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UBC Theses and Dissertations

Vegetation response to right-of-way clearing procedures in coastal British Columbia McGee, Ann Bradshaw 1988

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VEGETATION RESPONSE TO RIGHT-OF-WAY CLEARING PROCEDURES B.Sc, The University of I l l i n o i s , 1977 M.Sc, The University of C a l i f o r n i a , 1979 THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Faculty of Forestry) We accept t h i s thesis as conforming COASTAL BRITISH COLUMBIA By ANN BRADSHAW MCGEE to the required standard The University of B r i t i s h Columbia September 1988 © Ann Bradshaw McGee, 1988 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s m a y b e g r a n t e d b y t h e h e a d o f m y d e p a r t m e n t o r b y h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t b e a l l o w e d w i t h o u t m y w r i t t e n p e r m i s s i o n . 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 1 9 5 6 M a i n M a l l V a n c o u v e r , C a n a d a V 6 T 1 Y 3 D a t e t W . a o ^ ^ D E - 6 ( 3 / 8 1 ) Abstract This research was designed to assess the response of the f l o r a of forested s i t e s to the methods employed by B.C. Hydro and Power Authority for the i n i t i a l c learing of transmission l i n e rights-of-way i n coastal B r i t i s h Columbia. Seven immature forest vegetation units adjacent to, and seven early serai vegetation units on, the transmission l i n e rights-of-way were i d e n t i f i e d . The environmental parameter most highly correlated with both the immature forest and early serai vegetation units was slope p o s i t i o n . The degree of disturbance (clearing standard) and seeding with agronomic grass and legume species complicated the determination of relationships between immature forest and early serai vegetation units. The majority of seeds (72%) i n the forest samples was found in the forest f l o o r layer. Twenty-one percent of the germinable seeds were found i n the 0-5 cm layer of the mineral s o i l , and 7% were found i n the 5-10 cm layer. Fewer germinable seeds were found in samples from d r i e r than from moister vegetation units, regardless of disturbance l e v e l . Seed bank samples from high-disturbance s i t e s had the fewest germinable seeds, primarily because the forest f l o o r had been removed. The seed rain was dominated by tree species within the forests, and shrub and herbaceous species on the rights-of-way. The seed r a i n was greater, and percent germinability was higher, in the second year than i n the f i r s t . Important s p e c i e s v e g e t a t i v e l y i n v a d i n g a f t e r , or r e c o v e r i n g from, p l o t s c a r i f i c a t i o n , i n c l u d e d G a u l t h e r i a s h a l l o n , P t e r i d i u m  aquilinum, and Rubus u r s i n u s . S u c c e s s f u l s e e d l i n g establishment was r a r e : only Alnus rubra, A n a p h a l i s marqaritacea, and Rubus spp. s e e d l i n g s were observed i n s i g n i f i c a n t numbers, but few of these s u r v i v e d t o the next year. In order t o be s u c c e s s f u l i n managing v e g e t a t i o n t o meet t r a n s m i s s i o n l i n e right-of-way (or t r e e production) goals, more a t t e n t i o n must be p a i d t o the b i o l o g y and r e p r o d u c t i v e ecology of pest and a c c e p t a b l e / c r o p s p e c i e s . I f the f i e l d of v e g e t a t i o n management i s to change from a c o r r e c t i v e to a p r e v e n t i v e focus, t h i s a t t e n t i o n , and information,' i s c r u c i a l . i v T a b l e o f C o n t e n t s A b s t r a c t i i Tab l e o f C o n t e n t s i v L i s t of T a b l e s y i L i s t o f F i g u r e s . i x Acknowledgements x i Chapter 1 G e n e r a l I n t r o d u c t i o n . . . 1 1.1 V e g e t a t i o n management 1 1.2 V e g e t a t i o n management on t r a n s m i s s i o n l i n e r i g h t s - o f -way 3 1.2.1 G e n e r a l c o n c e p t s and c o n s i d e r a t i o n s 5 1.2.2 V e g e t a t i o n management on t r a n s m i s s i o n l i n e r i g h t s - o f - w a y i n B r i t i s h Columbia 8 1.3 O b j e c t i v e s o f t h i s s t u d y 11 Chapter 2 P l a n t Community C o m p o s i t i o n and V e g e t a t i o n - E n v i r o n m e n t R e l a t i o n s h i p s 16 2.1 I n t r o d u c t i o n 16 2.2 Methods 18 2.2.1 The s t u d y s i t e s 18 2.2.2 F i e l d methods 22 2.2.3 Data a n a l y s i s 24 2.3 R e s u l t s 30 2.3.1 V e g e t a t i o n c l a s s i f i c a t i o n 30 2.3.2 C a n o n i c a l c o r r e l a t i o n a n a l y s i s 47 2.3.3 D i s c r i m i n a n t a n a l y s i s 53 2.4 D i s c u s s i o n 66 2.4.1 F o r e s t v e g e t a t i o n 66 2.4.2 S e r a i v e g e t a t i o n 67 2.4.3 Immature f o r e s t - e a r l y s e r a i v e g e t a t i o n r e l a t i o n s h i p s 69 2.5 C o n c l u s i o n s 76 Cha p t e r 3 The Seed Bank and Seed G e r m i n a t i o n 77 3.1 I n t r o d u c t i o n 77 3.2 Methods 7 9 3.2.1 The seed bank 7 9 3.2.1.1 The s t u d y s i t e s 79 3.2.1.2 Sample c o l l e c t i o n 80 3.2.1.3 Sample p r e p a r a t i o n and g e r m i n a t i o n regimes 82 3.2.1.4 Data a n a l y s i s 84 3.2.2 Seed g e r m i n a t i o n 84 3.2.2.1 Seed p r e p a r a t i o n and e x p e r i m e n t s 84 3.2.2.2 Data a n a l y s i s 87 3.3 R e s u l t s 88 3.3.1 The seed bank 88 3.3.1.1 S p e c i e s and numbers o f seeds 91 3.3.1.2 F i e l d v e r s u s greenhouse g e r m i n a t i o n . . . .99 3.3.2 Seed g e r m i n a t i o n e x p e r i m e n t s 105 3.4 D i s c u s s i o n 113 3.5 C o n c l u s i o n s 123 V Chapter 4 S p e c i e s C o m p o s i t i o n , V i a b i l i t y , and Se a s o n a l and S p a t i a l P a t t e r n s o f D i s p e r s e d Seed 125 4.1 I n t r o d u c t i o n 125 4.2 Methods 127 4.2.1 The s t u d y s i t e s 127 4.2.2 Seed c o l l e c t i o n and p r o c e s s i n g 128 4.2.3 Data a n a l y s i s 130 4.3 R e s u l t s 132 4.3.1 S p e c i e s c o m p o s i t i o n and v i a b i l i t y 132 4.3.2 Se a s o n a l p a t t e r n s 139 4.3.3 S p a t i a l p a t t e r n s 142 4.4 D i s c u s s i o n 145 4.5 C o n c l u s i o n s 151 Chapter 5 Bud Bank, Seed Bank, Seed R a i n , and E a r l y S u c c e s s i o n i n F o r e s t e d Regions o f C o a s t a l B r i t i s h Columbia 152 5.1 I n t r o d u c t i o n 152 5.2 Methods 154 5.2.1 The s t u d y s i t e s . . . 154 5.2.2 V e g e t a t i o n - t h e bud bank 154 5.2.3 The seed bank 155 5.2.4 The seed r a i n 155 5.2.5 S c a r i f i e d p l o t s 156 5.3 R e s u l t s 156 5.3.1 V e g e t a t i o n - t h e bud bank 156 5.3.2 The seed bank 161 5.3.4 R e v e g e t a t i o n o f s c a r i f i e d p l o t s 164 5.3.4.1 V e g e t a t i v e r e s p r o u t i n g 164 5.3.4.2 I n v a s i o n from seed 169 5.4 D i s c u s s i o n 175 5.5 C o n c l u s i o n s 180 L i t e r a t u r e C i t e d 182 Appendix - L i s t o f p l a n t s p e c i e s 193 V I L i s t o f T a b l e s 1.1 Major complexes o f p o t e n t i a l competing v e g e t a t i o n i n c o a s t a l B r i t i s h Columbia 4 1.2 B r i t i s h Columbia Hydro and Power A u t h o r i t y c l e a r i n g s t a n d a r d s 10 2.1 E n v i r o n m e n t a l and v e g e t a t i o n parameters r e c o r d e d f o r t h e v e g e t a t i o n sample p l o t s 25 2.2 D i a g n o s t i c c o m b i n a t i o n o f s p e c i e s f o r t h e v e g e t a t i o n u n i t s r e c o g n i z e d i n t h e immature f o r e s t s a d j a c e n t t o t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y 33 2.3 Average s t a t u s o f e n v i r o n m e n t a l and v e g e t a t i o n parameters f o r t h e v e g e t a t i o n u n i t s i d e n t i f i e d i n t h e immature f o r e s t a d j a c e n t t o t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y 36 2.4 D i a g n o s t i c c o m b i n a t i o n o f s p e c i e s f o r t h e e a r l y s e r a i v e g e t a t i o n u n i t s r e c o g n i z e d on t h e Cheekye Loop and M a l a s p i n a r i g h t s - o f - w a y 41 2.5 Average e n v i r o n m e n t a l and v e g e t a t i o n parameters f o r t h e v e g e t a t i o n u n i t s i d e n t i f i e d on t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y 43 2.6 C a n o n i c a l c o r r e l a t i o n a n a l y s i s o f immature f o r e s t v e g e t a t i o n (V) and environment (E) d a t a . . 48 2.7 C o r r e l a t i o n c o e f f i c i e n t s r e l a t i n g s p e c i e s t o PCA I - I I I and t o t h e c a n o n i c a l v a r i a t e s V ( v e g e t a t i o n ) and E (environment) f o r t h e f o r e s t d a t a 50 2.8 C a n o n i c a l c o r r e l a t i o n a n a l y s i s o f t h e e a r l y s e r a i v e g e t a t i o n (V) and environment (E) d a t a 54 2.9 C o r r e l a t i o n c o e f f i c i e n t s r e l a t i n g s p e c i e s t o PCA I - I I I and t o t h e c a n o n i c a l v a r i a t e s V ( v e g e t a t i o n ) and E (environment) f o r t h e s e r a i v e g e t a t i o n d a t a 56 2.10 Mean ( s t a n d a r d e r r o r o f t h e mean) Mahalanobis D 2 d i s t a n c e s between t h e immature f o r e s t v e g e t a t i o n u n i t s 58 2.11 Mean ( s t a n d a r d e r r o r o f t h e mean) Mahalanobis D 2 d i s t a n c e s -between t h e s e r a i v e g e t a t i o n u n i t s 61 2.12 Mean ( s t a n d a r d e r r o r of t h e mean) Mah a l a n o b i s D 2 d i s t a n c e s w i t h i n t h e immature f o r e s t and e a r l y s e r a i v e g e t a t i o n ("Age")/ and o f p l o t s t o t h e c e n t r o i d o f t h e u n i t t o which t h e y b e l o n g ("Unit") 64 V I X 2.13 Mean ( s t a n d a r d e r r o r o f t h e mean) Mahalanobis d i s t a n c e s between t h e e a r l y s e r a i p l o t s "(by v e g e t a t i o n u n i t ) and t h e c e n t r o i d s o f t h e f o r e s t v e g e t a t i o n u n i t s 65 2.14 Apparent t r a n s i t i o n s between immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s based on s p e c i e s c o m p o s i t i o n , t o p o g r a p h i c p o s i t i o n , and d i s t u r b a n c e a t t h e two s t u d y s i t e s 72 3.1 The d i s t r i b u t i o n o f seed bank sample p l o t s among t h e r e c o g n i z e d v e g e t a t i o n u n i t s a d j a c e n t t o and on t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y 89 3.2 T o t a l number of germinants ( e x c l u d i n g mosses) emerging from a l l samples of f o r e s t , and low and h i g h d i s t u r b a n c e s e r a i s o i l s i n t h e greenhouse and f i e l d 92 3.3 P e r c e n t c o n s t a n c y o f seed bank s p e c i e s i n t h e f o r e s t e d , low and h i g h d i s t u r b a n c e p l o t s a t t h e two s t u d y s i t e s 97 3.4 Mean number of seeds p e r square meter - s t a n d a r d e r r o r , and c o n s t a n c y (%) o f t h e 15 major seed bank s p e c i e s among t h e s o i l l a y e r s sampled i n t h e f o r e s t e d , low, and h i g h d i s t u r b a n c e p l o t s 98 3.5 D e n s i t y (mean - s t a n d a r d e r r o r p e r square meter) o f t h e 15 major seed bank s p e c i e s among the depths sampled i n each of t h e f o r e s t , low, and h i g h d i s t u r b a n c e v e g e t a t i o n u n i t s . . .100 3.6 Constancy (%) o f moss s p e c i e s i n samples o f immature f o r e s t s o i l s , and low and h i g h d i s t u r b a n c e e a r l y s e r a i s o i l s , as o b s e r v e d under greenhouse and f i e l d ( i n p a r e n t h e s e s ) g e r m i n a t i o n regimes 103 3.7 Comparison of g e r m i n a t i o n , under greenhouse and f i e l d r egimes, o f major seed bank s p e c i e s 104 3.8 A n a l y s i s o f t h e depth X s u b s t r a t e g e r m i n a t i o n e x p e r i m e n t . . . . 106 3.9 A n a l y s i s o f t h e shade X s u b s t r a t e X water g e r m i n a t i o n experiment 110 3.10 A comparison of c o n i f e r o u s f o r e s t seed bank s t u d i e s from t h e l i t e r a t u r e 114 4.1 T o t a l number of seeds a c t u a l l y t r a p p e d , and f r e q u e n c y ( i n p a r e n t h e s e s ) , over t h e two-year s a m p l i n g p e r i o d a t t h e Cheekye Loop and M a l a s p i n a s t u d y s i t e s 133 4.2 The most i m p o r t a n t n a t i v e (or n a t u r a l i z e d ) t a x a , based on t h e number of seeds t r a p p e d , from t h e s t u d y s i t e s by c o n t r i b u t i o n t o t h e seed r a i n on t h e r i g h t - o f - w a y 135 4.3 Mean number of seeds p e r square meter - s t a n d a r d e r r o r , f o r t h o s e s p e c i e s o c c u r r i n g i n a t l e a s t 30% o f t h e r i g h t - o f - w a y or f o r e s t t r a p s a t one o f t h e two s t u d y s i t e s i n one o f t h e two t r a p p i n g y e a r s 136 v i i i 4.4 E s t i m a t e s o f t h e mean number o f g e r m i n a b l e seeds p e r square meter - s t a n d a r d e r r o r o f t h o s e s p e c i e s o c c u r r i n g i n a t l e a s t 30% o f t h e r i g h t - o f - w a y o r f o r e s t t r a p s a t one o f t h e two s t u d y s i t e s i n one of t h e two t r a p p i n g y e a r s 137 4.5 E s t i m a t e s o f seed g e r m i n a b i l i t y based on t h e t o t a l number o f seeds a c t u a l l y t r a p p e d 138 4.6 A comparison o f seed r a i n s t u d i e s i n f o r e s t e d e n v i r o n m e n t s . 148 5.1 Number o f p l o t s (out o f 30), i m m e d i a t e l y a d j a c e n t t o t h e s c a r i f i e d p l o t s , i n which a p o t e n t i a l l y v e g e t a t i v e l y r e -e s t a b l i s h i n g s p e c i e s o c c u r r e d , a t each s t u d y s i t e 160 5.2 Number o f germ i n a n t s o f n a t i v e and n a t u r a l i z e d s p e c i e s emerging from t h e 30 s c a r i f i e d p l o t seed bank samples c o l l e c t e d a t each s t u d y s i t e 162 5.3 Number o f seeds p e r square meter - s t a n d a r d e r r o r f o r s e l e c t e d i m p o r t a n t s p e c i e s i n t h e s c a r i f i e d p l o t seed bank samples. . 163 5.4 Mean number o f d i s p e r s e d seeds t r a p p e d p e r square meter p e r year - s t a n d a r d e r r o r , f o r s e l e c t e d n a t i v e s p e c i e s , on t h e r i g h t s - o f - w a y a t t h e two st u d y s i t e s 165 5.5 Number o f s c a r i f i e d p l o t s w i t h v e g e t a t i v e l y p e r s i s t i n g o r i n v a d i n g s h o o t s (as d e t e r m i n e d by s i z e and v i g o r o f growth) 167 5.6 Number o f s c a r i f i e d p l o t s w i t h s e e d l i n g s (as d e t e r m i n e d by s i z e and/or t h e pr e s e n c e o f c o t y l e d o n s ) a t t h e two s t u d y s i t e s 171 5.7 T o t a l number o f s c a r i f i e d p l o t s i n which germinants were observed, and t h e number o f p l o t s i n which seeds o f t h e s e s p e c i e s were a l s o found i n t h e seed bank o r seed r a i n . . . .174 i x L i s t o f F i g u r e s 1.1 An a r e a which had been seeded t o a mix o f agronomic g r a s s e s and legumes i n September 1982 t o impede r e d a l d e r (Alnus  rubra) e s t a b l i s h m e n t f o l l o w i n g C/D c l e a r i n g i n 1981 12 1.2 A c o n c e p t u a l framework f o r t h e r e s e a r c h conducted f o r t h i s d i s s e r t a t i o n 14 2.1 L o c a t i o n o f t h e Cheekye Loop and M a l a s p i n a s t u d y s i t e s . . . .19 2.2 A e r i a l photographs o f t h e study s i t e s 21 2.3 A diag r a m m a t i c r e p r e s e n t a t i o n o f t h e d i s c r i m i n a n t a n a l y s e s p e r f ormed t o e s t i m a t e t h e r e l a t i o n s h i p s among and between immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s 29 2.4 The sequence o f p r o g r e s s i v e f r a g m e n t a t i o n , u s i n g r e c i p r o c a l a v e r a g i n g (RA) o r d i n a t i o n , o f t h e f o r e s t v e g e t a t i o n d a t a i n t o v e g e t a t i o n u n i t s 31 2.5 A p r i n c i p a l components a n a l y s i s (PCA) o r d i n a t i o n o f t h e means and 95% c o n f i d e n c e e l l i p s e s f o r t h e f o r e s t v e g e t a t i o n u n i t s 37 2.6 The sequence o f p r o g r e s s i v e f r a g m e n t a t i o n , u s i n g r e c i p r o c a l a v e r a g i n g (RA) o r d i n a t i o n , o f t h e s e r a i v e g e t a t i o n d a t a i n t o v e g e t a t i o n u n i t s 39 2.7 A p r i n c i p a l components a n a l y s i s (PCA) o r d i n a t i o n o f t h e means and 95% c o n f i d e n c e e l l i p s e s of t h e s e r a i v e g e t a t i o n u n i t s 44 2.8 V e g e t a t i o n u n i t s a d j a c e n t t o and on t h e Cheekye Loop r i g h t -of-way., see a t t a c h e d 45 2.9 V e g e t a t i o n u n i t s a d j a c e n t t o and on t h e M a l a s p i n a r i g h t - o f -way, see a t t a c h e d 46 2.10 S c a t t e r diagram o f immature f o r e s t p l o t s on t h e axes r e s u l t i n g from c a n o n i c a l c o r r e l a t i o n a n a l y s i s 51 2.11 S c a t t e r diagram o f e a r l y s e r a i p l o t s on t h e axes r e s u l t i n g from c a n o n i c a l c o r r e l a t i o n a n a l y s i s 55 2.12 A p r o j e c t i o n o f t h e means and 95% c o n f i d e n c e spheres o f t h e immature f o r e s t v e g e t a t i o n u n i t s on t h e f i r s t 3 d i s c r i m i n a n t axes 60 2.13 A p r o j e c t i o n o f t h e means and 95% c o n f i d e n c e spheres o f t h e e a r l y s e r a i v e g e t a t i o n u n i t s on t h e f i r s t 3 d i s c r i m i n a n t axes 63 X 2.14 The r e l a t i o n s h i p between m i n e r a l s o i l exposure and t h e f r e q u e n c y and c o v e r o f r e d a l d e r (mean s i g n i f i c a n c e ) and seeded g r a s s e s (% cover) on t h e t r a n s m i s s i o n l i n e r i g h t s - o f -way 70 2.15 A p r o j e c t i o n o f t h e 95% c o n f i d e n c e spheres o f immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s on t h e f i r s t t h r e e d i s c r i m i n a n t axes 73 3.1 The seed bank g e r m i n a t i o n regimes 83 3.2 Mean and s t a n d a r d e r r o r o f back t r a n s f o r m e d g e r m i n a t i o n d a t a under each depth X s u b s t r a t e t r e a t m e n t c o m b i n a t i o n f o r each s p e c i e s 107 3.3 Mean and s t a n d a r d e r r o r o f b a c k - t r a n s f o r m e d g e r m i n a t i o n d a t a under each shade X water X s u b s t r a t e t r e a t m e n t c o m b i n a t i o n f o r each s p e c i e s I l l 4.1 A sc h e m a t i c diagram o f t h e arrangement o f seed t r a p s i n t h e f o r e s t s and on t h e r i g h t s - o f - w a y 129 4.2 The monthly d i s p e r s a l r a t e s o f s e l e c t e d s p e c i e s , e x p r e s s e d as t h e p e r c e n t o f t h e two-year t o t a l 140 4.3 Number o f seeds t r a p p e d p e r square meter as a f u n c t i o n o f t r a p p i n g s t a t i o n 143 5.1 A sc h e m a t i c diagram o f t h e arrangement o f v e g e t a t i o n p l o t s , seed t r a p s , and s c a r i f i e d p l o t s e s t a b l i s h e d on t h e r i g h t s -of-way 157 5.2 Examples o f t h e s c a r i f i e d p l o t s (foreground) w i t h a d j a c e n t seed t r a p s 158 5.3 Response o f r e s p r o u t i n g s p e c i e s t o p l o t s c a r i f i c a t i o n . .. .168 5.4 F r e q u e n c i e s o f s e e d l i n g s i n s c a r i f i e d p l o t s , and seeds i n t h e seed bank and seed r a i n 172 5.5 Monthly summer p r e c i p i t a t i o n a t t h e two st u d y s i t e s d u r i n g t h e y e a r s i n which s e e d l i n g e s t a b l i s h m e n t i n t h e s c a r i f i e d p l o t s was a s s e s s e d 177 Acknowledgements x i I would l i k e t o thank my a d v i s o r , Dr. M.C. F e l l e r , f o r h i s su p p o r t t h r o u g h o u t t h i s s t u d y : t h e r e s e a r c h and d i s s e r t a t i o n b e n e f i t t e d from h i s a d v i c e . My committee, D r s . K. K l i n k a , L.M. L a v k u l i c h , J.V. T h i r g o o d , and R. T u r k i n g t o n , gave me encouragement, and guidance i n t h e i r r e s p e c t i v e f i e l d s o f e x p e r t i s e . B.C. Hydro and Power A u t h o r i t y p r o v i d e d f i n a n c i a l s u p p o r t f o r f i e l d work, and i n f o r m a t i o n on t h e t r e a t m e n t h i s t o r i e s o f t h e st u d y s i t e s . Members o f t h e P e s t Management Group (R. Roddick, A. M i l l e r , and N. M c l l v e e n ) p r o v i d e d a s s i s t a n c e and s u p p o r t e d t h e r e s e a r c h . M. E v e r e t t , Photogrammetry Systems s u p e r v i s o r , gave me ac c e s s t o a e r i a l photographs o f t h e s i t e s . S e v e r a l f i e l d p e r s o n n e l a s s i s t e d me when I was s e l e c t i n g s t u d y s i t e s . I would l i k e t o thank B. MacLeod f o r h i s a s s i s t a n c e d u r i n g t h e f i r s t y e a r o f t h i s r e s e a r c h : he t a u g h t me a g r e a t d e a l , and gave me much about which t o t h i n k and l a u g h . B. B l a c k w e l l was my f i e l d a s s i s t a n t i n subsequent y e a r s . P l a n t S c i e n c e s Greenhouse p e r s o n n e l C. R o b e r t s , S. Trehearne, and D. Armstrong gave me a s s i s t a n c e and an o c c a s i o n a l cuppa, b o t h o f which were a p p r e c i a t e d . W. Kurz p r o v i d e d f i e l d a s s i s t a n c e and i n v a l u a b l e computer s u p p o r t , and gave me f r i e n d s h i p i n t h e f u l l e s t sense o f the word. Other g r a d u a t e s t u d e n t s a s s i s t e d me i n t h e f i e l d , and gave me a d v i c e about d a t a a n a l y s i s . To t h e many who have, in d e e d , been f r i e n d s i n deed, thank you. 1 Chapter 1 G e n e r a l I n t r o d u c t i o n 1.1 V e g e t a t i o n management The b a c k l o g o f Not S u f f i c i e n t l y R e s t o c k e d (NSR) f o r e s t l a n d i n B r i t i s h Columbia has i n c r e a s e d a t an average of 59,000 h e c t a r e s p e r y e a r d u r i n g t h e l a s t 5 y e a r s (Pearse e t a l . 