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UBC Theses and Dissertations

Functional relationships between salal understory and forest overstory Vales, David Joseph 1985

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FUNCTIONAL RELATIONSHIPS BETWEEN SALAL UNDERSTORY AND FOREST OVERSTORY By DAVID JOSEPH VALES B . S c , Iowa S t a t e U n i v e r s i t y , 1981 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES ( F a c u l t y o f F o r e s t r y ) We 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 UNIVERSITY OF BRITISH COLUMBIA O c t o b e r 1986 © D a v i d J o s e p h V a l e s , 1986 9 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date H. /O DE-6(3/81) ABSTRACT Abundance of s a l a l (Gaultheria shall on P u r s h ) and i t s r e l a t i o n s h i p t o f o r e s t o v e r s t o r y were s t u d i e d i n immature f o r e s t s t a n d s on V a n c o u v e r I s l a n d h a v i n g some t o p o g r a p h i c a l c h a r a c t e r i s t i c s of d e e r w i n t e r r a n g e s . P l o t s s a m p l e d o v e r a ra n g e of s t o c k i n g l e v e l s i n d i c a t e d t h a t s a l a l d e n s i t y was s t r o n g l y r e l a t e d t o s i n g l e f o r e s t s t a n d c h a r a c t e r i s t i c s O z 0.92-0.94) b u t p r e d i c t i v e e q u a t i o n s d i f f e r e d between p l a n t a s s o c i a t i o n s . Most e q u a t i o n s p r e d i c t i n g s a l a l b i o m a s s or c o v e r d i d n o t d i f f e r between p l a n t a s s o c i a t i o n s . E q u a t i o n s c a l c u l a t e d f r o m d a t a f r o m s i n g l e s t a n d s a c c o u n t e d f o r more o t h e v a r i a t i o n i n s a l a l a bundance (r2 = 0.73-0.97) t h a n e q u a t i o n s d e v e l o p e d f r o m d a t a f r o m s e v e r a l s t a n d s ( r 2 = 0.39-0.92). Mean s a l a l s h o o t h e i g h t was g r e a t e s t u nder o v e r s t o r y c o v e r of 65 t o 80%. T r a n s m i s s i o n of g l o b a l , d i r e c t , d i f f u s e , a nd d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e s o l a r r a d i a t i o n t h r o u g h f o r e s t c a n o p i e s was s t u d i e d on 12 p l o t s d u r i n g sunny d a y s i n summer The p r o p o r t i o n s o f r a d i a t i o n t r a n s m i t t e d were a f u n c t i o n o f f o r e s t s t a n d c h a r a c t e r i s t i c s and d i f f e r e d among r a d i a t i o n c o m ponents. The r e l a t i o n s h i p between t h e p r o p o r t i o n o f d i f f u s e r a d i a t i o n t r a n s m i t t e d and s t a n d c h a r a c t e r i s t i c s d i f f e r e d among s t a n d s t r u c t u r e s . When d i r e c t beam r a d i a t i o n was s c a t t e r e d by open crowns o f s h o r t t r e e s and crowns e x t e n d e d below t h e h e i g h t o f r a d i a t i o n s e n s o r s , d i f f u s e r a d i a t i o n below t h e c a n o p y was h i g h e r t h a n o u t s i d e . The e x t e n t t o w h i c h d i f f e r e n t f o r e s t s t a n d c h a r a c t e r i s t i c s p r e d i c t t r a n s m i s s i o n and f o l l o w B e e r ' s law were e x p l o r e d . Sum of t r e e d i a m e t e r s and R e i n e k e ' s s t a n d d e n s i t y i n d e x p r e d i c t t r a n s m i s s i o n o f g l o b a l ( i 2 = 0.80-0.95) and d i r e c t r a d i a t i o n ( i 2 = 0.70-0.98) b e s t . O v e r s t o r y c o v e r p r e d i c t s t r a n s m i s s i o n of d i f f u s e r a d i a t i o n b e s t ( i 2 = 0.74) when t h e r e i s e x t e n s i v e i n t e r - p l o t v a r i a t i o n and b a s e s o f t r e e crowns a r e above s e n s o r s . F o r e s t s t a n d c h a r a c t e r i s t i c s o b t a i n e d by d i f f e r e n t s a m p l i n g methods gave d i f f e r e n t p r e d i c t a b i l i t i e s o f t h e components t r a n s m i t t e d . D i f f e r e n c e s were f o u n d between h e m i s p h e r i c a l p h o t o g r a p h e s t i m a t e s o f d i f f u s e r a d i a t i o n t r a n s m i t t e d and m e a s u r e d t r a n s m i s s i o n o f d i f f u s e and d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n . P h o t o g r a p h i c e s t i m a t e s o f d i r e c t r a d i a t i o n t r a n s m i t t e d d i f f e r e d f r o m m e a s u r e d t r a n s m i s s i o n o f d i r e c t r a d i a t i o n . The r e l a t i o n s h i p s o f s a l a l c h a r a c t e r i s t i c s t o t r a n s m i s s i o n o f s o l a r r a d i a t i o n components were e x a m i n e d . S a l a l d e n s i t y , b a s a l a r e a , f o l i a r p r o d u c t i v i t y , b i o m a s s , and c o v e r a l l i n c r e a s e d a s y m p t o t i c a l l y w i t h i n c r e a s i n g t r a n s m i s s i o n . The g r o w t h o f - s a l a l was more c l o s e l y r e l a t e d t o t r a n s m i s s i o n o f d i r e c t r a d i a t i o n {i2 = 0.65-0.99) t h a n t o g l o b a l , d i f f u s e , o r d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n . The r a t e a t w h i c h s a l a l abundance p l a t e a u e d was f a s t e s t f o r t r a n s m i s s i o n o f d i r e c t r a d i a t i o n . S a l a l s h o o t h e i g h t and b a s a l d i a m e t e r were l a r g e s t f o r low t o m o d e r a t e p r o p o r t i o n s o f r a d i a t i o n t r a n s m i t t e d . The l o w e s t and g r e a t e s t p r o p o r t i o n s t r a n s m i t t e d seemed t o a d v e r s e l y a f f e c t s a l a l s h o o t h e i g h t and d i a m e t e r . Shoot p r o d u c t i v i t y i n c r e a s e d a s y m p t o t i c a l l y w i t h i n c r e a s e d t r a n s m i s s i o n . S a l a l maximum abundance and s h o o t s i z e a r e r e g u l a t e d by t h e amount o f d i r e c t s o l a r r a d i a t i o n r e c e i v e d a t a s i t e and p r o b a b l y by an i n t e r a c t i o n w i t h a s i t e ' s m o i s t u r e r e g i m e . i v TABLE OF CONTENTS ABSTRACT i i TABLE OF CONTENTS v LIST OF TABLES v i i i LIST OF FIGURES X LIST OF APPENDICES x i i i ACKNOWLEDGMENTS x v i CHAPTER 1. GENERAL INTRODUCTION 1 REFERENCES 3 CHAPTER 2. RELATIONSHIPS BETWEEN SALAL UNDERSTORY AND FOREST OVERSTORY 4 INTRODUCTION 4 STUDY AREAS 6 METHODS 10 Understory 10 Over s t o r y 12 D e f i n i t i o n of v a r i a b l e s 13 Analyses 13 RESULTS 16 Regressions p r e d i c t i n g s a l a l abundances 16 Form of r e l a t i o n s h i p s 19 D i f f e r e n c e s among r e l a t i o n s h i p s 20 R e l a t i v e p r e d i c t a b i l i t y among independent v a r i a b l e s ....23 S a l a l shoot height 29 DISCUSSION 32 CONCLUSION 40 v REFERENCES 41 CHAPTER 3. RELATIONSHIPS EETWEEN TRANSMISSION OF SOLAR RADIATION AND FOREST STAND CHARACTERISTICS 45 INTRODUCTION 45 STUDY AREAS 47 METHODS 49 O v e r s t o r y s a m p l i n g 49 S o l a r r a d i a t i o n s a m p l i n g 50 D e f i n i t i o n o f v a r i a b l e s 52 A n a l y s e s 53 RESULTS AND DISCUSSION 55 P r o p o r t i o n s t r a n s m i t t e d 55 R a d i a t i o n - f o r e s t s t a n d r e l a t i o n s h i p s 59 E q u a t i o n d i f f e r e n c e s 67 S i t e f a c t o r s 67 G e n e r a l i t y o f e q u a t i o n s 71 CONCLUSION 76 REFERENCES 78 CHAPTER 4. RELATIONSHIPS OF SALAL (GAULTHERIA SHALLON) TO TRANSMISSION OF SOLAR RADIATION THROUGH FOREST CANOPIES 83 INTRODUCTION 83 STUDY AREAS 86 METHODS 89 RESULTS 92 Form o f r e s p o n s e 94 S a l a l s h o o t s i z e 99 v i Subzone d i f f e r e n c e s 102 R e l a t i v e p r e d i c t a b i l i t y among r a d i a t i o n components ....104 E f f e c t s of r a d i a t i o n components on s a l a l 105 DISCUSSION 106 CONCLUSION 112 REFERENCES 113 CHAPTER 5. MANAGEMENT IMPLICATIONS 117 INTRODUCTION 117 FOREST MANAGEMENT IMPLICATIONS 118 WILDLIFE MANAGEMENT IMPLICATIONS 123 REFERENCES 129 APPENDICES 133 v i i L I S T OF TABLES 2.1 D e s c r i p t i o n s of p l o t s u s e d t o sample s a l a l and f o r e s t s t a n d c h a r a c t e r i s t i c s 9 2.2 S i m p l e l i n e a r r e g r e s s i o n e q u a t i o n s o f s a l a l v a r i a b l e s a s a f u n c t i o n o f MCC, p l o t , and p r i s m v a r i a b l e s . Sample s i z e s : CWHa=lO, CWHb^S, CWHb 3 = 7. E q u a t i o n s s i g n i f i c a n t a t p < 0.05. R e g r e s s i o n e q u a t i o n : Y = b0 + fc,X 17 2.3 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 o f s a l a l v a r i a b l e s a s a f u n c t i o n o f MCC, p l o t , and p r i s m v a r i a b l e s . E q u a t i o n s s i g n i f i c a n t a t p r< 0.05. Sample s i z e s : CWHa=lO, CWHb,=5, CWHb 3=7 18 3.1 D e s c r i p t i o n s of p l o t s u s e d t o sample s o l a r r a d i a t i o n and f o r e s t s t a n d c h a r a c t e r i s t i c s . . . 48 3.2 D a i l y sums o f s o l a r r a d i a t i o n components by p l o t 56 3.3 R e g r e s s i o n c o e f f i c i e n t s o f e q u a t i o n s p r e d i c t i n g s o l a r r a d i a t i o n components f r o m f o r e s t s t a n d c h a r a c t e r i s t i c s . Sample s i z e s : CWHa=6, CWHb=6. E q u a t i o n s s i g n i f i c a n t a t p £ 0.05. R e g r e s s i o n e q u a t i o n : Y = ae 60 3.4 I n d i c e s o f d e t e r m i n a t i o n ( i 2 ) from r e g r e s s i o n s p r e d i c t i n g r a d i a t i o n components from f o r e s t s t a n d c h a r a c t e r i s t i c s u s i n g t h e r e g r e s s i o n f o r m Y = e 63 v i i i 3.5 C o m p a r i s o n o f d i f f u s e and d i r e c t s i t e f a c t o r s o b t a i n e d f r o m h e m i s p h e r i c a l p h o t o g r a p h s t o measured p r o p o r t i o n s o f s o l a r r a d i a t i o n components t r a n s m i t t e d 68 4.1 D e s c r i p t i o n s o f p l o t s u s e d t o sample s a l a l and s o l a r r a d i a t i o n 88 4.2 P l o t means a n d 95% c o n f i d e n c e i n t e r v a l s f o r s a l a l c h a r a c t e r i s t i c s 93 4.3 Below-canopy s o l a r r a d i a t i o n s t a t i s t i c s 94 4.4 R e g r e s s i o n c o e f f i c i e n t s of e q u a t i o n s p r e d i c t i n g s a l a l v a r i a b l e s f r o m s o l a r r a d i a t i o n c omponents. Sample s i z e s : CWHa=6, CWHb=6. E q u a t i o n s s i g n i f i c a n t at p < 0.06. R e g r e s s i o n e q u a t i o n : Y = ( a ( X - c ) ) / ( 1 + a(X-c)/b) .....95 5.1 T r e e d e n s i t i e s needed t o m a i n t a i n a c o n s t a n t s t a n d d e n s i t y i n d e x a s a v e r a g e d i a m e t e r c h a n g e s 120 i x L I S T OF FIGURES 2.1 P l o t l o c a t i o n s on V a n c o u v e r I s l a n d and a t t h e U.B.C. R e s e a r c h F o r e s t 7 2.2 The r e l a t i o n s h i p of s a l a l d e n s i t y - i r r 2 and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . Lower e q u a t i o n i s f o r CWHa and CWHb, combined d a t a ( • ), upper e q u a t i o n CWHb 3 (ffl) 24 2.3 The r e l a t i o n s h i p o f f o l i a r p r o d u c t i v i t y ( g - n r 2 ; CAGBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa ( • ) , CWHb, ( A ) , CWHb 3 (ffl). E q u a t i o n i s f o r combined d a t a 25 2.4 The r e l a t i o n s h i p of s a l a l f o l i a r b i o m a s s ( g - n r 2 ; FOLBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa (•), CWHb, ( A ) , CWHb 3 (ffl). E q u a t i o n r e p r e s e n t s combined d a t a 26 2.5 The r e l a t i o n s h i p o f s a l a l t o t a l b i o m a s s ( g - n r 2 ; TOTBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa (•), CWHb, ( A ) , CWHb 3 ( f f l ) . E q u a t i o n r e p r e s e n t s c o m b i n e d d a t a 27 2.6 The r e l a t i o n s h i p o f p e r c e n t c o v e r of s a l a l and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa ( • ) , CWHb, ( A ) , CWHb 3 (ffl). E q u a t i o n r e p r e s e n t s c o m b i n e d d a t a 28 x 2 .7 The r e l a t i o n s h i p o f a v e r a g e h e i g h t of s a l a l and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s (a) r e p o s e , (b) s t r e t c h . CWHa ( • ) , CWHb, ( A ) , CWHb 3 (ffi) 30 3.1 S o l a r i r r a d i a n c e a s a f u n c t i o n o f t i m e f o r p l o t 2 7 . Open g l o b a l (•) and d i f f u s e ( • • • • • • • ) , canopy g l o b a l (o) and d i f f u s e (•) 59 3 . 2 R e l a t i o n s h i p s between t h e p r o p o r t i o n s of s o l a r r a d i a t i o n components t r a n s m i t t e d and mean crown c o m p l e t e n e s s . D o t t e d l i n e s i n a, b, and d a r e r e l a t i o n s h i p s f o r i n d i v i d u a l s u b z o n e s . Dashed l i n e i n a i s from M i l l e r ( 1 9 5 9 ) . CWHa (•) , -CWHb (ffl) 62 4.1 R e l a t i o n s h i p s o f s a l a l b a s a l a r e a ( c m 2 « m ~ 2 ) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c omponents. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffl) . . . . 9 6 4 . 2 R e l a t i o n s h i p s o f s a l a l f o l i a r p r o d u c t i v i t y ( g » m ~ 2 ; CAGBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c o m p o n e n t s . D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffl) 97 x i 4.3 R e l a t i o n s h i p s o f s a l a l t o t a l b i o m a s s ( g « n r 2 ; TOTBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c o m p o n e n t s . D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffl) 98 4.4 R e l a t i o n s h i p s of a v e r a g e s h o o t h e i g h t (cm) and b a s a l d i a m e t e r (cm) of s a l a l w i t h 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l and d i r e c t r a d i a t i o n . CWHa ( • ) , CWHb (ffl) 100 4.5 R e l a t i o n s h i p s of a v e r a g e p r o d u c t i v i t y of s a l a l s h o o t s t o t r a n s m i s s i o n of g l o b a l and d i r e c t s o l a r r a d i a t i o n . CWHa (•), CWHb (ffi) 102 x i i L I S T OF APPENDICES 1 F o r e s t s t a n d c h a r a c t e r i s t i c s o f p l o t s . 133 2 Means and 95% c o n f i d e n c e i n t e r v a l s f o r u n d e r s t o r y c h a r a c t e r i s t i c s of p l o t s 136 3 C o r r e l a t i o n c o e f f i c i e n t s among o v e r s t o r y v a r i a b l e s f o r CWHa (H=10) 139 4 C o r r e l a t i o n c o e f f i c i e n t s among o v e r s t o r y v a r i a b l e s f o r CWHb, («=5) 140 5 C o r r e l a t i o n c o e f f i c i e n t s among o v e r s t o r y v a r i a b l e s f o r CWHb 3 (n=7) 141 6 C o r r e l a t i o n c o e f f i c i e n t s among o v e r s t o r y v a r i a b l e s f o r a l l t h r e e v a r i a n t s (n=22) 142 7 A l l o m e t r i c e q u a t i o n s f o r s t a n d i n g c r o p f o l i a r and t o t a l b i o m a s s o f s a l a l 143 8 A v e r a g e b i o m a s s ( i n grams) o f s a l a l l e a v e s by p l o t and 95% c o n f i d e n c e i n t e r v a l s ( b a c k t r a n s f o r m e d f r o m s q u a r e r o o t ) . . 1 4 6 9 R e g r e s s i o n s o f s a l a l v a r i a b l e s a g a i n s t p l o t a nd p r i s m b a s a l a r e a s and s t a n d d e n s i t i e s . Sample s i z e s : CWHa=lO, CWHb,=5, CWHb 3=7. E q u a t i o n s s i g n i f i c a n t a t p < 0.05. R e g r e s s i o n e q u a t i o n : Y = b0 + fc,X 147 10 The r e l a t i o n s h i p of a v e r a g e b a s a l d i a m e t e r o f s a l a l s h o o t s and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . . 1 4 8 x i i i 11 The r e l a t i o n s h i p o f t w i g p r o d u c t i v i t y (# CAG t w i g s ) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . E q u a t i o n : # C A G t w i g s » m - 2 = 193.81 - 219.93-MCC r 2 = 0 . 9 l , s =10.7 149 yx 12 The r e l a t i o n s h i p o f s a l a l b a s a l a r e a (cm 2/m 2) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . E q u a t i o n : B a s a l a r e a = 20.57 - 22.80-MCC r 2 = 0.76, s =2.0 150 13 The r e l a t i o n s h i p of s a l a l s h o o t p o s t u r e t o mean crown c o m p l e t e n e s s 151 14 D i s t r i b u t i o n of r e p o s e h e i g h t s o f s a l a l s h o o t s by p l o t . D i s t r i b u t i o n i s p e r c e n t of s h o o t d e n s i t y i n e a c h h e i g h t c l a s s 154 15 P e r c e n t f r e q u e n c y o f o c c u r r e n c e o f s p e c i e s f o u n d i n q u a d r a t s 155 16 A v e r a g e q u a d r a t (0.25 m 2) d e n s i t y o f u n d e r s t o r y s p e c i e s o t h e r t h a n s a l a l 156 17 L i s t o f c o v e r c l a s s e s f o r s p e c i e s p r e s e n t i n p l o t s . ....157 18 R e s u l t s o f s i t e d i a g n o s i s 158 19 R e g r e s s i o n c o e f f i c i e n t s o f e q u a t i o n s p r e d i c t i n g s o l a r r a d i a t i o n components from s t a n d c h a r a c t e r i s t i c s . Sample s i z e s : CWHa=6, CWHb=6. E q u a t i o n s s i g n i f i c a n t a t p ^ 0.10. R e g r e s s i o n e q u a t i o n : Y = ae 159 x i v 20 R e g r e s s i o n c o e f f i c i e n t s of e q u a t i o n s p r e d i c t i n g s o l a r r a d i a t i o n components from s t a n d c h a r a c t e r i s t i c s . Sample s i z e s : CWHa=6, CWHb=6. E q u a t i o n s s i g n i f i c a n t a t p £ 0.05. R e g r e s s i o n e q u a t i o n : Y = e 160 21 R e g r e s s i o n c o e f f i c i e n t s o f e q u a t i o n s p r e d i c t i n g s a l a l f r o m s i t e f a c t o r s d e r i v e d from h e m i s p h e r i c a l p h o t o g r a p h s . Sample s i z e s : CWHa=5, CWHb=6. R e g r e s s i o n e q u a t i o n : Y = ( C ( X - C ) ) / ( 1 + a(X-c)/b) 161 22 R e l a t i o n s h i p s o f s a l a l d e n s i t y ( # » n r 2 ) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l , . d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n components. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffl) 1 62 23 R e l a t i o n s h i p s o f p e r c e n t c o v e r o f s a l a l a nd 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c omponents. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa ( • ) , CWHb (ffl) 163 24 R e l a t i o n s h i p s of s a l a l DENSITY, CAGBIOM, FOLBIOM, TOTBIOM, and PCTCOVER t o R e i n e k e ' s SDI d e r i v e d from p l o t t r e e m easurements (SDI) and p r i s m s a m p l e s ( B A F S D I ) . D o t t e d l i n e s a r e s e p a r a t e r e l a t i o n s h i p s i n CWHa and CWHb 3 v a r i a n t s . . . . 1 6 4 xv ACKNOWLEDGMENTS I f i n d i t d i f f i c u l t t o o r d e r a c k n o w l e d g m e n t s when many p e r s o n s have made i m p o r t a n t c o n t r i b u t i o n s t o t h e d e v e l o p m e n t of t h i s p r o j e c t . To b e g i n , t h a n k s go t o my p a r e n t s and g r a n d f a t h e r who p r o v i d e d s u p p o r t . My s u p e r v i s o r , F . L . B u n n e l l , p r o v i d e d b a c k g r o u n d d a t a , f u n d i n g , and t h e i m p e t u s f o r d e v e l o p m e n t o f i d e a s . B e c a u s e o f him I have l e a r n e d t o be a more c o n f i d e n t , i n d e p e n d e n t r e s e a r c h e r . Committee member J.B. N y b e r g s t i m u l a t e d my t h i n k i n g w i t h p e n e t r a t i n g q u e s t i o n s . J . B . N y b e r g a l s o a r r a n g e d f o r e q u ipment l o a n s and p h o t o g r a p h d e v e l o p i n g from t h e B.C. M i n i s t r y o f F o r e s t s w h i c h were e s s e n t i a l f o r t h i s s t u d y and h e l p e d m i n i m i z e c o s t s . Committee members M.D. P i t t and J.H.G. S m i t h a l w a y s welcomed my q u e s t i o n s and p r o v i d e d v a l u a b l e comments and i n s i g h t . Many t h a n k s go t o f i e l d a s s i s t a n t s (and D e x i o n t e c h n i c i a n s ) R. McCann, A. McLeod, S. J a y , and D. H a r t f o r g r a c i o u s l y p u t t i n g up w i t h many l o n g , b o r i n g , and f r u s t r a t i n g f i e l d d a y s u n d e r some t r y i n g c o n d i t i o n s . Your p r o b i n g q u e s t i o n s , r e s o u r c e f u l n e s s , and good n a t u r e were a p p r e c i a t e d . S p e c i a l t h a n k s go t o T.A. B l a c k f o r a l w a y s f i n d i n g t i m e t o answer my q u e s t i o n s and a l s o f o r h i s s u g g e s t i o n s on m e t e o r o l o g i c a l measurements. B e c a u s e of t h e s u g g e s t i o n s o f R. K o r o l , m o n i t o r i n g of s o l a r r a d i a t i o n was i n c l u d e d i n t h i s s t u d y . x v i A U.B.C. U n i v e r s i t y G r a d u a t e F e l l o w s h i p and F a c u l t y o f F o r e s t y T e a c h i n g A s s i s t a n t s h i p s u p p o r t e d me f i n a n c i a l l y d u r i n g t h e t h r e e y e a r s . R e s e a r c h was s u p p o r t e d by t h e B.C. S c i e n c e C o u n c i l and C a n a d i a n F o r e s t S e r v i c e g r a n t s t h r o u g h F . L . B u n n e l l . F i e l d a s s i s t a n t s u p p o r t was p a r t l y f u n d e d by 1984 C a r e e r A c c e s s and 1985 C h a l l e n g e '85 g r a n t s . H o u s i n g was g r a c i o u s l y p r o v i d e d by C a n a d i a n F o r e s t P r o d u c t s i n Woss t h r o u g h J . K a p i t a n y and B.C. M i n i s t r y o f F o r e s t s a t t h e M e s a c h i e L a k e R e s e a r c h S t a t i o n . T h a n k s go t o L. P e t e r s o n , C. Ray, R. E l l i s a nd o t h e r s i n v o l v e d w i t h t h e IWIFR program. I am g r a t e f u l t o a l l o f t h e f o r e s t e r s who p r o v i d e d me w i t h maps and t h e i r t i m e . Some of t h o s e were: J . K a p i t a n y and E. M u l o c k , C a n a d i a n F o r e s t P r o d u c t s ; K. A l l e n , B. Murphy, and A. W a l k e r , B r i t i s h C o l u m b i a F o r e s t P r o d u c t s L t d . ; P. A f f l e c k , B. G i l l m o r e , B. K u r t z , J . L o f t u s , B. S h u c k l e , and M. V a n B r u e n , M a c M i l l a n B l o e d e l ; J . H a r w i j n e and R. T h u r l b o r n , Crown F o r e s t ; R. Meh, R. M i l l e r , and t h e f r i e n d l y s t a f f a t t h e M e s a c h i e Lake R e s e a r c h S t a t i o n , M i n i s t r y o f F o r e s t s . F i n a l t h a n k s a r e e x t e n d e d t o f e l l o w g r a d u a t e s t u d e n t s , whose d i s c u s s i o n s p r o v i d e d a much r i c h e r e d u c a t i o n t h a n i f t h i s s t u d y had been c o u r s e w o r k and f i e l d r e s e a r c h a l o n e . x v i i 1 CHAPTER 1. GENERAL INTRODUCTION M a n i p u l a t i n g f o r e s t s t a n d s has been s u g g e s t e d a s a t e c h n i q u e t o e n c o u r a g e f o r a g e p r o d u c t i o n f o r w i l d l i f e and d o m e s t i c s t o c k ( e . g . , Young e t a l . 1967). To manage f o r e s t s t a n d s f o r f o r a g e i t i s i m p o r t a n t t o know how c h a n g e s i n o v e r s t o r y a f f e c t t h e u n d e r s t o r y . S t u d i e s have examined t h e r e s p o n s e o f f o r a g e ( u n d e r s t o r y ) t o m a n i p u l a t i o n of t h e f o r e s t c a n o p y ( o v e r s t o r y ) and r e l a t i o n s h i p s have been drawn between t h e two ( f o r r e v i e w see B a r t l e t t and B e t t e r s 1983). U n d e r s t o r y v e g e t a t i o n a l s o competes w i t h t r e e s f o r m o i s t u r e ( e . g . , Tan e t a l . 1977) and l i k e l y n u t r i e n t s ( e . g . , Weetman e t a l . 1986). M a i n t a i n i n g d e n s e f o r e s t s t a n d s t o shade out t h e u n d e r s t o r y c a n r e d u c e t h i s c o m p e t i t i o n ( B l a c k e t a l . 1980; B l a c k and S p i t t l e h o u s e 1981). Few r e s e a r c h e r s have s t u d i e d p o t e n t i a l f a c t o r s r e g u l a t i n g u n d e r s t o r y p r o d u c t i o n ( e . g . , A n d e r s o n e t a l . 1969; Z a v i t k o v s k i 1976), and t h e s e s t u d i e s have had mixed r e s u l t s . C a u s a l r e l a t i o n s h i p s between o v e r s t o r y and u n d e r s t o r y have o f t e n been c o n s i d e r e d a s f u n c t i o n s o f t r a n s m i s s i o n of s o l a r r a d i a t i o n ( e . g . , A l a b a c k 1982). O b j e c t i v e s o f t h i s s t u d y a r e t r e a t e d i n s e p a r a t e c h a p t e r s and a r e : 1) t o examine t h e r e l a t i o n s h i p s o f s a l a l (Gaultheria shall on P u r s h ) d e n s i t y , f o l i a r p r o d u c t i v i t y , b i o m a s s , c o v e r , and h e i g h t t o f o r e s t s t a n d c h a r a c t e r i s t i c s and t o t e s t f o r d i f f e r e n c e s i n t h e r e l a t i o n s h i p s among s i t e s ; 2) t o s t u d y t h e r e l a t i o n s h i p s o f t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and 2 d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e s o l a r r a d i a t i o n t o f o r e s t s t a n d c h a r a c t e r i s t i c s ; 3) t o e v a l u a t e t h e e x t e n t t o w h i c h s a l a l a b u n d a n c e , g r o w t h and s h o o t s i z e a r e r e l a t e d t o t r a n s m i s s i o n of s o l a r r a d i a t i o n ; and 4) t o d i s c u s s t h e f o r e s t a nd w i l d l i f e management i m p l i c a t i o n s o f t h e s e f i n d i n g s . E m p h a s i s i n t h i s s t u d y i s on f o r e s t r y p r a c t i c e s i n u n t e n d e d , immature s t a n d s i n t h e C o a s t a l W e s t e r n Hemlock Zone on V a n c o u v e r I s l a n d . The r e s u l t s f r o m t h i s s t u d y w i l l s u p p l e m e n t l i m i t e d work p r e v i o u s l y done on u n d e r s t o r y - o v e r s t o r y r e l a t i o n s h i p s i n c l e a r c u t , m a t u r e , and o l d - g r o w t h f o r e s t s done by t h e F o r e s t r y - W i l d i f e G r o u p a t U.B.C. 3 REFERENCES A l a b a c k , P.B. 1982. D ynamics o f u n d e r s t o r y b i o m a s s i n S i t k a s p r u c e - w e s t e r n hemlock f o r e s t s of s o u t h e a s t A l a s k a . E c o l o g y . 63:1932-1948. A n d e r s o n , R . C , O.L. L o u c k s , and A.M. S w a i n . 1969. H e r b a c e o u s r e s p o n s e t o canopy c o v e r , l i g h t i n t e n s i t y , and t h r o u g h f a l l p r e c i p i t a t i o n i n c o n i f e r o u s f o r e s t s . E c o l o g y . 50:255-263. B a r t l e t t , E.T. and D.R. B e t t e r s ( e d s . ) . 1983. O v e r s t o r y - u n d e r s t o r y r e l a t i o n s h i p s i n w e s t e r n f o r e s t s . W e s t e r n R e g i o n a l R e s e a r c h P u b l . No. 1. C o l o r a d o S t a t e U n i v . Exp. S t a . , F o r t C o l l i n s , CO. B l a c k , T.A. and D.L. S p i t t l e h o u s e . 1981. M o d e l i n g t h e w ater b a l a n c e f o r w a t e r s h e d management, pp. 117-129 in: D.M. B a u m g a r t n e r ( e d . ) . P r o c . I n t e r i o r West W a t e r s h e d Mgt. A p r i l 8-10, 1980. Spokane, WA. B l a c k , T.A., C S . Tan, and J.U. Nnyamah. 1980. T r a n s p i r a t i o n i n t h i n n e d and u n t h i n n e d s t a n d s . Can. J . S o i l S c i . 60:625-631. Tan, C.S., T.A. B l a c k , and J.U. Nnyamah. 1977. C h a r a c t e r i s t i c s of s t o m a t a l d i f f u s i o n r e s i s t a n c e i n a D o u g l a s - f i r f o r e s t e x p o s e d t o s o i l w a t e r d e f i c i t s . Can. J . F o r . Res. 7:595-604. Weetman, G.F., A. G e r m a i n , and R. F o u r n i e r . 1986. F e r t i l i z e r s c r e e n i n g t r i a l s o f s t a g n a t e d S i t k a s p r u c e p l a n t a t i o n s on n o r t h e r n V a n c o u v e r I s l a n d , B.C. S o i l S c i . S o c . Am. J . ( s u b m i t t e d ) . Young, J.A., D.W. H e d r i c k , and R.F. K e n i s t o n . 1967. F o r e s t c o v e r and l o g g i n g - h e r b a g e and browse p r o d u c t i o n i n t h e m i x e d c o n i f e r o u s f o r e s t o f n o r t h e a s t e r n O r e g o n . J . F o r . 65:807-813. Z a v i t k o v s k i , J . 1976. G r o u n d v e g e t a t i o n b i o m a s s , p r o d u c t i o n , and e f f i c i e n c y of e n e r g y u t i l i z a t i o n i n some n o r t h e r n W i s c o n s i n f o r e s t e c o s y s t e m s . E c o l o g y . 57:694-706. 4 CHAPTER 2. RELATIONSHIPS BETWEEN SALAL UNDERSTORY AND FOREST OVERSTORY INTRODUCTION In t h e c o a s t a l f o r e s t s o f much o f t h e P a c i f i c N o r t h w e s t s a l a l {Gaul theria shall on P u r s h ) i s an i m p o r t a n t u n d e r s t o r y component f o r two m a j o r r e a s o n s . I t competes w i t h c o m m e r c i a l t r e e s p e c i e s f o r m o i s t u r e (Tan e t a l . 1977; P r i c e e t a l . 1986) and p o s s i b l y n u t r i e n t s (Weetman e t a l . 1986). S e c o n d , s a l a l i s a major w i n t e r f o r a g e f o r C o l u m b i a n b l a c k - t a i l e d d e e r (Odocoileus hemionus columbi anus R i c h a r d s o n ; Cowan 1945; Brown 1961; C r o u c h 1968; J o n e s 1975; R o c h e l l e 1980). W h i l e f o r e s t e r s may want t o m a i n t a i n d e n s e f o r e s t s t a n d s t o r e d u c e t h e abundance of s a l a l ( B l a c k e t a l . 1980; B l a c k and S p i t t l e h o u s e 1981), w i l d l i f e managers a r e c o n s i d e r i n g t h i n n i n g r e g i m e s t h a t m i g h t e n c o u r a g e s a l a l f o r a g e abundance (Nyberg e t a l . 1986). In e a c h c a s e t h e r e l a t i o n s h i p s o f s a l a l g r o w t h and abundance t o f o r e s t s t a n d c h a r a c t e r i s t i c s a r e c r i t i c a l . O t h e r t h a n t h e work o f Long and T u r n e r ( 1 9 7 5 ) , S t a n e k e t a l . ( 1 9 7 9 ) , Koch ( 1 9 8 3 ) , and B u n n e l l and V a l e s ( 1 9 8 6 ) , t h e s e r e l a t i o n s h i p s a r e n o t w e l l documented nor a r e t h e y t e s t e d f o r d i f f e r e n t p l a n t a s s o c i a t i o n s . T h i s s t u d y e x a m i n e s t h e r e l a t i o n s h i p s between s a l a l and f o r e s t s t a n d c h a r a c t e r i s t i c s . S p e c i f i c o b j e c t i v e s were t o : 1) d e v e l o p r e g r e s s i o n s p r e d i c t i n g s a l a l d e n s i t y , p r o d u c t i v i t y , 5 b i o m a s s , and c o v e r f r o m f o r e s t s t a n d c h a r a c t e r i s t i c s ; 2) i d e n t i f y t h e forms of t h e r e l a t i o n s h i p s between s a l a l v a r i a b l e s and f o r e s t s t a n d c h a r a c t e r i s t i c s ; 3) t e s t f o r d i f f e r e n c e s i n t h e r e l a t i o n s h i p s among b i o g e o c l i m a t i c v a r i a n t s ( K l i n k a e t a l . 1984) and between b i o g e o c l i m a t i c s u b z o n e s ( K r a j i n a 1965) and p l a n t a s s o c i a t i o n s ( O r l o c i 1964, 1965); 4) i d e n t i f y t h e b e s t f o r e s t s t a n d c h a r a c t e r i s t i c s t o use f o r p r e d i c t i n g s a l a l a bundance; and 5) examine t h e q u a l i t a t i v e r e l a t i o n s h i p o f s a l a l h e i g h t t o f o r e s t s t a n d c h a r a c t e r i s t i c s . 6 S T U D Y A R E A S Twenty-two p l o t s were sampl e d on V a n c o u v e r I s l a n d a nd 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 R e s e a r c h F o r e s t , UBCRF ( F i g . 2 . 1 ) . Ten p l o t s were i n t h e Gaultheria - W e s t e r n Hemlock - D o u g l a s - f i r (G-WH-DF) p l a n t a s s o c i a t i o n ( O r l o c i 1964, 1965) i n t h e V a n c o u v e r I s l a n d v a r i a n t (CWHa,; K l i n k a e t a l . 1984) of t h e C o a s t a l W e s t e r n Hemlock Dry Subzone (CWHa; K r a j i n a 1965). F o u r p l o t s a l s o were sampled i n t h e G-WH-DF p l a n t a s s o c i a t i o n i n t h e windward submontane v a r i a n t o f t h e C o a s t a l W e s t e r n Hemlock Wet Subzone (CWHb,). T h e s e f o u r p l o t s were a l l on t h e same h i l l s i d e i n t h e same s t a n d and were s e p a r a t e d by l e s s t h a n 800 m. One UBCRF p l o t was l o c a t e d i n t h e Vaccinium - Gaul theria - W e s t e r n Hemlock - D o u g l a s - f i r (V-G-WH-DF) p l a n t a s s o c i a t i o n ( O r l o c i 1964, 1965) i n t h e CWHb,. T h i s p l o t was combined w i t h t h e V a n c o u v e r I s l a n d CWHb, p l o t s f o r a n a l y s e s b e c a u s e i t had a s i m i l a r s o i l m o i s t u r e - n u t r i e n t r e g i m e ( h y g r o t o p e - t r o p h o t o p e ; K l i n k a 1 9 7 6). Seven a d d i t i o n a l p l o t s were sampl e d i n t h e V-G-WH-DF p l a n t a s s o c i a t i o n i n t h e l e e w a r d submontane v a r i a n t of t h e C o a s t a l W e s t e r n Hemlock Wet Subzone (CWHb 3). Th e s e s e v e n CWHb 3 p l o t s were a l l l o c a t e d on t h e same h i l l s i d e , i n t h e same s t a n d , and were s e p a r a t e d by l e s s t h a n 800 m. A l l p l o t s ( e x c e p t t h e UBCRF CWHb, p l o t i n o l d growth) were i n immature s t a n d s c o n t a i n i n g D o u g l a s - f i r {Pseudot suga menziesii ( M i r b . ) F r a n c o ) and w e s t e r n hemlock (Tsuga heterophylla ( R a f . ) S a r g . ) . O t h e r t r e e s p e c i e s e n c o u n t e r e d F i g u r e 2.1. P l o t l o c a t i o n s on V a n c o u v e r I s l a n d and a t t h e U.B.C. R e s e a r c h F o r e s t . were w e s t e r n r e d c e d a r (Thuja piicat a Donn), a m a b i l i s f i r (Abies amabilis ( D o u g l . ) F o r b e s ) , y e l l o w - c e d a r (Chamaecypari s nootkatensis (D. Don) S p a c h ) , and w e s t e r n w h i t e p i n e (Pinus monticola D o u g l . ) . U n d e r s t o r y v e g e t a t i o n was p r e d o m i n a n t l y s a l a l w i t h r e d h u c k l e b e r r y (Vaccinium parvifolium S m i t h ) and Oregon g r a p e (Mahonia nervosa P u r s h ) commonly p r e s e n t . S o i l s were H u m o - F e r r i c P o d z o l s on m o r a i n a l o r c o l l u v i a l v e n e e r ( K l i n k a e t a l . 1984). Of t h e s o i l c h a r a c t e r i s t i c s e x amined, LFH and Ae l a y e r d e v e l o p m e n t d i f f e r e d most among p l o t s . Mor humus was p o o r l y d e v e l o p e d on most p l o t s . 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 s 2123 mm i n t h e CWHa, 2682 mm i n t h e CWHb,, and CWHb 3 i s between t h e two ( K l i n k a e t a l . 1984). H y g r o t o p e - t r o p h o t o p e c o m b i n a t i o n s f o r t h e CWHa and CWHb 3 p l o t s were m o d e r a t e l y d r y t o s l i g h t l y d r y and n u t r i e n t p o o r t o medium. CWHb, p l o t s were s l i g h t l y d r y t o f r e s h a nd n u t r i e n t p o o r t o medium. C h a r a c t e r i s t i c s o f p l o t s a r e l i s t e d i n T a b l e TABLE 2.1 Descriptions of plots used to sample salal and forest stand characteristics Plot Location name Lat1tude-- Long 1tude Subzone var1 ant - Plant assoc. Aspect C ) Elev. (m) Slope (%) Age MCCa NTREEs" BA b Avg. DBHb (#/ha)(m'/ha) (mm) Avg. Ht (m) S1te C 1 ndex 1 Woss 50' 12' -- 126"28' CWHa G-WH-DF 230 430 30 28 0 91 2533 37 .7 131 12 . 4 36.4 2 Brewster 1 50' 07 ' -- 125*39' CWHa G-WH-DF 215 270 15 37 0. 78 1600 46 . 7 173 13 6 38.4 3 Brewster 2 50'07' • • 125'39' CWHa G-WH-DF 220 260 55 36 0. 55 533 21 .2 213 13 6 32.2 4 Mcrelght 50' 15 ' -- 125'37' CWHa G-WH-DF 218 150 48 53 0. 79 1778 53 .4 178 16 1 29.5 5 Youbou 1 48'54' • • 124'18' CWHa G-WH-OF 206 310 52 60 0 64 756 35 .0 235 25. 2 42.9 6 Youbou 2 48'54' • - 124'18' CWHa G-WH-DF 215 310 45 59 0 78 1733 34 .4 145 15. 6 35.3 7 Youbou 3 48'54' • - 124'18' CWHa G-WH-DF 173 200 9 34 0 35 267 14 . 8 219 15. 7 36.5 8 UBCRF M-G 49' 17 ' • • 122'28' CWHa G-WH-DF 115 375 10 44 0. 65 667 30 .7 222 18. 1 40. 4 d 9 Gordon R. 48'49' -- 124"19' CWHa G-WH-DF 261 630 43 42 0. .90 2711 54 .9 149 15 . 0 36.0 10 Raymond Cr. 48'52' -• 124'28' CWHa G-WH-DF 210 390 60 39 0, 75 1200 32 .5 165 15. .5 39.7 1 1 UBCRF V-G 49' 17 ' -• 122'28' CWHb. V-G-WH-DF 237 590 25 150+ 0. 90 1244 61 .0 210 15. 6 30.0 12 Harris Cr 1 48'37' -• 124' 15' CWHb, G-WH-DF 215 210 50 49 0. 64 844 25 .5 179 12. 8 26.5 13 Harris Cr 2 48'37' -• 124' 15' CWHb. G-WH-DF 221 200 40 50 0. 80 2000 62 .2 185 17. 6 36.5 14 Harris Cr 3 48'37' -- 124' 15' CWHbi G-WH-DF 232 200 50 48 0. 84 2444 67 .6 171 17 4 35.0 15 Harris Cr 4 48'37' • • 124" 15' CWHb, G-WH-DF 204 210 48 49 0. 79 2089 62 .0 182 13 9 27.9 21 Weeks L. 1 48'38' -• 123'52' CWHbi V-G-WH-DF 240 570 30 30 0. 58 889 10 . 1 110 9. 7 37.8 22 Weeks L. 2 48'36' -• 123'52' CWHbi V-G-WH-DF 240 570 30 30 0. 42 756 a .5 118 10. 3 37 .0 23 Weeks L. 3 48'36' - 123'52' CWHb i V-G-WH-DF 220 570 20 30 0. 81 2222 41 .6 144 13. 4 37.8 24 Weeks L. 4 48" 36' -• 123'52' CWHbi V-G-WH-DF 220 570 20 30 0. 64 1111 26 . 1 159 14 . 3 41 .0 25 Weeks L. 5 48'36' -• 123'52' CWHb. V-G-WH-DF 220 570 23 30 0. 74 1200 20 .0 138 13 . 6 41.4 26 Weeks L. 6 48" 36' -• 123'52' CWHb. V-G-WH-DF 219 550 19 30 0. 90 2622 38 .9 128 12 . 7 37.0 27 Weeks L. 7 48'36' -• 123'52' CWHbi V-G-WH-DF 214 600 22 30 0. 76 1378 17. 5 1 19 1 1 . 5 37.7 Mean crown completeness estimate of forest overstory cover. 'Derived from measurement of a l l trees > 8.0 cm within the plot. 100 year Douglas-fir reference based on total age. 'for western hemlock at 100 years total age. 10 METHODS P l o t s were s e l e c t e d t o encompass a ran g e o f o v e r s t o r y c o v e r and t o have t o p o g r a p h i c c h a r a c t e r i s t i c s s i m i l a r t o d e e r w i n t e r r a n g e s (sensu J o n e s and B u n n e l l 1984). S e l e c t i v e l y l o c a t i n g p l o t s i s l e s s t i m e c o n s u m i n g t h a n r a n d o m l y l o c a t i n g p l o t s and a v o i d s h e t e r o g e n e o u s s i t e s , t r a n s i t i o n s , and e c o t o n e s ( K o j i m a and K r a j i n a 1975). A l t h o u g h d e e r w i n t e r r a n g e s a r e t y p i c a l l y l o c a t e d i n o l d - g r o w t h f o r e s t s , young f o r e s t s managed a s b l a c k - t a i l e d d e e r w i n t e r r a n g e s may s e r v e as r e p l a c e m e n t s f o r o l d - g r o w t h w i n t e r r a n g e s i n t h e f u t u r e ( N y b e r g e t a l . 