c r i p t i o n o f t h e s p e c i e s . . . . 30 i ) D i s t r i b u t i o n and r a n g e o f c o a s t a l w e s t e r n h e m l o c k . . . . 30 i i ) E c o l o g i c a l and s i l v i c a l c h a r a c t e r i s t i c s . . . . 31 i i i ) P a t h o l o g y . . . . 35 i v ) M e c h a n i c a l , p h y s i c a l , and c h e m i c a l p r o p e r -t i e s o f t h e s p e c i e s . . . . 40 v ) U t i l i s a t i o n . . . . 43 B. G r o w t h and management t e c h n i q u e s t o d a t e . . . . 45 i ) N o r t h A m e r i c a - . . . . 45 i i ) G r e a t B r i t a i n and E u r o p e . . . . 51 C . O p p o r t u n i t i e s f o r i m p r o v e m e n t o f management o f t h e s p e c i e s . . . . 54 D. C h a p t e r summary . . . . 56 3 . ESTABLISHMENT OF WESTERN HEMLOCK STANDS . . . . 58 A , N a t u r a l r e g e n e r a t i o n . . . . 58 i ) S eed o r i g i n , d e v e l o p m e n t and d i s s e m i n a t i o n . . . . 59 i i ) S e e d g e r m i n a t i o n and s e e d l i n g e s t a b l i s h m e n t . . . . 59 B, S e e d i n g and p l a n t i n g . . . . 92 i ) C h o i c e o f s i t e s . . . . 92 i i ) S e e d i n g t e c h n i q u e s . . . . 93 i i i ) P l a n t i n g t e c h n i q u e s . . . . 95 i v ) P l a n t a t i o n e s t a b l i s h m e n t . . . . 98 C , C h a p t e r summary . . . . 105 4 . GROWTH DF JUVEN I LE WESTERN HEMLOCK TREES (Ages 1 t o 10 ) . . . . 107 A . G r o w t h i n h e i g h t . . . . 107 B. G r o w t h i n b r e a s t - h e i g h t d i a m e t e r . . . » 122 C , G r o w t h i n c r o w n w i d t h . . . . 127 D, I n t e r a c t i o n b e t w e e n s i t e f a c t o r s . . . . 134 v i i ) E f f e c t s o f c o m p e t i t i o n and d i f f i c u l t i e s o f m e a s u r e m e n t i i ) E f f e c t s o f s i t e upon t r e e s i z e and g r o w t h , and s i g n i f i c a n c e o f c r o w n d e n s i t y and f o l i a r c o n t e n t i i i ) S i t e i n d e x and f o l i a r e l e m e n t c o n c e n t r a -t i o n E» C h a p t e r summary 5 . EARLY STAND FORMATION (Ages 11 t o 40 ) A , F a c t o r s a f f e c t i n g r a d i a l and b a s a l a r e a g r o w t h i ) A n t e c e d e n t g r o w t h and c u r r e n t g r o w t h i i ) C u r r e n t a b s o l u t e t r e e s i z e and i n d i v i d u a l t r e e g r o w t h i i i ) M e a s u r e s o f c o m p e t i t i o n and t r e e g r o w t h i v ) T r e e g r o w t h v a r i a t i o n s w i t h s i t e and age v ) Opt imum c o m b i n a t i o n s o f f a c t o r s and r e -l a t i o n s h i p s w i t h t r e e g r o w t h B, I n t e r a c t i o n o f s i t e f a c t o r s C , C h a p t e r summary 6 . GROWTH OF TREES IN YOUNG STANDS (Ages 25 t o 35) A , E f f e c t s o f c o m p e t i t i o n b e t w e e n t r e e s B. E f f e c t s o f f e r t i l i s a t i o n i n y o u n g s t a n d s C . D e t a i l e d s t e m a n a l y s e s o f y o u n g t r e e s D, D i s t r i b u t i o n o f m a c r o n u t r i e n t e l e m e n t s i n t h e c r o w n s o f w e s t e r n h e m l o c k t r e e s E , B i o m a s s c o m p o n e n t s and p r o d u c t i o n o f y o u n g w e s t e r n h e m l o c k t r e e s F. C h a p t e r summary 7 . GROWTH OF TREES IN MIDDLE-AGED STAND5 (Ages 45 t o 1 6 0 ) A , F a c t o r s a f f e c t i n g r a d i a l and b a s a l a r e a g r o w t h i ) A n t e c e d e n t g r o w t h and c u r r e n t g r o w t h i i ) C u r r e n t a b s o l u t e t r e e s i z e and i n d i v i d u a l t r e e g r o w t h 134 139 143 145 1 4 7 1 4 7 152 152 155 160 163 167 171 174 174 213 226 234 246 264 269 270 270 271 v i a i i i ) M e a s u r e s o f c o m p e t i t i o n and t r e e g r o w t h . . . . 271 i v ) T r e e g r o w t h v a r i a t i o n s w i t h s i t e and age . . . . 276 v ) Opt imum c o m b i n a t i o n s o f f a c t o r s and r e -l a t i o n s h i p s w i t h t r e e g r o w t h . . . . 276 B. I n t e r a c t i o n o f s i t e f a c t o r s . . . . 27B C . C h a p t e r summary . . . . 281 8 . GROWTH OF WESTERN HEMLOCK STANDS (Ages 15 t o 1 5 0 ) . . . . . 282 A . G r o w t h t r e n d s i n b a s i c s t a n d p a r a m e t e r s . . . . 282 i ) S tems p e r a c r e . . . . 287 i i ) A v e r a g e b r e a s t - h e i g h t d i a m e t e r . . . . 287 i i i ) Top h e i g h t . . . . 289 i v ) V o l u m e . . . . 290 v ) B a s a l a r e a . . . . 293 B. R e l a t i v e i m p o r t a n c e o f s t a n d p a r a m e t e r s i n g r o w t h t r e n d s . . . . 294 i ) Y i e l d - V o l u m e . . . . 294 i i ) Y i e l d - B a s a l A r e a . . . . 295 i i i ) I n c r e m e n t - B a s a l A r e a . . . . 297 i v ) I n c r e m e n t - V o l u m e . . . . 301 C . M o r t a l i t y . . . . 304 D. C h a p t e r Sjmmary . . . . 310 9 . GRAPHICAL SYNTHESIS OF 5TAND DYNAMICS . . . . 311 C h a p t e r Summary . . . . 327 1 0 . MANAGEMENT IMPL ICAT IONS . . . . 328 1 1 . CONCLUSIONS AND SUMMARY . . . . 337 B IBL IOGRAPHY . . . . . 348 APPENDIX I . A . FOREST BOUNDARY AND "BURNING HISTORY . . . . . 389 APPENDIX I . B . LOCATION OF EXPERIMENTAL PLOTS . . . . 390 APPENDIX I I . S C I E N T I F I C NAMES OF PLANTS . . . . 391 APPENDIX I I I . ABBREVIATIONS USED IN T O T . . . . 393 APPENDIX I V . PHYT050C I0UQGICAL .ASSOCIATIONS AMD GROUND SURFACE COVER . . . . 395 v i i i INDEX OF TABLES 1 . C h a r a c t e r i s t i c s o f s i t e t y p e s f o r e s t a b l i s h m e n t s t u d y 12 2 . B a s i c s t a t i s t i c s o f a r e a s and s a m p l e t r e e s i n e s -t a b l i s h m e n t s t u d y . . . . . . 13 3 . S t r a t i f i c a t i o n o f U . B . C . R e s e a r c h F o r e s t and c l a s s e s s a m p l e d . 16 4 . C o d i n g o f v e g e t a t i o n and s u r f a c e c o v e r i n g u s e d i n e s t a b l i s h m e n t p l o t s . 71 5 . D i s t r i b u t i o n o f s u r f a c e c o v e r c o m p o n e n t s o f t h r e e s i t e t y p e s . 72 6 . C lump a r e a , s t e m s p e r a c r e , and s t a t i s t i c s o f t r e e h e i g h t s w i t h i n c l u m p s o f e s t a b l i s h m e n t s t u d y . 74 7 . Mean , s t a n d a r d d e v i a t i o n , max imum, m i n i m u m , and c o e f f i c i e n t o f v a r i a t i o n o f s e v e r a l p a r a m e t e r s i n t h e f o u r t e e n c l u m p s i n e s t a b l i s h m e n t s t u d y . 79 8 . 5 i m p l e c o r r e l a t i o n c o e f f i c i e n t m a t r i x b e t w e e n s e v e n p a r a m e t e r s i n t h e f o u r t e e n c l u m p s o f t h e e s t a b l i s h -ment s t u d y . 80 9 . S e l e c t e d r e g r e s s i o n e q u a t i o n s s h o w i n g e f f e c t s o f a g e , s t a n d d e n s i t y , and s i t e upon mean h e i g h t ( f e e t ) o f f o u r t e e n c l u m p s i n e s t a b l i s h m e n t s t u d y . 81 1 0 . S e l e c t e d r e g r e s s i o n e q u a t i o n s s h o w i n g e f f e c t s o f a g e , . mean h e i g h t , and h e i g h t s t a n d a r d d e v i a t i o n upon maximum h e i g h t ( f e e t ) o f f o u r t e e n c l u m p s i n t h e e s t a b l i s h m e n t s t u d y . 82 1 1 . A n a l y s e s o f v a r i a n c e and c o v a r i a n c e s h o w i n g t h e e f f e c t o f t r e a t m e n t ( c l u m p e d o r o p e n - g r o w n ) upon t r e e s i z e and g r o w t h . Means c o m p a r e d o f 14 c l u m p -grown and 12 o p e n - g r o w n t r e e s . 83 1 2 , R e g r e s s i o n e q u a t i o n s s h o w i n g i m p o r t a n c e o f t r e e s i z e , a g e , s i t e , and c r o w d i n g i n a c c o u n t i n g f o r v a r i a t i o n i n t r e e b r e a s t - h e i g h t d i a m e t e r , h e i g h t , and c r o w n w i d t h . 85 1 3 , S i m p l e c o r r e l a t i o n c o e f f i c i e n t s b e t w e e n r o o t - c o l l a r d i a m e t e r g r o w t h and number o f t r e e s o v e r l a p p e d and s t e m s p e r a c r e , 87 i x 1 4 . R e l a t i o n s h i p s among r o o t - c o l l a r d i a m e t e r g r o w t h and t r e e s i z e and c o m p e t i t i o n . •«••• 88 1 5 . R e l a t i o n s h i p s among c rown w i d t h g r o w t h and d i a m e t e r g r o w t h and c r o w d i n g . . . . . . 91 1 6 . E f f e c t s o f l i g h t and s e e d - b e d s u b s t r a t e on h e i g h t g r o w t h o f n a t u r a l w e s t e r n h e m l o c k s e e d l i n g s , . . . . . 103 1 7 . H e i g h t ( f e e t ) o f n i n e - y e a r - o l d w e s t e r n h e m l o c k s p o t - s e e d e d a t d i f f e r e n t s p a c i n g s . . . . . . 112 1 8 . E f f e c t o f p l a n t i n g , l o s s o f t o p - s o i l and g r o u n d c o m p a c t i o n ( P l a n t a t i o n 34) on mean h e i g h t g r o w t h o f w e s t e r n h e m l o c k . . . . . . 113 1 9 . Crown c l o s u r e p e r c e n t a g e o f w e s t e r n h e m l o c k s t a n d s by s p a c i n g a t age n i n e . . . . . . . 113 2 0 . R e l a t i o n s h i p s among c u r r e n t h e i g h t ( f e e t ) and t r e e s i z e and c o m p e t i t i o n o f n i n e - y e a r - o l d w e s t e r n h e m l o c k t r e e s , u . . . . . 116 2 1 . R e l a t i o n s h i p s b e t w e e n c u r r e n t and a n t e c e d e n t h e i g h t ( f e e t ) , and t h e e f f e c t s o f s p a c i n g . ••••• 117 2 2 . R e l a t i o n s h i p s b e t w e e n c u r r e n t and a n t e c e d e n t h e i g h t ( f e e t ) . . . . . . 117 2 3 . R e l a t i o n s h i p s among c u r r e n t h e i g h t ( f e e t ) , t r e e s i z e , a n t e c e d e n t h e i g h t , g r o w t h and s p a c i n g , . . . . . 119 2 4 . R e l a t i o n s h i p s among p a s t h e i g h t i n c r e m e n t ( f e e t ) , c u r r e n t s i z e , and e f f e c t s o f s p a c i n g and c o m p e t i -t i o n . . . . . . 119 2 5 . B a s i c s t a t i s t i c s o f two p o p u l a t i o n s o f young w e s t e r n h e m l o c k t r e e s . . . . . . 120 2 6 . R e l a t i o n s h i p s among t r e e h e i g h t ( f e e t ) and t r e e and s i t e f a c t o r s f o r two p o p u l a t i o n s o f y o u n g w e s t e r n h e m l o c k t r e e s . . . . . . 121 2 7 . B r e a s t - h e i g h t d i a m e t e r ( i n c h e s ) o f n i n e - y e a r - o l d w e s t e r n h e m l o c k s p o t - s e e d e d a t d i f f e r e n t s p a c i n g s . . . . . . 123 2 8 . R e g r e s s i o n e q u a t i o n s o f f a c t o r s a c c o u n t i n g f o r v a r i a t i o n i n b r e a s t - h e i g h t d i a m e t e r ( i n c h e s ) o f n i . n e - y e a r - o l d w e s t e r n h e m l o c k t r e e s . . . . . . 125 2 9 . R e l a t i o n s h i p s among h e i g h t , c r o w n w i d t h and t h e i r i n t e r a c t i o n s w i t h b r e a s t - h e i g h t d i a m e t e r ( i n c h e s ) o f c o m p l e t e l y o p e n - g r o w n n i n e - y e a r - o l d w e s t e r n h e m l o c k t r e e s . . . . . . 126 X 30. R e l a t i o n s h i p s among b r e a s t - h e i g h t d i a m e t e r ( i n c h e s ) and trt3e and s i t e f a c t o r s f o r two p o p u l a t i o n s o f y o u n g w e s t e r n h e m l o c k t r e e s . .... 126 31. C rown w i d t h ( f o o t ) o f n i n e - y e a r - o l d w e s t e r n h e m l o c k s p o t - s e e d e d a t d i f f e r e n t s p a c i n g s . •••• 128 32. E f f e c t s o f m o r t a l i t y and s p a c i n g upon c r o w n c l o s u r e . .... 128 33. R e l a t i o n s h i p s among c r o w n w i d t h ( f e e t ) and t r e e s i z e and s p a c i n g o f n i n e - y e a r - o l d w e s t e r n h e m l o c k t r e e s . .... 129 34. R e l a t i o n s h i p s among c r own w i d t h ( f e e t ) , t r e e s i z e , and c o m p e t i t i o n and s i t e i n young w e s t e r n h e m l o c k t r e e s . .... 130 35. B a s i c s t a t i s t i c s o f b r a n c h and b a r k t h i c k n e s s c h a r a c t e r s o f t h i r t y - t h r e e y o u n g w e s t e r n h e m l o c k t r e e s , and t h e c o r r e l a t i o n w i t h t r e e b r e a s t -h e i g h t d i a m e t e r and c r o w n w i d t h . .... 132 36. V a r i a b l e s a c c o u n t i n g f o r v a r i a t i o n i n l e n g t h ( f e e t ) o f t h e l o n g e s t b r a n c h o f young w e s t e r n h e m l o c k t r e e s . . . . 133 37. R e l a t i o n s h i p s b e t w e e n t r e e s i z e and b r a n c h g r e e n w e i g h t and b u t t d i a m e t e r o f y o u n g w e s t e r n h e m l o c k t r e e s . .... 134 38. P r e d i c t e d h e i g h t , b r e a s t - h e i g h t d i a m e t e r , and c r o w n w i d t h f o r s p e c i f i e d a g e s , s i t e i n d i c e s ( S I ) , t r e e c l a s s e s ( T C ) , and c o m p a r i s o n s w i t h s t a n d a r d N o r m a l Y i e l d T a b l e s ( Y T ) . .... 135 39* E f f e c t o f s p a c i n g upon h s i g h t / c r o w n w i d t h (H/CW) and c r o w n w i d t h / b r e a s t - h e i g h t d i a m e t e r (CW/D) r a t i o s o f n i n e - y e a r - o l d w e s t e r n h e m l o c k t r e e s . .... 137 40. G r o w i n g - s p a c e , g r o w i n g - s p a c e r e q u i r e m e n t s , and s t e m s p e r a c r e o f t r e e s i n s p a c i n g t r i a l o f w e s t e r n h e m l o c k . .... 138 41. Crown c o m p e t i t i o n f a c t o r o f t h r e e n i n e - y e a r - o l d -w e s t e r n h e m l o c k s t a n d s a t d i f f e r e n t s p a c i n g s . .... 139 42, E f f e c t s o f c r o w n d e n s i t y upon b r e a s t - h e i g h t d i a m e t e r o f y o u n g w e s t e r n h e m l o c k t r e e s . .... 140 43, B a s i c s t a t i s t i c s o f f o l i a r c o n t e n t o f y o u n g w e s t e r n h e m l o c k t r e e s , and t h e i r s i m p l e c o r r e l a t i o n s w i t h s i t e i n d e x . .... 141 x i 4 4 . C o r r e l a t i o n m a t r i x f o r f o l i a r c o n t e n t p e r c e n t o f n i t r o g e n , p o t a s s i u m , and p h o s p h o r u s , i n young w e s t e r n h e m l o c k t r e e s . . . . . 142 4 5 . F o l i a r c o n c e n t r a t i o n s ( p e r c e n t o f o v e n - d r y w e i g h t ) o f n i t r o g e n , p h o s p h o r u s , p o t a s s i u m , and c a l c i u m , o f w e s t e r n h e m l o c k t r e e s . . . . . 142 4 6 . R e g r e s s i o n e q u a t i o n s f o r p r e d i c t i o n o f s i t e i n d e x f r o m f o l i a r n u t r i e n t c o n c e n t r a t i o n s ( e x p r e s s e d as p e r c e n t o f o v e n - d r y w e i g h t ) . . . . . 144 4 7 . B a s i c s t a t i s t i c s o f 1947 s a m p l e f r o m y o u n g s t a n d s ( age 14 ) i n N o r t h V a n c o u v e r . . . . . 146 4 8 . B a s i c s t a t i s t i c s o f 1 9 4 7 s a m p l e . f r o m y o u n g s t a n d s ( age 28) i n N o r t h V a n c o u v e r . . . . . 149 4 9 . B a s i c s t a t i s t i c s o f 1965 s a m p l e f r o m y o u n g s t a n d s on t h e e a s t e r n s i d e o f U . B . C . R e s e a r c h F o r e s t . 150 5 0 . B a s i c s t a t i s t i c s o f 1966 s a m p l e f r o m y o u n g s t a n d s on t h e e a s t e r n s i d e o f U . B . C . R e s e a r c h F o r e s t . . . . . 