1985). Concern about t h e i n c r e a s e i n NSR l a n d has r e s u l t e d i n renewed a t t e n t i o n t o t h e c o n c e p t , development, and r e a l i z a t i o n o f v e g e t a t i o n management o b j e c t i v e s . V e g e t a t i o n management has been d e f i n e d as "the s c i e n c e o f m a n i p u l a t i n g v e g e t a t i o n and t h e m i c r o -environment t o d i r e c t s i t e r e s o u r c e s i n t o p r o d u c i n g t h e v e g e t a t i o n complex d e s i r e d t o meet management o b j e c t i v e s " (Conard 1984). As such, v e g e t a t i o n management p r i o r i t i e s w i l l i n f l u e n c e d e c i s i o n s about t h e c h o i c e o f h a r v e s t system and s i t e p r e p a r a t i o n , t h e method of r e g e n e r a t i o n , and a p p r o p r i a t e methods of c o n t r o l l i n g u n d e s i r e d v e g e t a t i o n . To meet v e g e t a t i o n management o b j e c t i v e s e f f e c t i v e l y , s p e c i e s and s i t e r e sponses t o s i l v i c u l t u r a l t r e a t m e n t s must be known. Conard (1984), i n a problem a n a l y s i s o f v e g e t a t i o n management r e s e a r c h needs i n B r i t i s h Columbia, i d e n t i f i e d t e n a r e a s o f r e s e a r c h which she b e l i e v e d s h o u l d r e c e i v e immediate a t t e n t i o n . The s u c c e s s f u l e s t a b l i s h m e n t and o p t i m a l growth of c r o p were emphasized. Three of t h e s e r e s e a r c h p r i o r i t i e s form t h e framework on which t h e o t h e r s are based: t h e s e c o r e p r i o r i t i e s a re d i s c u s s e d below. 2 (1) S t u d i e s o f t h e a u t e c o l o g y o f major c o m p e t i t o r s . F a m i l i a r i t y w i t h t h e growth p a t t e r n s , r e p r o d u c t i v e s t r a t e g i e s , and p h y s i o l o g y o f i m p o r t a n t s p e c i e s , b o t h d e s i r e d and u n d e s i r e d , i s r e q u i r e d f o r e f f i c i e n t and s u c c e s s f u l management o f v e g e t a t i o n . In response t o Conard's recommendation, H a e u s s l e r and Coates (1986) have c o m p i l e d a l l a v a i l a b l e a u t e c o l o g i c a l i n f o r m a t i o n on s e l e c t e d s p e c i e s which a r e i m p o r t a n t c o m p e t i t o r s o f c o n i f e r s i n B r i t i s h Columbia. They i n c l u d e i n f o r m a t i o n on s p e c i e s d i s t r i b u t i o n and abundance, h a b i t a t , growth and development, r e p r o d u c t i o n , e f f e c t s on c r o p t r e e s , and res p o n s e s t o d i s t u r b a n c e o r management i n t h e i r l i t e r a t u r e r e v i e w . H a e u s s l e r and Coates p o i n t out t h a t b a s i c i n f o r m a t i o n i s s t i l l r e q u i r e d f o r some s p e c i e s , however, and t h a t f u r t h e r s t u d i e s o f a l l s p e c i e s a r e w a r r a n t e d . (2) I n v e s t i g a t i o n o f t h e e f f e c t s of h a r v e s t and s i t e p r e p a r a t i o n on r e g e n e r a t i o n . H a r v e s t and s i t e p r e p a r a t i o n can have s i g n i f i c a n t i m p a c t s on t h e c o m p o s i t i o n and v i g o r o f t h e p l a n t communities which d e v e l o p a f t e r t h e s e d i s t u r b a n c e s . These a c t i v i t i e s i n f l u e n c e t h e r e c r u i t m e n t i n t o , and t h e e s t a b l i s h m e n t and growth o f , t h e new p l a n t community by a f f e c t i n g t h e c o m p o s i t i o n and abundance o f r e s i d u a l v e g e t a t i o n , t h e m i c r o -c l i m a t e and n u t r i e n t s t a t u s o f t h e s i t e , and c h a r a c t e r i s t i c s o f th e seedbed. (3) The development o f a system f o r c l a s s i f y i n g and p r e d i c t i n g s e r a i v e g e t a t i o n . Most v e g e t a t i o n management o p e r a t i o n s a re conducted i n t h e e a r l y s t a g e s o f p l a n t s u c c e s s i o n , d u r i n g t h e y e a r s f o l l o w i n g s t a n d h a r v e s t and s i t e p r e p a r a t i o n . 3 An u n d e r s t a n d i n g o f t h e r e l a t i o n s h i p between p r e - and p o s t -d i s t u r b a n c e p l a n t community c o m p o s i t i o n and knowledge o f p a t t e r n s o f s u c c e s s i o n i n d i f f e r e n t p l a n t communities w i l l p e r m i t t h e a p p l i c a t i o n o f a p p r o p r i a t e h a r v e s t and p r e p a r a t i o n methods. Ano t h e r r e s e a r c h p r i o r i t y r e c o g n i z e d by Conard i s t h e development o f o p e r a t i o n a l l y f e a s i b l e methods f o r a s s e s s i n g and p r e d i c t i n g t h e d e n s i t y o f competing v e g e t a t i o n . T h i s r e q u i r e s t h a t i n f o r m a t i o n about s p e c i e s a u t e c o l o g y , i n s i g h t s g a i n e d from s t u d i e s o f t h e e f f e c t s o f d i s t u r b a n c e on community development, and s e r a i community c l a s s i f i c a t i o n be combined. 1.2 V e g e t a t i o n management on t r a n s m i s s i o n l i n e r i g h t s - o f - w a y Conard (1984) r e c o g n i z e d s e v e r a l major v e g e t a t i o n complexes which compete w i t h c o n i f e r c r o p s i n B r i t i s h Columbia. Those which a r e o f p a r t i c u l a r i mportance i n c o a s t a l B.C. are l i s t e d i n Tab l e 1.1. An u n d e r s t a n d i n g o f t h e a u t e c o l o g y o f t h e s p e c i e s i n t h e s e v e g e t a t i o n complexes, t h e response o f t h e s e complexes and t h e i r component s p e c i e s t o d i s t u r b a n c e , and t h e i n t e r -r e l a t i o n s h i p s among t h e s p e c i e s , w i l l c o n t r i b u t e t o t h e b e t t e r management o f t h e f o r e s t r e s o u r c e . Management f o r t i m b e r p r o d u c t i o n i s not t h e o n l y c o n t e x t i n which t h i s i n f o r m a t i o n i s r e l e v a n t , however. Many o f t h e s p e c i e s l i s t e d i n Table 1.1 a r e a l s o i m p o r t a n t members of p l a n t communities on t r a n s m i s s i o n l i n e r i g h t s - o f - w a y i n B r i t i s h Columbia. The s p e c i f i c o b j e c t i v e s and t a r g e t s p e c i e s o f t r a n s m i s s i o n l i n e r i g h t - o f - w a y v e g e t a t i o n management d i f f e r from t h o s e o f 4 Table 1.1 Major complexes o f p o t e n t i a l competing v e g e t a t i o n i n c o a s t a l B r i t i s h Columbia. M o d i f i e d from Conard (1984). P o t e n t i a l vegetation "problems" T y p i c a l species Biogeoclimatic u n i t s (coastal)' I. Tree dominated Red alder Red alder (Alnus rubra) CWH, CDF, CCPH Red alder with shrub understory Red alder, thimbleberry (Rubus p a r v i f l o r u s ) , salmonberry (R. s p e c t a b i l i s ) , s t i n k currant (Ribes bracteosum), sword fern (Polvstichum munitum), vine maple (Acer circinatum) CWH, CDF, CCPH Cottonwood Black cottonwood (Populus t r i c h o c a r p a ) , red-osier dogwood (Cornus s e r i c e a ) , red elderberry (Sambucus racemosa), thimbleberry CWH B i g l e a f maple B i g l e a f maple (Acer macrophyllum) CDF, CWH I I . Shrub dominated Salmonberry/ thimbleberry Salmonberry, thimbleberry, s t i n k currant, vine maple CWH, CCPH S a l a l S a l a l (Gaultheria s h a l l o n ) , bracken fern (Pteridium aouilinum), fireweed (Epilobium anqustlfolium) CDF, CWH, CCPH * CWH = C o a s t a l Western Hemlock; CDF = C o a s t a l D o u g l a s - f i r ; CCPH = C o a s t a l Cedars-Pine-Hemlock 5 c o n i f e r o u s f o r e s t management. Both are concerned w i t h c o n t r o l l i n g t h e growth of d e c i d u o u s t r e e s p e c i e s , but many shrub s p e c i e s which are c o n s i d e r e d weeds i n t h e c o n t e x t o f t i m b e r p r o d u c t i o n a r e i d e a l as r i g h t - o f - w a y c o v e r because o f t h e i r s m a l l s t a t u r e and t h e i r a b i l i t y t o i n t e r f e r e w i t h t h e e s t a b l i s h m e n t o f t r e e s p e c i e s . 1.2.1 G e n e r a l c o n c e p t s and c o n s i d e r a t i o n s R i g h t - o f - w a y management i s c o n s i d e r e d t o be one o f t h e p r i m a r y e n v i r o n m e n t a l i s s u e s f a c i n g u t i l i t y companies (Shepard 1987). R i g h t - o f - w a y v e g e t a t i o n management has been d e f i n e d as t h e " a p p l i e d s c i e n c e , or p r a c t i c a l a r t , o f managing v e g e t a t i o n a t t h e l o w e s t l o n g t e r m c o s t s w i t h t h e h i g h e s t c o n s e r v a t i o n , r e s o u r c e , s o c i a l , and s c e n i c v a l u e s which are c o n s i s t e n t w i t h t h e e n g i n e e r i n g needs" ( E g l e r and F oote 1975). E l e c t r i c u t i l i t y companies must m a i n t a i n t h e i r r i g h t s - o f - w a y f r e e o f t h o s e s p e c i e s which a r e c a p a b l e o f g rowing i n t o h i g h - t e n s i o n t r a n s m i s s i o n l i n e s and t h u s i n t e r f e r i n g w i t h r e l i a b l e power t r a n s m i s s i o n , t h o s e w hich b l o c k a c c e s s roads and i n so d o i n g h i n d e r l i n e maintenance, t h o s e which p r e s e n t a f i r e h a z a r d , and t h o s e which a r e i n c o n f l i c t w i t h t h e d e s i g n a t e d secondary use o f t h e r i g h t - o f - w a y (e.g. range o r a g r i c u l t u r e ) . V e g e t a t i o n c l e a r i n g and management ar e o f t e n t r e a t e d as two v e r y d i s t i n c t , u n r e l a t e d s t a g e s i n r i g h t - o f - w a y development, and are o f t e n s u p e r v i s e d by two d i f f e r e n t departments w i t h i n a power company. However, E g l e r and F oote (1975), i n a book e n t i t l e d The  P l i g h t o f t h e R i g h t o f w a y Domain: V i c t i m o f V a n d a l i s m , urge t h a t 6 t h e s e two s t a g e s not be c o n s i d e r e d s e p a r a t e l y . They d e f i n e t h e f i r s t s t a g e i n t h e development o f a t r a n s m i s s i o n l i n e r i g h t - o f -way as " v e g e t a t i o n c o n s t r u c t i o n " : m o d i f i c a t i o n , not c l e a r i n g , o f th e e x i s t i n g v e g e t a t i o n s h o u l d be t h e o b j e c t i v e . Among what E g l e r and Foote c a l l t h e " S i x I l l u s t r i o u s Don'ts" o f r i g h t - o f - w a y c o n s t r u c t i o n , two a r e p e r t i n e n t t o t h i s f i r s t s t a g e o f r i g h t - o f -way development, and echo Conard's (1984) emphasis on t h e impact o f h a r v e s t i n g system and s i t e p r e p a r a t i o n : (1) don't c l e a r c u t th e l a n d , and (2) don't s c a r i f y t h e s o i l . E g l e r and Foote i d e n t i f y t h e second s t a g e i n t h e development o f a t r a n s m i s s i o n l i n e r i g h t - o f - w a y as v e g e t a t i o n maintenance, and emphasize t h a t t h e r e q u i r e m e n t s o f t h i s s t a g e w i l l depend upon how t h e f i r s t s t a g e was c a r r i e d o u t . H e r b i c i d e s a r e o f t e n used as a t o o l i n t r a n s m i s s i o n l i n e r i g h t - o f - w a y v e g e t a t i o n management ( C a r v e l l 1976; Bramble e t a l . 1984; D r e y e r and N i e r i n g 1986). Bramble and Byrnes (1974, 1976, 1983) found t h a t h e r b i c i d a l m a n i p u l a t i o n o f v e g e t a t i o n may c r e a t e p l a n t assemblages which r e s i s t t h e i n v a s i o n o f t r e e s . They found t h a t s i n g l e - s p e c i e s s t a n d s were more e f f e c t i v e a t r e s i s t i n g t r e e i n v a s i o n t h a n mixed s p e c i e s s t a n d s . Other a u t h o r s r e p o r t s i m i l a r r e s u l t s from m e c h a n i c a l c l e a r i n g o p e r a t i o n s : Pound and E g l e r (1953) d e s c r i b e low, dense shrub f o r m a t i o n s which had l e s s t h a n 1% t r e e c o v e r 15 y e a r s a f t e r c l e a r i n g due t o t h e " a c c i d e n t a l absence o f s u i t a b l e c o n d i t i o n s f o r g e r m i n a t i o n and development o f t r e e s , and t h e absence o f r o o t - s u c k e r i n g s p e c i e s . " Agronomic g r a s s e s and legumes, o f t e n seeded i n o r d e r t o c o n t r o l s o i l e r o s i o n a l o n g f o r e s t roads and r i g h t s - o f - w a y ( L e i t h 7 1974; Dyrness 1975; K r a e g e r 1976; C a r r 1980; M c C o n n e l l 1982), are a l s o used t o impede t h e e s t a b l i s h m e n t o f unwanted t r e e s and b r u s h on r i g h t s - o f - w a y . Combined w i t h d i s k i n g o r h a r r o w i n g , b o t h o f which may k i l l many of t h e v e g e t a t i v e p r o p a g u l e s not removed d u r i n g t h e c l e a r i n g o f t r e e s , g r a s s s e e d i n g has been used s u c c e s s f u l l y t o reduce t h e number of t r e e and b r u s h r e s p r o u t s and s e e d l i n g s ( L e i t h 1974; A l l s b r o o k s e t a l . 1984). Some g r a s s l a n d communities are s u b j e c t t o i n v a s i o n by t r e e s and s h r u b s , however, and can o n l y be m a i n t a i n e d by h e r b i c i d e s ( E g l e r and Foote 1975; C a r v e l l and J o h n s t o n 1978) . F u r t h e r m o r e , i f i n f e r t i l e s u b s o i l s ar e exposed d u r i n g c l e a r i n g , seeded g r a s s e s and legumes may r e q u i r e r e g u l a r f e r t i l i z a t i o n t o m a i n t a i n t h e i r e f f e c t i v e n e s s (Dyrness 1975). The mechanisms by which h e r b i c i d e - i n d u c e d p l a n t assemblages, seeded agronomic s p e c i e s , and some spontaneous communities ( N i e r i n g and E g l e r 1955; N i e r i n g and Goodwin 1974; E g l e r and Foote 1975) r e s i s t t r e e i n v a s i o n may be examples o f t h e " i n h i b i t i o n pathway" of s u c c e s s i o n ( C o n n e l l and S l a t y e r 1977), i n which an e s t a b l i s h e d community e f f e c t i v e l y i n t e r f e r e s w i t h t h e r e g e n e r a t i o n o f o t h e r s p e c i e s . T h i s may be t h e r e s u l t o f c o m p e t i t i o n f o r l i g h t , water, or n u t r i e n t r e s o u r c e s (Taber and West 1984; T i l m a n 1985), a l l e l o p a t h y (Del M o r a l and Cates 1971; T i l l m a n 1984), o r p h y s i c a l i n t e r f e r e n c e , as when l o d g e d g r a s s stems p r e v e n t d i s p e r s e d seeds from coming i n t o c o n t a c t w i t h t h e s o i l ( R a b i n o w i t z and Rapp 1980). The t r a d i t i o n a l methods of managing v e g e t a t i o n ( h e r b i c i d e s , m e c h a n i c a l , manual) are r e c o g n i z e d as b e i n g c o r r e c t i v e , t h a t i s , 8 t h e y k i l l o r i n h i b i t e s t a b l i s h e d p l a n t s o f t h e t a r g e t s p e c i e s ( B o n n e v i l l e Power A d m i n i s t r a t i o n 1982). In c o n t r a s t / b i o l o g i c a l methods, such as t h e p l a n t i n g o r e n c o u r a g i n g o f low-growing s p e c i e s , a r e p r e v e n t a t i v e i n t h a t t h e y i n h i b i t t h e g e r m i n a t i o n o r e s t a b l i s h m e n t o f t h e unwanted s p e c i e s ( B o n n e v i l l e Power A d m i n i s t r a t i o n 1982). I d e a l l y , s t a b l e , s e l f - m a i n t a i n i n g p l a n t communities, where t r e e i n v a s i o n i s slow t o i n s i g n i f i c a n t and e a s i l y c o n t r o l l e d , s h o u l d be d e v e l o p e d on t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . I f , however, a s i t e has been c l e a r e d t o m i n e r a l s o i l , t h e c a p a c i t y o f n a t i v e s p e c i e s t o form a s t a b l e , s e l f - m a i n t a i n i n g community i s r e t a r d e d ( E g l e r and Foote 1975; C a r v e l l and J o h n s t o n 1978). I f i n s u f f i c i e n t a t t e n t i o n i s g i v e n t o t h e r a m i f i c a t i o n s o f r i g h t - o f -way c l e a r i n g , subsequent v e g e t a t i o n management p r a c t i c e s w i l l emphasize c o r r e c t i v e methods, and may be c o s t l y and o n l y p a r t i a l l y s u c c e s s f u l . 1.2.2 V e g e t a t i o n management on t r a n s m i s s i o n l i n e r i g h t s - o f -way i n B r i t i s h Columbia B r i t i s h Columbia Hydro and Power A u t h o r i t y t r a n s m i s s i o n l i n e r i g h t s - o f - w a y e x t e n d over a p p r o x i m a t e l y 59,200 km, almost 85% o f which l i e i n f o r e s t e d r e g i o n s (B.C. Hydro 1986). In t h e s e a r e a s t h e p r i m a r y v e g e t a t i o n management o b j e c t i v e i s t h e c o n t r o l o f s e r a i s p e c i e s such as r e d a l d e r (Alnus r u b r a ) , b i g l e a f maple (Acer macrophyllum ), b l a c k Cottonwood (Populus t r i c h o c a r p a ) , paper b i r c h ( B e t u l a p a p y r i f e r a ) , and t r e m b l i n g aspen (Populus  t r e m u l o i d e s ) , a l l o f which can t h r e a t e n r e l i a b l e power 9 t r a n s m i s s i o n because of t h e i r a b i l i t y t o grow i n t o c o n t a c t w i t h t h e t r a n s m i s s i o n l i n e s , t h e r e b y s h o r t - c i r c u i t i n g t h e e l e c t r i c a l c o n d u c t o r s and c a u s i n g power outages ( M i l l e r 1982). B.C. Hydro and Power A u t h o r i t y has d e f i n e d f o u r s t a n d a r d s (Table 1.2) f o r c l e a r i n g f o r e s t e d l a n d p r i o r t o t r a n s m i s s i o n l i n e c o n s t r u c t i o n . These s t a n d a r d s a r e d i f f e r e n t i a t e d on t h e b a s i s o f t h e t y p e o f equipment used t o remove f e l l e d m a t e r i a l s from t h e s i t e , whether non-timber s p e c i e s a r e c u t , t h e c r i t e r i a f o r removal o f l o g g i n g d e b r i s and stumps, f u r t h e r t e r r a i n t r e a t m e n t p r e s c r i p t i o n s , and t h e t y p e o f t e r r a i n where the s t a n d a r d i s a p p l i e d . The v e g e t a t i o n problems which f a c e B.C. Hydro's P e s t Management Group f i n d t h e i r s o u r c e i n t h e f a c t t h a t , i n t h e p a s t , r i g h t - o f - w a y c l e a r i n g s t a n d a r d s were p r e s c r i b e d by t h e E n g i n e e r i n g S e c t i o n (Roddick, 1986, p e r s o n a l c ommunication). The p r i o r i t i e s o f t h e E n g i n e e r i n g S e c t i o n were t o ensure t h a t a l l p o t e n t i a l danger t r e e s which c o u l d f a l l on t h e t r a n s m i s s i o n l i n e were removed, and t h a t tower c o n s t r u c t i o n and l i n e s t r i n g i n g be as u n c o m p l i c a t e d as p o s s i b l e . The p r i m a r y e n v i r o n m e n t a l c o n c e r n was s o i l e r o s i o n , i n t h a t i t c o u l d a f f e c t t h e s t a b i l i t y o f tower s i t e s , and c o u l d have n e g a t i v e i m p a c t s on water q u a l i t y and f i s h h a b i t a t . S t a n d a r d C o r D c l e a r i n g p r o c e d u r e s were sometimes a s s i g n e d where A or B would have been more a p p r o p r i a t e . L i t t l e o r no c o n s i d e r a t i o n was g i v e n t o t h e v e g e t a t i o n t h a t was b e i n g c u t . F u r t h e r m o r e , c l e a r i n g c o n t r a c t o r s were g i v e n some f l e x i b i l i t y i n Table 1.2 B r i t i s h Columbia Hydro and Power Authority c l e a r i n g standards. Modified from M i l l e r 1982 and B.C. Hydro 1980. C l e a r i n g standard Equipment used to remove logs from s i t e Vegetation cut Treatment of d e b r i s and waste material Further treatment Terra i n where a p p l i e d A Rubber-tired skidder or grapple loader, or cable-yarder S e l e c t i v e : compatible species r e t a i n e d Debris over 15cm diameter l e f t f l a t on ground, i f smaller, removed or burned None Near streams and on wet, steep or unstable t e r r a i n B Rubber-tired skidder or grapple loader, or cable-yarder S e l e c t i v e Debris removed or burned where debris removal i s required None Se n s i t i v e t e r r a i n c Tracked equipment Clear cut Debris and stumps to 60cm diameter grubbed*, removed or burned Graded, groomed, and seeded to grass Stable ground (for c a t t l e grazing) D Tracked equipment Clear cut Debris and a l l stumps grubbed, and removed or burned Graded, groomed, seeded to grass or c u l t i v a t e d Stable ground (for range or other a g r i c u l t u r a l uses) * Grubbing i s "the complete removal, by machinery, of roots, stumps, and other forest debris from the surface of the right-of-way" (B.C. Hydro 1980). 11 e x e c u t i n g t h e c l e a r i n g s t a n d a r d s which had been p r e s c r i b e d by t h e E n g i n e e r i n g S e c t i o n . C o n t r a c t o r s o f t e n found i t more e c o n o m i c a l t o c a r r y out a b l a n k e t c l e a r c u t ( s t a n d a r d C o r D) t h a n t h e s e l e c t i v e c u t ( s t a n d a r d A or B) t h a t had been recommended. C l e a r i n g s t a n d a r d s C and D v i o l a t e E g l e r and F o o t e ' s (1975) i n j u n c t i o n s a g a i n s t c l e a r c u t t i n g and s c a r i f i c a t i o n . By k i l l i n g most o f t h e endemic v e g e t a t i o n , t h e p o t e n t i a l o f endemic p o p u l a t i o n s o f t h o s e s p e c i e s which a r e c o m p a t i b l e w i t h r i g h t - o f -way h e i g h t r e s t r i c t i o n s t o expand and occupy a s i t e i s d i m i n i s h e d and t h e o p p o r t u n i t y f o r i n v a s i o n by unwanted s p e c i e s i s i n c r e a s e d . A l t h o u g h t h e s e v e r e l y d i s t u r b e d a r e a s are o f t e n seeded w i t h a mix o f agronomic g r a s s e s and legumes i n o r d e r t o impede t h e e s t a b l i s h m e n t o f t r e e s e e d l i n g s , s p e c i e s such as r e d a l d e r (Alnus rubra) o f t e n a r e a b l e t o invade ( F i g u r e 1.1). 1.3 O b j e c t i v e s o f t h i s s t u d y Fundamental t o e f f e c t i v e v e g e t a t i o n management i n any c o n t e x t i s an u n d e r s t a n d i n g o f t h e response of components o f t h e f l o r a t o t h e v a r i o u s t e c h n i q u e s and p r o c e d u r e s employed i n h a r v e s t i n g and/or management. The c u r r e n t u n d e r s t a n d i n g o f s u c c e s s i o n f o l l o w i n g t h e c l e a r i n g o f f o r e s t e d l a n d i s i n a d e q u a t e , however, and c o n s e q u e n t l y h a r v e s t i n g and r i g h t - o f - w a y c l e a r i n g may r e s u l t i n u n f o r e s e e n or u n i n t e n d e d problems. To improve t h i s u n d e r s t a n d i n g , s e v e r a l q u e s t i o n s must be answered. These q u e s t i o n s p a r a l l e l Conard's (1984) r e s e a r c h p r i o r i t i e s , but are e x p r e s s e d here w i t h o u t r e f e r e n c e t o a c r o p 12 a) b) Figure 1.1 An area which had been seeded t o a mix of agronomic grasses and legumes i n September 1982 to impede red a l d e r (Alnus rubra) establishment f o l l o w i n g C/D c l e a r i n g i n 1981. a) 1983; b) 1986. 