1986). C r i t e r i a u s e d t o s e l e c t p l o t s were: s t a n d i m m a t u r i t y and h o m o g e n e i t y o f f o r e s t c a n o p y s t r u c t u r e and s a l a l c o v e r , s t a n d a g e s 30-60 y e a r s , o v e r s t o r y c o v e r 35-95%, no t h i n n i n g , no f e r t i l i z a t i o n , no d e c i d u o u s t r e e s , s l o p e s 10-60%, a s p e c t 2 0 0 - 2 4 5 ° , and e l e v a t i o n 200-700 m. Under story P l o t s 9 x 25 m (0.0225 ha) were l a i d o ut w i t h t h e l o n g edge p a r a l l e l t o s l o p e c o n t o u r s . S a l a l was sampled i n 13 0.5 x 0.5 m (0.25 m 2) q u a d r a t s s y s t e m a t i c a l l y l o c a t e d a l o n g e a c h o f f o u r e q u i - s p a c e d t r a n s e c t s (n = 5 2 / p l o t ) . B e c a u s e o f s a l a l ' s c omplex, c l o n a l g r o w t h form (Koch 1983), i n d i v i d u a l p l a n t s were d i f f i c u l t t o d i s t i n g u i s h and t h e r e f o r e a s a l a l s h o o t was c o n s i d e r e d as t h e b a s i c sample u n i t . A s h o o t was d e f i n e d a s any stem e m e r g i n g from t h e l i t t e r l a y e r t h a t had r o o t s . In t h e f i e l d i t was o f t e n 11 d i f f i c u l t t o d i s t i n g u i s h s h o o t s f r o m n o n - r o o t e d stems; two stems o f t e n emerged f r o m t h e g r o u n d n e x t t o e a c h o t h e r , and when one stem was p u l l e d t o d e t e r m i n e h e i g h t , o t h e r stems were sometimes f o u n d t o be c o n n e c t e d t o i t j u s t below t h e l i t t e r o r humus l a y e r . S e v e r a l stems t h a t d i d n o t have r o o t s and were c o n n e c t e d t o a main r h i z o m e were c o n s i d e r e d a s one s h o o t . S h o o t s w i t h r o o t s c o u l d o b t a i n w a t e r and n u t r i e n t s and be somewhat i n d e p e n d e n t o f t h e r e s t o f t h e p l a n t . W i t h i n e a c h q u a d r a t , p e r c e n t c o v e r o f s a l a l f o l i a g e , e x c l u d i n g t h e c u r r e n t s e a s o n ' s g r o w t h ( t o a v o i d e r r o r s among p l o t s a s s o c i a t e d w i t h d a t e of s a m p l i n g ) , was v i s u a l l y e s t i m a t e d . A l l r o o t e d s a l a l s h o o t s were measured f o r b a s a l d i a m e t e r ( p o i n t above r o o t s and l i t t e r s u r f a c e ) , n a t u r a l r e p o s e h e i g h t ( v e r t i c a l d i s t a n c e f r o m p o i n t o f r o o t i n g t o i n t e r s e c t i o n w i t h a h o r i z o n t a l l i n e drawn from uppermost p o r t i o n o f p r e v i o u s s e a s o n ' s t w i g g r o w t h ) , " s t r e t c h " h e i g h t ( v e r t i c a l d i s t a n c e f r o m p o i n t of r o o t i n g t o uppermost p a r t o f p r e v i o u s s e a s o n ' s t w i g g r o w t h when t h e s h o o t was p u l l e d u p r i g h t ) , and c u r r e n t g r o w i n g s e a s o n ' s l e a v e s on a l l s h o o t s i n th e q u a d r a t were c o u n t e d . Random s a m p l e s of a t l e a s t 30 s a l a l s h o o t s t h a t encompassed a range o f s h o o t s i z e s i n e a c h o f t e n p l o t s were c l i p p e d , o v e n - d r i e d , and w e i g h e d t o d e v e l o p a l l o m e t r i c e q u a t i o n s p r e d i c t i n g f o l i a r and t o t a l s h o o t b i o m a s s ( V a l e s e t a l . i n p r e p . ) . S t a n d i n g c r o p f o l i a r and t o t a l b i o m a s s e s t i m a t e s were d e r i v e d f r o m t h e a l l o m e t r i c e q u a t i o n s and e x c l u d e d c u r r e n t a n n u a l g r o w t h b i o m a s s . C u r r e n t a n n u a l g r o w t h (CAG) l e a v e s were randomly s a m p l e d from e a c h p l o t 12 ( e x c e p t f o r p l o t 11 i n w h i c h p l o t 8 l e a f b i o m a s s was used) i n t h e f a l l a f t e r c o m p l e t i o n o f t h e s e a s o n ' s g r o w t h , o v e n - d r i e d a t 65 °C f o r 24 h o u r s and w e i g h e d t o t h e n e a r e s t 1 mg t o d e t e r m i n e a v e r a g e l e a f b i o m a s s . CAG f o l i a r b i o m a s s was d e r i v e d by m u l t i p l y i n g a v e r a g e l e a f b i o m a s s by number o f CAG l e a v e s p e r q u a d r a t . Overst ory F o r e s t o v e r s t o r y c o v e r has been measured i n a v a r i e t y o f ways ( f o r r e v i e w see V a l e s and B u n n e l l 1985) and many terms a r e u s e d t o d e f i n e t h e p r o p o r t i o n o f sky c o v e r e d by c a n o p y . I use "mean crown c o m p l e t e n e s s " (MCC) sensu B u n n e l l e t a l . ( 1 9 8 5 : 1 8 1 ) . MCC o f e a c h p l o t was measured w i t h a moosehorn ( R o b i n s o n 1947; Bonnor 1967) a t t h e c e n t e r o f e a c h q u a d r a t (« = 5 2 / p l o t ) . S t a n d age was o b t a i n e d by b o r i n g a t b r e a s t h e i g h t (1.3 m) f o u r d o m i n a n t t r e e s i n t h e p l o t o r n e a r b y ( l e s s t h a n 15 m fr o m a p l o t edge) and a d d i n g t h e age c o r r e c t i o n s f r o m W a t t s ( 1 9 8 3 : 4 0 2 ) . S i t e i n d e x was c a l c u l a t e d f o r t h e f o u r d o m i n a n t t r e e s b o r e d u s i n g t h e e q u a t i o n s from W a t t s ( 1 9 8 3 : 4 2 4 ) . T r e e s p e c i e s were r e c o r d e d and d i a m e t e r a t b r e a s t h e i g h t (DBH), t o p h e i g h t , and h e i g h t t o ba s e o f l i v e crown (HBLC; h e i g h t where t h e l o w e s t l i v e b r a n c h e s were a t t a c h e d t o t h e b o l e ) were measured f o r a l l t r e e s £ 8.0 cm DBH i n s i d e t h e p l o t . T r e e s < 8.0 cm DBH and > 20 cm t a l l were c o u n t e d . P o i n t samples were t a k e n w i t h a f o u r b a s a l a r e a f a c t o r (BAF„) p r i s m a t t h e f o u r p l o t c o r n e r s and p l o t c e n t e r ; s p e c i e s and DBH o f " i n " t r e e s were r e c o r d e d . 13 Definition of variables A l l u n d e r s t o r y measurements o f d e n s i t y , b i o m a s s , and c o v e r a r e r e p o r t e d a s p l o t a v e r a g e s d e r i v e d f r o m 52 0.25-m 2 q u a d r a t s . Measurements of s a l a l h e i g h t a r e r e p o r t e d a s p l o t a v e r a g e s o f a l l s h o o t s sampled. DENSITY -CAGBIOM -FOLBIOM -TOTBIOM -PCTCOVER-REPHT STRHT MCC NTREES BA AVGDIA SUMDIA HT CRNDEP a v e r a g e d e n s i t y o f s a l a l s h o o t s - n r 2 a v e r a g e CAG f o l i a r b i o m a s s of s a l a l (g-m (g - 2 ) e x c l u d e s m" a v e r a g e f o l i a r b i o m a s s o f s a l a l CAGBIOM) a v e r a g e f o l i a r + s t e m b i o m a s s of s a l a l ( g - n r 2 ; e x c l u d e s CAGBIOM) a v e r a g e q u a d r a t p e r c e n t c o v e r of s a l a l a v e r a g e r e p o s e h e i g h t o f s a l a l s h o o t s (cm) a v e r a g e s t r e t c h h e i g h t o f s a l a l s h o o t s (cm) mean crown c o m p l e t e n e s s o f p l o t ( a v e r a g e o f 52 moosehorn sam p l e s and r e p o r t e d a s a f r a c t i o n ) number o f p l o t t r e e s - h a " 1 ^ 8.0 cm b a s a l a r e a ( m 2 ' h a _ 1 ) o f p l o t t r e e s > 8.0 cm a v e r a g e DBH (mm) of p l o t t r e e s £ 8.0 cm - sum o f DBH (mm/225 m 2) o f p l o t t r e e s > 8.0 cm t r e e h e i g h t crown d e p t h (m) o f p l o t (HT - HBLC) t r e e s ^ of p l o t (m 2'ha p r i s m > 8.0 a v e r a g e a v e r a g e 8.0cm BAFBA - a v e r a g e s t a n d b a s a l a r e a cm d e t e r m i n e d from 5 BAF„ BAFDIA - a v e r a g e DBH (mm) of t r e e s BAFn p r i s m samples BAFTREES- a v e r a g e number o f t r e e s - h a -f r o m 5 BAF f l p r i s m s a m p l e s BAFBADIA- DBH (mm) of t r e e of a v e r a g e f r o m p r i s m samples BAFSDI - R e i n e k e ' s (1933) " s t a n d d e n s i t y i n d e x " f r o m p r i s m s a m p l i n g computed from B A F T R E E S - ( B A F B A D I A / 2 5 ) 1 • 6 (Long 1985) 8. 0 cm t r e e s > 1 ) o f t r e e s > 8.0 sam p l e s cm s a m p l e d by 5 1 > 8.0 cm d e t e r m i n e d b a s a l a r e a d e t e r m i n e d d e t e r m i n e d Analys es S a l a l q u a d r a t s a m p l e s and s h o o t measurements were t e s t e d f o r n o r m a l i t y w i t h i n p l o t s ( c o e f f i c i e n t o f skewness not s i g n i f i c a n t , S o k a l and R o h l f 1981:174) and h o m o g e n e i t y o f 1 4 v a r i a n c e among p l o t s (Fox and G u i r e 1976:68). T r a n s f o r m a t i o n s were n e c e s s a r y f o r a l l s a l a l v a r i a b l e s . A s u i t a b l e t r a n s f o r m a t i o n t o n o r m a l i z e t h e d a t a f o r one p l o t was n o t n e c e s s a r i l y t h e b e s t t r a n s f o r m a t i o n f o r o t h e r p l o t s . I u s e d a s i n g l e t r a n s f o r m a t i o n f o r a l l p l o t s w h i c h gave t h e l a r g e s t number of p l o t s h a v i n g g, n o t s i g n i f i c a n t (p > 0.05; minimum 14 o f 22 p l o t s ) . T r a n s f o r m a t i o n s u s e d were s q u a r e r o o t f o r q u a d r a t d e n s i t y , c o v e r , and s h o o t h e i g h t ; and c u be r o o t f o r a l l q u a d r a t b i o m a s s e s t i m a t e s . Means and c o n f i d e n c e i n t e r v a l s a r e r e p o r t e d b a c k t r a n s f o r m e d and q u a d r a t means a r e m u l t i p l i e d by 4 t o r e p r e s e n t 1 m 2. The b a c k t r a n s f o r m e d mean of e a c h s a l a l v a r i a b l e was r e g r e s s e d a g a i n s t s i n g l e and m u l t i p l e i n d e p e n d e n t v a r i a b l e s u s i n g f o r w a r d s e l e c t i o n , b a c kward s e l e c t i o n (MIDAS, Fox and G u i r e 1976), and a l l p o s s i b l e s u b s e t s r e g r e s s i o n (BMDP 9R, D i x o n 1983). B a c k t r a n s f o r m e d means were u s e d r a t h e r t h a n t h e t r a n s f o r m e d means b e c a u s e r e g r e s s i o n e s t i m a t e s o b t a i n e d f r o m e q u a t i o n s b a s e d on b a c k t r a n s f o r m e d means were u s u a l l y l o w e r and p r o v i d e d a more c o n s e r v a t i v e e s t i m a t e o f s a l a l a b u n d a n c e . B e s t r e g r e s s i o n s were t h o s e h a v i n g t h e l o w e s t s t a n d a r d e r r o r o f t h e e s t i m a t e (s ) and no t r e n d i n t h e r e s i d u a l s . yx R e g r e s s i o n s were d e v e l o p e d on u n t r a n s f o r m e d , l o g , o r r e c i p r o c a l l y t r a n s f o r m e d i n d e p e n d e n t v a r i a b l e s . A r e c i p r o c a l t r a n s f o r m a t i o n u s u a l l y gave a b e t t e r e q u a t i o n t h a n a l o g t r a n s f o r m a t i o n f o r most e q u a t i o n s and i n d e p e n d e n t v a r i a b l e s . F o r c o n s i s t e n c y h e r e , c u r v i l i n e a r r e g r e s s i o n s have t h e i n d e p e n d e n t v a r i a b l e s r e c i p r o c a l l y t r a n s f o r m e d . T h e r e seems 15 t o be no c o n s i s t e n t c u r v i l i n e a r f o r m o f r e g r e s s i o n f o r p u b l i s h e d e q u a t i o n s ( s e e r e v i e w s i n B a r t l e t t and B e t t e r s 1983). E q u a t i o n s b a s e d on a r e c i p r o c a l t r a n s f o r m a t i o n of t h e i n d e p e n d e n t v a r i a b l e g i v e u n r e a l i s t i c e s t i m a t e s n e a r z e r o . The r e s u l t s r e p o r t e d a r e t h e b e s t f o r t h i s d a t a s e t and a r e a p p l i c a b l e o n l y w i t h i n t h e r a n g e o f t h e d a t a . B e c a u s e e q u a t i o n s a r e d e v e l o p e d on p l o t means, r e g r e s s i o n s a r e i l l u s t r a t e d w i t h 95% c o n f i d e n c e i n t e r v a l s a r o u n d p l o t means t o show v a r i a b i l i t y of s a l a l s a m p l e s . R e p o r t e d s ^ > j c ' s b a s e d on r e g r e s s i o n s o f p l o t means may u n d e r e s t i m a t e t h e t r u e p o p u l a t i o n v a r i a t i o n . T e s t s of e q u a l r e g r e s s i o n s l o p e s and i n t e r c e p t s were computed w i t h a n a l y s e s of c o v a r i a n c e u s i n g t h e UBC SLTEST p r o g r a m (Le 1971). E x c e p t where o t h e r w i s e s t a t e d , a l l s t a t i s t i c a l t e s t s were a t a = 0.05. 1 6 R E S U L T S Regressions predicting salal abundances S i m p l e l i n e a r r e g r e s s i o n s p r e d i c t i n g e s t i m a t e s o f s a l a l a b u n d a n c e s a r e g i v e n i n T a b l e 2.2. E q u a t i o n s a r e p r e s e n t e d f o r MCC and t h e b e s t i n d e p e n d e n t v a r i a b l e s d e r i v e d f r o m p l o t t r e e measurements and p r i s m s a m p l e s . T h i s f o r m a t p e r m i t s e x a m i n a t i o n o f r e l a t i o n s h i p s b a s e d on o v e r s t o r y c o v e r , f a c t o r s o p e r a t i n g w i t h i n t h e p l o t , and f a c t o r s p o s s i b l y a f f e c t i n g s a l a l f r o m o u t s i d e t h e p l o t ( p r i s m s a m p l e s ) . R e g r e s s i o n s b a s e d on p l o t t r e e measurements and p r i s m s a m p l e s a l s o d e m o n s t r a t e t h e i n f l u e n c e of sample d e s i g n on a c c u r a c y of p r e d i c t i o n ( s y . x ) > E q u a t i o n s a r e p r e s e n t e d s e p a r a t e l y i n t h e CWHa and CWHb 3 t o show v a r i a b i l i t y ( r 2 ) a c r o s s s t a n d s o f d i f f e r e n t a g e s and l o c a t i o n s (CWHa) compared t o v a r i a b i l i t y w i t h i n a s t a n d (CWHb 3). R e g r e s s i o n s i n t h e CWHb, o n l y a r e e x c l u d e d due t o low sample s i z e and narrow r a n g e s of i n d e p e n d e n t v a r i a b l e s . E q u a t i o n s i n t h e CWHa were a l w a y s more v a r i a b l e t h a n t h o s e i n t h e CWHb 3 ( T a b l e 2.2; CWHa d e n s i t y v e r s u s MCC r2 = 0.93). M u l t i p l e r e g r e s s i o n s u s e d t h e same a p p r o a c h ( T a b l e 2 . 3 ) . V a r i a b l e s r e p r e s e n t i n g t h e m i d s t o r y , t r e e h e i g h t , l i v e crown r a t i o (CRNDEP/HT), s p e c i e s c o m p o s i t i o n and s i t e i n d e x were poor i n d e p e n d e n t v a r i a b l e s when u s e d s i n g l y a nd were not c o n s i s t e n t l y s e l e c t e d f o r i n c l u s i o n i n m u l t i p l e r e g r e s s i o n s . TABLE 2.2 S i m p l e l i n e a r r e g r e s s i o n e q u a t i o n s o f s a l a l v a r i a b l e s a s a f u n c t i o n of MCC, p l o t , and p r i s m v a r i a b l e s . Samp le s i z e s : CWHa=lO, CWHb,=5, CWHb 3 =7. E q u a t i o n s s i g n i f i c a n t a t p S 0 . 0 5 . R e g r e s s i o n e q u a t i o n : Y = fc0 + V a r i a n t X bo by yx D E N S I T Y : CWHa+b, 1/MCC 0 - 3 6 . 8 9 4 3 7 . 6 7 5 0 . 9 2 5 .23 1/SUMDIA 1/BAFSDI N . S . 4 - 2 6 . 4 5 6 82571 35631 0 . 8 6 0 . 7 3 7 .30 9 .50 CWHb 3 1/MCC 1/SUMDIA 1/BAFSDI - 1 1 9 . 0 4 - 4 5 . 0 5 9 - 4 3 . 4 8 1 113 .02 344340 45998 0 . 9 4 0 . 9 2 0 . 9 7 14 .26 15 .56 9 .87 CAGBIOM: CWHa 1/MCC 1/SUMDIA 1/BAFSDI - 3 3 . 8 0 4 N . S . - 3 5 . 4 3 9 32 .681 6851 1 38345 0 . 7 8 0 . 7 2 0 . 7 3 9 . 9 5 1 1 . 2 5 1 0 . 8 9 CWHb 3 1/MCC 1/SUMDIA 1/BAFSDI - 4 8 . 5 6 8 -18.752 -18 .386 4 4 . 5 6 8 133040 17887 0 . 9 5 0.91 0 . 9 6 4 .74 6 . 6 7 4.12 A l l 3 1/MCC 1/SUMDIA 1/BAFSDI - 3 8 . 5 7 5 - 8 . 5 8 6 5 -1 1 . 475 3 6 . 8 6 7 96966 17861 0 . 8 2 0 . 7 5 0 . 6 5 7.71 9 . 0 9 10 .90 FOLBIOM: CWHa 1/MCC 1/SUMDIA 1/BAFSDI - 8 4 . 6 1 4 N . S . - 9 3 . 6 1 0 8 4 . 1 4 0 182100 102310 0 . 6 6 0.61 0 .67 3 3 . 8 9 3 5 . 5 6 3 3 . 5 0 CWHb 3 MCC SUMDIA BAFSDI 2 3 0 . 6 6 1 5 2 . 3 6 1 7 9 . 7 4 - 2 2 7 . 4 8 - 0 . 0 1 8 1 7 - 0 . 1 8 9 8 5 0 .73 0 . 8 9 0 . 8 8 2 4 . 3 4 15 .84 16.51 A l l 3 1/MCC 1/SUMDIA 1/BAFSDI - 7 9 . 7 0 5 N . S . N . S . 8 6 . 7 2 9 206830 34535 0 . 6 2 0 . 6 6 0 . 5 8 3 0 . 4 9 2 9 . 0 4 3 2 . 9 0 TOTBIOM: CWHa 1/MCC 1/SUMDIA 1/BAFSDI - 2 9 5 . 5 5 N . S . - 3 3 7 . 9 5 3 0 5 . 2 5 690550 378460 0.61 0 .57 0 .64 137 .54 139 .57 131 .78 CWHb j MCC SUMDIA BAFSDI 5 5 0 . 13 3 5 8 . 3 2 4 2 6 . 2 4 - 5 4 7 . 8 9 - 0 . 0 4 3 0 2 - 0 . 4 5 5 0 3 0 . 7 6 0 . 8 8 0 . 8 9 5 5 . 2 8 3 8 . 1 9 3 6 . 2 0 A l l 3 1/MCC 1/SUMDIA BAFSDI - 2 5 8 . 1 2 N . S . 4 0 9 . 1 5 2 7 9 . 0 6 653580 - 0 . 3 2 3 9 5 0.61 0.61 0 .43 1 0 0 . 3 3 1 0 0 . 2 3 1 2 1 . 7 9 PCTCOVER: CWHa MCC SUMDIA 1/BAFSDI 7 6 . 3 4 4 5 1 . 2 3 0 N . S . - 7 3 . 6 3 7 - 0 . 0 0 5 3 1 18850 0 .42 0 .44 0 . 3 9 1 5 . 7 2 1 5 . 4 7 1 5 . 6 9 CWHb 3 MCC SUMDIA BAFSDI 1 0 0 . 6 5 6 1 . 6 2 3 74 .591 - 1 0 4 . 4 7 - 0 . 0 0 7 6 4 - 0 . 0 8 2 4 1 0 . 6 6 0 .87 0 .92 7 . 5 2 7 . 2 0 5 . 7 3 A l l 3 MCC SUMDIA BAFSDI 9 0 . 4 6 8 5 1 . 6 9 5 5 6 . 3 0 8 -91 .103 - 0 . 0 0 5 0 9 - 0 . 0 3 9 6 8 0 .58 0 .48 0 .48 12 .18 1 3 . 5 3 13 .58 flPrefix 1/ r e f e r s t o t h e r e c i p r o c a l o f t h e i n d e p e n d e n t v a r i a b l e . * C o e f f i c i e n t n o t s i g n i f i c a n t (p > 0 . 1 0 ) . 18 T A B L E 2.3 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 o f s a l a l v a r i a b l e s a s a f u n c t i o n o f M C C , p l o t , a n d p r i s m v a r i a b l e s . E q u a t i o n s s i g n i f i c a n t a t p < 0 . 0 5 . S a m p l e s i z e s : C W H a M O , C W H b . = 5 , C W H b J =7 V a r 1 a n t E q u a t i o n y x D E N S I T Y : C W H a + b . N . S . C W H b 3 - B 2 . 3 4 7 + 6 3 . 4 3 6 - 1 / M C C + 6 6 8 . 5 7 - 1 / B A 0 . 9 8 8 . 7 1 1 4 6 5 . 4 - 1 / B A - 4 2 0 1 . 2 - 1 / A V G D I A 0 . . 9 4 1 3 . 8 8 - 1 7 9 . 4 6 + 1 2 3 4 8 0 - 1 / B A F T R E E S + 2 3 2 1 3 • 1 / B A F D I A 0 . 9 9 6 . 0 6 C W H a - 7 9 . 3 5 2 + 4 1 . 1 7 0 - 1 / M C C + 2 9 4 . 3 2 - 1 / C R N D E P 0 , . 9 3 5 . 7 5 - 5 4 . 6 1 9 + 1 1 7 9 7 0 - 1 / S U M D I A + 3 5 3 . 1 7 • 1 / C R N D E P 0 , . 9 3 5 . 7 6 - 6 6 . 3 1 0 + 4 4 3 6 9 - 1 / B A F S D I + 2 0 5 . 6 4 • 1 / C R N D E P 0 . 8 2 9 . 6 3 C W H b 3 1 3 1 . 9 3 - 1 1 8 . 7 3 - M C C - 2 . 9 3 6 9 • C R N D E P 0 . . 9 9 2 . 6 7 5 7 2 . 3 5 - 1 / B A - 1 8 4 9 . 6 - 1 / A V G D I A 0 . , 9 3 5 . 9 6 - 6 8 . 5 0 7 + 5 0 3 8 3 - 1 / B A F T R E E S + 8 2 1 2 . 3 - 1 / B A F D I A 0 , . 9 9 2 . 1 0 A l l 3 - 8 4 . 3 9 1 + 4 2 . 4 5 2 - 1 / M C C - M 9 5 1 . 1 • 1 / A V G D I A + 2 3 2 . 2 4 • 1 / C R N D E P 0 , 9 3 5 . 1 2 - 4 3 . 9 9 5 + 1 1 5 7 9 0 - 1 / S U M D I A + 2 8 1 . 2 3 - 1 / C R N D E P O , 8 6 6 . 9 4 2 2 2 2 4 • 1 / B A F S D I - 4 0 2 0 . 7 • 1 / B A F D I A 0 . , 7 3 9 , , 5 0 C W H a - 2 4 6 . 5 1 + 1 1 4 . 3 1 - 1 / M C C + 1 0 4 6 . 1 • 1 / C R N D E P 0 . 9 2 17 , 3 9 - 1 7 9 . 1 4 + 3 2 9 5 7 0 - 1 / S U M D I A + 1 2 1 6 . 5 • 1 / C R N D E P 0 . 9 3 1 6 , . 0 9 - 2 1 6 . 4 5 + 1 2 6 2 7 3 • 1 / B A F S D I + 8 1 8 . 2 6 - 1 / C R N D E P 0 . 8 5 2 4 . 5 8 C W H b 3 N . S . 2 4 4 . 5 2 - 0 . 0 5 6 8 2 N T R E E S - 8 . 5 5 0 • C R N D E P 0 . 9 3 14 . 0 1 3 2 1 . 6 8 - 0 . 0 8 4 2 1 B A F T R E E S - 1 2 . 8 2 8 • C R N D E P 0 . 9 6 1 1 . 14 A l l 3 - 2 2 5 . 1 6 + 1 0 1 . O O - 1 / M C C + 1 0 9 6 0 - 1 / A V G D I A + 5 0 9 . 9 8 • 1 / C R N D E P 0 . 7 8 2 4 . 4 3 - 1 4 7 . 0 3 + 2 9 1 1 4 0 - 1 / S U M D I A + 7 8 6 8 . 3 • 1 / A V G D I A + 6 6 6 . 3 9 • 1 / C R N D E P 0 . 8 1 2 2 . 6 3 N . S . T O T B I O M : C W H a - 9 4 7 . 0 4 + 4 2 6 . 6 7 - 1 / M C C + 4 2 0 9 . 7 • 1 / C R N D E P - 7 0 1 . 5 6 + 1 2 3 9 3 0 - 1 / S U M D I A + 4 8 7 7 . 7 • 1 / C R N D E P - 8 4 8 . 2 4 + 4 7 8 0 2 8 • 1 / B A F S D I + 3 3 9 9 . 3 • 1 / C R N D E P 9 1 9 3 8 5 7 2 . 4 8 6 2 . 3 9 9 0 . 2 3 C W H b j N . S . 5 8 2 . 3 4 - 0 . 1 3 4 3 2 - N T R E E S - 2 0 . 8 3 8 • C R N D E P 7 6 8 . 2 8 - O . 2 0 0 7 9 B A F T R E E S - 3 1 . 0 6 2 • C R N D E P 9 3 9 7 3 3 . 6 3 2 2 . 1 1 A l 1 P C T C O V E R C W H a 3 - 6 2 9 . 7 2 + 3 3 5 . 8 5 - 1 / M C C + 2 6 3 8 . 4 • 1 / C R N D E P - 4 3 3 . 4 5 + 9 7 6 4 9 0 - 1 / S U M D I A + 3 1 3 0 . 3 - 1 / C R N D E P N . S . 1 5 9 . 6 1 - 1 2 0 . 6 4 M C C - 5 . 1 8 6 0 • C R N D E P 1 2 9 . 5 0 - 0 . 0 0 9 3 4 4 • S U M D I A - 5 . 9 8 7 0 • C R N D E P 1 2 8 7 . 6 - 1 / B A F B A - 1 2 4 5 0 - 1 / B A F D I A + 3 3 6 . 9 8 • 1 / C R N D E P C W H b 3 A l l 3 N . S . N . S . 1 2 0 . 7 3 0 . 0 3 6 2 3 - B A F T R E E S - 4 . 1 1 3 7 • C R N D E P 1 4 3 . 2 4 - 1 1 4 . 2 2 - M C C - 3 . 7 7 4 4 • C R N D E P 1 2 0 . 8 . 1 - 0 . 0 2 4 8 3 N T R E E S - O . 1 4 8 1 9 • A V G D I A - 3 . 6 3 17 • C R N D E P 1 1 6 . 1 6 - 0 . 0 2 6 4 6 B A F T R E E S - O . 1 1 0 1 3 - B A F D I A - 3 . 0 2 8 4 • C R N D E P 0 . 7 4 O . 7 9 0 . 6 9 0 . 7 8 0 . 8 2 0 . 9 3 0 . 7 1 0 . 6 6 0 . 6 7 8 3 . 5 8 7 6 . 0 6 1 2 . 1 7 1 0 . 3 4 9 . 4 4 5 . 8 5 1 0 . 3 1 1 1 . 4 9 1 1 . 3 8 a P r e f i x 1 / r e f e r s t o t h e r e c i p r o c a l o f t h e I n d e p e n d e n t v a r i a b l e . S l o p e s o f a d d i t i o n a l v a r i a b l e s n o t s i g n i f i c a n t l y d i f f e r e n t f r o m z e r o ( p > 0 . 1 0 ) . 19 Form of relationships The r e l a t i o n s h i p s between s a l a l d e n s i t y a nd f o r e s t v a r i a b l e s were c u r v i l i n e a r and s u g g e s t e d t h a t h y p e r b o l i c (1/X) or l o g a r i t h m i c ( l n ( X ) ) e q u a t i o n s c o u l d be u s e d . F o r e q u a t i o n s where l n ( X ) gave t h e b e s t p r e d i c t a b i l i t y ( s m a l l e s t s y . x ) i d i f f e r e n c e s between r e c i p r o c a l a nd l o g a r i t h m i c e q u a t i o n s were s m a l l , b u t where 1/X gave t h e b e s t p r e d i c t a b i l i t y , d i f f e r e n c e s were l a r g e . B e c a u s e t h e 1/X was o f t e n b e t t e r , I u s e d a h y p e r b o l a t o d e s c r i b e t h e r e l a t i o n s h i p between s a l a l d e n s i t y and s t a n d c h a r a c t e r i s t i c s f o r t h e ran g e o f t h e s e d a t a . S a l a l CAGBIOM was a l s o h y p e r b o l i c a l l y r e l a t e d t o s t a n d c h a r a c t e r i s t i c s ( T a b l e 2 . 2 ) , w i t h t h e 1/X t r a n s f o r m a t i o n g i v i n g c o n s i s t e n t l y b e t t e r e q u a t i o n s t h a n an l n ( X ) t r a n s f o r m a t i o n . S a l a l s t a n d i n g c r o p b i o m a s s was c o n s i s t e n t l y h y p e r b o l i c a l l y r e l a t e d t o s t a n d c h a r a c t e r i s t i c s i n t h e CWHa and a l s o f o r most combined d a t a e q u a t i o n s e x c e p t when BAFSDI was u s e d t o p r e d i c t TOTBIOM ( T a b l e 2 . 2 ) . FOLBIOM and TOTBIOM, however, were l i n e a r l y r e l a t e d t o s t a n d c h a r a c t e r i s t i c s i n t h e CWHb 3. Ranges o f i n d e p e n d e n t v a r i a b l e s i n t h e CWHb 3 were n a r r o w e r t h a n i n t h e CWHa and may have a f f e c t e d t h e b e s t f o r m of t h e r e g r e s s i o n . As w e l l , p l o t s 21 and 27 had bio m a s s e s t i m a t e s c o n s i d e r a b l y h i g h e r t h a n p r e d i c t e d a n d l i k e l y c o n t r i b u t e d t o t h e l i n e a r f o r m . The forms o f t h e r e l a t i o n s h i p s p r e d i c t i n g PCTCOVER were m o s t l y l i n e a r , e x c e p t f o r c o v e r p r e d i c t e d by BAFSDI i n t h e CWHa ( T a b l e 2 . 2 ) . 20 Differences among relationships Subzone e f f e c t s w i t h i n a p l a n t a s s o c i a t i o n (G-WH-DF CWHa a g a i n s t G-WH-DF CWHb,) and p l a n t a s s o c i a t i o n e f f e c t s w i t h i n (G-WH-DF CWHb, a g a i n s t V-G-WH-DF CWHb 3) and a c r o s s (G-WH-DF CWHa a g a i n s t V-G-WH-DF CWHb 3) s u b z o n e s were t e s t e d . R e s u l t s o f s l o p e t e s t s d i f f e r e d w i t h t h e i n d e p e n d e n t v a r i a b l e . E q u a t i o n s p r e d i c t i n g s a l a l d e n s i t y a s a f u n c t i o n o f r e c i p r o c a l l y ( l / X ) t r a n s f o r m e d MCC, SUMDIA, NTREES, p l o t SDI, and p r i s m BAFTREES were s i g n i f i c a n t l y d i f f e r e n t among t h e t h r e e v a r i a n t s (CWHa, CWHb,, CWHb 3), but d i d n o t d i f f e r between t h e CWHa and CWHb, v a r i a n t s i n t h e same p l a n t a s s o c i a t i o n , i n d i c a t i n g no sub z o n e e f f e c t . CWHbi and CWHb 3 e q u a t i o n s d i f f e r e d ( p l o t 22 was d r o p p e d from t h e s l o p e t e s t t o have r a n g e s o f i n d e p e n d e n t v a r i a b l e s n e a r l y e q u a l ) , i n d i c a t i n g a d i f f e r e n c e between p l a n t a s s o c i a t i o n s . E q u a t i o n s p r e d i c t i n g s a l a l d e n s i t y f r o m r e c i p r o c a l forms o f BA, BAFSDI, and BAFBA, however, d i d n o t d i f f e r among v a r i a n t s . No s i g n i f i c a n t d i f f e r e n c e s among v a r i a n t s were f o u n d f o r e q u a t i o n s p r e d i c t i n g CAGBIOM from 1/MCC, 1/SUMDIA, 1/SDI, 1/BA, and 1/BAFTREES. E q u a t i o n s d i f f e r e d s i g n i f i c a n t l y , however, w i t h 1/NTREES, 1/BAFSDI, and 1/BAFBA as i n d e p e n d e n t v a r i a b l e s . B e c a u s e forms o f r e l a t i o n s h i p s f o r TOTBIOM and FOLBIOM d i f f e r e d between t h e CWHa and CWHb 3 ( T a b l e 2 . 2 ) , c o v a r i a n c e a n a l y s i s t o t e s t f o r e q u a t i o n d i f f e r e n c e s i s n o t s t r i c t l y v a l i d . A c k n o w l e d g i n g t h i s , I s t i l l t e s t e d t h e r e g r e s s i o n s among v a r i a n t s u s i n g b o t h u n t r a n s f o r m e d and r e c i p r o c a l l y t r a n s f o r m e d i n d e p e n d e n t v a r i a b l e s t o e x p l o r e 21 p o t e n t i a l d i f f e r e n c e s . E q u a t i o n s d i d n o t d i f f e r u s i n g 1/MCC, 1/SUMDIA, 1/SDI, and 1/BAFTREES; h y p e r b o l i c e q u a t i o n s w i t h 1/BAFSDI and 1/BAFBA d i d . d i f f e r . E q u a t i o n s d i d n o t d i f f e r among v a r i a n t s f o r a l l u n t r a n s f o r m e d i n d e p e n d e n t v a r i a b l e s . T e s t s o f e q u a t i o n s w i t h 1/NTREES i n d i c a t e d a d i f f e r e n c e among v a r i a n t s when p r e d i c t i n g FOLBIOM, and 1/BA a d i f f e r e n c e among e q u a t i o n s p r e d i c t i n g TOTBIOM. B e c a u s e t h e r e i s some c o n s i s t e n c y o f t h e r e s u l t s u s i n g t h e two d i f f e r e n t r e g r e s s i o n f o r m s , e q u a t i o n s a r e l i k e l y n o t d i f f e r e n t . The c o n s i d e r a b l e v a r i a b i l i t y o f FOLBIOM and TOTBIOM e q u a t i o n s r e s u l t e d i n h i g h r e s i d u a l v a r i a n c e and t h u s t h e F - t e s t was n o t s i g n i f i c a n t . E q u a t i o n s p r e d i c t i n g PCTCOVER d i d n o t d i f f e r s i g n i f i c a n t l y w i t h any i n d e p e n d e n t v a r i a b l e . A l l s l o p e t e s t s were a t a = 0.05. Had a been s e t t o 0.01, a l l e q u a t i o n s e x c e p t 1/BAFSDI and 1/BAFBA p r e d i c t i n g TOTBIOM would have i n d i c a t e d no s i g n i f i c a n t d i f f e r e n c e among v a r i a n t s f o r e q u a t i o n s p r e d i c t i n g CAGBIOM, FOLBIOM, and TOTBIOM. R e c i p r o c a l l y t r a n s f o r m e d BAFBA and BAFSDI gave s l o p e t e s t r e s u l t s o p p o s i t e t h o s e of t r a n s f o r m e d MCC, SUMDIA, SDI, and BAFTREES f o r s a l a l d e n s i t y and b i o m a s s r e l a t i o n s h i p s . B e c a u s e 1/BAFSDI i s a p o o r e r p r e d i c t o r o f d e n s i t y t h a n p l o t s a m p l e s of 1/MCC, 1/SUMDIA, 1/SDI, and 1/NTREES i n t h e CWHa+b, ( T a b l e 2.2 i n p a r t ) , d e n s i t y r e l a t i o n s h i p s between t h e p l a n t a s s o c i a t i o n s a r e l i k e l y d i f f e r e n t . R e s u l t s were c o n s i s t e n t among a l l u n t r a n s f o r m e d i n d e p e n d e n t v a r i a b l e s f o r FOLBIOM and TOTBIOM. R e s u l t s o f s l o p e t e s t s u s i n g p l o t 1/SDI and 1/BAFSDI t o 22 p r e d i c t s a l a l d e n s i t y and b i o m a s s d i f f e r e d , b u t p a i r e d f - t e s t s between SDI and BAFSDI w i t h i n and a c r o s s v a r i a n t s f o u n d no d i f f e r e n c e s . E q u a t i o n s p r e d i c t i n g s a l a l b i o m a s s w i t h i n v a r i a n t s were a l w a y s s l i g h t l y b e t t e r u s i n g BAFSDI t h a n SDI (r2 d i f f e r e n c e s between 0.01 and 0.10). D i f f e r e n c e s among p l o t s between p l o t measurements and p r i s m s a m p l e s were n o t c o n s i s t e n t b e c a u s e p l o t s were sometimes l o c a t e d i n p a t c h e s o f d e n s e o r open s t a n d s . P l o t s l o c a t e d i n s t a n d gaps had an SDI l e s s t h a n t h a t o f BAFSDI ( e . g . , p l o t s 3, 7, 1 0), and p l o t s i n de n s e p a t c h e s had a h i g h e r SDI ( e . g . , p l o t s 1, 2, 4, 13, 15, 23, 2 6 ) . The e q u i v o c a l s l o p e t e s t s may r e s u l t f r o m t h e way t h a t p r i s m s a m p l e s a c c o u n t e d f o r t h e p a t t e r n of v a r i a t i o n o f p l o t s b e i n g d i s s i m i l a r f r o m t h e s u r r o u n d i n g s t a n d s . Ranges o f i n d e p e n d e n t v a r i a b l e s d i f f e r e d between p l o t t r e e measurements and p r i s m s a m p l e s ( s e e A p p e n d i c e s 1 and 2 4 ) . The r a n g e o f SDI and BAFSDI, and BA and BAFBA were s i m i l a r i n t h e CWHa, b u t p r i s m s a m p l e s had a n a r r o w e r r a n g e t h a n p l o t measurements i n t h e CWHb 3. The minima i n t h e CWHb 3 p l o t s a m p l e s o f SDI and BA were c l o s e r t o t h e minima i n t h e CWHa, but minima f o r p r i s m s a m p l e s of BAFSDI and BAFBA d i v e r g e d more ( e . g . , minimum SDI 295 i n CWHa, 233 i n CWHb 3; minimum BAFSDI 428 i n CWHa and 238 i n CWHb 3). Maxima f o l l o w e d t h e same p a t t e r n w i t h maxima more d i f f e r e n t w i t h p r i s m s a m p l e s t h a n w i t h p l o t measurements (maximum SDI 1335 i n CWHa, 1028 i n CWHb 3; maximum BAFSDI 1461 i n CWHa, 818 i n CWHb 3). Ranges o v e r l a p p e d more f o r measurements o f p l o t t r e e s (max-min SDI 23 733, BA 26.8) t h a n f o r p r i s m s a m p l e s (BAFSDI 390, BAFBA 1 2 . 8 ) . D i s c r e p a n c i e s between t h e two s a m p l i n g methods were l e s s p r o n o u n c e d f o r number o f t r e e s . R e c i p r o c a l t r a n s f o r m a t i o n s a c c e n t u a t e d t h e d i f f e r e n c e s between r a n g e s o f v a l u e s d e r i v e d by t h e two s a m p l i n g methods and l i k e l y c o n t r i b u t e d t o t h e e q u i v o c a l r e s u l t s . Relative predictability among independent variables O v e r s t o r y c o v e r (MCC) g e n e r a l l y was a good i n d e p e n d e n t v a r i a b l e p r e d i c t i n g s a l a l a b u n d a n c e s ( T a b l e 2 . 2 ) . R e l a t i o n s h i p s o f s a l a l t o MCC a s a p e r c e n t a r e i l l u s t r a t e d i n F i g s . 2.2-2.6. SUMDIA was t h e b e s t i n d e p e n d e n t v a r i a b l e d e r i v e d f r o m measurements o f p l o t t r e e s f o r p r e d i c t i n g s a l a l . E q u a t i o n s b a s e d on p l o t b a s a l a r e a , number o f t r e e s , o r SDI were not as good as u s i n g p l o t SUMDIA. SDI d e r i v e d f r o m p r i s m s a m p l e s was a b e t t e r i n d e p e n d e n t v a r i a b l e t h a n p r i s m s a m p l e s of b a s a l a r e a o r number o f t r e e s . T h e r e were o n l y modest d i f f e r e n c e s i n t h e s 's of e a c h •* y • x s a l a l v a r i a b l e among i n d e p e n d e n t v a r i a b l e s i n s e p a r a t e v a r i a n t s e x c e p t f o r FOLBIOM and TOTBIOM p r e d i c t e d by MCC i n t h e CWHb 3 and d e n s i t y p r e d i c t e d by BAFSDI ( T a b l e 2 . 2 ) . MCC was a p o o r e r p r e d i c t o r o f FOLBIOM and TOTBIOM t h a n o t h e r f o r e s t measurements i n t h e CWHb 3, a l t h o u g h MCC was good f o r combined d a t a . BAFSDI was a p o o r e r p r e d i c t o r o f d e n s i t y i n t h e CWHa+b, w i t h c o n s i d e r a b l e i n t e r - p l o t v a r i a t i o n of t r e e s i z e and s p a c i n g . O t h e r s a l a l v a r i a b l e s were p r e d i c t e d w e l l by BAFSDI i n t h e CWHa. I n t h e CWHb 3 where t r e e s were of 24 175.0 - i 30 40 50 60 70 80 90 100 MEAN CROWN COMPLETENESS (%) F i g u r e 2.2. The r e l a t i o n s h i p o f s a l a l d e n s i t y - n r 2 and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . Lower e q u a t i o n i s f o r CWHa and CWHb, combined d a t a (•), upper e q u a t i o n CWHb 3 (ffl). 25 100.0 - i F i g u r e 2.3. The r e l a t i o n s h i p o f f o l i a r p r o d u c t i v i t y ( g - n r 2 ; CAGBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa (•), CWHb, ( A ) , CWHb 3 (ffl). E q u a t i o n i s f o r c ombined d a t a . 26 250.0 - i 200.0-<N i MEAN CROWN COMPLETENESS (%) F i g u r e 2.4. The r e l a t i o n s h i p of s a l a l f o l i a r biomass ( g - n r 2 ; FOLBIOM) and 95% confi d e n c e i n t e r v a l s to mean crown completeness. CWHa (•), CWHb, ( A ) , CWHb3 (ffl). Equation r e p r e s e n t s combined data. 27 1000.0 - i 800.0-3> CO 30 40 50 60 70 80 90 100 MEAN CROWN COMPLETENESS (%) F i g u r e 2.5. The r e l a t i o n s h i p o f s a l a l t o t a l b i o m a s s ( g - m - 2 ; TOTBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa (•), CWHb, ( A ) , CWHb 3 (ffl). E q u a t i o n r e p r e s e n t s combined d a t a . 28 70.0 - i 3 0 4 0 50 60 70 8 0 90 100 MEAN CROWN COMPLETENESS (%) F i g u r e 2.6. The r e l a t i o n s h i p o f p e r c e n t c o v e r o f s a l a l a nd 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . CWHa (•), CWHb, ( A ) , CWHb 3 ( f f l ) . E q u a t i o n r e p r e s e n t s c o m b i n e d d a t a . 29 r e l a t i v e l y t h e same s i z e , BAFSDI p r e d i c t e d a l l s a l a l v a r i a b l e s w e l l . The p o o r e s t i n d e p e n d e n t v a r i a b l e f o r c o m b i n e d d a t a e q u a t i o n s was BAFSDI b e c a u s e e q u a t i o n s were f o u n d t o d i f f e r among v a r i a n t s . B o t h s a m p l i n g methods f o r s t a n d c h a r a c t e r i s t i c s a c c o u n t e d f o r n e a r l y e q u a l v a r i a t i o n i n i n d i v i d u a l v a r i a n t s , a l t h o u g h t h e two methods o f t e n y i e l d e d d i f f e r e n t r e s u l t s f o r t e s t s of e q u a l e q u a t i o n s among v a r i a n t s . B e c a u s e s i m p l e l i n e a r r e g r e s s i o n s a l r e a d y a c c o u n t e d f o r o v e r 90% o f t h e v a r i a t i o n i n s a l a l d e n s i t y , m u l t i p l e r e g r e s s i o n s e i t h e r a c c o u n t e d f o r v e r y l i t t l e o r no a d d i t i o n a l v a r i a t i o n ( T a b l e 2 . 3 ) . Where a d d i t i o n a l v a r i a b l e s were s i g n i f i c a n t a nd i m p r o v e d t h e p r e d i c t a b i l i t y of b i o m a s s o r c o v e r e q u a t i o n s , crown d e p t h (CRNDEP) was t h e most i m p o r t a n t added v a r i a b l e , b e i n g i n c l u d e d i n a l l b u t one m u l t i p l e r e g r e s s i o n ( T a b l e 2 . 3 ) . S a l a l was c o n s i s t e n t l y i n v e r s e l y r e l a t e d t o crown d e p t h . E q u a t i o n s p r e d i c t i n g FOLBIOM and TOTBIOM were more v a r i a b l e t h a n t h o s e f o r CAGBIOM. The d i f f e r e n c e s may be due t o e s t i m a t i n g s t a n d i n g c r o p b i o m a s s i n d i r e c t l y f r o m a l l o m e t r i c e q u a t i o n s t h a t were more v a r i a b l e t h a n t h e more d i r e c t e s t i m a t e o f CAGBIOM. Salal s hoot hei ght Mean r e p o s e and s t r e t c h h e i g h t showed c o n s i d e r a b l e v a r i a b i l i t y when r e l a t e d t o MCC among t h e CWHa p l o t s , b u t g e n e r a l l y , s h o o t h e i g h t p e a k e d between 65 and 80% MCC ( F i g . 2 . 7 ) . CWHb, and CWHb 3 p l o t s s a m p l e d w i t h i n s t a n d s 30 100.0-1 8 0 . 0 -6 0 . 0 -4 0 . 0 -2 0 . 0 -0 .0 3 0 — r — 4 0 6 0 l 6 0 7 0 l 8 0 —1 1 9 0 100 MEAN CROWN COMPLETENESS (%) Figure 2.7. The rela t i o n s h i p of average height of s a l a l and 95% confidence i n t e r v a l s to mean crown completeness (a) repose, (b) stretch. CWHa (•), CWHb, (A), CWHb3 (a). i n d i c a t e d a s i m i l a r p a t t e r n of h e i g h t . S h o o t s i n some of t h e CWHa p l o t s were l a r g e r t h a n i n CWHb 3 p l o t s a t n e a r l y e q u a l MCC, l i k e l y due, i n p a r t , t o age d i f f e r e n c e s . The r e l a t i o n s h i p o f s a l a l h e i g h t t o o t h e r s t a n d c h a r a c t e r i s t i c s i n d i c a t e d s i m i l a r p a t t e r n s , t h o u g h more v a r i a b l e t h a n t o MCC. DISCUSSION S a l a l abundance was g e n e r a l l y w e l l r e l a t e d t o f o r e s t s t a n d c h a r a c t e r i s t i c s i n t h e s e p a r a t e v a r i a n t s , p l a n t a s s o c i a t i o n s , a nd f o r combined d a t a ( T a b l e s 2.2 and 2 . 3 ) . D e n s i t y was c l o s e l y r e l a t e d t o s i n g l e s t a n d c h a r a c t e r i s t i c s i n th e two p l a n t a s s o c i a t i o n s . R e g r e s s i o n s a c c o u n t e d f o r l e s s v a r i a t i o n i n s a l a l b i o m a s s and c o v e r i n t h e CWHa t h a n i n t h e CWHb 3 v a r i a n t s due t o age and s i t e d i f f e r e n c e s among t h e CWHa p l o t s . D i f f e r e n c e s i n r e l a t i o n s h i p s among v a r i a n t s , between s u b z o n e s , o r between p l a n t a s s o c i a t i o n s were f o u n d when t e s t i n g f o r p l a n t a s s o c i a t i o n e f f e c t s on d e n s i t y p r e d i c t e d f r o m most v a r i a b l e s . The CWHb 3 p l o t s had a g r e a t e r d e n s i t y ( F i g . 2.2) of g e n e r a l l y s m a l l e r s h o o t s ( F i g . 2.7) t h a n t h e o t h e r p l o t s . E q u a t i o n s among v a r i a n t s d i d n o t d i f f e r f o r p r e d i c t i n g c u r r e n t a n n u a l g r o w t h f o l i a r b i o m a s s . R e s u l t s o f t e s t s o f FOLBIOM and TOTBIOM e q u a t i o n s among v a r i a n t s were e q u i v o c a l , and b e c a u s e t h e t e s t s were n o t s t r i c t l y v a l i d , t h e r e s u l t s a r e somewhat i n c o n c l u s i v e , and may be m i s l e a d i n g ( p o s s i b l e Type I I e r r o r ) . Most s t a t i s t i c a l t e s t s r e v e a l e d t h a t r e l a t i o n s h i p s do n o t d i f f e r , t h o u g h 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 w i t h i n v a r i a n t s ( F i g s . 2.4 and 2 . 5 ) . B i o m a s s i n p l o t s 5 and 6 was g r e a t e r t h a n o t h e r CWHa p l o t s a t a g i v e n l e v e l o f an i n d e p e n d e n t v a r i a b l e ( e . g . , F i g s . 