151 5 1 . R e l a t i o n s h i p s b e t w e e n c u r r e n t 5 - y e a r g r o w t h and 5 - y e a r a n t e c e d e n t g r o w t h o f f o u r p o p u l a t i o n s o f young w e s t e r n h e m l o c k . . . . . 153 2 2 5 2 . C o e f f i c i e n t s o f d e t e r m i n a t i o n p e r c e n t ( r and R ) b e t w e e n a b s o l u t e t r e e s i z e and r a d i a l and b a s a l a r e a g r o w t h o f young w e s t e r n h e m l o c k t r e e s . . . . . 154 5 3 . R e l a t i o n s h i p s among s t a n d d e n s i t y , t r e e s i z e , and g r o w t h o f y o u n g w e s t e r n h e m l o c k t r e e s . . . . . 157 5 4 . R e l a t i o n s h i p s among t r e e s i z e , s t a n d d e n s i t y , and g r o w t h when a p p l y i n g a d j u s t m e n t s f o r i n c o m p l e t e c r o w n c l o s u r e . . . . . 161 5 5 . R e l a t i o n s h i p s among a g e , s i t e q u a l i t y , and g r o w t h o f y o u n g w e s t e r n h e m l o c k t r e e s . . . . . 162 5 6 . F a c t o r s a c c o u n t i n g f o r v a r i a t i o n i n 5-yen r r a d i a l and b a s a l a r e a g r o w t h o f t r e e s i n s t a n d s o f young w e s t e r n h e m l o c k . . . . . 165 5 7 . P r e d i c t e d v a l u e s o f h e i g h t ( f e e t ) , b r e a s t - h e i g h t d i a m e t e r ( i n c h e s ) , and c r o w n w i d t h ( f e e t ) f r o m m u l t i p l e r e g r e s s i o n e q u a t i o n s i n c o r p o r a t i n g a g e , s i t e i n d e x , and b a s a l a r e a p e r a c r e . . . . . 169 5 8 . G r o w t h and y i e l d o f p e r m a n e n t s a m p l e p l o t s i n s e c o n d - g r o w t h s t a n d s o f w e s t e r n h e m l o c k i n N o r t h -w e s t e r n W a s h i n g t o n . . . . . 179 x i i 5 9 . S t a n d and g r o w t h s t a t i s t i c s f r o m a t h i n n i n g e x p e r i -ment ( p r o j e c t 56-2 ) i n 2 5 - y e a r - o l d w e s t e r n h e m l o c k / w e s t e r n r e d c e d a r s t a n d s a t U . B . C . R e s e a r c h F o r e s t , . . . . . 1 9 0 6 0 . R e l a t i o n s h i p s among c u r r e n t s i z e , a n t e c e d e n t s i z e , b a r k t h i c k n e s s , and e f f e c t s o f b a s a l a r e a l e v e l i n i m m a t u r e (age 15 t o 35) s t a n d s o f w e s t e r n h e m l o c k . 192 6 1 . E f f e c t s o f s t a n d d e n s i t y upon b a s a l a r e a g r o w t h and b r e a s t - h e i g h t d i a m e t e r o f y o u n g w e s t e r n h e m l o c k s t a n d s o f S . I . 1 1 0 . 195 6 2 . R e l a t i o n s h i p s among t r e e s i z e and s t a n d d e n s i t y , and g r o w t h a t b r e a s t - h e i g h t o f t h i r t y - y e a r - o l d w e s t e r n h e m l o c k t r e e s . . . . . . 2 0 1 6 3 . P r e d i c t e d i n c r e m e n t r a t e s f o r t r e e s i n s t a n d s o f v a r i a b l e d e n s i t y . . . . . . 2 0 3 6 4 . R e l a t i v e i m p o r t a n c e o f f a c t o r s a f f e c t i n g t h e r a d i a l g r o w t h a t b r e a s t - h e i g h t ( f i v e - y e a r ) o f y o u n g w e s t e r n h e m l o c k t r e e s . 206 6 5 . P r e c i s i o n o f r e g r e s s i o n e q u a t i o n s a c c o u n t i n g f o r t h e v a r i a t i o n i n r a d i a l i n c r e m e n t o f young w e s t e r n h e m l o c k t r e e s a t f o u r h e i g h t s up t h e s t e m . . . . . . 2 1 0 6 6 . T r e e , s t a n d , t r e a t m e n t d e t a i l s and e f f e c t s upon f o l i a g e w e i g h t , n e e d l e l e n g t h , w i d t h , and a r e a o f t e n y o u n g w e s t e r n h e m l o c k t r e e s . . . . . . . 2 2 0 6 7 . S i m p l e c o r r e l a t i o n c o e f f i c i e n t s b e t w e e n n e e d l e w e i g h t , n e e d l e l e n g t h , and n e e d l e s u r f a c e a r e a w i t h b r a n c h l e n g t h i n c r e m e n t , u p p e r s t e m r a d i a l i n c r e m e n t , and b r e a s t - h e i g h t r a d i a l i n c r e m e n t . 222 6 8 . C l a s s i f i c a t i o n o f s a m p l e t r e e s i n a g e / h e i g h t and s t e m p r o f i l e r e l a t i o n s h i p s . . . . . . 2 2 7 6 9 . T r e e and s t a n d d e t a i l s o f s a m p l e s i n s t e m a n a l y s i s . . . . . . 2 3 3 7 0 . F o l i a r c o n t e n t o f w e s t e r n h e m l o c k t r e e s by s i t e i n d e x and l e a f a g e . . . . . . 2 3 7 7 1 . F o l i a r c o n t e n t o f one w e s t e r n h e m l o c k t r e e a c c o r d -i n g t o p e r c e n t a g e o f t o t a l h e i g h t . . . . . . 2 3 7 7 2 . E f f e c t s o f n e e d l e a g e , h e i g h t up s t e m , f e r t i l i s a -t i o n , and b a s a l a r e a p e r a c r e o f s t a n d upon f o l i a r c o n t e n t o f s i x ( n i t r o g e n , p h o s p h o r u s , p o t a s s i u m , c a l c i u m , m a g n e s i u m , and s u l p h u r ) e l e m e n t s i n w e s -t e r n h e m l o c k t r e e s on S i t e I n d e x 1 1 0 . 2^0 x i i i 7 3 . E f f e c t o f a g e , p e r c e n t a g e h e i g h t up s tem and s t a n d d e n s i t y upon f o l i a r c o n c e n t r a t i o n i n w e s t e r n h e m l o c k tress. . . . . . 2 4 1 7 4 . A n n u a l d r y m a t t e r p r o d u c t i o n o f s e v e r a l s p e c i e s g r o w i n g a t B e d g e b u r y ( G r e a t . B r i t a i n ) . 250 7 5 . P e r c e n t a g e c o n t r i b u t i o n o f t o t a l rown c o m p o n e n t s o f w e s t e r n h e m l o c k , w e s t e r n r e d c e d a r , and D o u g l a s f i r b a s e d upon o v e n - d r y w e i g h t . . . . . . 2 5 1 7 6 . R e l a t i o n s h i p b e t w e e n b r e a s t - h e i g h t d i a m e t e r and o v e n - d r y c r o w n w e i g h t ( l b s ) f o r D o m i n a n t and C o d o m i n a n t w e s t e r n h e m l o c k t r e e s . . . . . . 2 5 2 7 7 . C o m p a r i s o n b e t w e e n p r e d i c t e d g r e e n w e i g h t s o f b o l e s and c r o w n s o f h e m l o c k t r e e s . . . . , . 2 5 7 7 8 . E f f e c t s o f s t a n d d e n s i t y upon s t a n d componen t w e i g h t s u x n r e s s e d as p e r c e n t a g e s o f t o t a l w e i g h t . 263 7 9 . B a s i c s t a t i s t i c s o f t h e 1966 s a m p l e f r o m m i d d l e -aged s t a n d s on t h e w e s t e r n and c e n t r a l s e c t i o n s o f U . B . C . R e s e a r c h F o r e s t . . # . . . 2 6 9 8 0 . R e l a t i o n s h i p s b e t w e e n c u r r e n t 5 - y e a r g r o w t h and 5-yea r a n t e c e d e n t g r o w t h o f t r e e s i n m i d d l e - a g e d w e s t e r n h e m l o c k s t a n d s . , , . . , 2 7 1 2 2 8 1 . C o e f f i c i e n t s o f d e t e r m i n a t i o n p e r c e n t ( r and R ) b o t w e e n a b s o l u t e t r e e s i z e and r a d i a l and b a s a l a r e a g r o w t h o f m i d d l e - a g e d w e s t e r n ' h e m l o c k t r e e s . 272 8 2 . R e l a t i o n s h i p s b e t w e e n s t a n d d e n s i t y , t r e e s i z e , and g r o w t h o f r n i d d l e - a g o d w e s t e r n h e m l o c k t r e e s . 274 8 3 . F a c t o r s a c c o u n t i n g f o r v a r i a t i o n i n r a d i a l and b a s a l a r e a g r o w t h o f w e s t e r n h e m l o c k t r e e s f r o m m i d d l e - a g e d s t a n d s . . . . . . 2 7 7 8 4 . B a s i c s t a t i s t i c s o f s t a n d d a t a f r o m t h e U . S . F . S . . , , . , 2 8 5 8 5 . B a s i c s t a t i s t i c s o f s t a n d d a t a f r o m t h e B . C . F . S . . . . . . 2 8 6 8 6 . B a s i c s t a t i s t i c s o f s t a n d d a t a f r o m B . C . P r i v a t e C o . . , , . . 2 8 6 x i v INDEX OF' FIGURES 1. I n i t i a l sampling procedure i n biomass s t u d i e s . .... 20 2. Longest branch sampling procedure. .... 21 3. Measurements of stem sample i n biomass s t u d y . .... 23 4. F o l i a r a n a l y s i s sampling procedure. .... 25 5. Map of E s t a b l i s h m e n t samples 5.1 and 5.2, showing dominant v e g e t a t i o n and s u r f a c e c o v e r i n g . .... 68 6 . Map of E s t a b l i s h m e n t samples 2.4 and 2.5, showing dominant v e g e t a t i o n and s u r f a c e c o v e r i n g . .... 69 7. Map of E s t a b l i s h m e n t sample 4.1, showing dominant v e g e t a t i o n and s u r f a c e c o v e r i n g . .... 70 8 . S e c t i o n and p l a n of t r a n s e c t between open-grown (0-G) and sample (S) trees i n E s t a b l i s h m e n t p l o t s , (a) 3.1, and (b) 3.3. .... 75 9 . S e c t i o n and p l a n o f t r a n s e c t between open-grown (0-G) and sample (S) t r e e s i n E s t a b l i s h m e n t p l o t s , (a) 3.2, and (b) 5.1/5.2. .... 76 10. R e l a t i o n s h i p s among clump h e i g h t s t a n d a r d d e v i a -t i o n ( a , c, e) and h e i g h t c o e f f i c i e n t s of v a r i a t i o n (b, d, f ) w i t h clump mean h e i g h t , stems per a c r e , and maximum r o o t - c o l l a r age. .... 77 11. R e l a t i o n s h i p s between t r e e s i z e and r o o t - c o l l a r r a d i a l growth f o r , (a) c u r r e n t y e a r , and '(b) past two and f i v e y e a r s , shuwing e f f e c t of o v e r l a p p i n g of crowns. . . . . 8 9 12. Optimum sampling scheme f o r a s s e s s i n g e f f e c t s of s i t e and c o m p e t i t i o n upon t r e e s i z e . .... 108 13. Height of l a r g e s t 10% western hemlock by age and s p a c i n g . .... 114 14. Mean height of a l l s p a c i n g s of 10% l a r g e s t of western hemlock ( P l a n t a t i o n 21), western red cedar, Douglas f i r , and 3 s p a c i n g of western hemlock ( P l a n t a t i o n 34). .... 115 15. E f f e c t s of s p a c i n g upon he i g h t and b r e a s t - h e i g h t diameter of n i n e - y e a r - o l d western hemlock t r e e s . .... 124 XV 1 6 , E f f e c t s o f s p a c i n g upon h e i g h t and c r o w n w i d t h o f n i n e - y e a r - o l d w e s t e r n h e m l o c k t r e e s . . . . . 124 1 7 . T h e o r e t i c a l c l o s i n g o f c r o w n s f r o m a c t u a l c o n d i t i o n (a) t o h y p o t h e t i c a l 100 p e r c e n t c r o w n c l o s u r e ( b ) . . . . . 159 I B . E f f e c t s o f ' a g o , s i t e c l a s s , s t o c k i n g and s t a n d d e n s i t y on y i u l d o f t r e e s (a ) and s t a n d s ( b ) . . . . . 176 1 9 . R e l a t i o n s h i p among g r o w t h p u t e n t i a l , a g e , and p a s t g r o w t h . . , . . 1B2 2 0 . R e l a t i o n s h i p o f s temwood p r o d u c t i o n p e r u n i t w e i g h t o f l e a v e s t o l o a f a r e a p e r t r e e i n t h r e e s t a n d s o f C h a m a e c y p a r i s o b t u s a . B a s a l a r e a p e r a c r e i n c r e a s e s f r o m s t a n d 1 t o s t a n d 3 ( a f t e r S a t a o and S e n d a , 1 9 5 8 ) . . . . . 182 2 1 . R e l a t i o n s h i p b e t w e e n c u r r e n t t r e e d . b . h . ( i . b . ) and t r e e d . b . h . ( i . b . ) f i v e y e a r s a g o . . . . . 193 2 2 . R e l a t i o n s h i p b e t w e e n 5-yea r d i a m e t e r i n c r e m e n t ( i n c h e s ) and s t a n d b a s a l a r e a . p e r a c r e ( s q u a r e f e e t ) . •«»• 194 2 3 . E f f e c t o f s t a n d d e n s i t y on b a s a l a r e a g r o w t h o f young w e s t e r n h e m l o c k s t a n d s o f S . I . 1 1 0 . . . . . 196 2 4 . E f f e c t o f s t a n d d e n s i t y upon b r e a s t - h e i g h t d i a m e t e r g r o w t h o f young w e s t e r n h e m l o c k s t a n d s o f S . I . 1 1 0 . . . . . 197 2 5 . E f f e c t o f s t a n d d e n s i t y upon b a s a l a r e a g r o w t h o f young w e s t e r n h e m l o c k s t a n d s , i n c l u d i n g i n g r o w t h , c f S . I . 1 1 0 . . . . . 199 2 6 . R e l a t i o n s h i p among f i v e - y e a r d i a m e t e r i n c r e m e n t , b r e a s t - h e i g h t d i a m e t e r ( i . b . ) , and t o t a l b a s a l a r e a p e r a c r e ( m u l t i p l e r e g r e s s i o n e q u a t i o n s ) . . . . . 202 2 7 . R e l a t i o n s h i p among f i v e - y e a r d i a m e t e r i n c r e m e n t , b r e ; : : s t - h e i g h t d i a m e t e r ( i . b , ) and t o t a l s t a n d b a s a l a r e a p e r a c r e ( s e p a r a t e s i m p l e l i n e a r e q u a t i o n s ) . <<•• 20 2 2 8 . R e l a t i o n s h i p s o f t r e e s i z e (h and d ) , and d i s t a n c e t o n e i g h b o u r s (D) i n (a) p r o f i l e , and (b) p l a n . «•«• 208 2 9 . E f f e c t s o f f e r t i l i s a t i o n a n , (a ) n e e d l e g r e e n w e i g h t , (b) n e e d l e s u r f a c e a r e a , ( c ) n o o d l e l e n g t h , and (d) n e e d l e w i d t h , by age o f s a m p l e . . . . . 218 3 0 . E f f e c t s o f f e r t i l i s a t i o n on a n n u a l r a d i a l i n c r e m e n t c u r r e n t ( 1 9 6 6 ) , a n t e c e d e n t ( 1 9 6 5 ) , and two y e a r s p r e v i o u s ( 1964 ) a t , (a ) s tump h e i g h t , (b) h a l f w a y t o b a s e o f l i v e c r o w n , ( c ) b a s e o f l i v e c r o w n , and (d) h a l f w a y t o t o p o f t r e e f r o m b a s e o f l i v e c r o w n . . . . . 224 E f f e c t o f b a s a l a r e a p e r a c r e upon a g e - h e i g h t r e l a t i o n s h i p s f r o m s t em a n a l y s e s . Stem p r o f i l e c h a r t o f w e s t e r n h e m l o c k t r e e s a t age 30 s h o w i n g e f f e c t s o f s i z e c l a s s and s t a n d d e n s i t y . S t e m ' p r o f i l o s , c r o w n s h a p e s , (a ) and ( c ) , and s t e m and c r o w n r a d i a l i n c r e m e n t , (b) and ( d ) , o f T r e e s Number 1 and 3 s h o w i n g e f f e c t s c f f e r t i l i s a t i o n and s t a n d d e n s i t y . Stem p r o f i l e s , c r o w n s h a p e s , (a ) and ( c ) , and s t e m and c r o w n r a d i a l i n c r e m e n t , (b) and ( d ) , o f T r e e s Number 7 and 10 s h o w i n g e f f e c t s o f f e r t i l i s a t i o n and s t a n d d e n s i t y . S p e c i f i e d l o c a t i o n s u s e d i n c o n s t r u c t i o n o f r e s u l t s o f F i g u r e 3 6 . To show e f f e c t s o f n e e d l e age and h e i g h t i n c rown on f o l i a r n u t r i e n t c o n c e n t r a t i o n s . E f f e c t s o f n e e d l e age and h e i g h t i n c r o w n on f o l i a r c o n t e n t o f , (a ) n i t r o g e n and s u l p h u r , (b) p h o s p h o r u s and p o t a s s i u m , ( c ) c a l c i u m and m a g n e s i u m , o f w e s t e r n h e m l o c k t r e e s i n a h y p o t h e t i c a l u n f e r t i l i s e d s t a n d o f 250 s q u a r e f e e t p e r a c r e on 5 . 1 . 