13 s p e c i e s . (1) What p l a n t communities a r i s e f o l l o w i n g d i f f e r e n t c l e a r i n g i n t e n s i t i e s ? (2) Can f o r e s t s i t e s be c l a s s i f i e d i n o r d e r t o p r e d i c t s u c c e s s i o n a l community s p e c i e s c o m p o s i t i o n o r t r e n d s i n s u c c e s s i o n a l development? (3) What are t h e r e l a t i v e c o n t r i b u t i o n s o f r e s p r o u t i n g o r r e s i d u a l v e g e t a t i o n , v i a b l e seeds s t o r e d i n t h e s o i l , and d i s p e r s e d seeds t o r e c r u i t m e n t i n t o t h e s e r a i p l a n t community? (4) How do i n d i v i d u a l s p e c i e s respond t o d i s t u r b a n c e i n terms o f r e c o v e r y and/or r e i n v a s i o n ? Answers t o t h e s e q u e s t i o n s a re complex and i n t e r - r e l a t e d . The g e n e r a l o b j e c t i v e o f t h e r e s e a r c h r e p o r t e d here was t o e v a l u a t e t h e response o f c o a s t a l B r i t i s h Columbia f o r e s t p l a n t s p e c i e s t o r i g h t - o f - w a y c l e a r i n g p r o c e d u r e s . F a c t o r s which c o n t r i b u t e t o t h e c o u r s e o f p l a n t s u c c e s s i o n (as shown i n F i g u r e 1.2) were i n v e s t i g a t e d . S e r a i v e g e t a t i o n which d e v e l o p s f o l l o w i n g d i s t u r b a n c e (management) a r i s e s , i n p a r t , from t h e v e g e t a t i o n which s u r v i v e s t h e d i s t u r b a n c e . The s e r a i v e g e t a t i o n w i l l a l s o be i n f l u e n c e d by t h e r e m a i n i n g b u r i e d v i a b l e seeds and d i s p e r s e d seeds, b o t h o f which w i l l be a f f e c t e d by t h e d i s t u r b a n c e . These f a c t o r s w i l l be c o n s i d e r e d i n g r e a t e r d e t a i l i n t h e subsequent c h a p t e r s o f t h i s t h e s i s . Each c h a p t e r i s i n t e n d e d t o be complete w i t h i n i t s e l f , as w e l l as a s e p a r a t e p u b l i c a t i o n . C o n s e q u e n t l y , t h e r e i s some d u p l i c a t i o n between c h a p t e r s . A n a l y s i s , c l a s s i f i c a t i o n , and mapping o f t h e v e g e t a t i o n on two r i g h t s - o f - w a y and t h e f o r e s t s a d j a c e n t t o them (Chapter 2) a l l o w e d t h e comparison o f s p e c i e s r esponses t o d i f f e r e n t c l e a r i n g s t a n d a r d s . E s t i m a t e s o f t h e d i s t r i b u t i o n o f t h e r e s e r v e o f 14 VEGETATION + BURIED SEEDS (Bud bank) (Seed bank) (2,5) (3,5) DISTURBANCE (TYPE, INTENSITY) (Management impact) (2,5) RESIDUAL VEGETATION (5) t RESIDUAL SEED BANK (3) DISPERSED SEEDS (Seed rain) (4,5) L J t SERAL VEGETATION (2,5) Figure 1.2 A conceptual framework for the research conducted for t h i s d i s s e r t a t i o n . Numbers i n parentheses re f e r to the chapter(s) i n which the subject i s addressed. 15 v i a b l e seeds and o t h e r p r o p a g u l e s s t o r e d i n t h e f o r e s t f l o o r and m i n e r a l s o i l (Chapter 3) p r o v i d e d a t a on p o t e n t i a l s e e d l i n g r e c r u i t m e n t a f t e r c l e a r i n g , as a f u n c t i o n o f t h e depth o f s o i l d i s t u r b a n c e . Greenhouse t r i a l s e x a m i n i n g t h e g e r m i n a t i o n b e h a v i o r o f s e l e c t e d s p e c i e s were a l s o conducted. Data on t h e seed r a i n r e c e i v e d by t h e r i g h t s - o f - w a y over a two y e a r p e r i o d (Chapter 4) p r o v i d e i n f o r m a t i o n about s e a s o n a l and s p a t i a l p a t t e r n s o f seed d i s p e r s a l . F i n a l l y , s e e d l i n g g e r m i n a t i o n and e s t a b l i s h m e n t , and v e g e t a t i v e r e c o v e r y on s c a r i f i e d p l o t s were q u a n t i f i e d (Chapter 5 ) : t h e u t i l i t y o f bud bank, seed bank, and seed r a i n d a t a f o r p r e d i c t i n g e a r l y s e r a i p l a n t community s p e c i e s c o m p o s i t i o n on t h e s e s i t e s i s d i s c u s s e d . 16 C h apter 2 P l a n t Community C o m p o s i t i o n and V e g e t a t i o n - E n v i r o n m e n t R e l a t i o n s h i p s 2.1 I n t r o d u c t i o n In B r i t i s h Columbia, i n c r e a s i n g a t t e n t i o n i s b e i n g g i v e n t o th e causes f o r t h e s u c c e s s o r f a i l u r e o f s i l v i c u l t u r a l p r e s c r i p t i o n s on h a r v e s t e d f o r e s t l a n d . I t i s r e c o g n i z e d t h a t an u n d e r s t a n d i n g o f b o t h t h e a u t e c o l o g y o f p l a n t s p e c i e s , and t h e impact s o f management ( h a r v e s t i n g , s l a s h b u r n i n g , s i t e p r e p a r a t i o n , and o t h e r s i l v i c u l t u r a l p r e s c r i p t i o n s ) i . e . d i s t u r b a n c e , on p l a n t community development i s e s s e n t i a l (Conard 1984). V e g e t a t i o n management on t r a n s m i s s i o n l i n e r i g h t s - o f - w a y i n some r e g i o n s o f B.C. i s a s p e c i a l case o f f o r e s t v e g e t a t i o n management. W h i l e t h e u l t i m a t e o b j e c t i v e s of v e g e t a t i o n management on r i g h t - o f - w a y l a n d d i f f e r from t h o s e o f f o r e s t r e g e n e r a t i o n , t h e same i n f o r m a t i o n can h e l p t o a c h i e v e management g o a l s e f f i c i e n t l y and e f f e c t i v e l y i n b o t h c o n t e x t s . The r e l a t i o n s h i p between t h e t y p e and s e v e r i t y o f d i s t u r b a n c e and t h e c o u r s e o f s u c c e s s i o n has been t h e s u b j e c t o f i n t e r e s t and argument f o r decades. The need f o r t h e c h a r a c t e r i z a t i o n o f s e r a i p l a n t communities' i s a l o g i c a l consequence o f b o t h t h e i n t e r e s t i n v e g e t a t i o n - d i s t u r b a n c e r e l a t i o n s h i p s ( P f i s t e r 1982; Conard 1984) and t h e growing p r o p o r t i o n o f t h e f o r e s t l a n d base which comprises s e r a i communities (Arno 1982; K l i n k a e t a l . 1985). Management o f f o r e s t e d l a n d f o c u s e s on t h e m a n i p u l a t i o n o f s e r a i v e g e t a t i o n f o r 17 th e purposes o f r e g e n e r a t i o n , i n t h e case o f f o r e s t r y , o r t r e e s u p p r e s s i o n , i n t h e case o f t r a n s m i s s i o n l i n e r i g h t - o f - w a y management. C l a s s i f i c a t i o n systems, such as t h e b i o g e o c l i m a t i c ecosystem c l a s s i f i c a t i o n system ( P o j a r e t al. 1987) which i s used w i d e l y i n B.C., or t h e f o r e s t h a b i t a t t y p e c l a s s i f i c a t i o n system (Daubenmire 1952; Daubenmire and Daubenmire 1968) t h a t i s used i n th e w e s t e r n U.S., p r o v i d e a framework f o r t h e c o l l e c t i o n o f d a t a (Fosberg 1967). C l a s s i f i c a t i o n systems i n t e g r a t e v e g e t a t i o n and s i t e i n f o r m a t i o n f o r t h e purposes o f i d e n t i f y i n g and c h a r a c t e r i z i n g ecosystems, t h e r e b y o r g a n i z i n g d a t a f o r t h e c l a r i f i c a t i o n o f r e l a t i o n s h i p s w i t h i n and among ecosystems, and a s s i s t i n g i n communication and t h e a p p l i c a t i o n o f knowledge (Fosberg 1967; P f i s t e r 1982; P o j a r e t a l . 1987). T h i s v e g e t a t i o n s t u d y was p a r t o f a l a r g e r r e s e a r c h p r o j e c t which examined d i s t u r b a n c e and i t s impact on t h e c o m p o s i t i o n o f e a r l y s e r a i p l a n t communities. The s p e c i f i c o b j e c t i v e s o f t h e v e g e t a t i o n s t u d y were: (1) t o i d e n t i f y t h e p l a n t communities c h a r a c t e r i s t i c o f t h e immature second growth f o r e s t s a d j a c e n t t o , and t h e e a r l y s e r a i p l a n t communities on, two t r a n s m i s s i o n l i n e r i g h t s - o f - w a y i n c o a s t a l B.C.; (2) t o d e s c r i b e v e g e t a t i o n -environment r e l a t i o n s h i p s f o r t h e immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s ; (3) t o e s t i m a t e t h e i n f l u e n c e o f d i s t u r b a n c e i n d e t e r m i n i n g p l a n t community s p e c i e s c o m p o s i t i o n ; and (4) t o dete r m i n e t h e r e l a t i o n s h i p s between t h e immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s . V e g e t a t i o n and environment d a t a were c o l l e c t e d f o r each sample p l o t . S e v e r a l m u l t i v a r i a t e a n a l y t i c a l t e c h n i q u e s were t h e n a p p l i e d t o t h e d a t a t o de t e r m i n e v e g e t a t i o n 18 p a t t e r n s and t o c l a r i f y r e l a t i o n s h i p s between t h e v e g e t a t i o n and s e l e c t e d e n v i r o n m e n t a l p a r a m e t e r s . 2.2 Methods 2.2.1 The s t u d y s i t e s T r a n s m i s s i o n l i n e r i g h t s - o f - w a y o f s i m i l a r age and v e g e t a t i o n , and w i t h comparable, known management h i s t o r i e s were r e q u i r e d . These c r i t e r i a , and ease of a c c e s s , l i m i t e d t h e number o f a p p r o p r i a t e s i t e s . U l t i m a t e l y , two p o r t i o n s o f t h e Cheekye-Dunsmuir r i g h t - o f - w a y were s e l e c t e d ( F i g u r e 2.1). The Cheekye Loop (49°47' n o r t h , 123°08' west) 500 kV t r a n s m i s s i o n l i n e r i g h t - o f - w a y ( l i n e s 5L42 and 5L45) i s a p p r o x i m a t e l y 10 km n o r t h o f Squamish, B.C., and i s s i t u a t e d i n t h e P a c i f i c Ranges s e c t i o n o f t h e Coast Mountains ( H o l l a n d 1976). I t i s l o c a t e d i n t h e P a c i f i c Ranges D r i e r M a r i t i m e v a r i a n t o f t h e C o a s t a l Western Hemlock b i o g e o c l i m a t i c zone (CWHa2) ( N u s z d o r f e r e t a l . 1985). Mean annual p r e c i p i t a t i o n i n t h e CWHa2 i s 1785 mm, w i t h an average o f 1.6 months of water d e f i c i t ; mean annual t e m p e r a t u r e i s 9.9°C ( K l i n k a e t a l . 1979). The r i g h t - o f - w a y runs e a s t o f t h e Cheekye s u b s t a t i o n , c r o s s e s t h e Cheekye R i v e r and Highway 99, and j o i n s t h e K e l l y Lake t o M e r i d i a n 500 kV t r a n s m i s s i o n l i n e (5L42). The r i g h t - o f -way i s a p p r o x i m a t e l y 200 m wide. Of t h e 60 ha (3.4 km l i n e a r d i s t a n c e ) c l e a r e d f o r t h e Cheekye Loop t r a n s m i s s i o n l i n e , F i g u r e 2.1 L o c a t i o n o f t h e Cheekye Loop and M a l a s p i n a s t u d y s i t e s . 20 a p p r o x i m a t e l y 37 ha (1.8 km l i n e a r d i s t a n c e ) between t h e Cheekye R i v e r and Highway 99 were i n c l u d e d i n t h e s t u d y . The w e s t e r n 11 ha o f t h e s t u d y a r e a i s t h e f l o o d p l a i n o f t h e Cheekye R i v e r ( e l e v a t i o n 90 m), which ends a b r u p t l y as t h e l a n d r i s e s (to a maximum o f 240 m). The r e m a i n i n g 26 ha c o n s i s t p r i m a r i l y o f s h a l l o w , s k e l e t a l s o i l s o v er g r a n i t i c r o c k , w i t h a few l o w e r , wet ar e a s ( F i g u r e 2.2a). The age o f t h e f o r e s t a t t h e tim e o f c l e a r i n g (September 1980 - October 1981), as d e t e r m i n e d by r i n g c o u n t s o f stumps on t h e r i g h t - o f - w a y , was 26 ± 6 y e a r s (22-35, n=7). The M a l a s p i n a (49°40' n o r t h , 124°58' west) 500 kV t r a n s m i s s i o n l i n e r i g h t - o f - w a y ( l i n e s 5L29 and 5L31) i s a p p r o x i m a t e l y 30 km n o r t h w e s t o f S e c h e l t B.C. on t h e S e c h e l t p e n i n s u l a . The s i t e i s s i t u a t e d i n t h e G e o r g i a Lowland s e c t i o n o f t h e C o a s t a l Trough ( H o l l a n d 1976). S o i l s i n t h i s r e g i o n a r e d e r i v e d from s h a l l o w d e p o s i t s o f u n c o n s o l i d a t e d m a t e r i a l s o f g l a c i a l , g l a c i o m a r i n e , marine, o r f l u v i a l o r i g i n , o v e r l y i n g t i l l o r i n t r u s i v e igneous bedrock (McCammon 1977). The s i t e i s l o c a t e d i n t h e t r a n s i t i o n between t h e Wetter M a r i t i m e C o a s t a l D o u g l a s - f i r b i o g e o c l i m a t i c subzone (CDFb) and t h e CWHa2 b i o g e o c l i m a t i c v a r i a n t ( N u s z d o r f e r e t al.. 1985) . Mean annual p r e c i p i t a t i o n o f t h e CDFb i s 1217 mm, w i t h an average of 3.8 months o f water d e f i c i t ; t h e mean annual t e m p e r a t u r e i s 8.8°C ( K l i n k a e t a l . 1979). T h i s s e c t i o n o f t h e Cheekye-Dunsmuir t r a n s m i s s i o n l i n e r i g h t - o f - w a y , which i s a p p r o x i m a t e l y 100 m wide, extends west 21 22 from t h e M a l a s p i n a s u b s t a t i o n and c r o s s e s Highway 101 and Sakinaw Lake. A 7 ha a r e a (0.7 km l i n e a r d i s t a n c e ) , j u s t west of Highway 101, was i n c l u d e d i n t h e s t u d y : most o f t h i s a r e a l i e s between 70 and 100 m i n e l e v a t i o n ( F i g u r e 2.2b). The age o f t h e f o r e s t a t c l e a r i n g ( J u l y 1981 - December 1981) was 39 ± 3 y e a r s (35-42, n = l l ) . H e a v i l y d i s t u r b e d a r e a s o f b o t h s t u d y s i t e s were seeded, a t a r a t e o f a p p r o x i m a t e l y 28 kg/ha, w i t h a mix o f agronomic g r a s s e s and legumes i n o r d e r t o c o n t r o l e r o s i o n and impede th e e s t a b l i s h m e n t o f r e d a l d e r (Alnus r u b r a ) . The seed mix i n c l u d e d F e s t u c a r u b r a (20%, by w e i g h t ) , L o l i u m perenne (3 0 % ) , Phleum  p r a t e n s e ( 1 0 % ) , Poa p r a t e n s i s ( 1 0 % ) , T r i f o l i u m hybridum ( 2 0 % ) , and T r i f o l i u m repens ( 1 0 % ) . A t t h e Cheekye Loop, t h e e n t i r e f l o o d p l a i n , t h e a c c e s s r o a d s , and most of t h e g e n t l y s l o p i n g , m o d e r a t e l y d i s t u r b e d a r e a s were seeded i n September 1982. Almost a l l o f t h e M a l a s p i n a s t u d y s i t e was seeded i n May 1982, and t h e n f e r t i l i z e d ( J u l y 1982: 141 kg/ha 18-18-18 N-P-K p l u s 141 kg/ha s l o w - r e l e a s e s u l f u r - c o a t e d u r e a ) . 2.2.2 F i e l d methods V e g e t a t i o n d a t a were c o l l e c t e d d u r i n g t h e summers of 1983 and 1984, a p p r o x i m a t e l y 3 y e a r s a f t e r t h e r i g h t s - o f - w a y were c l e a r e d . V e g e t a t i o n s a m p l i n g was conducted a c c o r d i n g t o t h e B r a u n - B l a n q u e t method (Westhoff and van der M a a r e l 1980). Sample p l o t s were e s t a b l i s h e d i n a r e a s o f v i s u a l l y homogeneous 23 v e g e t a t i o n and topography i n t h e f o r e s t s and on t h e r i g h t s - o f -way. F o r e s t p l o t s were 20 m X 20 m (400 m^), where topography p e r m i t t e d , w h i l e on t h e t r a n s m i s s i o n l i n e r i g h t s - o f - w a y , p l o t s were 3 m X 3 m (9 m^). A minimum o f f i v e p l o t s was e s t a b l i s h e d i n each o f t h e v e g e t a t i o n u n i t s , o r e n t i t i e s , which had been t e n t a t i v e l y i d e n t i f i e d i n an i n i t i a l f i e l d r e c o n n a i s s a n c e , d u r i n g which t h e s t u d y a r e a s were i n v e s t i g a t e d t o de t e r m i n e t h e v a r i e t y and n a t u r e o f v e g e t a t i o n p a t t e r n s , and t h e p o s s i b l e e n v i r o n m e n t a l c o n d i t i o n s which c o r r e l a t e d w i t h t h e d i s t r i b u t i o n o f s p e c i e s . Cover o f each s p e c i e s (growing on m i n e r a l s o i l o r f o r e s t f l o o r m a t e r i a l s ) was r e c o r d e d , u s i n g t h e D o m i n - K r a j i n a s p e c i e s s i g n i f i c a n c e s c a l e (Mueller-Dombois and E l l e n b e r g 1974; Emanuel 1985). F i v e v e g e t a t i o n l a y e r s were r e c o g n i z e d : t r e e canopy; t a l l s hrubs (2-10 m); low shrubs (<2 m); h e r b s ; and b r y o p h y t e s , l i c h e n s , and s e e d l i n g s . Nomenclature f o l l o w e d H i t c h c o c k and C r o n q u i s t (1973) f o r v a s c u l a r p l a n t s , I r e l a n d e t a l . (1980) f o r b r y o p h y t e s , and Ha l e and C u l b e r s o n (1970) f o r l i c h e n s . A t o t a l o f 115 p l o t s were sampled s p e c i f i c a l l y f o r v e g e t a t i o n a n a l y s i s and c l a s s i f i c a t i o n . V e g e t a t i o n and e n v i r o n m e n t a l d a t a were a l s o r e c o r d e d f o r 47 p l o t s where s o i l was c o l l e c t e d f o r t h e e s t i m a t i o n o f t h e seed bank (Chapter 3 ) . T h i r t y p l o t s (at each s i t e ) l o c a t e d a l o n g t r a n s e c t s which had been e s t a b l i s h e d f o r t h e e s t i m a t i o n o f t h e seed r a i n (Chapter 4) and f o r a s t u d y o f t h e r e c o l o n i z a t i o n o f s c a r i f i e d p l o t s (Chapter 5) were a l s o i n c l u d e d . 24 The e n v i r o n m e n t a l and v e g e t a t i o n parameters r e c o r d e d f o r t h e p l o t s a r e l i s t e d i n Ta b l e 2.1: a l l parameters were measured o r e s t i m a t e d i n t h e f i e l d . The s u b j e c t i v e , c a t e g o r i c a l v a r i a b l e " d i s t u r b a n c e " r e c o r d e d f o r r i g h t - o f - w a y p l o t s was based on t h e p e r c e n t c o v e r o f m i n e r a l s o i l . The " r e l a t i v e c o v e r " (of humus, sod formed by t h e seeded g r a s s e s , and m i n e r a l s o i l ) e x p r e s s e d t h e p e r c e n t c o v e r o f each c a t e g o r y d i v i d e d by t h e sum o f t h e p e r c e n t c o v e r o f t h e t h r e e c a t e g o r i e s . R e l a t i v e m i n e r a l s o i l exposure was used as a measure o f t h e degree o f d i s t u r b a n c e . R e l a t i v e humus c o v e r i s a crude e s t i m a t e o f t h e p o t e n t i a l r e c o v e r y by r e s i d u a l v e g e t a t i o n . R e l a t i v e sod c o v e r p r o v i d e s an e s t i m a t e o f c o m p e t i t i o n , d u r i n g s e e d l i n g e s t a b l i s h m e n t , from t h e seeded g r a s s e s and legumes. 2.2.3 Data a n a l y s i s The v e g e t a t i o n d a t a were a n a l y z e d u s i n g r e c i p r o c a l a v e r a g i n g (RA) o r d i n a t i o n (ORDIFLEX; Gauch 1977) . T h i s i s an i n d i r e c t g r a d i e n t a n a l y s i s t e c h n i q u e i n which s p e c i e s o f s i m i l a r d i s t r i b u t i o n , and p l o t s o f s i m i l a r s p e c i e s c o m p o s i t i o n , a re p l a c e d near each o t h e r i n o r d i n a t i o n space. To i d e n t i f y v e g e t a t i o n u n i t s , a p r o c e d u r e termed " p r o g r e s s i v e f r a g m e n t a t i o n " was f o l l o w e d (Peet 1980) . In t h i s method, o u t l y i n g p l o t s a r e i d e n t i f i e d and removed i n r e p e a t e d o r d i n a t i o n s o f t h e d a t a . P l o t s w i t h a d i s t i n c t i v e s p e c i e s c o m p o s i t i o n can be i d e n t i f i e d , and t h e i r removal from t h e d a t a s e t p e r m i t s o t h e r , p r e v i o u s l y masked p a t t e r n s t o emerge. The d e c i s i o n t o remove p l o t s was 25 T a b l e 2.1 E n v i r o n m e n t a l and v e g e t a t i o n parameters r e c o r d e d f o r th e v e g e t a t i o n sample p l o t s (X = a l l p l o t s , + = some p l o t s , - = not a p p l i c a b l e ) . F o r e s t R i g h t - o f - w a y Parameter Hygrotope X X Slope p o s i t i o n X X Slope g r a d i e n t (%) X X Asp e c t (degrees) X X S o i l t e x t u r e c l a s s * + + Coarse fragment c o n t e n t o f m i n e r a l s o i l X + Humus form + + F o r e s t f l o o r d e p t h X + D i s t u r b a n c e ( h i g h o r low) - X Ground coverage (%) Humus X X M i n e r a l s o i l X X Sod - X Dead wood X X Rock/stone X X R e l a t i v e coverage (%) Humus - X Sod - X M i n e r a l s o i l - X V e g e t a t i o n s t r a t a coverage (%.) Tree X X Shrub X X Herb X X B r y o p h y t e s / l i c h e n s X X Numbers o f s p e c i e s X X * Canadian S o i l Survey Committee 1978 based on t h e i r p o s i t i o n i n a s c a t t e r diagram o f RA a x i s 1 and a x i s 2 s c o r e s , and on t h e s p e c i e s c o m p o s i t i o n o f t h e p l o t s . The s e r a i and f o r e s t e d v e g e t a t i o n d a t a were a n a l y z e d s e p a r a t e l y . Three o r d i n a t i o n s were performed on each d a t a s e t . A t each s t e p o f t h e a n a l y s i s , s p e c i e s o c c u r r i n g i n l e s s t h a n t h r e e p l o t s were removed. O r i g i n a l l y , t h e f o r e s t d a t a i n c l u d e d 74 p l o t s and 115 s p e c i e s , and t h e s e r a i d a t a i n c l u d e d - 1 4 8 p l o t s and 171 s p e c i e s . S y n t h e s i s t a b l e s produced by VTAB (Emanuel 1985), a v e g e t a t i o n t a b l e g e n e r a t i n g program implemented on t h e U n i v e r s i t y o f B r i t i s h Columbia mainframe computer, were used t o i d e n t i f y t h o s e s p e c i e s which were b o t h common t o one or more v e g e t a t i o n u n i t s and d i a g n o s t i c o f an i n d i v i d u a l u n i t . The $COMBINE o p t i o n was used t o g e n e r a t e t h e d i a g n o s t i c summary t a b l e s f o r h i g h e r l e v e l s i n t h e c l a s s i f i c a t i o n h i e r a r c h y . T h i s o p t i o n g i v e s e q u a l weight t o each o f t h e t a x a w i t h i n a h i g h e r l e v e l (e.g. p l a n t s u b a s s o c i a t i o n s w i t h i n an a s s o c i a t i o n ) r e g a r d l e s s of t h e number of p l o t s w i t h i n each t a x o n . Nomenclature of t h e v e g e t a t i o n u n i t s f o l l o w s t h e Code of P h y t o s o c i o l o g i c a l Nomenclature (Barkman e t a l . 