2.3-2.5; A p p e n d i x 24) and c o n t r i b u t e d t o t h e g r e a t e r v a r i a b i l i t y of t h e CWHa e q u a t i o n s . S l o p e s o f e q u a t i o n s among v a r i a n t s p r e d i c t i n g 33 FOLBIOM and TOTBIOM from MCC e x c l u d i n g p l o t s 5 and 6 d i d n o t d i f f e r , however, t h e i n t e r c e p t s f o r FOLBIOM e q u a t i o n s d i d d i f f e r . P l o t 6 had g r e a t e r p r o d u c t i v i t y and b i o m a s s o f s a l a l t h a n p l o t 5 even t h o u g h p l o t 6 was i n a d e n s e r f o r e s t . P l o t 6, however, r e c e i v e d more s o l a r r a d i a t i o n t h a n p l o t 5 ( C h a p t e r s 3 and 4 ) . S e v e r a l t e s t s o f e q u a l r e g r e s s i o n e q u a t i o n s were i n c o n s i s t e n t w i t h t h e m a j o r i t y o f r e s u l t s . No d i f f e r e n c e s were f o u n d among e q u a t i o n s p r e d i c t i n g d e n s i t y f r o m p l o t BA and p r i s m BAFSDI and BAFBA. D i f f e r e n c e s i n b i o m a s s e q u a t i o n s were f o u n d w i t h BAFSDI, BAFBA, and s e v e r a l c a s e s w i t h NTREES a n d BA. A l l e q u i v o c a l r e s u l t s were w i t h a r e c i p r o c a l t r a n s f o r m a t i o n t h a t had a more p r o n o u n c e d e f f e c t on r a n g e s o f o v e r l a p o f i n d e p e n d e n t v a r i a b l e s t h a n u n t r a n s f o r m e d d a t a . P r i s m s a m p l e s a c c o u n t e d f o r p a t c h i n e s s o f p l o t s and p a t t e r n o f v a r i a t i o n among p l o t s d i f f e r e n t t h a n p l o t t r e e measurements. I c o n c l u d e t h a t t h e d i f f e r e n c e s i n r e l a t i o n s h i p s e i t h e r among v a r i a n t s o r between p l a n t a s s o c i a t i o n s a r e p a r t l y a f u n c t i o n o f s a m p l i n g method. P l o t SDI was a measurement o f p l o t t r e e s r a t h e r t h a n d e r i v e d f r o m a sample, p r e d i c t e d s a l a l n e a r l y a s w e l l as BAFSDI, and t h e r e were no d i f f e r e n c e s among e q u a t i o n s p r e d i c t i n g s a l a l b i o m a s s . B e c a u s e p l o t t r e e measurements were more p r e c i s e t h a n p r i s m s a m p l e s and sampl e d t h e same a r e a t h a t s a l a l was s a m p l e d i n , I f e e l t h a t ' t e s t s o f e q u a l r e g r e s s i o n e q u a t i o n s u s i n g p l o t measurements a r e t h e most a p p r o p r i a t e . S o i l n u t r i e n t and m o i s t u r e s t a t u s and t r e e s p e c i e s were s i m i l a r i n b o t h p l a n t a s s o c i a t i o n s and s i t e e f f e c t s a l o n e may n o t e x p l a i n t h e d i f f e r e n c e s i n d e n s i t y . S a l a l s h o o t s a r e v e r y s h o r t and numerous i n c l e a r c u t s and on e x p o s e d a r e a s ( p l o t mean d e n s i t y i n a young c l e a r c u t a s h i g h a s 189 s h o o t s « m " 2 , B u n n e l l and V a l e s u n p u b l . d a t a ) . W i t h t i m e , s e l f t h i n n i n g c a u s e d by c o m p e t i t i o n r e d u c e s d e n s i t y a l l o w i n g i n d i v i d u a l s h o o t s t o grow l a r g e r . As a s t a n d d e v e l o p s and c l o s e s , l i g h t t r a n s m i s s i o n i s r e d u c e d and a l s o t h e r e i s i n c r e a s e d c o m p e t i t i o n w i t h t r e e s f o r m o i s t u r e and n u t r i e n t s t h a t may a f f e c t s a l a l . B e c a u s e p l o t s i n t h e CWHb 3 were i n a younger s t a n d t h a n most o t h e r s t a n d s s a m p l e d , t h e g r e a t e r d e n s i t y may be an age e f f e c t r a t h e r t h a n a p l a n t a s s o c i a t i o n e f f e c t . No d a t a a r e a v a i l a b l e on s u c c e s s i o n a l t r e n d s i n s a l a l d e n s i t y , a l t h o u g h Long and T u r n e r ( 1 9 7 5 ) , T u r n e r and Long ( 1 9 7 5 ) , and Long (1977) f o u n d t h a t s a l a l s t a n d i n g c r o p b i o m a s s , c u r r e n t a n n u a l g r o w t h b i o m a s s , and c o v e r , r e s p e c t i v e l y , were g r e a t e r i n a 2 2 - y e a r - o l d s t a n d t h a n i n o l d e r s t a n d s . O t h e r r e s e a r c h e r s have f o u n d a n y t h i n g f r o m weak t o s t r o n g r e l a t i o n s h i p s between u n d e r s t o r y and o v e r s t o r y i n a v a r i e t y o f s t a n d t y p e s ( f o r r e v i e w s see S p e c h t and Morgan 1981; B a r t l e t t and B e t t e r s 1983). Forms of r e l a t i o n s h i p s a r e a l s o d i v e r s e . Pyke and Zamora (1982) f o u n d a h y p e r b o l i c r e l a t i o n s h i p o f s h r u b p r o d u c t i o n t o MCC i n I d a h o . B u n n e l l and V a l e s (1986) f o u n d a h y p e r b o l i c r e l a t i o n s h i p o f s a l a l d e n s i t y t o MCC mea s u r e d w i t h a moosehorn and a l i n e a r one between s a l a l c o v e r and MCC. B u n n e l l and V a l e s (1986) s t a t e d t h a t h y p e r b o l i c r e l a t i o n s h i p s would be e x p e c t e d f o r p r o d u c t i v i t y v a r i a b l e s b e c a u s e s m a l l c h a n g e s i n MCC a t low l e v e l s o f MCC have a 35 g r e a t e r e f f e c t on c o m p e t i t i o n , t h r o u g h f a l l , and l i g h t t r a n s m i s s i o n ( C h a p t e r 3) t h a n a t h i g h e r l e v e l s of MCC. They a l s o s t a t e d t h a t l i n e a r r e l a t i o n s h i p s o f u n d e r s t o r y c o v e r t o MCC w o u l d be e x p e c t e d b e c a u s e u n d e r s t o r y c o v e r may n o t n e c e s s a r i l y be r e l a t e d t o a s i n g l e p r o d u c t i v i t y v a r i a b l e . R e s u l t s of r e g r e s s i o n s h e r e were h y p e r b o l i c f o r s a l a l d e n s i t y and b i o m a s s and were l i n e a r f o r c o v e r . The l i n e a r r e l a t i o n s h i p s f o u n d f o r some r e g r e s s i o n s i n t h e CWHb 3 may be a r e s u l t o f a narrow r a n g e o f t h e i n d e p e n d e n t v a r i a b l e t r u n c a t i n g t h e d i s t r i b u t i o n ( B u n n e l l and V a l e s 1986) o r t h e i n f l u e n c e o f two p l o t s . Long and T u r n e r (1975) p r e s e n t e d an i n v e r s e c u r v i l i n e a r r e l a t i o n s h i p o f s a l a l b i o m a s s t o f o l i a g e b i o m a s s of f o r e s t o v e r s t o r y . The b e s t i n d e p e n d e n t v a r i a b l e s ( l o w e s t s ^ > x ' s ) p r e d i c t i n g s a l a l were c o n s i s t e n t among d e p e n d e n t v a r i a b l e s , f o r s e p a r a t e v a r i a n t s , and f o r c ombined d a t a . Shaw and R i p l e y ( 1 9 6 2 ) , Young e t a l . ( 1 9 6 7 ) , and Pyke and Zamora (1982) b e l i e v e d t h a t o v e r s t o r y c o v e r was a b e t t e r p r e d i c t o r o f u n d e r s t o r y t h a n b a s a l a r e a . A l t h o u g h r e l a t i o n s h i p s o f s a l a l t o p l o t b a s a l a r e a o r number of t r e e s were a c c e p t a b l e , t h e y were no t as good as MCC o r SUMDIA. Where e q u a t i o n s were f o u n d n o t t o d i f f e r among v a r i a n t s , MCC was a l m o s t a s good a s , o r b e t t e r t h a n SUMDIA f o r c o m b i n e d d a t a . W i t h i n v a r i a n t s , BAFSDI was a good i n d e p e n d e n t v a r i a b l e , b u t b e c a u s e e q u a t i o n s among v a r i a n t s d i f f e r e d f o r e s t i m a t e s o f s a l a l b i o m a s s p r e d i c t e d f r o m BAFSDI, comb i n e d d a t a e q u a t i o n s were p o o r e r t h a n u s i n g MCC o r SUMDIA. The d i f f e r e n c e between r e s u l t s o f t h e two s a m p l i n g methods was 36 u n e x p e c t e d . F o r e s t i n v e n t o r i e s d e r i v e d f r o m p l o t s a m p l i n g a r e t i m e - c o n s u m i n g . P o i n t s a m p l e s o b t a i n e d f r o m p r i s m s a m p l i n g a r e e a s i e r a nd q u i c k e r t o sample. S m a l l e r t r e e s a r e sampled more i n t e n s i v e l y w i t h p l o t s a m p l i n g b e c a u s e t r e e s a r e sampled w i t h p r o b a b i l i t y p r o p o r t i o n a l t o t r e e f r e q u e n c y , whereas p o i n t s a m p l i n g i s p r o p o r t i o n a l t o s i z e and l a r g e r d i a m e t e r t r e e s a r e sampled w i t h t h e same i n t e n s i t y a s s m a l l e r d i a m e t e r c l a s s e s ( W a t ts 1983). S m a l l e r t r e e s p r o b a b l y i n f l u e n c e t h e u n d e r s t o r y by r e d u c i n g t r a n s m i s s i o n o f r a d i a t i o n o r by c o m p e t i t i o n . W i t h a l a r g e enough sample s i z e , r e s u l t s o f p o i n t s a m p l i n g w i l l a p p r o x i m a t e t h o s e o f p l o t s a m p l i n g (J.H.G. S m i t h , p e r s . comm., U . B . C ) . In t h e CWHa where i n t e r - p l o t v a r i a t i o n was g r e a t e r , r e g r e s s i o n s p r e d i c t i n g s a l a l d e n s i t y u s i n g i n d e p e n d e n t v a r i a b l e s d e r i v e d f r o m s a m p l e s o f t h e s t a n d ( p r i s m ) were p o o r e r t h a n u s i n g p l o t s a m p l e s . S a l a l b i o m a s s and c o v e r , however, were w e l l r e l a t e d t o p r i s m samples i n s e p a r a t e v a r i a n t s ( T a b l e 2 . 2 ) . P r i s m s a m p l e s i n c l u d e d t r e e s b o t h i n s i d e and o u t s i d e t h e p l o t w h i c h would have an i n f l u e n c e on t r a n s m i s s i o n of s o l a r r a d i a t i o n . T r e e s i n s i d e t h e p l o t w o u l d be c o m p e t i n g f o r s o i l m o i s t u r e and n u t r i e n t s , a n d a l s o i n f l u e n c e t r a n s m i s s i o n o f r a d i a t i o n . The i n d e p e n d e n t v a r i a b l e s s e l e c t e d i n r e g r e s s i o n s s u g g e s t t h a t s o l a r r a d i a t i o n i s i m p o r t a n t f o r s a l a l d e n s i t y and b i o m a s s . A n d e r s o n e t a l . (1969) and Z a v i t k o v s k i (1976) f o u n d p o s t i t i v e r e l a t i o n s h i p s between u n d e r s t o r y a bundance and s o l a r r a d i a t i o n u n d e r f o r e s t c a n o p i e s . A l a b a c k (1982) b e l i e v e d t h a t 37 t r a n s m i s s i o n o f s o l a r r a d i a t i o n was i m p o r t a n t f o r u n d e r s t o r y g r o w t h , b u t t h a t i n d i r e c t m e a sures of f o r e s t s t r u c t u r e were d i f f i c u l t t o use as c a u s a l f a c t o r s a f f e c t i n g u n d e r s t o r y . T r a n s m i s s i o n o f s o l a r r a d i a t i o n h as been f o u n d t o be r e l a t e d t o MCC, SUMDIA, and b a s a l a r e a ( e . g . , W e l l n e r 1948; M i l l e r 1959), w i t h MCC and SUMDIA b e i n g b e t t e r p r e d i c t o r s t h a n b a s a l a r e a ( C h a p t e r 3 ) . O v e r s t o r y f o l i a g e and c o n s e q u e n t l y c o m p e t i t i o n (Horn 1971) i s a l s o c o r r e l a t e d w i t h MCC and SUMDIA. B e c a u s e s a l a l d e n s i t y was s t r o n g l y r e l a t e d t o s i n g l e p l o t v a r i a b l e s , d e n s i t y i s p r o b a b l y s t r o n g l y i n f l u e n c e d by i n t e r - s p e c i f i c c o m p e t i t i o n w i t h t r e e s a s w e l l a s by i n t r a - s p e c i f i c c o m p e t i t i o n and r a d i a t i o n , c o n s e q u e n t l y a f f e c t i n g b i o m a s s p e r u n i t a r e a . M u l t i p l e r e g r e s s i o n s p r e d i c t i n g s a l a l b i o m a s s and c o v e r i n c l u d e d CRNDEP, w h i c h a f f e c t s t r a n s m i s s i o n o f s o l a r r a d i a t i o n and would be c o r r e l a t e d w i t h s t a n d age and c o m p e t i t i o n t h r o u g h t r e e s p a c i n g and amount o f o v e r s t o r y f o l i a g e . The r e l a t i o n s h i p s between s a l a l a b undance and t r a n s m i s s i o n of s o l a r r a d i a t i o n a r e examined i n C h a p t e r 4. S a l a l h e i g h t has n o t been e x t e n s i v e l y s t u d i e d . Koch (1983) f o u n d an i n v e r s e l i n e a r r e l a t i o n s h i p o f a v e r a g e s h o o t h e i g h t t o MCC between 30 and 91% MCC, and b a s a l a r e a 0 t o 66 m 2 « h a " 1 b a s e d on f i v e p l o t s . B u n n e l l and V a l e s (1986) f o u n d a p a r a b o l i c r e l a t i o n s h i p o f a v e r a g e h e i g h t t o MCC measured w i t h a moosehorn on 19 p l o t s . The c o n s i s t e n t peak f o u n d i n t h i s s t u d y o f s a l a l h e i g h t u n d e r MCC between 65 t o 80% among t h e t h r e e v a r i a n t s i n d i c a t e s t h a t a p a r a b o l i c r e l a t i o n s h i p may 38 a p p l y f o r d i f f e r e n t s i t e s . The l o c a t i o n of t h e peak, however, may v a r y w i t h age, d e n s i t y ( c o m p e t i t i o n ) , o r m i c r o s i t e d i f f e r e n c e s . S h o o t s i n s t a n d s o f t h e same age may be s h o r t e r i n more open a r e a s e i t h e r b e c a u s e of m o i s t u r e s t r e s s (Swank 1972) o r no c o m p e t i t i o n f o r l i g h t . V e r y d e n s e c a n o p i e s r e d u c e i n c o m i n g l i g h t , p o t e n t i a l l y l i m i t i n g p h o t o s y n t h e s i s , and c o n s e q u e n t l y h e i g h t g r o w t h . T a l l s h o o t s under m o d e r a t e l y d ense c a n o p i e s w o u l d a l l o w f o r a g e t o be more a v a i l a b l e d u r i n g w i n t e r b e c a u s e s u c h c a n o p i e s i n t e r c e p t snow e f f e c t i v e l y ( B u n n e l l e t a l . 1985) and t a l l s h o o t s a r e l e s s l i k e l y t o be b u r i e d . The r e s u l t s i n d i c a t e t h a t s a l a l abundance i s r e l a t e d t o s t a n d c h a r a c t e r i s t i c s . I t i s d i f f i c u l t t o s a y , however, whether s a l a l f o r a g e would r e s p o n d t o t h i n n i n g i n agreement w i t h p r e d i c t i o n s made from t h e e q u a t i o n s i n t h i s s t u d y . S a l a l abundance e s t i m a t e s p r e d i c t e d f r o m t i m b e r i n v e n t o r y d a t a a r e p o s s i b l e f o r s i t e s w i t h c h a r a c t e r i s t i c s s i m i l a r t o t h o s e sampled h e r e (immature, u n t r e a t e d , s o u t h - s o u t h w e s t a s p e c t s , s p e c i f i c p l a n t a s s o c i a t i o n s ) . The method o f f o r e s t s a m p l i n g ( e . g . , p l o t o r p o i n t s a m p l e s ) w o u l d d e t e r m i n e w h i c h e q u a t i o n s t o u s e . I recommend u s i n g e i t h e r MCC o r SUMDIA b e c a u s e t e s t s o f e q u a t i o n s among v a r i a n t s were u n e q u i v o c a l and t h e s e two v a r i a b l e s had h i g h p r e d i c t a b i l i t i e s ( T a b l e s 2.2 and 2 . 3 ) . B e c a u s e r e l a t i o n s h i p s a r e c u r v i l i n e a r , s a l a l f o l i a r p r o d u c t i v i t y and f o l i a r b i o m a s s a r e a b o u t d o u b l e a t 65% MCC compared t o 80% MCC f c r c o m b i n e d d a t a e q u a t i o n s . The optimum t r a d e o f f between snow i n t e r c e p t i o n , s a l a l p r o d u c t i v i t y , and s h o o t h e i g h t may o c c u r a r o u n d 65-70% MCC. S a l a l c o n t r o l t h r o u g h s t a n d d e n s i t y management i s a l s o p o s s i b l e . S a l a l a b u n d a n c e s were a t a minimum i n p l o t s 1, 9, 11, and 26 h a v i n g R e i n e k e ' s (1933) s t a n d d e n s i t y i n d i c e s ( b a s e d on p l o t t r e e measurements) o f 974, 1335, 1243, and 1005, r e s p e c t i v e l y . S t a n d s h a v i n g SDI's g r e a t e r t h a n 1000 w o u l d p r o b a b l y have an a d v e r s e e f f e c t on s a l a l , a l t h o u g h s i t e e f f e c t s ( e . g . , m o i s t u r e regime o r s t e e p s l o p e s a l l o w i n g c o n s i d e r a b l e s i d e l i g h t i n g ) may s u p p o r t h i g h e r a b u n d a n c e s of s a l a l t h a n e x p e c t e d ( a s i n p l o t s 4, 13-15, and 23 w i t h p l o t SDI's o f 1201, 1388, 1544, 1397, and 1028, r e s p e c t i v e l y ) . T h e s e p l o t s , however, were i n f l u e n c e d by s i d e l i g h t i n g b e c a u s e t h e y were l o c a t e d i n d e n s e s t a n d p a t c h e s w i t h a r e l a t i v e l y open s t a n d o u t s i d e t h e p l o t (BAFSDI was c o n s i d e r a b l y l o w e r t h a n p l o t SDI f o r a l l o f t h e s e p l o t s ) . CONCLUSION The f u n c t i o n a l r e l a t i o n s h i p o f s a l a l d e n s i t y t o f o r e s t o v e r s t o r y c h a r a c t e r i s t i c s i s d i f f e r e n t i n t h e two p l a n t a s s o c i a t i o n s s t u d i e d , but t h e d i f f e r e n c e may be due t o age e f f e c t s . S i m p l e l i n e a r r e g r e s s i o n s w i t h o v e r s t o r y c h a r a c t e r i s t i c s as i n d e p e n d e n t v a r i a b l e s a c c o u n t e d f o r 90% o r more of t h e v a r i a t i o n i n s a l a l d e n s i t y among sample d p l o t s . The r e l a t i o n s h i p s o f s a l a l p r o d u c t i v i t y , b i o m a s s and c o v e r t o f o r e s t s t a n d c h a r a c t e r i s t i c s a r e not d i f f e r e n t between p l a n t a s s o c i a t i o n s . F o r c ombined d a t a and u s i n g i n d e p e n d e n t v a r i a b l e s o b t a i n e d from p l o t s a m p l e s , s i m p l e l i n e a r r e g r e s s i o n s a c c o u n t e d f o r 58-82% of v a r i a t i o n i n s a l a l b i o m a s s and c o v e r . M u l t i p l e r e g r e s s i o n s i n c l u d i n g crown d e p t h i m p r o v e d t h e p r e d i c t a b i l i t y o f t h e e q u a t i o n s . R e l a t i o n s h i p s d e v e l o p e d among s t a n d s o f d i f f e r e n t a g e s and l o c a t i o n s were more v a r i a b l e t h a n r e l a t i o n s h i p s d e v e l o p e d w i t h i n s t a n d s . R e l a t i o n s h i p s between s a l a l u n d e r s t o r y and f o r e s t o v e r s t o r y were g e n e r a l l y h y p e r b o l i c , but some e q u a t i o n s were l i n e a r . The b e s t f o r e s t s t a n d c h a r a c t e r i s t i c s t o use t o p r e d i c t s a l a l abundance a r e mean crown c o m p l e t e n e s s , sum o f t r e e d i a m e t e r s , o r s t a n d d e n s i t y i n d e x . S a l a l h e i g h t was g r e a t e s t between 65 and 80% MCC. A l t h o u g h mean s h o o t h e i g h t was l e s s i n t h e CWHb 3 v a r i a n t , t h e shape o f t h e r e l a t i o n s h i p was t h e same among t h e t h r e e v a r i a n t s s a m p l e d . 41 REFERENCES A l a b a c k , P.B. 1982. Dynamics o f u n d e r s t o r y b i o m a s s i n S i t k a s p r u c e - w e s t e r n hemlock f o r e s t s o f s o u t h e a s t A l a s k a . E c o l o g y . 63:1932-1948. A n d e r s o n , R . C , O.L. L o u c k s , and A.M. Swain. 1969. H e r b a c e o u s r e s p o n s e t o canopy c o v e r , l i g h t i n t e n s i t y , and t h r o u g h f a l l p r e c i p i t a t i o n i n c o n i f e r o u s f o r e s t s . E c o l o g y . 50:255-263. 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Morgan. 1981. The b a l a n c e between t h e f o l i a g e p r o j e c t i v e c o v e r s of o v e r s t o r e y and u n d e r s t o r e y 44 s t r a t a i n A u s t r a l i a n v e g e t a t i o n . A u s t . J . E c o l . 6:193-202. S t a n e k , W., D. Beddows, and D. S t a t e . 1979. F e r t i l i z a t i o n and t h i n n i n g e f f e c t s on a D o u g l a s - f i r e c o s y s t e m a t Shawnigan Lake on V a n c o u v e r I s l a n d . Can. F o r . S e r v . R e p t . BC-R-1. V i c t o r i a , B.C. Swank, W.T. 1972. Water b a l a n c e , i n t e r c e p t i o n , and t r a n s p i r a t i o n s t u d i e s on a w a t e r s h e d i n t h e Puget l o w l a n d r e g i o n o f w e s t e r n W a s h i n g t o n . Ph.D. t h e s i s . U n i v . o f W a s h i n g t o n , S e a t t l e , WA. Tan, C.S., T.A. B l a c k , and J.U. Nnyamah. 1977. C h a r a c t e r i s t i c s o f s t o m a t a l d i f f u s i o n r e s i s t a n c e i n a D o u g l a s - f i r f o r e s t e x p o s e d t o s o i l w a t e r d e f i c i t s . Can. J . F o r . Res. 7:595-604. T u r n e r , J . a n d J.N. L o n g . 1975. A c c u m u l a t i o n o f o r g a n i c m a t t e r i n a s e r i e s of D o u g l a s - f i r s t a n d s . Can. J . F o r . Res. 5:681-690. V a l e s , D . J . and F . L . B u n n e l l . 1985. C o m p a r i s o n of methods f o r e s t i m a t i n g f o r e s t o v e r s t o r y c o v e r . R e s e a r c h , M i n i s t r i e s of E n v i r o n m e n t and F o r e s t s . IWIFR-20. V i c t o r i a , B.C. V a l e s , D . J . , F . L . B u n n e l l , A. McLeod, and R.M. E l l i s , (in prep.). Biomass a l l o m e t r i c r e l a t i o n s h i p s o f s a l a l (Gaultheria shallon). W a t t s , S.B. ( e d . ) . 1983. F o r e s t r y handbook f o r B r i t i s h C o l u m b i a . F o r e s t r y U n d e r g r a d u a t e S o c i e t 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 , V a n c o u v e r , B.C. Weetman, G.F., A. G e r m a i n , and R. F o u r n i e r . 1986. F e r t i l i z e r s c r e e n i n g t r i a l s o f s t a g n a t e d S i t k a s p r u c e p l a n t a t i o n s on n o r t h e r n V a n c o u v e r I s l a n d , B.C. S o i l S c i . S o c . Am. J . ( s u b m i t t e d ) . W e l l n e r , C A . 1948. L i g h t i n t e n s i t y r e l a t e d t o s t a n d d e n s i t y i n m ature s t a n d s o f t h e w e s t e r n w h i t e p i n e t y p e . J . F o r . 46:16-19. Young, J.A., D.W. H e d r i c k , and R.F. K e n i s t o n . 1967. F o r e s t c o v e r and l o g g i n g - h e r b a g e and browse p r o d u c t i o n i n t h e mixed c o n i f e r o u s f o r e s t o f n o r t h e a s t e r n O r e g o n . J . F o r . 65:807-813. Z a v i t k o v s k i , J . 1976. Gr o u n d v e g e t a t i o n b i o m a s s , p r o d u c t i o n , and e f f i c i e n c y of e n e r g y u t i l i z a t i o n i n some n o r t h e r n W i s c o n s i n f o r e s t e c o s y s t e m s . E c o l o g y . 57:694-706. 45 CHAPTER 3. RELATIONSHIPS BETWEEN TRANSMISSION OF SOLAR RADIATION AND FOREST STAND CHARACTERISTICS INTRODUCTION T r a n s m i s s i o n o f s h o r t w a v e s o l a r r a d i a t i o n i n t o f o r e s t s t a n d s has been e v a l u a t e d e m p i r i c a l l y ( e . g . , W e l l n e r 1948; M i l l e r 1959; V e z i n a and P e c h 1964) and d i s c u s s e d o r modeled t h e o r e t i c a l l y ( e . g . , A n d e r s o n 1966; Cowan 1968; Lemeur 1973; Norman 1975; Norman and J a r v i s 1975; Ross 1981; B a l d o c c h i e t a l . 1985). S o l a r r a d i a t i o n u nder f o r e s t c a n o p i e s has been r e l a t e d t o snow m e l t ( e . g . , M i l l e r 1959), u n d e r s t o r y g r o w t h ( A n d e r s o n e t a l . 1969; Z a v i t k o v s k i 1976; C h a p t e r 4 ) , d e e r and e l k t h e r m a l c o v e r ( B u n n e l l e t a l . 1986), and p r o d u c t i o n e f f i c i e n c y ( e . g . , Z a v i t k o v s k i 1976). P r e d i c t i n g s o l a r r a d i a t i o n u nder f o r e s t c a n o p i e s c a n be done u s i n g s t a n d c h a r a c t e r i s t i c s ( e . g . , M i l l e r 1959; P e r r y e t a l . 1969) or w i t h h e m i s p h e r i c a l p h o t o g r a p h y ( E v a n s and Coombe 1959; A n d e r s o n 1964a; Madgwick and B r u m f i e l d 1969). H e m i s p h e r i c a l p h o t o g r a p h y has t h e a d v a n t a g e of b e i n g w i d e l y a p p l i c a b l e , but i s a f f e c t e d by e x p o s u r e c o n d i t i o n s . R e l a t i o n s h i p s between t r a n s m i s s i o n and s t a n d c h a r a c t e r i s t i c s among s i t e s may d i f f e r b e c a u s e of s t a n d s t r u c t u r e o r s p e c i e s c o m p o s i t i o n ( W e l l n e r 1948), o r methods o f s a m p l i n g p r e d i c t o r v a r i a b l e s ( B u n n e l l and V a l e s 1986). Crown c l o s u r e , b a s a l a r e a , number o f t r e e s , and s t a n d d e n s i t y (sum o f d i a m e t e r s ) have been t h e most common 46 p r e d i c t o r v a r i a b l e s . Some r e s e a r c h e r s have s t u d i e d t r a n s m i s s i o n o f s e p a r a t e r a d i a t i o n components i n t o f o r e s t s t a n d s ( e . g . , M u l l e r 1971; R e i f s n y d e r e t a l . 1971/72; H u t c h i s o n and M a t t 1977; B a l d o c c h i e t a l . 1984a, 1984b). A n d e r s o n (1964b) s t r e s s e d t h e i m p o r t a n c e o f a p p r o p r i a t e i n s t r u m e n t a t i o n , sample d e s i g n , and s e p a r a t i o n o f r a d i a t i o n components b e c a u s e e a c h a r e i n t e r c e p t e d d i f f e r e n t l y by t h e c a n o p y . R e i f s n y d e r e t a l . (1971/72) and Gay e t a l . (1971) d e m o n s t r a t e d t h e i m p o r t a n c e o f c o n s i d e r i n g t h e s p a t i a l v a r i a t i o n o f p e n e t r a t i o n o f r a d i a t i o n . T h i s s t u d y examined t h e p e n e t r a t i o n o f t h e g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e (measured a s p h o t o n f l u x d e n s i t y , PPFD, 0.4-0.7 jim) components of s o l a r r a d i a t i o n (0.3-3.0 p.m) i n t o immature c o n i f e r o u s f o r e s t s t a n d s on V a n c o u v e r I s l a n d , B r i t i s h C o l u m b i a . S p e c i f i c o b j e c t i v e s were t o : 1) d e v e l o p r e g r e s s i o n s p r e d i c t i n g t r a n s m i s s i o n o f s o l a r r a d i a t i o n components f r o m f o r e s t s t a n d c h a r a c t e r i s t i c s ; 2) d e t e r m i n e i f t h e r e l a t i o n s h i p s were d i f f e r e n t between s t a n d s of d i f f e r e n t s t r u c t u r e s ; and 3) a s s e s s t h e d e g r e e t o w h i c h t h e h e m i s p h e r i c a l p h o t o g r a p h method of A n d e r s o n (1964a) as a d a p t e d by V a l e s and B u n n e l l (1986) p r e d i c t s t r a n s m i s s i o n o f d i f f u s e , d i f f u s e PPFD, and d i r e c t r a d i a t i o n . 47 STUDY AREAS T w e l v e p l o t s were sampled a t s e v e r a l l o c a t i o n s on V a n c o u v e r I s l a n d , B r i t i s h C o l u m b i a , Canada. S i x p l o t s were i n t h e C o a s t a l W e s t e r n Hemlock d r y sub z o n e (CWHa; K r a j i n a 1965) and 6 were i n t h e CWH wet subzone (CWHb). The CWHa p l o t s were s e p a r a t e d g e o g r a p h i c a l l y and i n s t a n d s o f d i f f e r e n t a g e s and s t r u c t u r e s . CWHb p l o t s were a l l l o c a t e d i n t h e same s t a n d w i t h l e s s t h a n 800 m between t h e f a r t h e s t s e p a r a t e d p l o t s . The CWHb s t a n d was y o u n g e r , w i t h s m a l l e r t r e e s t h a n s t a n d s i n t h e CWHa ( T a b l e 3 . 1 ) . B e c a u se t h e two s u b z o n e s were r e p r e s e n t e d by s t a n d s w i t h b r o a d s t r u c t u r a l d i f f e r e n c e s , f u t u r e r e f e r e n c e s t o s u b z o n e s w i l l be synonymous w i t h s t r u c t u r a l d i f f e r e n c e s . A l l p l o t s were i n immature s t a n d s o f D o u g l a s - f i r (Pseudotsuga menziesii ( M i r b . ) F r a n c o ) , w e s t e r n hemlock (Tsuga het er ophylI a ( R a f . ) S a r g . ) , and w e s t e r n r e d c e d a r (Thuja pii cat a Donn). A d d i t i o n a l s p e c i e s f o u n d i n t h e CWHb s t a n d were a m a b i l i s f i r (Abies amabilis ( D o u g l . ) F o r b e s ) , y e l l o w - c e d a r (Chamaecypari s nookat ensi s (D. Don) S p a c h ) , and w e s t e r n w h i t e p i n e (Pinus monticola D o u g l . ) . P l o t s were s e l e c t e d t o encompass a r a n g e o f o v e r s t o r y c o v e r . C r i t e r i a u s e d t o l o c a t e p l o t s were: homogeneous canopy s t r u c t u r e , no d e c i d u o u s t r e e s , s t a n d age 30-60 y e a r s , no s t a n d t r e a t m e n t ( e . g . , no t h i n n i n g o r f e r t i l i z a t i o n ) , s l o p e s 10-60%, s o u t h - s o u t h w e s t a s p e c t s , and e l e v a t i o n 200-600 m. T A B L E 3 . 1 D e s c r i p t i o n s of p l o t s used to sample s o l a r r a d i a t i o n and f o r e s t s t a n d c h a r a c t e r i s t i c s P l o t L a t i tude- Longi tude Aspect C ) E l e v . (m) Slope (%) Age MCC a Spp. Comp^ DF-WH-MiSC NTREES C U/ha) BA C Avg. DBH C (m'/na) (mm) Avg. H t C (m) CRNDEP C (m) 1 d 5 0 ' 1 2 ' - 1 2 6 * 2 8 ' 2 3 0 4 3 0 3 0 2 8 0 . 9 1 2 8 - 7 2 - 0 2 5 3 3 3 7 . 7 1 3 1 1 2 . 4 9 . 4 2 d 5 0 ' 0 7 ' - 1 2 5 * 3 9 ' 2 1 5 2 7 0 1 5 3 7 0 . 7 8 6 1 - 2 3 - 0 1 6 0 0 4 6 . 7 1 7 3 1 3 . 6 1 0 . 1 4 8 ' 5 4 ' - 1 2 4 ' 1 8 ' 2 0 6 3 1 0 5 2 6 0 0 . 6 4 1 0 0 - o - 0 7 5 6 3 5 . 0 2 3 5 2 5 . 2 7 . 3 e d 4 8 ' 5 4 ' - 1 2 4 " 1 8 ' 2 1 5 3 1 0 4 5 5 9 0 . 7 8 1 0 0 - 0 - 0 1 7 3 3 3 4 . 4 1 4 5 1 5 . 6 5 . 8 7 d 4 8 ' 5 4 ' - 1 2 4 ' 1 8 ' 1 7 3 2 0 0 9 3 4 0 . 3 5 8 - 9 2 - 0 2 6 7 1 4 . 8 2 1 9 1 5 . 7 1 3 . 1 9 d 4 8 ' 4 9 ' - 1 2 4 ' 1 9 ' 2 6 1 6 3 0 4 3 4 2 0 . 9 0 3 7 - 6 2 - 1 2 7 1 1 5 4 . 9 1 4 9 1 5 . 0 7 . 9 2 1 s 4 8 ' 3 6 ' - 1 2 3 ' 5 2 ' 2 4 0 5 7 0 3 0 3 0 0 . 5 8 9 7 - 3 - 0 8 8 9 1 0 . 1 1 1 0 9 . 7 8 . 9 2 2 e 4 8 ' 3 6 ' - 1 2 3 ' 5 2 ' 2 4 0 5 7 0 3 0 3 0 0 . 4 2 1 0 0 - 0 - 0 7 5 6 8 . 5 1 1 8 1 0 . 3 9 . 8 2 3 e 4 8 ' 3 6 ' - 1 2 3 ' 5 2 ' 2 2 0 5 7 0 2 0 3 0 0 . 8 1 7 4 - 2 0 - 6 2 2 2 2 4 1 . 6 1 4 4 1 3 . 4 1 1 . 3 2 4 6 4 8 ' 3 6 ' - 1 2 3 ' 5 2 ' 2 2 0 5 7 0 2 0 3 0 0 . 6 4 6 4 - 1 1 - 2 5 1 1 1 1 2 6 . 1 1 5 9 1 4 . 3 1 2 . 8 2 6 S 4 8 ' 3 6 ' - 1 2 3 ' 5 2 ' 2 1 9 5 5 0 1 9 3 0 0 . 9 0 2 8 - 6 2 - 1 0 2 6 2 2 3 8 . 9 1 2 8 1 2 . 7 9 . 3 2 7 6 4 8 ' 3 6 ' - 1 2 3 ' 5 2 ' 2 1 4 6 0 0 2 2 3 0 0 . 7 6 5 2 - 3 0 - 1 8 1 3 7 8 1 7 . 5 1 1 9 1 1 . 5 8 . 7 Mean crown completeness e s t i m a t e of f o r e s t o v e r s t o r y c over. ^ P e r c e n t of s p e c i e s by ba s a l a r e a c o n t r i b u t i o n . D F = D o u g l a s - f i r , WH=western hemlock, Misc=other c o n i f e r o u s s p e c i e s . °Determined from t r e e s > 8 . 0 cm DBH. P l o t s i n CWHa subzone. e P l o t s i n CWHb subzone. oo 49 M E T H O D S Overstory sampling F o r e s t o v e r s t o r y c o v e r i s te r m e d "mean crown c o m p l e t e n e s s " (MCC) sensu B u n n e l l e t a l . (1985:181) and i s d e f i n e d t o i n c l u d e h o l e s w i t h i n a s w e l l a s between t r e e c r o w n s . P l o t s (9 x 25 m, 0.0225 ha) were l a i d o u t a l o n g s l o p e c o n t o u r s a nd MCC was s y s t e m a t i c a l l y s a m p l e d a t 52 p o i n t s w i t h i n e a c h p l o t u s i n g a 10° a r c moosehorn ( R o b i n s o n 1947; Bonnor 1967). The sample d e s i g n p r o v i d e d c o m p l e t e c o v e r a g e o f t h e c a n o p y above e a c h p l o t . Two d e s i g n s were u s e d t o sample a d d i t i o n a l s t a n d c h a r a c t e r i s t i c s . T r e e s p e c i e s , d i a m e t e r a t b r e a s t h e i g h t (DBH), t o p h e i g h t , and h e i g h t t o ba s e o f l i v e crown (HBLC; h e i g h t where l o w e s t l i v e b r a n c h e s were a t t a c h e d t o t h e b o l e ) were r e c o r d e d f o r a l l t r e e s > 8.0 cm DBH i n s i d e t h e p l o t . T r e e s < 8.0 cm DBH and > 20 cm t a l l were c o u n t e d . P o i n t s a m p l e s were t a k e n w i t h a 4 b a s a l a r e a f a c t o r (BAF„) p r i s m a t t h e f o u r p l o t c o r n e r s and a t p l o t c e n t e r . S p e c i e s and DBH of " i n " t r e e s were r e c o r d e d f o r t h e p r i s m s a m p l e s . Samples o f t r e e s o n l y i n t h e p l o t r e f l e c t p r o c e s s e s a c t i n g w i t h i n t h e p l o t . P r i s m samples i n c l u d e d t r e e s o u t s i d e t h e p l o t and i n t e g r a t e p r o c e s s e s a c t i n g w i t h i n a s w e l l a s from a n g l e s o u t s i d e t h e p l o t . P l o t o v e r s t o r y c h a r a c t e r i s t i c s a r e summarized i n T a b l e 3.1. F i v e h e m i s p h e r i c a l p h o t o g r a p h s were t a k e n w i t h i n e a c h p l o t and a n a l y z e d f o r d i f f u s e and d i r e c t s i t e f a c t o r s (sensu 50 A n d e r s o n 1964a) u s i n g t h e method d e s c r i b e d by V a l e s and B u n n e l l ( 1 9 8 6 ) . Solar radiation sampling S h o r t w a v e s o l a r r a d i a t i o n ( 0 . 3 - 3 . 0 um) was m o n i t o r e d w i t h p a i r e d Dome s o l a r i m e t e r s ( L i n t r o n i c L t d . ) r e c o r d e d on CR-21 d a t a l o g g e r s a s 3-minute a v e r a g e s o f samples t a k e n a t 1-minute i n t e r v a l s . Shadow bands ( H o r o w i t z 1969) s e p a r a t e d d i f f u s e f r o m g l o b a l r a d i a t i o n w i t h s e n s o r s mounted 1.5 m above g r o u n d and p a i r e d on e a c h s t a n d . I d e a l l y , Drummond's (1956) c o r r e c t i o n f a c t o r s h o u l d be a p p l i e d t o s e n s o r s o u t s i d e a f o r e s t and a d i f f e r e n t c o r r e c t i o n t e r m , d e v e l o p e d f o r under f o r e s t c a n o p i e s , s h o u l d be a p p l i e d t o t h e b e l o w - c a n o p y s e n s o r s . B e c a u s e a p p r o p r i a t e c o r r e c t i o n s f o r b e l o w - c a n o p y s e n s o r s have n o t been e x p l o r e d , and t h e same c o r r e c t i o n t e r m a p p l i e d t o b o t h open and ca n o p y s e n s o r s would n o t a f f e c t r e l a t i v e amounts o f r a d i a t i o n , no c o r r e c t i o n s were made t o d i f f u s e s e n s o r s . H u t c h i s o n and M a t t (1977) a r g u e d t h a t no c o r r e c t i o n t e r m s h o u l d be a p p l i e d t o d i f f u s e s e n s o r s b e c a u s e b e l o w - c a n o p y d i f f u s e r a d i a t i o n r e s u l t s from m u l t i p l e r e f l e c t i o n s a nd t r a n s m i s s i o n t h r o u g h l e a v e s , and t h a t t h e d i s t r i b u t i o n o f b r i g h t n e s s under a canopy i s d i f f e r e n t f r o m t h a t a b o v e . One p a i r o f s e n s o r s r e c o r d e d s o l a r r a d i a t i o n i n an open a r e a n e a r t h e p l o t t o d e t e r m i n e t h e amount o f r a d i a t i o n p o t e n t i a l l y a bove t h e c a n o p y . Two p a i r s of s e n s o r s were l o c a t e d 11 m a p a r t w i t h i n p l o t s , a l o n g t h e c e n t e r l i n e , a nd 7 m 51 i n from e a c h edge. One LI-COR LI-190SB quantum s e n s o r was s h a d e d and m o n i t o r e d d i f f u s e p h o t o s y n t h e t i c p h o t o n f l u x d e n s i t y r a d i a t i o n (PPFD; 0.4-0.7 nm) i n t h e p l o t c e n t e r as 3-minute a v e r a g e s of 1-minute s a m p l e s . The Dome s o l a r i m e t e r s were c a l i b r a t e d a g a i n s t a r e f e r e n c e K i p p & Zonen s o l a r i m e t e r . C a l i b r a t i o n s were c u r v i l i n e a r o v e r t h e e n t i r e r a n g e (Matt and H u t c h i s o n 1974 c i t e d i n H u t c h i s o n and M a t t 1977). A l i n e a r c a l i b r a t i o n b a s e d on d a t a l e s s t h a n 150 W-nr 2 was a p p l i e d t o a l l d i f f u s e s e n s o r s b e c a u s e d i f f u s e r a d i a t i o n r a r e l y e x c e e d e d 150 W«irr 2. Had t h e f u l l - r a n g e c a l i b r a t i o n been a p p l i e d , t h e amount of d i f f u s e r a d i a t i o n w o uld have been o v e r e s t i m a t e d . The open d i f f u s e s o l a r i m e t e r was c a l i b r a t e d a g a i n s t t h e quantum s e n s o r t o o b t a i n an e q u a t i o n p r e d i c t i n g d i f f u s e PPFD above t h e c a n o p y . The r e s u l t s o f t h e c a l i b r a t i o n i n d i c a t e d t h a t 65% o f d i f f u s e s h o r t w a v e i r r a d i a n c e was i n t h e 0.4-0.7 nm waveband on an e n e r g y f l u x b a s i s ( u s i n g 4.24 ME/J o f McCree 1972 and M c C a r t n e y 1978 t o c o n v e r t t o J i n t h e p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n waveband), o r t h e r e was 2.756 juE o f p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n p h o t o n s p e r J o f d i f f u s e s h o r t w a v e s o l a r r a d i a t i o n . T h e s e v a l u e s a r e i n a greement w i t h Ross ( 1 9 7 5 ) , b u t a r e l o w e r t h a n t h o s e o f S z e i c z ( 1 9 7 4 ) . B e l o w - c a n o p y d i f f u s e r a d i a t i o n i s composed o f d i f f u s e r a d i a t i o n f r o m t h e sky t r a n s m i t t e d t h r o u g h t h e c a n o p y , r e f l e c t e d d i f f u s e , and s c a t t e r e d d i r e c t beam r a d i a t i o n ( R e i f s n y d e r e t a l . 