1 1 0 , w i t h (d ) c o d i n g o f c o n c e n t r a t i o n s ( p e r c e n t o v e n - d r y w e i g h t ) . C o m p a r i s o n o f g r e e n b o l e w e i g h t (wood or b a r k ) r e -l a t i o n s h i p s w i t h t r e e h e i g h t ( a ) , t r e e b r e a s t - h e i g h t d i a m e t e r (b ) and l o g a r i t h m i c h e i g h t and b r e a s t -h e i g h t d i a m e t e r ( c ) , b e t w e e n t r e e s f r o m T e r r a c e and H a n e y , B . C . C o m p a r i s o n o f g r e e n c r o w n w e i g h t r e l a t i o n s h i p s w i t h l i v e c r o w n l e n g t h ( a ) , l o g . g ( b r e a s t - h e i g h t d i a m e t e r x l i v e c r o w n l e n g t h ) ( b ) , b r e a s t - h e i g h t d i a m e t e r ( c ) , and l i v e c r o w n l e n g t h ( d ) , b e t w e e n t r e e s f r o m •Terrace and H a n e y , B . C . E f f e c t s o f b a s a l a r e a p e r a c r e ( s q u a r e f e e t ) u p o n , (a ) o v e n - d r y w e i g h t o f t o t a l ( above g r o u n d ) , b o l e w o o d , b o l e b a r k , c r o w n , b r a n c h e s , and f o l i a g e , and (b ) s t a n d c o m p o n e n t s e x p r e s s e d as a p e r c e n t a g e o f t o t a l w e i g h t . R e l a t i o n s h i p s a m o n g y i e l d , p e r i o d i c a n n u a l g r o w t h and mean a n n u a l g r o w t h . R e l a t i o n s h i p s b e t w e e n s t e m s p e r a c r e and (a ) s t a n d a g e , (b) s t a n d d e n s i t y x v i i 42, R e l a t i o n s h i p s between stand average d.b.h. and, (a) stand ago, (b) stand d e n s i t y . .... 288 43, R e l a t i o n s h i p s between top height (feet) and, (a) stand ago, (b) stand d e n s i t y . .... 291 44, R e l a t i o n s h i p s between stand volume (cubic f e s t ) and, (a) stand age, (b) stand d e n s i t y . .... 291 45, R e l a t i o n s h i p among volume per acre, stand density and hoight. .,..292 46, Re l a t i o n s h i p ; between basal area per acre and stand age. ,...292 47, R e l a t i o n s h i p s among volume per acre, stand density, and age, .... 296 48, R e l a t i o n s h i p s among stand ago, basal area and mean net basal area increment. .... 299 49, Relationship-::; between mean net basal area per acre . increment and age. .... 300 50, R e l a t i o n s h i p s among merchantable volume moon annual increment, stand d e n s i t y and age c l a s s , .... 303 •51. R e l a t i o n s h i p s between ago and l i v i n g and dead basal area per acre. .... 307 52. R e l a t i o n s h i p s among b a s a l area per acre and m o r t a l i -ty (stems per a c r e ) , and e f f e c t s of stand age. .... 307 53. Diagrammatic r e p r e s e n t a t i o n of stand s i t e curves ( a f t e r Lewis, 1959). .... 313 54. H y p o t h e t i c a l t h i n n i n g regime i n a r e g u l a r l y - s p a c e d p l a n t a t i o n ensuring minimum stand donsity, maximum tree growth, and st o c k i n g to 100 per cent. * .... 317 55. R e l a t i o n s h i p s between stand y i e l d and stand density .... 319 56. R e l a t i o n s h i p s between tr e e s i z e ( y i e l d ) and stand d e n s i t y . ,...319 57. E f f e c t of s i t e q u a l i t y upon y i e l d and stand density r e l a t i o n s h i p s . .... 320 58. R e l a t i o n s h i p s between stand absolute growth rate and stand d e n s i t y . .... 320 59. R e l a t i o n s h i p s between r e l a t i v e growth rate of stands and i n d i v i d u a l trees with stand d e n s i t y . ' .... ^ 21 x v i i i 60. R e l a t i o n s h i p s b e t w e e n c r o w n w i d t h a b s o l u t e g r o w t h r a t e o f t r e e s o f d i f f e r e n t ages and s t a n d d e n s i t y . . . . 321 61. R e l a t i o n s h i p s b e t w e e n v o l u m e p e r a c r e mean n e t a n n u a l i n c r e m e n t a n d , (a ) s t a n d a g e , and (b ) s t a n d d e n s i t y . . . . . 325 6 2 . R e l a t i o n s h i p s among s t a n d v o l u m e , a g e , and b a s a l a r e a . ' . . . . 3 2 6 6 3 . R e l a t i o n s h i p s b e t w e e n n e t a b s o l u t e mean b a s a l a r e a i n c r e m e n t and b a s a l a r e a . . . . . 326 x i x ACKNOWLEDGEMENTS Tho w r i t e r w i s h e s t o a c k n o w l e d g e t h e c o n s t r u c t i v e c r i t i -c i s m and e n t h u s i a s t i c s u p p o r t g i v e n t o h im t h r o u g h o u t this s t u d y by h i s s u p e r v i s o r , D r . J . H . G . S m i t h . The t h e s i s was r e v i e w e d by D r s . P . G . Haddock ( F o r e s t r y ) , D. H a l e y ( F o r e s t r y ) , L . E . Lowe ( A g r i c u l t u r e - D e p t . o f S o i l S c i e n c e ) , D . D . Munro ( F o r e s t r y ) , J . H . G . S m i t h ( F o r e s t r y ) , and D . J . Wor t ( S c i e n c e - U e p t . o f B o t a n y ) . F o r t h e i r c r i t i c a l r e v i e w s and a d v i c e t h e w r i t e r i s g r a t e f u l . S e v e r a l F o r e s t r y F a c u l t y and S t a f f members a l s o c o n t r i b u t e d t o w a r d s t h i s t h e s i s and s p e c i a l t h a n k s a r e due t o D r . A . K o z o k f o r s t a t i s t i c a l a d v i c e , t o M r s . H. B e n m o r e , M r s . H . F r o e s e , and M r s , C. L i n d s a y f o r a s s i s t a n c e i n c o m p u t i n g , and t o M r s . M. Lambdon f o r a l l t h e d r a f t i n g work i n v o l v e d . G r o w t h and y i e l d d a t a were k i n d l y s u p p l i e d by s e v e r a l a g e n c i e s i n c l u d i n g t h e B r i t i s h C o l u m b i a F o r e s t S e r v i c e , t h e U n i t e d S t a t e s F o r e s t S e r v i c e , . t h e F o r e s t r y C o m m i s s i o n c f G r e a t B r i t a i n and p r i v a t e a g e n c i e s i n V a n c o u v e r . D r . G . S . A l l e n , R e s e a r c h O f f i c e r , D e p a r t m e n t o f F o r e s t r y and R u r a l D e v e l o p m e n t , V i c t o r i a , B . C . , s u p p l i e d t h e i n f o r m a t i o n on y o u n g s t a n d s f r o m N o r t h V a n c o u v e r . P e r m i s s i o n t o u se a l l t h e s e d a t a i s g r a t e f u l l y a c k n o w l e d g e d . A l l c h e m i c a l a n a l y s e s o f f o l i a r s a m p l e s wore c o n d u c t e d by C o m i n c o L t d . u n d e r t h e s u p e r v i s i o n o f D r . J . D . B e a t o n and M r . R . C , S p e c r . F i n a n c i a l s u p p o r t was g i v e n by t h e 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 C o l u m b i a , i n t h e f o r m o f T e a c h i n g and R e s e a r c h A s s i s t a n t s h i p s . The w r i t e r r e c e i v e d a N a t i o n a l R e s e a r c h X X C o u n c i l Studentship f o r both the 1966-67 and 1967-66 Sessions. Research conducted during the summer-of 1966 was financed by grants from Cominco Ltd. Above a l l , the w r i t e r wishes to acknowledge the a s s i s t a n c and encouragement he has r e c e i v e d from his f a m i l y and wife C h r i s t i n e , 1 . OB J ECT IVES . SOURCES OF DATA. AND METHODS OF ANALY5 I5 A . I n t r o d u c t i o n W e s t e r n h e m l o c k ( T s u q a h e t e r o p h y l l a ( R a f . ) S a r g . ) ^ " i s one o f f o u r N o r t h A m e r i c a n s p e c i e s o f t h e genus T s u q a . and i s t h e most i m p o r t a n t t i m b e r - p r o d u c e r . W i t h i n B r i t i s h C o l u m b i a t h e r e a r e 3 8 . 5 b i l l i o n c u b i c f e e t ( p r o d u c t i v e , a c c e s s i b l e , a l l a g e s , 12 i n c h e s and l a r g e r d . b . h . ) ( B r i t i s h C o l u m b i a F o r e s t 5 e r v i c e , I960), and 59 p e r c e n t o f t h i s i s i n t h e c o a s t a l r e g i o n . V o l u m e 3 o f t h e s p e c i e s i s s e c o n d o n l y t o t h e s p r u c e g r o u p i n B r i t i s h C o l u m b i a , and r a n k s s e c o n d t o D o u g l a s f i r i n p o t e n t i a l g r o w t h as d e f i n e d by t h e B r i t i s h C o l u m b i a F o r e s t S e r v i c e ( 1 9 5 7 ) . S i m i l a r s t a t i s t i c s f o r t h e U n i t e d S t a t e s a r e a s i n t h e P a c i f i c N o r t h w e s t we re g i v e n by M a l m b e r g ( 1 9 6 5 ) . F o r e s t r e g i o n s o f C a n a d a were c l a s s i f i e d by Rowe ( 1 9 5 9 ) on t h e b a s i s o f c l i m a t i c c l i m a x e s . W e s t e r n h e m l o c k i s t h e d o m i n a n t s p e c i e s i n t h r e e ( C . 2 , C . 3 , and C . 4 ) o f t h e f o u r s e c t i o n s i n t h e C o a s t a l r e g i o n , and a b u n d a n t i n t h e f o u r t h ( C l ) . The b e s t c l i -m a t i c c o n d i t i o n s f o r t r e e g r o w t h i n Canada a r e f o u n d i n t h e C o a s t a l r e g i o n . B e r n s t e n ( 1958 ) and M a l m b e r g ( 1 9 6 5 ) s t a t e d t h a t t h e b e s t g r o w t h p e r f o r m a n c e s o f t h i s s p e c i e s a r e on t h e m o i s t s i t e s a l o n g t h e c o a s t . L and use f o r f o r e s t r y i s c o n s i d e r e d e x c e l -l e n t f o r t h e C o a s t a l w e s t e r n h e m l o c k z o n e a c c o r d i n g t o K r a j i n a " ' " S c i e n t i f i c names o f a l l s p e c i e s c i t e d i n t h e t e x t a r e g i v e n i n A p p e n d i x I I . 2 D i a m e t e r a t b r e a s t - h e i g h t . A l i s t o f a b b r e v i a t i o n s and a g l o s s a r y o f t e r m s u s e d i s g i v e n i n A p p e n d i x I I I . 3 See B r i t i s h C o l u m b i a F o r e s t S e r v i c e ( 1 9 5 7 ) , i n c l u d i n g : b l a c k , E n g e l m a n n , S i t k a , and w h i t e s p r u c e . 2 ( 1 9 6 5 ) . E m p i r i c a l y i e l d t a b l e s f o r n a t u r a l s t a n d s i n B r i t i s h C o l u m b i a show t h a t y i e l d s i n t h e c o a s t f o r e s t r e g i o n may be two t o t h r e e t i m e s t h e a v e r a g e y i e l d o f good s i t e s o v e r much o f t h e i n t e r i o r ( F l i g g , I 9 6 0 ) . C o a s t a l w e s t e r n h e m l o c k ^ , w i t h i t s l a r g e a c c e s s i b l e v o l u m e , h i g h g r o w t h p o t e n t i a l , and r e l a t i v e l y h i g h p r o d u c t v a l u e s , i s a d m i r a b l y s u i t e d f o r t h e f u t u r e f l e x i b l e management recommended by S m i t h ( 1 9 6 5 ) . An i n c r e a s i n g r o l e i n t h e economy f o r w e s t e r n h e m l o c k and w e s t e r n r e d c e d a r was f o r s e e n by Soos and W a l t e r s ( 1 9 6 3 ) , w h i c h was p a r t l y due t o t h e e x t e n s i v e r a n g e and a d a p t a -b i l i t y o f t h e two s p e c i e s . W e s t e r n h e m l o c k o c c u r s n a t u r a l l y w i t h D o u g l a s f i r and S i t k a s p r u c e (Wood, 1 9 5 5 ) , and m i x t u r e s a r e p r e -f e r r e d t o p u r e s t a n d s a c c o r d i n g t o A n d e r s o n ( 1 9 5 6 ) . T h e r e a r e s p e c i f i c f o r e s t r y p r o b l e m s o f how t o o p t i m i s e c o n d i t i o n s f o r g r o w t h . I le r . lock r e g e n e r a t i o n f r o m c l e a r - c u t t i n g young g r o w t h s t a n d s has n o t been s u c c e s s f u l ( H e r m a n , 1 9 6 2 ) : i t i s a d i f f i c u l t t r e e t o e s t a b l i s h a r t i f i c i a l l y ( W a l t e r s , 1 9 6 4 ) ; and i t i s n o t r ecommended as a p i o n e e r s p e c i e s on p e a t y o r h e a t h -l a n d s i t e s . ( Z e h e t m a y r , 1 9 5 4 , I 9 6 0 ) . B e c a u s e o f t h e s e d i f f i c u l t i e s i n e s t a b l i s h m e n t , s t a n d d e v e l o p m e n t i s e x c e p t i o n a l l y v a r i a b l e . T h e r e i s a need t o s t u d y t h e e n v i r o n m e n t a l f a c t o r s a f f e c t i n g e s -t a b l i s h m e n t ( R u t h , 1 9 6 8 ) , a f f e c t i n g g r o w t h and management ( W o o l d r i d g e , 1 9 6 1 ) , and t h e f l e x i b i l i t y o f t h e s p e c i e s u n d e r d i f -f e r e n t s t a n d d e n s i t y r e g i m e s ( M a l m b e r g , 1 9 6 5 ) . 4 • —— C o a s t a l w e s t e r n h e m l o c k i s d e f i n e d as h e m l o c k o c c u r r i n g o n , o r f r o m , t h e P a c i f i c c o a s t up t o an e l e v a t i o n o f -3 ,000 f e e t a . s . l . , and e x c l u d i n g i n t e r i o r w e s t e r n h e m l o c k , t h a t f r o m t h e C a s c a d e s , and f r o m t h e t r u e f i r / w e s t e r n h e m l o c k a s s o c i a t i o n s . 3 B. The p r o b l e m A s u m m a t i o n o f t h e p r o b l e m i s g i v e n i n t h r e e q u e s t i o n s and one s t a t e m e n t b e l o w . The o b j e q t i v e s o f t h i s d i s s e r t a t i o n a r e t o p r o v i d e some a n s w e r s t o t h e s e q u e s t i o n s - p r i m a r i l y t h o s e r e l a t e d t o p a r a m e t e r s o f s t o c k i n g and s t a n d d e n s i t y . C l i m a t i c f a c t o r s have n o t been s t u d i e d , and e d a p h i c and e c o l o g i c a l f a c t o r s a r e o n l y i n t r o d u c e d i n d i r e c t l y i n s i t e c l a s s i f i c a t i o n s . E m p h a s i s has been p l a c e d on a b o v e - g r o u n d c o m p e t i t i o n , me thods o f i t s m e a s u r e -m e n t , and i t s s i g n i f i c a n c e i n a f f e c t i n g t h e g r o w t h o f t r e e s and s t a n d s o f w o s t e r n h e m l o c k . P e r s o n a l i n v e s t i g a t i o n s have been s u p p l e m e n t e d w i t h a d d i t i o n a l p u b l i s h e d and u n p u b l i s h e d i n f o r m a t i o n i n an e f f o r t t o p r e s e n t a c o m p r e h e n s i v e a n a l y s i s o f t h e e n t i r e s u b j e c t . The t h r e e q u e s t i o n s i n c l u d e : i ) What i s t h e n a t u r a l v a r i a t i o n i n s t a n d d e v e l o p m e n t o f c o a s t a l w e s t e r n h e m l o c k ? R e p r o d u c t i o n o f w e s t e r n h e m l o c k o v e r any a r e a i s v a r i a b l e . T h e r e a r e i n d i v i d u a l t r e e s , s m a l l c l u m p s o f t r e e s w i t h two o r t h r e e s t e m s , and l a r g e r a g g r e g a t i o n s o f s t e m s . B o t h b e t w e e n and w i t h i n t h e s e c l u m p s t h e r e i s c o n s i d e r a b l e v a r i a b i l i t y i n a g e , s i z e , ' a n d g r o w t h r a t e . V a r i a b i l i t y b e t w e e n t r e e s i n p l a n t a t i o n s was a l s o n o t e d by H i l e y ( 1 9 5 0 ) . W e s t e r n h e m l o c k s o m e t i m e s r e p r o d u c e p r o l i f i c a l l y and j u v e n -i l e s t a n d s ( a g e s 5 t o 15 y e a r s ) may c o n t a i n more t h a n 1 5 , 0 0 0 s t e m s p e r a c r e . D o y l e - D a v i d s o n ( 1959 ) c o n s i d e r e d t h i s s i l v i c a l c h a r a c -t e r d a n g e r o u s , and i t i s c u r r e n t l y c o n s i d e r e d a s e r i o u s p r o b l e m 4 i n t h e P a c i f i c N o r t h w e s t ( W e s t e r n R e f o r e s t a t i o n C o o r d i n a t i n g C o m m i t t e e , 1 9 6 7 ) . W i t h i n t h e s e d e n s e s t a n d s i n d i v i d u a l t r e e g r o w t h i s v a r i a b l e . i i ) What c a u s e s t h e n a t u r a l v a r i a t i o n i n c o a s t a l w e s t e r n h e m l o c k s t a n d s ? T h e r e a r e t h r e e p r o b a b l e c a u s e s o f v a r i a t i o n i n s t a n d e s -t a b l i s h m e n t o f t h i s s p e c i e s . W e s t e r n h e m l o c k g e r m i n a t e s and g rows on a v a r i e t y o f s o e d - b e d s , b u t t h e r e a r e q u a n t i t a t i v e d i f -f e r e n c e s b e t w e e n t h e v a r i o u s b e d s . F u r t h e r m o r e , s u b s t r a t e s w h i c h e n h a n c e g e r m i n a t i o n and e a r l y s u r v i v a l a r e n o t n e c e s s a r i l y o p -t i m a l f o r s u b s e q u e n t g r o w t h . As s e e d - b e d t y p e s a r e s c a t t e r e d o v e r a f o r e s t a r e a , t h e i n i t i a l s t a n d e s t a b l i s h m e n t may p r o c e e d a t v a r y i n g r a t e s - d e p e n d i n g s i m p l y upon t h e d i s t r i b u t i o n o f 5 g r o w t h s u b s t r a t e s o f v a r i a b l e q u a l i t y . E v i d e n c e t h a t w e s t e r n h e m l o c k e s t a b l i s h e s i t s e l f b e s t on r o t t e n wood has been r e p o r t e d s i n c e t h e t u r n o f t h e c e n t u r y ( A l l e n , 1 9 0 2 ) . Some e x p l a n a t i o n s o f why t h i s h a p p e n s have been p r e s e n t e d by T a y l o r ( 1 9 3 5 ) , Garm ( 1 9 5 8 ) , and K r a j i n a ( 1 9 5 9 ) . G r o w t h o f w e s t e r n h e m l o c k t r e e s e s -t a b l i s h e d i n m i n e r a l s o i l has s o m e t i m e s been f o u n d s u p e r i o r t o t h a t o f t r e e s g r o w i n g on r o t t e n wood (Wa t son and B i l l i n g s l e a , 1 9 1 4 ) , a l t h o u g h W a l t e r s ( 1964 ) f o u n d t h e r e was a p o s i t i v e d i r e c t r e l a t i o n s h i p b e t w e e n h e i g h t g r o w t h and amount o f de composed s o i l o r g a n i c m a t t e r f o r p l a n t e d t r e e s . S e e d - b e d t y p e may have a s e c o n d , i n d i r e c t , e f f e c t upon s t a n d d e v e l o p m e n t . I r r e s p e c t i v e o f w h e t h e r op t imum g e r m i n a t i o n and g r o w t h o c c u r upon a s p e c i f i c s u b s t r a t e , t h e t r e e must c o m p e t e w i t h Q u a l i t y d e f i n e d h e r e as a b i l i t y t o e n h a n c e g e r m i n a t i o n and s u b s e q u e n t g r o w t h . 