1976). The Code s p e c i f i e s t h a t t h e endings o f names of t h e p l a n t t a x a used i n t h e name of t h e v e g e t a t i o n u n i t be L a t i n i z e d a c c o r d i n g t o s p e c i f i c r u l e s , and t h a t t h e name of t h e t a x o n of t h e dominant v e g e t a t i o n s t r a t u m (e.g., t h e t r e e l a y e r ) appear second. The f o l l o w i n g m o d i f i c a t i o n s are employed i n t h i s s t u d y , however: t h e names are A n g l i c i z e d , and t h e o r d e r o f t h e s p e c i e s names i s r e v e r s e d . 27 P r o j e c t i o n s o f t h e 95% c o n f i d e n c e e l l i p s e s o f t h e p r i n c i p a l components a n a l y s i s (PCA) a x i s s c o r e s o f t h e v e g e t a t i o n u n i t s on t h e f i r s t two component axes o f t h e v e g e t a t i o n d a t a are a l s o p r e s e n t e d . The c o n f i d e n c e e l l i p s e s a re a g r a p h i c a l r e p r e s e n t a t i o n o f t h e s p e c i e s s i g n i f i c a n c e d a t a which shows t h e b o u n d a r i e s , and t h u s t h e v a r i a b i l i t y (Owen and C h m i e l e w s k i 1985), of t h e groups i d e n t i f i e d u s i n g p r o g r e s s i v e f r a g m e n t a t i o n . C a n o n i c a l c o r r e l a t i o n a n a l y s i s (CCA) i s a m u l t i v a r i a t e t e c h n i q u e which d e t e r m i n e s how much o f t h e v a r i a b i l i t y i n two s e t s o f v a r i a b l e s can be e x p l a i n e d by t h e r e l a t i o n s h i p s between them. CCA was used t o a s s e s s t h e r e l a t i o n s h i p s between environment (the p r e d i c t o r v a r i a b l e s ) and v e g e t a t i o n (the response v a r i a b l e s ) f o r t h e f o r e s t and s e r a i p l o t s . F o r t h i s a n a l y s i s , PCA was used t o t r a n s f o r m s p e c i e s s i g n i f i c a n c e d a t a i n o r d e r t o remove dependencies ( G i t t i n s 1985) and reduce t h e number of v a r i a b l e s ( N i c h o l s 1977). CCA was t h e n p e r formed on t h e v e g e t a t i o n d a t a , r e p r e s e n t e d by p l o t s c o r e s on t h e f i r s t 3 PCA axes, and s e l e c t e d e n v i r o n m e n t a l p a r a m e t e r s . Slope p o s i t i o n and s l o p e g r a d i e n t , which determine machine a c c e s s , were s e l e c t e d f o r b o t h f o r e s t and r i g h t - o f - w a y a n a l y s e s . In a d d i t i o n , c o a r s e fragment c o n t e n t o f t h e m i n e r a l s o i l , which a f f e c t s h y g r o t o p e , and r e l a t i v e m i n e r a l s o i l exposure, an i n d i c a t o r o f t h e i n t e n s i t y o f d i s t u r b a n c e , were used i n t h e CCA of t h e f o r e s t and r i g h t - o f - w a y d a t a , r e s p e c t i v e l y . RA and o t h e r o r d i n a t i o n t e c h n i q u e s d e f i n e a number of axes which e f f i c i e n t l y summarize t h e o v e r a l l v a r i a b i l i t y between 28 i n d i v i d u a l p l o t s . In contrast, the aim of discriminant analysis (DA) i s to extract factors or axes which e f f i c i e n t l y summarize the discrimination between groups of plots (vegetation units) (Matthews 197 9) . In maximizing differences between groups while minimizing within-group variance, DA can be used to analyze a c l a s s i f i c a t i o n system. DA has been applied to vegetation data with reference to the determination of the discreteness of previously defined vegetation types by providing information on within- and between-type v a r i a b i l i t y . DA, conducted using SYSTAT (Wilkinson 1986), was used to calculate the distance between the units i d e n t i f i e d by progressive fragmentation, and to estimate the relationships between immature forest and early serai vegetation units (Figure 2.3). When used for descriptive, exploratory purposes, DA does not require that a number of r e s t r i c t i v e assumptions (i . e . , equality and homogeneity of dispersion), which are necessary for p r o b a b i l i s t i c interpretations, be met (Williams 1983). In the absence of s t a t i s t i c a l r e l i a b i l i t y , however, perceived patterns or relationships are at best suggestive, and should be used to generate hypotheses which can be tested (Williams 1983). The categorical (dependent) variable used i n DA was the vegetation unit to which plots had been assigned; the independent or predictor variables were PCA axis scores of the species significance data (species occurring i n 3 or more p l o t s ) . Legendre and Legendre (1983) caution that only those components corresponding to eigenvalues (variance) larger than the average 29 FOREST SERAL F i g u r e 2.3 A d i a g r a m m a t i c r e p r e s e n t a t i o n o f t h e d i s c r i m i n a n t a n a l y s e s p e r f o r m e d t o e s t i m a t e t h e r e l a t i o n s h i p s among and between immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s . (Minimum v a r i a n c e w h i c h a p r i n c i p a l component had t o e x p l a i n i n o r d e r t o be i n c l u d e d (Legendre and Legendre 1983)/ c u m u l a t i v e v a r i a n c e e x p l a i n e d by t h e axes i n c l u d e d i n each a n a l y s i s . ) 30 e i g e n v a l u e a r e i n t e r p r e t a b l e . The average v a r i a n c e was d e t e r m i n e d f o r each d a t a s e t , and o n l y t h o s e p r i n c i p a l components whose v a r i a n c e exceeded t h e average were used i n DA. The r a d i u s o f 95% c o n f i d e n c e spheres was c a l c u l a t e d as t h e square r o o t o f (X^2. _ g^/n) (Mardia e_t a l . . 1979) . The seeded agronomic g r a s s e s and legumes, and a l l t r e e s p e c i e s known or o b s e r v e d t o r e g e n e r a t e by s e e d i n g a l o n e (Alnus r u b r a , Pseudotsuqa m e n z i e s i i , P i n u s  c o n t o r t a , T h u i a p l i c a t a , and Tsuga h e t e r o p h y l l a ) were d e l e t e d from t h e f o r e s t X s e r a i a n a l y s i s . 2.3 R e s u l t s 2.3.1 V e g e t a t i o n c l a s s i f i c a t i o n F i g u r e 2.4 shows t h e sequence o f f r a g m e n t a t i o n o f t h e f o r e s t d a t a . The f i r s t v e g e t a t i o n u n i t s s e g r e g a t e d u s i n g r e c i p r o c a l a v e r a g i n g o r d i n a t i o n were i d e n t i f i e d as T h u i a - L y s i c h i t u m ( h e r e a f t e r c a l l e d t h e L y s i c h i t u m u n i t , 5 p l o t s ) and P i n u s -Dicranum - C l a d o n i a spp. (the C l a d o n i a u n i t , 4 p l o t s ) . The second o r d i n a t i o n r e s u l t e d i n t h e i d e n t i f i c a t i o n o f P i n u s -Dicranum - A m e l a n c h i e r (the A m e l a n c h i e r u n i t , 4 p l o t s ) and A l n u s - D r y o p t e r i s (the D r y o p t e r i s u n i t , 11 p l o t s ) . Pseudotsuqa -H o l o d i s c u s (the H o l o d i s c u s u n i t , 13 p l o t s ) , Tsuga - K i n d b e r q i a (the K i n d b e r q i a u n i t , 20 p l o t s ) , and A l n u s - M y c e l i s (the M y c e l i s u n i t , 11 p l o t s ) were i d e n t i f i e d f o l l o w i n g t h e t h i r d o r d i n a t i o n . T able 2.2 p r e s e n t s t h e d i a g n o s t i c c o m b i n a t i o n o f s p e c i e s f o r t h e immature f o r e s t v e g e t a t i o n u n i t s . A h i e r a r c h y o f 3 p l a n t o r d e r s , 5 p l a n t a l l i a n c e s , 6 p l a n t a s s o c i a t i o n s , and 2 p l a n t 31 F i g u r e 2.4 The sequence o f p r o g r e s s i v e f r a g m e n t a t i o n , u s i n g r e c i p r o c a l a v e r a g i n g (RA) o r d i n a t i o n , o f t h e f o r e s t v e g e t a t i o n d a t a i n t o v e g e t a t i o n u n i t s . S p e c i e s names (the f i r s t f o u r l e t t e r s o f t h e genus, and f i r s t t h r e e l e t t e r s o f t h e s p e c i f i c e p i t h e t ) are l o c a t e d a p p r o x i m a t e l y where t h e y appear i n t h e s i m u l t a n e o u s s p e c i e s o r d i n a t i o n produced by RA. a) 74 p l o t s and 76 s p e c i e s ; v a r i a n c e e x p l a i n e d = 15.5% by a x i s 1, 10.6% by a x i s 2; b) 65 p l o t s and 65 s p e c i e s ; v a r i a n c e e x p l a i n e d = 15.2% by a x i s 1, 8.4% by a x i s 2; c) 50 p l o t s and 58 s p e c i e s ; v a r i a n c e e x p l a i n e d = 13.6% by a x i s 1, 8.6% by a x i s 2. 10i 8SA IASAR LjfSIAME 80 60 x < 40 20 O O A CWDONIA PINUCON ,1. * * PsfirfMEN „*•* * * > <•« * * * ' 20 40 60 AXIS 1 8 0 100 FIRST R.A. ° the Lysichi tum unit A the Cladonia unit * unclassi f ied 100-8 0 -6 0 -X < 40 2 0 ' BNUCON O ~20 40 60 80 100 AXIS 1 SECOND R.A. O the Amelanchier unit A the Oryopteris unit DRYOEXP A A A A^HYFIL ' unclassi f ied 100-80 60-X < 4 0 -2 0 -AA A d>0 a KINOORE • • D cP Og 0 HOIA^IS R U B U U R S ° GAULS^A A • • — r « -20 40 60 AXIS 1 80 100 THIRD R.A. a O the Holodiscus unit A the Kindbergia unit • the Mycelis unit 33 T a b l e 2.2 D i a g n o s t i c c o m b i n a t i o n o f s p e c i e s f o r t h e v e g e t a t i o n u n i t s r e c o g n i z e d i n t h e immature f o r e s t s a d j a c e n t t o t h e Cheekye L o o p a n d M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . Code l e t t e r A B C D E F G Number of p l o t s (Diagnostic 4 4 13 20 17 11 5 Vegetation u n i t s value)* Presence c l a s s and mean s i g n i f i c a n c e * * and species Pseudotsuqa - G a u l t h e r i a p.o.*** G a u l t h e r i a s h a l l o n (dd,cd) 5 7 3 5 7.6 V 7 9 IV 5 2 I + 0 I +.0 S a l i x s c o u l e r i a n a (d) 3 2 7 3 + .6 II I 1 3 I + 5 II 1 4 Vaccinium p a r v i f o l i u m (d,c) 4 3 5 S 3.5 V 3 1 III 2 5 II 1 1 I +.5 Pinus - Dicranum p . a l l . and p.a. Dicranum scoparium  Pinus c o n t o r t a  Pleurozlum s c h r e b e r i  Polytrichum lunlperinum I +.0 I +.0 I +.0 Pinus - Dicranum - Cladonia spp. p.sa. Cladonia spp. Rhacomitrlum canescens  Spiraea d o u q l a 3 l i + .3 I +.0 I +.0 I +.0 I 1.5 Pinus - Dicranum - Amelanchier p.sa. Amelanchier a l n i f o l i a (d) 4 1. 1 Goodvera o b l o n q i f o l i a (d) 3 + . 0 II + 0 Hylocomium splendens (d) 2 1.8 4 1. 4 II 2 2 III 4 0 I 2 3 I 1 0 1 1.0 Linnaea b o r e a l i s (d) 3 3. 7 II 1 1 I + 0 I + 5 I + 5 Mahonia nervosa (d) 3 2. 7 IV 3 4 V 4 0 III 2 3 II 1 3 Thuia p l i c a t a (d,c) 3 2.4 5 3. 0 V 4 4 V 5 0 IV 3 7 IV 4 8 5 5.1 T r i e n t a l i s l a t i f o l i a (d) 4 +. 8 I + 0 III + 3 IV 1 3 II + 7 Pseudotsuqa - Holodiscus p . a l l . and p.a. Holodiscu3 d i s c o l o r (d) 2 1.8 3 2 7 IV 3.4 II 2 4 II 3 1 I + 0 Kindberqia oreqana (d) 2 + .3 2 + 3 IV 5.3 V 5 3 IV 2 5 III 2 9 1 + 2 Mahonia nervosa (d) 3 2 7 IV 3.4 V 4 0 III 2 3 II 1 3 Polvstichum munitum (d) 2 + 0 III 1.4 V 4 9 V 5 6 V 6 7 1 + 2 Pter i d i u m aquilinum (d,c) 2 1.8 3 2 2 V 3.8 V 4 1 V 4 5 II 2 3 1 + 2 Rubus urs i n u s (d) 2 + 0 III 1.5 III 1 5 V 3 4 III 1 7 Tsuqa - Kindberqia D.o.. Pseudotsuqa Kindberqia p . a l l . and P-a. Kindberqia oreqana (d,cd) 2 + .3 2 + 3 IV 5.3 V 5 3 IV 2 5 III 2 9 1 + 2 Mahonia nervosa (d,c) 3 2 7 IV 3.4 V 4 0 III 2 3 II 1 3 Pteridium aquilinum (d,c) 2 1.8 3 2 2 V 3.8 V 4 1 V 4 5 II 2 3 1 + 2 Thuja - T i a r e l l a p.o. Acer c i r c i n a t u m (d) I +.1 II 3 0 IV 4 7 III 4 3 4 4 4 Blechnum sp l c a n t Id) II + 0 III 1 5 4 1 6 Dr y o p t e r i s expansa (d) I 0 III 2 1 V 4 5 2 3 0 T i a r e l L a t r i f o l i a t a (d) I 0 II 2 2 IV 2 9 2 2 0 ( c o n t i n u e d ) 34 Table 2 .2 (continued) Code l e t t e r A B C D E F G Number of p l o t s (Diagnostic 4 4 13 20 17 11 5 Vegetation u n i t s value)* Presence c l a s s and mean s i g n i f i c a n c e * * and species Thu-la - Polvstichum p . a l l . Acer macrophvllum (d) I 1 5 III 3 2 IV 3 7 III 4 1 Galium t r i f l o r u m (d) II + 2 III 1 0 III + 0 Kindberaia oceqana (d) 2 + 3 2 + 3 IV 5 3 V 5 3 IV 2 5 III 2 9 1 + 2 Mahonia nervosa (d) 3 2 7 IV 3 4 V 4 0 III 2 3 II 1 3 Plaqiomnium ins i q n e (d) I + 0 II 2 0 III 1 4 Polvstichum munitum (d,cd) 2 + 0 III 1 4 V 4 9 V 5 6 V 6 7 1 + 2 Alnus - Mvcelis p.a. Betula p a p v r i f e r a <d) 2 1 1 2 + 0 I + 1 I 2 4 III 3 0 I + 2 3 3 0 Mvcelis murali3 (d) IV 1 0 I + 0 Pseudotsuqa m e n z i e s i i (d,cd) 5 4 6 5 4 7 V 6 8 V 7 0 V 5 0 II 3 4 Pteridium aaullinum (d,c) 2 1 8 3 2 2 V 3 8 V 4 1 V 4 5 II. 2 3 1 + 2 Rubus p a r v i f l o r u s ' (d) III 2 1 Rubus urs i n u s (d,c) 2 + 0 III 1 5 III 1 5 V 3 4 I l l 1 7 T r i e n t a l i s l a t i f o l l a - (d) 4 + 8 I + 0 III + 3 IV 1 3 II + 7 Alnus - D r v o p t e r i s p.a. Athvrium f i l i x - f e m i n a (d,c) II + 8 V 3 4 5 4 3 Drvopteris expansa (d,c) I + 0 III 2 1 V 4 5 2 3 0 Rubus s p e c t a b i l l s (d) I 1 2 IV 3 6 4 4 6 Sambucus racemosa (d) I 1 5 IV 3 5 1 1 6 T i a r e l l a t r i f o l i a t a (d) I + 0 II 2 2 IV 2 9 2 2 0 Alnus - Lvsichitum o . a l l . and p.a. Athvrium f i l i x - f e m i n a (d,c) II + 8 V 3 4 5 4 3 Blechnum spicant (d) II + 0 III 1 5 4 1 6 Cornu3 s e r i c e a (d) I 1 4 4 6 Equisetum pratense (d) I + 0 I + 0 3 2 0 Lvsichitum americanum (d,cd) I + 0 5 5 8 Oenanthe sarmentosa (d) 3 3 .5 * Diagnostic c r i t e r i a , defined by Pojar et a l . (1987): d = d i f f e r e n t i a l (species with presence class > 5.0 and two presence classes higher than i n other u n i t s of the same h i e r a r c h i c a l l e v e l ) ; dd = dominant d i f f e r e n t i a l (mean species s i g n i f i c a n c e > 5.0 and two s i g n i f i c a n c e classes higher than i n other units of the same h i e r a r c h i c a l l e v e l ) ; cd = constant dominant (presence c l a s s = V and mean 3pecies s i g n i f i c a n c e > 5.0); c = constant (presence c l a s s = V and mean species s i g n i f i c a n c e <, 5.0) . ** Species presence c l a s s code i s the frequency of specie3 occurrence i n a vegetation u n i t : I = 1-20% of p l o t s , II = 21-40%, III =» 41-60%, IV = 61-80%, V = >80%. Arabic numerals are used when there are <6 plots i n a group. Species s i g n i f i c a n c e values correspond to percent cover: + = 0.1-0.3% cover, 1 = 0.4-1.0%, 2 = 1.1-2.2%, 3 = 2.3-5.0%, 4 = 5.1-10.0%, 5 = 10.1-25.0%, 6 = 25.1-33.0%, 7 = 33.1-50.0%, 8 = 50.1-75.0%, 9 = >75.0%. *** p.o. = plant order; p . a l l . = plant a l l i a n c e ; p.a. = plant a s s o c i a t i o n ; p.3a. = plant subassociation. 35 s u b a s s o c i a t i o n s was d i s t i n g u i s h e d , c o n s i d e r i n g t h e sequence and s p a t i a l arrangement o f t h e u n i t s i d e n t i f i e d u s i n g p r o g r e s s i v e fragmentation,, and a f t e r an e x a m i n a t i o n o f s p e c i e s d i s t r i b u t i o n s u s i n g VTAB. A summary o f t h e mean s t a t u s f o r s e l e c t e d e n v i r o n m e n t a l and v e g e t a t i o n parameters f o r t h e immature f o r e s t v e g e t a t i o n u n i t s i s g i v e n i n T a b l e 2.3. A p r o j e c t i o n o f t h e 95% c o n f i d e n c e e l l i p s e s o f each v e g e t a t i o n u n i t i n t h e second growth f o r e s t a d j a c e n t t o t h e r i g h t s - o f - w a y , based on a PCA o f a l l s p e c i e s which o c c u r r e d i n t h r e e o f more p l o t s , i s shown i n F i g u r e 2.5. O v e r l a p between e l l i p s e s r e f l e c t s s i m i l a r i t y i n t h e f l o r i s t i c c o m p o s i t i o n o f t h e t y p e s . The e l l i p s e s show t h e f l o r i s t i c d i s t i n c t i v e n e s s o f t h e C l a d o n i a (A) and A m e l a n c h i e r (B) u n i t s , b o t h w i t h r e s p e c t t o each o t h e r and t o t h e o t h e r u n i t s . The p r o g r e s s i o n from t h e H o l o d i s c u s (C) t o D r y o p t e r i s (F) u n i t , as d i s p l a y e d on PCA I , r e f l e c t s a d e c r e a s e i n t h e s i g n i f i c a n c e o f G a u l t h e r i a s h a l l o n and Pseudotsuga m e n z i e s i i , and an i n c r e a s e i n t h e s i g n i f i c a n c e o f A l n u s r u b r a and D r y o p t e r i s expansa (see a l s o Table 2.7). The d i v e r g e n c e o f t h e C l a d o n i a , A m e l a n c h i e r and L y s i c h i t u m (G) u n i t s from t h e H o l o d i s c u s , K i n d b e r g i a (D), M y c e l i s (E) and D r y o p t e r i s u n i t s on PCA I I r e f l e c t s t h e low s i g n i f i c a n c e , o r absence, o f K i n d b e r g i a oregana, P o l y s t i c h u m munitum, and Pseudotsuga  m e n z i e s i i i n t h e former u n i t s . The f i r s t o r d i n a t i o n o f t h e r i g h t - o f - w a y d a t a r e s u l t e d i n th e s e g r e g a t i o n o f Oenanthe - Sparganium (the Sparganium u n i t , 10 p l o t s ) and A l n u s - Juncus e n s i f o l i u s (the Juncus e n s i f o l i u s u n i t , 5 p l o t s ) . The v e g e t a t i o n u n i t s P t e r i d i u m - G a u l t h e r i a - T h u i a 36 Tab l e 2.3 Average s t a t u s o f e n v i r o n m e n t a l and v e g e t a t i o n p a rameters f o r th e v e g e t a t i o n . u n i t s i d e n t i f i e d i n t h e immature f o r e s t a d j a c e n t t o t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f -way. V e g e t a t i o n u n i t A = C l a d o n i a , B = A m e l a n c h i e r , C = H o l o d i s c u s , D • = K i n d b e r a i a , E = M y c e l i s , F • = D r v o p t e r i s , G = L y s i c h i t u m . (- = not a p p l i c a b l e , + = t r a c e ) V e g e t a t i o n u n i t A B C D E F G (n) (4) (4) (13) (20) (17) (11) (5) S l o p e p o s i t i o n * 6 5.8 5.6 3.7 2.9 2 1 Slo p e g r a d i e n t (%) - 4 11 12 15 - -% Coarse fragments 20 15 31 26 32 16 29 F o r e s t f l o o r d epth (cm) 2.3 2.3 • 4.8 5.8 5.5 I 3.6 13.6 Ground coverage (%) Humus 50 53 74 73 73 78 48 M i n e r a l s o i l 0 0 0 + + 0 0 Dead wood 10 15 15 18 14 18 26 Rock/stone 40 33 11 9 11 2 -V e g e t a t i o n s t r a t a coverage (%) Tree 43 34 45 62 48 56 43 Shrub 59 58 67 34 24 25 44 Herb 2 10 7 18 31 52 44 B r y o p h y t e s / l i c h e n s 38 6 20 22 8 4 7 Numbers o f s p e c i e s Trees E v e r g r e e n 4 4 4 3 3 3 2 Deciduous 1 1 5 4 5 4 3 Shrubs E v e r g r e e n 1 3 3 5 3 2 0 Deciduous 4 6 11 13 18 13 9 Herbs 3 9 8 16 33 29 14 B r y o p h y t e s / l i c h e n s 8 8 9 10 10 9 6 T o t a l s p e c i e s 21 31 40 51 72 60 34 * c a l c u l a t e d as an average o f t h e f o l l o w i n g c a t e g o r i c a l v a l u e s : 1 = d e p r e s s i o n , 2 = l e v e l , 3 = lower s l o p e , 4 = m i d - s l o p e , 5 = upper s l o p e , 6 = c r e s t . 37 AXIS 1 Figure 2.5 A p r i n c i p a l components analysis (PCA) ordination of the means and 95% confidence e l l i p s e s for the forest vegetation units, i d e n t i f i e d using progressive fragmentation, on the f i r s t two component axes. Vegetation unit A = Cladonia, B = Amelanchier, C = Holodiscus, D = Kindberqia, E = Mycelis, F = Dryopteris, G = Lysichitum. 38 (the G a u l t h e r i a u n i t , 15 p l o t s ) and Rubus - A t h y r i u m (the A t h v r i u m u n i t , 5 p l o t s ) were i d e n t i f i e d f o l l o w i n g t h e second o r d i n a t i o n . The u n i t s r e c o g n i z e d a f t e r t h e t h i r d and f i n a l o r d i n a t i o n were P t e r i d i u m - G a u l t h e r i a - P o l v t r i c h u m (the P o l y t r i c h u m u n i t , 42 p l o t s ) , Rubus - P t e r i d i u m - Phleum (the Phleum u n i t , 31 p l o t s ) , and Rubus - P t e r i d i u m - M y c e l i s (the P t e r i d i u m u n i t , 40 p l o t s ) ( F i g u r e 2.6). In Table 2.4, t h e d i a g n o s t i c c o m b i n a t i o n s of s p e c i e s f o r t h e seven s e r a i v e g e t a t i o n u n i t s r e c o g n i z e d on t h e r i g h t s - o f - w a y a r e g i v e n . A h i e r a r c h y o f two p l a n t o r d e r s (one unnamed), t h r e e p l a n t a l l i a n c e s , f i v e p l a n t a s s o c i a t i o n s , and f o u r p l a n t s u b a s s o c i a t i o n s was e s t a b l i s h e d i n t h e same manner as f o r t h e f o r e s t v e g e t a t i o n d a t a . A summary o f t h e average s t a t u s o f s e l e c t e d e n v i r o n m e n t a l and v e g e t a t i o n parameters f o r t h e e a r l y s e r a i v e g e t a t i o n u n i t s i s g i v e n i n T a b l e 2.5. The e x t e n s i v e o v e r l a p between t h e Phleum (3) and P t e r i d i u m (4) u n i t s i n F i g u r e 2.7 s u g g e s t s t h a t d i f f e r e n t i a t i o n between t h e s e two u n i t s i n t h e f i e l d would be d i f f i c u l t , and t h a t t h e d i s t i n c t i o n between them, based on f l o r i s t i c c o m p o s i t i o n a l o n e , i s a r b i t r a r y . PCA I embodies a g r a d u a l m o i s t u r e g r a d i e n t , as i n d i c a t e d by a d e c r e a s e i n t h e s i g n i f i c a n c e o f G a u l t h e r i a s h a l l o n and an i n c r e a s e i n Rubus p a r v i f l o r u s , and i n d i r e c t l y r e f l e c t s d i s t u r b a n c e i n t h a t t h e c o v e r o f seeded s p e c i e s i n c r e a s e s from t h e G a u l t h e r i a (1) t o t h e Phleum u n i t (see a l s o Table 2.9). The d i s t i n c t i v e f l o r a s o f t h e Juncus e n s i f o l i u s (6) and Sparqanium (7) u n i t s account f o r t h e s e p a r a t i o n o f t h o s e u n i t s from each o t h e r and from t h e o t h e r u n i t s on PCA I I . 39 F i g u r e 2.6 The sequence o f p r o g r e s s i v e f r a g m e n t a t i o n , u s i n g r e c i p r o c a l a v e r a g i n g (RA) o r d i n a t i o n , o f t h e s e r a i v e g e t a t i o n d a t a i n t o v e g e t a t i o n u n i t s . S p e c i e s names (the f i r s t f o u r l e t t e r s o f t h e genus, and f i r s t t h r e e l e t t e r s o f t h e s p e c i f i c e p i t h e t ) are l o c a t e d a p p r o x i m a t e l y where t h e y appear i n t h e s i m u l t a n e o u s s p e c i e s o r d i n a t i o n produced by RA. a) 148 p l o t s and 116 s p e c i e s ; v a r i a n c e e x p l a i n e d = 11.4% by a x i s 1, 6.1% by a x i s 2; b) 133 p l o t s and 100 s p e c i e s ; v a r i a n c e e x p l a i n e d = 8.4% by a x i s 1, 6.3% by a x i s 2; c) 110 p l o t s and 86 s p e c i e s ; v a r i a n c e e x p l a i n e d = 8.7% by a x i s 1, 7.0% by a x i s 2. 40 100-8 0 4 60-X < 40 H 20-20 SALISIT A A A j y N C E N S FIRST R.A. SPAREME OENASAR O ° t h e Sparqon ium unit A the Juncua enaifolius unit * unclassi f ied 40 60 80 AXIS 1 100 100-80-60-x < 40-20-V A Q S ^ J P L I o o 20 40 60 AXIS . 