1971/72). The p r o p o r t i o n of d i f f u s e r a d i a t i o n t r a n s m i t t e d t h a t was m e a s u r e d i n c l u d e d a l l t h r e e components and i s n o t t h e t r u e f r a c t i o n of a b o v e - c a n o p y d i f f u s e s k y r a d i a t i o n t h a t was t r a n s m i t t e d . D i r e c t r a d i a t i o n was o b t a i n e d by s u b t r a c t i n g t h e d i f f u s e r a d i a t i o n component from g l o b a l r a d i a t i o n . T r a n s m i s s i o n o f e a c h component was computed by d i v i d i n g t h e a v e r a g e d a i l y sum of t h e two be l o w - c a n o p y s e n s o r s by t h e d a i l y sum o f open r a d i a t i o n . D i f f e r e n c e s between d i f f u s e s e n s o r s under t h e ca n o p y were c o n s i s t e n t among p l o t s i n d i c a t i n g l i t t l e s p a t i a l v a r i a t i o n o f d i f f u s e r a d i a t i o n under c a n o p i e s . D i f f e r e n c e s between g l o b a l s e n s o r s were v a r i a b l e among p l o t s and d e m o n s t r a t e d t h e s p a t i a l v a r i a t i o n due t o s u n f l e c k s . O n l y d a y s t h a t were c l e a r o r m o s t l y sunny were u s e d f o r a n a l y s e s ( r a t i o open d i f f u s e / o p e n g l o b a l < 0.20). E a c h p l o t was m o n i t o r e d f o r a t l e a s t one f u l l d a y . Be c a u s e v a r i a b l e w e a t h e r c o n d i t i o n s d i d n o t a l w a y s p e r m i t m o n i t o r i n g a p l o t d u r i n g one f u l l c l e a r day, h a l f - d a y ( s u n r i s e t o s o l a r noon) m o n i t o r i n g was m u l t i p l i e d by 2 f o r two c a s e s . T r a n s m i s s i o n was a v e r a g e d f o r p l o t s s a m p l e d o v e r two d a y s . Definition of variables GLOBAL DIRECT DIFFUSE PAR MCC SUMDIA BA DBH g NTREES p r o p o r t i o n of g l o b a l s o l a r r a d i a t i o n t r a n s m i t t e d p r o p o r t i o n of d i r e c t s o l a r r a d i a t i o n t r a n s m i t t e d p r o p o r t i o n o f d i f f u s e s o l a r r a d i a t i o n t r a n s m i t t e d ( i n c l u d e d downward s c a t t e r i n g o f d i r e c t beam i n t r e e c a n o p i e s ) p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n a s a p r o p o r t i o n of d i f f u s e PPFD t r a n s m i t t e d mean crown c o m p l e t e n e s s ( a v e r a g e o f 52 moosehorn samples and r e p o r t e d a s a f r a c t i o n ) sum o f DBH (mm/225 m 2) o f p l o t t r e e s £ 8.0 cm b a s a l a r e a ( m 2 « h a " 1 ) o f p l o t t r e e s ^ 8.0 cm d i a m e t e r o f t r e e o f a v e r a g e b a s a l a r e a ( q u a d r a t i c mean d i a m e t e r ) number o f p l o t t r e e s « h a ~ 1 ^ 8.0 cm 53 SDI - R e i n e k e ' s " s t a n d d e n s i t y i n d e x " ( R e i n e k e 1933) computed f r o m : SDI = NTREES•(DBH / 2 5 ) 1 • 6 (Long 1985) q BAFBA - a v e r a g e s t a n d b a s a l a r e a ( m 2'ha" 1) o f t r e e s £ 8.0 cm d e t e r m i n e d from 5 B A F 4 p r i s m samples BAFTREES- a v e r a g e number of t r e e s - h a " " 1 £ 8.0 cm d e t e r m i n e d f r o m 5 BAF a p r i s m s a m p l e s BAFSDI - R e i n e k e ' s SDI d e t e r m i n e d from p r i s m s a m p l i n g computed from B A F T R E E S * ( B A F D B H g / 2 5 ) 1 • 6 Anal ys e s The p r o p o r t i o n t r a n s m i t t e d o f e a c h r a d i a t i o n component was r e g r e s s e d a g a i n s t s t a n d c h a r a c t e r i s t i c s u s i n g s i m p l e — h V — h V l i n e a r , s e c o n d - d e g r e e p o l y n o m i a l , a n d n o n l i n e a r (e , ae ) r e g r e s s i o n s . I n d e p e n d e n t v a r i a b l e s were e i t h e r u n t r a n s f o r m e d , n a t u r a l l o g , o r r e c i p r o c a l l y t r a n s f o r m e d . The b e s t r e g r e s s i o n s were i d e n t i f i e d a s h a v i n g t h e l o w e s t s t a n d a r d e r r o r o f t h e e s t i m a t e (sy.x)r w i t h a h i g h r2 ( i 2 i n t h e n o n l i n e a r r e g r e s s i o n s , E z e k i e l and Fox 1970), and no t r e n d i n t h e r e s i d u a l s . F o r a g i v e n d e p e n d e n t v a r i a b l e , t h e b e s t form o f r e g r e s s i o n f o r one i n d e p e n d e n t v a r i a b l e was n o t n e c e s s a r i l y t h e b e s t form f o r a d i f f e r e n t i n d e p e n d e n t v a r i a b l e . R a d i a t i o n components a l s o d i f f e r e d i n t h e b e s t forms of r e g r e s s i o n s w i t h d i r e c t and g l o b a l r a d i a t i o n r e g r e s s i o n s b e i n g d i f f e r e n t from d i f f u s e r e g r e s s i o n s . — h V G e n e r a l l y t h e n o n l i n e a r ae form was r a n k e d t h e b e s t f o r m o f r e g r e s s i o n f o r a l l r a d i a t i o n components a c r o s s a l l i n d e p e n d e n t v a r i a b l e s i n t h e s e p a r a t e s u b z o n e s . T h i s f o r m d o e s n o t d e p a r t g r e a t l y from B e e r ' s law p r e s e n t e d by M o n s i and - kz S a e k i ( 1 9 5 3 ) , e , w i t h s t a n d c h a r a c t e r i s t i c s b e i n g 54 c o r r e l a t e s o f z, c u m u l a t i v e l e a f a r e a i n d e x ( L A I ) . I a l s o — h V u s e d t h e e form t o e x p l o r e how r a d i a t i o n components may be i n t e r c e p t e d by s t a n d c h a r a c t e r i s t i c s . The ae form would g i v e an u n r e a l i s t i c e s t i m a t e i n open a r e a s w i t h an a c o e f f i c i e n t o t h e r t h a n 1.0. T e s t s of e q u a l r e g r e s s i o n s l o p e s and e q u a t i o n s between s u b z o n e s were computed w i t h c o v a r i a n c e a n a l y s i s u s i n g t h e UBC SLTEST p r o g r a m (Le 1971). T e s t s were made on l i n e a r forms u s i n g l o g and r e c i p r o c a l l y t r a n s f o r m e d i n d e p e n d e n t v a r i a b l e s b e c a u s e t h e s e forms o f r e g r e s s i o n s u s u a l l y had o n l y m o d e s t l y l a r g e r 5 's t h a n t h e ae f o r m , and b e c a u s e t e s t s were n o t a v a i l a b l e f o r t h e n o n l i n e a r f o r m . R e g r e s s i o n s d e v e l o p e d i n i n d i v i d u a l s u b z o n e s a r e p r e s e n t e d f o r a l l r a d i a t i o n components and f o r combined d a t a of GLOBAL, DIRECT, and PAR. T h i s manner o f p r e s e n t a t i o n i l l u s t r a t e s t h e r e l a t i o n s h i p among s t a n d s (CWHa) compared t o w i t h i n a s t a n d (CWHb) and t h e s t r e n g t h of t h e r e l a t i o n s h i p when a l l a r e c o m b i n e d . P a i r e d t - t e s t s w i t h i n s u b z o n e s and a c r o s s a l l p l o t s were u s e d t o t e s t t h e d i f f u s e and d i r e c t s i t e f a c t o r s e s t i m a t e d from h e m i s p h e r i c a l p h o t o g r a p h s a g a i n s t m e asured DIFFUSE, PAR, and DIRECT. D a t a m a n i p u l a t i o n and some a n a l y s e s were done u s i n g MIDAS (Fox and G u i r e 1976). A FORTRAN p r o g r a m w i t h a d e r i v a t i v e - f r e e , p a r a m e t e r - e s t i m a t i n g n o n l i n e a r r e g r e s s i o n s u b r o u t i n e (Moore 1984) computed n o n l i n e a r r e g r e s s i o n s , s ' s , and / 2 ' s . y x ' 55 R E S U L T S A N D D I S C U S S I O N Proportions transmitted D a i l y r a d i a t i o n l o a d s i n t h e open and below t h e canopy a r e summarized ( T a b l e 3 . 2 ) . Open g l o b a l s h o r t w a v e r a d i a t i o n r a n g e d f r o m 22 t o 29 MJ^m" 2^" 1 and open d i f f u s e was 7 t o 15% of t h e t o t a l . B e low-canopy f l u x e s depended upon o p e n n e s s o f th e p l o t . D i f f u s e r a d i a t i o n below t h e canopy r a n g e d from 18 t o 91% ( p l o t s 7 and 23, r e s p e c t i v e l y ) of g l o b a l . H a r d y (1975) f o u n d b e l o w - c a n o p y d i f f u s e t o be 36% of t h e t o t a l i n a 10-m t a l l 21 y e a r - o l d D o u g l a s - f i r s t a n d . Gay e t a l . (1971) r e p o r t e d an i n c r e a s e o f t h e d i f f u s e / g l o b a l r a t i o f r o m 15% above t o 46% below a Pinus taeda L . c a n o p y . The i n c r e a s e i n p r o p o r t i o n of be l o w - c a n o p y d i f f u s e i s due t o r e f l e c t i o n and s c a t t e r i n g o f d i r e c t beam r a d i a t i o n ( H u t c h i s o n and M a t t 1976). The amount o f d i f f u s e p h o t s y n t h e t i c a l l y a c t i v e r a d i a n t e n e r g y i n b e l o w - c a n o p y d i f f u s e s h o r t w a v e r a d i a t i o n was e s t i m a t e d r o u g h l y a t 2-24% by a s s u m i n g 4.24 M E / J f o r c o n v e r s i o n , or was 0.1-1.02 M E / J PPFD t o d i f f u s e s h o r t w a v e s o l a r i r r a d i a n c e ( T a b l e 3 . 2 ) . B a l d o c c h i e t a l . (1984a) f o u n d r a t i o s of b e l o w - c a n o p y g l o b a l p h o t o s y n t h e t i c a l l y a c t i v e r a d i a n t e n e r g y t o g l o b a l s h o r t w a v e between 22 and 29% i n a hardwood f o r e s t . A b s o r p t i o n o f PPFD by t h e ca n o p y was e v i d e n t by t h e d e c r e a s e d p r o p o r t i o n o f d i f f u s e PPFD i n d i f f u s e s h o r t w a v e r a d i a t i o n below t h e canopy compared t o t h e open ( T a b l e 3 . 2 ) . V a r i a b i l i t y i n t h e r a t i o of d i f f u s e PPFD t o d i f f u s e s h o r t w a v e e n e r g y f l u x was a s s o c i a t e d w i t h s t a n d s t r u c t u r e . TABLE 3.2 Daily sums of solar radiation components by plot Open radiation Canopy radiation Noon solar Plot Date a l t i t u d e Global Diffuse Direct PPFD3 D i f / G b G l o b a l 0 D i f f u s e 0 Direct PPFD3 PPFD/Dif d C ) (Md • m -»-day " ' ) (Enr *d-') (Md • nr -*-day- 1 ) (Em ) 1 e 22-23/7/84 60 28 .97 3 .08 25 .89 8 .50 0 . 106 0 . 763 0 . 546 0 .217 0 .084 0 . 153 2 1/8/84 58 25 .97 1 .79 24 . 19 4 .92 0 .069 1 .931 0, .644 1 . 288 0, . 244 0, .379 5 f 19-20/8/84 54 22 .44 3 .27 19 . 18 9 .00 0 . 146 1 .642 0. . 750 0, .892 0, .632 0, .810 6 22/8/84 53 23 .00 3 .31 19 .69 9 . 12 0. . 144 2. .082 0. .946 1 . 136 0, . 799 0. .845 1/9/84 50 21 .99 2 .31 19 .68 6 . 37 0. . 105 10 . 230 1 . 793 8 . 437 1 . 823 1. 017 9 e 3-4/7/85 64 27. .48 2 .51 24 .97 6 .92 0. .091 1 . 112 0. . 776 0. . 336 0. 079 0. 102 21 13/7/85 63 27. .82 3. . 19 24. .63 8 .80 0. .115 7 . 701 4 . 562 3. . 139 2. ,295 0. 503 22 17/7/85 63 26. .97 2. .94 24. .03 8 .09 0. . 109 15 . 279 5 . 283 9. ,995 1 . 750 0. 331 23 e 19-20/7/85 62 27. ,50 2 . 57 24 , 93 7 .08 0. 094 1 . 598 1 . 462 0. 136 0. 257 0. 176 24 26/7/85 61 26 . 91 2 . 42 24 . 49 6 .66 0. 090 3. , 644 2 . 785 0. 859 0. 747 0. 268 26 15/8/85 56 26. . 13 2. .34 23. .79 6 .44 0. 089 0. 908 0. 791 0. 117 0. 106 0. 134 27 17/8/85 55 25. 48 2 . 09 23. 39 5 .76 0. 082 3 . 614 2 . 704 0. 911 0. 462 0. 171 a D i f f u s e photosynthetic photon flux density. Ratio open diffuse/global as an index of clear sky, < 0.20 considered as sunny. Average of two sensors. dBelow-canopy r a t i o of photosynthetic photon flux density to below-canopy d i f f u s e solar irradiance (j,E-d~'). Average of monitoring two days. ^Computed from monitoring one f u l l day and one half-day x 2. ^Computed from monitoring one half-day x 2. T h e r e were s i g n i f i c a n t (p < 0.05, n = 12) n e g a t i v e c o r r e l a t i o n s between t h e b e l o w - c a n o p y r a t i o o f P P F D / d i f f u s e and s t a n d c h a r a c t e r i s t i c s (MCC, SUMDIA, BA, NTREES). B a l d o c c h i e t a l . (1986) f o u n d v a r i a t i o n i n t h e b e l o w - c a n o p y r a t i o o f g l o b a l p h o t o s y n t h e t i c a l l y a c t i v e r a d i a n t e n e r g y / g l o b a l s h o r t w a v e e n e r g y w i t h c h a n g e s i n s o l a r a l t i t u d e w i t h i n a s i n g l e s t a n d . Ranges o f p r o p o r t i o n s o f r a d i a t i o n t r a n s m i t t e d by t h e f o r e s t c a n o p y were 0.03 t o 0.57 f o r GLOBAL ( p l o t s 1 and 22, r e s p e c t i v e l y ) , 0.005 t o 0.43 f o r DIRECT ( p l o t s 26 and 7 ) , and 0.01 t o 0.29 f o r PAR ( p l o t s 1 and 7 ) . The p r o p o r t i o n o f d i f f u s e s h o r t w a v e r a d i a t i o n t r a n s m i t t e d d i f f e r e d d r a m a t i c a l l y between t h e two s t a n d s t r u c t u r e s . The p r o p o r t i o n o f d i f f u s e r a d i a t i o n t r a n s m i t t e d by CWHa p l o t s was 0.18 t o 0.78, but t h e p r o p o r t i o n t r a n s m i t t e d by CWHb p l o t s was 0.34 t o 1.80. The b a s e s o f t r e e crowns i n t h e CWHa were h i g h e r t h a n i n t h e CWHb s t a n d and HBLC was above t h e s e n s o r s i n t h e CWHa. S e n s o r s were l o c a t e d w i t h i n t r e e crowns i n t h e CWHb p l o t s (crowns e x t e n d e d n e a r l y t o t h e gro u n d ) and r e c o r d e d r e f l e c t e d d i r e c t beam r a d i a t i o n o c c u r r i n g w i t h i n t r e e c r o w n s . M i l l e r (1967, 1969) r e p o r t e d h i g h e r e s t i m a t e s of d i f f u s e and g l o b a l s o l a r r a d i a t i o n i n t h e upper p o r t i o n s o f Populous tremuloides M i c h x . and Quercus gambel i i N u t t . c a n o p i e s t h a n above t h e c a n o p y . M u l l e r (1971) a l s o r e p o r t e d s e v e r a l c a s e s where b e l o w - c a n o p y g l o b a l i r r a d i a n c e e x c e e d e d t h e i r r a d i a n c e i n t h e open. Hardy (1975) f o u n d t h a t 73% and 31% o f d i f f u s e s o l a r r a d i a t i o n was t r a n s m i t t e d t o t h e 5 m and g r o u n d l e v e l s i n a 1 0 m t a l l 58 u n t h i n n e d D o u g l a s - f i r s t a n d . F i g u r e 3.1 i l l u s t r a t e s a t i m e p l o t o f open and canopy g l o b a l and d i f f u s e r a d i a t i o n f o r p l o t 27 ( p r o p o r t i o n of d i f f u s e t r a n s m i t t e d 1.29). Canopy d i f f u s e and g l o b a l a r e much l e s s t h a n open g l o b a l and s u n f l e c k s a r e e v i d e n t a s p e a k s i n t h e b e l o w - c a n o p y g l o b a l c u r v e . The b e l o w - c a n o p y d i f f u s e c u r v e r i s e s above t h e open d i f f u s e c u r v e . Radiation-forest stand relationships R e s u l t s o f t h e r e g r e s s i o n s of r a d i a t i o n on s t a n d c h a r a c t e r i s t i c s f o u n d MCC, p l o t SUMDIA and SDI, and BAFSDI o b t a i n e d f r o m p r i s m s a m p l i n g t o be t h e b e s t v a r i a b l e s p r e d i c t i n g t r a n s m i s s i o n o f s o l a r r a d i a t i o n ( T a b l e 3 . 3 ) . Number o f t r e e s and b a s a l a r e a d e r i v e d f r o m p l o t t r e e measurements a l s o were a c c e p t a b l e p r e d i c t o r s . B a s a l a r e a d e r i v e d f r o m p r i s m s a m p l e s was p o o r e r t h a n u s i n g p l o t BA and t h e r e g r e s s i o n s d e v e l o p e d on number of t r e e s d e t e r m i n e d by p r i s m samples were n o t s i g n i f i c a n t . R e g r e s s i o n s t h a t i n c l u d e d number of s a p l i n g s ( t r e e s < 8.0 cm DBH and > 20 cm t a l l ) w i t h l a r g e r t r e e s were worse t h a n t h o s e u s i n g l a r g e r t r e e s a l o n e . S t a n d v a r i a b l e s r e p r e s e n t i n g t h e m i d s t o r y (number o f s a p l i n g s ) , t r e e d i a m e t e r , s p e c i e s c o m p o s i t i o n , h e i g h t , and crown d e p t h were p o o r s i n g l e p r e d i c t o r s o f t r a n s m i s s i o n . O t h e r s t u d i e s have not r e p o r t e d r e l a t i o n s h i p s w i t h SDI as an i n d e p e n d e n t v a r i a b l e . SDI i n t e g r a t e s t r e e s i z e , b a s a l a r e a , and number o f t r e e s and s h o u l d be a u s e f u l i n t e g r a t o r o f t r e e f o l i a g e and s t a n d d e n s i t y . 1 0 0 0 - 1 0 4 0 0 0 8 0 0 1 2 0 0 1 6 0 0 2 0 0 0 TRUE SOLAR TIME F i g u r e 3.1. S o l a r i r r a d i a n c e as a f u n c t i o n o f t i m e f o r p l o t 27. Open g l o b a l (•) and d i f f u s e ( • • • • • • • ) , c a n o p y g l o b a l (o) and d i f f u s e ( • ) . T A B L E 3.3 Regression c o e f f i c i e n t s of equations p r e d i c t i n g solar r a d i a t i o n components from f o r e s t stand c h a r a c t e r i s t i c s . Sample s i z e s : CWHa=6, CWHb=6. Equations s i g n i f i c a n t at p £ 0.05. Regression equation: Y «= ae Y Subzone X a b / 2 5 yx GLOBAL: CWHa MCC 2.4109 4.7957 0.98 0.0282 SUMDIA 0.8657 4.8273E-4 0 0.96 0.0363 SDI 1.2643 3.4154E-3 0.97 0.0324 BAFSDI 6.8557 6.2906E-3 0.96 0.0364 CWHb MCC 4.8879 5.1702 0.97 0.0366 SUMDIA 1.9707 7.2250E-4 0.85 0.0867 SDI 1.4843 4.8465E-3 0.86 0.0830 BAFSDI 1.5890 4.5990E-3 0.96 0.0449 Both MCC 2.3547 4.1668 0.86 0.0701 SUMDIA 0.9792 4.7260E-4 0.85 0,0725 SDI 1.1656 3.7187E-3 0.88 0.0654 BAFSDI 1.3514 3.7443E-3 0.84 0.0761 DIFFUSE: CWHa MCC 1 .5923 2.1929 0.85 0.0917 SUMDIA 0.9120 1.8875E-4 0.72 0.1255 SDI 1.1061 1.4430E-3 0.70 0.1292 BAFSDI N.S.6 0.46 0.1732 CWHb MCC SUMDIA SDI BAFSDI 4.8886 2.6581 2.4254 2.8328 2.2770 2.2341E-4 1.4755E-3 1.8436E-3 0.78 0.94 0.92 0.84 0.2848 0.1519 0.1763 0.2435 CWHa MCC 3.3782 6.0002 0. 98 0. 0226 SUMDIA 0.9725 6.2694E-4 0. 98 0. 0283 SDI 1.5134 4.2891E-3 0. 98 0. 0245 BAFSDI 12.0179 7.7863E-3 0. 98 0. 0256 CWHb MCC 14.2767 8.4899 0. 99 0. 0202 SUMDIA 1 .0 6.6399E-4 0. 70 0. 0970 SDI 1.0 5.3104E-3 0. 77 0. 0851 BAFSDI 1.0 4.8240E-3 0. 86 0. 0659 Both MCC 3.6343 5.8766 0. 93 0. 0432 SUMDIA 1.2592 7.7261E-4 0. 85 0. 0623 SDI 1 .5885 6.0770E-3 0. 74 0. 0812 BAFSDI 1.1168 4.3206E-3 0. 63 0. 0972 PAR: CWHa CWHb Both MCC 1 . 1995 4. 1655 0. 95 0. 0253 SUMDIA 0. 4763 3. 9642E-4 0. 95 0. 0251 SDI 0. 6697 2. 8915E-3 0. 96 0. 0237 BAFSDI 2. 621 1 5. 1752E-3 0. 95 0. 0253 MCC 0. 9428 3. 1579 0. 67 0. 0635 SUMDIA 0. 6171 4. 6447E-4 0. 92 0. 0302 SDI 0. 4694 2. 8252E-3 0. 88 0. 0384 BAFSDI 0. 5200 2. 9551E-3 0. 84 0. 0447 MCC 0. 9927 3. 4685 0. 79 0. 0473 SUMDIA 0. 5100 4. 0491E-4 0. 93 0. 0264 SDI 0. 4930 2. 6627E-3 0. 87 0. 0367 BAFSDI 0. 5551 2. 8154E-3 0. 74 0. 0522 "Exponent for power of .10. ^Equation not s i g n i f i c a n t (p > 0.05). 61 Some of t h e e q u a t i o n s ( e . g . , DIRECT v e r s u s SUMDIA, SDI i n t h e CWHb) gave p e c u l i a r r e s u l t s when e x t r a p o l a t e d o u t s i d e t h e — A Y r a n g e o f t h e d a t a u s i n g t h e ae f o r m . T h e s e e q u a t i o n s were — h V r e c a l c u l a t e d a s e and a r e p r e s e n t e d i n T a b l e 3.3 w i t h an i n t e r c e p t o f 1.0. The e q u a t i o n s p r e s e n t e d a r e a p p l i c a b l e o n l y w i t h i n t h e r a n g e of t h e s t a n d d a t a u s e d t o d e v e l o p them. The n e g a t i v e e x p o n e n t i a l r e l a t i o n s h i p s ( e q u a t i o n s from T a b l e 3.3) a r e i l l u s t r a t e d i n F i g . 3.2 as a f u n c t i o n o f MCC. S o l i d l i n e s f o r DIFFUSE r e p r e s e n t e q u a t i o n s d e v e l o p e d i n i n d i v i d u a l s u b z o n e s . D o t t e d c u r v e s i n F i g . 3.2 f o r GLOBAL, DIRECT and PAR r e p r e s e n t t h e r e l a t i o n s h i p s d e v e l o p e d i n i n d i v i d u a l s u b z o n e s and t h e s o l i d l i n e i s f o r c o m b i n e d d a t a . The d a s h e d l i n e i n t h e g l o b a l g r a p h i s r e p r o d u c e d from M i l l e r (1959) and i s a g e n e r a l r e l a t i o n s h i p d e r i v e d from t h e r e s u l t s of s e v e r a l s t u d i e s i n Pinus spp. s t a n d s i n w h i c h v a r i o u s methods were u s e d t o e s t i m a t e crown c l o s u r e . V e z i n a and P e ch (1964) p r e s e n t e d a r e l a t i o n s h i p p r e d i c t i n g t r a n s m i s s i o n from crown c l o s u r e e s t i m a t e d w i t h a moosehorn i n Pinus banksi ana Lamb, s t a n d s t h a t was a l s o h i g h e r t h a n t h a t of M i l l e r ( 1 9 5 9 ) . D i f f e r e n c e s i n t h e c u r v e s may be r e l a t e d t o d i f f e r e n t methods u s e d t o sample r a d i a t i o n ( A n d e r s o n 1964b), s t a n d s t r u c t u r e o r s p e c i e s c o m p o s i t i o n ( W e l l n e r 1948), o r d i f f e r e n c e s i n methods u s e d t o e s t i m a t e f o r e s t o v e r s t o r y c o v e r ( B u n n e l l and V a l e s 1986). I n d i c e s o f d e t e r m i n a t i o n (/', a n a l a g o u s t o r2) were computed f o r s e v e n i n d e p e n d e n t v a r i a b l e s p r e d i c t i n g r a d i a t i o n — h V components u s i n g t h e r e g r e s s i o n f o r m e ( T a b l e 3 . 4 ) . T h i s 62 < oo 2 0.6 0.4 2 0 2 o 0.0 0.6-1 UJ gc Q Z o g 2 o C — i — i — i — i — i — i — i 0.3 0.4 0.6 0.6 0.7 0.8 0.9 1.0 - i 1 1 1 r — r 1 0.3 0.4 0.6 0.6 0.7 0.8 0.9 1.0 2.0-1 0.0-1 1 1 1 1 1 1 1 0.3 0.4 0.6 0.6 0.7 0.8 0.9 t.O MEAN CROWN COMPLETENESS o - i 1 1 1 1 1 1 1 0.3 0.4 0.6 0.6 0.7 0.8 0.9 1.0 MEAN CROWN COMPLETENESS F i g u r e 3.2. R e l a t i o n s h i p s between t h e p r o p o r t i o n s o f s o l a r r a d i a t i o n components t r a n s m i t t e d and mean crown c o m p l e t e n e s s . D o t t e d l i n e s i n a, b, and d a r e r e l a t i o n s h i p s f o r i n d i v i d u a l s u b z o n e s . Dashed l i n e i n a i s from M i l l e r ( 1 9 5 9 ) . CWHa (•), CWHb (ffl). 63 TABLE 3.4 I n d i c e s o f d e t e r m i n a t i o n (/*) f r o m r e g r e s s i o n s p r e d i c t i n g r a d i a t i o n components f r o m f o r e s t s t a n d c h a r a c t e r i s t i c s u s i n g t h e r e g r e s s i o n f o r m Y = e X G l o b a l D i r e c t D i f f u s e PAR Avg. rank* 3 CWHa: MCC 0.854 0.836 0.736 0.945 3.0 SUMDIA 0.951 0.975 0.707 0.791 2.8 NTREES 0.892 0.946 0.414 0.779 5.0 BA 0.913 0.906 0.647 0.941 3.3 SDI 0.955 0.954 0.694 0.910 2.3 BAFBA 0.706 0.698 0.427 0.821 5.5 BAFSDI 0.696 0.685 0.393 0.863 6.3 CWHb: MCC 0.689 0.663 0.010 0.666 6.0* SUMDIA 0.802 0.702 0.021 0.882 3.7 NTREES 0.751 0.659 0.007 0.876 5.0 BA 0.834 0.779 0.034 0.678 3.7 SDI 0.842 0.771 0.030 0.738 3.3 BAFBA 0.909 0.865 0.010 0.599 3.3 BAFSDI 0.910 0.863 0.010 0.653 3.0 Combined: MCC 0.729 0.751 0. 142 0.787 4.0* SUMDIA 0.850 0.841 0.300 0.766 2.3 NTREES 0.534 0.646 0.221 0.086 6.0 BA 0.789 0.569 0.369 0.504 4.0 SDI 0.874 0.733 0.345 0.742 2.3 BAFBA 0.770 0.547 0.312 0.416 5.3 BAFSDI 0.809 0.631 0.280 0.600 4.3 flAverage ^ E x c l u d e s r a n k o f s d i f f u s e a c r o s s yx r a d i a t i o n components: r a n k . 1=lowest, 6 = h i g h e s t . 64 f o r m has a r e g r e s s i o n i n t e r c e p t o f 1 and c o m p a r i s o n o f T a b l e s 3.3 and 3.4 i n d i c a t e s t h e i m p o r t a n c e of t h e e q u a t i o n i n t e r c e p t s i n T a b l e 3.3. The e fo r m w o u l d be more a p p l i c a b l e o u t s i d e t h e ran g e o f t h e d a t a and g i v e a r e a l i s t i c e s t i m a t e o f t h e p r o p o r t i o n t r a n s m i t t e d when t h e r e i s no ca n o p y . S t a n d c h a r a c t e r i s t i c s w i t h h i g h / 2 c l o s e l y a p p r o x i m a t e d t h e t h e o r e t i c a l B e e r ' s law r e l a t i o n s h i p and i n t e g r a t e d f a c t o r s t h a t s e r v e d a s c o r r e l a t e s o f L A I . Where t h e r e was e x t e n s i v e i n t e r - p l o t v a r i a t i o n and t a l l HBLC's (CWHa), MCC a c c o u n t e d f o r more of t h e v a r i a t i o n i n t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n t h a n p l o t o r p r i s m v a r i a b l e s ( T a b l e s 3.3 a n d 3. 4 ) . In t h e CWHb, however, MCC was p o o r e r t h a n p l o t v a r i a b l e s a t p r e d i c t i n g DIFFUSE and PAR. D e t e r m i n i n g MCC i n t h e CWHb was d i f f i c u l t w i t h measurements o f t e n b e i n g made w i t h i n t r e e c rowns r a t h e r t h a n below them, and t h e r e f o r e n o t r e p r e s e n t i n g o v e r s t o r y c o v e r a s i n t h e CWHa. MCC measurements a l s o were made a t t h e h e i g h t o f , o r s l i g h t l y a bove t h e h e i g h t o f r a d i a t i o n s e n s o r s . E x t e n s i v e s c a t t e r o f t h e d i r e c t beam w i t h i n crowns of t r e e s i n t h e CWHb p l o t s was p o o r l y a c c o u n t e d f o r by MCC b e c a u s e s t a n d s t r u c t u r e a f f e c t e d MCC measurements. T h e r e were s l i g h t d i f f e r e n c e s between p l o t and p r i s m v a r i a b l e s . DIFFUSE was b e t t e r r e l a t e d t o t h e p l o t s amples SDI and BA t h a n t o p r i s m samples SDI and BA ( T a b l e s 3.3 and 3. 4 ) . Much o f t h e d i f f u s e r a d i a t i o n was s c a t t e r e d d i r e c t beam w h i c h w o u l d be r e f l e c t e d downward by t r e e c r o w n s . D i f f u s e r a d i a t i o n i n t h e p l o t w o u l d t h e r e f o r e be more r e l a t e d t o o v e r h e a d c a n o p y 65 on sunny d a y s i n summer t h a n t o t r e e s o u t s i d e t h e p l o t . GLOBAL and DIRECT were b e t t e r r e l a t e d t o p l o t t r e e measurements i n t h e CWHa and f o r combined d a t a t h a n t o p r i s m s a m p l e s ( T a b l e s 3.3 and 3 . 4 ) . In t h e CWHb, however, GLOBAL and DIRECT were b e t t e r r e l a t e d t o p r i s m s a m p l e s . B e c a u s e t r e e s i n t h e CWHb s t a n d were of r e l a t i v e l y t h e same s i z e and s p a c i n g , p r i s m s a m p l i n g c h a r a c t e r i z e d t h e s t a n d a c c u r a t e l y . Where t h e r e was e x t e n s i v e i n t e r - p l o t v a r i a t i o n i n t r e e s i z e and s p a c i n g , however, p l o t s a m p l e s were more r e p r e s e n t a t i v e of t h e s t a n d n e a r t h e s e n s o r s . M i l l e r (1959) b e l i e v e d t h a t SUMDIA was s u p e r i o r t o crown c l o s u r e and BA as a measure o f t r a n s m i s s i o n . B e c a u s e l e a f a r e a c a n be p r e d i c t e d f r o m t r e e d i a m e t e r s ( e . g . , G h o l z e t a l . 1976; S p i t t l e h o u s e 1981), SUMDIA would i n t e g r a t e t r e e LAI and t r e e d e n s i t y . J a c k s o n and H a r p e r ( 1 9 5 5 ) , P e r r y e t a l . ( 1 9 6 9 ) , and my r e s u l t s ( T a b l e 3.4) i n d i c a t e d t h a t b a s a l a r e a i s a u s e f u l p r e d i c t o r o f t r a n s m i s s i o n , a l t h o u g h n o t as good a s SUMDIA o r SDI. M i l l e r (1959) a l s o b e l i e v e d t h a t crown c l o s u r e a l o n e was no t an a d e q u a t e p r e d i c t o r o f t r a n s m i s s i o n b e c a u s e a t t e n u a t i o n o f r a d i a t i o n was a l s o a f u n c t i o n o f crown d e p t h . MCC a l o n e d i d n o t p r e d i c t t r a n s m i s s i o n o f d i r e c t and g l o b a l r a d i a t i o n a s w e l l a s o t h e r s t a n d c h a r a c t e r i s t i c s ( T a b l e 3 . 4 ) . Crown d e p t h i s r e l a t e d t o t r e e s i z e and d e n s i t y . S t a n d c h a r a c t e r i s t i c s t h a t i n t e g r a t e t r e e s i z e and d e n s i t y s u c h a s SUMDIA o r SDI a l s o i n t e g r a t e crown d e p t h . 66 S t u d i e s have d e m o n s t r a t e d t h e v e r t i c a l d i s t r i b u t i o n o f r a d i a t i o n w i t h i n c o n i f e r o u s s t a n d s ( e . g . , Norman and J a r v i s 1974; H a r d y 1975; S i n c l a i r and K n o e r r 1982) but t h e i n f l u e n c e o f crown d e p t h among s t a n d s has r e c e i v e d l i t t l e a t t e n t i o n . As a s i n g l e v a r i a b l e crown d e p t h d i d n o t p r e d i c t t r a n s m i s s i o n w e l l , p r o b a b l y b e c a u s e o f t h e c o n f o u n d i n g e f f e c t s of s t a n d d e n s i t y o r MCC. C o e f f i c i e n t s f o r crown d e p t h i n m u l t i p l e r e g r e s s i o n s were no t s i g n i f i c a n t l y d i f f e r e n t f r o m z e r o . Any e s t i m a t e o f o v e r s t o r y c o v e r made u s i n g an i n s t r u m e n t w i t h a m o d e r a t e l y wide a n g l e w i l l i n c l u d e some d e p t h o f crowns (Pyke and Zamora 1982; V a l e s and B u n n e l l 1986; B u n n e l l and V a l e s 1986) and p o s s i b l y s e r v e a s a b e t t e r i n t e g r a t o r o f t h e t h r e e - d i m e n s i o n a l n a t u r e of t h e i n t e r c e p t i n g s u r f a c e . The 10° a r c moosehorn, however, a d e q u a t e l y sampled t h e o v e r s t o r y and was an a c c e p t a b l e v a r i a b l e p r e d i c t i n g t r a n s m i s s i o n . The moosehorn a l s o shows l i t t l e b i a s and i s an a c c u r a t e p r e d i c t o r o f u n d e r s t o r y abundance ( B u n n e l l and V a l e s 1986) w h i c h would be i n f l u e n c e d by r a d i a t i o n ( C h a p t e r 4 ) . — h V C o e f f i c i e n t b i n t h e e e q u a t i o n s showed a c o n s i s t e n t p a t t e r n among o v e r s t o r y v a r i a b l e s f o r r a t e of e x t i n c t i o n o f t h e d i f f e r e n t r a d i a t i o n c o mponents. S l o p e s were s t e e p e s t ( r a t e o f e x t i n c t i o n f a s t e s t ) f o r t r a n s m i s s i o n o f PPFD, f o l l o w e d by d i r e c t , g l o b a l , and t h e n d i f f u s e r a d i a t i o n . C a n o p i e s a b s o r b e d d i f f u s e PPFD ( T a b l e 3 . 2 ) . The d r o p i n d i r e c t r a d i a t i o n t r a n s m i t t e d was g r e a t e r t h a n g l o b a l b e c a u s e g l o b a l a l s o c o n t a i n s d i f f u s e r a d i a t i o n w h i c h was a t t e n u a t e d t h e s l o w e s t . D i r e c t r a d i a t i o n was a l s o c o n v e r t e d t o d i f f u s e 67 r a d i a t i o n w h i c h c a u s e d t h e s t e e p s l o p e f o r a t t e n u a t i o n o f d i r e c t r a d i a t i o n and s h a l l o w s l o p e f o r e n r i c h e d d i f f u s e r a d i a t i o n . Equation differences L i n e a r r e g r e s s i o n e q u a t i o n s p r e d i c t i n g DIRECT f r o m l o g and r e c i p r o c a l l y t r a n s f o r m e d i n d e p e n d e n t v a r i a b l e s d i d not d i f f e r s i g n i f i c a n t l y between s u b z o n e s ( s t a n d s t r u c t u r e s ; p > 0.05). A l l r e g r e s s i o n s p r e d i c t i n g DIFFUSE d i f f e r e d between s u b z o n e s (p < 0 . 0 5 ) . T e s t s of r e g r e s s i o n s p r e d i c t i n g PAR and GLOBAL between s u b z o n e s were e q u i v o c a l , sometimes d i f f e r i n g w i t h i n d e p e n d e n t v a r i a b l e o r form o f r e g r e s s i o n . The t e s t s o f e q u a t i o n s were between b r o a d c l a s s e s o f s t a n d s t r u c t u r e and not t e s t s of subzone e f f e c t s . Si t e fact ors P a i r e d c o m p a r i s o n s of t h e d i f f u s e s i t e f a c t o r ( e s t i m a t e d p h o t o g r a p h i c a l l y ; A n d e r s o n 1964a; V a l e s and B u n n e l l 1986) w i t h m e asured t r a n s m i s s i o n ( T a b l e 3.5) w i t h i n s u b z o n e s and i n c l u d i n g a l l p l o t s f o u n d d i f f e r e n c e s between t h e d i f f u s e s i t e f a c t o r and t h e p r o p o r t i o n s t r a n s m i t t e d o f d i f f u s e r a d i a t i o n and PAR (p < 0.05, n = 11). The d i f f u s e s i t e f a c t o r was l o w e r t h a n t h e measured t r a n s m i s s i o n o f d i f f u s e and h i g h e r t h a n PAR ( T a b l e 3 . 5 ) . No d i f f e r e n c e was f o u n d between t h e d i r e c t s i t e f a c t o r and measured t r a n s m i s s i o n o f d i r e c t r a d i a t i o n o v e r a l l p l o t s (p > 0.05, n = 11), a l t h o u g h t h e d i r e c t s i t e f a c t o r was much h i g h e r on a l l b u t 2 p l o t s . T e s t s e x c l u d i n g p l o t s 7 and TABLE 3.5 C o m p a r i s o n o f d i f f u s e and d i r e c t s i t e f a c t o r s o b t a i n e d f r o m h e m i s p h e r i c a l p h o t o g r a p h s t o measured p r o p o r t i o n s of s o l a r r a d i a t i o n components t r a n s m i t t e d P l o t D i f f u s e 0 s i t e f a c t o r D i f f u s e * D i f f u s e * PAR D i r e c t 0 s i t e f a c t o r D i r e c t * 1 0.092 0.177 0.010 0.139 0.008 2 0.119 0.360 0.050 0.180 0.053 5 0. 1 26 0.260 0.069 0.1 53 0.046 6 0.111 0.286 0.088 0.193 0.058 7 0.318 0.775 0.286 0.258 0.429 21 0.239 1 .429 0.261 0.170 0.127 22 0.248 1 .799 0.216 0. 185 0.416 23 0.112 0.569 0.036 0.089 0.006 24 0.150 1 . 1 53 0.112 0.114 0.035 26 0.072 0.338 0.016 0.151 0.005 27 0. 108 1 .293 0.080 0. 140 0.039 ^ E s t i m a t e d f r o m h e m i s p h e r i c a l p h o t o g r a p h s . M e a s u r e d p r o p o r t i o n o f s o l a r r a d i a t i o n t r a n s m i t t e d . 69 22 f o u n d s i g n i f i c a n t d i f f e r e n c e s (p < 0.05, n = 9 ) . P l o t s 7 and 22 were t h e most open p l o t s and were more s p a t i a l l y h e t e r o g e n e o u s t h a n d e n s e r p l o t s . Lower measured t r a n s m i s s i o n o f d i r e c t r a d i a t i o n may be a r e s u l t o f s e n s o r l o c a t i o n s b e i n g d i f f e r e n t f r o m p h o t o g r a p h p o i n t s and t h e s p a t i a l v a r i a b i l i t y of d i r e c t r a d i a t i o n . The d i r e c t s i t e f a c t o r was f o r 21 M a r c h t o 23 September r a t h e r t h a n j u s t f o r t h e d a y s s a m p l e d f o r r a d i a t i o n . An a n a l y s i s was a l s o done u s i n g t h e d i r e c t s i t e f a c t o r o b t a i n e d f r o m t h e s o l a r p a t h o n l y f o r d a y s when r a d i a t i o n was s a m p l e d . T h i s s i t e f a c t o r was h i g h e r (more open) t h a n f o r t h e e n t i r e summer. H o u r l y c o m p a r i s o n s between t h e d i r e c t s i t e f a c t o r f o r d a y s when r a d i a t i o n was sampled and h o u r l y m e asured p r o p o r t i o n s t r a n s m i t t e d were s i g n i f i c a n t l y d i f f e r e n t (p < 0.05). The d i r e c t s i t e f a c t o r u s e d was f o r e i g h t h o u r s c e n t e r e d on s o l a r noon. C o m p a r i s o n s between t h e d i r e c t s i t e f a c t o r and m e asured p r o p o r t i o n s t r a n s m i t t e d c a l c u l a t e d f o r t h e same 8-hour p e r i o d were a l s o s i g n i f i c a n t l y d i f f e r e n t (p < 0.05). The p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d may have been low b e c a u s e o f s c a t t e r i n g o f t h e d i r e c t beam and c o n v e r t i n g i t t o d i f f u s e r a d i a t i o n . S m a l l gaps i n t h e c a n o p y t h a t were s e e n on t h e p h o t o s were assumed t o t r a n s m i t t h e f u l l i n t e n s i t y o f d i r e c t r a d i a t i o n . But many of t h e s e gaps were s m a l l e r t h a n t h e s u n ' s d i a m e t e r ( 0 . 5 ° ) , c o n s e q u e n t l y d i f f u s i n g t h e d i r e c t beam, and r e d u c i n g t h e p r o p o r t i o n t r a n s m i t t e d . A more a c c u r a t e a s s e s s m e n t o f t h e d i r e c t s i t e f a c t o r may be made i f c o n s i d e r a t i o n i s g i v e n t o t h e r e l a t i o n s h i p among t r e e h e i g h t , 70 sun d i a m e t e r , and d i s t a n c e and a n g l e of a canopy gap ( e . g . , M u l l e r 1971:3) from t h e p h o t o g r a p h l o c a t i o n . A n d e r s o n (1964a) and L i n d r o t h and P e r t t u (1981) f o u n d a greement between e s t i m a t e d and measured cano p y t r a n s m i s s i o n . B u n n e l l and V a l e s (1986) f o u n d t h a t t h e r e l a t i o n s h i p between s a l a l (Gaultheria shall on P u r s h ) u n d e r s t o r y abundance and s i t e f a c t o r s was p o o r e r t h a n r e l a t i o n s h i p s d e v e l o p e d f r o m o t h e r methods u s e d t o e s t i m a t e o v e r s t o r y c o v e r . A d d i t i o n a l d a t a ( C h a p t e r 4 and A p p e n d i x 21) i n d i c a t e d t h a t s a l a l a bundance was more c l o s e l y r e l a t e d t o measured t r a n s m i s s i o n o f s o l a r r a d i a t i o n t h a n t o e i t h e r d i f f u s e o r d i r e c t s i t e f a c t o r s . The u n d e r s t o r y , however, may be r e g u l a t e d by t r a n s m i s s i o n o f r a d i a t i o n d u r i n g a s h o r t t i m e o f t h e y e a r o t h e r t h a n t h e t i m e of y e a r sampled by t h e s i t e f a c t o r s I u s e d . A n d e r s o n ' s (1964a) d i f f u s e s i t e f a c t o r i s an a v e r a g e o v e r a y e a r and i s f o r d i f f u s e s k y r a d i a t i o n a s s u m i n g a s t a n d a r d o v e r c a s t sky b r i g h t n e s s d i s t r i b u t i o n . D i f f e r e n c e s f o u n d h e r e may a r i s e f r o m p l o t s b e i n g s a m p l e d f o r o n l y a s h o r t t i m e p e r i o d , b e c a u s e o f d i f f u s e e n r i c h m e n t by d i r e c t beam s c a t t e r i n g , o r b e c a u s e of s a m p l i n g r a d i a t i o n on sunny d a y s w i t h a d i f f e r e n t s ky b r i g h t n e s s d i s t r i b u t i o n . B e c a u s e much o f th e b e l o w - c a n o p y d i f f u s e r a d i a t i o n o r i g i n a t e d f r o m t h e s c a t t e r o f d i r e c t beam r a d i a t i o n , t h e measured p r o p o r t i o n o f d i f f u s e r a d i a t i o n t r a n s m i t t e d was h i g h e r t h a n t h e d i f f u s e s i t e f a c t o r f o r d i f f u s e s ky r a d i a t i o n . A n d e r s o n (1964a) s t a t e d t h a t p h o t o g r a p h i c e s t i m a t i o n of t h e d i f f u s e s i t e f a c t o r c a n be i n e r r o r f o r one p a r t i c u l a r d ay. Lower d i f f u s e s i t e f a c t o r s may 71 a l s o be a t t r i b u t e d t o p h o t o g r a p h s b e i n g d e l i b e r a t e l y u n d e r e x p o s e d t o o b t a i n c o n t r a s t , b u t t h i s d o e s n o t e x p l a i n t h e o v e r e s t i m a t e o f t h e d i r e c t s i t e f a c t o r . Generality of equations A d i s c u s s i o n on t h e g e n e r a l i t y o f e q u a t i o n s p r e s e n t e d i n t h i s s t u d y r e q u i r e s u n d e r s t a n d i n g o f how p r o p o r t i o n s o f t h e d i f f e r e n t r a d i a t i o n components t r a n s m i t t e d a r e a f f e c t e d by c l o u d i n e s s and s o l a r a l t i t u d e w i t h i n and among s t a n d s . D i f f u s e and d i r e c t r a d i a t i o n a r e t r a n s m i t t e d d i f f e r e n t l y , a r e e a c h a f f e c t e d by s t a n d s t r u c t u r e , and i n t e r a c t t o a f f e c t t h e p r o p o r t i o n o f g l o b a l r a d i a t i o n t r a n s m i t t e d . I w i l l b r i e f l y d i s c u s s how t r a n s m i s s i o n o f d i f f u s e , d i r e c t , and g l o b a l r a d i a t i o n a r e a f f e c t e d by c l o u d s and s o l a r a l t i t u d e w i t h i n a s t a n d , and a p p l y t h e d i s c u s s i o n t o d i f f e r e n c e s i n s t a n d s t r u c t u r e among s t a n d s . A n d e r s o n (1970) c o n c l u d e d and R e i f s n y d e r e t a l . (1971/72) assumed t h a t t h e f r a c t i o n o f d i f f u s e sky r a d i a t i o n t r a n s m i t t e d by a f o r e s t i s n o t much a f f e c t e d by w e a t h e r . R e l a t i o n s h i p s d e v e l o p e d h e r e a r e b a s e d on t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n t h a t i n c l u d e d b e l o w - c a n o p y d i r e c t beam s c a t t e r i n g . W i t h i n c r e a s i n g c l o u d i n e s s , t h e amount o f d i r e c t r a d i a t i o n i n a b o v e - c a n o p y g l o b a l r a d i a t i o n i s r e d u c e d and t h e r e i s l e s s d i r e c t r a d i a t i o n a v a i l a b l e f o r s c a t t e r i n g i n c a n o p i e s . P r o p o r t i o n s o f d i f f u s e r a d i a t i o n t r a n s m i t t e d t h a t i n c l u d e d i r e c t - b e a m s c a t t e r i n g s h o u l d d e c r e a s e w i t h i n c r e a s i n g c l o u d i n e s s . The p r o p o r t i o n s of d i f f u s e r a d i a t i o n t r a n s m i t t e d 72 by c a n o p i e s d e c r e a s e d w i t h i n c r e a s e d c l o u d c o v e r on 8 of 8 p l o t s t h a t were sampl e d o v e r 2 f u l l c o n s e c u t i v e d a y s w i t h 2 d i f f e r e n t c l o u d c o n d i t i o n s . P r o p o r t i o n s t r a n s m i t t e d by t h e CWHb p l o t s were l e s s t h a n 1.0 w i t h i n c r e a s i n g c l o u d s . H u t c h i s o n and M a t t (1977) f o u n d a d e c r e a s e i n t h e p r o p o r t i o n o f d i f f u s e r a d i a t i o n t r a n s m i t t e d on o v e r c a s t d a y s compared t o c l e a r d a y s i n a hardwood s t a n d , d e m o n s t r a t i n g t h e i n f l u e n c e o f s c a t t e r e d d i r e c t beam r a d i a t i o n ( H u t c h i s o n and M a t t 1976). M u l l e r (1971) r e p o r t e d t h a t downward s c a t t e r o f d i r e c t r a d i a t i o n was a b o u t o n e - h a l f o f t h e t o t a l d i f f u s e r a d i a t i o n below Pinus s p p . c a n o p i e s , and t h a t s c a t t e r i n g was g r e a t e s t i n open s t a n d s . He c o n c l u d e d t h a t u nder c l e a r - s k y c o n d i t i o n s , t h e p r i m a r y s o u r c e o f d i f f u s e r a d i a t i o n below c a n o p i e s was fr o m s c a t t e r i n g o f d i r e c t r a d i a t i o n by t r e e c r o w n s . S c a t t e r e d d i r e c t was a b o u t o n e - t h i r d o f t h e t o t a l d i f f u s e r a d i a t i o n below a Pinus resinosa A i t . c a n o p y i n R e i f s n y d e r e t a l . ' s (1971/72) s t u d y . I f t h e e s t i m a t e d d i f f u s e s i t e f a c t o r a c c u r a t e l y r e f l e c t s t h e p r o p o r t i o n o f d i f f u s e s k y r a d i a t i o n t r a n s m i t t e d , t h e n s c a t t e r i n g o f d i r e c t beam a c c o u n t e d f o r 50 t o 92% of t h e d i f f u s e r a d i a t i o n below c a n o p i e s i n t h i s s t u d y . B e c a u s e much o f t h e d i f f u s e sky r a d i a t i o n p e n e t r a t i o n comes f r o m 10° o f t h e s o l a r d i s k on c l e a r d a y s , t r a n s m i s s i o n o f d i f f u s e i s d e p e n d e n t on canopy o p e n i n g s n e a r t h e p a t h of t h e sun ( H u t c h i s o n e t a l . 