5 o t h e r p l a n t s on t h e s i t e . Few o t h e r t r e e s p e c i e s w i l l , o r c a n , grow on r o t t e n w o o d . S e e d l i n g s o f w e s t e r n h e m l o c k a r e f r a g i l e , r e l a t i v e l y s l o w g r o w i n g , and c o m p e t i t i o n - e s p e c i a l l y t h r o u g h v e g e t a t i o n demands on a v a i l a b l e m o i s t u r e - may r e l e g a t e w e s t e r n h e m l o c k t o r o t t e n wood ( B e r n s t e n , 1 9 5 5 ) . When w a t e r i s s u p p l i e d a r t i f i c i a l l y , and when c o m p e t i t i o n i s r e m o v e d , g r o w t h i s o p t i m u m v. i n f u l l s u n l i g h t ( R u t h , 1 9 6 8 ) , and on m i n e r a l s o i l ( L o g a n and S t i e l l , 19^9 ), or l i t t e r ( S u t t o n , 195^ ) • M o r t a l i t y of seed.lir.3s IG caused p r i m a r i l y by d r o u g h t and f r o s t h e a v i n g ( H e t h e r i n g t o n , 1 9 6 2 ; Soos and W a l t e r s , 1 9 6 3 ) . A t h i r d , more u n c e r t a i n c a u s e o f v a r i a t i o n i n d e v e l o p m e n t i s t h r o u g h t h e e f f e c t s o f t h e t r e e i t s e l f upon t h e m i c r o c l i m a t e . The c l u m p i n g o f w e s t e r n h e m l o c k , and t h e r a n g e o f ages f o u n d w i t h i n c l u m p s , s u g g e s t t h a t t h e p i o n e e r t r e e i s g r o w i n g upon a s u i t a b l e m i c r o s i t e and e n h a n c e s t h i s s i t e f o r c o n t i n u e d i n v a s i o n . S u c h a h y p o t h e s i s was a d v a n c e d by F e r g u s o n and B a s i l e ( 1967 ) t o a c c o u n t f o r i n c r e a s e d s u r v i v a l o f b i t t e r b r u s h w i t h i n c r e a s e d number o f e m e r g e n t s . Hemlock e x h i b i t s o p t i m u m g r o w t h on a s i t e when i t i s s h e l t e r e d . ( Z e h e t m a y r , I 9 6 0 ; S t e w a r t , 1 9 6 1 ) , and an age r a n g e o f 7 y e a r s was f o u n d by M a l m b e r g i n a s t a n d aged 15 y e a r s ( O s b o r n , 1 9 6 7 c ) . In a d d i t i o n t o t h e u n e v e n e s t a b l i s h m e n t , s t a n d d e v e l o p m e n t i s a l s o i r r e g u l a r due t o s e v e r a l f a c t o r s . W a t e r a v a i l a b i l i t y -d u r i n g t h e g r o w i n g s e a s o n c an be i m p o r t a n t . A l t h o u g h t r a n s p i r a -t i o n r a t e s i n w e s t e r n h e m l o c k t r e e s a r e r e p o r t e d t o be l o w ( K r a j i n a , 1 9 5 4 ) , i t has been f o u n d t h a t s i t e i n d e x i n c r e a s e d w i t h i n c r e a s e d a v a i l a b l e w a t e r and d e c r e a s e d p e r c e n t g r a v e l 6 ( B a j z a k , I 9 6 0 ; K o n k i n , 1 9 6 4 ; B a b a l o l a , 1 9 6 5 ) . P r o v i d e d t h e r e i s a d e q u a t e a v a i l a b l e m o i s t u r e g r o w t h may bo l i m i t e d by i n s u f f i -c i e n t s o i l n u t r i e n t s . A l t h o u g h t h e s p e c i e s i s c o n s i d e r e d s h a d e t o l e r a n t op t imum h e i g h t g r o w t h o c c u r s when t h e r e i s no o v e r h e a d c a n o p y ( S o o s , 1 9 6 1 ) . i i i ) How can t h e c a u s e s o f v a r i a t i o n be m a n i p u l a t e d ? M a n i p u l a t i o n i s r e q u i r e d t o f u l f i l management o b j e c t i v e s . E i t h e r t h e v a r i a t i o n i s t o be i n c r e a s e d , o r t o be d e c r e a s e d t o u n i f o r m i t y . In c e r t a i n c i r c u m s t a n c e s r e g e n e r a t i o n i s s u p e r a b u n -d a n t and must be r e g u l a t e d t o a d e s i r a b l e l e v e l . ^ A l t e r n a t i v e l y , a r e a s must be t r e a t e d t o s u p p l e m e n t i n i t i a l r e s u l t s . E c o n o m i c a n a l y s e s o f c u l t u r a l m e a s u r e s have been made ( F l o r a , 1 9 6 6 ; G r a h , I 9 6 0 ; G s b o r n , 1 9 6 8 a ; B e l i k , 1 9 6 8 ) , b u t o n l y a few have i n c l u d e d w e s t e r n h e m l o c k ( S m i t h et a l . . , 1 9 6 1 ; H o y e r , 1966 ) . C u l t u r a l o p e r a t i o n s w h i c h a f f e c t c a u s e s o f v a r i a t i o n i n -c l u d e ; a d d i t i o n o f o p t i m a l s e e d - b e d s u b s t r a t e ; i m p r o v e m e n t o f s u b - o p t i m a l s e e d - b e d s u b s t r a t e ; m o d i f i c a t i o n o f m i c r o c l i m a t e ; i n c r e a s e d s e e d s u p p l y . A c t u a l t e c h n i q u e s a r e : s l a s h - b u r n i n g , s c a r i f i c a t i o n , d r a i n a g e , f e r t i l i s a t i o n , weed c o n t r o l , a r t i f i -c i a l s e e d i n g and v a r i a b l e o v e r - s t o r e y t r e a t m e n t s l i k e s h e l t e r -wood r e g i m e s . A l l e n ( 1911 ) s t a t e d : " . . . h e m l o c k l e n d s i t s e l f t o a l m o s t e v e r y f o r m o f managemen t . D e t e r m i n a t i o n as t o w h i c h i s most a d v i s a b l e i s g o v e r n e d by i t s e x t r e m e l y v a r i a b l e manner o f o c c u r r e n c e and by t h e l o c a l p r o m i s e o f f e r e d by a s s o -c i a t e s p e c i e s . " D e s i r a b l e i n t e r m s o f s p e c i e s , n u m b e r , d i s t r i b u t i o n and s i z e o f t r e e s . 7 T h e r e i s no one op t imum r e g i m e , n o r s h o u l d t h e r e b e . M a n a g e -ment s h o u l d be f l e x i b l e b u t j u s t how p l i a b l e w e s t e r n h e m l o c k s t a n d s a r e must be a s s e s s e d . i v ) The i m p o r t a n c e o f s t o c k i n g and d e n s i t y i n c o n t r o l l i n g g r o w t h and y i e l d . A r e v i e w o f p a r t o f t h i s a s p e c t has a l r e a d y been p r e s e n t e d ( D s b o r n , 1 9 6 8 b ) , and t h e f o l l o w i n g s u m m a r i s e s t h i s p r e v i o u s i n -v e s t i g a t i o n . G r o w t h i n f o r e s t r y i s s ynonymous w i t h i n c r e m e n t -a n ' i n c r e a s e by a n a t u r a l p r o c e s s ( S p u r r , 1 9 5 2 ) , and y i e l d i s a f u n c t i o n o f i n i t i a l s i z e , r e l a t i v e g r o w t h r a t e , and l e n g t h o f t i m e ( W a t s o n , 1 9 5 2 ) . Any s i t e has a maximum c a p a c i t y t o s u p -p o r t p l a n t s , and t h i s c a p a c i t y i s d y n a m i c , v a r y i n g w i t h a t m o s -p h e r i c c h a n g e s , e d a p h i c c h a n g e s , s e a s o n a l v a r i a t i o n s , p l u s t h e e f f e c t s o f t h e v e g e t a t i o n i t s e l f upon t h e s i t e ( L e w i s , 1 9 5 9 ) . W h e t h e r t h e maximum s i t e c a p a c i t y i s " u s e d " d e p e n d s upon t h e e f f i c i e n c y .o f t h e v e g e t a t i o n . The r e l a t i v e g r o w t h r a t e i s d e -t e r m i n e d by i n d i v i d u a l t r e e e f f i c i e n c y and e f f e c t s o f i n t r a -s p e c i f i c c o m p e t i t i o n . S t a n d d e n s i t y , howeve r i t i s m e a s u r e d , i s u s e d t o d e s c r i b e c o m p e t i t i o n , o r c r o w d i n g , w i t h i n t h e o c c u -p i e d ( s t o c k e d ) p a r t o f t h e s i t e ( S m i t h and B a i l e y , 1 9 6 4 ) . Wa t t ( 1 9 5 9 ) s t r e s s e d t h a t t h e i n d e x o f p r o d u c t i v i t y ( y i e l d i n a s p e c i f i c t i m e p e r i o d ) must be c a r e f u l l y c h o s e n . Vo lume p e r u n i t a r e a a t a s p e c i f i c age i s o f p a r a m o u n t i m p o r t a n c e , b u t d i f f i c u l t i e s i n i t s d e t e r m i n a t i o n d e t r a c t f r o m i t s u s e f u l n e s s . S e v e r a l i n d i c e s , w h i c h a r e r e l a t e d t o v o l u m e p r o d u c t i o n , have been a d v o c a t e d i n c l u d i n g maximum h e i g h t ( T r o r e y , 1 9 3 2 ) , h e i g h t o v e r age ( S m i t h e_t aJL. , 1 9 6 1 ) , and h e i g h t g r o w t h w i t h b a s a l 8 a r e a p e r a c r e ( S m i t h , 1 9 6 7 a ) . A r e v i e w o f s i t e c l a s s i f i c a t i o n was made by Rowe ( 1 9 6 2 ) , and o f s i t e c a p a c i t y and p r o d u c t i v i t y by R o n n i e ( 1 9 6 2 ) and R a l s t o n ( 1 9 6 4 ) . C o n c l u s i o n s f r o m t h e s e p a p e r s were s i m i l a r t o t h a t s t a t e d by K r a j i n a ( 1 9 5 4 ) , t h a t s i t e c l a s s i f i c a t i o n can o n l y be t h o r o u g h l y e v a l u a t e d f r o m a s s e s s m e n t s o f t r e e g r o w t h , v e g e t a t i o n t y p e , and h a b i t a t f a c t o r s . A c c o r d -i n g t o Madgw i ck ( 1 9 6 7 ) , t h e s i m p l e m e a s u r e s o f h e i g h t and v o l -ume a r e n o t s u f f i c i e n t t o a d e q u a t e l y d e s c r i b e p r o d u c t i o n o f a w o o d l a n d . S t o c k i n g , e x p r e s s e d as a p e r c e n t a g e o f t o t a l a r e a , m e a s u r e s t h e a r e a o f a s i t e a c t u a l l y c o v e r e d and u t i l i s e d ( above t h e g r o u n d ) by t h e v e g e t a t i o n . . S t o c k i n g r a n g e s f r o m 0 t o 100 p e r c e n t when c r o w n s t o u c h . I t i s p a s s i b l e t h a t r o o t c o m p e t i -t i o n may d e t e r m i n e t h e u p p e r l e v e l o f s t o c k i n g , and on c e r t a i n p a r t i c u l a r l y d r y s i t e s 100 p e r c e n t c r o w n c l o s u r e ( f u l l s t o c k -i n g ) i s n o t n a t u r a l l y a t t a i n a b l e . D i f f i c u l t i e s i n m e a s u r i n g r o o t c o v e r a g e and a r e a o c c u p a t i o n p r e c l u d e t h e u se o f r o o t c o m p e t i t i o n as a f a c t o r i n p r a c t i c a l a s s e s s m e n t s o f s t o c k i n g . S t o c k i n g has ' ye t to" be d e s c r i b e d t h r e e - d i n c n s i o n a l l y , and i t i s o n l y r e c e n t l y t h a t t h i s has h a p p e n e d w i t h s t a n d d e n s i t y m r j a s u r e m e n t s . A r e a o c c u p a n c y l e s s t h a n 100 p e r c e n t w i l l c a u s e a r e d u c t i o n i n y i e l d p e r u n i t a r e a " ( C r a n e , 1 9 6 2 ) . Once f u l l s t o c k i n g has been a t t a i n e d , an i n c r e a s e d num-b e r a n d / o r s i z e o f t h e t r e e s c a u s e s c r o w d i n g w i t h i n t h e s t a n d , and c o m p e t i t i o n o c c u r s . U l t i m a t e l y t h e r e i s s u f f i c i e n t c r o w d -i n g t h a t g r o s s g r o w t h b a l a n c e s m o r t a l i t y , i . e . whe re s i t e f a c -t o r s a r e u s e d f o r m a i n t e n a n c e o n l y ( L e w i s , 1 9 5 9 ) . C r o w d i n g 9 b e y o n d t h i s p o i n t i s p o s s i b l e f o r s h o r t c l i m a t i c a l l y f a v o u r a b l e p e r i o d s b u t t h e s t a n d i s i n an u n s t a b l e c o n d i t i o n , and i r r e g u l a r , f r e q u e n t l y " c a t a s t r o p h i c " m o r t a l i t y w i l l i n e v i t a b l y o c c u r . T h i s e x t r e m e l y c r o w d e d and o f t h e s t a n d d e n s i t y s p e c t r u m has n o t been a d e q u a t e l y s t u d i e d t o d a t e . Maximum y i e l d i s a t t a i n e d f r o m a s t a n d d e n s i t y b e t w e e n t h e e x t r e m e s o f open and v e r y d e n s e ( C r a n e , 1 9 6 2 ) . T h e r e may be a v e r y n a r r o w p l a t e a u ( A s s m a n n , 1 9 6 1 ) , o r a r e l a t i v e l y w i d e r a n g e o f d e n s i t y w i t h i n w h i c h a b s o l u t e p r o d u c t i o n i s u n i f o r m ( M a r ; M o l l e r e t a 1 . , 1 9 5 4 ) . T h e s e h y p o t h e s e s a r e a l s o a d v o c a t e d i n a g r i c u l t u r e ( B l a c k , 1 9 6 5 ; B l e a s d a l e , 1 9 6 6 ) . The i n f l u e n c e o f s t a n d d e n s i t y upon g r o w t h and y i e l d i n w e s t e r n h e m l o c k i s i m p o r t a n t i n two w a y s . In a s h a d e t o l e r a n t c o n i f e r , p r o d u c t i v i t y s h o u l d i n c r e a s e w i t h i n c r e a s e d s t a n d d e n -s i t y . T h i s has been f o u n d by B a s k e r v i l l e ( 1 9 6 5 a ) f o r b a l s a m f i r i n s t a n d s up t o 5 , 0 0 0 s t e m s p e r a c r e . A s i m i l a r f i n d i n g was r e p o r t e d by C u r t i s ( 1965 ) f o r D o u g l a s f i r , b u t w h e t h e r t h i s i s t r u e f o r w e s t e r n h e m l o c k i s u n c e r t a i n . F u r t h e r m o r e , t h e u p -p e r l i m i t o f s t a n d d e n s i t y has s t i l l t o be d e f i n e d . The s e c o n d f e a t u r e o f i m p o r t a n c e i s w h e t h e r t h e i n c r e a s e d y i e l d , i f i t e x -i s t s , i s o f any n e t v a l u e . B a s k e r v i l l e o b t a i n e d t h e g r e a t e s t t o t a l w e i g h t p r o d u c t i o n f r o m s t a n d s w i t h t h e g r e a t e s t number o f t r e e s , b u t s m a l l i n d i v i d u a l t r e e s a r e e x p e n s i v e t o h a n d l e . I f t h i s h i g h e r p r o d u c t i v i t y c a n be a t t a i n e d w i t h f e w e r , l a r g e t r e e s , d e n s e s t a n d s may be d e s i r a b l e . In c o n t r a s t , i t has been f o u n d t h a t a b s o l u t e p e r i o d i c g r o w t h r a t e s o f y o u n g w e s t e r n h e m l o c k t r e e s i n r e l a t i v e l y open s t a n d s a r e f a r s u p e r i o r t o t h o s e i n 10 d o n s e s t a n d s , and that- t o t a l s t a n d i n c r e m e n t and y i e l d a r e o n l y s l i g h t l y r e d u c e d ( M a l m b e r g , 1 9 6 5 ) . A l t h o u g h v o l u m e p r o d u c t i o n i s s l i g h t l y r e d u c e d , v a l u e p r o d u c t i o n i s f a r h i g h e r i n t h e l e s s d e n s e s t a n d s . E c o n o m i c s t u d i e s have shown t h e b e n e f i t s o f i n i t i a l l y open d e n s i t y g r o w t h r e g i m e s ( G r a h , I 9 6 0 ; S m i t h et, a l . , 1 9 6 1 , S m i t h , 1 9 5 8 ; H a l e y , 1 9 6 4 b ; O s b o r n , 1 9 6 7 d ; O s b o r n , 1 9 6 8 a ) . C . S o u r c e s o f d a t a A p a r t f r o m t h e o v e r a l l s t a n d g r o w t h d a t a ( C h a p t e r 8) a l l i n f o r m a t i o n was t a k e n f r o m o r n e a r t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a ( U . B . C . ) R e s e a r c h F o r e s t n e a r H a n e y , B . C . G e n e r a l r e f e r e n c e s d e s c r i b i n g t h i s a r e a and i t s i m m e d i a t e e n v i r o n s i n -c l u d e t h o s e o f : J . E . A r m s t r o n g ( 1957 ) - g e o l o g y ; L a c a t e ( 1965 ) - p h y s i o g r a p h y ; L e s k o ( 1961 ) - s o i l s ; G r i f f i t h ( 1960 ) - c l i m a t e and s o i l ; B a j z a k ( I 9 6 0 ) - s i t e q u a l i t y ; E i s ( 1962 ) - f o r e s t h a b i t a t s ; O r l o c i ( 1 9 6 1 , 1 9 6 4 ) - v e g e t a t i o n ; K r a j i n a ( 1965 ) -b i o g e o c l i m a t i c s i t e c l a s s i f i c a t i o n ; U . B . C . F o r e s t C o m m i t t e e ( 1959 ) - management and p o l i c y ; W a l t e r s and T e s s i e r ( I 9 6 0 ) -h i s t o r y . Tha R e s e a r c h F o r e s t i s s i t u a t e d 35 m i l e s e a s t o f V a n c o u v e r , B . C . , i n t h e f o o t h i l l s o f t h e C o a s t m o u n t a i n s . E l e v a t i o n w i t h -i n t h e f o r e s t r a n g e s f r o m 5 f e e t a b o v e s e a l e v e l t o 2 , 6 0 0 f e e t , o r t o 3 , 2 0 0 f o e t w i t h i n t h e " e x t e n s i o n " ( s e e A p p e n d i x I . B . ) . Maximum a l t i t u d i n a l , l i m i t o f s e c o n d - g r o w t h t i m b e r w i t h i n t h e f o r e s t i s 2 , 8 5 0 f e e t . T o t a l a r e a i n B l o c k I i s a p p r o x i m a t e l y 1 0 , 0 0 0 a c r e s . B l o c k I I c o n t a i n s a b o u t 2 , 8 0 0 a c r e s . The e n t i r e f o r e s t i s w i t h i n 5 e c t i o n C . 