1 CORNSER 80 100 SECOND R.A. ° the Gaultheria unit A the Athyrium unit unclassi f ied 100-80-60-IA A A A A A X < 40 20 0-0-A ^ A A A . L0LH Oor cPo RA A A • • g a a q_ • CPOLYMUN _ B • ao • o o O GAULSHA o ° o 0 oo o a <bo O Q MAH0NERO O ° o <© o  THIRD R.A. O the Polyt r ichum unit A the Phleum unit • the Pter id ium unit 20 40 60 AXIS 1 80 100 41 Table 2.4 Diagnostic combination of species for the early s e r a i vegetation units recognized on the Cheekye Loop and Malaspina rights-of-way. Code number 1 2 3 4 5 6 7 Number of p l o t s (Diagnostic 15 42 31 40 5 5 10 V e g e t a t i o n u n i t s v a l u e ) * Presence c l a s s and mean s i g n i f i c a n c e * * and species P t e r i d i u m - G a u l t h e r i a p . a l l . and p.a.*** G a u l t h e r i a s h a l l o n (d,cd) V 6. 9 V 5 7 I I 2 4 I + 0 Mahonia nervosa (d) I I I 2. 4 I I I 2 5 I + 0 I I 1 7 P t e r i d i u m - G a u l t h e r i a - Thuja p.sa. Linnaea b o r e a l i s (d) I I I 3. 1 1 1 9 I + 0 Pseudotsuqa m e n z i e s i i (d) IV 2. 3 11 1 0 I I + 0 I + 0 Thuia p l i c a t a (d) i y 3. 0 I I + 1 I + 0 I + 1 1 1. 0 Vaccinium p a r v i f o l i u m (d) IV 2. 8 II 1 0 I + 0 I + 0 P t e r i d i u m - G a u l t h e r i a - Polvtrlchum p sa. Alnus rubra (d) i 1. 3 IV 3 8 V 5 3 I I I 5 0 3 1. 2 5 4 8 Anaphalis marqaritacea (d) i +. 0 I I I 1 3 I I + 0 I I I 2 4 1 +. 0 Eoilobium a n q u s t i f o l i u m (d) II +. 4 IV 1 1 I I I 1 4 I I I 1 5 3 +. 6 Festuca r u b r a l (d) i +. 0 IV 4 0 V 5 5 IV 4 e 2 2. 4 1 + 0 Holodiscus d i s c o l o r (d) i 1. 3 I I I 3 0 I I 1 4 I I ¥ 5 Phleum p r a t e n s e l (d) I I I 2 2 V 5 3 I I 2 5 2 3. 4 P o l y t r i c h u m luniperinum (d) II 1. 2 IV 1 4 I I + 7 I ¥ 0 Rubus p a r v i f l o r u s (d) i + . 0 I I I 1 3 I I I 2 2 V 3 8 5 4. 1 Rubus u r s l n u s (d) I I 1. 2 IV 2 8 I I 1 0 I I I 3 3 1 1. 0 Rubus - Alnus p . a l l . Galium t r i f l o r u m (d) I + 0 I I I 1 4 I I I 3 1 3 1. 7 Rubus leucodermis (d) i + . 0 I I 1 0 IV 2 1 IV 3 0 3 2. 4 1 + 0 Rubus p a r v i f l o r u s (d,c) i + . 0 I I I 1 3 I I I 2 2 V 3 8 5 4. 1 Rubus - P t e r i d i u m p.a. Anaphalis marqaritacea (d) i +. 0 I I I 1 3 I I + 0 I I I 2 4 1 +. 0 Festuca r u b r a l (d) i + . 0 IV 4 0 V 5 5 IV 4 6 2 2. 4 1 + 0 P t e r i d i u m a q u i l i n u m (d) IV 4. 1 V 5 2 IV 4 0 IV 4 9 1 1. e Rubus u r s i n u s (d) II 1. 2 IV 2 8 I I 1 0 I I I 3 3 1 1. 0 Rubus - P t e r i d i u m - Phleum p.sa. Alnus rubra (d,cd) i 1. 3 IV 3 8 V 5 3 I I I 5 0 3 1. 2 5 4 8 Lollum perennel (d) I I + 3 IV 2 3 I + 0 Phleum p r a t e n s e l (d,cd) I I I 2 2 V 5 3 I I 2 5 2 3. 4 Prunus emarqinata (d) I I ¥ 0 IV + 6 I I 1 2 T r i f o l i u m hvbriduml (d) I ¥ 0 IV 3 6 I + 0 T r i f o l i u m r e o e n s l (d,c) I + 2 V 3 4 I + 0 1 + 2 (continued) 42 Table 2.4 (continued) Code number Number of p l o t s Vegetation u n i t s and species (Diagnostic v a l u e ) * X 15 2 3 4 5 6 7 42 31 40 5 5 10 Presence c l a s s and mean s i g n i f i c a n c e * * Rubus - Pteridium - Mycelis p.3a. Acer c i r c i n a t u m (d) I + 0 I + 0 III 4 6 1 + 2 Bet u l a p a p v r i f e r a (d) II 2 0 III 3 0 I •f 5 III 3 0 3 1 9 Mycelis muralis (d) I + 0 II + 4 I + 0 IV 2 3 Polystichum munitum (d) I + 7 I + 1 I + 0 III 3 4 2 1 0 Rubus p a r v i f l o r u s (d,c) I 0 III 1 3 III 2 2 V 3 8 5 4 1 Rubus s p e c t a b i l i s (d) I + 0 I + 0 III 2 9 5 5 9 Rubus - Athvrium p.a. Athyrium f i l i x - f e m i n a (d,c) II 1 0 5 3 7 Cornus s e r i c e a (d) I + 0 3 2 0 Lysichitum americanum (d) 3 2 6 Oenanthe sarmentosa (d,c) 5 2 0 Rubus s p e c t a b i l i s (d,cd) I + 0 I + 0 III 2 9 5 5 9 T i a r e l l a t r i f o l i a t a (d) I + 0 I + 1 3 1 8 Typha - Scirpus p . a l l . S cirpus microcarpus (d) I 0 1 2 4 Typha l a t i f o l i a (d,c) 1 + 0 Alnus - Juncus e n s i f o l i u s p.a. A q r o s t i s s t o l o n i f e r a (d) I +. 0 II 1 5 II 1 9 III 4 6 3 4 2 Alnus rubra (d,c) I 1 3 IV 3 8 V 5 3 III 5 0 3 1 2 Juncus e n s i f o l i u s <d,cd) S a l i x s i t c h e n s i s (d) I + 0 I + 3 + .2 4.5 4.2 Oenanthe - Sparqanlum p.a. I +.3 I 1.0 I +.6 I I I 4.5 V 4.9 I +.3 III 4.2 V 4. 6 I +.3 II 1.4 Carex a q u a t i l i s (d) 1 + .0 1 1.6 III 2 9 Carex a r c t a (d) I +.9 2 + .4 IV 4 4 C i c u t a d o u q l a s i i (d) I I I 4 4 Lysichitum americanum (d) 3 2.6 III 4 5 Oenanthe sarmentosa <d,c) 5 2.0 V 4 9 Sparqanlum emersum (d) IV 4 7 * Diagnostic c r i t e r i a as defined i n Table 2.3. ** Species s i g n i f i c a n c e as defined i n Table 2.3. *** p. a l l . = plant a l l i a n c e ; p.a. = plant association; p.sa. = plant subassociation. # Species i n the seed mix which was applied to the s i t e s a f t e r c l e a r i n g . 43 Table 2.5 Average e n v i r o n m e n t a l and v e g e t a t i o n parameters f o r the v e g e t a t i o n u n i t s i d e n t i f i e d on t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . V e g e t a t i o n u n i t 1 = G a u l t h e r i a , 2 = P o l y t r i c h u m , 3 = Phleum, 4 = P t e r i d i u m , 5 = A t h y r i u m , 6 = Juncus e n s i f o l i u s , 7 = Sparganium. (- = not a p p l i c a b l e o r not measured V e g e t a t i o n u n i t (n) 1 (15) 2 (42) 3 (31) 4 (40) 5 (5) 6 (5) 7 (10 Sl o p e p o s i t i o n * 5.4 4.7 3.2 3.4 1.6 1 1 Sl o p e g r a d i e n t (%) 10 6 1 9 2 - -% Coarse fragments 22 32 23 26 19 - -( n ) a (12) (40) (27) (33) (3) Ground coverage (%) 3^ Humus 72 44 3 47 47 _b M i n e r a l s o i l - 26 58 17 15 - -Dead wood 13 11 4 14 27 1 16 Sod - 8 28 18 11 - -Rock/stone 14 12 6 4 + - -R e l a t i v e coverage (%) Humus 100 58 3 58 67 - -Sod 0 10 32 22 15 - -M i n e r a l s o i l 0 32 66 20 18 - -V e g e t a t i o n s t r a t a coverage (%) Tree 1 6 1 15 2 1 1 Shrub 52 31 21 31 40 15 7 N a t i v e herb 12 17 12 25 24 55 78 Seeded herb + 10 40 20 20 3 + B r y o p h y t e s / l i c h e n s 5 3 4 1 - 1 -Numbers o f s p e c i e s Trees E v e r g r e e n 4 4 3 3 1 0 0 Deciduous 4 5 3 5 4 2 0 Shrubs E v e r g r e e n 4 2 3 2 0 0 0 Deciduous 12 21 13 19 10 5 6 Herbs 21 46 46 59 33 14 21 B r y o p h y t e s / l i c h e n s 11 19 12 11 0 2 0 T o t a l s p e c i e s 56 97 80 99 48 23 27 * c a l c u l a t e d as i n Table 2.3. a (n) = t h e number o f p l o t s f o r which c o a r s e fragment c o n t e n t was e s t i m a t e d . 5 3 t h e s u r f a c e o f p l o t s i n u n i t s 6 and 7 was c o v e r e d p r e d o m i n a n t l y by water. 44 -10 H 1 • : • r" -10 0 10 A X I S 1 Figure 2.7 A p r i n c i p a l components analysis (PCA) ordination of the means and 95% confidence e l l i p s e s of the s e r a i vegetation units, i d e n t i f i e d using progressive fragmentation, on the f i r s t two component axes. Vegetation unit 1 = Gaultheria, 2 = Polytrichum, 3 = Phleum, 4 = Pteridium, 5 = Athyrium, 6 = Juncus e n s i f o l i u s , 7 = Sparqanium. 45 A l l f o u r t e e n f o r e s t and s e r a i v e g e t a t i o n u n i t s were found a t t h e Cheekye Loop, w h i l e o n l y f o u r f o r e s t and f o u r s e r a i v e g e t a t i o n u n i t s were r e p r e s e n t e d a t M a l a s p i n a . A c c o r d i n g l y , many of t h e p l a n t s p e c i e s d i a g n o s t i c o f t h e f o r e s t u n i t s C l a d o n i a , A m e l a n c h i e r , and L y s i c h i t u m were not found a t M a l a s p i n a . S i m i l a r l y , d i a g n o s t i c s p e c i e s o f t h e Juncus  e n s i f o l i u s and Sparqanium u n i t s were absent from t h e M a l a s p i n a s i t e . I n a d d i t i o n , B e t u l a p a p y r i f e r a , A c e r c i r c i n a t u m , and P o p u l u s t r i c h o c a r p a were not r e p r e s e n t e d a t M a l a s p i n a . The w e s t e r n p o r t i o n o f t h e f o r e s t a t t h e Cheekye Loop, on t h e f l o o d p l a i n , was a mosaic of t h e M y c e l i s (E) and D r y o p t e r i s (F) u n i t s , i n t e r m i x e d w i t h s t a n d s o f t h e K i n d b e r q i a (D) u n i t ( F i g u r e 2.8, see a t t a c h e d ) . The c o l l u v i a l / r o c k y s l o p e t o t h e e a s t o f t h e f l o o d p l a i n was v e g e t a t e d by t h e M y c e l i s u n i t on t h e l o w e r - and m i d - s l o p e s , and K i n d b e r q i a and H o l o d i s c u s (C) on mid-and u p p e r - s l o p e s . The C l a d o n i a (A) and A m e l a n c h i e r (B) u n i t s were l o c a t e d on r i d g e c r e s t s , on s h a l l o w s o i l s over bedrock, a l o n g t h e n o r t h e r n f o r e s t boundary. The L y s i c h i t u m (G) p l a n t a s s o c i a t i o n was l o c a t e d on t h e s o u t h e r n edge o f t h e c e n t r a l g u l l y , i t s h i g h s o i l m o i s t u r e c o n t e n t m a i n t a i n e d by a permanent stream coming from t h e n o r t h . V e g e t a t i o n u n i t s o c c u p i e d t o p o g r a p h i c a l p o s i t i o n s t o t h e e a s t o f t h i s p o i n t which were s i m i l a r t o t h o s e west of t h e g u l l y . On t h e f l o o d p l a i n , t h e Cheekye Loop r i g h t - o f - w a y was dominated by t h e Phleum (3) u n i t , r e f l e c t i n g machine a c c e s s : t h e a r e a had been c l e a r e d t o m i n e r a l s o i l and t h e n seeded t o agronomic g r a s s e s and legumes. The v e g e t a t i o n o f t h e 46 r o c k y / c o l l u v i a l s l o p e s was dominated by t h e P t e r i d i u m (4) u n i t . Rock o u t c r o p s were p r e d o m i n a n t l y v e g e t a t e d by t h e G a u l t h e r i a (1) and P o l y t r i c h u m (2) u n i t s . The v e g e t a t i o n o f t h e c e n t r a l g u l l y , f e d by a permanent stream, c o m p r i s e d t h e Sparganium (7) u n i t i n a r e a s w i t h t h e water t a b l e above t h e s o i l s u r f a c e , and t h e A t h y r i u m (5) u n i t ( i n t e r m i x e d w i t h P t e r i d i u m ) on s i g h t l y h i g h e r ground. The Juncus e n s i f o l i u s (6) u n i t was l o c a t e d on an o l d e r t r a n s m i s s i o n l i n e r i g h t - o f - w a y b i s e c t i n g t h e s t u d y s i t e n ear i t s e a s t e r n edge. The t o p o g r a p h i c a l t r e n d a t t h e M a l a s p i n a r i g h t - o f - w a y i s o f a v e r y g r a d u a l , s l i g h t i n c r e a s e i n e l e v a t i o n towards t h e n o r t h . The v e g e t a t i o n o f t h e f o r e s t on t h e n o r t h e r n edge c o m p r i s e d t h e H o l o d i s c u s (C) u n i t on s h a l l o w s o i l s o v e r r o c k o u t c r o p s , w i t h t h e K i n d b e r g i a (D) and M y c e l i s (E) u n i t s i n lower a r e a s w i t h deeper s o i l s ( F i g u r e 2.9, see a t t a c h e d ) . The s o u t h e r n f o r e s t boundary was dominated by t h e K i n d b e r g i a u n i t on c o l l u v i a l s o i l s w i t h t h e M y c e l i s and D r y o p t e r i s (F) u n i t s i n a r e a s t o p o g r a p h i c a l l y above and a d j a c e n t t o streams, r e s p e c t i v e l y . The v e g e t a t i o n o f t h e M a l a s p i n a r i g h t - o f - w a y was dominated by a mosaic o f t h e P o l y t r i c h u m (2) and Phleum (3) s u b a s s o c i a t i o n s , t h e two v e g e t a t i o n u n i t s i d e n t i f i e d and d e s c r i b e d above which occupy more d i s t u r b e d s i t e s . The P t e r i d i u m (4) u n i t was found where t h e use o f heavy machinery was p r o b a b l y r e s t r i c t e d , and t h e A t h y r i u m (5) u n i t was found i n m o i s t d e p r e s s i o n s w i t h l i m i t e d machine a c c e s s . 47 2 . 3 . 2 C a n o n i c a l c o r r e l a t i o n a n a l y s i s The c a n o n i c a l c o r r e l a t i o n c o e f f i c i e n t , r c , i n d i c a t e s t h e degree o f l i n e a r c o r r e l a t i o n between t h e two c a n o n i c a l v a r i a t e s , h ere l a b e l e d "V" ( v e g e t a t i o n domain) and "E" (the environment domain). I n t r a s e t s t r u c t u r a l c o r r e l a t i o n s ( ^ i n t r a ^ e x p r e s s t h e s t r e n g t h and d i r e c t i o n o f t h e c o r r e l a t i o n between a c a n o n i c a l v a r i a t e and t h e v a r i a b l e s o f t h e same domain; i n t e r s e t c o r r e l a t i o n s ( ^ i n t e r ) c h a r a c t e r i z e t h e r e l a t i o n s h i p between t h e c a n o n i c a l v a r i a t e o f one domain and t h e v a r i a b l e s o f t h e o t h e r domain (e.g., V:environment v a r i a b l e s ) . The p e r c e n t o f t h e v a r i a n c e o f a v a r i a b l e w hich i s e x p l a i n e d by a c a n o n i c a l v a r i a t e o f t h e same domain i s e x p r e s s e d by ^ i n t r a ^ • T ^ e squared r ^ n t e r c o r r e l a t i o n i n d i c a t e s t h e p e r c e n t v a r i a n c e o f a v a r i a b l e p r e d i c t e d by t h e c a n o n i c a l v a r i a t e o f t h e o t h e r domain. A t o t a l o f 72.9% o f t h e v a r i a n c e o f t h e f o r e s t v e g e t a t i o n , as summarized by PCA I - I I I a x i s s c o r e s , i s e x p l a i n e d by t h e s e l e c t e d e n v i r o n m e n t a l parameters (Table 2 . 6 ) . E x a m i n a t i o n o f the c o r r e l a t i o n s o f t h e f o r e s t v e g e t a t i o n v a r i a b l e s w i t h V r e v e a l s t h a t o n l y PCA I (95.5% o f i t s v a r i a n c e e x p l a i n e d ) i s s i g n i f i c a n t l y c o r r e l a t e d w i t h V. The c o e f f i c i e n t s o f PCA I and I I d i f f e r i n s i g n from PCA I I I : V e x p r e s s e s some t r e n d - o r f e a t u r e o f PCA I and PCA I I t h a t i s t h e o p p o s i t e o f t h a t e x p r e s s e d by PCA I I I . The c o r r e l a t i o n s o f t h e f o r e s t e n v i r o n m e n t a l parameters w i t h E have t h e same s i g n (Table 2 . 6 ) , s u g g e s t i n g t h a t E r e p r e s e n t s a g r a d i e n t o f " d e c r e a s i n g " s l o p e p o s i t i o n ( i . e . , from c r e s t t o 48 T a b l e 2.6 C a n o n i c a l c o r r e l a t i o n a n a l y s i s o f immature f o r e s t v e g e t a t i o n (V) and environment (E) d a t a . C o r r e l a t i o n s s i g n i f i c a n t a t 0.05>p>0.01, *; a t p<0.01, **. C a n o n i c a l c o r r e l a t i o n V-E r c = .854 r c 2 = .729 V r i n t r a PCA I .977** PCA I I .028 PCA I I I -.210 V a r i a n c e e x t r a c t e d Redundancy r i n t r a r i n t e r r i n t e r .955 .834** .696 .001 .024 .001 .044 -.179 .032 .333 .243 .243 .243 E o V r i n t r a •••intra r i n t e r r i n t e r S lope p o s i t i o n -.998** . 996 -.852** .726 Slope g r a d i e n t -.218 .047 -.186 .034 Coarse fragments -.122 .015 -.104 .011 V a r i a n c e e x t r a c t e d .353 .257 Redundancy .257 .257 2 49 d e p r e s s i o n ) , d e c r e a s i n g s l o p e g r a d i e n t , and d e c r e a s i n g s o i l c o a r s e fragment c o n t e n t . Only s l o p e p o s i t i o n i s s i g n i f i c a n t l y c o r r e l a t e d w i t h E, however (99.6% o f t h e v a r i a n c e o f s l o p e p o s i t i o n i s e x p l a i n e d by E ) . T able 2.7 c o n t a i n s t h e c o r r e l a t i o n c o e f f i c i e n t s r e l a t i n g p l a n t s p e c i e s t o PCA I - I I I , V and E, d e r i v e d from t h e immature f o r e s t d a t a . PCA I and I I embody a d r y - t o - m o i s t g r a d i e n t w h i c h i s shown by n e g a t i v e c o r r e l a t i o n s w i t h P i n u s c o n t o r t a , P l e u r o z i u m  s c h r e b e r i , and Dicranum s c o p a r i u m and p o s i t i v e c o r r e l a t i o n s o f P o l y s t i c h u m munitum and A c e r macrophyllum t o t h e s e axes. In c o n t r a s t , PCA I I I embodies a w e t - t o - f r e s h g r a d i e n t as e x p r e s s e d by n e g a t i v e c o r r e l a t i o n s w i t h A t h y r i u m f i l i x - f e m i n a and L y s i c h i t u m americanum, and p o s i t i v e c o r r e l a t i o n s w i t h Rubus  u r s i n u s and S a l i x s c o u l e r i a n a . The i n t e r s e t c o r r e l a t i o n s o f i n t e r e s t are t h o s e which i n d i c a t e t h e i n f l u e n c e o f t h e environment on t h e v e g e t a t i o n . C o r r e l a t i o n s o f t h e PCA axes w i t h E show t h a t 69.6% o f t h e v a r i a n c e o f PCA I i s p r e d i c t a b l e from E. PCA I v a r i e s i n v e r s e l y w i t h E, as e v i d e n c e d by t h e n e g a t i v e c o r r e l a t i o n s f o r t h e e n v i r o n m e n t a l parameters and p o s i t i v e r j _ n t e r c o r r e l a t i o n f o r PCA I . F i g u r e 2.10 demonstrates t h i s r e l a t i o n s h i p . I t can be c o n c l u d e d t h a t s l o p e p o s i t i o n i s t h e p r i m a r y d e t e r m i n a n t o f f o r e s t v e g e t a t i o n c o m p o s i t i o n f o r t h e p l o t s examined i n t h i s s t u d y . In c o n t r a s t w i t h t h e f o r e s t d a t a , o n l y 59.8% o f t h e v a r i a n c e o f t h e s e r a i r i g h t - o f - w a y v e g e t a t i o n d a t a was e x p l a i n e d by t h e s e l e c t e d e n v i r o n m e n t a l parameters (Table 2.8). The c o r r e l a t i o n c o e f f i c i e n t s o f PCA I - I I I w i t h V are a l l s i g n i f i c a n t , 50 Ta b l e 2.7 C o r r e l a t i o n c o e f f i c i e n t s r e l a t i n g s p e c i e s t o PCA I - I I I and t o t h e c a n o n i c a l v a r i a t e s V ( v e g e t a t i o n ) and E (environment) f o r t h e f o r e s t d a t a . C o r r e l a t i o n s where p<0.01 are shown. S p e c i e s PCA I PCA I I PCA I I I E A l n u s r u b r a .763 .786 .607 D r y o p t e r i s expansa .646 .648 .480 A t h v r i u m f i l i x - f e m i n a .614 -.426 -.339 .659 .650 P o l y s t i c h u m munitum .605 .572 .551 .480 Rubus s o e c t a b i l i s .566 -.428 .601 .547 A c e r c i r c i n a t u m .565 .319 .484 .332 T i a r e l l a t r i f o l i a t a .529 .530 .454 Sambucus racemosa .470 .452 .377 Blechnum s p i c a n t .431 -.332 .484 .502 Oplopanax h o r r i d u s .409 -.326 .413 . .306 Disporum h o o k e r i .371 .343 M y c e l i s m u r a l i s .331 A c e r macrophyllum .328 .355 Tsuga h e t e r o p h y l l a .326 -.464 .423 L v s i c h i t u m americanum .318 -.498 -.399 .381 .432 D i c e n t r a formosa .310 Plagiomnium i n s i g n e .305 Cornus s e r i c e a .300 -.459 -.372 .358 .413 C h i m a p h i l a u m b e l l a t a -.305 -.312 Rhacomitrium canescens -.319 -.425 -.365 -.310 K i n d b e r g i a oregana -.325 .607 -.406 P o l y t r i c h u m i u n i p e r i n u m -.333 -.349 -.364 H o l o d i s c u s d i s c o l o r -.382 .360 -.443 Dicranum s c o p a r i u m -.428 -.433 -.468 -.378 P l e u r o z i u m s c h r e b e r i -.434 -.324 -.439 -.406 P i n u s c o n t o r t a -.494 -.552 -.560 -.483 V a c c i n i u m p a r v i f o l i u m -.554 -.553 -.518 Pseudotsuga m e n z i e s i i -.673 .552 -.656 -.559 G a u l t h e r i a s h a l l o n -.926 -.886 -.819 P t e r i d i u m a q u i l i n u m .459 Galium t r i f l o r u m .399 Rubus u r s i n u s .390 .486 Mahonia n e r v o s a .355 S p i r a e a d o u g l a s i i -.389 Equisetum p r a t e n s i s -.390 -.318 .344 Oenanthe sarmentosa -.405 -.314 .321 C l a d o n i a spp. -.460 -.343 S a l i x s c o u l e r i a n a .495 -.364 Rubus p a r v i f l o r u s .472 A l n u s s i n u a t a .342 T r i e n t a l i s l a t i f o l i a .320 Thuja p l i c a t a -.822 L u z u l a p a r v i f l o r a .300 Cornus c a n a d e n s i s .332 S m i l a c i n a s t e l l a t a .309 5 1 2n -2-F < O N D D LU Q-> D GO c D D C <-H fi C B -1 0 1 AXIS 2 ( E N V I R O N M E N T ) G F 2 ^ c E F i g u r e 2 . 1 0 S c a t t e r d i a g r a m o f i m m a t u r e f o r e s t p l o t s o n t h e a x e s r e s u l t i n g f r o m c a n o n i c a l c o r r e l a t i o n a n a l y s i s . V e g e t a t i o n u n i t A = C l a d o n i a , B = A m e l a n c h i e r , C = H o l o d i s c u s , D = K i n d b e r g i a , E = M y c e l i s , F = D r y o p t e r i s , G = L y s i c h i t u m 52 and t h e s i g n o f PCA I d i f f e r s from t h a t o f PCA I I and I I I , r e f l e c t i n g c o n t r a s t i n g g r a d i e n t s . PCA I r e p r e s e n t s a d r y - t o -f r e s h ( G a u l t h e r i a s h a l l o n t o Rubus p a r v i f l o r u s ) g r a d i e n t (Table 2.9). PCA I I r e p r e s e n t s a w e t - t o - d r y ( T y p h a . l a t i f o l i a t o G a u l t h e r i a s h a l l o n ) g r a d i e n t . PCA I I I embodies a complex g r a d i e n t which may be summarized as f o l l o w s : PCA I I I has n e g a t i v e c o r r e l a t i o n s t o t h e seeded s p e c i e s (e.g., F e s t u c a r u b r a , T r i f o l i u m hybridum) or n a t i v e s p e c i e s which r e g e n e r a t e by d i s p e r s e d seed (Alnus r u b r a , E p i l o b i u m a n g u s t i f o l i u m ) which i n c r e a s e d i n c o v e r a f t e r d i s t u r b a n c e , and t o f r e s h - s i t e s p e c i e s ( P t e r i d i u m a q u i l i n u m , T r i e n t a l i s l a t i f o l i a ) , and p o s i t i v e c o r r e l a t i o n s t o s p e c i e s which p e r s i s t e d d e s p i t e d i s t u r b a n c e (Mahonia n e r v o s a , A c e r c i r c i n a t u m , P o l y s t i c h u m munitum). V e x p l a i n e d 29.5%, 56.9%, and 13.7% o f t h e v a r i a n c e o f PCA I - I I I , r e s p e c t i v e l y . The c o r r e l a t i o n c o e f f i c i e n t s r e l a t i n g t h e e n v i r o n m e n t a l parameters and E are a l l s i g n i f i c a n t , w i t h 89.3% o f t h e v a r i a n c e o f s l o p e p o s i t i o n , 22.2% o f t h e v a r i a n c e o f s l o p e g r a d i e n t , and 11.3% o f t h e v a r i a n c e o f m i n e r a l s o i l exposure a c c o u n t e d f o r by E (Table 2.8). The s i g n o f t h e c o r r e l a t i o n c o e f f i c i e n t o f r e l a t i v e m i n e r a l s o i l exposure i s o p p o s i t e t o t h o s e o f s l o p e p o s i t i o n and s l o p e g r a d i e n t . T h i s i s c o n s i s t e n t w i t h an i n v e r s e r e l a t i o n s h i p between t h e s e v a r i a b l e s , r e f l e c t i n g machine a c c e s s . I n t e r s e t c o r r e l a t i o n s between t h e PCA axes and E i n d i c a t e t h a t 17.6%, 34% and 8.2% o f t h e v a r i a n c e o f PCA I - I I I , r e s p e c t i v e l y , i s p r e d i c t a b l e from E (Table 2.8). PCA I I and I I I v a r y d i r e c t l y w i t h s l o p e p o s i t i o n and s l o p e g r a d i e n t and 53 i n d i r e c t l y w i t h r e l a t i v e m i n e r a l s o i l c o v e r , w h i l e t h e r e v e r s e i s t r u e f o r PCA I . F i g u r e 2.11 demonstrates t h e r e l a t i o n s h i p between t h e e n v i r o n m e n t a l and v e g e t a t i o n p a r a m e t e r s . The environment a x i s ranges from d e p r e s s i o n t o c r e s t , f l a t t o s t e e p s l o p e g r a d i e n t , and h i g h t o low m i n e r a l s o i l e xposure. The v e g e t a t i o n a x i s r e p r e s e n t s a g r a d i e n t which ranges from w e t - s i t e n a t i v e s p e c i e s and seeded s p e c i e s t o d r y - s i t e s p e c i e s (Table 2.9) . 