1980). C h a n g i n g s o l a r a l t i t u d e w i l l a f f e c t d i r e c t beam s c a t t e r i n g ( H u t c h i s o n and M a t t 1976) and ca n o p y o p e n i n g s i n t h e s o l a r p a t h g e n e r a l l y i n c r e a s e w i t h a n g l e above t h e h o r i z o n ( H u t c h i s o n e t a l . 1980; L i n d r o t h and 73 P e r t t u 1981). T h e r e i s l e s s s c a t t e r i n g of d i r e c t beam i n t r e e c a n o p i e s a s c l o u d i n e s s i n c r e a s e s , and t h e e q u a t i o n s p r e s e n t e d w i l l n o t a c c u r a t e l y p r e d i c t t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n on c l o u d y d a y s and a t o t h e r t i m e s of t h e y e a r . L i t t l e i n f o r m a t i o n i s a v a i l a b l e . o n t h e e f f e c t s o f c l o u d s on t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d . I f o u n d t h a t t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d i n c r e a s e d w i t h i n c r e a s i n g c l o u d i n e s s on f i v e o f e i g h t p l o t s . The i n c r e a s e d t r a n s m i s s i o n was u n e x p e c t e d and may be due t o e r r o r s i n t h e way d i r e c t r a d i a t i o n was c a l c u l a t e d ( g l o b a l - d i f f u s e ) and l a c k o f c o r r e c t i o n f a c t o r f o r t h e sh a d e d s e n s o r . The t h r e e p l o t s i n w h i c h t r a n s m i s s i o n o f d i r e c t d e c r e a s e d were t h e most open and had t h e h i g h e s t d i r e c t s i t e f a c t o r s . F o r c l e a r d a y s , d e c r e a s i n g s o l a r a l t i t u d e w o u l d d e c r e a s e t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d ( A n d e r s o n 1970) p r o v i d e d gap f r e q u e n c y d e c r e a s e d f r o m z e n i t h t o h o r i z o n . I f r e l a t i v e gap f r e q u e n c y i n t h e s o l a r p a t h among a l l p l o t s s a m p l e d was s i m i l a r a t a l l s o l a r a n g l e s , t h e n a change i n s o l a r a l t i t u d e may a f f e c t a l l p l o t s s i m i l a r i l y u nder c l e a r s k i e s . The s l o p e o f t h e p r e d i c t i v e e q u a t i o n s w o u l d r e m a i n t h e same, b u t t h e i n t e r c e p t w o u l d c h a n g e ; A d d i n g a t e r m t o a c c o u n t f o r s o l a r a l t i t u d e (/3) t o t h e r e g r e s s i o n e q u a t i o n s ( e . g . , a e i X ^ c s c ' 3 1 ^ J a r v i s e t a l . 1976) may improve t h e a c c u r a c y o f p r e d i c t i o n s under c l e a r s k y c o n d i t i o n s a t a n o t h e r t i m e o f t h e y e a r . The e f f e c t s o f i n c r e a s i n g c l o u d s , however, would c o m p l i c a t e t h e r e l a t i o n s h i p o f t r a n s m i s s i o n o f d i r e c t r a d i a t i o n t o s t a n d c h a r a c t e r i s t i c s o v e r a ra n g e o f s o l a r a l t i t u d e s . 74 M i l l e r (1959) c i t e d s e v e r a l s t u d i e s where t h e p r o p o r t i o n of g l o b a l r a d i a t i o n t r a n s m i t t e d i n c r e a s e d w i t h i n c r e a s i n g c l o u d i n e s s . Z a v i t k o v s k i (1974) and H u t c h i s o n and M a t t (1977) f o u n d o p p o s i t e r e s u l t s . I f o u n d t h a t i n 5 of 8 p l o t s t h e p r o p o r t i o n o f g l o b a l r a d i a t i o n t r a n s m i t t e d i n c r e a s e d w i t h i n c r e a s i n g c l o u d c o v e r , t h o u g h i r r a d i a n c e was l o w e r t h a n on sunny d a y s . S t a n d s t r u c t u r e w o u l d a f f e c t t h e p r o p o r t i o n o f g l o b a l t r a n s m i t t e d . I f t h e r e a r e gaps i n t h e p a t h o f t h e sun t r a n s m i t t i n g a p p r e c i a b l e d i r e c t r a d i a t i o n on sunny d a y s , and on c l o u d y d a y s l i g h t i s t r a n s m i t t e d t h r o u g h gaps a t a l l a n g l e s , t h e n t h e p r o p o r t i o n o f g l o b a l r a d i a t i o n t r a n s m i t t e d may d e c r e a s e on c l o u d y d a y s i n a p l o t w i t h a d e n s e o v e r h e a d c a n o p y . On t h e o t h e r hand, i f a p l o t t r a n s m i t s l i t t l e d i r e c t r a d i a t i o n , but has gaps i n a r e a s o f t h e c a n o p y o t h e r t h a n i n t h e s o l a r p a t h , t h e n t h e p r o p o r t i o n o f g l o b a l r a d i a t i o n t r a n s m i t t e d may i n c r e a s e on c l o u d y d a y s . T h o s e p l o t s showing a d e c r e a s e i n t r a n s m i s s i o n of g l o b a l r a d i a t i o n w i t h i n c r e a s i n g c l o u d i n e s s had t h e h i g h e s t r a t i o s o f p r o p o r t i o n d i r e c t t r a n s m i t t e d t o p r o p o r t i o n d i f f u s e t r a n s m i t t e d . . I n t h e most open p l o t s e x t e n s i v e s c a t t e r i n g o f d i r e c t r a d i a t i o n on c l e a r d a y s would be r e d u c e d on c l o u d y d a y s and t h e p r o p o r t i o n o f g l o b a l t r a n s m i t t e d may d e c r e a s e . D u r i n g w i n t e r w i t h low s o l a r e l e v a t i o n , p e n e t r a t i o n of d i r e c t r a d i a t i o n and downward s c a t t e r i n g o f d i r e c t beam a r e m i n i m a l b e c a u s e o f t h e a c u t e a n g l e o f t h e sun t o t r e e crowns and i n c r e a s e d a l b e d o . On c l o u d y d a y s t h e n , t h e p r o p o r t i o n o f g l o b a l t r a n s m i t t e d may i n c r e a s e b e c a u s e d i f f u s e r a d i a t i o n i s e n t e r i n g t h r o u g h many 75 c anopy g a p s . But f o r t h e same canopy t r a n s m i t t i n g a p p r e c i a b l e d i r e c t r a d i a t i o n d u r i n g summer, t h e p r o p o r t i o n o f g l o b a l t r a n s m i t t e d may d e c r e a s e w i t h i n c r e a s i n g c l o u d s . L i n d r o t h and P e r t t u (1981) showed t h a t t r a n s m i s s i o n o f g l o b a l r a d i a t i o n d e c r e a s e d w i t h d e c r e a s i n g s o l a r a l t i t u d e i n a Pinus syl vest ri s L. s t a n d . S l a u g h t e r ( 1 9 8 3 ) , t h o u g h , f o u n d no c o n s i s t e n t change i n t r a n s m i s s i o n w i t h c h a n g e s i n c l o u d c o v e r o r s o l a r a l t i t u d e i n a Picea mariana ( M i l l . ) B.S.P. s t a n d s a m p l e d d u r i n g May-September. In summary, t h e e q u a t i o n s p r e d i c t i n g t h e p r o p o r t i o n o f d i f f u s e r a d i a t i o n t r a n s m i t t e d t h a t i n c l u d e d i r e c t beam s c a t t e r i n g would change w i t h i n c r e a s i n g c l o u d i n e s s and a t d i f f e r e n t t i m e s of t h e y e a r . E q u a t i o n s p r e d i c t i n g t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d would l i k e l y be a f f e c t e d by weather c o n d i t i o n s and a r e h i g h l y d e p e n d e n t upon s o l a r a l t i t u d e . A d d i n g a t e r m t o a c c o u n t f o r s o l a r a n g l e may br o a d e n t h e g e n e r a l i t y o f t h e e q u a t i o n s , i f r e l a t i v e gap f r e q u e n c y i n t h e s o l a r p a t h among s t a n d s i s assumed t h e same. E q u a t i o n s p r e d i c t i n g t r a n s m i s s i o n of g l o b a l r a d i a t i o n a r e a f f e c t e d by t h e p r o p o r t i o n s o f d i f f u s e and d i r e c t r a d i a t i o n t r a n s m i t t e d , c l o u d c o v e r , and i n t e r a c t i o n w i t h s t a n d s t r u c t u r e . CONCLUSION A l t h o u g h e q u a t i o n s p r e d i c t i n g t r a n s m i s s i o n o f r a d i a t i o n components may n o t g i v e a c c u r a t e e s t i m a t e s when u s e d under d i f f e r e n t sky c o n d i t i o n s , o r s o l a r a l t i t u d e s , t h e y do d e m o n s t r a t e t h e r e l a t i o n s h i p s between t r a n s m i s s i o n and s t a n d c h a r a c t e r i s t i c s f o r a g i v e n t i m e p e r i o d u nder s p e c i f i c sky c o n d i t i o n s . The r e s u l t s o f o t h e r s t u d i e s s u g g e s t i n g t h e use o f sum of d i a m e t e r s t o p r e d i c t t r a n s m i s s i o n o f s o l a r r a d i a t i o n a r e c o n f i r m e d . R e i n e k e ' s (1933) s t a n d d e n s i t y i n d e x has m e r i t a s a p r e d i c t o r v a r i a b l e , and i s an e a s i l y m e a s u r e d i n d e x t h a t has not been u s e d p r e v i o u s l y t o p r e d i c t t r a n s m i s s i o n . O v e r s t o r y c o v e r i s an a p p a r e n t l y good i n t e g r a t o r o f i n t e r - p l o t v a r i a t i o n o nce HBLC's a r e above s e n s o r s , and i s u s e f u l f o r p r e d i c t i n g t r a n s m i s s i o n o f d i f f u s e and d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n . E x t i n c t i o n of d i f f u s e r a d i a t i o n i s b e s t p r e d i c t e d u s i n g o v e r s t o r y c o v e r as m e asured by a 10° a n g l e moosehorn. E x t i n c t i o n o f g l o b a l and d i r e c t r a d i a t i o n f o l l o w i n g B e e r ' s law i s b e s t p r e d i c t e d u s i n g sum o f t r e e d i a m e t e r s o r s t a n d d e n s i t y i n d e x . E q u a t i o n s p r e d i c t i n g t r a n s m i s s i o n o f d i r e c t r a d i a t i o n d i d n o t d i f f e r between t h e two b r o a d c l a s s e s of s t a n d s t r u c t u r e . S t a n d s t r u c t u r e a f f e c t e d t r a n s m i s s i o n of d i f f u s e r a d i a t i o n r e s u l t i n g i n e q u a t i o n d i f f e r e n c e s . E q u a t i o n d i f f e r n c e s were e q u i v o c a l f o r t r a n s m i s s i o n o f g l o b a l and d i f f u s e p h o t o s y n t h e t i c p h o t o n f l u x d e n s i t y , i n p a r t , b e c a u s e t h e s e two components were a f f e c t e d by t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n . H e m i s p h e r i c a l p h o t o g r a p h i c e s t i m a t e s of t r a n s m i s s i o n o f d i f f u s e , d i f f u s e p h o t o s y n t h e t i c p h o t o n f l u x d e n s i t y , and d i r e c t r a d i a t i o n were s i g n i f i c a n t l y d i f f e r e n t f r o m m e a s u r e d p r o p o r t i o n s t r a n s m i t t e d . REFERENCES A n d e r s o n , M.C. 1964a. S t u d i e s of t h e w o o d l a n d l i g h t c l i m a t e . I . The p h o t o g r a p h i c c o m p u t a t i o n o f l i g h t c o n d i t i o n s . J . E c o l . 52:27-41. A n d e r s o n , M.C. 1964b. L i g h t r e l a t i o n s of t e r r e s t r i a l p l a n t c o m m u n i t i e s and t h e i r measurement. B i o l . Rev. 39:425-486. A n d e r s o n , M.C. 1966. S t a n d s t r u c t u r e and l i g h t p e n e t r a t i o n . I I . A t h e o r e t i c a l a n a l y s i s . J . A p p l . E c o l . 3:41-54. A n d e r s o n , M.C. 1970. I n t e r p r e t i n g t h e f r a c t i o n o f s o l a r r a d i a t i o n a v a i l a b l e i n f o r e s t . A g r i c . M e t e o r o l . 7:19-28. A n d e r s o n , R . C , O.L. L o u c k s , and A.M. Swain. 1969. H e r b a c e o u s r e s p o n s e t o canopy c o v e r , l i g h t i n t e n s i t y , and t h r o u g h f a l l p r e c i p i t a t i o n i n c o n i f e r o u s f o r e s t s . E c o l o g y . 50:255-263. B a l d o c c h i , D., B. H u t c h i s o n , D. M a t t , and R. M c M i l l e n . 1984a. S e a s o n a l v a r i a t i o n s i n t h e r a d i a t i o n r e g i m e w i t h i n an o a k - h i c k o r y f o r e s t . A g r i c . and F o r . M e t e o r o l . 33:177-191. B a l d o c c h i , D., D. M a t t , B. H u t c h i s o n , and R. M c M i l l e n . 1984b. 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Respon s e o f L i n t r o n i c Dome S o l a r i m e t e r s t o v a r y i n g s o l a r r a d i a t i o n f l u x d e n s i t i e s . U.S.-I.B.P. E a s t . F o r . Dec. F o r . Biome Memo R e p t . No. 74-1. M i l l e r , D.H. 1959. T r a n s m i s s i o n o f i n s o l a t i o n t h r o u g h p i n e f o r e s t c a n o p y , a s i t a f f e c t s t h e m e l t i n g o f snow. M i t t . S c h w e i z . A n s t . f o r s t l . V e r s u c h s w e s e n . 35:57-79. M i l l e r , P.C. 1967. L e a f t e m p e r a t u r e s , l e a f o r i e n t a t i o n and e n e r g y exchange i n q u a k i n g a s p e n (Populous tremuloides) and g a m b e l l ' s oak (Quercus gambellii) i n c e n t r a l C o l o r a d o . O e c o l . P l a n t . 2:241-270. M i l l e r , P.C. 1969. S o l a r r a d i a t i o n p r o f i l e s i n o p e n i n g s i n c a n o p i e s o f as p e n and oak. S c i e n c e . 164:308-309. 81 M o n s i , M. and T. S a e k i . 1953. 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P h o t o s y n t h e s i s i n S i t k a s p r u c e (Picea si t chensi s (Bong.) C a r r . ) I I I . Measurements o f c a n o p y s t r u c t u r e and i n t e r c e p t i o n of r a d i a t i o n . J . A p p l . E c o l . 11:375-398. Norman, J.M. and P.G. J a r v i s . 1975. P h o t o s y n t h e s i s i n S i t k a s p r u c e (Picea sitchensis (Bong.) C a r r . ) V. R a d i a t i o n p e n e t r a t i o n t h e o r y and a t e s t c a s e . J . A p p l . E c o l . 12:839-878. P e r r y , T.O., H.E. S e l l e r s , and C O . B l a n c h a r d . 1969. E s t i m a t i o n o f p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n under a f o r e s t c a n o p y w i t h c h l o r o p h y l l e x t r a c t s and fr o m b a s a l a r e a measurements. E c o l o g y . 50:39-44. Pyke, D.A. and B.A. Zamora. 1982. R e l a t i o n s h i p s betwen o v e r s t o r y and u n d e r s t o r y p r o d u c t i o n i n t h e g r a n d f i r / m y r t l e boxwood h a b i t a t t y p e o f n o r t h c e n t r a l I d a h o . J . Range Manage. 35:769-773. R e i f s n y d e r , W.E., G.M. F u r n i v a l , a nd J . L . H o r o w i t z . 1971/72. S p a t i a l and t e m p o r a l d i s t r i b u t i o n o f s o l a r r a d i a t i o n b e n e a t h f o r e s t c a n o p i e s . A g r i c . M e t e o r o l . 9:21-37. R e i n e k e , L.H. 1933. P e r f e c t i n g a s t a n d d e n s i t y i n d e x f o r e v e n - a g e d f o r e s t s . J . A g r i c . R e s . 46:627-638. R o b i n s o n , M.W. 1947. An i n s t r u m e n t t o measure f o r e s t crown c o v e r . F o r . C h r o n . 23:222-225. R o s s , J . 1975. R a d i a t i v e t r a n s f e r i n p l a n t c o m m u n i t i e s , pp. 13-55 in: J . L . M o n t e i t h ( e d . ) . V e g e t a t i o n and t h e A t m o s p h e r e . V o l . 1. P r i n c i p l e s . Academic P r e s s . New Y o r k , NY. R o s s , J . 1981. The r a d i a t i o n r e g i m e and a r c h i t e c t u r e of p l a n t s t a n d s . D r . W. Junk, P u b l . The Hague. S i n c l a i r , T.R. and K.R. K n o e r r . 1982. D i s t r i b u t i o n o f p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n i n t h e canopy of a l o b l o l l y p i n e p l a n t a t i o n . J . A p p l . E c o l . 19:183-191. S l a u g h t e r , C.W. 1983. Summer s h o r t w a v e s o l a r r a d i a t i o n a t a s u b a r c t i c f o r e s t s i t e . Can. J . F o r . Res. 13:740-746. S p i t t l e h o u s e , D.L. 1981. M e a s u r i n g and m o d e l l i n g e v a p o t r a n s p i r a t i o n f r o m D o u g l a s - f i r s t a n d s . Ph.D. t h e s i s . 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 , B.C. S z e i c z , G. 1974. S o l a r r a d i a t i o n f o r p l a n t g r o w t h . J . A p p l . E c o l . 11:617-636. V a l e s , D.J.. and F . L . B u n n e l l . 1986. C o m p a r i s o n o f methods f o r e s t i m a t i n g f o r e s t o v e r s t o r y c o v e r I . O b s e r v e r e f f e c t s and p r e c i s i o n . Can. J . F o r . Res. ( s u b m i t t e d ) . V e z i n a , P.E. and GY P e c h . 1964. S o l a r r a d i a t i o n b e n e a t h c o n i f e r c a n o p i e s i n r e l a t i o n t o crown c l o s u r e . F o r . S c i . 10:443-451. W e l l n e r , C A . 1948. L i g h t i n t e n s i t y r e l a t e d t o s t a n d d e n s i t y i n m ature s t a n d s of t h e w e s t e r n w h i t e p i n e t y p e . J . F o r . 46:16-19. Z a v i t k o v s k i , J . 1974. S o l a r r a d i a t i o n measurements i n t h e E n t e r p r i s e R a d i a t i o n F o r e s t , pp. 33-45 in: T.D. R u d o l p h ( e d ) . The E n t e r p r i s e , W i s c o n s i n , R a d i a t i o n F o r e s t . U.S. A.E.C. TID-26113. Z a v i t k o v s k i , J . 1976. G r o u n d v e g e t a t i o n , b i o m a s s , p r o d u c t i o n , and e f f i c i e n c y o f e n e r g y u t i l i z a t i o n i n some n o r t h e r n W i s c o n s i n f o r e s t e c o s y s t e m s . E c o l o g y . 57:694-706. CHAPTER 4. RELATIONSHIPS OF SALAL (GAULTHERIA SHALLON) TO TRANSMISSION OF SOLAR RADIATION THROUGH FOREST CANOPIES INTRODUCTION S a l a l {Gaultheria shall on P u r s h ) i s a f o r e s t u n d e r s t o r y s p e c i e s w i d e l y d i s t r i b u t e d a l o n g t h e P a c i f i c C o a s t o f N o r t h A m e r i c a . D e s p i t e i t s u b i q u i t o u s d i s t r i b u t i o n i n c o a s t a l f o r e s t s , l i t t l e work has been done on s a l a l e c o l o g y . S a b h a s r (1961) f o u n d t h a t p h o t o s y n t h e s i s o f s a l a l p l a n t s under a f o r e s t c a n o p y was 16% of t h o s e p l a n t s i n t h e open and c o n c l u d e d t h a t s a l a l was an i n t o l e r a n t s p e c i e s . Swank (1972) c o n c l u d e d t h a t s a l a l sun p l a n t s were under g r e a t e r m o i s t u r e s t r e s s t h a n shade p l a n t s . S t a n e k e t a l . (1979) r e p o r t e d t h a t s a l a l c o v e r was p o s i t i v e l y r e l a t e d t o d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n below c o n i f e r o u s f o r e s t c a n o p i e s . F o r e s t e r s a r e c o n c e r n e d w i t h s a l a l b e c a u s e i t c ompetes w i t h t r e e s f o r s o i l m o i s t u r e (Tan e t a l . 1977; B l a c k e t a l . 1980) and p o s s i b l y n u t r i e n t s (Weetman e t a l . 1986). S a l a l has two d i s t i n c t l y d i f f e r e n t g r o w t h f o r m s . S h o o t s i n open a r e a s a r e numerous and s h o r t ( C h a p t e r 2 ) , w i t h t h i c k (Swank 1972), s m a l l l e a v e s ( K e l l i h e r 1985). S h o o t s under c a n o p i e s and i n shade a r e t a l l e r , w i t h l a r g e r , d a r k e r g r e e n l e a v e s . B e c a u s e s a l a l r e s p o n d s t o s m a l l o p e n i n g s i n a f o r e s t c a n o p y w i t h i n c r e a s e d v i g o r ( V a l e s and B u n n e l l 1986) and i s r e l a t e d t o l e v e l s o f f o r e s t s t o c k i n g (Long and T u r n e r 1975; C h a p t e r 2 ) , l i g h t seems t o be an i m p o r t a n t f a c t o r i n s a l a l g r o w t h . S t u d i e s o f f o r e s t u n d e r s t o r y g r o w t h have shown a p o s i t i v e r e l a t i o n s h i p w i t h l i g h t t r a n s m i s s i o n ( e . g . , Z a v i t k o v s k i 1976). A n d e r s o n e t a l . (1969) a l s o f o u n d t h a t u n d e r s t o r y abundance was p o s i t i v e l y c o r r e l a t e d w i t h l i g h t t r a n s m i s s i o n but t h a t t h e u n d e r s t o r y was more r e s p o n s i v e t o t h r o u g h f a l l p r e c i p i t a t i o n t h a n t o l i g h t t r a n s m i s s i o n . I n t e r a c t i o n s between l i g h t and m o i s t u r e a r e p r o b a b l y i m p o r t a n t ( A t z e t and W a r i n g 1970). D i r e c t r a d i a t i o n u n d e r f o r e s t c a n o p i e s i n t h e f o r m o f s u n f l e e k s may r e s u l t i n i n c r e a s e d p h o t o s y n t h e s i s ( e . g . , S h i r l e y 1945; G r o s s and Chabot 1979; G r o s s 1982), i n f l u e n c e p h o t o s y n t h e s i s (Hodges 1967), i n f l u e n c e m o i s t u r e s t a t u s and d i s t r i b u t i o n o f p l a n t s (Young and S m i t h 1979; U s t i n e t a l . 1984), o r have l i t t l e e f f e c t on p l a n t s (Logan 1959). S u n f l e c k s c o n t r i b u t e s i g n i f i c a n t l y t o t h e r a d i a t i o n r e g i m e below a f o r e s t c a n o p y ( E v a n s 1956; C z a r n o w s k i and Slomka 1959; M i l l e r 1959; M u l l e r 1971) and a r e a d d i t i v e t o d i f f u s e r a d i a t i o n ( F e d e r e r and T a n n e r 1966). T h i s s t u d y e xamined t h e r e l a t i o n s h i p o f s a l a l a b undance and s h o o t s i z e t o t r a n s m i s s i o n o f components of s o l a r r a d i a t i o n t h r o u g h f o r e s t c a n o p i e s . S p e c i f i c o b j e c t i v e s were t o : 1) e x p l o r e t h e form o f t h e r e l a t i o n s h i p o f s a l a l d e n s i t y , b a s a l a r e a , p r o d u c t i v i t y , b i o m a s s , c o v e r , and s h o o t s i z e t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e (measured as p h o t o n f l u x d e n s i t y , PPFD) s o l a r r a d i a t i o n ; 2) e v a l u a t e i f t h e r e l a t i o n s h i p s d i f f e r e d between s t a n d s t r u c t u r e s and b i o g e o c l i m a t i c s u b z o n e s ; and 3) e v a l u a t e w h i c h s o l a r r a d i a t i o n component may be t h e most i m p o r t a n t f o r r e g u l a t i n g s a l a l g r o w t h . 86 STUDY AREAS T w e l v e p l o t s were sampled a t s e v e r a l l o c a t i o n s on V a n c o u v e r I s l a n d , B r i t i s h C o l u m b i a , Canada. S i x p l o t s were i n th e C o a s t a l W e s t e r n Hemlock d r y sub z o n e (CWHa; K r a j i n a 1965) and 6 were i n t h e CWH wet subzone (CWHb). P l o t s i n t h e CWHa were i n t h e Gaultheria - w e s t e r n hemlock - D o u g l a s - f i r p l a n t a s s o c i a t i o n ( O r l o c i 1965) and CWHb p l o t s were i n t h e Vaccinium - Gaul t heri a - w e s t e r n hemlock - D o u g l a s - f i r p l a n t a s s o c i a t i o n ( O r l o c i 1965). The CWHa p l o t s were s e p a r a t e d g e o g r a p h i c a l l y and i n s t a n d s of d i f f e r e n t a g e s and s t r u c t u r e s . CWHb p l o t s were a l l l o c a t e d i n t h e same s t a n d a n d s e p a r a t e d by l e s s t h a n 800 m. The CWHb s t a n d was y o u n g e r , w i t h s m a l l e r t r e e s t h a n most s t a n d s sampled i n t h e CWHa. S o i l s were H u m o - F e r r i c P o d z o l s on m o r a i n a l o r c o l l u v i a l v e n e e r . 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 s 2123 mm i n t h e CWHa and abo u t 2350 mm i n t h e CWHb ( K l i n k a e t a l . 1984). A l l p l o t s were i n immature s t a n d s o f D o u g l a s - f i r (Pseudotsuga menziesii ( M i r b . ) F r a n c o ) , w e s t e r n hemlock (Tsuga heterophylla ( R a f . ) S a r g . ) , and w e s t e r n r e d c e d a r (Thuja pii cat a D o n n ) . A d d i t i o n a l t r e e s p e c i e s f o u n d i n t h e CWHb s t a n d were a m a b i l i s f i r (Abies amabilis ( D o u g l . ) F o r b e s ) , y e l l o w - c e d a r (Chamaecyparis nookatensis (D. Don) S p a c h ) , and w e s t e r n w h i t e p i n e (Pinus monticola D o u g l . ) . U n d e r s t o r y s p e c i e s were p r i m a r i l y s a l a l , r e d h u c k l e b e r r y (Vaccinium parvi folium S m i t h ) , and Oregon g r a p e (Mahoni a nervosa P u r s h ) . 87 P l o t s were s e l e c t e d t o encompass a r a n g e o f o v e r s t o r y c o v e r and s a l a l a b u n d a n c e s . C r i t e r i a u s e d t o l o c a t e p l o t s were: homogeneous f o r e s t c a n o p y s t r u c t u r e , no d e c i d u o u s t r e e s , s t a n d age 30-60 y e a r s , no s t a n d t r e a t m e n t ( e . g . , no t h i n n i n g o r f e r t i l i z a t i o n ) , s l o p e s 10-60%, s o u t h - s o u t h w e s t a s p e c t s , and e l e v a t i o n 200-600 m. D e s c r i p t i o n s o f p l o t s a r e g i v e n i n T a b l e 4.1. TABLE 4.1 D e s c r i p t i o n s o f p l o t s u s e d t o sample s a l a l a nd s o l a r r a d i a t i o n P l o t Subzone A s p e c t (°) E l e v . (m) S l o p e (%) Age C o v e r 0 BA (m 2/ha) 1 CWHa 230 430 30 28 0.912 37.7 2 CWHa 215 270 15 37 0.782 46.7 5 CWHa 206 310 52 60 0.636 35.0 6 CWHa 215 310 45 59 0.783 34.4 7 CWHa 1 73 200 9 34 0.345 14.8 9 CWHa 261 630 43 42 0.899 54.9 21 CWHb 240 570 30 30 0.576 10.1 22 CWHb 240 570 30 30 0.416 8.5 23 CWHb 220 570 20 30 0.809 41 .6 24 CWHb 220 570 20 30 0.636 26. 1 26 CWHb 219 550 19 30 0.902 38.9 27 CWHb 214 600 22 30 0.757 17.5 flForest o v e r s t o r y c o v e r e s t i m a t e d by moosehorn ( R o b i n s o n 1947) a s a p r o p o r t i o n o f 1.0. 89 METHODS D e t a i l e d methods f o r s a m p l i n g s a l a l and s o l a r r a d i a t i o n a r e g i v e n i n C h a p t e r s 2 and 3. B r i e f l y , s a l a l was sampled i n 52 0.25-m 2 q u a d r a t s s y s t e m a t i c a l l y l o c a t e d w i t h i n 9 x 25 m (0.0225 ha) p l o t s w i t h t h e l o n g edge l a i d o u t a l o n g s l o p e c o n t o u r s . S a l a l c o v e r was v i s u a l l y e s t i m a t e d i n e a c h q u a d r a t . A l l s a l a l s h o o t s r o o t e d i n t h e q u a d r a t were c o u n t e d , measured f o r b a s a l d i a m e t e r and h e i g h t ( d i s t a n c e from g r o u n d where r o o t e d t o t o p o f p r e v i o u s y e a r ' s g r o w t h when t h e s h o o t was p u l l e d u p r i g h t ) , and c u r r e n t g r o w i n g s e a s o n ' s l e a v e s were c o u n t e d . T o t a l b i o m a s s o f ea c h s h o o t was e s t i m a t e d from a l l o m e t r i c e q u a t i o n s ( V a l e s e t a l . i n p r e p . ) and d i d n o t i n c l u d e c u r r e n t a n n u a l g r o w t h (CAG) b i o m a s s . CAG f o l i a r b i o m a s s was e s t i m a t e d by m u l t i p l y i n g t h e number o f CAG l e a v e s by a v e r a g e l e a f b i o m a s s o b t a i n e d from a random sample of l e a v e s a f t e r t h e g r o w i n g s e a s o n . Q u a d r a t s a m p l e s and s h o o t measurements were t r a n s f o r m e d t o o b t a i n n o r m a l d i s t r i b u t i o n s . Means and c o n f i d e n c e i n t e r v a l s of t r a n s f o r m e d s a m p l e s and s h o o t measurements a r e r e p o r t e d b a c k t r a n s f o r m e d . E s t i m a t e s o f d e n s i t y , b a s a l a r e a , and b i o m a s s a r e g i v e n as p l o t a v e r a g e s (n = 5 2 / p l o t ) and r e p o r t e d p e r m 2. E s t i m a t e s of s h o o t h e i g h t and b a s a l d i a m e t e r a r e p l o t a v e r a g e s of measurements o f a l l s h o o t s s a m p l e d i n a p l o t . S h o r t w a v e s o l a r r a d i a t i o n (0.3-3.0 um) was m o n i t o r e d w i t h Dome s o l a r i m e t e r s ( L i n t r o n i c L t d . ) r e c o r d e d on CR-21 d a t a l o g g e r s a s 3-minute a v e r a g e s of samp l e s t a k e n a t 1-minute 90 i n t e r v a l s . Shadow bands ( H o r o w i t z 1969) s e p a r a t e d d i f f u s e f r o m g l o b a l r a d i a t i o n w i t h p a i r e d s e n s o r s on e a c h s t a n d mounted 1.5 m above g r o u n d . One p a i r o f s e n s o r s r e c o r d e d s o l a r r a d i a t i o n i n an open a r e a n e a r t h e p l o t t o d e t e r m i n e t h e amount of r a d i a t i o n p o t e n t i a l l y above t h e c a n o p y . Two p a i r s of s e n s o r s were l o c a t e d 11 m a p a r t w i t h i n p l o t s , a l o n g t h e c e n t e r l i n e , and 7 m i n f r o m e a c h edge. One LI-COR LI-190SB quantum s e n s o r was shaded and u s e d t o m o n i t o r d i f f u s e p h o t o s y n t h e t i c p h o t o n f l u x d e n s i t y r a d i a t i o n (PPFD; 0.4-0.7 Mm) i n t h e p l o t c e n t e r as 3-minute a v e r a g e s o f 1-minute s a m p l e s . D i f f u s e open PPFD was e m p i r i c a l l y c a l c u l a t e d f r o m a c a l i b r a t i o n e q u a t i o n . D i r e c t r a d i a t i o n was o b t a i n e d by s u b t r a c t i n g t h e d i f f u s e r a d i a t i o n component f r o m g l o b a l r a d i a t i o n . T r a n s m i s s i o n o f e a c h component was computed by d i v i d i n g t h e a v e r a g e d a i l y sum of t h e two b e l o w - c a n o p y s e n s o r s by t h e d a i l y sum o f open r a d i a t i o n . O n l y d a y s t h a t were c l e a r were u s e d f o r a n a l y s e s . E a c h p l o t was m o n i t o r e d f o r a t l e a s t one f u l l d a y . B e c a u s e v a r i a b l e w e ather c o n d i t i o n s d i d n o t a l w a y s p e r m i t m o n i t o r i n g a p l o t d u r i n g one f u l l c l e a r day, h a l f - d a y m o n i t o r i n g ( s u n r i s e t o s o l a r noon) was m u l t i p l i e d by 2 f o r two c a s e s . T r a n s m i s s i o n was a v e r a g e d f o r p l o t s s a m p l e d o v e r two d a y s . R e g r e s s i o n e q u a t i o n s were d e v e l o p e d f o r s a l a l a b u n d a n c e s ( d e n s i t y , DENSITY; b a s a l a r e a , SALALBA; f o l i a r p r o d u c t i v i t y , CAGBIOM; t o t a l b i o m a s s , TOTBIOM; and c o v e r , PCTCOVER) as a f u n c t i o n o f t r a n s m i s s i o n o f e a c h r a d i a t i o n component u s i n g t h e r e g r e s s i o n e q u a t i o n : where Y i s t h e s a l a l v a r i a b l e , X i s t h e p r o p o r t i o n o f a r a d i a t i o n component t r a n s m i t t e d , a i s t h e r a t e a t w h i c h an a s y m p t o t e i s r e a c h e d , b i s t h e l e v e l o f t h e a s y m p t o t e , and c i s t h e l e v e l o f X where Y i s 0. T h i s f o r m of t h e e q u a t i o n i s a M i c h a e l i s - M e n t e n t y p e r e l a t i o n s h i p and g i v e s a f o r m s i m i l a r t o t h e s a t u r a t i o n c u r v e of p h o t o s y n t h e s i s w i t h i n c r e a s i n g l i g h t i n t e n s i t y t h a t i s o f t e n u s e d i n m o d e l i n g p h o t o s y n t h e s i s ( T h o r n l e y 1976). P a r a m e t e r e s t i m a t e s were o b t a i n e d u s i n g a n o n l i n e a r r e g r e s s i o n , d e r i v a t i v e - f r e e p a r a m e t e r - e s t i m a t i n g FORTRAN s u b r o u t i n e (Moore 1984). S t a n d a r d e r r o r of t h e e s t i m a t e x ) and i n d e x o f d e t e r m i n a t i o n (/*: E z e k i e l and Fox 1970) were computed f o r e a c h r e g r e s s i o n w i t h a FORTRAN p r o g r a m . • 92 RESULTS S a l a l e s t i m a t e s r a n g e d from 0.12-144.3 s h o o t s « m " 2 f o r d e n s i t y , 0.01-14.0 c m 2 « m " 2 f o r b a s a l a r e a , 0.06-634 g « m " 2 f o r b i o m a s s , 0.006-64.7 g » m " 2 f o r f o l i a r p r o d u c t i v i t y , 23-75 cm f o r a v e r a g e s h o o t h e i g h t , and 0.26-0.54 cm f o r a v e r a g e s h o o t b a s a l d i a m e t e r ( T a b l e 4 . 2 ) . Ranges o f t h e p r o p o r t i o n s o f r a d i a t i o n components t r a n s m i t t e d were 0.026-0.57 f o r g l o b a l , 0.18-1.80 f o r d i f f u s e , 0.005-0.43 f o r d i r e c t , and 0.01-0.29 f o r d i f f u s e PPFD ( T a b l e 4 . 3 ) . The p r o p o r t i o n of d i f f u s e r a d i a t i o n i n c l u d e d w i t h i n - c a n o p y s c a t t e r i n g o f d i r e c t beam and was n ot t h e t r u e p r o p o r t i o n of d i f f u s e s ky r a d i a t i o n t r a n s m i t t e d . S t a n d s t r u c t u r e i n t h e CWHb c a u s e d some p r o p o r t i o n s o f d i f f u s e r a d i a t i o n t r a n s m i t t e d t o be g r e a t e r t h a n 1.0 ( s e e C h a p t e r 3 ) . D a i l y maxima and a v e r a g e f l u x d e n s i t i e s o f s o l a r r a d i a t i o n below t h e c a n o p i e s a r e summarized ( T a b l e 4 . 3 ) . Form of response S a l a l a b u n d a n c e s were c l o s e l y r e l a t e d t o p r o p o r t i o n s o f t h e r a d i a t i o n components t r a n s m i t t e d w i t h i n and a c r o s s s u b z o n e s ( T a b l e 4 . 4 ) . The r e s p o n s e o f a l l s a l a l a b u n d a n c e s t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , and d i f f u s e PPFD were n o n l i n e a r , i n c r e a s i n g a s y m p t o t i c a l l y ( F i g s . 4 . 1 - 4 . 3 ) . The r e s p o n s e o f s a l a l t o t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n i n c r e a s e d n o n l i n e a r l y w i t h e i t h e r no o r an u n r e a l i s t i c a l l y h i g h upper a s y m p t o t e ( F i g s . 4.1-4.3; T a b l e 4 . 4 ) . D i f f u s e T A B L E 4 . 2 P l o t m e a n s a n d 9 5 % c o n f i d e n c e i n t e r v a l s f o r s a l a l c h a r a c t e r i s t i c s P l o t D E N S I T Y U-m--')a C A G B I O M (g-m-;)a T O T B I O M (gnr' ) a x C o n f . i n t . x C o n f . i n t . x C o n f . i n t . 1 0 . 7 0 . 1 - 1 . 7 0 . 0 2 0 . 0 - 0 . 1 0 . 2 3 0 . 0 - 1 . 0 2 1 0 . 8 6 . 9 - 1 5 . 7 2 . 1 3 1 . 0 - 3 . 9 2 0 . 0 7 1 0 . 0 - 3 5 . 2 5 2 8 . 2 2 3 . 6 - 3 3 . 2 2 8 . 1 3 2 0 . 0 - 3 8 . 2 2 7 1 . 0 7 1 8 9 . 4 - 3 7 3 . 3 6 1 6 . . 5 1 2 . 8 - 2 0 . 6 2 5 . 5 6 1 5 . . 1 - 3 9 . 9 4 0 0 . 2 8 2 4 2 . 9 - 6 1 4 . 0 7 6 8 . . 0 5 7 . 2 - 7 9 . 8 6 4 . . 6 5 5 0 . . 4 - 8 1 . 4 6 3 3 . . 5 7 4 6 6 . 9 - 8 3 5 . 8 9 0 . . 1 0 . 0 - 0 . 4 0 . . 0 1 0 . . 0 - 0 . 0 0 . . 0 6 0 . 0 - 0 . 3 2 1 1 0 2 . . 1 8 5 . . 5 - 1 2 0 . 6 3 6 . . 4 8 3 0 . . 9 - 4 2 . 7 2 7 8 . . 0 7 2 1 1 . . 9 - 3 5 6 . . 7 2 2 1 4 4 . . 5 1 2 4 . . 9 - 1 6 5 . . 5 5 5 . . 5 9 4 5 . 8 - 6 6 . . 6 2 8 9 . 17 2 1 6 . . 7 - 3 7 6 . . 1 2 3 1 2 . . 7 8 . , 6 - 1 7 . . 7 3 . . 3 3 1 . 8 - 5 . . 5 9 2 . 6 1 4 6 . . 3 - 1 6 2 . , 4 2 4 5 0 . 4 3 7 . . 9 - 6 4 . . 8 1 9 . 3 8 1 3 . 6 - 2 6 . . 5 1 6 5 . 1 5 1 0 5 . , 6 - 2 4 3 , , 6 2 6 5 . 7 2 . . 9 - 9 . . 3 0 . 5 8 0 . 2 - 1 . 2 7 . 2 2 2 . 6 - 1 5 . . 3 2 7 4 0 . 0 2 9 . 2 - 5 2 . . 5 1 3 . 9 9 8 . 9 - 2 0 . 8 2 2 6 . 9 6 1 3 9 . 3 - 3 4 5 . . 2 P C T C O V E R ( % ) b H E I G H T (cm)c B a s a l d i a . (cm)c x C o n f . i n t . x C o n f . i n t . n x C o n f . i n t . 0 . 4 0 . 1 - 1 . 0 2 5 . 3 1 8 . 9 - 3 2 . 5 4 4 0 . 2 1 0 . 2 8 - 0 . 2 4 9 . 6 6 . 2 - 1 3 . 6 2 3 . 8 2 1 . 1 - 2 6 . 6 2 0 9 0 . 2 6 0 . 2 4 - 0 , . 2 8 5 1 . 1 4 3 . 8 - 5 9 . 0 4 7 . 2 4 3 . 4 - 5 1 . 1 3 5 4 0 . 3 9 0 . 3 7 - 0 . . 4 1 3 8 . 5 3 2 . 8 - 4 4 . 6 7 4 . 8 6 7 . 5 - 8 2 . 6 2 3 7 0 , . 5 4 0 . 4 9 - 0 . . 5 9 5 0 . 3 4 3 . . 5 - 5 7 . 6 4 3 . . 1 4 0 . 9 - 4 5 . 4 8 8 1 0 , . 4 1 0 , . 3 9 - 0 , . 4 2 0 , , 1 0 . , 0 - 0 , . 2 3 4 , . 8 2 4 . 0 - 4 7 . 5 1 2 0 , . 3 4 0 , . 2 6 - 0 . 4 4 5 2 , , 9 4 5 . , 7 - 6 0 . , 5 2 7 , . 2 2 6 . 1 - 2 8 , . 3 1 2 9 4 0 . . 3 0 0 . , 2 9 - 0 . 3 0 4 8 . . 7 4 0 . . 4 - 5 7 . . 7 2 2 . 6 2 1 . . 8 - 2 3 . , 4 1 7 5 0 0 . , 3 1 0 . , 3 1 - 0 . 3 2 1 2 . . 2 7 . . 7 - 1 7 . , 8 4 3 . . 3 3 7 . . 9 - 4 9 . . 1 2 0 9 0 . 3 7 0 . , 3 5 - 0 . 4 0 3 3 . 5 2 5 . 8 - 4 2 . 3 3 2 . 3 3 0 . . 5 - 3 4 . , 1 6 8 0 0 . 3 0 0 . 2 9 - 0 . 3 1 2 . 6 1 . 2 - 4 . 5 2 4 . 3 2 0 . . 8 - 2 8 . 0 1 2 6 0 . 2 7 0 . 2 5 - 0 . 3 0 2 6 . 6 2 0 . 6 - 3 3 . 4 4 3 . 9 4 1 . . 6 - 4 6 . , 2 6 0 8 0 . 3 4 0 . 3 3 - 0 . 3 5 a A v e r a g e o f 5 2 0 . 2 5 m ! q u a d r a t s x 4 . A v e r a g e o f 5 2 0 . 2 5 m ! q u a d r a t s . A v e r a g e o f a l l s h o o t s m e a s u r e d . S e e n f o r s a m p l e s i z e s . T A B L E 4.3 Below-canopy s o l a r r a d i a t i o n s t a t i s t i c s P l o t GLOBAL DIRECT DIFFUSE PPFD 3 Max (Wm X -«) b P.T. Max (W-tn-X n P.T. Max (Wm-X ') P.T. Max („E m X -' s- 1 P.T. ) 1 c 90 15 0 .026 75 4 0 .008 26 10 0 . 177 5 1 .6 0 .010 2 810 35 0 .074 779 23 0 .053 33 12 0 .360 9 4.5 0 .050 5 d 720 31 0 .073 676 16 0 .046 64 16 0 .260 35 11.9 0 .069 6 750 41 0 .091 710 22 0 .058 43 19 0 .286 40 15.9 0 .088 7 e 940 200 0 .465 860 165 0 .429 96 35 0, . 775 104 43 . 1 0 .286 9 C 600 20 0 .040 579 6 0 .013 34 14 0. 310 9 1 .4 0, .01 1 21 890 129 0 .277 690 54 0 . 127 215 75 1 . ,429 98 38 . 3 0 . 261 22 990 250 0 . 566 846 164 0. ,416 165 86 1 . 799 66 28.7 0, .216 2 3 C 120 27 0. .058 78 96 0. .006 65 24 0. 569 9 4.3 0. .036 24 350 62 0. . 135 272 15 0. ,035 140 47 1 . 153 26 12.7 0. ,112 26 100 17 0. ,035 84 2 0. 005 30 15 0. 338 4 2.0 0. 016 27 560 65 0. 142 438 17 0. 039 120 48 1. 293 21 8.3 0. 080 a D i f f u s e p h o t o s y n t h e t i c photon f l u x d e n s i t y . ^ P r o p o r t i o n of above-canopy r a d i a t i o n t r a n s m i t t e d . c A v e r a g e of m o n i t o r i n g f o r two days. Computed from m o n i t o r i n g one f u l l day and one h a l f - d a y . Computed from m o n i t o r i n g one h a l f - d a y . TABLE 4 . * R e g r e s s i o n c o e f f i c i e n t s of e q u a t i o n s p r e d i c t i n g s a l a l v a r i a b l e s from s o l a r r a d i a t i o n components. Sample s i z e s : CWHa«6, CWHb-6. E q u a t i o n s s i g n i f i c a n t a t p < 0.06. R e g r e s s i o n e q u a t i o n : Y = -j—+ "a|x-c )/b Y Subzone X a b c / 2 s y X DENSITY: CWHa GLOBAL 418.8 108. 1 0. 0290 0. 93 7. 5 DIRECT 495.5 1 00. 6 0. 0083 0. 93 7 . 4 DIFFUSE 1 .3 - 3 . 4 - 1 . 7280 0. 83 1 1 . 7PPFD 324.0 273. 7 0. 0081 0. 95 6. 1 CWHb GLOBAL 559.4 288. 9 0. 0315 0. 98 7. 5 DIRECT 1686.3 183. 5 - 0 . 0002 0. 99 5. 8 DIFFUSE 35 .5 - 8 7 . 1 0. 2575 0. 93 16. 4 PPFD 776 .6 369. 9 0. 0164 0. 87 22 . 2 Both GLOBAL 520.9 211. 1 0. 0317 0. 86 17. 9 DIRECT 1054.4 146. 0 0. 0033 0. 7 1 25 . 3 DIFFUSE 72 .9 221167. 7 0. 1811 0. 80 21 . 2 PPFD 682.0 246. 6 0. 0163 0. 76 23 . 2 SALALBA: CWHa GLOBAL 122.8 19. 3 0. 0324 0. 88 2. 2 DIRECT 140.7 18. 4 0. 0104 0. 85 2. 4 DIFFUSE 0.2 - 0 . 6 - 2 . ,5214 0. 69 3. 5 PPFD 103.3 28. .6 0. ,0139 0. 94 1 . 5 CWHb GLOBAL 53.4 24. ,2 0. ,0255 0. ,99 0. ,3 DIRECT 159.5 16. ,2 - 0 . ,0027 0. ,99 0. ,5 DIFFUSE 3.1 - 8 . , 1 0. .1737 0. ,96 1 . , 1 PPFD 80 .7 24. ,8 o. .0127 0. ,85 2. , 1 Both GLOBAL 71 .0 21 . 3 0. .0257 0. ,89 1 . ,7 DIRECT 134.4 17. .9 0. .0020 0. ,89 1 . 7 DIFFUSE 5.7 8804. ,0 - 0 . .1711 0. .40 4 . 0 PPFD 87 .2 27. .2 0. .0127 0. .88 1 . .8 TOTBIOM: CWHa GLOBAL 6631.0 829, .5 0, .0325 0, .82 125. .7 DIRECT 7730.0 790, .7 0, .0106 0, .79 1 35. .2 DIFFUSE N.S." PPFD 5665.0 1119, .3 0, .0141 0, .90 91 . 9 CWHb GLOBAL 4758.0 337, .3 0, .0330 0, .97 22. ,7 DIRECT 16027.0 309, . 1 0, .0016 0, .92 34. .5 DIFFUSE 196.6 -547155 . 