2 o f R o w e ' s ( 1 9 5 9 ) F o r e s t R e g i o n s o f C a n a d a , and e m b r a c e s b o t h (wet and d r y ) s u b z o n e s o f K r a j i n a ' s 11 ( 1 9 6 5 ) b i o g e o c l i m a t i c C o a s t a l w e s t e r n h e m l o c k z o n e o f B r i t i s h C o l u m b i a . i ) E s t a b l i s h m e n t F i v e s i t e t y p e s we re d e l i m i t e d ( T a b l e 1) and two a r e a s w i t h i n e a c h t y p e were s t u d i e d . A l l f i v e t y p e s were w i t h i n Land A s s o c i a t i o n B o f L a c a t e ' s ( 1965 ) p h y s i o g r a p h i c c l a s s i f i c a t i o n o f t h e R e s e a r c h F o r e s t . T h i s A s s o c i a t i o n c h a r a c t e r i s e s 4 3 . 9 p e r c e n t o f t h e t o t a l f o r e s t a r e a and o c c u p i e s t h e more a c c e s -s i b l e l o w e r e l e v a t i o n s i t e s t h a n Land A s s o c i a t i o n A ( o c c u p y i n g 4 2 . 5 p e r c e n t o f t h e f o r e s t a r e a ) . L and A s s o c i a t i o n s a r e a g g r e g a t i o n s o f g e o g r a p h i c a l l y a s s o c i a t e d Land U n i t s , and t h e l a t t e r a r e homogenous s e g m e n t s o f t h e l a n d s u r f a c e w h i c h have c h a r a c t e r i s t i c t o p o g r a p h i c f o r m and i n t e r n a l g e o l o g i c s t r u c t u r e . L and U n i t s a r e a s s o c i a t e d w i t h d i s t i n c t i v e t y p e s o f s o i l and v e g e t a t i o n . F o u r L a n d A s s o c i a t i o n s were r e c o g n i z e d on t h e R e s e a r c h F o r e s t and A and B were b o t h composed o f g l a c i a l t i l l o v e r b e d r o c k . P r i m a r i l y t h e d i f f e r e n t i a t i o n ' o f L a n d A s s o c i a t i o n A f r o m L a n d A s s o c i a t i o n B s e p a r a t e s t h e s t e e p r o c k y l a n d s (A) f r o m t h e more a c c e s s i b l e and p r o d u c t i v e ( B ) . The t e n s a m p l e a r e a s w e r e a l l on t h e b o u n d a r y b e t w e e n t h e l o w e l e v a t i o n d r y s u b z o n e and t h e u p p e r wet s u b z o n e . B a s i c s t a t i s t i c s o f e a ch a r e a and s a m p l e t r e e s a r e g i v e n i n T a b l e 2 . The l o c a t i o n o f e a ch s a m p l e a r e a i s g i v e n i n A p p e n d i x I.B.-i i ) G r o w t h o f j u v e n i l e t r e e s In 1 9 5 7 , s p a c i n g t r i a l s w i t h D o u g l a s f i r , w e s t e r n h e m l o c k and w e s t e r n r e d c e d a r were i n i t i a t e d ( P r o j e c t 57-5 ) ( R e p o r t , 12 T a b l e 1 S i t e Type 1 V e r y good 2 Good Seepage C h a r a c t e r i s t i c s o f s i t e t y p e s f o r e s t a b l i s h m e n t s t u d y . V e g e t a t i o n i n d i c a t o r s P o l y s t i c h u m R u b u s P t e r i d i u m B l e c h n u m Moss" 3" .FLubas, P t e r i d i u m S o i l d e p t h and w a t e r r e l a -t i o n s ^ -V e r y deep s o i l w i t h p e r m a n e n t s e e p a g e Medium s o i l d e p t h w i t h good s e e p a g e S i t e I n d e x w e s t e r n h e m l o c k 130 121 S i t e I n d e x D o u g l a s f i r 161 138 3 Medium 4 P o o r Wet 5 P o o r D r y V a c c i n i u m Moss V a c c i n i u m  L v s i c h i t u m T h u i a S a l a l V a c c i n i u m Medium s o i l d e p t h and 106 f r e e l y - d r a i n e d s o i l V e r y wet w a t e r -l o g g e d muck 96 s o i l S h a l l o w d r y 58 s o i l 120 72 ' b a s e d upon h e r b a c e o u s i n d i c a t o r s , n a t u r a l p r o f i l e s , r o o t i n g p a t t e r n s , and r e s u l t s o f E i s ( 1 9 6 2 ) . " a d a p t e d f r o m E i s ( 1962 ) ( f e e t a t 100 y e a r s ) . p r i m a r i l y P l a q i o t h e c i u m u n d u l a t u m . 13 T a b l e 2 B a s i c s t a t i s t i c s o f a r e a s and s a m p l e t r e e s i n e s t a b l i s h m e n t s t u d y . S i t e t y p e Samp le number Age s a m p l e y e a r s Age o p e n -grown y e a r s E l e v a -t i o n f e e t Aspe c t S l o p o p e r c e n t S o i l 1 C l a s s " S . I . 2 f e e t a t 100 y e a r s 1 3.1 17 14 1 , 2 0 0 E 5 3 d i / l ISO-3 .3 14 16 1 , 2 0 0 E 25 3 d i - d / m ISO 2 3 .2 14 14 1 , 220 NE 25 3 d i - d / m 130 4 . 1 7 7 1 , 1 5 0 5 10 2d/m/b 110 3 . 1 .2 16 8 1 , 1 1 0 5 0 2d/m/b 130 2 .1 4 4 1 , 1 5 0 5 5 2-3d/m/b 110 2 .2 6 5 1 , 1 5 0 5E 0 2-3d/m/b 110 2 .3 4 4 1 , 1 5 0 S 0 2-3d/m/b 110 4 2 .4 7 4 1 , 1 6 0 NE~ 0 2d/m/b 110 2 . 5 6 6 1 , 1 6 0 NE 0 2d/m/b 110 2 . 6 6 9 1 , 1 6 0 SE 0 4-5w/m/k 110 5 1.1 9 9 1 , 0 2 5 SE 10 l - 2 d / m / b 110 5.1 8 7 1 , 2 2 5 SE 5 > 2d/m/b 130 5 .2 6 8 1 , 2 2 5 SE 5 2d/m/b 130 ^ s o i l 2 • + s x t e m o i s t u r e c l a s s i f i c a t i o n i n d e x f r o m B a j z a k ( I 9 6 0 ) f r o m L a c a t e f o r D o u g l a s (1965 ) . f i r . 1 9 6 1 ' ) . One h a l f - a c r e o f w e s t e r n h e m l o c k -at 3 x 3 f e e t s p a c i n g was p l a n t e d ( P l a n t a t i o n 3 4 ) , and a r e p l i c a t e d (2 r e p l i c a t e s ) b l o c k o f 0 . 5 6 a c r e s i n c l u d i n g s q u a r e s p a c i n g s a t 3 , 6 , 9 , 1 2 , and 15 f s e t was s p o t - s e e d e d w i t h 49 t r e e s i n e a c h e x p e r i m e n t a l u n i t e x c e p t t h e c l o s e s t w h i c h c o n t a i n e d 98 s e e d - s p o t s ( P l a n t a -t i o n 2 1 ) . L o c a t i o n o f t h i s e x p e r i m e n t i s g i v e n i n A p p e n d i x I . B . , and t h e a v e r a g e s i t e i n d e x f o r D o u g l a s f i r b e f o r e l o g g i n g was 170 ( W a l t e r s , 1 9 6 4 ) . Young n a t u r a l r e g e n e r a t i o n f r o m s e v e r a l T h r o u g h o u t t h i s d i s s e r t a t i o n " R e p o r t " r e f e r s t o A n n u a l R e p o r t s o f t h e U . B . C . R e s e a r c h F o r e s t w i t h t h e a p p r o p r i a t e y e a r o f p u b l i c a t i o n . 14 l o c a t i o n s was a l s o s a m p l e d f o r a n a l y s i s w i t h t h e s p a c i n g t r i a l d a t a , i n c l u d i n g t h e s a m p l e t r e e s i n t h e e s t a b l i s h m e n t s t u d y , i i i ) E a r l y s t a n d f o r m a t i o n The e a s t e r n t h i r d o f t h e R e s e a r c h F o r e s t d e v e l o p e d a f t e r l o g g i n g and w i l d f i r e s d u r i n g t h e 1 9 2 0 ' s and i n 1931 ( W a l t e r s and T e s s i e r , 1 9 6 0 ) . D e m a r c a t i o n o f t h i s a r e a i s g i v e n i n A p p e n d i x I . A , D u r i n g t h e summer o f 1 9 6 5 , i n c o n j u n c t i o n w i t h an i n v e n t o r y c r u i s e , s t a n d and t r e e d a t a were c o l l e c t e d . W i t h i n t h e 294 p o i n t s a m p l i n g l o c a t i o n s 213 i n c l u d e d w e s t e r n h e m l o c k , and 145 h e m l o c k t r e e s were m e a s u r e d i n d e t a i l , A f u r t h e r 74 t r e e s we re m e a s u r e d i n 1966 f r o m t h e same l o c a t i o n . D u r i n g 1947 t r e e s i n 17 1/250 a c r e p l o t s , and 11 1/1000 a c r e p l o t s we re m e a s u r e d i n d e t a i l by G . S . A l l e n . T h e s e d e n s e s t a n d s were l o c a -t e d i n N o r t h V a n c o u v e r . i v ) G r o w t h o f t r e e s i n young s t a n d s F o u r t e e n l / 5 0 t h a c r e p l o t s were e s t a b l i s h e d d u r i n g 1965 i n a r e l a t i v e l y d e n s e s t a n d o f w e s t e r n h e m l o c k as P r o j e c t 63-5d ( R e p o r t , 1 9 6 6 ) . N i t r o g e n f e r t i l i s e r , i n t h e f o r m o f N i t r a p r i l l s was a p p l i e d a t r a t e s o f 0 , 5 0 , 1 0 0 , 2 0 0 , and 400 pounds o f n i t r o g e n p e r a c r e . U r a m i t e and 1 0 - 8 - 6 a t 200 p o u n d s N p e r a c r e were f u r t h e r t r e a t m e n t s and e a c h e x p e r i m e n t a l u n i t was r e p l i c a -t e d t w i c e ( S m i t h e_t a l . , 1 9 6 8 ) . W i t h i n t h i s s t a n d ( l o c a t i o n i n A p p e n d i x I .B ) t e n t r e e s we re s t u d i e d - f i v e f e r t i l i s e d and f i v e u n f e r t i l i s e d - and e a c h s u b j e c t e d t o a d e t a i l e d s t e m a n a l y s i s ( 1 9 6 7 ) . T h r e e o f t h e s a m p l e t r e e s were f r o m P l o t 6 ( r e c e i v i n g 15 400 pounds N p u r a e r o ) and two were f r o m P l o t 14 (100 pounds p e r a c r e ) . The f o r m e r p l o t was on a 25 p e r c e n t s i d e s l o p e w i t h some l a t e r a l s e e p a g e w h e r e a s t h e l a t t e r was s i t e d i n a c r e e k b o t t o m w i t h some s u r f a c e w a t e r . A l l t h e u n f e r t i l i s e d t r e e s were a d j a c e n t t o t h e f e r t i l i s e r p l o t s . An a d d i t i o n a l f i v e s a m p l e t r e e s were m e a s u r e d f r o m s t a n d s w h i c h had been f e r t i l i s e d i n 1 9 5 9 . The two p l o t l o c a t i o n s o f t h i s e x p e r i m e n t ( P r o j e c t 59-1 ) a r e shown i n A p p e n d i x IiB« A d e s c r i p t i o n of. t h e e x p e r i m e n t has been g i v e n ( R e p o r t , 1 9 6 1 ) and an a n a l y s i s o f t h e e f f e c t s o f t h i n n i n g and f e r t i l i s a t i o n c o m -p l e t e d by M a r l o w ( 1 9 6 6 ) . R e c o r d s f r o m a t h i n n i n g e x p e r i m e n t e s t a b l i s h e d i n 1950 were a l s o u s e d ( G r i f f i t h , 19 .59 ) . T h e s e d a t a were a n a l y s e d t o a s s e s s e f f e c t s o f c o m p e t i t i o n on t r e e and s t a n d g r o w t h . v ) G r o w t h o f t r e e s i n m i d d l e - a g e d s t a n d s D u r i n g t h e summer o f 1 9 6 6 , 187 t r e e s on t h e R e s e a r c h F o r -e s t we re m e a s u r e d , and 80 o f t h e s e were more t h a n 40 y e a r s o l d . S t r a t i f i c a t i o n was by age c l a s s ( 1 0 , 3 0 , 6 0 , 9 0 , and 120 y e a r s ) , s t a n d d e n s i t y ( 6 0 , 1 2 0 , 2 4 0 , 3 6 0 , and 480 s q u a r e f e e t p e r a c r e ) , c r o w n c l a s s ( d o m i n a n t , c o d o m i n a n t , i n t e r m e d i a t e and s u p p r e s s e d ) , and s i t e c l a s s ( p o o r d r y , p o o r w e t , m e d i u m , good s e e p a g e , and v e r y good ) . T r e e s f r o m t h e o l d e r t h r e e age c l a s s e s were a l l l o c a t e d i n t h e w e s t e r n and c e n t r a l p a r t o f t h e R e s e a r c h f o r e s t , a l l b o l o w t h e 1 , 5 0 0 f o o t c o n t o u r , and were n o t f o u n d i n s t a n d s See c l a s s i f i c a t i o n i n T a b l e 1 . i T a b l Age c l a s s ( y e a r s ) P P M G V P P M G V ' P P M G V P . P M G V . P P M G V T o t a l s c l a s s e s 10 30 60 120 i 3 51 r a 4-u ..v. f i c 31 i on o f U . B . C . R e s e a r c h F o r e s t a n d C l a s s e s S a m p l e d . Crown B a s a l a r e a pe r a c r e ( s q u a r e f e e t ) 2 c l a s s 60 120 S i t e ' 240 . c l a s s 4 360 480    a   P M G V P P M G V  P    P P M G M D •W b G D •w S G D W S G D W 5 G D W S G D + + * + + + + + CD +• + * + + + + + I + H- + + + + + + 5 + !- + + + + + D + + H • + + + + + + + + + + + + + + + CD * + + + + + + * + + + + + + + + + I + + + + + + + + + + + + + + + + + + 5 + + + + + + + + + + + + + + + + D - + + + + + + + + CD + + + + + + I + + + + + + + S + D + + + + + + + + CD + + + + + + + + * + + + I . + + + + + + + + + + + + 5 + + D + * + + + CD + + + + + + I + + 4 s i t e c l a s s e s as g i v e n i n T a b l e 1 . 31 71 25 90 " . . . . . . . . . ^ . , . 37 14 a + r e p r e s e n t s one t r e e s a m p l e d ; * r e p r e s e n t s two t r e e s s a m p l e d . 2 b a s a l a r e a p e r a c r e n o t a p p l i c a b l e t o t h e t e n - y o a r - o l d s where s t r a t a were s q u a r e s p a c i n g a t 3 , 6, 3, 12, and 15 f e e t . 3 where D = d o m i n a n t , CD = c o d o m i n a n t , I = i n t e r m e d i a t e , S = s u p p r e s s e d . 17 o f t h e g r e a t e s t d e n s i t y . A summary o f t h e c l a s s e s p o s s i b l e and t h o s e a c t u a l l y s a m p l e d i s g i v e n i n T a b l e 3 . Soma a s p e c t s o f t h e s e d a t a have been a n a l y s e d by Ch iam ( 1 9 6 7 ) . v i ) G r o w t h o f w e s t e r n h e m l o c k s t a n d s D a t a f r o m p e r m a n e n t g r o w t h and y i e l d p l o t s we re s u p p l i e d f r o m s e v e r a l a u t h o r i t i e s . I n c l u d e d were r e s u l t s f r o m t h e B r i t i s h C o l u m b i a F o r e s t S e r v i c e , t h e U n i t e d S t a t e s F o r e s t 5 e r v i c e , t h e F o r e s t r y C o m m i s s i o n o f G r e a t B r i t a i n , and p r i v a t e c o m p a n i e s i n V a n c o u v e r . v i i ) E s t i m a t i o n o f m o r t a l i t y W i t h i n t h e s a m p l i n g d e s c r i b e d i n s e c t i o n v) a b o v e numbers o f dead t r e e s i n f i x e d r a d i u s p l o t s we re r e c o r d e d , b,ut c a u s e o f m o r t a l i t y was n o t a s c e r t a i n e d . P e r m a n e n t s a m p l e p l o t r e c o r d s a l s o i n c l u d e d e s t i m a t e s o f m o r t a l i t y . D . M e t h o d s o f - a n a l y s i s i ) D e s c r i p t i v e A l l a n a l y s e s a r e c o m p a r e d w i t h t h o s e c i t e d by o t h e r a u t h o r i -t i e s . The s c o p e o f t h i s s t u d y d i d n o t p e r m i t a c o m p l e t e i n -v e s t i g a t i o n i n t o many o f t h e f a c e t s o u t l i n e d a b o v e , and d e s c r i p -t i v e a n a l y s i s t o g e t h e r w i t h r e l e v a n t l i t e r a t u r e has been u s e d whe re p e r s o n a l r e s u l t s a r e n o t s u f f i c i e n t t o w a r r a n t m a t h e m a t i c a l t r e a t m e n t . T h i s i s e s p e c i a l l y p e r t i n e n t i n t h e s e c t i o n s on e s t a b l i s h m e n t and m o r t a l i t y . 