2.3.3 D i s c r i m i n a n t a n a l y s i s M a h a l a n o b i s ' s g e n e r a l i z e d d i s t a n c e , D^, e x p r e s s e s t h e d i s t a n c e s between o b j e c t s i n m u l t i d i m e n s i o n a l d i s c r i m i n a n t space (Legendre and Legendre 1983) . Here, D^ was used as an e x p r e s s i o n o f t h e f l o r i s t i c d i s t a n c e between i n d i v i d u a l p l o t s and t h e c e n t r o i d s o f each r e c o g n i z e d v e g e t a t i o n u n i t . The D^ v a l u e s a l s o p r o v i d e a means f o r comparing t h e homogeneity o f t h e groups. D i s t a n c e s f o r t h e f o r e s t d a t a a r e shown i n Ta b l e 2.10. V a l u e s a l o n g t h e d i a g o n a l r e p r e s e n t t h e mean d i s t a n c e o f members o f a v e g e t a t i o n u n i t t o t h e c e n t r o i d o f t h a t u n i t , and t h u s a r e not e q u a l t o 0. E x a m i n a t i o n o f t h e t a b l e r e v e a l s t h a t t h e mean D^ v a l u e s above t h e d i a g o n a l a re c l o s e , a l t h o u g h not i d e n t i c a l , t o t h o s e below t h e d i a g o n a l . T h i s i s due t o t h e v a l u e s above and below t h e d i a g o n a l b e i n g c a l c u l a t e d from, f o r example, t h e d i s t a n c e o f C l a d o n i a (A) p l o t s t o t h e A m e l a n c h i e r (B) c e n t r o i d , and v i c e v e r s a . F i g u r e 2.12 summarizes t h e d i s t a n c e s between t h e v e g e t a t i o n u n i t s on t h e f i r s t 3 d i s c r i m i n a n t axes. 54 Tab l e 2.8 C a n o n i c a l c o r r e l a t i o n a n a l y s i s o f t h e e a r l y s e r a i v e g e t a t i o n (V) and environment (E) d a t a . C o r r e l a t i o n s s i g n i f i c a n t a t 0.05>p>0.01, *; a t p<0.01, **. C a n o n i c a l c o r r e l a t i o n V-E r c = .773 r 2 = .598 PCA I PCA I I PCA I I I V r i n t r a r i n t r a ' -.543** .754** .370** .295 .569 .137 r i n t e r r i n t e r * -.420** .583** .286** .176 .340 .082 V a r i a n c e e x t r a c t e d Redundancy 333 199 199 199 • i n t r a • i n t r a S lope p o s i t i o n .945** .893 Slope g r a d i e n t .471** .222 R e l . m i n e r a l s o i l -.337** .113 V r i n t e r r i n t e r ' : .731** .364** -.260** .534 ,133 ,068 V a r i a n c e e x t r a c t e d Redundancy 409 245 245 245 55 3 - i 2 I : I I 1 1 - 3 - 2 - 1 0 1 2 AXIS 2 (ENVIRONMENT) Figure 2.11 Scatter diagram of early s e r a i p l o t s on the axes r e s u l t i n g from canonical c o r r e l a t i o n analysis. Vegetation unit 1 = Gaultheria, 2 = Polytrichum, 3 = Phleum, 4 = Pteridium, 5 = Athyrium, 6 = Juncus e n s i f o l i u s , 7 = Sparganium. 56 Tab l e 2.9 C o r r e l a t i o n c o e f f i c i e n t s r e l a t i n g s p e c i e s t o PCA I - I I I and t o t h e c a n o n i c a l v a r i a t e s V ( v e g e t a t i o n ) and E (environment) f o r t h e s e r a i v e g e t a t i o n d a t a . C o r r e l a t i o n s where p<0.01 a r e shown. * i n d i c a t e s seeded s p e c i e s . PCA PCA PCA S p e c i e s I I I I I I V E Rubus p a r v i f l o r u s .689 .454 F e s t u c a r u b r a * .602 .488 -.319 Rubus l e u c o d e r m i s .555 .252 A c r r o s t i s s t o l o n i f e r a .452 -.341 -.266 Phleum p r a t e n s e * .444 .388 -.461 Rubus s p e c t a b i l i s .404 -.223 -.310 -.225 A l n u s r u b r a .400 -.435 -.342 Galium t r i f l o r u m .396 .329 Sambucus racemosa .391 .222 Prunus e m a r q i n a t a .327 .235 T r i f o l i u m r e p e n s * .315 -.453 -.265 -.332 A c e r c i r c i n a t u m .306 . 635 T r i f o l i u m hybridum* .284 -.506 -.204 L o l i u m perenne* .273 .270 -.462 P o l y s t i c h u m munitum .273 .418 M y c e l i s m u r a l i s .269 . 626 .221 D i c e n t r a formosa .260 T i a r e l l a t r i f o l i a t a .235 A n a p h a l i s m a r q a r i t a c e a .232 .395 A t h y r i u m f i l i x - f e m i n a .229 -.318 -.300 -.258 R h y t i d i a d e l p h u s t r i q u e t r i s - .221 P a x i s t i m a m y r s i n i t e s - .222 Tsuqa h e t e r o p h y l l a - .222 A m e l a n c h i e r a l n i f o l i a - .223 Hylocomium s p l e n d e n s - .229 H i e r a c i u m a l b i f l o r u m - .249 .220 .301 .211 T h u i a p l i c a t a -.253 .219 .250 P i n u s c o n t o r t a - .253 L i l i u m columbianum - .265 .255 Dicranum s c o p a r i u m - .267 .249 Heuchera m i c r a n t h a - .267 .259 P o l y t r i c h u m i u n i p e r i n u m - .285 .308 .339 .233 Rhacomitrium canescens - .296 .218 .248 Mahonia n e r v o s a - .326 .260 .278 .476 .437 L i n n a e a b o r e a l i s - .357 .284 .239 V a c c i n i u m p a r v i f o l i u m - .380 .348 .376 Pseudotsuqa m e n z i e s i i - .436 .330 .349 G a u l t h e r i a s h a l l o n -.760 .514 .767 . 600 (continued) 57 T a b l e 2.9 (continued) PCA PCA PCA S p e c i e s I I I I I I V E P t e r i d i u m a q u i l i n u m .682 .351 .667 .434 H o l o d i s c u s d i s c o l o r .364 .261 .219 Poa p r a t e n s i s * .363 K i n d b e r q i a oreqana .326 -.265 .216 .245 Rubus u r s i n u s .306 .330 .330 .243 E p i l o b i u m a n q u s t i f o l i u m .220 .221 Carex spp. -.224 Juncus t e n u i s -.240 Lycopus u n i f l o r u s -.249 Cornus s e r i c e a -.270 T o r r e y c h l o a p a u c i f l o r a -.318 -.216 Juncus e n s i f o l i u s -.325 -.285 -.247 Carex canescens -.357 -.261 -.263 E p i l o b i u m w a t s o n i i -.380 -.333 -.317 S a l i x s i t c h e n s i s -.427 -.339 -.300 G l y c e r i a q r a n d i s -.427 -.285 -.256 S p i r a e a d o u q l a s i i -.441 -.351 -.397 Carex a q u a t i l i s -.489 -.325 -.286 C i c u t a d o u q l a s i i -.493 -.312 -.268 S a l i x l a s i a n d r a -.495 -.339 -.260 Carex a r c t a -.503 -.347 -.309 L y s i c h i t u m americanum -.508 -.351 -.276 S c i r p u s m i c r o f l o r u s -.554 -.402 -.338 Sparqanium emersum -.599 -.378 -.311 Oenanthe sarmentosa -.645 -.427 -.362 Typha l a t i f o l i a -.666 -.454 -.384 B e t u l a p a p y r i f e r a .578 .266 S a l i x s c o u l e r i a n a .358 .318 .267 Rhamnus p u r s h i a n a .297 A c e r macrophvllum .283 T r i e n t a l i s l a t i f o l i a .260 .229 .225 D a c t y l i s q l o m e r a t a -.219 58 T a b l e 2.10 Mean ( s t a n d a r d e r r o r o f t h e mean) Mah a l a n o b i s Dz d i s t a n c e s between t h e immature f o r e s t v e g e t a t i o n u n i t s . The s m a l l e s t v a l u e s , r e p r e s e n t i n g t h e d i s t a n c e from t h e p l o t s o f a u n i t t o t h e c e n t r o i d o f t h e u n i t t o which t h e y b e l o n g , ( a l o n g t h e d i a g o n a l ) a re u n d e r l i n e d . A box surrounds v a l u e s f o r p l a n t s u b a s s o c i a t i o n s w i t h i n a p l a n t a s s o c i a t i o n . V e g e t a t i o n u n i t A = C l a d o n i a , B = A m e l a n c h i e r , C = H o l o d i s c u s , D = K i n d b e r q i a , E = M y c e l i s , F = D r y o p t e r i s , G = L y s i c h i t u m . U n i t A B C D E F G (n) (4) (4) (13) (2.0) (17) (11) (5) A 1.70 5.00 10 .13 12 .75 13 .61 13 .39 16.02 (.14) (.23) ( .39) ( .23) ( .25) ( .28) (.42) B 5.00 1.37 5 .89 8 .84 10 .39 10 . 61 13.10 (.57) (.28) ( .35) ( .25) ( .25) ( .30) (.44) C 10.07 5.74 2 .20 4 .39 7 .24 8 .75 10.78 (.52) (.28) ( .15) ( .27) ( .20) ( .38) (.47) D 12.65 8.67 4 .43 2 .34 4 .75 7 .24 9.19 (.44) (.34) ( . 16) ( .15) ( . 18) ( .40) (.53) E 13.52 10.21 7 .19 4 . 65 2 .41 4 .83 7.35 (.30) (.48) ( . 12) ( .24) ( .17) ( .37) (.40) F 13.28 10.42 8 .76 7 .28 4 .84 2 .39 6.21 (.34) (.58) ( .12) ( .20) ( .30) ( .22) (.38) G 15.98 12.98 10 .83 9 .30 7 .43 6 .29 2.08 (.39) (.64) ( .16) ( .16) ( .27) ( .35) (.26) 59 D i s c r i m i n a n t a n a l y s i s s u p p o r t e d t h e c l a s s i f i c a t i o n system. DA c o n f i r m e d t h e r e c o g n i t i o n o f t h e d i s t i n c t i d e n t i t y o f t h e C l a d o n i a (A) and A m e l a n c h i e r (B) p l a n t s u b a s s o c i a t i o n s w i t h i n t h e P i n u s - Dicranum p l a n t a s s o c i a t i o n , as w e l l as t h e i r c l o s e n e s s . The C l a d o n i a and A m e l a n c h i e r p l a n t s u b a s s o c i a t i o n s are c l o s e r t o each o t h e r t h a n t o o t h e r u n i t s . F u r t h e r m o r e , t h e C l a d o n i a and A m e l a n c h i e r u n i t s a r e more homogeneous ( s m a l l e r D^) t h a n are t h e o t h e r u n i t s . The l a r g e s t d i s t a n c e s are between t h e C l a d o n i a and L y s i c h i t u m (G) u n i t s , t h e two extremes of t h e m o i s t u r e / t o p o g r a p h y g r a d i e n t . T a b l e 2.11 d i s p l a y s t h e c o r r e s p o n d i n g d i s t a n c e s f o r t h e s e r a i v e g e t a t i o n u n i t s . P l a n t s u b a s s o c i a t i o n s G a u l t h e r i a (1) and P o l y t r i c h u m (2) w i t h i n t h e P t e r i d i u m - G a u l t h e r i a a s s o c i a t i o n are r e l a t i v e l y c l o s e t o each o t h e r , as are t h e Phleum (3) and P t e r i d i u m (4) u n i t s w i t h i n t h e Rubus - P t e r i d i u m a s s o c i a t i o n . Note, however, t h a t t h e Phleum u n i t i s c l o s e ( f l o r i s t i c a l l y ) t o t h e P o l y t r i c h u m u n i t . Among t h e s e r a i ecosystems, th e l a r g e s t d i s t a n c e i s between t h e Juncus e n s i f o l i u s (6) and Sparqanium (7) u n i t s , b o t h of which had been a s s i g n e d t o t h e same p l a n t o r d e r and p l a n t a l l i a n c e . Thus, t h e r e s u l t s o f d i s c r i m i n a n t a n a l y s i s o f t h e s e r a i d a t a c h a l l e n g e t h e h i e r a r c h y d e r i v e d from t h e p r o g r e s s i v e f r a g m e n t a t i o n o f t h e v e g e t a t i o n d a t a . T h i s c l a s s i f i c a t i o n emphasized t h a t b o t h t h e Sparqanium and Juncus  e n s i f o l i u s u n i t s p o s s e s s e d S a l i x s c o u l e r i a n a , S c i r p u s  m i c r o f l o r u s , and Typha l a t i f o l i a . I n F i g u r e 2.13, t h e d i f f e r e n c e between Sparqanium and t h e o t h e r v e g e t a t i o n u n i t s i s emphasized. 60 Figure 2.12 A p r o j e c t i o n of the means and 95% confidence spheres of the immature forest vegetation units on the f i r s t 3 discriminant axes. Discrimination accounted for i s 60.2% on axis 1, 27.2% on axis 2, and 8.3% on axis 3. Vegetation unit A = Cladonia, B = Amelanchier, C = Holodiscus, D = Kindbergia, E = Mvcelis, F = Drvopteris, G = Lvsichitum. 61 T a b l e 2.11 Mean ( s t a n d a r d e r r o r o f t h e mean) Mahalanobis Dz d i s t a n c e s between t h e s e r a i v e g e t a t i o n u n i t s . The s m a l l e s t v a l u e s , r e p r e s e n t i n g t h e d i s t a n c e from t h e p l o t s o f a u n i t t o t h e c e n t r o i d o f t h e u n i t t o which t h e y b e l o n g , ( a l o n g t h e d i a g o n a l ) a r e u n d e r l i n e d . Boxes s u r r o u n d v a l u e s f o r p l a n t s u b a s s o c i a t i o n s w i t h i n a p l a n t a s s o c i a t i o n . V e g e t a t i o n u n i t 1 = G a u l t h e r i a , 2 = P o l y t r i c h u m , 3 = Phleum, 4 = P t e r i d i u m , 5 = A t h y r i u m , 6 = Juncus e n s i f o l i u s , 7 = Sparqanium. U n i t 1 2 3 4 5 6 7 (n (15) (42) (31) (40) (5) (5) (10) 1 1.76 4 .06 7 .05 7 .22 10 .16 12 .45 17.22 (.25) ( . 18) ( .21) ( .14) ( .36) ( .51) (.83) 2 3.91 2 .01 4 .92 5 .32 9 .04 11 .26 16.86 (.39) ( .09) ( .21) ( .17) ( .49) ( .53) (.86) 3 7.02 4 .90 2 .02 5 .98 9 .44 11 .40 17.00 (.28) ( .19) ( .12) ( .17) ( .56) ( .56) (.85) 4 7.03 5 .17 5 .80 2 .39 7 .14 11 .13 16.69 (.30) ( 8 .14) ( .23) ( .12) ( .63) ( .47) (.85) 5 9.96 .87 9 .27 7 .07 2 . 67 14 .13 13.17 (.25) ( .10) ( .18) ( • 17) ( .42) ( .46) (.80) 6 12.41 11 .27 11 .40 11 .20 14 .13 2 .13 18.94 (.32) ( .11) ( .20) ( .15) (1 .00) ( .17) (.89) 7 17.08 16 .73 16 .87 16 .59 13 .04 18 .80 3.75 (.15) ( .09) ( .12) ( .14) ( .72) ( .73) (.33) 62 The D 2 v a l u e s i n T a b l e 2.12 are based on two "ages"; immature f o r e s t and e a r l y s e r a i . The r e s u l t s o f DA u s i n g t h i s " c l a s s i f i c a t i o n " i m p l y t h a t p l o t s i n t h e f o r e s t a re more d i f f e r e n t from t h e "average" immature f o r e s t p l o t t h a n p l o t s on th e r i g h t s - o f - w a y a r e d i f f e r e n t from t h e "average" e a r l y s e r a i p l o t . A l s o , t h e immature f o r e s t u n i t s a re s l i g h t l y , but i n s i g n i f i c a n t l y , more homogeneous t h a n are t h e s e r a i u n i t s ( " U n i t " ) . T a ble 2.13 c o n t a i n s t h e g e n e r a l i z e d d i s t a n c e s between t h e e a r l y s e r a i and immature f o r e s t v e g e t a t i o n u n i t s . Only t h e s e r a l - t o - f o r e s t d i s t a n c e s a re shown: t h e s e a re based on more p l o t s t h a n a re t h e f o r e s t - t o - s e r a l d i s t a n c e s , and t h e r e f o r e may be more i n d i c a t i v e o f r e l a t i o n s h i p s . S e v e r a l r e l a t i o n s h i p s , based on f l o r i s t i c s i m i l a r i t i e s as i m p l i e d by low D 2 d i s t a n c e s , a r e s u g g e s t e d by DA (Table 2.13). The G a u l t h e r i a (1) u n i t i s f l o r i s t i c a l l y c l o s e t o t h e A m e l a n c h i e r (B) and H o l o d i s c u s (C) u n i t s . The P o l v t r i c h u m (2) u n i t i s a l s o f l o r i s t i c a l l y c l o s e t o t h e H o l o d i s c u s u n i t . The s p e c i e s c o m p o s i t i o n o f p l o t s i n t h e Phleum (3) u n i t i s comparable t o t h e K i n d b e r g i a (D) and M y c e l i s (E) u n i t s . The P t e r i d i u m (4) u n i t i s f l o r i s t i c a l l y s i m i l a r t o t h e M v c e l i s (E) u n i t . F i n a l l y , t h e f l o r a o f t h e A t h y r i u m (5) u n i t i s comparable t o t h e L y s i c h i t u m (G) u n i t . Compared t o t h e D 2 d i s t a n c e s r e l a t i n g t h e o t h e r e a r l y s e r a i v e g e t a t i o n u n i t s t o t h e f o r e s t v e g e t a t i o n u n i t s , t h e Juncus  e n s i f o l i u s (6) and Sparganium (7) u n i t s a re not c l e a r l y s i m i l a r t o any o f t h e f o r e s t u n i t s based on v e g e t a t i o n a l o n e . 63 Figure 2.13 A projection of the of the early s e r a i vegetation uni axes. Discrimination accounted fo axis , and 12.8% on axis 3. Vegetation unit 1 = Gaultheria, 3 = Phleum, 5 = Athyrium, 7 = Sparganium. eans and 95% confidence spheres s on the f i r s t 3 discriminant i s 56.8% on axis 1, 15.8% on 2 = Polytrichum, 4 = Pteridium, 6 = Juncus e n s i f o l i u s , > 64 Table 2.12 Mean ( s t a n d a r d e r r o r o f t h e mean) Mahalanobis D 2 d i s t a n c e s w i t h i n t h e immature f o r e s t and e a r l y s e r a i v e g e t a t i o n ("Age"), and o f p l o t s t o t h e c e n t r o i d o f t h e u n i t t o which t h e y b e l o n g ( " U n i t " ) . V e g e t a t i o n (n) "Age" " U n i t " F o r e s t (74) 0.98 2.07 (.09) (.37) S e r a i (148) 0.67 2.39 (.05) (.62) 65 Ta b l e 2.13 Mean d i s t a n c e s between t h e c e n t r o i d s o f ( w i t h i n columns), f o r e s t u n i t s , a r e S e r a i v e g e t a t i o n ( s t a n d a r d e r r o r o f t h e mean) Mahalanobis D 2 t h e e a r l y s e r a i p l o t s (by v e g e t a t i o n u n i t ) and th e f o r e s t v e g e t a t i o n u n i t s . Low D 2 v a l u e s s u g g e s t i v e o f r e l a t i o n s h i p between s e r a i and e n c l o s e d i n a box. u n i t s F o r e s t v e g e t a t i o n u n i t s U n i t (n) 1 (15) 2 (42) 1 = G a u l t h e r i a , 2 = P o l y t r i c h u m , 3 = Phleum, 4 = P t e r i d i u m , 5 = A t h y r i u m , 6 = Juncus e n s i f o l i u s . 7 = Sparaanium. A = C l a d o n i a , B = A m e l a n c h i e r , C = H o l o d i s c u s , D = K i n d b e r c r i a , E = M v c e l i s , F = D r v o p t e r i s . G = L y s i c h i t u m . 3 4 5 6 7 (31) (40) (5) (5) (10) A 9.37 (.41) B 4.19 (.29) C 4.21 (.14) D 5.59 (.24) E 6.88 (.22) F 8.76 (.18) 10.46 (.15) 6.14 (.16) 11.45 (.14) 5.11 (.18) 13.89 (.13) 5.73 (.15) 6.18 (.14) 8.21 (.10) 13.40 (.08) 7 .48 ( .18) 6 . 61 ( .20) 6 .10 ( .17) 5 .81 ( .15) 7.85 (.13) 12.98 (.08) 12.14 (.14) 8.86 (.15) 8.17 (.15) 7.47 (.16) 6.35 (.15) 8.05 (.18) 12.86 (.13) 14.26 (.22) 12.04 (.24) 11. 62 (.28) 11.24 (.26) 10.33 (.32) 10.15 (.35) 8.34 (1.25) 18.91 (.73) 15.38 (.83) 14.65 (.82) 14.52 (.85) 14.48 (.84) 15.02 (.73) 19. 62 (.63) 21.51 (.92) 20.40 (.97) 20.21 (.98) 19.85 (.99) 19. 64 (1.00) 20.37 (.98) 16.48 (.95) 66 2.4 D i s c u s s i o n 2.4.1 F o r e s t v e g e t a t i o n A Pseudotsuqa - G a u l t h e r i a p l a n t o r d e r , t o which t h e one d i s c u s s e d here i s comparable, was d e s c r i b e d by b o t h K r a j i n a (1969) and Roy (1984). A Pseudotsuqa - K i n d b e r q i a p l a n t a s s o c i a t i o n , s i m i l a r t o t h e one d e s c r i b e d h e r e , was a l s o i d e n t i f i e d by Roy (1984). The T h u i a - T i a r e l l a p l a n t a l l i a n c e ( K l i n k a 197 6) i s comparable t o t h e p l a n t o r d e r o f t h e same name which i s d i s c u s s e d h e r e . The A l n u s - L y s i c h i t u m p l a n t a s s o c i a t i o n d e s c r i b e d i n t h i s work i s comparable t o t h e L y s i c h i t u m americanum dominated p l a n t a s s o c i a t i o n s d e s c r i b e d by McMinn (1957) and Roy (1984). The concept of f o r e s t s i t e d i a g n o s i s i s based on t h e e v a l u a t i o n o f s i t e (topography o r p h y s i o g r a p h y ) , s o i l ( parent m a t e r i a l s , t e x t u r e ) , and v e g e t a t i o n p r o p e r t i e s ( K l i n k a e t a l . 1984). I t has l o n g been r e c o g n i z e d t h a t s o i l m o i s t u r e regime i s an i m p o r t a n t d e t e r m i n a n t of v e g e t a t i o n c o m p o s i t i o n . S l o p e p o s i t i o n , s l o p e g r a d i e n t , and s o i l c o a r s e fragment c o n t e n t a r e o f t e n i n t e g r a t e d t o e s t i m a t e s o i l m o i s t u r e regime. I n t h i s s t u d y , n e i t h e r c o a r s e fragment c o n t e n t (as recorded) , nor s l o p e g r a d i e n t c o n t r i b u t e d s i g n i f i c a n t l y t o t h e p r e d i c t i o n o f f o r e s t v e g e t a t i o n . D i f f e r e n t i a t i o n o f c o a r s e fragments i n t o two c l a s s e s , <2 cm, and >2 cm i n d i a m e t e r , may have r e s u l t e d i n a s t r o n g e r r e l a t i o n s h i p between v e g e t a t i o n and one or b o t h o f c o a r s e fragment c a t e g o r i e s . Slope p o s i t i o n was a p o w e r f u l p r e d i c t o r o f f o r e s t v e g e t a t i o n . 67 2.4.2 S e r a i v e g e t a t i o n The P t e r i d i u m - G a u l t h e r i a , Rubus - A t h y r i u m , and Oenanthe -Sparganium p l a n t a s s o c i a t i o n s i d e n t i f i e d u s i n g p r o g r e s s i v e f r a g m e n t a t i o n are s i m i l a r t o t h e G a u l t h e r i a s h a l l o n , P o l y s t i c h u m  muniturn and L y s i c h i t u m americanum a s s o c i a t i o n s , r e s p e c t i v e l y , w hich were d e s c r i b e d by Mueller-Dombois (1965) from c u t o v e r s on e a s t e r n Vancouver I s l a n d . B a i l e y and P o u l t o n (1968) d e s c r i b e d t h e p l a n t communities found on a p o r t i o n o f t h e T i l l a m o o k burn i n Oregon; t h e V a c c i n i u m p a r v i f o l i u m / G a u l t h e r i a s h a l l o n , A l n u s  rubra/Rubus p a r v i f l o r u s , and A l n u s r u b r a / P o l y s t i c h u m munitum a s s o c i e s which t h e y d e s c r i b e are s i m i l a r t o t h e G a u l t h e r i a , Phleum and P t e r i d i u m u n i t s , r e s p e c t i v e l y , t h a t are d e s c r i b e d h e r e . Among t h e v a r i a b l e s s e l e c t e d f o r use i n CCA, s l o p e p o s i t i o n was more i m p o r t a n t i n p r e d i c t i n g t h e immature f o r e s t v e g e t a t i o n t h a n i t was i n p r e d i c t i n g t h e e a r l y s e r a i v e g e t a t i o n . Other a u t h o r s have n o t e d t h a t a p a r t i c u l a r e a r l y s e r a i p l a n t community may o c c u r on d i f f e r e n t s i t e s (Daubenmire 1968; Matthews 1979; A l a b a c k 1984). F o r t h i s r e a s o n , i t i s s u g g e s t e d t h a t c h a r a c t e r i z a t i o n o f s u c c e s s i o n a l p l a n t communities on t h e b a s i s of v e g e t a t i o n c o m p o s i t i o n a l o n e i s i n s u f f i c i e n t ( K l i n k a e t a l . 