0, .1992 0, .94 29. .2 PPFD 6241.0 343, .5 0, .0151 0. .92 35. .3 Both GLOBAL 5277.0 497, .8 0, .0307 0, .60 128. .4 DIRECT 7405.0 531 , .7 0, .0027 0, .63 122. .4 DIFFUSE N.S. PPFD 4679.0 . 655, .3 0, .0123 0, ,6B 114. .8 CAGBIOM: CWHa GLOBAL 476.8 94, .6 0, .0320 0, .88 9. .9 DIRECT 537.2 90, .6 0, .0098 0, .86 10. .6 DIFFUSE 0 .6 -2 , .3 -2 , .6543 0. .73 14. .6 PPFD 406. 1 1 57, .8 0, .0139 0, .94 7. , 1 CWHb GLOBAL 204.6 1 16, .5 0, .0374 0. .99 2. ,6 DIRECT 603.2 71 , .3 0, .0016 0. .99 2. .6 DIFFUSE 14.4 -33 , .2 0, .3522 0. .94 5. ,9 PPFD 317.6 120, .7 0, .0219 0. .84 9. .3 Both GLOBAL 245.3 1 13, . 1 0, .0254 0. .86 8. .7 DIRECT 523.7 82. .9 0, .0044 0, .90 7. .4 DIFFUSE 23.3 899135, .0 - 0 , . 1637 0. .33 19. ,0 PPFD 317.5 162, .3 0, .0148 0. .86 8. .7 PCTCOVER: CWHa GLOBAL 1245.0 58, .6 0, .0294 0. .64 16. .3 DIRECT 1879.0 53, .9 0, .0098 0. .65 16. .0 DIFFUSE N.S. PPFD 1202.0 63, .6 0, .0111 0. .79 12. ,5 CWHb GLOBAL 620. 1 62. .9 0, .0318 0. .93 5. .7 DIRECT 2096.0 55.8 0.0013 0, .93 5. ,9 DIFFUSE 44 .5 210, .6 0, .2818 0. .87 B. .0 PPFD 557.8 84, .9 0. .0113 0. .99 0. ,2 Both GLOBAL 984.5 56, .9 0, .0303 0. .73 1 1 . ,6 DIRECT 1651.0 56, .6 0, .0040 0. .72 1 1 . ,8 DIFFUSE N.S. PPFD 905.3 66 .7 0, .0121 0, .85 8. ,7 °Equation not s i g n i f i c a n t (p i 0 . 0 6 ) . o.e 01 0 5 oa 0.4 o.a o.a P R O P O R T I O N G L O B A L . R A D I A T I O N T R A N S M I T T E D (To 0.1 OJ OS 04 >^.B P R O P O R T I O N DIRECT R A D I A T I O N T R A N S M I T T E D F i g u r e 4.1. R e l a t i o n s h i p s o f s a l a l b a s a l a r e a (cm 2'm~ 2) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c o mponents. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffl). 97 oo o.a o.« o.e o.a to o 1« to i t PROPORTION DIFFUSE RADIATION TRANSMITTED oo oi O J o.a PROPORTION DIFFUSE PPFD TRANSMITTED F i g u r e 4.2. R e l a t i o n s h i p s o f s a l a l f o l i a r p r o d u c t i v i t y ( g » m ~ 2 ; CAGBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n o f g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n components. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffi). lOOO.O-i _ 000 .0 -PROPORTION GLOBAL RADIATION TRANSMITTED 1000.0-i 000 .0 -•oo.o-PROPORTION DIRECT RADIATION TRANSMITTED i g u r e 4.3. R e l a t i o n s h i p s of s a l a l t o t a l b i o m a s s ( g « m ~ 2 ; TOTBIOM) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c o mponents. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffl). 99 i r r a d i a n c e s u nder c a n o p i e s were low ( T a b l e 4 . 3 ) . When a v e r a g e d a i l y i r r a d i a n c e o f g l o b a l and d i f f u s e r a d i a t i o n below t h e c a n o p y were a b o u t e q u a l ( e . g . , g l o b a l p l o t 1 and d i f f u s e p l o t 5, p l o t s 23 o r 26 i n T a b l e 4.3) t h e p r o p o r t i o n o f d i f f u s e t r a n s m i t t e d was a b o u t 10x t h a t o f g l o b a l . A l t h o u g h s a l a l showed an a l m o s t u n l i m i t e d i n c r e a s e w i t h t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n , s a l a l a p p a r e n t l y a p p r o a c h e d an a s y m p t o t e w i t h i n c r e a s i n g p r o p o r t i o n of d i f f u s e PPFD t r a n s m i t t e d ( T a b l e 4.4; F i g s . 4 . 1 - 4 . 3 ) . B e l o w - c a n o p y d i f f u s e r a d i a t i o n was low i n PPFD ( C h a p t e r 3) b e c a u s e o f a b s o r p t i o n by t h e f o r e s t c a n o p y . The amount o f PPFD i n b e l o w - c a n o p y d i f f u s e r a d i a t i o n , however, i n c r e a s e d w i t h i n c r e a s i n g p r o p o r t i o n o f PPFD t r a n s m i t t e d ( C h a p t e r 3 ) . Salal s hoot size The r e l a t i o n s h i p of s a l a l s h o o t s i z e ( h e i g h t and b a s a l d i a m e t e r ) t o t r a n s m i s s i o n of g l o b a l and d i r e c t r a d i a t i o n ( F i g . 4.4) showed 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 t h e CWHa, p r o b a b l y due t o s i t e and age d i f f e r e n c e s . A s l i g h t r e l a t i o n s h i p was f o u n d i n t h e CWHb s t a n d of t h e same age, d e s p i t e a narrow r a n g e o f s h o o t s i z e s . At t h e l o w e s t t r a n s m i s s i o n s h o o t s were s m a l l . As t r a n s m i s s i o n i n c r e a s e d , s h o o t h e i g h t and d i a m e t e r were l a r g e r , but as t r a n s m i s s i o n f u r t h e r i n c r e a s e d , h e i g h t and b a s a l d i a m e t e r d e c r e a s e d . The r e l a t i o n s h i p s were more p r o n o u n c e d f o r h e i g h t t h a n f o r b a s a l d i a m e t e r . S a l a l s h o o t s i z e was a d v e r s e l y a f f e c t e d by h i g h t r a n s m i s s i o n o f s o l a r r a d i a t i o n . S h o o t s were p r o d u c t i v e , 100 100.0- 100.0-80.0- 00.0-eo.o- eo.o-< 40.0- 40.0-E z o o - . 20.0--0.0-0.0 0.1 O.J 0.3 0.4 o.e o.e PROPORTION GLOBAL RADIATION TRANSMITTED 0.0 0.1 0.2 0.3 0.4 O.S PROPORTION DIRECT RADIATION TRANSMITTED E 0.6 0.4 0.3-0.2-0.1 m i i 0.0 0.1 0.2 0.3 0.4 0.6 PROPORTION G L O B A L RADIATION TRANSMITTED 0.6 0.3 o.i-i I i B m Q $ 0.0-0.0 0.1 0.2 0.8 0.4 0.6 PROPORTION DIRECT RADIATION TRANSMITTED F i g u r e 4 . 4 . R e l a t i o n s h i p s o f a v e r a g e s h o o t h e i g h t (cm) and b a s a l d i a m e t e r (cm) of s a l a l w i t h 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l a nd d i r e c t r a d i a t i o n . CWHa (•), CWHb (ffl). 101 however, under open c a n o p i e s w i t h h i g h t r a n s m i t t a n c e ( F i g . 4 . 5 ) . Subzone differences A q u a l i t a t i v e a s s e s s m e n t was made o f p o t e n t i a l d i f f e r e n c e s o f e q u a t i o n s between s u b z o n e s b e c a u s e no t e s t s were a v a i l a b l e f o r t h e f o r m o f r e g r e s s i o n e q u a t i o n u s e d . E q u a t i o n s d i f f e r e d s t r o n g l y i n a l l c a s e s where s a l a l was p r e d i c t e d by d i f f u s e r a d i a t i o n ( e . g . , F i g s . 4.1-4.3; T a b l e 4 . 4 ) . D i f f e r e n c e s between t h e e q u a t i o n s were due t o d i f f e r e n c e s i n s t a n d s t r u c t u r e between t h e s u b z o n e s and t h e d i f f e r e n t way i n w h i c h d i f f u s e r a d i a t i o n was t r a n s m i t t e d ( s e e C h a p t e r 3 F i g . 3 . 2 ) . Any s i t e e f f e c t s t h a t would have c o n t r i b u t e d t o d i f f e r e n c e s i n s a l a l between t h e s u b z o n e s were masked by t h e d i f f e r e n t i a l t r a n s m i s s i o n of d i f f u s e r a d i a t i o n between t h e two s t a n d s t r u c t u r e s . The manner i n w h i c h r a d i a t i o n i s t r a n s m i t t e d by d i f f e r e n t s t a n d s t r u c t u r e s and t h e e f f e c t s of s t a n d age and s i t e q u a l i t y i n t e r a c t t o a f f e c t r e g r e s s i o n c o e f f i c i e n t s . Among s t a n d s , maximum abundance o f s a l a l f o r a g i v e n p r o p o r t i o n o f r a d i a t i o n t r a n s m i t t e d would l i k e l y be r e g u l a t e d by s i t e and age e f f e c t s . The r a t e a t w h i c h a maximum i s r e a c h e d ( c o e f f i c i e n t a) and upper a s y m p t o t e ( c o e f f i c i e n t b) a r e r e g u l a t e d by an i n t e r a c t i o n o f t h e way i n w h i c h r a d i a t i o n i s t r a n s m i t t e d ( s t a n d s t r u c t u r e s ) and s i t e and age e f f e c t s . A l t h o u g h d i f f e r e n c e s between s u b z o n e s a r e d i s c u s s e d , t h e p o t e n t i a l s ubzone e f f e c t s t h a t m i g h t c a u s e e q u a t i o n s t o be d i f f e r e n t a r e 102 > 0 D Q O t r Q. fe O X CO UJ o < cc 1X1 5 1.75-1 O O JZ w 3 1.60 H 1.25-1.00-0.75-0.50-0.00 0.25-j ^ • ' ^ -ffl 0.6 0.0 0.1 0.2 0.3 0.4 0.5 PROPORTION GLOBAL RADIATION TRANSMr TED 1.75-1 o o JZ w 3 1.50 H > F u 3 Q O C C C L fe O X to UJ < CC UJ 5 125-1.00-0.75-0.50-025 0.00 -83-I I I I 1 0.0 0.1 02 0.3 0.4 0.5 PROPORTION DIRECT RADIATION TRANSMITTED F i g u r e 4 . 5 . R e l a t i o n s h i p s o f a v e r a g e p r o d u c t i v i t y o f s a l a l s h o o t s t o t r a n s m i s s i o n o f g l o b a l and d i r e c t s o l a r r a d i a t i o n . CWHa (•), CWHb (ff l) . 103 c o n f o u n d e d by b r o a d d i f f e r e n c e s i n s t a n d s t r u c t u r e and t r a n s m i s s i o n between t h e two s u b z o n e s . E q u a t i o n s p r e d i c t i n g s a l a l d e n s i t y and t o t a l b i o m a s s p e r u n i t a r e a f r o m t r a n s m i s s i o n o f g l o b a l , d i r e c t a nd d i f f u s e PPFD r a d i a t i o n d i f f e r e d between s u b z o n e s ( e . g . , F i g . 4.3; T a b l e 4 . 4 ) . Maximum d e n s i t y was c o n s i d e r a b l y l o w e r i n t h e CWHa t h a n i n t h e CWHb and maximum t o t a l b i o m a s s was much g r e a t e r i n t h e CWHa. S l o p e s ( c o e f f i c i e n t a) a l s o d i f f e r e d s t r o n g l y ( T a b l e 4 . 4 ) . S i t e and age e f f e c t s r e s u l t e d i n a l o w e r d e n s i t y ( T a b l e 4.4) o f l a r g e r s h o o t s ( F i g . 4.4) i n t h e CWHa. B e c a u s e i n d i v i d u a l s h o o t b i o m a s s i s a l l o m e t r i c a l l y r e l a t e d t o s h o o t s i z e , a s m a l l c hange i n s h o o t s i z e w ould g i v e a p r o p o r t i o n a t e l y g r e a t e r change i n s h o o t b i o m a s s . A l t h o u g h p l c t t 7 d e n s i t y was l e s s t h a n o n e - h a l f t h a t o f p l o t 22's ( T a b l e 4 . 2 ) , a v e r a g e s h o o t b i o m a s s i n p l o t 7 was more t h a n q u a d r u p l e t h a t o f s h o o t s i n p l o t 22. D i f f e r e n c e s i n e q u a t i o n s p r e d i c t i n g s a l a l b a s a l a r e a , f o l i a r p r o d u c t i v i t y , and p e r c e n t c o v e r from t r a n s m i s s i o n o f g l o b a l , d i r e c t , and d i f f u s e PPFD r a d i a t i o n were l e s s p r o n o u n c e d . The subzone h a v i n g t h e l a r g e s t c o e f f i c i e n t b f o r SALALBA and CAGBIOM and g r e a t e s t m a g n i t u d e o f d i f f e r e n c e o f c o e f f i c i e n t a d i f f e r e d among t h e r a d i a t i o n c omponents. E q u a t i o n s p r e d i c t i n g SALALBA, CAGBIOM, and PCTCOVER from t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d g e n e r a l l y d i d n o t d i f f e r . T r a n s m i s s i o n of d i r e c t r a d i a t i o n d i d n o t d i f f e r between t h e s u b z o n e s ( C h a p t e r 3 ) . A l t h o u g h i n d i v i d u a l s h o o t p r o d u c t i v i t y a nd b a s a l a r e a i n t h e CWHa p l o t 7 was abo u t t w i c e 1 04 t h a t o f CWHb p l o t 22 ( F i g . 4 . 5 ) , d e n s i t y was a b o u t o n e - h a l f and t h e r e f o r e SALALBA a n d CAGBIOM p e r u n i t a r e a were s i m i l a r i n t h e two s u b z o n e s ( T a b l e 4.2; F i g s . 4.1 and 4 . 2 ) . B e c a u s e t r a n s m i s s i o n o f d i r e c t r a d i a t i o n between t h e s t a n d s t r u c t u r e s and s a l a l abundance were s i m i l a r , e q u a t i o n s d i d n o t d i f f e r . E q u a t i o n s p r e d i c t i n g SALALBA, CAGBIOM, and PCTCOVER f r o m t h e p r o p o r t i o n o f g l o b a l and d i f f u s e PPFD r a d i a t i o n a p p e a r e d t o d i f f e r ( e . g . , F i g s . 4.1 and 4.2), l i k e l y due, i n p a r t , t o p o t e n t i a l d i f f e r e n c e s i n t h e way t h e s e r a d i a t i o n components were t r a n s m i t t e d ( C h a p t e r 3 ) . A d d i t i o n a l l y , g l o b a l a n d d i f f u s e PPFD c o n t a i n d i f f u s e r a d i a t i o n w h i c h was t r a n s m i t t e d v e r y d i f f e r e n t l y by t h e two s t a n d s t r u c t u r e s . The f o r m of t h e r e l a t i o n s h i p s o f s a l a l s h o o t s i z e ( F i g . 4.4) and s h o o t p r o d u c t i v i t y ( F i g . 4.5) t o t r a n s m i s s i o n o f r a d i a t i o n d i d n o t d i f f e r s u b s t a n t i a l l y between s u b z o n e s . A b s o l u t e v a l u e s f o r a g i v e n p r o p o r t i o n t r a n s m i t t e d d i f f e r e d p r o b a b l y b e c a u s e o f s i t e and age e f f e c t s . Relative predictability among radiation components A l t h o u g h t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n w o u l d p r e d i c t u n r e a l i s t i c a l l y h i g h r e g r e s s i o n e s t i m a t e s o f s a l a l a bundance a t p r o p o r t i o n s t r a n s m i t t e d b eyond what was f o u n d h e r e , t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n d i d a d e q u a t e l y p r e d i c t s a l a l a bundance i n t h e CWHb (i2 = 0.87-0.96). R e l a t i o n s h i p s u s i n g d i f f u s e r a d i a t i o n i n t h e CWHa were p o o r e r t h a n u s i n g o t h e r c o mponents. R e s u l t s between t h e s u b z o n e s d i f f e r e d , w i t h PPFD p r e d i c t i n g a l l s a l a l a b u n d a n c e s b e t t e r t h a n o t h e r components 105 i n t h e CWHa, but PPFD g e n e r a l l y had a l o w e r p r e d i c t a b i l i t y t h a n o t h e r components i n t h e CWHb. T r a n s m i s s i o n o f PPFD was more c l o s e l y r e l a t e d t o f o r e s t s t a n d c h a r a c t e r i s t i c s i n t h e CWHa t h a n i n t h e CWHb ( C h a p t e r 3 T a b l e 3 . 3 ) . S a l a l a b u n d a n c e s were b e t t e r p r e d i c t e d by t r a n s m i s s i o n o f g l o b a l a nd d i r e c t r a d i a t i o n i n t h e CWHb t h a n i n t h e CWHa even t h o u g h t r a n s m i s s i o n o f g l o b a l and d i r e c t r a d i a t i o n were b e t t e r p r e d i c t e d by s t a n d c h a r a c t e r i s t i c s i n t h e CWHa ( C h a p t e r 3 T a b l e s 3.3 and 3. 4 ) . The l a c k o f s i t e v a r i a t i o n i n t h e CWHb may have c o n t r i b u t e d t o t h e b e t t e r p r e d i c t a b i l i t i e s . SALALBA, CAGBIOM, and PCTCOVER were p r e d i c t e d a b o u t e q u a l l y w e l l by g l o b a l and d i r e c t r a d i a t i o n f o r c o m b i n e d e q u a t i o n s . D e n s i t y , t o t a l b i o m a s s , and c o v e r a l s o were p r e d i c t e d a b o u t e q u a l l y w e l l by t r a n s m i s s i o n of g l o b a l and d i r e c t r a d i a t i o n i n i n d i v i d u a l s u b z o n e s . Effects of radiation components on salal S a l a l a b u n d a n c e s c o n s i s t e n t l y r e a c h e d u p p e r a s y m p t o t e s f a s t e r f o r t r a n s m i s s i o n of d i r e c t r a d i a t i o n t h a n f o r o t h e r components ( c o e f f i c i e n t a, T a b l e 4.4; F i g s . 4 .1-4.3). S a l a l maxima were c o n s i s t e n t l y l o w e r f o r t r a n s m i s s i o n o f d i r e c t r a d i a t i o n ( c o e f f i c i e n t b, T a b l e 4.4), and t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d a t l e v e l s o f s a l a l n e a r z e r o was g e n e r a l l y l e s s t h a n f o r g l o b a l o r PPFD ( c o e f f i c i e n t c, T a b l e 4 . 4 ) . T h e s e r e s u l t s s u g g e s t t h a t s a l a l i s more c l o s e l y r e g u l a t e d by t r a n s m i s s i o n o f t h e d i r e c t r a d i a t i o n component t h a n by o t h e r components. 106 DISCUSSION S a l a l d e n s i t y , b a s a l a r e a , b i o m a s s , p r o d u c t i v i t y p e r s h o o t and p e r u n i t a r e a , and c o v e r i n c r e a s e d a s y m p t o t i c a l l y w i t h i n c r e a s i n g p r o p o r t i o n s of g l o b a l , d i r e c t , and d i f f u s e p h o t o s y n t h e t i c p h o t o n f l u x d e n s i t y r a d i a t i o n ( F i g s . 4.1-4.3, 4 . 5 ) . The forms o f t h e r e l a t i o n s h i p s were s i m i l a r t o t h e a s y m p t o t i c r e l a t i o n s h i p o f p h o t o s y n t h e t i c r e s p o n s e t o l i g h t i n t e n s i t y . B e c a u s e d i f f u s e i r r a d i a n c e below c a n o p i e s was low, t h e r e l a t i o n s h i p s o f s a l a l a b u n d a n c e s t o t r a n s m i s s i o n o f d i f f u s e r a d i a t i o n were i n t h e l o w e r p h a s e o f t h e s a t u r a t i o n c u r v e . The d i f f e r e n c e between d i f f u s e PPFD and d i f f u s e s h o r t w a v e r e l a t i o n s h i p s d e m o n s t r a t e t h e i m p o r t a n c e o f m e a s u r i n g p h o t o n f l u x as o p p o s e d t o r e l a t i n g u n d e r s t o r y p l a n t g r o w t h t o d i f f u s e s h o r t w a v e s o l a r e n e r g y below a c a n o p y . The i n t e r a c t i o n of s o l a r r a d i a t i o n and i t s i n f l u e n c e on m o i s t u r e r e l a t i o n s i n s a l a l was d e m o n s t r a t e d by Swank ( 1 9 7 2 ) . He c o n c l u d e d t h a t s a l a l " s u n " p l a n t s were under g r e a t e r water s t r e s s f o r l o n g e r t i m e t h a n shade p l a n t s . Of t h r e e l i g h t i n t e n s i t i e s u s e d i n a g r e e n h o u s e e x p e r i m e n t (400, 1600, 2600 f . c ) , Swank (1972) f o u n d s a l a l p h o t o s y n t h e s i s t o be g r e a t e s t u n der t h e m i d - l i g h t i n t e n s i t y . L i g h t i n t e n s i t y u nder c a n o p i e s on sunny d a y s i n summer i s u s u a l l y l e s s t h a n 2000 f . c . The c o m b i n a t i o n o f h i g h l i g h t i n t e n s i t y and g r e a t e r w a t e r s t r e s s r e s u l t e d i n l o w e r e d n e t p h o t o s y n t h e t i c r a t e f o r " s u n " p l a n t s compared t o " s h a d e " p l a n t s . The r e s u l t s i n t h i s s t u d y i n d i c a t e d t h a t s h o o t s t h a t r e c e i v e d a h i g h p r o p o r t i o n o f 107 d i r e c t r a d i a t i o n were s m a l l e r ( p o s s i b l y b e c a u s e o f l o w e r e d p h o t o s y n t h e t i c r a t e o r m o i s t u r e s t r e s s ) t h a n s h o o t s t h a t r e c e i v e d l e s s r a d i a t i o n ( F i g . 4 . 4 ) . S h o o t p r o d u c t i v i t y , however, i n c r e a s e d a s y m p t o t i c a l l y ( F i g . 4 . 5 ) . A t low l i g h t i n t e n s i t y , Swank (1972) r e p o r t e d t h a t p h o t o s y n t h e s i s was l o w e s t . R e s u l t s h e r e f o u n d t h a t s h o o t s t h a t r e c e i v e d t h e l o w e s t p r o p o r t i o n o f r a d i a t i o n t r a n s m i t t e d were s m a l l e r and l e s s p r o d u c t i v e t h a n s h o o t s t h a t r e c e i v e d more r a d i a t i o n , l i k e l y b e c a u s e t h e r e was t o o l i t t l e l i g h t f o r a d e q u a t e g r o w t h . My r e s u l t s a r e a l s o c o n s i s t e n t w i t h t h e i d e a s o f W h i t e h e a d ( 1 9 7 3 ) . He d i s c u s s e d " c o m p e n s a t i o n " by p l a n t s g r o w i n g i n low l i g h t e n v i r o n m e n t s . P l a n t s compensate f o r low l i g h t by a l l o c a t i n g a s s i m i l a t e s t o l e a f m a t e r i a l , i n c r e a s i n g l e a f s i z e t o i n c r e a s e t h e a r e a o f p h o t o s y n t h e t i c t i s s u e , and t h u s e n s u r i n g t h a t t h e same amount o f c a r b o n i s f i x e d p e r u n i t t i m e as p l a n t s r e c e i v i n g more l i g h t . An e x p e n s e i s p a i d f o r c o m p e n s a t i o n by r e d u c e d r e p r o d u c t i v e s t r u c t u r e s . S a b h a s r i (1961) and B u n n e l l and K o c h - B a k k e r (1986) f o u n d t h a t s a l a l s h o o t s have more f l o w e r s i n open a r e a s t h a n under f o r e s t c a n o p i e s . D a t a a r e not a v a i l a b l e on s a l a l r e p r o d u c t i o n by r h i z o m e s i n open a r e a s and u n d e r c a n o p i e s . S a l a l r e c r u i t m e n t as measured by d e t e r m i n i n g s a l a l p o p u l a t i o n age s t r u c t u r e was g r e a t e r i n open, young c l e a r c u t a r e a s t h a n under o l d - g r o w t h f o r e s t c a n o p i e s (R.M. E l l i s , u n p u b l . d a t a , B.C. M i n i s t r y o f F o r e s t s , V i c t o r i a , B . C . ) . B u n n e l l and K o c h - B a k k e r (1986) f o u n d s a l a l " p l a n t s " i n open a r e a s had more s h o o t s t h a n " p l a n t s " under c a n o p i e s , even t h o u g h c a n o p y p l a n t s were o l d e r . 108 Boardman (1977) r e v i e w e d p h y s i o l o g i c a l d i f f e r e n c e s between sun and shade p l a n t s . He s t a t e d t h a t shade p l a n t s g e n e r a l l y have l o w e r l i g h t s a t u r a t i o n and c o m p e n s a t i o n l e v e l s , l o w e r d a r k r e s p i r a t i o n r a t e s , a r e r i c h e r i n c h l o r o p h y l l , have l o w e r s t o m a t a l d e n s i t y , and t h i n n e r l e a v e s . Sun p l a n t s w i t h t h i c k e r l e a v e s and h i g h e r d e n s i t y o f s t o m a t a have h i g h e r c o n d u c t a n c e s t o C 0 2 d i f f u s i o n and c o n s e q u e n t l y g r e a t e r C 0 2 f i x a t i o n . Swank (1972) f o u n d t h a t s a l a l l e a v e s f r o m sun p l a n t s were t h i c k e r t h a n shade p l a n t s , c o n s i s t e n t w i t h Boardman ( 1 9 7 7 ) . S a b h a s r i (1961) r e p o r t e d t h a t s a l a l sun p l a n t l e a v e s had a h i g h e r mass p e r u n i t s u r f a c e a r e a t h a n shade p l a n t l e a v e s . K e l l i h e r (1985) f o u n d s a l a l l e a f s i z e t o i n c r e a s e w i t h i n c r e a s i n g s t a n d b a s a l a r e a ( r e d u c e d p r o p o r t i o n o f r a d i a t i o n t r a n s m i t t e d , C h a p t e r 3 ) , c o n s i s t e n t w i t h W h i t e h e a d ' s (1973) o b s e r v a t i o n s . The r e l a t i o n s h i p between my s a l a l a v e r a g e l e a f masses by p l o t and p r o p o r t i o n s o f r a d i a t i o n t r a n s m i t t e d had a p r o n o u n c e d form o f r e l a t i o n s h i p s i m i l a r t o t h a t between s h o o t h e i g h t and p r o p o r t i o n s t r a n s m i t t e d . S a l a l l e a v e s i n shade a r e d a r k e r g r e e n t h a n i n open a r e a s . A l t h o u g h n o t e x amined i n t h i s s t u d y , i t i s l i k e l y t h a t s a l a l sun and shade p l a n t s have a p h y s i o l o g y c o n s i s t e n t w i t h t h e s p e c i e s r e v i e w e d by Boardman ( 1 9 7 7 ) . A p o s s i b l e a d d i t i o n a l e x p l a n a t i o n f o r t a l l e r s h o o t s under low t o m o d e r a t e p r o p o r t i o n s ' t r a n s m i t t e d c o u l d be due t o t h e e f f e c t s of n e a r i n f r a - r e d w a v e l e n g t h s (NIR) on stem e l o n g a t i o n . S a b h a s r i (1961) f o u n d t h a t s a l a l s h o o t l e n g t h was g r e a t e s t under r e d l i g h t . The s p e c t r a l c o m p o s i t i o n below a 109 c o n i f e r o u s f o r e s t canopy i s r i c h i n NIR ( F e d e r e r and T a n n e r 1966) and may s t i m u l a t e stem e l o n g a t i o n . E v a n s (1973) a l s o m e n t i o n e d t h a t e t i o l a t i o n c a u s e d stem e l o n g a t i o n i n o l d e r s h o o t s a t low l i g h t i n t e n s i t i e s . I t i s u n c l e a r w hether " c o m p e n s a t i o n " , m o i s t u r e s t r e s s , p h o t o s y n t h e t i c r a t e , o r NIR e n r i c h m e n t a l o n e c a n e x p l a i n t h e d i f f e r e n c e s i n s h o o t s i z e among d i f f e r e n t p r o p o r t i o n s t r a n s m i t t e d . A l t h o u g h s a l a l s h o o t s i z e and b i o m a s s p e r s h o o t were s m a l l e r a t t h e h i g h e s t p r o p o r t i o n s o f r a d i a t i o n t r a n s m i t t e d ( F i g . 4 . 4 ) , f o l i a r p r o d u c t i v i t y p e r s h o o t i n c r e a s e d ( F i g . 4 . 5 ) . The r a t e of i n c r e a s e i s most r a p i d w i t h a s m a l l i n c r e a s e i n t h e p r o p o r t i o n o f d i r e c t r a d i a t i o n t r a n s m i t t e d . A p p a r e n t l y s h o o t s i n t h e open do n o t a c c u m u l a t e much b i o m a s s , e i t h e r l o s i n g t h e i r l e a v e s r a p i d l y o r h a v i n g t w i g s d y i n g b a c k . L e a v e s may d i e back e a r l y b e c a u s e o f h i g h m o i s t u r e s t r e s s (Swank 1972). B e cause open-grown s a l a l i s p r o d u c t i v e , a s s i m i l a t e s may be a l l o c a t e d t o p r o d u c t i o n o f f l o w e r s and f r u i t ( S a b h a s r i 1961; B u n n e l l and K o c h - B a k k e r 1986) o r r e p r o d u c t i o n by r h i z o m e s ( B u n n e l l and K o c h - B a k k e r 1986; R.M. E l l i s , unpub.l. d a t a ) r e s u l t i n g i n h i g h s h o o t d e n s i t y . S a b h a s r i (1961) f o u n d t h a t r o o t l e n g t h was g r e a t e s t a t t h e h i g h e s t l i g h t i n t e n s i t y he u s e d (400 f . c ) . I n c r e a s e s i n s a l a l a b undance p e r u n i t a r e a were f o u n d w i t h i n c r e a s e d p r o p o r t i o n s t r a n s m i t t e d . W i t h i n a s u b z o n e t h e g r e a t e r d e n s i t y o f s h o o t s u n d e r open c a n o p i e s c o m p e n s a t e d f o r s m a l l e r s h o o t s t o g i v e an o v e r a l l i n c r e a s e i n b a s a l a r e a and b i o m a s s . S h o o t d e n s i t y i n open a r e a s may be h i g h b e c a u s e o f 1 10 i n c r e a s e d r e p r o d u c t i o n ( W h i t e h e a d 1973) a s was f o u n d by B u n n e l l and K o c h - B a k k e r (1986) and E l l i s ( u n p u b l . d a t a ) , o r r e d u c e d c o m p e t i t i o n f o r l i g h t among s h o o t s . Fewer s h o o t s a r e f o u n d u n d e r d e n s e r c a n o p i e s , p o s s i b l y b e c a u s e i n t r a - s p e c i f i c c o m p e t i t i o n c a u s e s t h i n n i n g , o r b e c a u s e l o w e r p r o p o r t i o n o f r a d i a t i o n t r a n s m i t t e d i s a s s o c i a t e d w i t h h i g h e r s t a n d d e n s i t i e s ( C h a p t e r 3 ) , and p o t e n t i a l i n t e r - s p e c i f i c c o m p e t i t i o n w i t h t r e e s f o r m o i s t u r e ( B l a c k e t a l . 1980) o r p o s s i b l y n u t r i e n t s (Weetman e t a l . 1986). A p p a r e n t d i f f e r e n c e s between e q u a t i o n s d e v e l o p e d i n i n d i v i d u a l s u b z o n e s c o u l d be a t t r i b u t e d t o t h e way r a d i a t i o n was t r a n s m i t t e d by d i f f e r e n t s t a n d s t r u c t u r e s ( C h a p t e r 3) and s i t e and age d i f f e r e n c e s . E q u a t i o n s d i f f e r e d s t r o n g l y w i t h d i f f u s e r a d i a t i o n a s an i n d e p e n d e n t v a r i a b l e , a n d a l l e q u a t i o n s d i f f e r e d w i t h d e n s i t y and t o t a l b i o m a s s a s de p e n d e n t v a r i a b l e s . W i t h i n a s t a n d , d e n s i t y and bio m a s s a r e a f f e c t e d by an i n t e r a c t i o n of s o l a r r a d i a t i o n ( T a b l e 4.4) and s t a n d d e n s i t y ( C h a p t e r 2 ) . Among s t a n d s , a s between t h e CWHa and CWHb, and w i t h i n t h e CWHa, maximum b i o m a s s and d e n s i t y may d i f f e r f o r a g i v e n p r o p o r t i o n o f r a d i a t i o n t r a n s m i t t e d o r s t a n d d e n s i t y , e i t h e r b e c a u s e o f age d i f f e r e n c e s , n u t r i t i o n ( e . g . , K e y e s and G r i e r 1981), o r s i t e water b a l a n c e ( G r i e r and R u n n i n g 1977; G h o l z 1982). W e t t e r s a l a l s i t e s on t h e west and n o r t h c o a s t of V a n c o u v e r I s l a n d s u p p o r t much l a r g e r s h o o t s t h a n a r e f o u n d on t h e d r i e r i n t e r i o r and e a s t e r n p a r t s o f t h e I s l a n d . 111 Subzone d i f f e r e n c e s were s l i g h t l y e v i d e n t f o r s a l a l b a s a l a r e a , p r o d u c t i v i t y , o r c o v e r p r e d i c t e d f r o m t r a n s m i s s i o n o f g l o b a l o r d i f f u s e PPFD. O n l y d i r e c t r a d i a t i o n showed no p r o n o u n c e d d i f f e r e n c e between s u b z o n e s f o r r e l a t i o n s h i p s p r e d i c t i n g s a l a l b a s a l a r e a , f o l i a r p r o d u c t i v i t y , o r c o v e r . A l l s a l a l v a r i a b l e s were p r e d i c t e d w e l l by most r a d i a t i o n components ( T a b l e 4 . 4 ) . T r a n s m i s s i o n o f d i r e c t r a d i a t i o n had t h e most i n f l u e n c e on s a l a l (maxima l o w e s t and r a t e of i n c r e a s e f a s t e s t ) . B e c a u s e t h e b e l o w - c a n o p y d i f f u s e r a d i a t i o n was low i n p h o t o n f l u x ( C h a p t e r 3 ) , s u n f l e e k s would l i k e l y c o n t r i b u t e s i g n i f i c a n t l y t o t h e t o t a l PPFD below a c a n o p y . G r o s s (1982) s t a t e d t h a t t h e c l o s e r t h e a v e r a g e low l i g h t l e v e l i s t o a p l a n t ' s c o m p e n s a t i o n p o i n t , t h e more i m p o r t a n t s u n f l e c k s become. The s t e e p s l o p e s ( c o e f f i c i e n t a) of t h e e q u a t i o n s p r e d i c t i n g s a l a l f r o m d i r e c t r a d i a t i o n s u p p o r t G r o s s ' (1982) s t a t e m e n t . My r e s u l t s s u g g e s t t h a t s a l a l d e n s i t y , b i o m a s s and s h o o t s i z e a r e l i k e l y r e g u l a t e d by an i n t e r a c t i o n o f d i r e c t r a d i a t i o n , and p r o b a b l y w i t h p l a n t age and m o i s t u r e s t a t u s , and e f f e c t s of s i t e age ( s u c c e s s i o n a l s t a g e ) and w a t e r b a l a n c e . 1 1 2 CONCLUSION S a l a l d e n s i t y , p r o d u c t i v i t y , b i o m a s s , c o v e r , and s h o o t s i z e were w e l l r e l a t e d t o t r a n s m i s s i o n of s o l a r r a d i a t i o n t h r o u g h f o r e s t c a n o p i e s . R e l a t i o n s h i p s between s a l a l a b u ndance and t r a n s m i s s i o n o f g l o b a l , d i r e c t , and d i f f u s e p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n were a s y m p t o t i c . D i f f e r e n c e s between e q u a t i o n s d e v e l o p e d i n d i f f e r e n t s u b z o n e s were a f u n c t i o n o f s t a n d s t r u c t u r e e f f e c t s on t r a n s m i s s i o n of r a d i a t i o n and s i t e e f f e c t s . S a l a l d e n s i t y , p r o d u c t i v i t y , b i o m a s s , and c o v e r were most r e s p o n s i v e t o t r a n s m i s s i o n of d i r e c t s h o r t w a v e s o l a r r a d i a t i o n . 113 REFERENCES A n d e r s o n , R.C., O.L. L o u c k s , and A.M. Swa i n . 1969. H e r b a c e o u s r e s p o n s e t o canopy c o v e r , l i g h t i n t e n s i t y , and t h r o u g h f a l l p r e c i p i t a t i o n i n c o n i f e r o u s f o r e s t s . E c o l o g y . 50:255-263. A t z e t , T. and R.H. W a r i n g . 1970. S e l e c t i v e f i l t e r i n g o f l i g h t by c o n i f e r o u s f o r e s t s and minimum l i g h t e n e r g y r e q u i r e m e n t s f o r r e g e n e r a t i o n . Can. J . B o t . 48:2163-2167. B l a c k , T.A., C S . Tan, and J.U. Nnyamah. 1980. T r a n s p i r a t i o n i n t h i n n e d and u n t h i n n e d s t a n d s . Can. J . S o i l S c i . 60:625-631. Boardman, N.K. 1977. C o m p a r a t i v e p h o t o s y n t h e s i s o f sun and shade p l a n t s . Ann. Rev. P l a n t P h y s i o l . 28:355-377. B u n n e l l , F . L . and J.M. K o c h - B a k k e r . 1 986. S a l a l {Gaul t heri a shall on) under f o r e s t c a n o p y I . P l a n t g r o w t h f o r m , (in pr ep. ) . C z a r n o w s k i , M. and J . Slomka. 1959. Some rem a r k s on t h e p e r c o l a t i o n o f l i g h t t h r o u g h t h e f o r e s t c a n o p y . E c o l o g y . 40:312-315. E v a n s , G . C 1956. An a r e a s u r v e y method o f i n v e s t i g a t i n g t h e d i s t r i b u t i o n o f l i g h t i n t e n s i t y i n woo d l a n d s , w i t h p a r t i c u l a r r e f e r e n c e t o s u n f l e c k s . J . E c o l . 44:391-428. E v a n s , L . T. 1973. The e f f e c t o f l i g h t on p l a n t g r o w t h , d e v e l o p m e n t and y i e l d , pp. 21-35 in: P l a n t R e s p o n s e t o C l i m a t i c F a c t o r s . P r o c . U p p s a l a Symp., 1970. U n e s c o , P a r i s . E z e k i e l , M. and K.A. F o x . 1970. Methods o f c o r r e l a t i o n and r e g r e s s i o n a n a l y s i s . 3 r d e d . J o h n W i l e y and Sons, I n c . New Yor k , NY. F e d e r e r , C A . and C.B. T a n n e r . 1966. S p e c t r a l d i s t r i b u t i o n o f l i g h t i n t h e f o r e s t . E c o l o g y . 47:555-560. G h o l z , H.L. 1982. E n v i r o n m e n t a l l i m i t s on a b o v e g r o u n d n e t p r i m a r y p r o d u c t i o n , l e a f a r e a , and bi o m a s s i n v e g e t a t i o n z o n e s of t h e P a c i f i c N o r t h w e s t . E c o l o g y . 63:469-481. G r i e r , C.C. and S.W. R u n n i n g . 1977. L e a f a r e a of matur e n o r t h w e s t e r n c o n i f e r o u s f o r e s t s : r e l a t i o n t o s i t e w a t e r b a l a n c e . E c o l o g y . 58:893-899. G r o s s , L . J . 1982. P h o t o s y n t h e t i c d y n a m i c s i n v a r y i n g l i g h t e n v i r o n m e n t s : a model and i t s a p p l i c a t i o n t o whole l e a f c a r b o n g a i n . E c o l o g y . 63:84-93. 1 14 G r o s s , L . J . and B.F. C h a b o t . 1979. Time c o u r s e o f p h o t o s y n t h e t i c r e s p o n s e t o c h a n g e s i n i n c i d e n t l i g h t e n e r g y . P l a n t P h y s i o l . 63:1033-1038. Hodges, J.D. 1967. P a t t e r n s o f p h o t o s y n t h e s i s under n a t u r a l e n v i r o n m e n t a l c o n d i t i o n s . E c o l o g y . 48:234-242. H o r o w i t z , J . L . 1969. An e a s i l y c o n s t r u c t e d shadow-band f o r s e p a r a t i n g d i r e c t and d i f f u s e s o l a r r a d i a t i o n . S o l a r E n e r g y . 12:543-545. K e l l i h e r , F.M. 1985. S a l a l u n d e r s t o r y r e m o v a l e f f e c t s on t h e s o i l w a t e r r e g i m e and t r e e t r a n s p i r a t i o n r a t e s i n a D o u g l a s - f i r f o r e s t . Ph.D. t h e s i s . 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 , B.C. K e y e s , M.R. and C C . G r i e r . 1981. Above- and b e l o w - g r o u n d n e t p r o d u c t i o n i n 4 0 - y e a r o l d D o u g l a s - f i r s t a n d s on low and h i g h p r o d u c t i v i t y s i t e s . Can. J . F o r . Res. 11:599-605. K l i n k a , K., R.N. G r e e n , P . J . C o u r t i n , and F . C N u s z d o r f e r . 1984. S i t e d i a g n o s i s , t r e e s p e c i e s s e l e c t i o n and s l a s h b u r n i n g g u i d e l i n e s f o r t h e V a n c o u v e r F o r e s t R e g i o n , B r i t i s h C o l u m b i a . Land Manage. R e p t . No. 25. B.C. M i n i s t r y o f F o r e s t s . V i c t o r i a , B.C. K r a j i n a , V . J . 1965. B i o g e o c l i m a t i c z o n e s and b i o g e o c o e n o s e s o f B r i t i s h C o l u m b i a . E c o l o g y o f W e s t e r n N o r t h A m e r i c a . 1:1-17. L o g a n , K.T. 1959. Some e f f e c t s o f l i g h t on g r o w t h o f w h i t e p i n e s e e d l i n g s . Can. D e p t . N o r t h e r n A f f a i r s and N a t i o n a l R e s o u r . , F o r . B r . , F o r . R e s . D i v . T e c h . Note No. 82. L o n g , J.N. and J . T u r n e r . 1975. A b o v e g r o u n d b i o m a s s o f u n d e r s t o r e y and o v e r s t o r e y i n an age s e q u e n c e o f f o u r D o u g l a s - f i r s t a n d s . J . A p p l . E c o l . 12:179-188. M i l l e r , D.H. 1959. T r a n s m i s s i o n of i n s o l a t i o n t h r o u g h p i n e f o r e s t c a n o p y , as i t a f f e c t s t h e m e l t i n g o f snow. M i t t . S c h w e i z . A n s t . f o r s t l . V e r s u c h s w e s e n . 35:57-79. Moore, C. 1984. UBC CURVE. Computing C e n t r e . U n i v e r s i t y of B r i t i s h C o l u m b i a , V a n c o u v e r , B.C. M u l l e r , R.A. 1971. T r a n s m i s s i o n components o f s o l a r r a d i a t i o n i n p i n e s t a n d s i n r e l a t i o n t o c l i m a t i c and s t a n d v a r i a b l e s . U.S.D.A. F o r . S e r v . , P a c . S o u t h w e s t F o r . and Range Exp. S t a . Res. P a p e r PSW-71. O r l o c i , L. 1965. The C o a s t a l W e s t e r n Hemlock Zone on t h e 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 m a i n l a n d . E c o l o g y o f W e s t e r n N o r t h A m e r i c a . 1:18-34. 1 1 5 R o b i n s o n , M.W. 1947. An i n s t r u m e n t t o measure f o r e s t crown c o v e r . F o r . C h r o n . 23:222-225. S a b h a s r i , S. 1961. An e c o l o g i c a l s t u d y of s a l a l (Gaultheria shall on P u r s h ) . Ph.D. t h e s i s . U n i v . o f W a s h i n g t o n , S e a t t l e , WA. S h i r l e y , H.L. 1945. L i g h t a s an e c o l o g i c a l f a c t o r and i t s measurement. I I . B o t . Rev. 11:497-532. S t a n e k , W. , D. Beddows, and D. S t a t e . 1979. F e r t i l i z a t i o n and t h i n n i n g e f f e c t s on a D o u g l a s - f i r e c o s y s t e m a t Shawnigan Lake on V a n c o u v e r I s l a n d . Can. F o r . S e r v . R e p t . No. BC-R-1. V i c t o r i a , B.C. Swank, W.T. 1972. Water b a l a n c e , i n t e r c e p t i o n , and t r a n s p i r a t i o n s t u d i e s on a w a t e r s h e d i n t h e Puget l o w l a n d r e g i o n o f w e s t e r n W a s h i n g t o n . Ph.D. t h e s i s . U n i v . o f W a s h i n g t o n , S e a t t l e , WA. Tan, C.S., T.A. B l a c k , and J.U. Nnyamah. 1977. C h a r a c t e r i s t i c s o f s t o m a t a l d i f f u s i o n r e s i s t a n c e i n a D o u g l a s - f i r f o r e s t e x p o s e d t o s o i l w a ter d e f i c i t s . Can. J . F o r . R es. 7:595-604. T h o r n l e y , J.H.M. 1976. M a t h e m a t i c a l models i n p l a n t p h y s i o l o g y . A c ademic P r e s s . New Y o r k , NY. U s t i n , S.L., R.A. Woodward, M.G. B a r b o u r , and J . L . H a t f i e l d . 1984. R e l a t i o n s h i p s between s u n f l e c k d y n a m i c s and r e d f i r s e e d l i n g d i s t r i b u t i o n . E c o l o g y . 65:1420-1428. V a l e s , D . J . a nd F. L . B u n n e l l . 1986. S a l a l (Gaultheria shallon) under f o r e s t c a n o p y I I . P a t t e r n a n a l y s i s o f d i s t r i b u t i o n . J . E c o l . (in pr e p. ) . V a l e s , D.J., F . L . B u n n e l l , A. McLeod, and R.M. E l l i s , (in prep.). B i o m a s s a l l o m e t r i c r e l a t i o n s h i p s o f s a l a l (Gaultheria shallon). Weetman, G.F., A. G e r m a i n , and R. F o u r n i e r . 