18 i i ) M e a s u r e m e n t s t a k e n , a) E x t e r n a l p h y s i c a l m e a s u r e m e n t s S i t e and i n d i v i d u a l t r e e m e a s u r e m e n t s were made i n e s t a -b l i s h m e n t i n v e s t i g a t i o n s . E a ch a r e a was mapped to , show s i z e o f c l u m p s as w e l l as s e e d - b e d t y p e and h e m l o c k t r e e d i s t r i b u t i o n . H e i g h t , d i a m e t e r and c r o w n s i z e o f s a m p l e t r e e s were m e a s u r e d 9 t o compa re o p e n - g r o w n and c r o w d e d t r e e s . H e i g h t a n d age r a n g e w i t h i n e a ch c l u m p s a m p l e d were r e c o r d e d . A n n u a l g r o w t h r a t e s o f b o t h t h e t e r m i n a l s h o o t and t h e two o p p o s i t e l o n g e s t b r a n c h e s were r e c o r d e d . J u v e n i l e t r e e g r o w t h was d e t e r m i n e d f r o m s t a n d m e a s u r e m e n t s o f s i t e and s p a c i n g , and f r o m t r e e m e a s u r e m e n t s o f h e i g h t , d i a m e -t e r , b r a n c h , and c r o w n s i z e . D i s t a n c e t o , and s i z e o f c o m p e t i -t o r s were a l s o r e c o r d e d . M e a s u r e m e n t s f o r e a r l y s t a n d f o r m a t i o n i n c l u d e d d e t e r m i n a -t i o n s o f " s t a n d " p o i n t d e n s i t y ( b a s a l a r e a p e r a c r e ) and d e t a i l e d t r e e s i z e m e a s u r e m e n t s (1965 r e s u l t s ) . A d e s c r i p t i o n o f t h e f i e l d t e c h n i q u e s and an i n i t i a l a n a l y s i s was g i v e n by G s b o r n ( 1 9 6 6 b ) . Of t h e 187 t r e e s s a m p l e d i n 1 9 6 6 , 74 we re i n t h e 3 0 -y e a r age c l a s s and m e a s u r e m e n t s i n c l u d e d t h o s e o f s i t e , s t a n d d e n s i t y , c r o w n c l o s u r e , t r e e s i z e and b r e a s t - h e i g h t d i a m e t e r u n d e r - b a r k g r o w t h r a t e . D a t a f r o m t h e t h i n n i n g e x p e r i m e n t s i n -c l u d e d number o f t r e e s , d . b . h . , and h e i g h t . A l l e n ' s d a t a i n c l u -ded b r e a s t - h e i g h t d i a m e t e r , age and c rown c l a s s o f e v e r y t r e e i n t h e p l o t . H e i g h t and r a d i a l g r o w t h o f s e v e r a l s a m p l e t r e e s were a l s o r e c o r d e d , w i t h an e s t i m a t i o n o f l i v e c r o w n l e n g t h . F r e e f r o m a b o v e - g r o u n d ' c o m p e t i t i o n . 19 E x t e r n a l d i m e n s i o n s - o f a l l 15 s a m p l e t r e e s were m e a s u r e d b e f o r e f e l l i n g and d e t a i l e d s t a n d d e n s i t y and c o m p e t i t i o n m e a -s u r e m e n t s were r e c o r d e d i n t h e 1967 s t u d i e s . The d i s t a n c e t o , s i z e o f , and g r o w t h r a t e s o f a l l t r e e s c o m p e t i n g w i t h t h e s a m p l e t r e e s were d e t e r m i n e d . S amp l e t r e e s were f e l l e d and b u c k e d i n t o m e t r e l e n g t h s . L i v e c r o w n w i d t h o f each b o l t was m e a s u r e d and t h e number o f b r a n c h e s ^ c o u n t e d . D i s c s were c u t f r o m t h e b a s e o f e a ch b o l t f o r g r o w t h and d r y w e i g h t d e t e r m i n a t i o n s . The m e t r e l e n g t h and t h e b r a n c h e s f r o m i t were w e i g h e d ( g r e e n ) s e p a r a t e l y on a beam b a l a n c e . T e r m i n a l s e c t i o n s r a n g e d f r o m 6 . 3 t o 1 2 . 0 f e e t i n l e n g t h . I n i t i a l s a m p l i n g p r o c e d u r e and e x t e r n a l m e a s u r e -ments r e c o r d e d a r e g i v e n i n F i g u r e 1 and d e t a i l s o f s u b - s a m p l i n g w i t h i n e a c h b o l t ' s l o n g e s t b r a n c h a r e g i v e n i n F i g u r e 2 . The e x t e n t o f s a m p l i n g o f m i d d l e - a g e d s t a n d s i s i n d i c a t e d i n T a b l e 3 . S t a n d m e a s u r e m e n t s i n c l u d e d p r i s m sweeps a r o u n d e a c h s a m p l e t r e e , o c u l a r e s t i m a t e s o f c rown c l o s u r e , f i x e d r a d i u s p l o t e n u m e r a t i o n s o f s t ems p e r a c r e , ( a l l t r e e s o f 0 .1 i n c h d . b . h . and l a r g e r ) and m e a s u r e m e n t s o f r e l a t i v e l i g h t i n t e n s i t y . The l a t t e r m e a s u r e m e n t s were made w i t h a G o s s e n L u n a a i x e x p o s u r e m e t e r h e l d v e r t i c a l l y a t b r e a s t - h e i g h t , e q u i d i s t a n t b e t w e e n a s a m p l e t r e e and i t s n e a r e s t c o m p e t i t o r , b u t a v o i d i n g s u n - f l e c k s . A r e a d i n g w i t h i n t h e s t a n d was f o l l o w e d i m m e d i a t e l y by one i n f u l l l i g h t . The s c a l e on t h e e x p o s u r e m e t e r was c a l i b r a t e d a g a i n s t a l i g h t m e t e r i n t h e l a b o r a t o r y t o d e t e r m i n e f o o t - c a n d l e v a l u e s f o r t h e f i e l d . O c u l a r c r o w n c l o s u r e e s t i m a t e s were c h e c k e d by p h o t o g r a m m e t r i c m e a s u r e m e n t s as d e t a i l e d by Ch i am "*"^ A b r a n c h was d e f i n e d as a l a t e r a l a p p e n d a g e l o n g e r t h a n one f o o t . 20 Section Code Measure Weigh Sample Retained 16 Se 14-4 _I6_D_ 15 Se 15 D total height length of section mean CW 1 number of branches (3 live) cardinal direction of longest live branch stem section plus disc, branches disc, longest live branch mean CW l i v e ) number of branches (2 cardinal direction of longest live branch stem section plus disc branches disc, longest live branch 0 -0 H I 14 Se 14 0 mean CW live) number of branches (4 lowest live whorl cardinal direction of longest live branch stem section plus disc, branches disc, longest live branch o-7-8 13 Se 13 D mean CW live,I dead) number of branches ( 2 cardinal direction of longest live branch stem section plus disc, branches disc, longest live branch — 0 4 5 M/////////A. 12 Se 12 0 II Se mean C W 2 dead) number of branches (I live; lowest live branch cardinal direction of lojiajssXUvejbranch. number of branches (3 dead) 2 M//////////A JLP_ i st stem section plus disc, branches stem section plus disc, branches disc, longest live branch disc stump age stump Figure I- Initial sampling procedure in biomass studies-CW is crown width Butt f_ Large wood (dob- great-" er than 0-75 inches) Medium wood (average d o b 0-25-0-75 inches) ->U-Small wood I Tip (average d o b less than *j 0-25 inches) IPC Annual Increments M r length to branch mid-point total length-Measure1 total length, total green weight, butt d o b , butt d-ib,mid-point d ob.mid-point d-ib, length of increments, age of oldest needles, length of large wood, medium wood,and small wood-3 Oiscs Separately Measure^ green weight of wood,green weight of bark,volume of wood .volume of bark-3 Wood Classes Separately Measure:green weight of wood plus bark plus needles-> ' ( Dry to a Constant Weight at 105° C ) > r 3 Discs Separately Measure-dry weight of wood, dry weight of bark-3 Wood Classes Separately Measure: dry weight of wood plus bark, dry weight of needles-Measure -green weight of sample of needles Measure'-dry weight of sample of needles Figure 2- Longest branch sampling procedure- I i the entire branch was classified,not only the main shoot as diagrammed 22 ( 1 9 6 7 ) . D i s t a n c e t o b r e a s t - h e i g h t d i a m e t e r , and c r o w n w i d t h o f t h e f o u r t r e e s c o m p e t i n g w i t h t h e s a m p l e t r e e on t h e c a r d i n a l p o i n t s we re m e a s u r e d . In a l l p r i s m e s t i m a t e s o f b a s a l a r e a p e r a c r e t r e e s o f 0 .1 i n c h b r e a s t - h e i g h t d i a m e t e r and l a r g e r we re r e c o r d e d . b) I n t e r n a l p h y s i c a l m e a s u r e m e n t s R a d i a l i n c r e m e n t o f a l l s a m p l e and o p e n - g r o w n t r e e s i n t h e e s t a b l i s h m e n t s t u d y was m e a s u r e d a t r o o t - c o l l a r . B r e a s t -h e i g h t r a d i a l g r o w t h o f j u v e n i l e t r e e s o u t s i d e t h e s p a c i n g t r i a l was r e c o r d e d by f i v e y e a r i n t e r v a l s . A l l s t e m s s t u d i e d f o r d a t a on e a r l y s t a n d f o r m a t i o n were b o r e d a t b r e a s t - h e i g h t . A s i n g l e i n c r e m e n t c o r e was t a k e n f r o m t h e 145 t r e e s (1965 r e -s u l t s ) and f i v e - and t e n - y e a r r a d i a l i n c r e m e n t s r e c o r d e d . S i m i l a r r e s u l t s were c o l l e c t e d f r o m t h e 1966 s a m p l e s , w i t h f i v e y e a r i n c r e m e n t s up t o t w e n t y y e a r s ago m e a s u r e d . A l l i n -c r e m e n t c o r e s were m e a s u r e d w i t h a r u l e d i r e c t l y i n t h e f i e l d t o t h e n e a r e s t 0 .1 i n c h e s . The f i f t e e n t r e e s s t u d i e d u n d e r s e c t i o n i v ) above were m e a s u r e d i n g r e a t e r d e t a i l . C a r d i n a l d i r e c t i o n s were m a r k e d on e a c h s t e m d i s c . A v e r a g e d i a m e t e r , w i d t h , and w e i g h t o f e a c h d i s c were r e c o r d e d i n t h e l a b o r a t o r y on t h e day o f f e l l i n g . L i k e w i s e , r a d i a l i n c r e m e n t on e a c h c a r d i n a l r a d i u s was m e a -s u r e d as d i a g r a m m e d i n F i g u r e 3 . D i s c and b a r k v o l u m e s were c a l c u l a t e d f r o m l i n e a r m e a s u r e m e n t s and n o t by w a t e r d i s p l a c e -m e n t . A f t e r o v e n - d r y i n g a t 1 0 5 ° C . t o c o n s t a n t w e i g h t t h e m o i s t u r e c o n t e n t and a v e r a g e s p e c i f i c g r a v i t y o f e a ch d i s c and b a r k s a m p l e we re d e t e r m i n e d - s e e F i g u r e 3. Bark Radial Increment (R ! ) 0 - 5 years ago R-1- 6-10 years ago R-1- 11 — 15 years ago R-1- 16 — 20 years ago •R-l- 2 1 - p i t h •Total age of sample R-l' last year (1966) •R-l- 1965 R-l- 1964 R-l- 1963 R-l- 1962 'R-l- 1961 R-l- I960 Measurements recorded on all four radi Average width sample (8 measurements) Average d-i-b- (2 measurements) v ^ _ ; Average dob- ( 2 measurements) Meqsure DISC BARK Calculate DISC BARK Green Weight Oven-dry Weight GW DW Gw Dw Volume (green) Moisture Content 7 T / 4 (d-i-b-)2 =VD /GW — DW\K|rv> \ DW / 7T/4 (d o b ) 2 - V D = V b ^Gw-Dw^ | 0 Q SG-DW VD Dw Vb Figure 3- Measurements of stem sample in biomass study 24 Two b r e a s t - h e i g h t d i a m e t e r b o r i n g s were t a k e n f r o m e v e r y t r e e c o m p e t i n g w i t h t h e f i f t e e n s a m p l e t r e e s d e s c r i b e d a b o v e . B o r i n g s were t a k e n on t h e f a c e c l o s e s t t o t h e s a m p l e and on t h e o p p o s i t e s i d e . R a d i a l i n c r e m e n t was r e c o r d e d i n a c o m p a r a b l e f a s h i o n t o t h a t o f t h e s a m p l e t r e e d i s c s ( s ee F i g u r e 3 ) . c ) F o l i a r a n a l y s e s F o l i a g e s a m p l e s were c o l l e c t e d f r o m 119 t r e e s i n 1 9 6 6 , One s a m p l e was t a k e n f r o m each o f 97 t r e e s , two s a m p l e s e a ch t a k e n f r o m a f u r t h e r 21 t r e e s , and 15 s a m p l e s f r o m a s i n g l e t r e e . A p a r t f r o m t h e l a t t e r , s a m p l e s were c o l l e c t e d f r o m t h e l o n g e s t b r a n c h o f t h e t r e e and no n o t e was t a k e n o f i t s p o s i -t i o n i n t h e c r o w n , n o r were n e e d l e age s e g r e g a t i o n s made . C o l l e c t i o n was made f r o m June t o A u g u s t . The 119 t r e e s were p a r t o f t h e 187 t r e e s m e a s u r e d t o c o v e r t h e r a n g e o f a g e s , s i t e s , and s t a n d d e n s i t i e s g i v e n i n T a b l e 3 . S a m p l e s were f r o m a l l c r o w n c l a s s e s i n t h e y o u n g e r s t a n d s b u t f r o m c o d o m i -n a n t s and i n t e r m e d i a t e s i n t h e o l d e r s t a n d s where s a m p l e t r e e s were f e l l e d and n o t c l i m e d . F i f t e e n s a m p l e s f r o m a s i n g l e t r e e we re c o l l e c t e d a t f i v e f o o t i n t e r v a l s down t h e c rown b u t no age s e g r e g a t i o n was made. S a m p l e s o f f o l i a g e were a l s o c o l l e c t e d d u r i n g 1967 f r o m t h e t e n t r e e s i n t h e 1965 f e r t i l i s e r e x p e r i m e n t . A l l s a m p l e s were c o l l e c t e d d u r i n g May and e a r l y J une - b e f o r e f l u s h i n g -and were c a r e f u l l y s e g r e g a t e d by age and p o s i t i o n i n t h e c r o w n . S a m p l i n g p r o c e d u r e i s o u t l i n e d i n F i g u r e 4 . C o l l e c -t i o n o f n e e d l e s was made on t h e day o f f e l l i n g and wet day s were a v o i d e d where p o s s i b l e . Where t h e r e was i n s u f f i c i e n t Figure 4 - Folior analysis sampling procedure* 26 raw m a t e r i a l c l a s s e s were c o m b i n e d by p o s i t i o n i n t h e c r o w n and n o t by a g e . A t o t a l o f 159 s a m p l e s were c o l l e c t e d . Hand p i c k i n g o f t h e f o l i a g e e l i m i n a t e d b u d s , b a r k , and d i s e a s e d n e e d l e s . L e a v e s were- s e a l e d i n p o l y e t h y l e n e b a g s and p l a c e d i n c o l d s t o r a g e on t h e day o f c o l l e c t i o n . S a m p l e s were l a t e r d r i e d f o r 24 h o u r s a t 7 Q ° C , g r o u n d i n a W i l e y M i l l w i t h a 40 mesh s c r e e n (420 m i c r o n s ) , and d r i e d a f u r t h e r 24 h o u r s a t 7 0 ° C . A l l s a m p l e s were s h i p p e d t o T r a i l , B . C . , and a n a l y s e d by C o m i n c o L t d . f o r n i t r o g e n , p h o s p h o r u s , p o t a s -s i u m , c a l c i u m , m a g n e s i u m , and s u l p h u r c o n t e n t . A n a l y t i c a l p r o c e d u r e s e m p l o y e d by C o m i n c o L t d . we re ( S p e e r , 1 9 6 8 ) : N i t r o g e n - Co l eman N i t r o g e n A n a l y s e r w h i c h e m p l o y s t h e Dumas M e t h o d . C a l c i u m , M a g n e s i u m , - N i t r i c - p e r c h l o r i c a c i d o x i d a t i o n o f t h e and P o t a s s i u m t i s s u e s w i t h s u b s e q u e n t a n a l y s i s by a t o m i c a b s o r p t i o n u s i n g a J a r r e t t - A s h A t o m i c 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 . S u l p h u r - Wetr o x i d a t i o n by method o f Shaw ( 1 9 5 9 ) . S u b s e q u e n t t o t h i s wet a s h i n g p r o c e d u r e t h e s u l p h u r i s d e t e r m i n e d u s i n g a t u r b i -d i m e t r i c t e c h n i q u e e m p l o y i n g S u l f a v e r P o w d e r . ( S u l f a v e r i s a r e a g e n t s u p p l i e d by t h e Hoch C h e m i c a l Company , Ames , I o w a ) . P h o s p h o r u s - N i t r i c - p e r c h l o r i c a c i d o x i d a t i o n o f t h e t i s s u e s . P h o s p h o r u s on t h i s d i g e s t d e t e r -m i n e d by t h e me thod o f S h e l t o n and H a r p e r ( 1 9 4 1 ) . 