1984, 1985). S i t e f e a t u r e s , such as t h e t y p e and i n t e n s i t y o f d i s t u r b a n c e , s h o u l d a l s o be i n c l u d e d i f an u n d e r s t a n d i n g o f f o r e s t v e g e t a t i o n dynamics i s sought (van H u l s t 1980). Slope p o s i t i o n and s l o p e g r a d i e n t d etermine machine a c c e s s f o r r i g h t - o f - w a y c l e a r i n g , which i n t u r n i n f l u e n c e s t h e amount 68 and c o m p o s i t i o n o f r e s i d u a l v e g e t a t i o n . R e l a t i v e m i n e r a l s o i l e xposure c o n t r i b u t e d s i g n i f i c a n t l y t o t h e p r e d i c t i o n o f s e r a i v e g e t a t i o n . Only 11.3% o f t h e v a r i a n c e o f r e l a t i v e m i n e r a l s o i l e xposure was a c c o u n t e d f o r by t h e c a n o n i c a l v a r i a t e o f t h e environment domain (E), however. T h i s i s p r o b a b l y p a r t l y due t o t h e e s t a b l i s h m e n t o f seeded g r a s s e s and o f o t h e r s p e c i e s (on b o t h m i n e r a l s o i l and humus) i n t h e t i m e t h a t l a p s e d between c l e a r i n g (1981), s e e d l i n g (1982), and v e g e t a t i o n s a m p l i n g (1983-4). W i t h i n t h e P t e r i d i u m - G a u l t h e r i a p l a n t a s s o c i a t i o n , t h e P o l y t r i c h u m v e g e t a t i o n u n i t was more d i s t u r b e d t h a n t h e G a u l t h e r i a u n i t . The P o l y t r i c h u m u n i t had g r e a t e r m i n e r a l s o i l e x posure, g r e a t e r c o v e r o f seeded s p e c i e s (and t h u s g r e a t e r sod c o v e r ) , and g r e a t e r c o v e r o f r e d a l d e r (Alnus rubra) and e a r l y s u c c e s s i o n a l herbs ( A n a p h a l i s m a r q a r i t a c e a , E p i l o b i u m  a n q u s t i f o l i u m ) t h a n d i d t h e G a u l t h e r i a u n i t . A s i m i l a r r e l a t i o n s h i p h e l d between t h e P t e r i d i u m and Phleum v e g e t a t i o n u n i t s w i t h i n t h e Rubus - P t e r i d i u m p l a n t a s s o c i a t i o n . The P t e r i d i u m u n i t was a p p a r e n t l y s i g h t l y w e t t e r and/or l e s s d i s t u r b e d t h a n t h e Phleum u n i t . A g a i n , t h e l a t t e r had g r e a t e r m i n e r a l s o i l exposure, g r e a t e r c o v e r o f seeded s p e c i e s , and g r e a t e r c o v e r o f r e d a l d e r . The n a t u r e o f t h e r e l a t i o n s h i p between m i n e r a l s o i l exposure and r e d a l d e r c o v e r i s i m p o r t a n t . On t h e s i t e s i n t h i s s t u d y , t h e r e l a t i o n s h i p s between r e d a l d e r , seeded g r a s s e s , and m i n e r a l s o i l exposure ( F i g u r e 2.14) i n d i c a t e s t h a t , d e s p i t e s e e d i n g w i t h agronomic s p e c i e s , t h e f r e q u e n c y and s i g n i f i c a n c e o f r e d a l d e r 69 i n c r e a s e s w i t h i n c r e a s i n g m i n e r a l s o i l e xposure. T h i s r e l a t i o n s h i p i s c o m p l i c a t e d by s o i l m o i s t u r e regime. 2.4.3 Immature f o r e s t - e a r l y s e r a i v e g e t a t i o n r e l a t i o n s h i p s D i s c r i m i n a n t a n a l y s i s o f t h e combined f o r e s t and s e r a i d a t a was used f o r two p u r p o s e s : f i r s t , t h e w i t h i n - " a g e " (immature f o r e s t v e r s u s e a r l y s e r a i ) average d i s t a n c e s were compared. R e s u l t s o f t h i s a n a l y s i s s u g g e s t e d t h a t t h e f o r e s t v e g e t a t i o n u n i t s a re more d i s t i n c t from each o t h e r t h a n a re t h e s e r a i v e g e t a t i o n u n i t s . The s e r a i v e g e t a t i o n was i n s i g n i f i c a n t l y more heterogeneous w i t h i n each u n i t t h a n was t h e f o r e s t v e g e t a t i o n . The c o n s t r a i n t s o f t h i s s t u d y ( i . e . , o n l y 2 "ages") p r o h i b i t t h e f o r m u l a t i o n o f a d e f i n i t i v e statement o f a t r e n d i n t h i s system. The g r e a t e r e f f i c i e n c y o f s l o p e p o s i t i o n i n p r e d i c t i n g t h e v e g e t a t i o n u n i t s ( s p e c i e s d i s t r i b u t i o n s ) o f t h e f o r e s t system (29-42 y e a r s o l d ) t h a n o f t h e s e r a i system (3-4 y e a r s o l d ) i s c o n s i s t e n t w i t h t h e f i n d i n g s of o t h e r s . The second purpose o f DA o f t h e combined d a t a was t o p r o v i d e a means by which t o propose which f o r e s t v e g e t a t i o n u n i t might have g i v e n r i s e t o which s e r a i v e g e t a t i o n u n i t . The q u e s t i o n was, t h e r e f o r e , not "what w i l l t h i s s e r a i v e g e t a t i o n u n i t become?", but r a t h e r , "what f o r e s t v e g e t a t i o n u n i t d i d i t come from?". A l t h o u g h s e r a l - t o - f o r e s t r e l a t i o n s h i p s might be' s u p p o r t e d by t h e i n v o c a t i o n o f t h e i n i t i a l f l o r i s t i c c o m p o s i t i o n model o f p l a n t s u c c e s s i o n ( E g l e r 1954), i t i s i n a p p r o p r i a t e t o answer t h e f i r s t q u e s t i o n . The f i r s t q u e s t i o n i s i n t r i g u i n g , 70 b) Xeric low Mesic high • Seeded grasses • Red alder • Mineral Soli F i g u r e 2.14 The r e l a t i o n s h i p between m i n e r a l s o i l exposure and the f r e q u e n c y and c o v e r of r e d a l d e r (mean s i g n i f i c a n c e ) and seeded g r a s s e s (% cover) on t h e t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . a) f r e q u e n c y ; b) c o v e r . x e r i c low ( d i s t u r b a n c e ) = u n i t 1, G a u l t h e r i a x e r i c h i g h = u n i t 2, P o l y t r i c h u m mesic low = u n i t 4, P t e r i d i u m mesic h i g h = u n i t 3, Phleum 71 but c o n s i d e r i n g t h e t i m e and s p a t i a l s c a l e s o f t h i s s t u d y , i t i s more r e a s o n a b l e t o answer t h e second q u e s t i o n . F u r t h e r m o r e , B.C. Hydro p o l i c y t o p r e v e n t f o r e s t e s t a b l i s h m e n t makes t h e p r e d i c t i o n o f p o t e n t i a l f o r e s t c o m p o s i t i o n on t h e s e s i t e s a moot p o i n t . I n t e r e s t i s f o c u s s e d on t h e p r e d i c t i o n o f r i s k t o power t r a n s m i s s i o n . The r e l a t i o n s h i p s i m p l i e d by DA were based on f l o r i s t i c c o m p o s i t i o n . E x a m i n a t i o n of t h e s i t e maps ( F i g u r e s 2.8 and 2 . 9 ) , s u g g e s t s r e l a t i o n s h i p s based on topography and d i s t u r b a n c e (machine access) (Table 2.14). Each of t h e t e n t a t i v e r e l a t i o n s h i p s i s d i s c u s s e d f u r t h e r below. F i g u r e 2.15a shows t h e arrangement of t h e d r y - s i t e f o r e s t and s e r a i v e g e t a t i o n u n i t s on t h e f i r s t t h r e e axes d e r i v e d d u r i n g d i s c r i m i n a n t a n a l y s i s . The e a r l y s e r a i u n i t s G a u l t h e r i a (1) and P o l y t r i c h u m (2) are f l o r i s t i c a l l y most s i m i l a r t o t h e immature f o r e s t u n i t s H o l o d i s c u s (C) and K i n d b e r q i a (D), r e s p e c t i v e l y . The G a u l t h e r i a and P o l y t r i c h u m u n i t s are found i n t o p o g r a p h i c p o s i t i o n s s i m i l a r t o t h e t h o s e i n which the C l a d o n i a (A), A m e l a n c h i e r (B) and H o l o d i s c u s u n i t s are found. F i g u r e 2.15b shows t h e f l o r i s t i c r e l a t i o n s h i p among t h e m e s i c - s i t e u n i t s . The e a r l y s e r a i Phleum (3) and P t e r i d i u m (4) v e g e t a t i o n u n i t s are c l o s e s t t o t h e immature f o r e s t M y c e l i s (E) u n i t , as s u g g e s t e d by T a b l e 2.13. When t o p o g r a p h i c p o s i t i o n and d i s t u r b a n c e are a l s o c o n s i d e r e d (Table 2.14), t h i s t e n t a t i v e r e l a t i o n s h i p i s not as c l e a r . 72 Table 2.14 Apparent t r a n s i t i o n s between immature forest and early s e r a i vegetation units based on species composition, topographic p o s i t i o n , and disturbance at the two study s i t e s , Vegetation units are ordered from dry, upper slope units to moist/wet units found i n depressions. Forest vegetation units Serai vegetation units A = Cladonia, B = Amelanchier, C = Holodiscus, D = Kindberaia, E = Mvcelis, F = Drvopteris, G = Lvsichitum. 1 = Gaultheria, 2 = Polvtrichum, 3 = Phleum, 4 = Pteridium, 5 = Athyrium, 6 = Juncus e n s i f o l i u s . 7 = Sparaanium. Low(er) disturbance High(er) disturbance Forest unit Serai uni t Forest unit Serai unit 73 F i g u r e 2.15 A p r o j e c t i o n o f t h e 95% c o n f i d e n c e spheres of immature f o r e s t and e a r l y s e r a i v e g e t a t i o n u n i t s on t h e f i r s t t h r e e d i s c r i m i n a n t axes, a) c) m o i s t - t o w e t - s i t e u n i t s F o r e s t v e g e t a t i o n u n i t s S e r a i v e g e t a t i o n u n i t s d r y - s i t e u n i t s ; b) m e s i c - s i t e u n i t s ; A = C l a d o n i a , B = A m e l a n c h i e r , C = H o l o d i s c u s , D = K i n d b e r q i a , E = M y c e l i s , F = D r y o p t e r i s , G = L y s i c h i t u m . 1 = G a u l t h e r i a , 2 = P o l y t r i c h u m , 3 = Phleum, 4 = P t e r i d i u m , 5 = A t h v r i u m , 6 = Juncus e n s i f o l i u s . 7 = Sparqanium. 75 A l l m o i s t / w e t - s i t e v e g e t a t i o n u n i t s a re i n c l u d e d i n F i g u r e 2.15c. The e a r l y s e r a i u n i t A t h y r i u m (5) i s c l e a r l y f l o r i s t i c a l l y c l o s e t o t h e L y s i c h i t u m (G) u n i t , as su g g e s t e d by Tab l e 2.13. The Juncus e n s i f o l i u s (6) u n i t i s c l o s e t o n e i t h e r o f t h e f o r e s t u n i t s . The Sparqanium (7) u n i t s h a r e s some s p e c i e s w i t h t h e L y s i c h i t u m u n i t (see T a b l e s 2.3 and 2.5), but a l s o has d i f f e r e n t s p e c i e s , p r o b a b l y r e f l e c t i n g exposure t o f u l l sun and a h i g h water t a b l e . The s u g g e s t e d r e l a t i o n s h i p s between f o r e s t and s e r a i v e g e t a t i o n u n i t s ( A m e l a n c h i e r / H o l o d i s c u s -> G a u l t h e r i a , L y s i c h i t u m -> Athyrium/Sparqanium) are t e n t a t i v e , y e t more o r l e s s o b v i o u s where r e s i d u a l v e g e t a t i o n i s abundant and t o p o g r a p h i c p o s i t i o n i s t h e same. The proposed r e l a t i o n s h i p between t h e M y c e l i s and Phleum u n i t s i s not as c l e a r o r s i n g u l a r : t h e M y c e l i s , K i n d b e r q i a , and D r y o p t e r i s u n i t s o c c u r r e d i n t h e same t o p o g r a p h i c p o s i t i o n i n t h e f o r e s t as d i d t h e Phleum and P t e r i d i u m u n i t s on t h e r i g h t s - o f - w a y . The s a m p l i n g o f t h e same v e g e t a t i o n u n i t s b e f o r e and a f t e r d i s t u r b a n c e s o f d i f f e r e n t i n t e n s i t i e s would answer t h e q u e s t i o n of r e l a t i o n s h i p / o r i g i n d i r e c t l y (Dyrness 1973). T h i s i s a r e t r o s p e c t i v e s t u d y , however, and i s t h u s l i m i t e d t o s u g g e s t i n g h y p o t h e t i c a l r e l a t i o n s h i p s . The v e g e t a t i o n d a t a were c o l l e c t e d t h r e e y e a r s a f t e r t h e c l e a r i n g o f t h e r i g h t - o f - w a y , and p r o v i d e o n l y a "snapshot" o f t h e p a t t e r n o f p l a n t s u c c e s s i o n t h a t w i l l o c c u r on t h e s e s i t e s . As t i m e p a s s e s , t h e d i s t r i b u t i o n , abundance and v i g o r o f r e d a l d e r , which c u r r e n t l y i s w i d e s p r e a d , w i l l p r o b a b l y change, and more i n d i v i d u a l s o f o t h e r t r e e s p e c i e s 76 w i l l become e s t a b l i s h e d . Repeated s a m p l i n g o f t h e same p l o t s over many y e a r s may suggest d i f f e r e n t r e l a t i o n s h i p s between t h e f o r e s t e d and s e r a i v e g e t a t i o n u n i t s s t u d i e d i n t h i s p r o j e c t . 2.5 C o n c l u s i o n s The r e s u l t s p r e s e n t e d here suggest t h a t t h e p r e d i c t i o n o f s u c c e s s i o n a l community c o m p o s i t i o n f o l l o w i n g c l e a r c u t t i n g o f t h e f o r e s t i s more or l e s s s t r a i g h t f o r w a r d where c o v e r o f r e s i d u a l v e g e t a t i o n i s h i g h . On t r a n s m i s s i o n l i n e r i g h t s - o f - w a y which have been c l e a r e d t o s t a n d a r d s C or D ( c l e a r c u t , stumps removed, graded, groomed, and seeded) p r e d i c t i o n i s d i f f i c u l t . The d a t a p r e s e n t e d here s t r o n g l y suggest t h a t s e e d i n g w i t h agronomic g r a s s e s and legumes does not i n t e r f e r e w i t h r e d a l d e r e s t a b l i s h m e n t where s i t e s have been c l e a r e d t o m i n e r a l s o i l . The s u c c e s s o f s e e d i n g u l t i m a t e l y depends on t h e t i m i n g o f f o r e s t c l e a r i n g , s c a r i f i c a t i o n , a p p l i c a t i o n of t h e seed of t h e agronomic s p e c i e s , and seed d i s p e r s a l by r e d a l d e r . 77 Chapter 3 The Seed Bank and Seed G e r m i n a t i o n 3.1 I n t r o d u c t i o n I n t e r e s t i n t h e r o l e o f t h e seed bank i n d e t e r m i n i n g t h e s p e c i e s c o m p o s i t i o n and t h e d e n s i t y o f v e g e t a t i o n which d e v e l o p s a f t e r d i s t u r b a n c e i s common t o a l l a p p l i e d r e s e a r c h e f f o r t s w i t h i n t h e b r o a d f i e l d o f v e g e t a t i o n management. In an a g r i c u l t u r a l c o n t e x t , seed banks have been s t u d i e d t o compare t h e e f f e c t s o f d i f f e r e n t c u l t u r a l t e c h n i q u e s and weed c o n t r o l p r a c t i c e s on weed seed p o p u l a t i o n s (Roberts 1981). Seed banks have a l s o been s t u d i e d i n t h e c o n t e x t o f t h e use o f s t r i p p e d t o p s o i l as a s o u r c e o f rhizomes and seeds i n t h e r e v e g e t a t i o n o f mined s i t e s (Beauchamp e t a l . 1975; Howard and Samuel 1979; Tacey and G l o s s o p 1980; Farmer e t a l . 1982). Olmstead and C u r t i s (1947) s u g g e s t e d t h a t knowledge of t h e abundance and k i n d s o f s p e c i e s p r e s e n t i n a f o r e s t seed bank c o u l d r e s u l t i n m o d i f i c a t i o n s o f s i l v i c u l t u r a l t r e a t m e n t s i n o r d e r t o reduce c o m p e t i t i o n or improve w i l d l i f e h a b i t a t . They o f f e r as an example the management of w h i t e p i n e (Pinus  m o n t i c o l a ) which was m o d i f i e d when i t was o b s e r v e d t h a t R i b e s , t h e a l t e r n a t e h o s t o f w h i t e p i n e b l i s t e r r u s t , r e a p p e a r e d i n c l e a r c u t and s l a s h burned o l d - g r o w t h s t a n d s o f w h i t e p i n e from which i t had been e l i m i n a t e d o ver t h e c o u r s e o f s u c c e s s i o n (Davis and Moss 1940). 78 O b s e r v a t i o n s r e g a r d i n g seed l o n g e v i t y and s u r v i v a l o f b o t h c r o p and non-crop s p e c i e s a r e v a l u a b l e . They can p r o v i d e i n f o r m a t i o n t o a s s i s t i n t h e f o r m u l a t i o n o f g u i d e l i n e s on t i m e l i m i t s f o r adequate n a t u r a l r e g e n e r a t i o n (e.g., F r a s e r 1976) or c u t t i n g sequences which would e l i m i n a t e c o m p e t i t i o n from weed t r e e s (Granstrom and F r i e s 1985), o r t o p r e d i c t t h e impact o f d i s t u r b a n c e i n t e n s i t y on r e g e n e r a t i o n from seed (Moore and Wein 1977; Morgan and Neuenschwander 1988) . The s t u d y o f seed banks i s not u n c o m p l i c a t e d , however. Major and P y o t t (1966) r e v i e w e d many of t h e problems i n h e r e n t i n the d e t e r m i n a t i o n of b u r i e d v i a b l e seed p o p u l a t i o n s . Foremost . among t h e s e d i f f i c u l t i e s i s t h e s e l e c t i v e environment imposed on seed p o p u l a t i o n s under c o n t r o l l e d s t o r a g e and g e r m i n a t i o n c o n d i t i o n s . W ith few e x c e p t i o n s ( S t r i c k l e r and E d g e r t o n 1976; P r a t t e t a l . 1984; Granstrom 1987), f o r e s t seed bank s t u d i e s have u t i l i z e d a s i n g l e s t r a t i f i c a t i o n p r o c e s s and a s i n g l e g e r m i n a t i o n regime f o r a l l samples. Secondly, t h e a g g r e g a t i o n o f seeds around mother p l a n t s ( i . e . , t h e non-randomness o f seed d i s t r i b u t i o n and t h e g r e a t number o f samples r e q u i r e d t o a t t a i n s t a t i s t i c a l r e l i a b i l i t y ) makes s t a t i s t i c a l a n a l y s i s d i f f i c u l t . Because o f t h i s second p o i n t , Whipple (1978) s u g g e s t e d t h a t seed bank samples be viewed as e s t i m a t e s o f s p e c i e s p r e s ence and not as e s t i m a t e s o f seed d e n s i t i e s . Because o f t h e f a c t o r s mentioned above, greenhouse-generated i n f o r m a t i o n on t h e s p e c i e s c o m p o s i t i o n , seed d e n s i t y , and d e p t h d i s t r i b u t i o n o f a seed bank i s merely an e s t i m a t e o f t h e p o t e n t i a l s e e d l i n g p o p u l a t i o n o f a s i t e . S p e c i e s - s p e c i f i c 79 f a c t o r s such as t h e d u r a t i o n o f seed v i a b i l i t y , dormancy mechanisms, s u b s t r a t e p r e f e r e n c e s , l i g h t and m o i s t u r e r e q u i r e m e n t s , and a b i l i t y t o g erminate from depth, d e t e r m i n e t h e r esponse of seeds t o b u r i a l o r exposure. The o b j e c t i v e s o f t h i s s t u d y were t o c h a r a c t e r i z e t h e s p e c i e s c o m p o s i t i o n and d e n s i t y o f b u r i e d v i a b l e seeds i n f o r e s t e d and d i s t u r b e d ( t r a n s m i s s i o n l i n e r i g h t - o f - w a y ) s o i l s , and t o e s t i m a t e t h e i n f l u e n c e o f s e v e r a l f a c t o r s on t h e g e r m i n a t i o n o f s e l e c t e d s p e c i e s . The f i r s t o b j e c t i v e was met by s a m p l i n g s o i l s o f d i f f e r e n t f o r e s t e d and d i s t u r b e d v e g e t a t i o n t y p e s and r e c o r d i n g seed g e r m i n a t i o n under greenhouse c o n d i t i o n s . The second o b j e c t i v e was met by comparing greenhouse t o f i e l d g e r m i n a t i o n f o r i m p o r t a n t seed bank s p e c i e s , and by c o n d u c t i n g e x p e r i m e n t s t o d e t e r m i n e t h e i n f l u e n c e of depth of b u r i a l , s u b s t r a t e , shade, and m o i s t u r e on t h e g e r m i n a t i o n o f s e l e c t e d s p e c i e s . T h i s was done t o e s t i m a t e t h e impact of d i s t u r b a n c e on g e r m i n a t i o n . 3.2 Methods 3.2.1 The seed bank 3.2.1.1 The s t u d y s i t e s Seed bank s o i l samples were c o l l e c t e d from th e f o r e s t s a d j a c e n t t o , and t h e communities on, two t r a n s m i s s i o n l i n e r i g h t s - o f - w a y B r i t i s h Columbia. The Cheekye Loop (10 km n o r t h o f Squamish) and M a l a s p i n a (30 km n o r t h w e s t of S e c h e l t ) 500 kV 80 t r a n s m i s s i o n l i n e r i g h t s - o f - w a y were c l e a r e d between September 1980 and December 1981. At t h e t i m e of c l e a r i n g , t h e f o r e s t s were a p p r o x i m a t e l y 26 and 39 y e a r s o l d , r e s p e c t i v e l y . Both f o r e s t s had a t t a i n e d canopy c l o s u r e , and were 15-30 m t a l l . S e v e r e l y d i s t u r b e d a r e a s on b o t h r i g h t s - o f - w a y were seeded t o a mix o f agronomic g r a s s e s and legumes ( i n c l u d i n g F e s t u c a r u b r a , L o l i u m perenne, Phleum p r a t e n s e , Poa p r a t e n s i s , T r i f o l i u m  hybridum, and T. repens) a t a r a t e o f a p p r o x i m a t e l y 28 kg/ha i n 1982 t o c o n t r o l e r o s i o n and impede t h e e s t a b l i s h m e n t o f r e d a l d e r (Alnus r u b r a ) . 3.2.1.2 Sample c o l l e c t i o n S o i l samples were c o l l e c t e d between 22 March and 1 A p r i l 1984, a f t e r d i s p e r s a l of t h e 1983 seed c r o p and b e f o r e t h e s p r i n g g e r m i n a t i o n f l u s h . Samples were c o l l e c t e d from d r y , i n t e r m e d i a t e , and m o i s t v e g e t a t i o n t y p e s a l o n g t h e t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . V e g e t a t i o n t y p e s were i d e n t i f i e d s u b j e c t i v e l y , u s i n g topography and v i s u a l e s t i m a t e s o f s p e c i e s c o v e r and c o m p o s i t i o n as c r i t e r i a . S o i l samples were c o l l e c t e d from p l o t s r e p r e s e n t i n g " u n d i s t u r b e d " immature f o r e s t ( a d j a c e n t t o t h e r i g h t s - o f - w a y ) , "low d i s t u r b a n c e " ( f o r e s t f l o o r i n t a c t and h i g h c o v e r o f r e s i d u a l o r r e s p r o u t i n g s p e c i e s , c o r r e s p o n d i n g t o s t a n d a r d A o r B c l e a r i n g ; see C h a p t e r s 1 and 2 ) , and " h i g h d i s t u r b a n c e " ( f o r e s t f l o o r d i s t u r b e d o r removed and l i t t l e r e s i d u a l v e g e t a t i o n , c o r r e s p o n d i n g t o s t a n d a r d C o r D c l e a r i n g ) s e r a i v e g e t a t i o n on t h e t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . The 81 v e g e t a t i o n o f t h e p l o t s was sampled d u r i n g t h e summer o f 1984/ and was l a t e r c l a s s i f i e d (Chapter 2 ) . F i v e randomly l o c a t e d samples, c u t w i t h a 20 cm X 20 cm t e m p l a t e ( s u r f a c e a r e a = .04 m^) were t a k e n from each p l o t , r e s u l t i n g i n a t o t a l o f .2 m^  sampled p e r p l o t . The f o r e s t f l o o r , o f v a r i a b l e d epth ( l i t t e r , f e r m e n t a t i o n , and humus l a y e r s combined), was c u t w i t h a k n i f e and c a r e f u l l y removed. The 0-5 cm, and 5-10 cm depths o f t h e m i n e r a l s o i l were removed w i t h a hand t r o w e l . Where an o b s t r u c t i o n (rock, r o o t ) was en c o u n t e r e d , t h e sample was c o l l e c t e d t o t h e depth o f t h e o b s t a c l e . Each l a y e r o f each sample was p l a c e d i n a l a b e l l e d p l a s t i c bag. A l l samples were s t o r e d , a t f i e l d water c o n t e n t , i n da r k n e s s a t 3°C u n t i l 3-7 May, when t h e y were p r e p a r e d and p o t t e d . A l l t h r e e l a y e r s were sampled i n t h e f o r e s t p l o t s . The 5-10 cm m i n e r a l s o i l l a y e r was e x p e c t e d t o have few g e r m i n a b l e seeds. F u r t h e r m o r e , t h e t r u e sample depth o f t h e h i g h d i s t u r b a n c e p l o t s , r e l a t i v e t o t h e o r i g i n a l s o i l p r o f i l e , was u n c e r t a i n i n t h a t s c a r i f i c a t i o n removed t h e f o r e s t f l o o r and p r o b a b l y some m i n e r a l s o i l . Because o f t h e s e f a c t s , t h e 5-10 cm m i n e r a l s o i l l a y e r was not sampled i n t h e low and h i g h d i s t u r b a n c e p l o t s . Thus, i n t h e low d i s t u r b a n c e p l o t s , t h e f o r e s t f l o o r and 0-5 cm m i n e r a l s o i l l a y e r s were sampled. By d e f i n i t i o n , t h e f o r e s t f l o o r was l a c k i n g or s e v e r e l y d i s t u r b e d i n t h e h i g h d i s t u r b a n c e p l o t s on t h e t r a n s m i s s i o n l i n e r i g h t s - o f - w a y : o n l y t h e 0-5 cm m i n e r a l s o i l l a y e r , w i t h i n c o r p o r a t e d f o r e s t f l o o r m a t e r i a l s i f p r e s e n t , was c o l l e c t e d from t h e s e p l o t s . 