1986. F e r t i l i z e r • s c r e e n i n g t r i a l s o f s t a g n a t e d S i t k a s p r u c e p l a n t a t i o n s on n o r t h e r n V a n c o u v e r I s l a n d , B.C. S o i l S c i . S o c . Am. J . ( s u b m i t t e d ) . W h i t e h e a d , F.H. 1973. The r e l a t i o n s h i p between l i g h t i n t e n s i t y and r e p r o d u c t i v e c a p a c i t y , p p. 73-75 in: P l a n t R e s p o n s e t o C l i m a t i c F a c t o r s . P r o c . U p p s a l a Symp., 1970. U n e s c o , P a r i s . Young, D.R. and W.K. S m i t h . 1979. I n f l u e n c e o f s u n f l e c k s on th e t e m p e r a t u r e and wat e r r e l a t i o n s o f two s u b a l p i n e u n d e r s t o r y c o n g e n e r s . O e c o l o g i a . 43:192-205. Z a v i t k o v s k i , J . 1976. Ground v e g e t a t i o n , b i o m a s s , p r o d u c t i o n , a n d e f f i c i e n c y o f e n e r g y u t i l i z a t i o n i n some n o r t h e r n W i s c o n s i n f o r e s t e c o s y s t e m s . E c o l o g y . 57:694-706. 1 1 7 CHAPTER 5. MANAGEMENT IMPLICATIONS INTRODUCTION The r e s u l t s o f t h i s t h e s i s c a n s e r v e two u s e f u l p u r p o s e s f o r managers. F o r e s t managers c o n c e r n e d w i t h c o m p e t i t i o n by s a l a l f o r m o i s t u r e o r n u t r i e n t s can i d e n t i f y a l e v e l of MCC o r s t o c k i n g t h a t i s h i g h enough t o s u p p r e s s s a l a l . W i l d l i f e managers i n t e r e s t e d i n p r o d u c i n g s a l a l as w i n t e r f o r a g e c a n s u g g e s t l e v e l s of f o r e s t s t o c k i n g t h a t a r e optimum f o r s a l a l h e i g h t and p r o d u c t i v i t y . S a l a l abundance c a n be p r e d i c t e d f r o m f o r e s t i n v e n t o r i e s ( e . g . , t i m b e r c r u i s e d a t a ) on s i t e s s i m i l a r t o t h o s e sampled i n t h i s s t u d y . E q u a t i o n s p r e d i c t i n g t r a n s m i s s i o n o f s o l a r r a d i a t i o n may a i d i n m o d e l i n g t h e d e e r t h e r m a l e n v i r o n m e n t under f o r e s t c a n o p i e s ( B u n n e l l e t a l . 1986), b u t b e c a u s e o f s p a t i a l h e t e r o g e n e i t y and s e a s o n a l v a r i a t i o n o f t h e r a d i a t i o n r e g i m e , t h e e q u a t i o n s i n C h a p t e r 3 must be u s e d w i t h c a u t i o n . The r e s u l t s of t h e p r e v i o u s t h r e e c h a p t e r s w i l l be i n t e g r a t e d a l o n g w i t h a d d i t i o n a l m a t e r i a l f r o m p u b l i s h e d l i t e r a t u r e t o i l l u s t r a t e how r e s u l t s f r o m p r e v i o u s c h a p t e r s c a n be a p p l i e d . 1 18 FOREST MANAGEMENT IMPLICATIONS Tan e t a l . ( 1 9 7 7 ) , B l a c k e t a l . ( 1 9 8 0 ) , K e l l i h e r ( 1 9 8 5 ) , and P r i c e e t a l . (1986) have shown t h a t s a l a l i s a s e r i o u s c o m p e t i t o r w i t h D o u g l a s - f i r t r e e s f o r s o i l m o i s t u r e on d r y s i t e s , a nd c a n r e d u c e p o t e n t i a l t r e e g r o w t h . Weetman e t a l . (1986) have s u g g e s t e d t h a t s a l a l may be a s e r i o u s c o m p e t i t o r f o r n i t r o g e n a nd p h o s p h o r u s c o n t r i b u t i n g t o "growth c h e c k " i n S i t k a s p r u c e (Picea sitchensis (Bong.) C a r r . ) p l a n t a t i o n s on n o r t h e r n V a n c o u v e r I s l a n d o l i g o t r o p h i c p e a t s i t e s . A t t a i n i n g r a p i d crown c l o s u r e and m a i n t a i n i n g h i g h s t a n d d e n s i t i e s a r e s u g g e s t e d t e c h n i q u e s t o e f f e c t i v e l y " c o n t r o l " s a l a l . B l a c k and S p i t t l e h o u s e (1981) recommended s t a n d d e n s i t i e s g r e a t e r t h a n 1500 t r e e s « h a " 1 , d e p e n d i n g on a v e r a g e s o i l w a ter p o t e n t i a l , t o m a i n t a i n h i g h crown c l o s u r e and s u p p r e s s s a l a l . T h e i r e s t i m a t e was b a s e d on a 2 5 - y e a r o l d D o u g l a s - f i r s t a n d . B e c a u s e s t a n d s a r e d y n a m i c , t h e number o f t r e e s n e e d ed depends on age and s i z e o f t h e t r e e s . R e i n e k e ' s (1933) s t a n d d e n s i t y i n d e x (SDI) c a n be u s e d t o g u i d e s t o c k i n g l e v e l s f o r s a l a l s u p p r e s s i o n . SDI i s n o t dep e n d e n t on s i t e q u a l i t y o r age. S t a n d d e n s i t y management d i a g r a m s (Drew and F l e w e l l i n g 1979) c a n g u i d e p l a n t i n g and t h i n n i n g d e n s i t i e s t h r o u g h o u t a r o t a t i o n . An SDI t h a t e f f e c t i v e l y c o n t r o l s s a l a l c a n be m a i n t a i n e d . I f p l o t s f r o m t h i s s t u d y a r e l o c a t e d on t h e s t a n d d e n s i t y d i a g r a m o f Drew and F l e w e l l i n g ( 1 9 7 9 : 5 2 3 ) , a l l p l o t s e x c e p t 3, 7, 21, and 22 119 f a l l above t h e crown c l o s u r e l i n e . P l o t s 9, and 13-15 a r e above t h e i r " l o w e r l i m i t o f t h e zone o f imminent c o m p e t i t i o n - m o r t a l i t y " . P l o t s n e a r o r above t h e c o m p e t i t i o n l i n e have s a l a l d e n s i t i e s l e s s t h a n 15 s h o o t s « m ~ 2 . An optimum management r e g i m e t o c o n t r o l s a l a l on d r y D o u g l a s - f i r s i t e s m i g h t be t o m a i n t a i n s t a n d s n e a r o r above t h e l o w e r l i m i t o f t h e zone o f imminent c o m p e t i t i o n - m o r t a l i t y . S t a n d d e n s i t i e s a t t h i s z o n e , however, would be e x p e r i e n c i n g i n t e r - t r e e c o m p e t i t i o n and t h u s n e g a t i v e l y a f f e c t p o t e n t i a l t r e e g r o w t h . The l o w e r zone r o u g h l y c o r r e s p o n d s t o an SDI of 1200. M a i n t a i n i n g an SDI of 1200 would r e q u i r e h i g h e r p l a n t i n g and r e s i d u a l t h i n n i n g d e n s i t i e s t h a n t h o s e n o r m a l l y u s e d ( d e n s i t i e s g i v e n i n N y b e r g 1985). The number of t r e e s r e q u i r e d t o m a i n t a i n t h e 1200 SDI c o u l d be c a l c u l a t e d a t any p o i n t i n t i m e by: t t r e e s - h a " 1 = 1200/(DBH / 2 5 ) 1 • 6 (Long 1985). The number of t r e e s needed t o m a i n t a i n SDI's o f 600, 800, 1000, and 1200 a t d i f f e r e n t d i a m e t e r s a r e p r e s e n t e d i n T a b l e 5.1. As seen i n T a b l e 5.1, t h e e x t r a o r d i n a r i l y h i g h t r e e d e n s i t i e s a r e n o t p r a c t i c a l f o r o p e r a t i o n a l f o r e s t management r e g i m e s u s i n g D o u g l a s - f i r . The s a l a l d e n s i t y a t w h i c h l i t t l e o r no c o m p e t i t i o n o c c u r s w i t h f o r e s t t r e e s i s n o t known. B l a c k and S p i t t l e h o u s e (1981) m o d e l e d t h e w ater b a l a n c e t o s u g g e s t s t a n d d e n s i t i e s needed t o s u p p r e s s s a l a l . Tan e t a l . (1977) r e p o r t e d t h a t s a l a l s t o m a t a l c l o s u r e began a t a p h o t o n f l u x d e n s i t y o f 250-350 M E « n r 2 ' S " 1 . O s b e r g (1986) s u g g e s t e d t h a t s t a n d s be d e n s e enough t o keep b e l o w - c a n o p y e n e r g y f l u x d e n s i t i e s under TABLE 5.1 T r e e d e n s i t i e s n e e d e d t o m a i n t a i n a c o n s t a n t s t a n d d e n s i t y i n d e x a s a v e r a g e d i a m e t e r c h a n g e s D B H ° q # T r e e s / h a f o r SDI b • • (cm) 600 800 1000 1200 2 34135 4551 4 56892 68271 4 1 1 261 1 501 4 18768 22521 6 5886 7848 9810 1 1772 8 371 5 4953 6191 7429 10 2599 3466 4332 5199 1 2 1 942 2589 3236 3883 1 4 1517 2023 2529 3034 1 6 1 225 1 634 2042 2451 18 1015 1353 1691 2030 20 857 1 1 43 1 429 1715 22 736 982 1 227 1 472 24 640 854 1067 1 281 26 564 751 939 1 1 27 28 500 667 834 1001 30 448 598 747 896 32 404 539 674 808 34 367 489 61 1 734 36 335 446 558 670 38 307 409 512 614 40 283 377 471 566 42 262 349 436 523 44 243 324 405 486 46 226 302 377 452 48 21 1 282 352 423 50 198 264 330 396 flDiameter o f t r e e of a v e r a g e b a s a l a r e a . R e i n e k e ' s s t a n d d e n s i t y i n d e x . 121 20 W « m ~ 2 , t h u s e f f e c t i v e l y r e d u c i n g u n d e r s t o r y e v a p o t r a n s p i r a t i o n r a t e . On c l e a r , sunny summer d a y s t h e s o l a r i r r a d i a n c e above a c a n o p y c a n r a n g e 800-1000 W « m " 2 . U s i n g O s b e r g ' s (1986) recommended 20 W-nr 2, and a maximum 900 W « m ~ 2 a b o v e - c a n o p y g l o b a l i r r a d i a n c e , t r a n s m i s s i o n o f g l o b a l r a d i a t i o n would be a b o u t 2%. C o e f f i c i e n t c i n C h a p t e r 4 e q u a t i o n s ( T a b l e 4.4) s u g g e s t e d t h a t a t 3% t r a n s m i s s i o n o f g l o b a l r a d i a t i o n s a l a l d e n s i t y w o u l d be z e r o . W o r k i n g back t h r o u g h t h e e q u a t i o n i n C h a p t e r 3 p r e d i c t i n g g l o b a l r a d i a t i o n f r o m SDI f o r a l l p l o t s c o m b i n e d g i v e s an e s t i m a t e d SDI of 1065 a t 2% t r a n s m i s s i o n and 984 a t 3%. S t a n d s h a v i n g an SDI g r e a t e r t h a n 1000 wou l d l i k e l y have an a d v e r s e e f f e c t on s a l a l , b u t s i t e e f f e c t s o r s i d e l i g h t i n g may s u p p o r t h i g h e r a b u n d a n c e s t h a n e x p e c t e d . Crown c l o s u r e i s c o n v e n t i o n a l l y d e f i n e d by f o r e s t e r s a s t h e t i m e when crowns b e g i n t o t o u c h and c o v e r t h e e n t i r e g r o w i n g a r e a . I t i s a u s e f u l measure o f a s t a n d t h a t i s i n d e p e n d e n t o f a g e . O v e r s t o r y c o v e r a s measured by t h e moosehorn i s a measure o f crown c o m p l e t e n e s s , o r an e s t i m a t e o f t r e e f o l i a g e d e n s i t y and i s a n a l o g o u s t o a c o v e r e s t i m a t e o f an u n d e r s t o r y s p e c i e s . When t r e e crowns a r e o v e r l a p p i n g , t h e r e i s 100% crown c l o s u r e , b u t t h i s may c o r r e s p o n d r o u g h l y t o o n l y 70% mean crown c o m p l e t e n e s s . Crown c o m p l e t e n e s s i s a u s e f u l c o n c e p t i n r e s e a r c h b e c a u s e i t i s a s u r r o g a t e f o r p r o c e s s e s a c t i n g below t h e canopy ( l i g h t t r a n s m i s s i o n o r t h r o u g h f a l l p r e c i p i t a t i o n ) . Crown c o m p l e t e n e s s as measured w i t h a moosehorn, however, may n o t be a s o p e r a t i o n a l l y p r a c t i c a l a s u s i n g a e r i a l p h o t o g r a p h s t o e s t i m a t e crown c l o s u r e . Bonnor (1968) r e l a t e d measurements made w i t h t h e moosehorn t o c o v e r e s t i m a t e s o b t a i n e d from a e r i a l p h o t o s , f o u n d t h a t e s t i m a t e s made from t h e g r o u n d were a b o u t 10% h i g h e r t h a n h i s e s t i m a t e s made from a e r i a l p h o t o g r a p h s . R e l a t i o n s h i p s between MCC and s t a n d c h a r a c t e r i s t i c s f o r a g i v e n l e v e l o f s t o c k i n g c a n be d e v e l o p e d and u s e d i f MCC i s th e d e s i r e d i n d e p e n d e n t v a r i a b l e t o use t o p r e d i c t s a l a l . 123 WILDLIFE MANAGEMENT IMPLICATIONS B e c a u s e s a l a l i s an i m p o r t a n t w i n t e r f o o d f o r b l a c k - t a i l e d d e e r (Cowan 1945; Brown 1961; R o c h e l l e 1980), managers may want t o e n c o u r a g e f o r a g e p r o d u c t i o n on d e e r w i n t e r r a n g e s by m a n i p u l a t i n g f o r e s t s t a n d s ( e . g . , N y b e r g e t a l . 1986). Medium s i t e s t a n d s on s o u t h e r n a s p e c t s were s t u d i e d t o a v o i d d e v e l o p i n g p r e s c r i p t i o n s f o r s a l a l p r o d u c t i o n on good f o r e s t s i t e s and p o t e n t i a l c o n f l i c t s w i t h f o r e s t g r o w t h o b j e c t i v e s . B e c a u s e e x t e n s i v e homogeneous c o v e r of s a l a l was not f o u n d d u r i n g p l o t s e l e c t i o n , and s a l a l p a t c h e s a r e u s u a l l y s p a t i a l l y h e t e r o g e n e o u s , s i n g l e p r e s c r i p t i o n s o v e r a l a r g e a r e a t o m a i n t a i n a l e v e l o f MCC may no t y i e l d r e s u l t s p r e d i c t e d f r o m t h e r e g r e s s i o n s p r e s e n t e d h e r e . E x p l o i t i n g n a t u r a l o p e n i n g s a nd f o r a g e p a t c h e s (Nyberg e t a l . 1986) i n s m a l l a r e a s may p r o v i d e p r e d i c t a b l e r e s p o n s e s i n s m a l l p a t c h e s . B e c a u s e b i o m a s s r e l a t i o n s h i p s a r e g e n e r a l l y h y p e r b o l i c , a s m a l l change i n MCC w i l l r e s u l t i n a p r o p o r t i o n a t e l y l a r g e r change i n f o r a g e p r o d u c t i o n o r b i o m a s s . Management o f s a l a l a s a s i n g l e w i n t e r f o r a g e s p e c i e s may be unwise b e c a u s e a mixed d i e t seems t o a i d d i g e s t i o n ( e . g . , R o c h e l l e 1980). A r b o r e a l l i c h e n {Alectoria sarmentosa) may i n c r e a s e t h e d i g e s t i b i l i t y o f s a l a l ( R o c h e l l e 1980). Brown (1961) r e p o r t e d f e e d i n g t r i a l s l a s t i n g 30, 40, 41, and 71 d a y s -d u r i n g w h i c h d e e r were f e d o n l y s a l a l r e s u l t i n g i n l o s s e s o f 8.0, 17.5, 9.5, and 22.2% o f body mass, r e s p e c t i v e l y . B l a c k - t a i l e d d e e r , however, may l o s e up t o 25% o f t h e i r body mass d u r i n g w i n t e r (Bandy 1965; R o c h e l l e 1980). An u n d e r s t o r y o f o n l y s a l a l may t h e r e f o r e s u s t a i n d e e r f o r s h o r t , c r i t i c a l p e r i o d s of heavy s n o w f a l l , p r o v i d e d t h a t t h e s a l a l i s n o t b u r i e d o r t o o dense t o r e s t r i c t movement. G a t e s (1968) s u g g e s t e d t h a t a l t h o u g h s a l a l a s s o c i a t i o n s may have h i g h p r o d u c t i v i t y , u t i l i z a t i o n may be low b e c a u s e o f t h e low d i v e r s i t y o f f o r a g e s p e c i e s . E s t i m a t e s o f s a l a l c r u d e p r o t e i n a r e v a r i e d but a r e g e n e r a l l y l e s s t h a n t h e 7% r e q u i r e d f o r w i n t e r m a i n t e n a n c e ( D i e t z 1965). S a l a l f o l i a r c r u d e p r o t e i n ( c o n v e r t e d f r o m % n i t r o g e n « 6 . 2 5 where n e c e s s a r y ) was r e p o r t e d by D e a l y (1959) as 4.4-6.3%, S a b h a s r i (1961) a s 5% d r y mass, Brown (1961) 5-8%, H e i l m a n (1961) 5-7.5%, G a t e s (1968) 3.7-9.7%, Webber (1969) 2.3-3.8%, D i c e (1970) 4.0%, K l i n k a (1976) 5%, a rang e of 5-10.8 w i t h an a v e r a g e o f 6.5% by R o c h e l l e ( 1 9 8 0 ) , and 4.4-8.6% by McCann ( 1 9 8 5 ) . S t a n e k e t a l . (1979) showed t h a t n i t r o g e n i n s a l a l c o u l d be a f f e c t e d by t h i n n i n g a n d / o r f e r t i l i z a t i o n . R o c h e l l e (1980) f o u n d in vitro d i g e s t i b i l i t y o f s a l a l f o l i a g e i n w i n t e r a t 26-33%, v o l a t i l e f a t t y a c i d c a l o r i c v a l u e of 2.0 k c a l * g ~ 1 , and r a t e o f d i g e s t i o n was 88% o v e r 24 h o u r s , and 100% o v e r 36 h o u r s . S e i p (1979) r e p o r t e d t h a t i n O c t o b e r , g r o s s e n e r g y of c u r r e n t a n n u a l g r o w t h f o l i a g e was 4.8 k c a l * g ~ 1 w i t h in vitro d i g e s t i b i l i t y o f 32.6% y i e l d i n g 1.6 k c a l « g ~ 1 d i g e s t i b l e e n e r g y . U s i n g an a v e r a g e l i v e b i o m a s s (W) o f 46 kg (Hovey 1984) f o r a V a n c o u v e r I s l a n d b l a c k - t a i l e d d e e r and d r y mass d a i l y 125 f o r a g e i n t a k e o f 50 g « W 0 - 7 5 ( H a n l e y 1984), an a v e r a g e d e e r c o u l d e a t a b o u t 900 g o f f o r a g e p e r day i n w i n t e r . I f a c o n s e r v a t i v e ( h i g h ) a c t i v i t y i n c r e m e n t o f 2 ( H a n l e y 1984) i s u s e d , an a v e r a g e d e e r would r e q u i r e 2 » 7 0 W ° - 7 5 o r 2473 k c a l ' d a y " 1 o f e n e r g y . A d e e r e a t i n g o n l y s a l a l may a c q u i r e a b o u t 1346 k c a l « d a y " 1 o f m e t a b o l i z a b l e e n e r g y (900 g • 2.0 k c a l « g _ 1 • 0.85 m e t a b o l i z a b l e e n e r g y c o e f f i c i e n t • 0.88 d i g e s t e d i n 24 h o u r s ) r e s u l t i n g i n an e n e r g y d e f i c i t of a r o u n d 1127 k c a l - d a y " 1 . The e n e r g y d e f i c i t t r a n s l a t e s t o a b o u t a 188 g « d a y ~ 1 b i o m a s s l o s s ( a s s u m i n g 6 k c a l « g ~ 1 f a t o f m e t a b o l i z a b l e e n e r g y ; Mautz 1978). As b i o m a s s l o s s o c c u r r e d , e n e r g y r e q u i r e m e n t s w o u l d d e c l i n e , b ut i n t a k e r a t e may a l s o d e c l i n e . On a s a l a l - o n l y d i e t i t would t a k e 61 days f o r t h e a v e r a g e d e e r t o r e a c h a 25% b i o m a s s l o s s . S a l a l , however, may be o n l y 20-50% by volume o f t h e w i n t e r d i e t o f b l a c k - t a i l e d d e e r (Brown 1961; G a t e s 1968; J o n e s 1975; R o c h e l l e 1980). M i x e d d i e t s a r e h i g h e r i n d i g e s t i b l e e n e r g y ( R o c h e l l e 1980). An optimum t r a d e o f f between snow i n t e r c e p t i o n and f o r a g e p r o d u c t i o n i s d e s i r e d . D u r i n g w i n t e r , snow b u r i e s f o r a g e r e d u c i n g a v a i l a b i l i t y . T a l l , e r e c t s h r u b s a r e l e s s r e a d i l y b u r i e d . B e c a u s e b u r i a l r a t e s a r e n o t b e l i e v e d t o be a l i n e a r f u n c t i o n o f snow d e p t h , s h o o t s t a l l e r t h a n t h e d e p t h of snow ca n be b u r i e d ( e . g . , H a r e s t a d 1979). T a l l e s t s a l a l s h o o t s a r e i n t h e 65-80% MCC range ( F i g . 2.7) and t h e g r e a t e s t p e r c e n t a g e o f t a l l s h o o t s a r e a l s o i n t h i s r a n g e ( A p p e n d i x 1 4 ) . S h o o t s under h i g h e r c a n o p i e s , t h o u g h , may have weaker stems ( A p p e n d i x 13) and may be more r e a d i l y b u r i e d by snow p a s s i n g t h r o u g h t h e 1 26 c a n o p y . S a l a l may be managed by u s i n g t h e SDI c o n c e p t p r e s e n t e d i n t h e p r e v i o u s s e c t i o n . Lower SDI's t h a n what wo u l d be r e q u i r e d f o r s a l a l c o n t r o l would be n e c e s s a r y . B e c a u s e MCC p r e d i c t e d b i o m a s s w e l l , i n d i c a t e d no d i f f e r e n c e among e q u a t i o n s d e v e l o p e d i n i n d i v i d u a l v a r i a n t s , and has been a c o n c e p t u s e d f o r snow i n t e r c e p t i o n ( B u n n e l l e t a l . 1985; McNay 1985) and f o r a g e a bundance, MCC w i l l be u s e d i n t h e examples t h a t f o l l o w . From t h e r e g r e s s i o n s i n C h a p t e r 2, an e s t i m a t e d 75 k g - h a " 1 o f CAGBIOM and 287 k g - h a " 1 o f FOLBIOM c o u l d be f o u n d under 80% MCC and 181 k g - h a " 1 CAGBIOM and 537 k g - h a " 1 FOLBIOM under 65% MCC. B e c a u s e t h e abundance o f a r b o r e a l l i c h e n s i s low i n young s t a n d s ( B u n n e l l and J o n e s 1984), s a l a l c o u l d become a more i m p o r t a n t component of w i n t e r d i e t s . A s s u m i n g t h a t s a l a l was 70% o f t h e d r y m a t t e r f o r a g e i n t a k e i n immature s t a n d s (560 g » d a y ~ 1 ) , s a l a l was 100% a v a i l a b l e , and d e e r c o u l d f i n d a l l s a l a l , CAGBIOM c o u l d s u p p o r t 2.23 d e e r « h a " 1 o v e r a 60 day p e r i o d i n an 80% MCC s t a n d and 5.39 d e e r « h a _ 1 i n a 65% MCC s t a n d . Under a 65% MCC c a n o p y s h o o t s may be s h o r t e r and more l i k e l y b u r i e d b e c a u s e o f r e d u c e d snow i n t e r c e p t i o n and t h u s r e d u c e d f o r a g e a v a i l a b i l i t y . S h o o t s under d e n s e r c a n o p i e s , however, m i g h t have weaker stems w h i c h would be d i s p l a c e d and b u r i e d more r e a d i l y t h a n s h o o t s h a v i n g s t o u t stems under more open c a n o p i e s . H a r e s t a d (1979) b e l i e v e d t h a t 75% o f f o r a g e p r o v i d e d by s h r u b s would be b u r i e d by snow d e p t h s between 50-110 cm. H i s e s t i m a t e d i d n o t a c c o u n t f o r d i s p l a c e m e n t o f stems and was b a s e d upon t a l l , e r e c t Vaccinium s p p . s h o o t s . I f snow r e d u c e d s a l a l a bundance t o o n l y 1% a v a i l a b i l i t y (assume i n c r e a s e d snow i n t e r c e p t i o n by h i g h e r c a n o p i e s was o f f s e t by weaker stems b e i n g more r e a d i l y b u r i e d ) , and d e e r s t i l l c o u l d f i n d a l l s a l a l , o n l y 0.02 and 0.05 d e e r « h a ~ 1 c o u l d be s u p p o r t e d by CAGBIOM o v e r a 60 day p e r i o d i n s t a n d s o f 80% and 65% MCC, r e s p e c t i v e l y . Under s e v e r e c o n d i t i o n s , FOLBIOM would a l s o be consumed, p o t e n t i a l l y s u p p o r t i n g 0.11 and 0.21 d e e r « h a - 1 under 80% and 65% MCC c a n o p i e s , r e s p e c t i v e l y . The s e v e r e w i n t e r o f 1971-72 had ^60 d a y s w i t h > 75 cm snowpack ( J o n e s 1975). A l t h o u g h t h e p r e c e d i n g example i s b a s e d on many a s s u m p t i o n s , i t i n d i c a t e s t h a t t w i c e as many d e e r c o u l d be s u p p o r t e d u n d e r a 65% c a n o p y t h a n an 80% c a n o p y . C o n t i n u e d p r e s s u r e on t h e f o r a g e r e s o u r c e may r e d u c e abundance and q u a l i t y i n s u b s e q u e n t y e a r s . M o d e l i n g e f f o r t s l i k e t h e p r e c e d i n g example s h o u l d t a k e i n t o a c c o u n t s h o o t h e i g h t and s h o o t p o s t u r e . B e c a u s e i n f o r m a t i o n on s h r u b b u r i a l f u n c t i o n s i s l a c k i n g and J a y (1985) i d e n t i f i e d s h r u b b u r i a l by snow as a c r i t i c a l l i n k , I s u g g e s t t h a t f u r t h e r work be done on d e v e l o p i n g s h r u b b u r i a l f u n c t i o n s . S h r u b b u r i a l work s h o u l d i n c l u d e t e s t s o f t h e b u r i a l f u n c t i o n s among s h o o t s o f d i f f e r e n t g r o w t h forms and among d i f f e r e n t l e v e l s o f MCC. S a l a l h e i g h t p e a k s under m o d e r a t e l y c l o s e d c a n o p i e s but t h e l e v e l o f MCC where t h e peak o c c u r s may be a f f e c t e d by s t a n d s t r u c t u r e ( e . g . , s i d e l i g h t i n g ) o r a g e . A d d i t i o n a l work s h o u l d be done t o examine t h e 128 c o n s i s t e n c y o f l o c a t i o n o f t h e peak. A t t e n t i o n must be g i v e n t o t h e o v e r s t o r y sample d e s i g n b e c a u s e peak l o c a t i o n s may be s e n s i t i v e t o MCC measurements ( e . g . , s i z e o f p l o t , c o m p l e t e c o v e r a g e , t e c h n i q u e u s e d ) . B e c a u s e s a l a l s h o o t s may become weaker a t i n c r e a s i n g MCC ( A p p e n d i x 13; l a c k o f o t h e r s h o o t s f o r s u p p o r t o r t o o r a p i d e l o n g a t i o n f o r amount o f r a d i a l stem g r o w t h ) , f u r t h e r work s h o u l d be done t o v e r i f y t h e r e l a t i o n s h i p o f s h o o t p o s t u r e t o MCC. 129 R E F E R E N C E S Bandy, P . J . 1965. A s t u d y of c o m p a r a t i v e g r o w t h i n f o u r r a c e s o f b l a c k - t a i l e d d e e r . Ph.D. t h e s i s , 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 , B.C. B l a c k , T.A., C S . Tan, and J.U. Nnyamah. 1980. 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( s u b m i t t e d ) . 133 A P P E N D I X 1 F o r e s t s t a n d c h a r a c t e r i s t i c s o f p l o t s Definition of forest variables MCC - mean crown c o m p l e t e n e s s o f p l o t ( a v e r a g e o f 52 moosehorn s a m p l e s and r e p o r t e d a s a f r a c t i o n ) NTREES - number of p l o t t r e e s - h a " 1 £ 8.0 cm NSAPL - # p l o t s a p l i n g s « h a " 1 < 8.0 cm and > 20 cm t a l l BA - b a s a l a r e a ( m 2 « h a ~ 1 ) o f p l o t t r e e s ^ 8.0 cm SUMDIA - sum of DBH (mm/225 m 2) o f p l o t t r e e s > 8.0 cm AVGDIA - a v e r a g e DBH (mm) o f p l o t t r e e s t 8.0 cm HT - a v e r a g e t r e e h e i g h t (m) o f p l o t t r e e s ^ 8.0 cm HBLC - a v e r a g e h e i g h t t o base o f l i v e crown (m) o f p l o t t r e e s £ 8.0 cm CRNDEP - a v e r a g e crown d e p t h (HT - HBLC) o f p l o t t r e e s > 8. 0cm DF%# - p e r c e n t o f NTREES t h a t a r e D o u g l a s - f i r WH%# - p e r c e n t o f NTREES t h a t a r e w e s t e r n hemlock MISC%# - p e r c e n t o f NTREES o t h e r t h a n D o u g l a s - f i r and w e s t e r n hemlock DF%BA - p e r c e n t o f BA o c c u p i e d by D o u g l a s - f i r WH%BA - p e r c e n t o f BA o c c u p i e d by w e s t e r n hemlock MISC%BA - p e r c e n t o f BA o c c u p i e d by s p e c i e s o t h e r t h a n D o u g l a s - f i r a nd w e s t e r n hemlock AVGBADIA- DBH (mm) o f t r e e o f a v e r a g e b a s a l a r e a f o r t r e e s > 8.0 cm SDI - R e i n e k e ' s " s t a n d d e n s i t y i n d e x " ( R e i n e k e 1933; Long 1985) computed f r o m N TREES•(AVGBADIA/25) 1• 6 BAFBA - a v e r a g e s t a n d b a s a l a r e a ( m 2 ' h a _ 1 ) o f t r e e s ^ 8.0 cm d e t e r m i n e d f r o m 5 BAF„ p r i s m s a m p l e s BAFDIA - a v e r a g e DBH ( i n mm) o f t r e e s S 8.0 cm sampled by 5 BAF 4 p r i s m s a m p l e s BAFTREES- a v e r a g e number o f t r e e s « h a ~ 1 ^ 8.0 cm d e t e r m i n e d from 5 BAF„ p r i s m s a m p l e s BAFSAPL - a v e r a g e number o f s a p l i n g s « h a " 1 < 8.0 cm d e t e r m i n e d f r o m 5 BAF« p r i s m s a m p l e s BAFBADIA- DBH (mm) o f t r e e of a v e r a g e b a s a l a r e a d e t e r m i n e d from p r i s m s a m p l i n g BAFSDI - R e i n e k e ' s " s t a n d d e n s i t y i n d e x " d e t e r m i n e d from p r i s m s a m p l i n g computed from B A F T R E E S - ( B A F B A D I A / 2 5 ) 1 • 6 DOWN - a v e r a g e b a s a l a r e a of two do w n s l o p e c o r n e r p r i s m s amples UP - a v e r a g e b a s a l a r e a o f two u p s l o p e c o r n e r p r i s m s amples RIGHT - a v e r a g e b a s a l a r e a of two r i g h t c o r n e r p r i s m s amples L E F T - a v e r a g e b a s a l a r e a of two l e f t c o r n e r p r i s m s amples CENTER - b a s a l a r e a o f p r i s m sample i n p l o t c e n t e r A P P E N D I X 1 F o r e s t s t a n d c h a r a c t e r i s t i c s of p l o t s P l o t MCC NTREES NSAPL BA SUMDIA AVGDIA HT HBLC CRNDEP DF%# WH°/o# MISC%# DF%BA WH%BA MISC%BA U / h a ) ( # / h a ) ( m J/ha) (mm/225mI ) (mm) (m) (m) (m) 1 0 .912 2533 4178 37 . 7 7469 131 12 .4 3 .0 9 .4 25 75 0 28 72 0 2 0. . 782 1600 1378 46 .7 6212 173 13 .6 3 . 5 10 . 1 28 36 36 61 23 16 3 0 .554 533 400 21 .2 2559 213 13 .6 2 .0 1 1 .6 50 17 33 68 14 18 4 O, . 793 1778 1911 53 .4 7112 178 16 . 1 8 .6 7 . 5 82 18 0 86 14 0 5 0. .636 756 44 35 .0 3991 235 25 . 2 17 .9 7 . 3 100 0 0 100 0 0 6 0. . 783 1733 1022 34 .4 5660 145 15 .6 9 .8 5 .8 100 0 0 100 0 0 7 0. . 345 267 844 14 .8 1316 219 15 . 7 2 .6 13 . 1 33 67 0 8 92 0 8 0. .651 667 800 30 .7 3333 222 18 . 1 5 .0 13 . 1 13 60 27 10 47 43 9 0. .899 2711 3467 54. .9 9096 149 15 .0 7. . 1 7 .9 16 82 2 37 62 1 10 0. . 746 1200 711 32. .5 4461 165 15 .5 5. . 1 10 .4 96 4 0 99 1 0 1 1 0. 895 1244 622 61 . 0 5877 210 15. .6 6 , 3 9. . 3 0 79 21 0 62 38 12 0. ,641 844 1822 25 . 5 3401 179 12 . 8 4 , 0 8 . 8 68 16 16 91 4 5 13 0. 799 2000 1067 62. 2 8347 185 17 . 6 9. . 3 8. . 3 62 25 13 78 12 10 14 0. 843 2444 3111 67. 6 9427 171 17. ,4 9. .9 7 . 4 67 22 1 1 84 1 1 5 15 0. 792 2089 3289 62 . 0 8534 182 13. .9 5. .9 7 . 9 72 7 21 90 2 8 21 0. 576 889 2133 10. 1 2194 1 10 9. 7 0. 8 8. 9 95 5 0 97 3 0. 22 0. 416 756 400 8 . 5 2001 1 18 10. 3 0. 5 9. 8 100 0 0 100 0 0. 23 0. 809 2222 5556 41 . 6 7206 144 13 . 4 2 . 1 1 1 . 3 48 38 14 74 20 6 24 0. 636 1111 3200 26. 1 3972 159 14. 3 1 . 5 12 . 8 56 20 24 64 1 1 25 25 0. 736 1200 431 1 20. 0 3719 138 13. 6 2. 1 1 1 . 5 41 33 26 57 22 21 2G 0. 902 2622 7111 38 . 9 7576 128 12. 7 3. 4 9. 3 8 85 7 28 62 10 27 o. 757 1378 8000 17 . 5 3676 1 19 1 1 . 5 2 . 8 8. 7 61 32 7 52 30 18 APPENDIX 1 c o n t i n u e d P l o t AVGBADIA (mm) SDI BAFBA (m'/ha) BAFDIA (mm) BAFTREES (#/ha) BAFSAPL (#/ha) BAFBADIA (mm) BAFSDI DOWN (m*/ha)(m UP RIGHT !/ha)(m'/ha)(m LEFT '/ha) CENTER (m'/ha) 1 138 974 30 .4 168 2018 365 138 784 30 26 28 28 40 2 193 1055 40 .0 249 1312 1065 197 896 44 36 36 44 40 3 225 450 30 .4 256 927 0 204 671 34 34 42 26 16 4 196 1201 48 .0 230 1637 1121 193 1084 52 44 50 46 48 5 243 722 36 .8 385 462 0 318 681 36 28 28 36 56 6 159 839 31 .2 229 1 155 1087 185 716 36 32 36 32 20 7 266 295 18 .4 255 730 0 179 428 22 20 20 22 8 8 242 634 32 .8 288 638 0 256 662 32 36 30 38 28 9 161 1335 58 .4 182 3325 2661 150 1461 54 72 54 70 40 10 186 746 38 .4 268 1239 404 199 858 44 36 38 42 32 1 1 250 1243 59 .2 440 1062 731 266 1 176 48 72 66 54 56 12 196 572 28 , .8 234 909 208 201 640 30 30 36 24 24 13 199 1388 53 . 6 241 1711 0 200 1 195 52 48 50 50 68 14 188 1544 59 . 2 222 2546 1033 172 1400 48 60 54 54 80 15 194 1397 41 , .6 253 1361 648 197 932 36 32 44 34 52 21 120 275 12 . 0 141 1095 5091 118 330 14 14 16 12 4 22 120 233 8 . 8 144 741 564 123 238 12 8 4 16 4 23 154 1028 31 . 2 190 1625 5954 156 767 32 28 36 26 36 24 173 616 25 . 6 214 1027 393 178 597 24 26 28 22 28 25 146 505 24 . 0 203 1390 5012 148 603 24 22 18 28 40 26 137 1005 31 . 2 173 2250 5170 133 818 30 24 28 26 48 27 127 467 21 . 6 181 1481 2064 136 561 26 18 22 22 24 136 APPENDIX 2 Means and 95% c o n f i d e n c e i n t e r v a l s f o r u n d e r s t o r y c h a r a c t e r i s t i c s of p l o t s Definition of understory variables DENSITY - b a c k t r a n s f o r m e d a v e r a g e d e n s i t y of s h o o t s « m ~ 2 CAGBIOM - b a c k t r a n s f o r m e d a v e r a g e c u r r e n t a n n u a l g r o w t h f o l i a r b i o m a s s ( g « m ~ 2 ) p e r p l o t FOLBIOM - b a c k t r a n s f o r m e d a v e r a g e e s t i m a t e d s t a n d i n g c r o p f o l i a r b i o m a s s ( g « n r 2 ) p e r p l o t ( e x c l u d e s CAGBIOM) TOTBIOM - b a c k t r a n s f o r m e d a v e r a g e e s t i m a t e d s t a n d i n g c r o p f o l i a r and woody stem b i o m a s s ( g « m ~ 2 ) p e r p l o t ( e x c l u d e s CAGBIOM) PCTCOVER- b a c k t r a n s f o r m e d a v e r a g e q u a d r a t (0.25 m 2) p e r c e n t c o v e r of s a l a l p e r p l o t REPHT - b a c k t r a n s f o r m e d a v e r a g e r e p o s e h e i g h t (cm) p e r s h o o t p e r p l o t STRHT - b a c k t r a n s f o r m e d a v e r a g e s t r e t c h h e i g h t (cm) p e r s h o o t p e r p l o t BASDIA - b a c k t r a n s f o r m e d a v e r a g e b a s a l d i a m e t e r (cm) p e r s h o o t p e r p l o t APPENDIX 2 M e a n s a n d 9 5 % c o n f i d e n c e i n t e r v a l s f o r u n d e r s t o r y c h a r a c t e r i s t i c s o f p l o t s P l o t D E N S I T Y Q m - ' ) a C A G B I O M ( g m ' ) a F O L B I O M ( g m - ' ) 3 T O T B I O M ( g m - ' ) 3 X 0 . 9 5 C . I X 0 . 9 5 C . I . X O . 9 5 C . I . X 0 . 9 5 C . I 1 0 . 6 5 0 . 1 1 - 1 . 6 5 0 . 0 2 0 . 0 0 - 0 . 0 8 0 . 0 8 0 . 0 1 - 0 . 3 2 0 . 2 3 0 . 0 2 - 0 . 9 5 2 1 0 . 8 3 6 . 8 6 - 1 5 . 7 0 2 . 1 3 1 . 0 0 - 3 . 8 8 5 . 5 7 2 . 9 6 - 9 . 4 0 2 0 . 0 7 1 0 . 0 5 - 3 5 . 2 0 3 4 0 . 5 8 3 1 . 0 6 - 5 1 . 3 7 1 1 . 3 1 7 . 9 1 - 1 5 . 5 7 2 2 . 5 4 1 5 . 4 7 - 3 1 . 4 8 1 0 6 . 2 7 7 0 . 5 0 - 1 5 2 . 4 5 4 1 4 . 4 1 1 0 . 3 3 - 1 9 . 1 6 6 . 6 5 4 . 1 1 - 1 0 . 0 6 2 0 . 0 4 1 1 . 4 8 - 3 2 . 0 5 6 6 . 2 7 3 5 . 5 6 - 1 1 0 . 9 6 5 2 8 . 1 6 2 3 . 5 5 - 3 3 . 18 2 8 . 1 3 2 0 . 0 2 - 3 8 . 17 7 2 . 5 0 5 2 . 7 4 - 9 6 . 6 6 2 7 1 . 0 7 1 8 9 . 4 2 - 3 7 3 . 3 4 6 ' 1 6 . 4 7 1 2 . 8 1 - 2 0 . 6 0 2 5 . 5 6 1 5 . 1 5 - 3 9 . 8 8 9 3 . 8 6 5 8 . 7 5 - 1 4 0 . 7 6 4 0 0 . 2 8 2 4 2 . 9 6 - 6 1 4 . 0 3 7 6 7 . 9 9 5 7 . 1 6 - 7 9 . 7 5 6 4 . 6 5 5 0 . 4 0 - 8 1 . 3 7 1 7 2 . 6 2 1 3 0 . 8 6 - 2 2 2 . 4 3 6 3 3 . 5 7 4 6 6 . 9 2 - 8 3 5 . 8 0 8 1 3 . 8 4 8 . . 7 9 - 2 0 . 0 4 6 . 1 4 2 , . 9 5 - 1 1 . 0 5 1 4 . 4 9 7 . 2 7 - 2 5 . 3 9 4 6 . 8 1 2 2 . . 3 3 - 8 4 . 7 2 9 0 . 1 2 0 , , 0 1 - 0 . 3 8 0 . 0 0 0 , . 0 0 - 0 . 0 1 0 . 0 1 0 . 0 0 - 0 . 0 7 0 . 0 6 0 , . 0 0 - 0 , . 3 1 1 0 1 5 . 6 5 1 2 , , 3 7 - 1 9 . 3 1 1 3 . 5 0 8 . 7 3 - 1 9 . 7 4 2 9 . 4 4 1 7 . 4 9 - 4 5 . 8 7 1 3 3 , . 7 9 8 0 . , 8 8 - 2 0 5 , . 8 3 1 1 1 . 0 3 0 . , 3 4 - 2 . 0 9 0 . 0 1 0 . 0 0 - 0 . 0 3 0 . 2 0 0 . 0 4 - 0 . 5 7 0 . . 6 3 0 . 1 1 - 1 , . 8 6 1 2 2 0 . 8 9 1 6 . 7 6 - 2 5 . 4 8 2 6 . 0 9 17 . 6 8 - 3 6 . 8 1 5 3 . 6 2 3 0 . 8 3 - 8 5 . 5 4 2 4 0 , . 8 4 1 2 1 . 1 5 - 4 2 1 , , 0 7 1 3 1 4 . 5 0 1 1 . 1 3 - 1 8 , . 3 1 5 . 5 8 3 . 4 2 - 8 . 4 8 1 6 , . 0 7 7 . 9 9 - 2 8 . 3 1 7 3 . . 3 3 3 7 . 5 9 - 1 2 6 . , 6 1 1 4 1 . . 5 7 0 . 6 3 - 2 , . 9 3 0 . 18 0 . 0 5 - 0 . 4 4 0 . . 2 9 0 . 0 5 - 0 . 8 9 1 . . 3 9 0 . 2 4 - 4 . , 2 1 1 5 1 2 . . 1 2 9 . 1 4 - 1 5 . . 5 2 14 . 6 1 8 . 7 0 - 2 2 . 7 3 3 0 , . 6 4 1 5 . . 3 5 - 5 3 . 7 1 1 3 5 . , 4 7 5 8 . 6 2 - 2 6 0 . 5 8 2 1 1 0 2 . . 0 7 8 5 . 5 4 - 1 2 0 . . 0 6 3 6 , . 4 8 3 0 . 9 0 - 4 2 . 7 0 1 1 9 . . 5 7 9 0 , . 8 2 - 1 5 3 . 8 3 2 7 8 . . 0 7 2 1 1 . 9 7 - 3 5 6 . 6 6 2 2 1 4 4 . . 4 7 1 2 4 . 9 2 - 1 6 5 . , 4 5 5 5 , . 5 9 4 5 . 8 7 - 6 6 . 5 8 1 1 9 . . 7 9 8 8 . . 6 4 - 1 5 7 . 5 1 2 8 9 . , 1 7 2 1 6 . 7 4 - 3 7 6 . 1 4 2 3 1 2 . . 6 8 8 . 5 9 - 1 7 . , 5 6 3 . . 3 3 1 . 8 2 - 5 . 4 9 4 0 . . 0 1 1 9 . . 7 8 - 7 0 . 7 4 9 2 . 6 1 4 6 . 3 6 - 1 6 2 . 4 3 2 4 5 0 . 4 4 3 7 . 8 9 - 6 4 . 7 7 1 9 . , 3 8 1 3 . 6 8 - 2 6 , . 4 9 7 2 . . 0 5 4 6 . , 2 2 - 1 0 6 . 0 6 1 6 5 . 1 5 1 0 5 . 6 4 - 2 4 3 . 6 3 2 5 2 4 . . 5 1 1 6 . 8 3 - 3 3 . 6 3 7 . . 9 8 4 . 5 3 - 1 2 . . 8 6 6 2 . , 6 7 3 5 . , 4 5 - 1 0 1 , . 1 2 1 4 3 . 5 9 8 1 . 2 4 - 2 3 1 . 6 8 2 6 5 . 6 6 2 . 9 3 - 9 . 2 9 0 . 5 8 ' 0 . 2 2 - 1 . . 2 2 3 . 0 5 1 . 0 9 - 6 . . 5 4 7 . 2 2 2 . 6 3 - 1 5 . 3 4 2 7 3 9 . 9 6 2 9 . 1 7 - 5 2 . 4 5 1 3 . 9 9 8 . 8 9 - 2 0 . . 7 6 9 7 . 9 8 6 0 . 2 9 - 1 4 8 . . 8 1 2 2 6 . 9 6 1 3 9 . 3 6 - 3 4 5 . 1 9 B a c k t r a n s f o r m e d a v e r a g e o f 5 2 0 . 2 5 m ' q u a d r a t s x 4 . APPENDIX 2 c o n t i n u e d P l o t P C T C O V E R (%) R E P H T ( c m • s h o o t - ' ) S T R H T ( c m • s h o o t - 1 ) B A S D I A ( c m - s h o o t - 1 ) n X 0 . 9 5 C . I . n X 0 . 9 5 C . I . n X 0 . 9 5 C . I . n X 0 . 9 5 C . I . 1 5 2 0 . 3 8 0 . 0 5 - • 1 . 0 1 4 4 1 5 . 4 0 1 2 . 3 6 - • 1 8 . 7 7 4 4 2 5 . 2 6 1 8 . 9 3 - 3 2 . 4 9 4 4 0 . 2 1 0 . 1 8 - 0 . 2 4 2 5 2 9 . 5 7 6 . 2 3 - • 1 3 . 6 4 2 0 8 1 5 . 5 0 1 3 . 6 8 - • 1 7 . 4 3 2 0 9 2 3 . 7 9 2 1 . 1 4 - 2 6 . 6 0 2 0 9 0 . 2 6 0 . 2 4 - 0 . 2 8 3 5 2 17 . 7 3 1 3 . 1 2 -• 2 3 . 0 3 5 6 7 17 . 9 3 16 . 6 7 - • 1 9 . 2 5 5 6 9 2 4 . 2 0 2 2 . 3 9 - 2 6 . 0 8 5 7 0 0 . 3 0 O . 2 9 - o . 3 2 4 5 2 17 . 8 8 1 3 . 3 6 -• 2 3 . 0 6 2 2 5 2 0 . 6 9 1 8 . 6 0 - • 2 2 . 8 8 2 2 7 3 2 . 2 2 2 8 . 8 1 - 3 5 . 8 1 2 2 7 0 . 2 9 0 . 2 7 - o . 3 2 5 5 2 5 1 . 1 3 4 3 . 8 4 - • 5 8 . 9 8 3 5 0 3 0 . 2 1 2 7 . 8 9 - • 3 2 . 6 3 3 5 4 4 7 . 2 2 4 3 . 4 6 - 5 1 . 1 3 3 5 4 0 . 3 9 0 . 3 7 - 0 . 4 1 6 5 2 3 8 . 4 7 3 2 . 7 8 - • 4 4 . 6 1 2 3 7 5 0 . 0 9 4 5 . 5 0 - • 5 4 . 9 1 2 3 7 7 4 . 8 5 6 7 . 5 2 - 8 2 . 5 6 2 3 7 0 . 5 4 0 , . 4 9 - 0 . 5 9 7 5 2 5 0 . 3 3 4 3 . 5 4 - 5 7 . 6 1 8 7 8 3 5 . 0 4 3 3 . 2 5 - 3 6 . 8 8 8 8 1 4 . 3 . 0 8 4 0 . . 8 7 - 4 5 . 3 5 8 8 1 0 . . 4 1 0 . . 3 9 - 0 . . 4 2 8 5 2 1 4 . . 8 3 9 . 3 9 - 2 1 . 5 0 2 6 9 1 9 . 0 6 17 . 0 8 - 2 1 . 1 5 2 6 9 2 7 . 3 0 2 4 . . 2 3 - 3 0 . 5 6 2 6 9 0 . . 2 8 0 . . 2 6 - 0 . . 3 0 9 5 2 0 . . 0 6 0 . 0 0 - 0 . 2 4 1 2 1 7 . 2 1 1 2 . 0 6 - 2 3 . 2 8 1 2 3 4 . 7 6 2 4 . . 0 4 - 4 7 . 4 6 1 2 0 , . 3 4 0 . 2 6 - 0 . . 4 4 1 0 5 2 4 0 . . 1 3 3 2 . 4 5 - 4 8 . 6 3 2 2 1 3 1 . 2 3 2 8 . 5 7 - 3 4 . 0 1 2 2 1 5 9 . 0 6 5 3 . . 7 6 - 6 4 . 6 0 2 2 1 0 . . 4 7 0 . . 4 4 - 0 . . 5 0 1 1 5 2 0 . . 9 5 0 . . 3 6 - • 1 . 8 1 4 3 14 . 8 5 1 2 . 5 9 - • 1 7 . 3 0 4 4 2 4 . 3 9 2 0 . . 3 8 - 2 8 . 7 6 4 3 0 . . 2 4 0 . 2 1 - 0 . . 2 7 1 2 5 2 4 4 . . 0 5 3 5 . . 9 0 - 5 3 . 0 4 2 7 9 4 6 . 4 3 4 1 . 6 5 - 5 1 . 4 8 2 8 0 6 7 . 6 4 6 0 . . 2 7 - 7 5 . 4 3 2 8 0 0 . 4 5 0 . 4 1 ' - 0 . , 4 9 1 3 5 2 2 6 . . 3 8 2 0 . . 2 1 - 3 3 . 3 6 2 1 7 3 0 . 0 7 2 6 . . 7 2 - 3 3 . 6 1 2 1 7 3 9 . 9 8 3 5 . . 2 3 - 4 5 . 0 4 2 1 7 0 . 3 3 0 . 3 1 - 0 . , 3 6 1 4 5 2 0 . 8 5 0 . . 3 6 - 1 . 5 4 5 3 1 9 . . 3 1 1 4 . . 8 8 - 2 4 . 3 2 5 3 2 6 . 8 8 2 0 . 2 2 - 3 4 . 4 9 5 3 0 . 2 5 0 . 2 0 - 0 . 3 0 1 5 5 2 2 8 . 9 8 2 3 . , 6 8 - 3 4 . 8 2 1 8 5 5 2 . , 6 1 4 6 . , 5 3 - 5 9 . 0 6 1 8 6 7 6 . 7 5 6 7 . 2 5 - 8 6 . 8 7 1 8 6 0 . 4 9 0 . 4 4 - 0 . 5 4 2 1 5 2 5 2 . 8 7 4 5 . . 7 2 - 6 0 . 5 4 1 2 9 5 19 . . 7 0 1 8 . . 9 5 - 2 0 . 4 7 1 2 9 6 2 7 . 2 3 2 6 . 14 - 2 8 . 3 3 1 2 9 4 0 . 3 0 0 . 2 9 - 0 . 3 0 2 2 5 2 4 8 . 6 6 4 0 . . 4 2 - 5 7 . 6 5 1 7 5 1 1 5 , . 9 6 1 5 . 4 3 - 1 6 . 5 0 1 7 5 1 2 2 . 6 0 2 1 . 7 9 - - 2 3 . 4 3 1 7 5 0 0 . 3 1 0 . 3 1 - 0 . 3 2 2 3 5 2 1 2 . 2 2 7 . . 7 1 - 1 7 . 7 7 2 0 9 2 7 . . 7 4 2 4 . 4 0 - 3 1 . .31 2 0 9 4 3 . 3 5 3 7 . 9 6 - 4 9 . 0 9 2 0 9 0 . 3 7 0 . 3 5 - - 0 . 4 0 2 4 5 2 3 3 . 5 5 2 5 . 8 1 - 4 2 . 3 0 6 8 2 2 2 . 4 2 2 1 . 2 9 - 2 3 . 5 9 6 8 2 3 2 . 3 0 3 0 . 5 3 - - 3 4 . 1 1 6 8 0 0 . 3 0 0 . 2 9 - 0 . 3 1 2 5 5 2 2 3 . 0 5 1 7 . 0 9 - 2 9 . 9 0 3 9 9 2 8 . 0 2 2 5 . 9 9 - 3 0 . 1 2 3 9 9 3 9 . 0 6 3 6 . 1 1-- 4 2 . 1 2 3 9 9 0 . 3 5 0 . 3 4 - O . 3 7 2 6 5 2 2 . 6 3 1 . 2 6 - 4 . 5 0 . 1 2 6 1 6 . 9 8 1 4 . 6 5 - 1 9 . 4 9 1 2 6 2 4 . . 2 8 2 0 . 8 3 - - 2 8 . 0 0 1 2 6 0 . 2 7 0 . 2 5 - - 0 . 3 0 2 7 5 2 2 6 . 6 2 2 0 . 6 3 - 3 3 . 3 7 6 0 8 2 8 . 2 5 2 6 . 7 7 - 2 9 . . 7 7 6 0 8 4 3 . . 8 7 4 1 . 6 2 - - 4 6 . . 18 6 0 8 0 . 3 4 0 . 3 3 - - 0 . 3 5 APPENDIX 3 C o r r e l a t i o n c o e f f i c i e n t s a m o n g o v e r s t o r y v a r i a b l e s f o r C W H a ( n = 1 0 ) M C C 1 . 0 0 N T R E E S . 9 2 1 . 0 0 N S A P L . 6 9 . 8 7 1 . 0 0 B A . 8 3 . 7 9 . 5 5 1 . 0 0 S U M D I A . 9 3 . 9 7 . 7 9 . 9 1 1 . 0 0 A V G D I A - . 8 1 - . 8 8 - . 7 5 - . 5 3 - . 7 9 1 . 0 0 H T - . 2 6 - . 4 0 - . 5 2 - . 0 6 - . 2 8 . 6 3 1 . 0 0 H B L C . 1 3 . 