27 i i i ) S t a t i s t i c a l t e c h n i q u e s S t r a t i f i e d random s a m p l i n g was u t i l i s e d i n a l l a s p e c t s o f t h i s s t u d y . S t r a t a were d e f i n e d f r o m a e r i a l p h o t o g r a p h s , l o c a l k n o w l e d g e , and s p e c i f i c a l l y s e l e c t e d b o u n d a r i e s . C o r r e l a t i o n , v a r i a n c e and m u l t i p l e l i n e a r and c u r v i l i n e a r r e g r e s s i o n a n a l y s e s were a p p l i e d where a p p r o p r i a t e f o l l o w i n g t h e p r i n c i p l e s g i v e n i n S t e e l and T o r r i e ( I 9 6 0 ) and L i ( 1 9 6 4 ) . C a l c u l a t i o n s were e f f e c t e d on an IBM 7044 c o m p u t e r w i t h p r o -grammes o f t h e F a c u l t y o f F o r e s t r y . The e l i m i n a t i o n p r o c e d u r e o f t h e m u l t i p l e r e g r e s s i o n p r o g r a m m e , b a s e d upon t h e ' t ' s t a -t i s t i c , has been d e s c r i b e d by Kozak and S m i t h ( 1 9 6 5 ) . E. A p p l i c a b i l i t y o f t h e r e s u l t s A l l a n a l y s e s , w i t h t h e e x c e p t i o n o f t h o s e f r o m C h a p t e r 8 , we re b a s e d upon d a t a c o l l e c t e d w i t h i n t h e V a n c o u v e r e n v i r o n s , and p r i m a r i l y f r o m t h e U . B . C . R e s e a r c h F o r e s t . Where d a t a f r o m o t h e r l o c a t i o n s were a v a i l a b l e c o m p a r i s o n s have been made . The r e s u l t s c o n t a i n e d h e r e a r e r e l e v a n t t o c o a s t a l w e s t e r n h e m l o c k s t a n d s b e t w e e n 500 and 1 , 5 0 0 f e e t a . s . l . , and i n g e o -g r a p h i c a l a r e a s w i t h a p p r o x i m a t e l y 100 i n c h e s o f r a i n f a l l p e r y e a r . Some o f t h e r e s u l t s do i n d i c a t e t h a t c e r t a i n s i t e c h a r a c t e r i s t i c s o f t h e U . B . C . R e s e a r c h F o r e s t a r e u n u s u a l . Thus f o l i a g e l e v e l s o f c a l c i u m a r e f a r h i g h e r t h a n t h o s e f o u n d i n o t h e r a r e a s o f B r i t i s h C o l u m b i a , and t h e s t a n d s c o n t a i n l a r g e p e r c e n t a g e s o f w e s t e r n r e d c e d a r . S e e d l i n g g r o w t h r a t e s c o n t a i n e d i n t h e s e r e s u l t s a r e f a s t e r t h a n t h o s e r e p o r t e d f r o m W a s h i n g t o n , U . S . A . 28 G r o w t h d a t a have been c o l l e c t e d o v e r t h e t w e n t y - y e a r p e r i o d f r o m 1947 t o 1966 and r e s u l t s o f f a c t o r s a c c o u n t i n g f o r v a r i a -t i o n i n g r o w t h a r e d i r e c t l y c o n c e r n e d w i t h t h i s g r o w t h p e r i o d o n l y . A b n o r m a l . y e a r s , l i k e 1 9 6 5 , when g r o w t h was s e v e r e l y c u r -t a i l e d , l i m i t t h e e x t r a p o l a t i o n o f t h e s e r e s u l t s t o o t h e r g r o w t h p e r i o d s . B e c a u s e t r e e s t a n d p a p u l a t i o n s v a r y i n s i z e , s t r u c t u r e , and c o m p o s i t i o n , and b e c a u s e g r o w t h v a r i e s w i t h c l i m a t i c c o n -d i t i o n s , s i t e , and s t a n d age t h e b a s i c s t a t i s t i c s o f most p o p u -l a t i o n s a n a l y s e d have been i n c l u d e d i n t h i s d i s s e r t a t i o n . F. C h a p t e r summary A l t h o u g h w e s t e r n h e m l o c k i s a d o m i n a n t s t a n d componen t o f much o f t h e c o a s t a l r e g i o n o f t h e P a c i f i c N o r t h w e s t , and o c -c u r s upon s i t e s s u i t a b l e f o r i n t e n s i v e o r f l e x i b l e management , i d e a l s y s t e m s o f s t a n d management a r e s t i l l u n c e r t a i n . In o r d e r t o m a n i p u l a t e s t a n d s t o f u l f i l l management o b j e c t i v e s t h e amount and c a u s e s o f n a t u r a l v a r i a t i o n i n t r e e and s t a n d g r o w t h must be a s c e r t a i n e d . Amongst t h e s e c a u s e s o f v a r i a t i o n t h e f a c t o r s o f s t o c k i n g and s t a n d d e n s i t y a r e v e r y i m p o r t a n t i n t h e i r e f f e c t s upon t r e e and s t a n d g r o w t h and y i e l d . D e t a i l e d t r e e g r o w t h d a t a were c o l l e c t e d f r o m t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a ( U . B . C . ) R e s e a r c h F o r e s t , H a n e y , B . C . A b r i e f d e s c r i p t i o n o f t h e s e d a t a , t h e i r me thods o f c o l -l e c t i o n and s u b s e q u e n t a n a l y s e s were g i v e n . 5 t a n d g r o w t h d a t a were s u p p l i e d by G o v e r n m e n t and p r i v a t e a g e n c i e s . M u l t i -p l e r e g r e s s i o n a n a l y s e s , and a n a l y s e s o f v a r i a n c e and c o v a r i -a n c e were u s e d t o d e t e r m i n e t h e s i z e o f , and r e l a t i v e 29 i m p o r t a n c e o f f a c t o r s a f f e c t i n g t h e g r o w t h and y i e l d o f t r e e s and s t a n d s . P a r t i c u l a r e m p h a s i s was p l a c e d upon t h e d e t e r m i n a -t i o n and i n t e r a c t i o n o f s e v e r a l e x p r e s s i o n s o f s t a n d d e n s i t y . A l i m i t e d s a m p l e o f b i o m a s s d a t a was c o l l e c t e d and f e r t i l i s a -t i o n a f f e c t s upon g r o w t h ' a n d f o l i a r n u t r i e n t c o n c e n t r a t i o n we re i n v e s t i g a t e d . A l t h o u g h d a t a were c o l l e c t e d f r o m one r e -s t r i c t e d g e o g r a p h i c a l l o c a t i o n f o r a s p e c i f i c t i m e p e r i o d t h e r e s u l t s c an be a p p l i e d t o t h e commonest w e s t e r n h e m l o c k s t a n d t y p e s f o u n d w i t h i n t h e c o a s t a l w e s t e r n h e m l o c k r e g i o n . R e s u l t s a r e n o t n e c e s s a r i l y a p p l i c a b l e i n d e t a i l o u t s i d e t h i s g e o g r a -p h i c a l a r e a . 30 2 . CHARACTER IST ICS OF COASTAL WE5T.ERN HEMLOCK A . D e s c r i p t i o n o f t h e s p e c i e s i ) D i s t r i b u t i o n and r a n g e o f c o a s t a l w e s t e r n h e m l o c k . The s p e c i e s has a n a t u r a l r a n g e f r o m t h e K e n a i p e n i n s u l a and P r i n c e W i l l i a m Sound i n A l a s k a (63°l\l) s o u t h w a r d s a l o n g t h e P a c i f i c c o a s t t o n o r t h w e s t e r n C a l i f o r n i a (38°l\l). I t o c c u r s on t h e i s l a n d s and s e a w a r d s l o p e s o f t h e c o a s t a l m o u n t a i n r a n g e s and p e n e t r a t e s i n l a n d a l o n g t h e r i v e r v a l l e y s t o e l e v a t i o n s o f 3 , 0 0 0 f e e t . W i t h i n t h i s s t u d y , o n l y t h e g r o w t h o f t h o s e s t a n d s on t h e c o a s t a l m o u n t a i n s t o a maximum e l e v a t i o n o f 3 , 0 0 0 f e e t has been c o n s i d e r e d . A v e r a g e a n n u a l p r e c i p i t a t i o n i n t h i s c o a s t a l r e g i o n r a n g e s f r o m 38 i n c h e s a t E u r e k a , C a l i f o r n i a , t o 150 i n c h e s i n A l a s k a ( B e r n s t e n , 1 9 5 8 ) , and f u r t h e r t o 260 i n c h e s a t u p p e r e l e v a t i o n s i n c o a s t a l B r i t i s h C o l u m b i a ( K r a j i n a , 1 9 6 5 ) . T t u r e r a n g e s f r o m o v e r 100 ° F down t o - 2 2 ° F . C l i m a t e o f t h e c o a s t a l r e g i o n i s s u p e r h u m i d ( B e r n s t e n , 1958 ) o r e q u a b l e m a r i n e humid ( K r a j i n a , 1 9 6 5 ) w i t h a Koppen c l a s s i f i c a t i o n o f C f b . W i t h i n t h i s r e g i o n t h e s p e c i e s o c c u r s on a w i d e v a r i e t y o f s o i l s b u t g rows b e s t on d e e p , w e l l - d r a i n e d s o i l s , i n c l u d i n g t h o s e w i t h a b u n d a n t o r g a n i c m a t t e r . S o i l r e a c t i o n u n d e r c o a s t a l w e s t e r n h e m l o c k s t a n d r a n g e s f r o m pH 3.5 t o 5 .0 ( B e r n s t e n , 1 9 5 8 ) , b u t v a l u e s i n t h e s u r f a c e h o r i z o n s down t o pH 2 .9 have been f o u n d by L e s k o ( 1 9 6 1 ) . The p r e v a i l i n g s o i l p r o c e s s u n d e r w e s -t e r n h e m l o c k s t a n d s i s p o d s o l i s a t i o n w i t h on a c c u m u l a t i o n o f 31 raw mor humus . S u b s e q u e n t n i t r i f i c a t i o n w i t h i n t h e s o i l ( m i n e r a l and o r g a n i c m a t t e r ) i s v i r t u a l l y z e r o ( G a r m , 1 9 5 8 ) , C o a s t a l w e s t e r n h e m l o c k i s an i m p o r t a n t componen t o f f o u r f o r e s t , t y p e s ( S e r n s t e n , 1958 ) and a d e t a i l e d e c o l o g i c a l c l a s s i f i c a t i o n o f a s s o c i a t e d p l a n t s was g i v e n by O r l o c i ( 1 9 6 1 , 1 9 6 4 ) and K r a j i n a ( 1 9 6 5 ) . Two s u b z o n e s were d i s t i n g u i s h e d by K r a j i n a ( 1 9 6 5 ) r d e l i m i t e d by t h e 1 0 0 - 1 1 0 i n c h i s o h y e t w h i c h c o r r e s p o n d s t o t h e 1 , 2 0 0 t o 1 , 3 0 0 f o o t c o n t o u r l e v e l i n s o u t h w e s t e r n B r i t i s h C o l u m b i a , W i t h i n t h e l o w e r d r y s u b z o n e t h e p r i n c i p a l v e g e t a t i o n i n d i c a t o r s a r e s a l a l , O regon g r a p e , P l a q i o t h e c i u m u n d u l a t u m . a n d s w o r d - f e r n , w h e r e a s w i t h i n t h e w ' e t t e r s u b z o n e t h e y i n c l u d e s a l a l , V a c c i n i u m , P l a q i o t h e c i u m u n d u l a t u m , B l e c h n u m . and s k u n k c a b b a g e . In t h e f l o o d - p l a i n a s s o c i a t i o n s - d e v i l 1 s c l u b i s a l s o an i n d i c a t o r a l o n g w i t h s a l m o n b e r r y . i i ) E c o l o g i c a l and s i l v i c a l c h a r a c t e r i s t j . e s I t i s a p p a r e n t f r o m t h e a b o v e n o t e s on d i s t r i b u t i o n t h a t w e s t e r n h e m l o c k o c c u r s o v e r a w i d e c l i m a t i c r a n g e , on a v a r i e t y o f s i t e s , and i s a componen t o f s e v e r a l p l a n t a s s o c i a t i o n s . Of p a r t i c u l a r p r a c t i c a l i m p o r t a n c e t o f o r e s t e r s i s t h e r e l a -t i v e g r o w t h r a t e and y i e l d upon e a c h o f t h e s e s i t e s , and how s u c c e s s f u l l y t h e l a t t e r c an be amended t o e n h a n c e s t a n d g r o w t h . The m a t u r e t r e e s o f t h i s s p e c i e s s e e d p r o l i f i c a l l y ( B e r n s t s n , 1 9 5 8 ) , and a l t h o u g h t h e r e was no r e c o g n i s a b l e p e r i o d i c i t y due t o g e n e r a l s i t e e f f e c t s , a t t a c k s by i n s e c t s and damage f r o m f i r e s t i m u l a t e d c o n e p r o d u c t i o n ( W a t s o n , 1 9 1 8 ) . T r e e s may b e a r c o n e s as e a r l y as age 1 5 , e s p e c i a l l y i n open 32 s t a n d s , b u t e c o n o m i c c o l l e c t i o n s c an be made f r o m age 30 o n -w a r d s ( M a c D o n a l d e_t a_ l . , 1 9 5 7 ) , and a r e e a s i e s t w i t h a n e t ( S e a l e t a l . , 1 9 6 5 ) . S eeds a r e l i g h t and w i l l be c a r r i e d by w i n d s up t o a m i l e . G e r m i n a t i o n p e r c e n t a g e v a r i e s w i t h t h e d i s t a n c e f r o m s e e d s o u r c e , month o f y e a r , and m a g n i t u d e o f s e e d - c r o p ( R u t h and B e r n s t e n , 1 9 5 5 ; H e t h e r i n g t o n , 1 9 6 1 a ) . S e e d - b e d t y p e and e v e n -n e s s and m i c r o s i t e a f f e c t r a t e and p e r c e n t a g e o f g e r m i n a t i o n . W e s t e r n h e m l o c k s e e d g e r m i n a t e a t l o w e r t e m p e r a t u r e s t h a n do s e e d s o f i t s a s s o c i a t e d s p e c i e s ( A n d e r s o n , 1 9 5 6 ) . G e r m i n a n t s p r e f e r ammonium t o n i t r a t e as a s o u r c e o f n i t r o g e n ( T a y l o r , 1 9 3 5 ; K r a j i n a , 1 9 5 9 ) , and need a r e g u l a r s u p p l y o f s o i l m o i s -t u r e ( R u t h , 1 9 6 8 ) . I t i s p r e f e r a b l e t h a t t h i s w a t e r i s d e r i v e d f r o m p r e c i p i t a t i o n u n l e s s s e e p a g e w a t e r i s b a s e u n s a t u r a t e d ( K r a j i n a , 1 9 5 4 ) . A c c o r d i n g t o D o y l e - D a v i d s o n ( 1959 ) and Wood ( 1 9 5 5 ) w e s t e r n h e m l o c k i s l e s s d e m a n d i n g o f s i t e q u a l i t y t h a n i s S i t k a s p r u c e . In i t s y o u t h w e s t e r n h e m l o c k b e n e f i t s f r o m s h e l t e r , and s e v e r e l y e x p o s e d t r e e s w i l l grow i n a s t u n t e d f o r m u n t i l c a n o -py c l o s e s ( Z e h e t m a y r , 1 9 5 4 ) . P a r t i a l s h a d i n g f o r t h e f i r s t t h r e e y e a r s i s t h o u g h t t o be b e n e f i c i a l ( H a n z l i k , 1928 ) b u t op t imum g r o w t h i s f o u n d i f f u l l t o p l i g h t i s g i v e n . H e i g h t g r o w t h o f y o u n g s e e d l i n g s i s r e p o r t e d t o be v e r y s l o w w i t h o n l y 8-12 i n c h e s a t t a i n e d w i t h i n t h r e e y e a r s ( B e r n s t e n , 1 9 5 8 ) . E f f e c t s o f s i t e q u a l i t y on young g r o w t h a r e c o m p l e x t h r o u g h t h e i n t e r a c t i o n o f v e g e t a t i o n , s o i l t y p e , and l o c a l c l i m a t i c c o n d i t i o n s . Bunce (1961 ) f o u n d c o n v e n t i o n a l s i t e i n d e x had no c o r r e l a t i o n w i t h s e e d l i n g g r o w t h r a t e , b u t a c o r r e l a t i o n was 33 f o u n d by W a l t e r s e_t a l _ . , ( 1 9 6 1 ) . E f f e c t s o f v e g e t a t i o n a r e t h r e e f o l d . S i t e s o f h i g h q u a l i t y a r e c h a r a c t e r i s e d by v e g e t a -t i o n w h i c h i n c l u d e s n i t r o p h i l o u s p l a n t s (Ga rm, 1 9 5 8 ) and w e s t e r n h e m l o c k s e e d l i n g s a r e l a s s v i g o r o u s i n m u l l humus ( K r a j i n a , 1 9 5 9 ) . A s e c o n d d e t r i m e n t a l f a c t o r on h i g h q u a l i t y s i t e s i s t h e l u x u r i a n c e o f t h e v e g e t a t i o n and i t s d e s s i c a t i n g e f f e c t s i n t h e summer ( N e w t o n , 1 9 6 4 ) . W e s t e r n h e m l o c k s e e d l i n g s a r e v e r y s u s c e p t i b l e t o summer d r o u g h t . In c o n t r a s t , t h e l u x -u r i a n c e o f v e g e t a t i o n on t h e h i g h q u a l i t y s i t e s , and t h e g r e a t -e r a b u n d a n c e o f r o t t e n w o o d , p r o v i d e s more s i d e s h a d e w h i c h i n c r e a s e s s u r v i v a l . The h y g r o t y p e d e f i n i t e l y becomes more m e s i c w i t h i n c r e a s e d s i t e q u a l i t y ( Q r l o c i i n K r a j i n a , 1 9 6 5 ) . P r e v i o u s t r e a t m e n t i s a l s o i m p o r t a n t t o e a r l y g r o w t h o f w e s t e r n h e m l o c k . C o m p a c t i o n and t h e r e m o v a l o f s u r f a c e o r g a n i c m a t t e r r e s u l t e d i n i n c r e a s e d m o r t a l i t y o f p l a n t e d t r e e s ( W a l t e r s , 1 9 6 4 ) . S u p p r e s s i o n o f w e s t e r n h e m l o c k g r o w t h t h r o u g h i n s u f f i c i e n t l i g h t i s r a p i d l y o v e r c o m e when c o n d i t i o n s i m p r o v e ( M a c D o n a l d e t a l . , 1 9 5 7 ) . The s p e c i e s i s c l a s s i f i e d as " v e r y s h a d e t o l e r -a n t " (Tourney and K o r s t i a n , 1 9 4 7 ) , and a l t h o u g h g r o w t h i s n o t op t imum u n d e r s h a d e t h e t r e e w i l l c o n t i n u e t o l i v e and grow a t a m o d e r a t e r a t e (Watson and B i l l i n g s l e a , 1 9 1 4 ) . D u r i n g i t s j u v e n i l e g r o w t h s t a g e s (a'ges 10 t o 30 y e a r s ) t h i s s p e c i e s i s v e r y f l e x i b l e , and r e s p o n d s w e l l t o s t e m d e n s i t y m a n i p u l a t i o n s ( M a l m b e r g , 1 9 6 5 ) . Once e s t a b l i s h e d t h e t r e e g rows f a s t and s t a n d s can a t t a i n v e r y h i g h p r o d u c t i v i t y ( H i l e y , 1 9 5 0 ; D imock I I , 1 9 5 8 ) . I t commonly o c c u r s i n m i x e d s t a n d s and l e n d s i t s e l f t o m i x e d s t a n d 34 management ( E l m h i r s t , 1 9 5 0 ; Wood, 1955 ) . The d i v e r s e e c o l o -g i c a l a s s o c i a t i o n s o f t h i s s p e c i e s , t o g e t h e r w i t h i t s l owr :•: demands on s i t e q u a l i t y and i t s a b i l i t y t o t o l e r a t e s h a d e , r e s u l t i n i t s s u i t a b i l i t y f o r many f o r m s o f management as s u g g e s t e d by A l l e n ( 1 9 0 2 ) . B e i n g s h a l l o w - r o o t e d , and s e n s i t i v e t o e x p o s u r e , i t b e n e f i t s f r o m m i x t u r e s w i t h S i t k a s p r u c e o r D o u g l a s f i r ( K r a j i n a , 1 9 5 4 ; A n d e r s o n , 1 9 5 6 ) . I n c r e a s e s i n t h e s i t e i n d e x and p r o d u c t i v i t y o f D o u g l a s f i r , as t y p i f i e d by p l a n t a s s o c i a t i o n s , a r e p a r a l l e l e d by i n -c r e a s e s i n p r o d u c t i v i t y o f w e s t e r n h e m l o c k on t h e same s i t e ( E i s , 1 9 6 2 ) . A l t h o u g h t h e s e two s p e c i e s have d i f f e r e n t o p -t imum r e q u i r e m e n t s f a r g r o w t h t h e p r o d u c t i v i t y o f w e s t e r n h e m l o c k does i n c r e a s e w i t h d e c r e a s e d s o i l a c i d i t y and i s o p -t imum on s i t e s whe re n i t r o p h i l o u s s p e c i e s a r e r e c o r d e d ( Q r l o c i i n K r a j i n a , 1 9 6 5 ) . P r o d u c t i v i t y was f o u n d t o be h i g h e r i n t h e d r y s u b z o n e by E i s ( 1 9 6 2 ) , and t h e r e t h e t r e e s may o b t a i n t h e i r w a t e r a t c o n s i d e r a b l e d e p t h b u t t h e s u r f a c e v e g e t a t i o n t y p i f i e s r e l a t i v e l y d r y s u r f a c e c o n d i t i o n s . U s i n g s o i l m o i s -t u r e r e g i m e , t h i c k n e s s o f humus l a y e r , and p l a n t c o m m u n i t y E i s ( 1962 ) f o u n d he c o u l d a c c o u n t f o r 58 p e r c e n t o f t h e v a r i -a b i l i t y i n t h e d e p e n d e n t s i t e i n d e x . Unde r d e n s e s t a n d s , c r o w n s a r e n a r r o w and t e n d t o be s h o r t , b u t g i v e n u n r e s t r i c t e d g r o w i n g s p a c e b r a n c h e s p e r s i s t , . and s t e m f l u t i n g s o m e t i m e s o c c u r s ( A l l e n , 1 9 0 2 ; M a c D o n a l d c t a l . , 1 9 5 7 ; B e r n s t e n , 1 9 5 8 ) . S u p e r - a b u n d a n t r e g e n e r a t i o n r e -s u l t s i n d e n s e s t a n d s i n w h i c h g r o w t h may s t a g n a t e . U n d e r t h e s e c o n d i t i o n s s t a n d s a r e s o m e t i m e s s n o w - b r o k e n (Wood, 1 9 5 5 ) , 35 b u t s t a g n a t i o n i s n o t common i n c o a s t a l w e s t e r n h e m l o c k . A more d e t a i l e d a c c o u n t o f s i l v i c a l c h a r a c t e r i s t i c s w i t h r e s p e c t t o p a t h o l o g y i s g i v e n b e l o w . i i i ) P a t h o l o g y In i t s y o u t h w e s t e r n h e m l o c k c a n n o t w i t h s t a n d e x p o s u r e ( Z e h e t m a y r , 1 9 5 4 ; Edwa rds e_t a l . , 1 9 6 1 ) , and u n d e r s e v e r e c o n -d i t i o n s i t w i l l become s c o r c h e d ( K e l l e r , 1 9 6 8 ) and f i n a l l y d e f o l i a t e d ( M a c D o n a l d e_b a l . , 1 9 5 7 ) . Snow damage i s r a r e ( C . B . W i l l i a m s , 1966 ) e x c e p t i n v e r y d e n s e s t a n d s ( O s b o r n , 1 9 6 7 c ) , and i t e x h i b i t s v a r y i n g s u s c e p t i b i l i t y t o s p r i n g f r o s t s ( H u n t e r B l a i r , 1 9 4 6 ; Day and P e a c e , 1 9 4 6 ; Edwa rds e t a l . , 1 9 6 3 ) . M a l m b e r g ( 1965 ) f o u n d t h a t s t a n d s up t o 100 f e e t t a l l w i t h -s t o o d t h e d e s t r u c t i v e w i n d s t o r m o f O c t o b e r , 1962 i n t h e P a c i f i c N o r t h w e s t . T h i s a p p l i e d t o b o t h t h i n n e d and u n t h i n n e d s t a n d s . B e c a u s e many t r e e s o r i g i n a t e upon l o g s o r s t u m p s t h i s s p e c i e s i s o f t e n v e r y s u s c e p t i b l e t o w i n d - b l o w ( O s b o r n , 1 9 6 7 c ) . M i x e d s t a n d s o f S i t k a s p r u c e and w e s t e r n h e m l o c k i n t h e C a s c a d e Head E x p e r i m e n t a l F o r e s t ( O r e g o n ) aged 90 - t o 1 0 0 - y e a r s s u f f e r e d f r o m w i n d - b l o w when any c u t t i n g was made - even when i t was f o r a n a r r o w r o a d (McComb and M u n g e r , 1 9 4 0 ; M u n g e r , 1 9 4 6 ) . I t was c o n c l u d e d by R u t h and Y o d c r ( 1 9 5 3 ) t h a t w e s t e r n h e m l o c k was l e s s w i n d f i r m t h a n S i t k a s p r u c e o r D o u g l a s f i r . L a r g e t r e e s (more t h a n 30 i n c h e s d . b . h . ) , and t h o s e i n f e c t e d w i t h r o o t r o t s were p a r t i c u l a r l y s u s c e p t i b l e . Damage f r o m w i n d was most s e v e r e i n p l o t s aged 6 1 - 8 0 y e a r s a c c o r d i n g t o W i l e y ( 1 9 6 5 ) . D o m i n a n t and c o d o m i n a n t t r e e s c o m p r i s e d 42 p e r c e n t 36 o f t h e number o f t r e e s l o s t b u t 83 p e r c e n t o f t h e b a s a l a r e a . Of t h e t r e e s damaged , 40 p e r c e n t (by b a s a l a r e a ) had r o o t o r s t e m r o t . W i l e y c o n c l u d e d t h a t damaged o r weakened t r e e s were t h e p r i m e t a r g e t . W e s t e r n h e m l o c k i s p a r a s i t i s e d by d w a r f m i s t l e t o e t h r o u g h -o u t i t s c o m m e r c i a l r a n g e ( G i l l and H a w k s w o r t h , 1 9 6 1 ) . As i t i s p r i m a r i l y s p r e a d by e x p l o s i v e f r u i t s r a t h e r t h a n by a n i m a l s s t a n d s c an be managed t o e r a d i c a t e t h e damaged t r e e s w i t h l i t -t l e d a n g e r o f s u b s e q u e n t r e - i n f e c t i o n . S e v e r e i n f e c t i o n s o f m i s t l e t o e r e d u c e wood d e n s i t y and l u m b e r y i e l d ( W e l l w o o d , 1 9 5 6 ) . F u r t h e r m o r e , t h e m i s t l e t o e p r o v i d e s an e n t r a n c e f o r f u n g i and c a u s e s r e d u c e d t r e e v i g o u r ( B u c k l a n d and M a r p l e s , 1 9 5 2 a ) . C l e a r - c u t t i n g and r e m o v i n g a l l i n f e c t e d t r e e s i s t h e r e c o m m e n -ded management p r a c t i c e . U n l e s s a l l i n f e c t e d t r e e s a r e r emoved no f o r m o f s h e l t e r w o o d s y s t e m can be u s e d as r e g e n e r a t i o n w i l l be a t t a c k e d . L i t t l e damage i s done t o w e s t e r n h e m l o c k by mammals , a l -t h o u g h s e e d s and s e e d l i n g s have been a t t a c k e d i n O r e g o n by d e e r - m i c e and r a b b i t s r e s p e c t i v e l y ( O s b o r n , 1 9 6 7 c ) . I s a a c ( 1933 ) recommended b r o a d c a s t s p r e a d i n g o f w e s t e r n h e m l o c k and S i t k a s p r u c e s e e d as i t was l e s s l i k e l y t o be e a t e n by r o d e n t s t h a n t h e l a r g e r s e e d s o f D o u g l a s f i r . T h i s was c o n f i r m e d i n s t u d i e s r e p o r t e d by G a s h w i l e r ( 1967 ) f r o m t h e C a s c a d e s . The o n l y s e r i o u s mammal ian a t t a c k r e p o r t e d i n B r i t i s h C o l u m b i a was by s q u i r r e l s on T u r n o u r I s l a n d ( B u c k l a n d , 1 9 5 2 , B u c k l a n d and M a r p l e s , 1 9 5 2 b ) . I t was t h o u g h t t h a t t h e a n i m a l s a t e t h e i n n e r b a r k w h i c h c o n t a i n e d a h i g h l e v e l o f g l u c o s e . C o n t r o l 37 was e a s i l y a c h i e v e d by b a i t i n g and p o i s o n i n g as t h e s e a p r e -v e n t e d e a s y r e - i n v a s i o n . Some s e v e r e v o l e damage has been r e p o r t e d f r o m G r e a t B r i t a i n ( Edwa rds et. a l , . , 1 9 6 1 ) . S c a t t e r e d c l u m p s o f m a t u r e t r e e s have been a t t a c k e d by t h e r e d - b r e a s t e d s a p s u c k e r i n B r i t i s h C o l u m b i a ( Z i l l e r and S t i r l i n g , 1 9 6 1 ) . F r e e z i n g , w i n d - b l o w , m i s t l e t o e i n f e c t i o n , a n i m a l damage , d e f o l i a t i o n , l o g g i n g damage , and n a t u r a l b a r k i n g a l l i n c r e a s e t h e s u s c e p t i b i l i t y o f w e s t e r n h e m l o c k t o f u n g a l a t t a c k . Decay c a u s e d by P o l y p o r u s a b i e t i n u s r e d u c e d s a w l o g and p u l p l o g q u a l i t y i n s t a n d s a f f e c t e d by t h e s e v e r e f r e e z e o f 1955 ( Shea and W o t t e n , 1 9 6 1 ) . F u n g a l a t t a c k does n o t a l w a y s f o l l o w cam-b i a l i n j u r y f r o m f r e e z i n g , as n o t e d by R u s s e l l ( 1 9 6 5 ) . W i n d - b l o w n wea/tern h e m l o c k t r e e s d e c a y e d v e r y q u i c k l y u n d e r c o a s t a l c o n d i t i o n s and w i t h i n e i g h t y e a r s even t h e l a r -g e s t t r e e s we re c o m p l e t e l y u n m e r c h a n t a b l e ( B u c h a n a n and E n g l e r t h , 1 9 4 0 ) . Sapwood i n w e s t e r n h e m l o c k i s d e f i n i t e l y n o t r e s i s t a n t t o d e c a y ( S h e a , 1 9 6 0 ) . B u c k l a n d and M a r p l e s ( 1952b ) f o u n d t h a t a l l t h e t r e e s w h i c h had been more t h a n 25 p e r c e n t g i r d l e d (by s q u i r r e l s ) c o n t a i n e d d e c a y . D e f o l i a t e d t r e e s a r e a l s o r a p i d l y a t t a c k e d by w o o d - r o t t i n g f u n g i ( E n g l e h a r d t , 1 9 5 7 ) . The t h i n b a r k o f w e s t e r n h e m l o c k t r e e s , S m i t h and Kozak ( 1 9 6 7 ) i s n o t v e r y e f f e c t i v e i n p r o t e c t i n g t h e u n d e r l y i n g w o o d . Wood r o t t i n g f u n g i e n t e r t h r o u g h b r o k e n t o p s , s u n s c a l d a r e a s , s t e m and r o o t i n j u r i e s . A l t h o u g h Fomes p i n i c a u s e d t h e h i g h e s t number o f i n f e c t i o n s t h e g r e a t e s t v o l u m e l o s s was due ^ ° Fomes a n n o s u s i n E n g l e r t h ' s ( 1942 ) s t u d y . A p p r o x i m a t e l y 27 p e r c e n t o f t h e d e c a y was c a u s e d by e n t r y t h r o u g h m i s t l e t o e 38 i n f e c t i o n s . The y o u n g e s t i n f e c t e d t r e e f o u n d by E n g l e r t h was 63 y e a r s o l d . A s s o c i a t i o n s of i n f e c t i o n s o f w o o d - r o t t i n g f u n g i and m i s t l e t o e were a l s o f o u n d by F o s t e r and F o s t e r ( 1 9 5 1 ) . They f o u n d t h a t t h e most s e r i o u s w o o d - r o t t i n g f u n g u s was Fomes  p i n i c o l a i n h e m l o c k s on t h e Queen C h a r l o t t e I s l a n d s , B . C . S i m i l a r r e s u l t s were r e p o r t e d by B u c k l a n d _et _al_. ( 1949 ) f o r h e m l o c k s f r o m t h e F r a n k l i n r i v e r a r e a on V a n c o u v e r I s l a n d , B . C . F u n g a l e n t r a n c e was m o s t l y t h r o u g h s t em s c a r s w i t h r o o t i n f e c t i o n s s e c o n d i n i m p o r t a n c e . F o s t e r and F o s t e r ( 1953 ) s t u d i e d t h e u n d e r s t o r e y t r e e s (up t o 15 i n c h e s d . b . h . ) and f o u n d n e g l i g i b l e h e a r t r o t l o s s e s , and a s u b s t a n t i a l v o l ume o f p u l p w o o d . 5 t u d i e s f r o m t h e U n i t e d S t a t e s have i n d i c a t e d t h a t Fomes a n n o s u s i s t h e d o m i n a n t w o o d - r o t t i n g f u n g u s i n c o a s t a l w e s t e r n h e m l o c k t r e e s ( E n g l e r t h and I s a a c , 1 9 4 5 ; Rhoads and W r i g h t , 1 9 4 6 ; W r i g h t e t a l . , 1 9 4 7 ; W r i g h t and I s a a c , 1 9 5 6 , Hunt and K r u e g e r , 1 9 6 2 ) . W e s t e r n h e m l o c k i s more 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 t h a n i s D o u g l a s f i r ( W o r t h i n g t o n , 1 9 6 1 ) . As d e c a y d e v e l o p s q u i c k l y a management r e g i m e i n v o l v i n g f r e q u e n t c u t t i n g was n o t a d v i s e d by Shea ( I 9 6 0 ) . Use o f w e s t e r n h e m l o c k as an a l t e r n a t e t r e e t o D o u g l a s f i r i n f e c t e d w i t h y e l l o w l a m i n a t e d r o o t r o t ( P o r i a w e i r i i ) was n o t c o n s i d e r e d p r a c t i c a l by B u c k l a n d _et a_l . , ( 1 9 5 6 ) . T h i s f u n g u s a t t a c k s a l l t r e e s , w h e t h e r v i g o r o u s o r n o t , and w e s t e r n h e m l o c k i s as s u s c e p t i b l e as D o u g l a s f i r . W a l l i s ( 1968 ) v e r i f i e d t h e r e s u l t s a b o v e , and r e p o r t e d t h a t P o r i a w e i r i i a t t a c k s a l l c r o w n c l a s s e s , on a l l s i t e s , and b o t h D o u g l a s f i r and w e s t e r n h e m l o c k w i t h i n d i f f e r e n c e . W e s t e r n h e m l o c k i n 39 B . C . i s s u s c e p t i b l e t o a t t a c k by Fomes a n n o s u s , w h i c h i s i t s most i m p o r t a n t f u n g a l p a t h o g e n , and i t a p p e a r s t o d a t e t h a t a l l c r o w n c l a s s e s a r e e q u a l l y i n f e c t e d . When p l a n t e d on a l r e a d y i n f e c t e d s i t e s w e s t e r n h e m l o c k i s one o f the- l e a s t r e s i s t a n t s p e c i e s , and f i r s t t h i n n i n g s i n G r e a t B r i t a i n (age 20 t o 30) may show up t o 50 p e r c e n t c r o p i n f e c t i o n (G l adman and G r e i g , 1 9 6 5 ) . W i t h i n t h e wes t s i d e s u b r e g i o n o f t h e U n i t e d S t a t e s a r e a s o f t h e P a c i f i c N o r t h w e s t w e s t e r n h e m l o c k v o l u m e l o s s e s a r e p r i m a r i -l y c a u s e d by h e a r t r o t s and d w a r f m i s t l e t o e ( C h i l d s and S h e a , 1 9 6 7 ) . The l a t t e r w i l l be e f f e c t i v e l y c o n t r o l l e d i n t h e f u t u r e by l o g g i n g and t h i n n i n g p r a c t i c e s , b u t t h i s may i n c r e a s e r o o t r o t damage . A me