0 1 - . 2 7 . 2 8 . 1 3 . 2 1 . 8 6 1 . 0 0 C R N D E P - . 6 2 - . 6 0 - . 2 4 - . 6 2 - . 6 5 . 4 9 - . 2 2 - . 6 9 1 . 0 0 D F % # - . 0 1 - . 1 6 - . 4 8 - . 0 2 - . 1 1 . 0 3 . 4 5 . 6 3 - . 5 8 1 . 0 0 WH%# . 0 8 . 3 2 . 6 8 . 0 9 . 2 4 - . 1 8 - . 3 9 - . 5 0 . 4 1 - . 9 0 1 . 0 0 M I S C % # - . 1 6 - . 3 1 - . 2 8 - . 1 2 - . 2 5 . 3 2 - . 2 4 - . 4 4 . 5 0 - . 4 5 . 0 3 1 . 0 0 D F % B A . 2 4 . 0 4 - . 3 8 . 2 3 . 1 3 - . 1 2 . 3 1 . 5 8 - . 6 8 . 9 1 - . 9 2 - . 2 1 WH%BA - . 1 8 . 1 1 . 5 3 - . 17 - . 0 1 - . 0 5 - . 3 4 - . 5 1 . 4 9 - . 7 9 . 9 3 - . 1 1 M I S C % B A - . 1 8 - . 3 8 - . 2 8 - . 1 9 - . 3 3 . 4 3 . 0 1 - . 3 1 . 6 0 - . 5 0 . 1 8 . 7 9 A V G B A D I A - . 9 0 - . 9 2 - . 7 4 - . 6 0 - . 8 4 . 9 7 . 5 2 . 0 8 . 5 9 - . 0 3 - . 1 0 . 2 6 S D I . 8 9 . 8 9 . 6 7 . 9 8 . 9 7 - . 6 6 - . 1 7 . 2 1 - . 6 4 - . 0 6 . 1 5 - . 1 8 B A F B A . 6 9 . 6 4 . 4 0 . 9 0 . 7 8 - . 3 6 - . 0 3 . 2 9 - . 5 1 - . 0 1 . 0 5 - . 0 9 B A F D I A - . 5 1 - . 7 2 - . 8 3 - . 3 4 - . 6 0 . 8 1 . 8 7 . 6 0 . 0 9 . 4 5 - . 5 5 . 1 1 B A F T R E E S . 7 1 . 8 8 . 8 5 . 7 0 . 8 6 - . 7 3 - . 4 7 - . 1 6 - . 3 7 - . 3 5 . 5 1 - . 2 6 B A F S A P L . 6 5 . 7 8 . 5 7 . 7 9 . 8 2 - . 6 2 - . 2 8 . 0 8 - . 5 4 - . 1 6 . 2 6 - . 1 9 B A F B A D I A - . 3 6 - . 6 2 - . 7 3 - . 2 0 - . 4 7 . 7 7 . 8 9 . 6 5 - . 0 2 . 3 8 - . 5 1 . 1 7 B A F S D I . 7 4 . 7 7 . 5 9 . 8 8 . 8 6 - . 5 4 - . 2 0 . 1 1 - . 4 8 - . 1 3 . 2 2 - . 1 4 DOWN . 6 5 . 5 8 . 2 8 . 8 7 . 7 3 - . 4 0 - . 0 6 . 2 3 - . 5 3 . 1 6 - . 1 5 - . 0 6 U P . 5 5 . 5 9 . 4 3 . 7 2 . 6 8 - . 3 5 - . 1 4 . 0 7 - . 3 2 - . 2 3 . 2 7 . 0 2 R I G H T . 5 5 . 5 3 . 3 0 . 7 1 . 6 4 - . 3 9 - . 2 5 . 0 4 - . 4 4 . 0 6 - . 0 9 . 0 4 L E F T . 6 1 . 6 0 . 3 9 . 8 3 . 7 2 - . 3 4 - . 0 1 . 2 1 - . 3 8 - . 1 5 . 2 1 - . 0 8 C E N T E R . 6 1 . 4 6 . 2 8 . 7 5 . 6 1 - . 1 3 . 4 3 . 6 1 - . 5 5 . 2 0 . 1 3 - . 2 0 M C C N T R E E S N S A P L B A S U M D I A A V G D I A H T H B L C C R N D E P DF%# WH%# M I S C % WH%BA - . 9 2 1 . 0 0 M I S C % B A - . 4 2 . 0 4 1 . 0 0 A V G B A D I A - . 2 2 . 0 8 . 3 8 1 . 0 0 S D I . 1 9 - . 1 0 - . 2 6 - . 7 2 1 . 0 0 B A F B A . 2 6 - . 2 3 - . 1 4 - . 4 5 . 8 7 1 . 0 0 B A F D I A . 3 4 - . 4 7 . 2 1 . 7 2 - . 4 7 - . 2 2 1 . 0 0 B A F T R E E S - . 1 5 . 3 1 - . 3 4 - . 7 2 . 7 8 . 7 2 - . 7 6 1 . 0 0 B A F S A P L . 0 7 . 0 6 - . 3 0 - . 6 1 . 8 3 . 8 2 - . 5 6 . 8 7 1 . 0 0 B A F B A D I A . 3 1 - . 4 9 . 3 4 . 6 4 - . 3 4 - . 1 1 . 9 6 - . 7 0 - . 5 0 1 . 0 0 B A F S D I . 1 3 - . 0 5 - . 2 2 - . 5 9 . 9 0 . 9 6 - . 4 7 . 8 8 . 9 0 - . 3 7 1 . 0 0 DOWN . 4 3 - . 3 9 - . 1 9 - . 4 6 . 8 3 . 9 5 - . 2 2 . 6 3 . 7 8 - . 1 4 . 9 1 1 . 0 0 U P . 0 1 . 0 1 - . 0 2 - . 4 0 . 7 2 . 9 1 - . 3 8 . 8 0 . 8 7 - . 2 8 . 9 3 . 8 3 R I G H T . 3 3 - . 3 2 - . 1 1 - . 4 6 . 7 0 . 8 6 - . 3 9 . 6 7 . 7 6 - . 3 0 . 8 7 . 9 0 L E F T . 0 8 - . 0 6 - . 0 7 - . 4 0 . 8 0 . 9 5 - . 2 4 . 7 4 . 8 6 - . 1 5 . 9 4 . 8 8 C E N T E R . 3 6 - . 3 1 - . 2 0 - . 2 8 . 6 9 . 6 5 . 2 0 . 2 7 . 2 8 . 3 1 . 5 2 . 5 8 D F % B A WH%BA M I S C % B A A V G B A D I A S D I B A F B A B A F D I A B A F T R E E S B A F S A P L B A F B A D I A B A F S D I D O W N U P 1 . 0 0 R I G H T . 8 6 1 . 0 0 L E F T . 9 4 . 7 6 1 . 0 0 C E N T E R . 3 2 U P . 3 0 R I G H T . 5 2 L E F T 1 . 0 0 C E N T E R APPENDIX 4 C o r r e l a t i o n c o e f f i c i e n t s among o v e r s t o r y v a r i a b l e s f o r CWHbi (n=5) MCC 1 .OO NTREES . 49 1 .00 NSAPL - . 14 .58 1 .00 BA .89 .82 . 16 1 .00 SUMDIA .60 .99 .48 .89 1 .00 AVGDIA .49 - .46 - . 75 . 13 -.31 1 .00 HT .66 .66 - . 16 . 75 .70 -.02 1 .00 HBLC .58 .82 . 10 .77 .82 - .25 .97 1 .00 CRNDEP - .07 - .88 - .84 - .45 - .79 .82 -.37 - .60 1 .00 DF%# - .60 .40 .71 - . 19 .27 - .94 - . 12 . 1 1 - . 73 1 .00 WH%# .62 - . 36 - . 73 .21 - . 24 .89 . 22 - .01 .69 -.99 1 .00 MISC%# . 13 - .42 - . 15 - .07 - . 32 .67 -.60 - .68 .55 -.49 .36 1 .00 DF%BA - .65 . 34 .68 - .25 .21 - .94 - . 16 .06 - .69 .99 - .99 - .48 WH%BA .66 -.33 - .68 .26 - .20 .91 .20 - .02 .67 -.99 .99 .42 MISC%BA .63 - . 36 - .68 . 24 - .22 .97 .09 - . 13 .72 -.99 .96 . 58 AVGBADIA . 52 -.48 - . 73 . 1 1 -.34 .98 .01 - . 23 .80 -.99 .96 .60 SDI .81 .90 .28 .99 .95 - .03 . 75 .81 - .58 -.03 .06 - . 16 BAFBA .93 . 54 - . 21 .86 .63 . 33 .87 .79 - . 15 - .50 .57 - . 21 BAFDIA . 58 - . 41 - .63 . 18 - . 28 .96 - .01 - . 22 . 74 - .98 .94 .65 BAFTREES .40 .87 .48 .64 .81 - .57 . 76 .89 - .84 . 36 - . 26 -.74 BAFSAPL .58 .41 . 50 .50 .40 - .02 . 15 . 23 - . 37 - . 22 . 22 .09 BAFBADIA . 39 - . 58 - . 75 -.01 - .45 .99 - . 15 - . 38 .88 -.94 .89 .69 BAFSDI .85 .72 .01 .88 . 76 .06 .93 .91 - .40 - . 25 . 34 -.41 DOWN . 79 .51 - . 37 . 77 .60 .28 .95 .85 -.11 - . 39 .47 - . 36 UP .85 . 15 - .43 .58 . 24 . 55 .65 . 50 . 20 - . 77 .83 - .06 RIGHT .93 . 18 - .43 .68 .30 .68 .60 .44 . 23 -.82 .85 . 15 LEFT .90 .51 - .27 .81 .59 .33 .90 .80 - . 12 - .50 .58 - .27 CENTER .77 .86 . 16 .91 .89 -.11 .92 .95 - . 58 - .04 . 12 -.46 MCC NTREES NSAPL BA SUMDIA AVGDIA HT HBLC CRNDEP DF%# WH%# MISC%, WH%BA - .99 1 .00 MISC%BA - .99 .98 1 .00 AVGBADIA -.98 .97 .99 1 .00 SDI - . 10 . 10 .08 - .04 1 .00 BAFBA -.55 . 58 .49 . 39 .80 1 .00 BAFDIA - .98 .97 .99 .99 .03 .41 1 .00 BAFTREES .32 - .27 - .40 - .49 •72 .59 - .45 1 .00 BAFSAPL - . 24 . 27 .20 . 12 ^48 .47 . 23 .46 1 .00 BAFBADIA -.92 .90 .96 .98 - . 17 .22 .96 - .65 .02 1 .00 BAFSDI - . 30 . 34 . 23 . 12 .86 .96 . 15 .79 .50 - .05 1 .00 DOWN - .43 .46 . 38 .29 .73 .92 . 28 .56 . 14 . 16 .91 1 .00 UP - . 79 .83 . 72 .66 .48 .90 .67' . 32 . 49 . 50 . 78 . 78 RIGHT - .85 .87 .81 .74 -.56 .90 .76 .21 . 48 .61 . 75 . 77 LEFT - . 54 .58 .48 .39 .76 .99 .40 .58 .40 . 22 .96 .96 CENTER - . 10 . 13 .04 -.08 .93 .89 - .04 .86 .45 -.23 .97 .86 DF%BA WH°/„BA MISC%BA AVGBADIA SDI BAFBA BAFDIA BAFTREES BAFSAPL BAFBADIA BAFSDI DOWN UP 1 .00 RIGHT . .96 1 .00 LEFT .90 .89 1 .00 CENTER .61 UP .60 RIGHT .87 LEFT 1 .00 CENTER o APPENDIX 5 C o r r e l a t i o n c o e f f i c i e n t s among o v e r s t o r y v a r i a b l e s f o r CWHba (n=7) MCC 1 .00 NTREES .88 1 .00 NSAPL .90 . 73 1 .00 BA .82 .92 .60 1 .00 SUMDIA .86 . 98 .67 .98 1 .00 AVGDIA . 29 . 24 . 10 .58 .42 1 .00 HT .56 .44 . 38 .70 .59 .93 1 .00 HBLC .94 .81 .95 .68 .76 . 18 .48 1 .00 CRNDEP .01 -.05 -.21 .34 . 15 .94 .81 - . 13 1 .00 DF%# - .91 -.84 - . 74 -.82 - .85 - .46 - . 72 - .89 - . 21 1 .00 WH%# .90 .91 . 77 . 79 .87 .20 .47 .92 - .08 - .94 1 .00 msc%# . 34 .08 . 17 . 37 . 24 .86 .91 .25 .86 - .49 . 18 1 .00 DF%BA - .86 -.70 - .84 - .63 - .68 - .31 - .59 - .95 -.03 .93 - .90 - .40 WH%BA .87 .85 .82 .66 .77 .06 . 36 .94 - . 23 - .89 .98 .08 MISC%BA . 37 .02 .41 .21 . 12 .66 . 76 .44 . 56 - .49 . 24 .83 AVGBADIA . 34 . 26 . 15 .61 .44 .99 .92 .21 .90 - .48 . 22 .85 SDI .84 .94 .63 .99 .99 .53 .66 .71 . 27 - .83 .82 .32 BAFBA .90 .84 .74 .94 .91 .66 .83 .80 . 40 - .91 .81 .58 BAFDIA .49 . 25 .41 . 52 . 39 .89 .95 .44 . 78 - .60 .32 .94 BAFTREES .94 .93 .83 . 77 .87 .08 . 36 .92 - . 21 - .88 .97 .08 BAFSAPL .61 . 58 .36 .47 .54 -.11 .08 .38 - . 16 - .43 .48 .02 BAFBADIA . 28 . 16 . 17 .51 .34 .97 .90 . 18 .90 - .40 . 12 .86 BAFSDI .94 .89 . 78 .94 .93 .56 .76 .85 .29 - .94 .87 .50 DOWN .93 .85 .84 .91 .90 .55 .74 .85 . 27 - .87 . 79 .48 UP . 78 .67 . 58 .87 .79 .79 . 88 .61 . 59 -.78 .61 .71 RIGHT .80 . 75 .66 .89 .83 .62 .70 .63 . 37 - .69 .61 .46 LEFT . 78 .66 .65 .74 . 72 .62 .84 . 75 .45 - .87 .71 .71 CENTER .89 . 79 .71 .83 .83 .56 .81 .85 . 34 - .98 .87 .61 MCC NTREES NSAPL BA SUMDIA AVGDIA HT HBLC CRNDEP DF%y WH%# MISC%# WH°/oBA - .92 1 .00 MISC%BA - .61 . 26 1 .00 AVGBADIA - . 34 .09 .67 1 .00 SDI - .65 .70 . 18 .55 1 .00 BAFBA - . 79 . 72 . 50 .69 .93 1 .00 BAFDIA - .56 .25 .89 .89 .48 .73 1 .00 BAFTREES - .83 .95 . 13 . 12 .81 .79 . 23 1 .00 BAFSAPL - . 22 . 40 -.26 -.06 .50 .43 - .04 .64 1 .00 BAFBADIA - .31 .01 . 74 .98 .45 .62 .92 .02 - . 19 1 .00 BAFSDI - .82 .79 .45 .60 .94 .99 .65 .86 .48 .52 1 .00 DOWN - .78 .73 . 46 .58 .91 .97 .68 .80 .43 .55 .97 1 .00 UP - .63 .49 . 57 .84 .85 .95 .81 .60 . 39 .78 .91 .89 RIGHT - . 56 .50 . 37 .69 .88 .91 .63 .65 .43 .64 .89 .90 LEFT - . 77 .65 .60 .58 .73 .87 . 78 .65 . 33 .57 .86 .86 CENTER - .88 .80 .55 .57 .83 .93 . 70 .82 .45 .50 .95 .89 DF%BA WH%BA MISC%BA AVGBADIA SDI BAFBA BAFDIA BAFTREES BAFSAPL BAFBADIA BAFSDI DOWN UP 1 .00 RIGHT .94 1 .00 LEFT . 77 .62 1 .00 CENTER .83 UP .71 RIGHT .94 LEFT 1 .00 CENTER APPENDIX 6 C o r r e l a t i o n c o e f f i c i e n t s a m o n g o v e r s t o r y v a r i a b l e s f o r a l l t h r e e v a r i a n t s ( n = 2 2 ) M C C 1 . 0 0 N T R E E S . 8 5 1 . 0 0 N S A P L . 4 6 . 5 6 1 . 0 0 B A . 7 4 . 6 9 . 0 1 1 . 0 0 S U M D I A . 8 5 . 9 3 . 3 3 . 9 0 1 . 0 0 A V G D I A - . 2 1 - . 4 1 - . 6 1 . 2 7 - . 1 0 1 . 0 0 H T . 0 7 - . 0 8 - . 4 2 . 4 0 . 17 . 7 4 1 . 0 0 H B L C . 2 8 . 1 7 - . 3 2 . 5 4 . 3 8 . 4 9 . 8 8 1 . 0 0 C R N D E P - . 4 7 - . 4 8 - . 0 3 - . 4 6 - . 5 2 . 1 9 - . 1 8 - . 6 3 1 . 0 0 D F % # - . 3 5 - . 2 5 - . 2 9 - . 2 5 - . 2 4 - . 1 6 . 0 8 . 2 7 - . 4 3 1 . O O WH%# . 3 7 . 3 4 . 3 5 . 2 2 . 2 7 . 0 4 - . 0 7 - . 1 9 . 2 8 - . 9 3 1 . 0 0 M I S C % # . 0 5 - . 1 6 - . 0 5 . 1 3 - . 0 3 . 3 2 - . 0 5 - . 2 6 . 4 6 - . 4 4 . 0 7 1 . 0 0 D F % B A - . 1 5 - . 0 4 - . 2 0 - . 0 6 - . 0 1 - . 2 2 . 0 2 . 2 5 - . 4 8 . 9 2 - . 9 2 - . 2 3 WH%BA . 1 3 . 1 6 . 2 4 . 0 5 . 0 8 . 1 1 - . 0 5 - . 2 1 . 3 4 - . 8 2 . 9 4 - . 0 7 M I S C % B A . 1 0 - . 2 4 . 0 1 . 0 6 - . 14 . 3 2 . 0 6 - . 2 0 . 4 9 - . 5 8 . 3 3 . 7 4 A V G B A D I A - . 2 2 - . 4 2 - . 6 1 . 2 6 - . 1 2 . 9 8 . 6 8 . 4 2 . 2 3 - . 2 2 . 1 2 . 2 9 S D I . 8 0 . 7 9 . 1 2 . 9 9 . 9 6 . 1 4 . 3 1 . 4 9 - . 4 9 - . 2 5 . 2 4 . 0 8 B A F B A . 6 8 . 5 4 - . 1 1 . 9 3 . 7 8 . 3 9 . 4 9 . 5 9 - . 4 1 - . 2 8 . 2 6 . 1 3 B A F D I A . 0 6 - . 3 2 - . 5 2 . 3 5 - . 0 4 . 8 2 . 7 0 . 5 6 - . 0 1 - . 1 5 . 0 5 . 2 6 B A F T R E E S . 7 0 . 8 8 . 5 3 . 5 5 . 7 9 - . 4 1 - . 14 . 0 7 - . 3 6 - . 3 3 . 4 5 - . 1 9 B A F S A P L . 2 7 . 3 5 . 6 4 - . 1 3 . 1 3 - . 6 1 - . 4 1 - . 3 4 . 0 2 - . 1 5 . 1 9 - . 0 7 B A F B A D I A - . 0 2 - . 3 5 - . 5 9 . 3 1 - . 0 5 . 8 8 . 8 2 . 6 7 - . 0 3 - . 0 1 - . 0 9 . 2 6 B A F S D I . 7 5 . 6 8 . 0 4 . 9 2 . 8 6 . 2 1 . 3 6 . 5 0 - . 4 3 - . 3 1 . 3 2 . 0 7 DOWN . 6 4 . 5 0 - . 1 6 . 8 6 . 7 2 . 3 8 . 4 9 . 6 0 - . 4 2 - . 1 9 . 17 . 0 8 U P . 5 8 . 4 2 - . 1 8 . 8 0 . 6 3 . 3 7 . 3 9 . 4 5 - . 3 0 - . 3 8 . 3 6 . 1 5 R I G H T . 6 2 . 4 4 - . 1 5 . 8 6 . 6 8 . 4 2 . 3 6 . 4 6 - . 3 6 - . 2 7 . 2 2 . 2 1 L E F T . 5 9 . 4 7 - . 1 8 . 8 2 . 6 8 . 3 4 : 4 9 . 5 6 - . 3 6 - . 3 0 . 3 0 . 0 6 C E N T E R . 7 0 . 6 0 . 1 3 . 8 7 . 7 9 . 2 6 . 5 4 . 6 2 - . 4 1 - . 2 0 . 17 . 1 3 M C C N T R E E S N S A P L B A S U M D I A A V G D I A H T H B L C C R N D E P D F % # WH%# M I S C % # WH%BA - . 9 3 1 . 0 0 M I S C % B A - . 5 6 . 2 1 1 . 0 0 A V G B A D I A - . 3 1 . 2 1 . 3 3 1 . 0 0 S D I - . 0 5 . 0 6 - . 0 1 . 1 3 1 . 0 0 B A F B A - . 1 3 . 0 9 . 1 3 . 3 9 . 9 0 1 . 0 0 B A F D I A - . 2 2 . 0 6 . 4 2 . 8 3 . 2 2 . 4 7 1 . 0 0 B A F T R E E S - . 1 5 . 2 9 - . 2 5 - . 4 0 . 6 5 . 5 4 - . 4 1 1 . 0 0 B A F S A P L - . 0 1 . 0 5 - . 0 8 - . 6 0 - . 0 3 - . 2 1 - . 4 7 . 3 6 1 . 0 0 B A F B A D I A - . 0 6 - . 1 0 . 3 6 . 8 3 . 1 8 . 4 2 . 9 3 - . 4 6 - . 5 5 1 . 0 0 B A F S D I - . 1 3 . 1 4 . 0 4 . 2 2 . 9 2 . 9 7 . 2 7 . 7 1 . 0 9 . 2 1 1 . 0 0 DOWN - . 0 4 . 0 4 . 0 3 . 3 8 . 8 3 . 9 5 . 4 3 . 4 9 - . 2 5 . 4 1 . 9 3 1 . 0 0 U P - . 2 6 . 2 0 . 2 2 . 4 0 . 7 6 . 9 4 . 4 7 . 5 2 - . 2 0 . 3 7 . 9 2 . 8 8 R I G H T - . 1 2 . 0 7 . 1 7 . 4 3 . 8 2 . 9 4 . 5 0 . 4 3 - . 2 2 . 4 1 . 9 0 . 9 0 L E F T - . 18 . 1 6 . 1 0 . 3 5 . 7 9 . 9 4 . 4 0 . 5 6 - . 2 1 . 3 7 . 9 3 . 9 3 C E N T E R - . 0 3 . 0 1 . 1 0 . 2 2 . 8 6 . 8 3 . 3 7 . 4 8 - . 0 6 . 3 5 . 8 1 . 7 3 D F % B A WH%BA M I S C % B A A V G B A D I A S D I B A F B A B A F D I A B A F T R E E S B A F S A P L B A F B A D I A B A F S D I DOWN U P 1 . 0 0 R I G H T . 9 3 1 . 0 0 L E F T . 9 3 . 8 3 1 . 0 0 C E N T E R . 6 4 U P . 6 7 R I G H T . 6 9 L E F T 1 . 0 0 C E N T E R to 143 APPENDIX 7 A l l o m e t r i c e q u a t i o n s f o r s t a n d i n g c r o p f o l i a r and t o t a l b i o m a s s o f s a l a l A l l o m e t r i c r e l a t i o n s h i p s were d e t e r m i n e d from a random sample o f s h o o t s s e l e c t e d t o be r e p r e s e n t a t i v e o f t h e r a n g e o f s h o o t s i z e s . C u r r e n t a n n u a l g r o w th l e a v e s and t w i g s were removed and d i s c a r d e d . A l l l i v i n g o l d e r l e a v e s were s e p a r a t e d f r o m stem m a t e r i a l , d r i e d a t 65 °C f o r 24 h o u r s and w e i g h e d t o t h e n e a r e s t 0.01 g. Stem m a t e r i a l was c u t i n t o s m a l l p i e c e s f o r q u i c k e r d r y i n g and d r i e d a t 65 °C f o r 48 h o u r s and w e i g h e d . E q u a t i o n s r e l a t i n g f o l i a r b i o m a s s and s t e m + f o l i a r b i o m a s s ( t o t a l s t a n d i n g c r o p b i o m a s s ) were d e v e l o p e d w i t h b a s a l d i a m e t e r , s t r e t c h h e i g h t , and v a r i o u s c o m b i n a t i o n s o f t h e s e two u s e d as i n d e p e n d e n t v a r i a b l e s . S l o p e and e q u a t i o n t e s t s among a l l e q u a t i o n s d e v e l o p e d f o r i n d i v i d u a l p l o t s were p e r f o r m e d on l n - l n t r a n s f o r m e d e q u a t i o n s . S e p a r a t e t e s t s were made w i t h l n ( B A S D I A ) and l n ( B A S D I A 2 • S T R H T ) as i n d e p e n d e n t v a r i a b l e s . S i g n i f i c a n t d i f f e r e n c e s (p < 0.05) were f o u n d among e q u a t i o n s i n a l l c a s e s e x c e p t f o r e q u a t i o n s d e v e l o p e d i n p l o t s 21, 22, and 24 w h i c h were s a m p l e d i n t h e same s t a n d . A l l o m e t r i c e q u a t i o n s were d e v e l o p e d f o r e a c h p l o t u s i n g l n t r a n s f o r m e d v a r i a b l e s , u n t r a n s f o r m e d v a r i a b l e s , and f o r a n o n l i n e a r f u n c t i o n . I n d i c e s of d e t e r m i n a t i o n (i2; E z e k i e l and Fox 1970) and s x ' s were computed f o r l n t r a n s f o r m e d e q u a t i o n s . A c o m b i n a t i o n o f f o r w a r d and b a c k w a r d s t e p w i s e r e g r e s s i o n was u s e d t o i d e n t i f y t h e b e s t s i m p l e o r m u l t i p l e 144 l i n e a r r e g r e s s i o n f o r e a c h d a t a s e t . D e r i v a t i v e - f r e e n o n l i n e a r r e g r e s s i o n s o f t h e f o r m a•(BASDIA2•STRHT)* were computed w i t h a FORTRAN s u b r o u t i n e (Moore 1984). From t h e s e t s o f e q u a t i o n s d e v e l o p e d f o r e a c h p l o t t h e e q u a t i o n h a v i n g t h e l o w e s t sy,x w a s s e l e c t e d t o be u s e d . Log t r a n s f o r m e d e q u a t i o n s were n e v e r b e t t e r t h a n u n t r a n s f o r m e d e q u a t i o n s , b u t t h e y d i d meet t h e a s s u m p t i o n o f h o m o g e n e i t y of v a r i a n c e w h i l e u n t r a n s f o r m e d and power e q u a t i o n s were s t r o n g l y h e t e r o s c e d a s t i c . Time and l o g i s t i c c o n s t r a i n t s p r e v e n t e d c l i p p i n g o f s a l a l s h o o t s i n many p l o t s . E q u a t i o n s a p p l i e d t o unsampled p l o t s were b a s e d on p l o t s e i t h e r i n s i m i l a r g e o g r a p h i c l o c a t i o n s or w i t h s i m i l a r g r o w t h form of s a l a l . S a l a l g r o w t h form was v e r y d i f f e r e n t among t h e p l o t s u s e d t o d e v e l o p a l l o m e t r i c e q u a t i o n s , b u t a l l unsampled p l o t s had s h o o t g r o w t h form s i m i l a r t o t h o s e p l o t s s a m p l e d . The f o l l o w i n g t a b l e p r e s e n t s t h e b e s t e q u a t i o n s f o u n d and p l o t s t o w h i c h t h e e q u a t i o n s were a p p l i e d f o r e s t i m a t e s o f f o l i a r a nd t o t a l s t a n d i n g c r o p b i o m a s s . E z e k i e l M. and K.A. Fox. 1970. Methods o f c o r r e l a t i o n and r e g r e s s i o n a n a l y s i s . 3 r d e d . J o h n W i l e y and Sons, I n c . New Y o r k , NY. Moore, C. 1984. UBC CURVE. C o m p u t i n g C e n t r 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 , B.C. 1 45 APPENDIX 7 S a l a l s t a n d i n g c r o p f o l i a r and t o t a l b i o m a s s a l l o m e t r i c e q u a t i o n s . Y1=F0LBI0M ( g « s h o o t " 1 ) , Y2=TOTBIOM ( g . s h o o t " 1 ) , X1=BASDIA, X2=STRHT, X3=X1 2, X4=X2 2, X 5 = X 1 « X 2 , X6=X3-X2, X7=X1-X4, X8=X3-X4 P l o t s sampled E q u a t i o n n R2 s ^a Y1 = 0.02539-X2 42 0. 40 0. 66 1 Y2 = 0.3957-X5-0 .00224-X7 42 0. 76 1 . 36 2b Y1 = 0.2921-X5-0 0.4598-X6+0 .000759-X4-.00297-X8 1 17 0. 52 0. 60 2 Y2 = 7.512-X3-0. 1.352-X6+0. 00489-X4+0. 01 2 8 1 « X 7 7451-X5-1 1 7 0. 87 1 . 57 3 C Y1 = 0.31695-X6 0 ' 6 0 9 6 8 97 0. 53 0. 59 3 Y2 = 1.10036-X6 0 • 7 6 6 3 7 97 0. 88 1 . 35 Y1 = 0.39828-X6 0 • 7 8 1 7 0 76 0. 77 1 . 53 4 Y2 = 0.89957-X6 0 • 9 1 8 9 7 76 0. 93 3. 15 5 e Y1 = 0.40376-X6 0 • 7 2 2 0 9 93 0. 81 3. 05 5 Y2 0.99106-X6 0 • 8 3 6 8 H 93 0. 90 9. 31 Y1 = 0.07619-X6 1 • 0 3 1 6 7 32 0. 95 2. 1 1 10 Y2 = 0.42300-X6 0 ' 9 8 0 5 3 32 0. 98 5. 02 1 5s Y1 = 0.02246-X6 1 • 1 5 9 8 4 49 0. 85 10. 10 15 Y2 = 0.01716-X6 1 • 4 9 1 3 2 49 0. 85 81 . 31 ,22,24^ Y1 = -0.000784-X4+0.1208-X5-0.1942-X6+0.00352-X7 151 0. 85 1 . 16 ,22,24 Y2 = 0.6287-0.1024-X2+0.3971 0 . 3 6 1 7 ^ X 6 + 0 . 0 0 5 1 0 « X 7 •X5-151 0. 93 1 . 86 ^ E q u a t i o n u s e d f o r p l o t s 1, 9, and 11. ^ E q u a t i o n u s e d f o r p l o t 2. c E q u a t i o n u s e d f o r p l o t 3. ^ E q u a t i o n u s e d f o r p l o t s 4 and 8. ^ E q u a t i o n u s e d f o r p l o t s 5, 6, and 7. f J E q u a t i o n u s e d f o r p l o t s 10, 13, and 14. ^ E q u a t i o n u s e d f o r p l o t s 12 and 15. E q u a t i o n u s e d f o r p l o t s 21 - 27. APPENDIX 8 A v e r a g e b i o m a s s ( i n grams) o f s a l a l l e a v e s by p l o t and 95% c o n f i d e n c e i n t e r v a l s ( b a c k t r a n s f o r m e d from s q u a r e r o o t ) P l o t n X 0.95 C o n f i d e n c e i n t . 1 330 0.0987 0.0914 - 0.1062 2 315 0. 1239 0.1148 - 0.1333 3 847 0.1133 0.1082 - 0. 1184 4 506 0.1432 0.1352 - 0.1513 5 646 0.2306 0.2188 - 0.2426 6 620 0.2429 0.2324 - 0.2536 7 672 0.1941 0.1839 - 0.2047 8 653 0.1294 0.1215 - 0.1375 9 1 62 0.0728 0.0644 - 0.0817 10 11° 792 0.1831 0.1745 - 0.1919 1 2 • 865 0.2049 0.1954 - 0.2147 1 3 809 0.1774 0.1700 - 0.1850 1 4 583 0.1359 0. 1286 - 0.1434 1 5 922 0.1839 0.1762 - 0.1918 21 1 1 87 0.1338 0.1281 - 0.1395 22 1 450 0.1204 0.1154 - 0.1256 23 1 245 0.1118 0.1075 - 0.1161 24 1115 0.1303 0.1244 - 0.1363 25 1 003 0.1394 0.1337 - 0.1453 26 627 0.0935 0.0887 - 0.0985 27 1 094 0.1524 0.1462 - 0.1587 a L e a f b i o m a s s from UBCRF p l o t 8 was u s e d . 147 APPENDIX 9 R e g r e s s i o n s of s a l a l v a r i a b l e s a g a i n s t p l o t and p r i s m b a s a l a r e a s and s t a n d d e n s i t i e s . Sample s i z e s : CWHa=10, CWHb,=5, CWHb 3 = 7. E q u a t i o n s s i g n i f i c a n t a t p £ 0.05. R e g r e s s i o n e q u a t i o n : Y = bt b ,X Y V a r i a n t X bo b^ r2 s yx DENSITY: CWHa+b, 1/NTREES a N.S.* 1 7731 0.86 6.73 1/BA -14.094 1111.1 0.81 8.02 1/SDI -11 .505 22351.0 0.86 6.97 1/BAFTREES N.S. 19106 0.31 1 4.76 1/BAFBA -23.725 1499.0 0.68 10.47 CWHb 3 1/NTREES -61.237 140890 0.88 19.57 1/BA -25.221 1350.8 0.92 15.71 1/SDI -31 .878 38548.0 0.93 14.96 1/BAFTREES -74.65 158560 0.85 21 .84 1/BAFBA -34.597 1602.6 0.95 12.01 CAGBIOM: A l l 3 1/NTREES• N.S. 1 6807 0.54 12.09 1/BA N.S. 442.33 0.59 1 1 .60 1/SDI N.S. 11170 0.70 10.67 1/BAFTREES N.S. 18784 0.34 14.72 1/BAFBA N.S. 471.21 0.56 1 2.27 FOLBIOM: A l l 3 1/NTREES N.S. 46956 0.42 37.24 1/BA N.S. 1293.1 0.59 31.17 1/SDI N.S. 32432 0.66 29. 1 1 BAFTREES 100.91 -0.03828 0.29 41 .86 BAFBA 135.61 -2.5425 0.57 32.52 TOTBIOM: A l l 3 1/NTREES N.S. 156470 0.52 108.42 1/BA N.S. 3785.9 0.33 128.89 1/SDI N.S. 97566 0.45 1 17.05 BAFTREES 331.49 -0.12924 0.31 133.61 BAFBA 385.04 -6.7463 0.38 126.56 PCTCOVER: A l l 3 NTREES 49.774 -0.0170 0.47 13.66 BA 47.809 -0.63628 0.39 14.66 SDI 50.226 -0.3043 0.44 14.01 BAFTREES 50.373 -0.01850 0.47 13.69 BAFBA 51 .843 -0.78680 0.38 14.75 ! P r e f i x 1/ r e f e r s t o t h e r e c i p r o c a l o f t h e i n d e p e n d e n t v a r i a b l e , ' C o e f f i c i e n t n o t s i g n i f i c a n t (p > 0 . 1 0 ) . 148 < Q _ J < CO < CO 0.6 0.5 H E 3 0.4 H CC UJ h-UJ 0.3 0.2 O . H 0.0 i i t i 4 30 4 0 50 60 70 80 90 100 MEAN CROWN COMPLETENESS (%) A p p e n d i x 10. The r e l a t i o n s h i p o f a v e r a g e b a s a l d i a m e t e r of s a l a l s h o o t s and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . 149 175.0 - i 150.0-I 100 MEAN CROWN COMPLETENESS (%) A p p e n d i x 11. The r e l a t i o n s h i p o f t w i g p r o d u c t i v i t y (# CAG t w i g s ) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . E q u a t i o n : #CAGtwigs •nr 2 = 193.81 -219.93-MCC r 2 = 0 . 9 l , s # =10.7. 150 20.0 n A p p e n d i x 12. The r e l a t i o n s h i p o f s a l a l b a s a l a r e a (cm 2/m 2) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . E q u a t i o n : B a s a l a r e a = 20.57 - 22.8 0 » M C C r 2 = 0 . 7 6 , 151 APPENDIX 13 The r e l a t i o n s h i p of s a l a l s h o o t p o s t u r e t o mean crown c o m p l e t e n e s s The r e l a t i o n s h i p between s a l a l s h o o t p o s t u r e and o v e r s t o r y c o v e r was i n v e s t i g a t e d . An a v e r a g e p l o t i n d e x of p o s t u r e t e r m e d " f l i m s i n e s s i n d e x " ( F I ) was d e r i v e d from s h o o t h e i g h t s by: FI = (Z((STRETCH-REPOSE)/STRETCH)/n)•100 FI i n d i c a t e s t h e a v e r a g e p e r c e n t o f e a c h s h o o t t h a t i s r e d u c e d f r o m t h e p o t e n t i a l maximum s h o o t r e p o s e h e i g h t (FI = 0 i f a l l s h o o t s i n a p l o t have r e p o s e h e i g h t = s t r e t c h h e i g h t ) . The r e l a t i o n s h i p o f FI t o MCC i s i l l u s t r a t e d w i t h 95% c o n f i d e n c e i n t e r v a l s ( F i g . 1 3 a ) . A l t h o u g h v a r i a b l e , a s i g n i f i c a n t , p o s i t i v e r e l a t i o n s h i p of p o t e n t i a l " f l i m s i n e s s " t o MCC i s i n d i c a t e d f o r combi n e d d a t a ( r 2 = 0 . 2 9 , 5 ^ ^ = 5 . 6 % , p < 0 . 0 1 ) . A s e c o n d i n d e x a c c o u n t i n g f o r s h o o t s i z e was a l s o c a l c u l a t e d and t h e r e l a t i o n s h i p t o o v e r s t o r y c o v e r n o t e d . T h i s i n d e x , t e r m e d " f l i m s i n e s s i n d e x 2" was d e v e l o p e d f r o m : FI 2 = 2( (STRETCH-REPOSE)/STRETCH/Basal d i a m e t e r ) / / ! FI 2 was s t r o n g l y r e l a t e d t o MCC ( F i g . 13b), i n d i c a t i n g t h a t u n der i n c r e a s i n g MCC, s h o o t s were i n c r e a s i n g l y r e d u c e d from p o t e n t i a l maximum r e p o s e h e i g h t p e r u n i t b a s a l d i a m e t e r . A p p e n d i x 13a. The r e l a t i o n s h i p o f s a l a l s h o o t p o s t u r e ( f l i m s i n e s s i n d e x ) and 95% c o n f i d e n c e i n t e r v a l s t o mean crown c o m p l e t e n e s s . 1.5-i 1.3-1.1-0.9 0.7 0.5 0.3 ffl A A I I I I I I I 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 MEAN CROWN COMPLETENESS (%) A p p e n d i x 13b. The r e l a t i o n s h i p o f s a l a l s h o o t p o s t u r e ( f l i m s i n e s s i n d e x 2) t o mean crown c o m p l e t e n e s s . APPENDIX 14 D i s t r i b u t i o n of r e p o s e h e i g h t s o f s a l a l s h o o t s by p l o t . D i s t r i b u t i o n i s p e r c e n t of s h o o t d e n s i t y i n e a c h h e i g h t c l a s s ' l o t 0-19 20-39 Repose 40-59 h e i g h t 60-79 c l a s s (cm) 80-99 100-119 120 + 1 67.3 26. 1 6.5 0. 0. 0. 0. 2 51 .4 21.9 9.3 2.4 1 .0 0. 0. 3 58.4 26.1 12.1 3.5 0. 0. 0. 4 53.9 27.5 13.5 3.3 1 .6 0. 0. 5 38.2 32.7 15.6 8.3 3.8 1 .3 0.9 6 20.8 19.2 19.6 16.0 10.0 8.4 6.4 7 32.7 27.6 19.5 10.1 6.1 2.3 1 .5 8 55.7 26.2 11.4 4.4 1 .8 0.4 0. 9 61 .6 38.5 0. 0. 0. 0. 0. 10 30.3 42.2 16.3 6.8 4.0 0.4 0.4 1 1 68.2 31.9 0. 0. 0. 0. 0. 12 34.0 16.6 14.2 9.3 10.4 5.4 9.8 13 40.0 29.7 14.6 7.9 2.2 1 .2 3.9 1 4 60.8 25. 1 9.0 3.6 0. 0. 1 .8 1 5 24.0 15.1 15.2 15.7 13.1 5.2 11.2 21 55.6 33.4 8.8 1 .8 0.3 0. 0.1 22 66.3 29. 1 4.3 0.4 0. 0. 0. 23 43.8 27.8 13.9 8.8 3.4 0.9 1 .2 24 50.5 36.2 10.0 2.9 0.2 0.1 0.1 25 40.0 34.3 15.5 6.2 2.2 1 . 1 0.4 26 67.2 24.0 7.6 1 .4 0. 0. 0. 27 35.0 42.2 15.4 4.1 2.4 0.6 0.6 155 APPENDIX 15 Pe r c e n t frequency of o c c u r r e n c e o l s p e c i e s found i n q u a d r a t s S p e c i e i 1 2 3 4 5 6 7 8 Plot n u m b e r 9 10 11 12 1 3 14 15 21 22 2 3 24 2 5 2 6 27 Gauiint'ia shot Ion 21 .2 7 6 . 9 96.2 8 6 . . 5 9 8 . 1 94.2 9 9 . 9 8 0 . 8 1 3 . 5 96.2 3 2 . 7 96.2 9 2 . 3 1 2 . 3 9 2 . 3 9 9 . 9 9 8 . 1 84 .6 9 4 . 2 8 2 . 7 5 5 . 6 66.r Votcimum pan i folium 3 2 . 7 8 4 . 6 3 0 . 8 51 , . 9 3 .8 19.2 4 0 . 4 13 .5 15.4 11.5 4 0 . 4 11 .5 1 .9 9.6 53. 6 86. 5 59.6 3 2 . 7 5 . 8 19.2 6 3 . 5 Mohoni a ntr 9010 19.2 2 1 . 2 1 5 . . 4 3 6 . 5 4 6 . 2 2 1 . 2 13.5 4 6 . 2 17.3 2 8 . 8 61 .5 1 7 . 3 3. 8 1.9 19. 2 21 .2 1 .9 ftubui u r j f n u j 2 3 . 1 59.6 1 3 . . 5 5 . 8 7 . 7 1.9 2 6 . 9 3.6 1.9 1.9 21 . 2 2 3 . 1 7 . 7 3. 8 1.9 1 .9 Ttuga ht 11r opkpt 1« 3 6 . 5 3.6 1 . 9 3. . 8 1.9 11 .5 1 9 . 2 11 .5 1 .9 5.6 5 . 8 7 . 7 3.6 7 . 7 1. 9 1 3 . 5 7 . 7 13 .5 15.4 15.4 1.9 1 . 9 3 . 8 9 . . 6 3 . 8 7 . 7 3 . 8 1 . 9 5 . 8 3 . 8 9. 6 1. 9 5 . 8 1. 9 5 . 8 1.9 11 .5 Thuja plicata 7 . 7 1 .9 .9 3 .8 11 .5 1 .9 1 .9 5. 8 3 . 8 9.6 1 . 9 Cblmopkilo spp. 3 . 8 1 , . 9 9.6 5 . 8 5 . 8 42.3 1 .9 1 .9 1 . 9Goadytra obi onti/ol1 a 7 . 7 Li imeta boftal i I 1.9 3 . 8 1 .9 34. 6 3. 8 9. 6 1.9 15.4 Cr ami noea spp. 1 . 9 1 , .9 3 .8 9 . 6 1 . 9 1 .9 Hi t I oc I un atbijlorum 7 . 7 21 . 2 3 2 . 7 3. 8 1.9 1.9 Ft agaria tpp. 7 . 7 Attn tri t j p p . 1.9 Mai ant hemum diI at at um 1,9 1.9 b'qut s el um s pp. 1 . 9 fot yil i chum mum t um t.9 1.9 1.9 1.9 3 . S i . 9 5 . 8 5 . 8 Lontcira citiota 1.9 7 . 7 4 0 . 4 Viola orbicut at a 1.9 5.0 7 . 7 3 2 . 7 1.9 Trtemalii l a t i f o l i a 7 . 7 19.2 15.4 11.5 Ac hi,1 iriphylla 5 . 8 6 5 . 4 3 . 8 J.9 1.9 Pitridtum aquitinum 36.5 5.8 11.5 1.9 g _ g 3 g Anaphait s mar gari racta t 9 . 2 Sat i x tcouienana 5.8 7 . 7 9 . 6 7 . 7 9 . 6 5.B Chamateyperit noot kai* HIII j j Abiet omebi 1I i 1 9 y g 5 g Pi nus mom i cot a \ _g Pyr ola 1 pp. ' • 9 Hoi a gymnocarpa 13.5 1.9 t , 9 Strtptopus ttrtpiopotdei 3 . 8 Ammtlone hier aimifolia 1.9 Taxut b r t r i f o l i a 1.9 1,9 Hoi odi 1 cut di 1 col or 1.9 Mom 1 a s pp. \ . 9 Eptlabium angut t ( f oi i um 3.9 Mubut tptct abi (11 1,9 3 . 8 1 . 9 3 . 8 APPENDIX 16 Average q u a d r a t (0.25 m 1) d e n s i t y of u n d e r s t o r y s p e c i e s o t h e r than s a l a l Spftcies 1 2 3 4 5 6 7 8 P l o t number 9 10 11 12 13 14 1 5 21 22 23 24 25 26 27 Vaccinium par rl folium 1 .60 1 .B7 1 .04 0.89 0.04 0.19 0. 40 0. .14 0.65 0.12 1.29 0.21 0.10 0. .10 0. 54 0. 88 0. ,77 0 . 35 0. , 1 5 0. .19 0. ,71 kanonta nerrota 0.46 0.48 0.31 0.71 0.98 0.35 0.27 1 .35 0.33 0, .58 1 .94 0. 54 0. ,12 0. ,02 0 .48 0. .52 0. ,02 X v . i i f ur 11 nuj 0.50 1.29 0.23 0.06 0.08 0.02 0.38 0.06 0.02 0.02 0. 58 0. ,27 0. ,15 0 .04 0. .06 0. .04 Tsuga heteropnyl1 a 0.42 0.04 0.08 0.04 0.02 0. 15 0. ,27 0.12 0.02 0.06 0.06 0, .08 0.04 0. OS 0. ,02 0. .13 0 .08 0, .13 0 .15 0. .25 Pteudol luge menitetti 0.02 0.02 0.04 0.10 0.04 0. 08 0.04 0.02 0 .06 0.04 0. ,10 0. ,02 0. .06 0 .02 0, .06 0 .02 0 .12 Thuja pi I eat a 0.08 0.02 0.06 0. ,15 0.12 0.02 0. ,02 0 .06 0, .04 0 .10 0. .02 Cki mepni1 a t pp. 0. 19 0.04 0.27 0.10 0.06 1.42 0.02 0, .02 0 .02 Gaodyere oblongtfolia 0.10 Li i t a t a boreal 11 0.02 0.04 0 .02 1, .60 0, .08 0 .25 0 .02 0 .46 Gremi i i a r a ipp. 0.15 0.04 0.13 0, .15 0, .02 0 .02 Ht tract um el b i l l arum 0.23 0. .58 1, . 17 0 .06 0 . 1 7 0 .02 Progeria ipp. 0.19 Agoterit tpp. 0.04 Mai ant Annum di 1 at et um 0. 10 0.06 Earn j el um ipp. 0.02 Potystictium munition 0.02 0.04 0.02 0.02 0 .04 0 .02 0 .08 0 .08 Lam e era d i l a t e 0.04 0.14 1 .40 Vi ol a or bi cul at a 0.04 0.25 0.21 1 .69 0 .02 T r i e n l e l t i l a t t f o l l a 0.25 0.48 0 .54 0 .42 Achl ys t rtphyl1 a 0.06 2.23 0 .10 0 .02 0 .04 Pleridium aaui1i num 0.58 0.06 0 .12 0.04 0. , 10 0 .04 Anaphalii mar gart t ace a 0 .56 Sal 1 x j caul ertana 0 .08 0 .08 0 .10 0. .08 0 .13 0. ,09 Chamateyparii root tat eHIi s 0.04 Abiet amabi l i s 0.02 Pi nu, mom i col a Pyrcl a ipp. 0.02 Rosa lymnocarpa 0 . 1 9 0.04 0.01 Strtpi opus 11reptopoi dtts 0.13 Ammei anchi tr ai ni fol i a 0.02 Taxus breti/oiia 0.02 0.02 Hot odi i cut discolor 0.02 Mont i a perfoliate 0.08 Epilobium angutIifofiurn 0.04 Sub MI Jptetabi11 s 0.02 0.04 0.02 0.17 157 APPEMDII 17 L i s t of cover c l e s s e * for spec i e s present in p l o t s " 2 i 25 26 27 TWOS: AOI ri omoti 11 $ Al nut i a i f o Ckomotc ppmr 11 moot tot tot 11 ft aut mootIeol o Pt todolimgo miott tn I Totui oriwIfolI 0 Tkujo fli coio Ttugo ktltropkfil* SHRUBS BBd m m i Mat / «ac «r ol ol f ol t o Cktmopkl I a too. Cloiol kammut pjroi I fl orut Lovi I I I M i op. Gout i ktno tkotto* Holtdttcoi 4i t color Li oooto tor tot it Lornctro cl11oio Lycopodl um iff. kokom o otrtoio fol fttitkom moot i M ft tri di *M aami 11 * u A s i a gymoocor po Rubm ipoet obi 11 t Kubui urn nut Solii icoulerigmo Vottintum otol i fol i urn Vaccintum porn folium HSRBS: Ackl f , tri pkyl I o Agotom iff. Aoopkelti mar for I I Otto Epttootum oagutt i fol i um Ftagona ifp. Goodytro ool oogi f el I e Grcmi not a tpp. Httroti um olbt ftorum Mot em ktmum 41 I I K I M *ff Ori km m ttcuoda fyrola tpf. St *tpi oput n r t fiopoi 4*t T r l t o t o i i t l e u f o l i e Tri Hi um o i i n i fl olo orbi cut oio MOSSKS end LICK CMSi Clo4.io tpp. Dlc r ooum I pp. Html Iomti C0*(f 11 MH Hyiocomlum tpltodtot Kt odbt r ft a ortgooo PI egi ot keci mm uodut at mm fbtytriekum / aoiptrioum *k,t i dl a4tt pkm I or tut Mkyt i4i ad*I pkui tn omtt r\ c U s s e s K l i n k e et e t . (I9flt>: • - <\\, I - i - < 5 | , 2 - 5-<2Sl , 3 - 2 5 - « 5 M . 4 - 50-<75\ , 5 - i 7 5 » . 158 APPENDIX 18 R e s u l t s o f s i t e d i a g n o s i s P l o t H y g r o t o p e T r o p h o t o p e G r i d No. S i t e u n i t 1 3 B-C 7 4 2 2-3 B-C 7 2 3 2 B 7 2 4 2-3 B-C 7 2 5 3 B-C 7 4 6 3 B-C 7 2 7 2-3 B-C 7 2-4 8 2-3 B-C 7 2 9 2-3 B-C 7 2 10 2-3 B-C 7 2 1 1 2-3 B 9 2 12 2 B 9 2 13 2-3 B-C 9 2 1 4 2-3 B-C 9 2 15 2 B 9 2 21 2-3 B-C 11 2 22 2-3 B-C 11 2 23 2-3 B-C 11 2 24 2-3 B-C 11 2 25 2-3 B-C 11 2 26 3 B-C 11 2 27 2-3 B-C 1 1 2 APPENDIX 19 R e g r e s s i o n c o e f f i c i e n t s o f e q u a t i o n s p r e d i c t i n g s o l a r r a d i a t i o n c o m p o n e n t s f r o m s t a n d c h a r a c t e r i s t i c s . Sample s i z e s : CWHa=6, CWHb=6. E q u a t i o n s s i g n i f i c a n t a t p £ 0 . 1 0 . R e g r e s s i o n e q u a t i o n : Y = ae Y Subzone X a b / 2 T O T A L : CWHa NTREES BA BAFBA 1 .0716 1.6708 5 .8482 3 . 1 5 3 9 E - 3 0 8 . 6 6 3 9 E - 2 0.1381 0 . 8 9 0 . 9 7 0 . 9 2 0 . 0 6 1 0 0 . 0 3 2 4 0 . 0 4 8 5 CWHb NTREES BA BAFBA 8 . 0 6 7 9 1.3098 1.3583 3 . 5 8 5 0 E - 3 0 .1193 0 . 1 0 9 7 0 .92 0 .84 0 .93 0 . 0 6 2 4 0 . 0 8 8 0 0 . 0 5 7 9 B o t h NTREES BA BAFBA 0 .6640 0 .8840 1.0616 1 . 1225E-3 7 . 2 0 0 5 E - 2 7 . 9 5 6 9 E - 2 0 .63 0 . 7 9 0 .77 0 . 1 1 4 3 0 . 0 8 5 0 0 . 0 8 9 5 D I F F U S E : CWHa NTREES BA 0 .7272 1.2563 5 . 0 9 7 6 E - 4 3 . 7 1 6 7 E - 2 0 .58 0 .66 0 .1527 0 . 1 3 3 9 BAFBA N . S . * 0 .48 0 . 1 7 0 9 CWHb NTREES BA BAFBA 3 . 0 1 6 5 2 .3034 2 .6304 7 . 5 4 5 8 E - 4 3 . 5 1 3 6 E - 2 4 . 3 3 1 0 E - 2 0 .93 0 . 8 9 0 . 8 0 0 . 1598' 0 . 2 0 1 3 0 . 2 7 2 7 DIRECT : CWHa NTREES BA BAFBA 1.3409 2. 1132 11.2441 4 . 2 7 4 9 E - 3 0 .1078 0 .1777 0 . 9 5 0 .98 0 . 9 6 0 . 0 3 9 4 0 . 0 2 4 7 0 . 0 3 5 3 CWHb NTREES BA BAFBA 2 3 0 . 5 5 4 6 2 1 3 . 0 7 9 4 9 .3088 8 . 3 6 3 2 E - 3 0.7341 0 . 3 5 3 6 0 . 9 9 0 .98 0 .98 0 .0204 0 .0263 0 .0247 B o t h NTREES BA BAFBA 0 . 7 0 3 6 0 . 7 0 6 9 0.8231 1 .7435E-3 8 . 5 9 5 2 E - 2 9 . 0 6 1 8 E - 2 0 . 6 9 0 . 5 9 0 . 5 5 0 . 0 8 8 5 0 .1031 0 . 1 0 7 0 PAR: CWHa NTREES BA BAFBA 0 .4157 0 . 8 5 6 9 2 . 2 5 4 9 1 .6161E-3 7 . 4 0 9 0 E - 2 0.1131 0 . 8 6 0 . 9 5 0 . 8 8 0 .0430 0 .0264 0 .0396 CWHb NTREES BA BAFBA 0 . 8 0 9 9 0 .4242 0 .4800 1 . 5 7 4 6 E - 3 6 . 7 0 1 7 E - 2 7 . 1 8 7 5 E - 2 0 .88 0 . 8 5 0 . 8 3 0 .0380 0 . 0 4 1 9 0 . 0 4 4 9 B o t h NTREES BA BAFBA 0 .3845 0 .4213 0.4691 1 .0378E-3 5 . 6 0 0 9 E - 2 6 . 1 0 4 5 E - 2 0 . 7 5 0 . 7 8 0 . 6 8 0 .0515 0.0481 0 . 0 5 7 9 a E x p o n e n t f o r power of 10 . ^ E q u a t i o n no t s i g n i f i c a n t (p > 0 . 1 0 ) . APPENDIX 20 R e g r e s s i o n c o e f f i c i e n t s of e q u a t i o n s p r e d i c t i n g s o l a r r a d i a t i o n c o m p o n e n t s f rom s t a n d c h a r a c t e r i s t i c s . Sample s i z e s : CWHa=6, CWHb=6. E q u a t i o n s s i g n i f i c a n t a t p £ 0 . 0 5 . R e g r e s s i o n e q u a t i o n : Y = Y Subzone X b / 2 s yx T O T A L : CWHa MCC 2 .9899 0 . 8 5 0 . 0 7 1 3 SUMDIA 5 . 5 9 6 5 E - 3 a 0 . 9 5 0 .0414 SDI 2 . 8 7 9 7 E - 3 0 . 9 5 0 . 0 3 9 6 BAFSDI 2 . 7 6 5 9 E - 3 0 . 7 0 0 . 1 0 2 8 CWHb MCC 2 .3816 0 . 6 9 0 . 1232 SUMDIA 4 . 4 9 3 4 E - 4 0 . 8 0 0 . 0 9 8 3 SDI 3 . 5 1 8 5 E - 3 0 . 8 4 0 . 0 8 7 8 BAFSDI 3 . 2 8 7 6 E - 3 0.91 0 . 0 6 6 3 B o t h MCC 2 .6362 0 .73 0 . 0 9 7 4 SUMDIA 4 . 8 1 1 3 E - 4 0 . 8 5 0 . 0 7 2 5 SDI 3 . 2 6 6 5 E - 3 0 . 8 7 0 . 0 6 6 5 BAFSDI 3 . 0 6 0 6 E - 3 0.81 0 .0817 D I F F U S E : CWHa MCC 1.4802 0 .74 0 . 1 2 1 7 SUMDIA 2 . 0 9 4 9 E - 4 0.71 0 . 1 2 8 0 SDI 1.3024E-3 0 . 6 9 0 . 1 3 1 0 BAFSDI N . S . 6 CWHb MCC N . S . SUMDIA N . S . SDI N . S . BAFSDI N . S . DIRECT: CWHa MCC 3 .2988 0 . 8 4 0 .0731 SUMDIA 6 . 4 4 1 9 E - 4 0 . 9 8 0 . 0 2 8 4 SDI 3 . 2 2 6 6 E - 3 0 . 9 5 0 . 0 3 8 9 BAFSDI 3 . 0 3 7 0 E - 3 0 .68 0 . 1 0 1 5 CWHb MCC 3 .2984 0 . 6 6 0 . 1032 SUMDIA 6 . 6 3 9 9 E - 4 0 . 7 0 0 . 0 9 7 0 SDI 5 . 3 1 0 4 E - 3 0 .77 0 .0851 BAFSDI 4 . 8 2 4 0 E - 3 0 . 8 6 0 . 0 6 5 9 B o t h MCC 3 .2985 0 . 7 5 0 .0800 SUMDIA 6 . 5 7 2 5 E - 4 0 .84 0 . 0 8 2 9 SDI 4 . 4 8 1 5 E - 3 0 .73 0 . 0 9 7 5 BAFSDI 4 . 0 3 4 7 E - 3 0 .63 0.0731 PAR: CWHa MCC 3 .7696 0 . 9 5 0 .0270 SUMDIA 8 . 9 5 9 6 E - 4 0 . 7 9 0 . 0 5 2 6 SDI 3 . 9 4 9 8 E - 3 0.91 0 . 0 3 4 6 BAFSDI 3 . 3 9 2 8 E - 3 0 . 8 6 0 . 0 4 2 6 CWHb MCC 3.2611 0 .67 6 .0636 SUMDIA 6 . 6 3 8 9 E - 4 0 .88 0 .0378 SDI 5 . 4 5 1 6 E - 3 0 .74 0 .0564 BAFSDI 4 . 9 2 7 1 E - 3 0 .65 0 .0648 B o t h MCC 3 .4824 0 .79 0 . 0 4 7 3 SUMDIA 7 . 3 0 0 4 E - 4 0 .77 0 . 0 4 9 6 SDI 4 . 9 4 7 7 E - 3 0 .74 0.0521 BAFSDI 4 . 2 7 5 9 E - 3 0 .60 0 . 0 6 4 9 °Exponent f o r power of 10 . ^ E q u a t i o n n o t s i g n i f i c a n t {p > 0 . 0 5 ) . APPENDIX 21 R e g r e s s i o n c o e f f i c i e n t s o f e q u a t i o n s p r e d i c t i n g s a l a l f r o m s i t e f a c t o r s d e r i v e d f r o m h e m i s p h e r i c a l p h o t o g r a p h s . Samp le s i z e s : CWHa=5, CWHb=6. R e g r e s s i o n e q u a t i o n : Y = 1 +°fl(x-c)/fc Y S u b z o n e X a b c 2 s y • X p D E N S I T Y : CWHa D I F F U S E SF 844 .3 1 0 5 . 8 0 . 0920 0 . 96 5 .7 <0 .01 DIRECT SF 3 .3 - 2 . 5 - 0 . 4638 0 . 86 11 .4 <0 .05 CWHb D I F F U S E SF 707 . 9 46781946 0 . 071 1 0 . 92 17 .0 <0 .01 DIRECT SF 1 127 . 5 8 3 9 1 5 . 0 0 . 0889 0 . 55 40 .5 0 .09 B o t h D I F F U S E SF 992 . 5 2 0 8 . 8 0 . 0826 0 . 70 26 .0 <0 .01 DIRECT SF 587 . 6 2 2 5 . 2 0. 0653 0 . 1 3 44 .5 0 .27 SALALBA: CWHa D I F F U S E SF 173 .8 21 .4 0. 0879 0 . 78 3 . 1 <0 .05 DIRECT SF 1 06 . 7 11327 .4 0 . 1 326 0 . 76 3 .2 0 .06 CWHb D I F F U S E SF 60 .5 1 9 1 8 0 . 0 0 . 0623 0 . 89 1 .7 <0 .01 DIRECT SF 94 .2 12179 .0 0 . 0821 0 . 51 3 .7 0 . 11 B o t h D I F F U S E SF 77 .4 5 2 . 9 0 . 0674 0 . 82 2 .2 <0 .01 DIRECT SF 75 . 4 1492B.8 0 . 0872 0 . 47 3 .7 <0 .05 TOTBIOM: CWHa D I F F U S E SF 9560 .0 8 7 9 . 8 0 . 0881 0 . 68 174 .8 0 .09 DIRECT SF 2994 .0 - 1 2 5 2 . 3 0. 1 166 0 . 70 1 68 .3 0 .08 CWHb D I F F U S E SF 5572 .0 3 8 3 . 5 0 . 0689 0 . 79 56 .3 <0 .05 DIRECT SF 0 .90 B o t h D I F F U S E SF 1854 . 3 3 2 1 1 5 2 . 0 0. 0372 0 . 57 131 . 9 <0 .01 DIRECT SF 3133 . 5 4 7 6 2 1 6 . 0 0 . 0917 0 . 53 1 38 .4 <0 .05 CAGBIOM: CWHa D I F F U S E SF 787 . 9 1 0 1 . 0 0 . 0906 0 . 84 12 .0 <0 .05 DIRECT SF 29 . 6 - 9 . 4 - 0 . 0209 0 . 76 14 .3 <0 .05 CWHb D I F F U S E SF 273 . 6 5 0 0 9 6 . 0 0 . 0759 0 . 90 7 .3 <0 .01 DIRECT SF 431 . 9 B475943 0. 0916 0 . 53 16 . 1 0 .10 B o t h D I F F U S E SF 299 . 9 501 .3 0. 0718 0 . 85 9 . 1 <0 . 0 1 DIRECT SF 356 . 6 7 1 7 6 7 . 0 0. 0972 0 . 51 16 .5 <0 .05 PCTCOVER : CWHa D I F F U S E SF 3183 .0 5 4 . 7 0 . 0922 0 . 61 17 . 1 0 .12 DIRECT SF 279 . 9 2 4 6 8 . 1 0 . 0757 0 . 28 23 .0 0 .36 CWHb D I F F U S E SF 581 .8 100 .2 0 . 0671 0 . 93 6 .0 <0 .01 DIRECT SF 322 .2 7 0 2 0 8 . 0 0 . 0501 0 . 33 18 .0 0 .23 B o t h D I F F U S E SF 941 . 1 7 1 . 2 0 . 0730 0 . 67 12 .4 <0 .01 DIRECT SF 223 .7 2 0 4 1 4 . 0 0 . 0281 0 . 24 18 .9 0 .13 162 A p p e n d i x 22. R e l a t i o n s h i p s of s a l a l d e n s i t y ( # « m ~ 2 ) and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l , d i r e c t , d i f f u s e , and d i f f u s e PPFD s o l a r r a d i a t i o n c o mponents. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (BB) . 163 PROPORTION GLOBAL RADIATION TRANSMITTED PROPORTION DIRECT RADIATION TRANSMrTTED A p p e n d i x 23. R e l a t i o n s h i p s o f p e r c e n t c o v e r of s a l a l and 95% c o n f i d e n c e i n t e r v a l s t o t r a n s m i s s i o n of g l o b a l , d i r e c t , d i f f u s e , a nd d i f f u s e PPFD s o l a r r a d i a t i o n c o mponents. D o t t e d l i n e s a r e r e l a t i o n s h i p s i n i n d i v i d u a l s u b z o n e s . CWHa (•), CWHb (ffi). 164 A p p e n d i x 24. R e l a t i o n s h i p s o f s a l a l DENSITY, CAGBIOM, FOLBIOM, TOTBIOM, and PCTCOVER t o R e i n e k e ' s SDI d e r i v e d f r o m p l o t t r e e measurements (SDI) and p r i s m s a m p l e s ( B A F S D I ) . D o t t e d l i n e s a r e s e p a r a t e r e l a t i o n s h i p s i n CWHa and CWHb 3 v a r i a n t s . 

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