82 3.2.1.3 Sample p r e p a r a t i o n and g e r m i n a t i o n regimes F o r each m i n e r a l s o i l and f o r e s t f l o o r l a y e r w i t h i n each p l o t , t h e f i v e r e p l i c a t e samples were combined, t h o r o u g h l y mixed, and p a s s e d t h r o u g h a 12 mm mesh s c r e e n t o remove l e a v e s , t w i g s and r o c k s . The b u l k e d sample was t h e n s u b d i v i d e d i n t o 2 subsamples, each o f which was p l a c e d i n 12 cm X 8 cm X 6 cm p l a s t i c p o t s which had been f i l l e d t o a depth o f 4 cm w i t h s t e r i l i z e d sandy loam s o i l . The maximum depth o f t h e subsample was 1.5 cm. The number o f p o t s r e q u i r e d t o h o l d each subsample v a r i e d w i t h t h e depth and c o a r s e m a t e r i a l c o n t e n t o f t h e o r i g i n a l samples. The 2 subsamples were a r r a n g e d i n f l a t s ; 1 was p l a c e d on a greenhouse bench, and i n a c u l t i v a t e d e x p e r i m e n t a l f i e l d ( F i g u r e 3.1) on t h e UBC campus 2 km from t h e greenhouse. . t h e experiment was begun on May 5, 1984. A l l samples were wat e r e d d a i l y , o r l e s s , as needed. S e e d l i n g t a l l i e s were made a p p r o x i m a t e l y e v e r y 2 weeks a t t h e b e g i n n i n g o f t h e exper i m e n t , and monthly l a t e r . S e e d l i n g s were count e d and removed when t h e y c o u l d be i d e n t i f i e d . I f n e c e s s a r y , s e e d l i n g s were t r a n s p l a n t e d and a l l o w e d t o grow u n t i l t h e y c o u l d be p o s i t i v e l y i d e n t i f i e d . Samples i n t h e greenhouse were s t i r r e d t h r e e t i m e s t o promote g e r m i n a t i o n . The f i n a l greenhouse t a l l y was made on 15 November, 27.5 weeks a f t e r t h e experiment was begun. In o r d e r t o s i m u l a t e a s i n g l e d i s t u r b a n c e event and a more r e a l i s t i c s i t u a t i o n , t h e samples i n t h e f i e l d were not s t i r r e d and t h e f i n a l t a l l y was made a f t e r 16 weeks (25 A u g u s t ) . 83 Figure 3.1 The seed bank germination regimes, a) a p o r t i o n of the greenhouse experiment; b) the e n t i r e f i e l d experiment. 84 Two e x c e p t i o n s were made t o t h e method of c o u n t i n g g e r m i n a n t s . F i r s t / s p o r o p h y t e s o f t h e f e r n A t h y r i u m f i l i x - f e m i n a were sometimes so dense t h a t t h e i d e n t i f i c a t i o n o f i n d i v i d u a l p l a n t s was d i f f i c u l t , i f not i m p o s s i b l e . In such c a s e s , as c a r e f u l a count as p o s s i b l e was conducted, and t h e number of s p o r o p h y t e s r e c o r d e d was rounded t o t h e n e a r e s t t e n . The a c t u a l number o f s p o r o p h y t e s up t o and i n c l u d i n g 100 was r e c o r d e d . Because o f t h i s , t h e v a l u e s r e p o r t e d f o r A. f i l i x - f e m i n a a r e p r o b a b l y u n d e r e s t i m a t e s . Second, n a t i v e f o r e s t mosses were s i m p l y r e c o r d e d as " p r e s e n t " , and d a t a are r e p o r t e d as t h e f r e q u e n c y o f o c c u r r e n c e i n t h e subsamples. 3.2.1.4 Data a n a l y s i s D e s c r i p t i v e s t a t i s t i c a l a n a l y s e s were based on t h e number of p l o t s w i t h i n each v e g e t a t i o n X d i s t u r b a n c e c o m b i n a t i o n . The seed bank d a t a were a n a l y z e d w i t h r e s p e c t t o t h e v e g e t a t i o n u n i t s d i s t i n g u i s h e d d u r i n g t h e more o b j e c t i v e m u l t i v a r i a t e - v a r i a t e c l a s s i f i c a t i o n , not a c c o r d i n g t o t h e i n i t i a l , more s u b j e c t i v e v e g e t a t i o n t y p e s d e t e r m i n e d d u r i n g s a m p l i n g . 3.2.2 Seed g e r m i n a t i o n 3.2.2.1 Seed p r e p a r a t i o n and e x p e r i m e n t s Two seed g e r m i n a t i o n e x p e r i m e n t s were e s t a b l i s h e d i n a greenhouse u s i n g seeds of s e l e c t e d s p e c i e s . The f r u i t s of A l n u s  r u b r a , A n a p h a l i s m a r q a r i t a c e a , E p i l o b i u m a n q u s t i f o l i u m , G a u l t h e r i a s h a l l o n , H o l o d i s c u s d i s c o l o r , Rubus l e u c o d e r m i s , R. 85 p a r v i f l o r u s , and R. u r s i n u s were c o l l e c t e d a t t h e s t u d y s i t e s , a t th e U n i v e r s i t y o f B r i t i s h Columbia (UBC) R e s e a r c h F o r e s t , o r on the UBC campus i n t h e l a t e summer/early f a l l o f 1984. F l e s h y f r u i t s were macerated and washed r e p e a t e d l y , a l l o w i n g t h e p u l p and u n f i l l e d seeds t o f l o a t o f f . The seeds were t h e n a i r d r i e d . The pappus of A n a p h a l i s and coma o f E p i l o b i u m were removed by p a s s i n g t h e f r u i t s t h r o u g h a fine-mesh s i e v e . A l l s e e d s / f r u i t s were s t o r e d d ry u n t i l t h e y were p r e p a r e d f o r s t r a t i f i c a t i o n . T h i r t y seeds o f each s p e c i e s were counted out, p l a c e d i n p l a s t i c - w r a p p a c k e t s o f c o a r s e sand, m o i s t e n e d , and s t r a t i f i e d a t 1-3°C. Seeds o f R. l e u c o d e r m i s were a c i d s c a r i f i e d f o r 15 minutes i n c o n c e n t r a t e d s u l f u r i c a c i d (Schopmeyer 1974) p r i o r t o c o u n t i n g and s t r a t i f i c a t i o n . Seeds of t h e Rubus s p e c i e s , H. d i s c o l o r , A. m a r q a r i t a c e a and E. a n q u s t i f o l i u m were p r e p a r e d i n mid-January, and t h o s e o f A l n u s r u b r a and G. s h a l l o n i n e a r l y March. The l e n g t h o f t h e s t r a t i f i c a t i o n p e r i o d v a r i e d w i t h t h e date each experiment was e s t a b l i s h e d . M i n e r a l s o i l used i n t h e e x p e r i m e n t s , a B - h o r i z o n f i n e sandy loam, was c o l l e c t e d from s o i l e x c a v a t e d from a f o r e s t w i t h i n t h e UBC Endowment Lands. F o r e s t f l o o r m a t e r i a l was c o l l e c t e d from th e UBC R e s e a r c h F o r e s t , from an a p p r o x i m a t e l y 100 y e a r - o l d s t a n d dominated by Pseudotsuqa m e n z i e s i i and Tsuga h e t e r o p h y l l a . A t w o - f a c t o r experiment t e s t i n g t h e i n f l u e n c e o f depth o f b u r i a l and s u b s t r a t e on g e r m i n a t i o n was e s t a b l i s h e d on 26-28 A p r i l , 1985. Seeds of each s p e c i e s were b u r i e d a t f o u r depths (0, 0.5, 1.5, and 3.0 cm) i n f o r e s t f l o o r and m i n e r a l s o i l . Each 86 t r e a t m e n t c o m b i n a t i o n was r e p l i c a t e d f i v e t i m e s f o r each s p e c i e s . The r e p l i c a t e s were randomly a r r a n g e d on a greenhouse bench. G e r m i n a t i o n was r e c o r d e d weekly f o r 9 weeks. Maximum g e r m i n a t i o n d a t a (from t h e f i n a l t a l l y ) were a n a l y z e d . A t h r e e - f a c t o r experiment t e s t i n g t h e i n f l u e n c e o f shade, s u b s t r a t e and water on g e r m i n a t i o n was s e t up on 7-8 May, 1985. Four shade l e v e l s r e p r e s e n t i n g 100%, and a p p r o x i m a t e l y 50%, 20%, and 10% o f 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 (0%, 50%, 80% and 90% shade; measured w i t h a L i - C o r (190S) quantum sensor) p e n e t r a t i n g a greenhouse which had been t r e a t e d w i t h " K o o l Ray" ( C o n t i n e n t a l P r o d u c t s ) white-wash were e s t a b l i s h e d by s u s p e n d i n g 0, 3, 4, or 5 l a y e r s o f w h i t e shade c l o t h on 10 cm mesh w i r e frames 15 cm above t h e samples. Because o f t h e o r i e n t a t i o n o f th e room i n which t h e experiment was conducted, t h e r e was a g r a d i e n t i n t h e d u r a t i o n o f exposure t o d i r e c t s u n l i g h t a l o n g t h e greenhouse bench. R e p l i c a t e s o f t h i s experiment were t h e r e f o r e s e t up i n 5 b l o c k s a l o n g t h e greenhouse bench. W i t h i n each b l o c k , t h e r e p l i c a t e s were randomly a r r a n g e d . The white-wash d r a m a t i c a l l y reduced t h e amount of 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 t h a t p e n e t r a t e d t h e greenhouse. F u r t h e r m o r e , l i g h t q u a l i t y was not a s s e s s e d : f a r r e d l i g h t (750 nm), as w e l l as d a r k n e s s , can i n t e r f e r e w i t h g e r m i n a t i o n (Wesson and Wareing 1969; Grime 1979). Because o f t h e s e two r e a s o n s , t h e r e s u l t s from t h i s experiment cannot be e x t r a p o l a t e d t o f i e l d c o n d i t i o n s . 87 Two w a t e r i n g regimes ("wet"/ "dry") were e s t a b l i s h e d . A l l t r e a t m e n t s were t h o r o u g h l y watered when f i r s t s e t up, but d u r i n g d a i l y w a t e r i n g t h e r e a f t e r t h e "wet" t r e a t m e n t samples were g i v e n a p p r o x i m a t e l y t w i c e as much water as t h e " d r y " t r e a t m e n t samples. A f t e r e q u i l i b r a t i o n , t h e s o i l m o i s t u r e p e r c e n t a g e o f t h e m i n e r a l s o i l samples ranged between 43+2 t o 52±1% (by weight) f o r t h e "wet" regime samples ( b e f o r e and a f t e r w a t e r i n g , r e s p e c t i v e l y ) , and 19±1 t o 2 6±1% f o r t h e " d r y " regime samples. C o r r e s p o n d i n g v a l u e s f o r t h e f o r e s t f l o o r s u b s t r a t e were 546±25 t o 632±27% ("wet") and 383±28 t o 448±30% ("dry"). Each s p e c i e s X t r e a t m e n t c o m b i n a t i o n was r e p l i c a t e d f i v e t i m e s , e x c e p t f o r G a u l t h e r i a s h a l l o n f o r which some t r e a t m e n t c o m b i n a t i o n s had o n l y f o u r r e p l i c a t e s (an i n a d e q u a t e number o f seed p a c k e t s had been p r e p a r e d ) . G e r m i n a t i o n was r e c o r d e d weekly f o r 8 weeks. Some s e e d l i n g s , e s p e c i a l l y t h o s e o f A n a p h a l i s  m a r q a r i t a c e a , were g r a z e d by c o c k r o a c h e s . Because o f t h i s , maximum g e r m i n a t i o n d a t a ( i . e . , t h e maximum number o f s e e d l i n g s o b s e r v e d f o r a s p e c i e s i n each r e p l i c a t e o f a t r e a t m e n t c o m b i n a t i o n d u r i n g t h e 8 week e x p e r i m e n t a l p e r i o d ) were a n a l y z e d . 3.2.2.2 Data a n a l y s i s Data from each experiment were c o n v e r t e d t o " p e r c e n t o f maximum g e r m i n a t i o n " (number o f germinants i n t h e r e p l i c a t e d i v i d e d by t h e maximum number o f germ i n a n t s r e c o r d e d f o r t h a t s p e c i e s i n t h e e n t i r e e x p e r i m e n t ) . The d a t a can thus be more e a s i l y d i s c u s s e d . These d a t a were s u b s e q u e n t l y t r a n s f o r m e d , u s i n g t h e a r c s i n e t r a n s f o r m a t i o n which i s recommended f o r p e r c e n t 88 d a t a (Zar 1984). The d a t a were s t i l l not n o r m a l l y d i s t r i b u t e d f o l l o w i n g t r a n s f o r m a t i o n , however, and th u s v i o l a t e one o f t h e main assumptions o f a n a l y s i s o f v a r i a n c e . The B o n f e r r o n i p r o c e d u r e ( M i l l e r 1981; W i l k i n s o n 1986) was employed i n d e t e r m i n i n g t h e s i g n i f i c a n c e l e v e l s i n t h e a n a l y s i s o f v a r i a n c e of t h e a r c s i n e t r a n s f o r m e d d a t a . I n t h i s p r o c e d u r e , t h e l e v e l o f s i g n i f i c a n c e d e s i r e d ( a l p h a , e.g., .05) i s d i v i d e d by t h e number of comparisons (k, e.g., 5) t o be made. Al p h a / k (.05/5=.01) i s the n used as t h e c r i t i c a l v a l u e f o r each comparison. T h i s p r o c e d u r e reduces t h e chance of c o m m i t t i n g a Type I e r r o r , i . e . , t h e c a l l i n g o f a t r e a t m e n t e f f e c t s i g n i f i c a n t when i t i s a c t u a l l y n o t . N o n - p a r a m e t r i c methods are b e t t e r s u i t e d f o r a n a l y s i s o f th e s e d a t a , and t h e r e f o r e u n t r a n s f o r m e d p e r c e n t o f maximum g e r m i n a t i o n d a t a f o r each l e v e l o f depth, s u b s t r a t e , shade and water were t e s t e d f o r s i g n i f i c a n t d i f f e r e n c e s u s i n g W i l c o x o n ' s s i g n e d - r a n k t e s t (Zar 1984). The d a t a p r e s e n t e d i n graphs a re the b a c k - t r a n s f o r m e d v a l u e s , and are thu s i n t h e i r o r i g i n a l u n i t s . 3.3 R e s u l t s 3 . 3 . 1 The seed bank The d i s t r i b u t i o n o f the p l o t s among the v e g e t a t i o n u n i t s w hich were i d e n t i f i e d i n Chapter 2 i s shown i n Tab l e 3 . 1 . The P i n u s - Dicranum - A m e l a n c h i e r immature f o r e s t v e g e t a t i o n u n i t ( h e r e a f t e r r e f e r r e d t o as th e A m e l a n c h i e r u n i t , o r B) was l o c a t e d on r i d g e c r e s t s and upper s l o p e s w i t h a v e r y d r y t o dr y m o i s t u r e regime. The Pseudotsuga - H o l o d i s c u s v e g e t a t i o n u n i t (the 89 T a b l e 3.1 The d i s t r i b u t i o n o f seed bank sample p l o t s among t h e r e c o g n i z e d v e g e t a t i o n u n i t s a d j a c e n t t o and on t h e Cheekye Loop and M a l a s p i n a t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . F o r e s t v e g e t a t i o n u n i t B = A m e l a n c h i e r C = H o l o d i s c u s , D = K i n d b e r g i a , E = M y c e l i s , F = D r y o p t e r i s . S e r a i v e g e t a t i o n u n i t 1 = G a u l t h e r i a , 2 = P o l y t r i c h u m , 3 = Phleum, 4 = P t e r i d i u m , 5 = A t h y r i u m . F o r e s t v e g e t a t i o n u n i t s B C D E F Cheekye Loop 1 1 2 3 2 M a l a s p i n a 3 3 2 1 S e r a i v e g e t a t i o n u n i t s Low d i s t u r b a n c e : 1 2 3 4 5 Cheekye Loop 2 1 4 M a l a s p i n a 3 1 Hig h d i s t u r b a n c e : Cheekye Loop M a l a s p i n a 4 2 4 2 90 H o l o d i s c u s u n i t , C) was found on c r e s t s and upper s l o p e s w i t h a d r y s o i l m o i s t u r e regime. Pseudotsuqa - K i n d b e r q i a v e g e t a t i o n u n i t (the K i n d b e r q i a u n i t , D) was l o c a t e d on upper t o lower s l o p e s w i t h i n t e r m e d i a t e m o i s t u r e a v a i l a b i l i t y . Pseudotsuqa -M y c e l i s p l o t s (the M y c e l i s u n i t , E) were found on m i d - s l o p e s t o l e v e l a r e a s w i t h i n t e r m e d i a t e t o m o i s t s o i l s . A l n u s - D r y o p t e r i s p l o t s (the D r y o p t e r i s u n i t , F) were l o c a t e d on l o w e r s l o p e s t o d e p r e s s i o n s w i t h m o i s t t o wet s o i l s . Of t h e e a r l y s e r a i v e g e t a t i o n u n i t s l o c a t e d on t h e t r a n s m i s s i o n l i n e r i g h t s - o f - w a y , t h e P t e r i d i u m - G a u l t h e r i a -T h u i a u n i t ( G a u l t h e r i a , 1) was, i n g e n e r a l , found on low d i s t u r b a n c e (mean m i n e r a l s o i l exposure = 0%), c r e s t t o upper s l o p e , v e r y d r y t o d r y s i t e s . The P t e r i d i u m - G a u l t h e r i a -P o l y t r i c h u m v e g e t a t i o n u n i t ( P o l y t r i c h u m , 2) was m o d e r a t e l y d i s t u r b e d (mean m i n e r a l s o i l exposure = 2 6 % ) , and was l o c a t e d on c r e s t s t o m i d - s l o p e s w i t h a v e r y d r y t o i n t e r m e d i a t e m o i s t u r e regime. The Rubus - P t e r i d i u m - Phleum v e g e t a t i o n u n i t (Phleum, 3) was s e v e r e l y d i s t u r b e d (mean m i n e r a l s o i l exposure = 5 8 % ) , and was l o c a t e d on m i d - s l o p e t o l e v e l a r e a s w i t h d r y t o m o i s t s o i l s . Rubus - P t e r i d i u m - M y c e l i s v e g e t a t i o n u n i t p l o t s ( P t e r i d i u m , 4) were l e s s d i s t u r b e d (mean m i n e r a l s o i l exposure = 17%), and were l o c a t e d on m i d - s l o p e s t o d e p r e s s i o n s w i t h i n t e r m e d i a t e t o m o i s t s o i l s . The Rubus - A t h y r i u m p l o t s (Athyrium, 5) were s l i g h t l y d i s t u r b e d (mean m i n e r a l s o i l exposure = 15%), and were l o c a t e d on m i d - s l o p e s t o d e p r e s s i o n s w i t h m o i s t t o wet s o i l s . In t h e a n a l y s e s p r e s e n t e d below, t h e seed bank d a t a from t h e f o r e s t u n i t s A m e l a n c h i e r (B) and H o l o d i s c u s (C) were combined. 91 S i m i l a r l y , t h e d a t a f o r t h e low d i s t u r b a n c e G a u l t h e r i a (1) and P o l y t r i c h u m (2) p l o t s were combined, as were t h e d a t a f o r t h e h i g h d i s t u r b a n c e A t h y r i u m (5) and P t e r i d i u m (4) p l o t s . The combining o f d a t a , as d e s c r i b e d above, was c o n s i d e r e d t o be j u s t i f i a b l e : t h e f l o r i s t i c s i m i l a r i t y o f t h e p l o t s f o r which d a t a were combined was h i g h . Because t h e number of p l o t s o f each v e g e t a t i o n u n i t on each r i g h t - o f - w a y was not comparable, a s t a t i s t i c a l comparison o f t h e seed banks o f t h e two s i t e s was not a p p r o p r i a t e a l t h o u g h a q u a l i t a t i v e one was. The d a t a from t h e s i t e s a re combined f o r t h e purposes o f comparing t h e seed banks a s s o c i a t e d w i t h d i f f e r e n t v e g e t a t i o n t y p e s . 3.3.1.1 S p e c i e s and numbers of seeds A t o t a l o f 17,883 ger m i n a n t s r e p r e s e n t i n g 78 s p e c i e s , i n c l u d i n g 63 n a t i v e o r n a t u r a l i z e d t r e e , shrub, and herb s p e c i e s , 5 seeded agronomic g r a s s and legume s p e c i e s , 4 f e r n s , 1 h o r s e t a i l , and 5 mosses, emerged from t h e s o i l samples. (The term "seed" i s used t h r o u g h o u t t h i s c h a p t e r when r e f e r r i n g t o t h e p r o p a g u l e s o f angiosperms and gymnosperms: i t i s r e c o g n i z e d t h a t some of t h e p r o p a g u l e s are c o r r e c t l y termed f r u i t s o r spores.) Data on t h e t o t a l numbers of each s p e c i e s emerging from a l l (greenhouse and f i e l d ) samples w i t h i n each v e g e t a t i o n X d i s t u r b a n c e c o m b i n a t i o n are shown i n T a b l e 3.2. Of t h e 78 s p e c i e s , 51 were found a t b o t h s i t e s . The Cheekye Loop had 20 a d d i t i o n a l s p e c i e s , and M a l a s p i n a 7. Of t h e 20 a d d i t i o n a l s p e c i e s a t t h e Cheekye Loop, o n l y 1 s e e d l i n g emerged 92 T a b l e 3.2 T o t a l numbers o f germ i n a n t s ( e x c l u d i n g mosses) emerging from a l l samples o f f o r e s t , and low and h i g h d i s t u r b a n c e s e r a i s o i l s i n t h e greenhouse and f i e l d . Numbers i n i t a l i c s i n d i c a t e t h e pr e s e n c e o f t h a t s p e c i e s i n t h e v e g e t a t i o n o f t h e p l o t s from which t h e seed bank samples were t a k e n . C = Cheekye Loop s i t e o n l y , M = M a l a s p i n a s i t e o n l y , s = seeded, v = v e g e t a t i v e , C = H o l o d i s c u s , E = M y c e l i s , 1 = G a u l t h e r i a , 3 = Phleum, F o r e s t v e g e t a t i o n u n i t S e r a i v e g e t a t i o n u n i t D = K i n d b e r q i a , F = D r y o p t e r i s 2 = P o l y t r i c h u m , 4 = P t e r i d i u m . Forest Serai Disturbance Low Low High High Higl Vegetation Unit C D E F 2 4 2 3 4 (Number of plots) (5) (5) (5) (3) (6) (5) (6) (5) (7) Acer macrophvllum (M) 1 A q r o s t i s spp. 20 5 4 1 56 ' 239 96 14 92 A i r a praecox (M) 6 1 2 6 Alnus rubra 35 115 116 86 5 1 Anaphalis marqaritacea 7 21 22 41 4 298 11 2 70 A q u i l e q i a formosa (C) 2 Aruncus d i o i c a (C) 1 4 2 2 Athvrium f i l i x - f e m i n a 975 1877 1389 1110 332 587 14 58 233 Betula p a p v r i f e r a (C) 23 333 1005 38 24 71 11 3 Blechnum spicant 37 16 295 116 1 6 269 33 Capsella bursa-pastoris (M) 1 Carex spp. 3 1 71 33 2 328 1 73 Circaea a l p i n a (M,v) 18 Cirsium vulqare 1 22 1 C l a y t o n i a s i b i r i c a 8 2 1 Collomia heterophvlla (M) 8 14 1 Conyza canadensis 1 4 2 6 1 55 289 5 Cornus s e r i c e a (C) 1 Cor v d a l i s sempervirens (C) 1 Danthonia spic a t a 91 1 1 Deschampsia danthonioides 1 1 9 Epilobium anqustifolium (C) 2 1 Epilobium minutum 3 1 45 3 1 Epilobium watsonii 9 27 51 15 22 235 19 30 41 Eauisetum pratense (C,v) 13 Ericaceae (unidentified) (M) I Festuca rubra (s) 1 6 3 1 28 65 9 5 a F r a q a r i a v i r q i n i a n a 1 1 Galium t r i f l o r u m 28 32 4 64 17 231 G a u l t h e r i a s h a l l o n 88 22 23 14 134 18 4 5 G a u l t h e r i a s h a l l o n (v) 1 Gvmnocarpium d r v o p t e r i s (v) 3 3 Heuchera micrantha 19 1 Hieracium a l b l f l o r u m (C) 1 1 Holodiscus d i s c o l o r 15 1 16 3 2 1 Hypochoeris r a d i c a t a (C) 1 Juncus e n s i f o l i u s (C) 1 2 Juncus spp. 1 3 1 5 1 1 1 Lolium perenne (s) 9 1 11 4 2 4 Luzula spp. 2 20 5 1 7 2 6 58 Lycopus u n i f l o r u s (C) 1 31 (continued) 93 Table 3.2 (continued) Forest Serai Disturbance Low Low High High High Vegetation Unit C D E F 2 4 2 3 4 (Number of plots) (5) (5) (5) (3) (6) (5) (6) (5) (7) Mahonia nervosa (C) 1 Mimulus quttatus (M) 1 Mvcelis muralis 4 1 37 3 6 165 1 6 Oenanthe sarmentosa (C) 1 Phleum pratense (s) 6 4 7 1 10 14 58 21 Phvsocarpus capitatus (C) 1 Plantaqo malor (M) - 1 Poa spp. * 64 5 31 11 56 69 22 4 Populus t r i c h o c a r p a (C,v) 1 Pseudotsuqa menziesii 1 2 1 1 Pteridium aquilinum 109' 277 121 . 3 14 19 3 2 2 Rubus leucodermis 10 11 59 2 5 51 13 Rubus p a r v i f l o r u s 4 131 59 80 12 131 2 Rubus p a r v i f l o r u s (v) 1 Rubus s p e c t a b i l i s 8 10 2 1 1 Rubus ursinus 11 3 2 3 10 2 Sambucus racemosa 3 2 6 1 1 Scirpus microcarpus 1 1 3 Senecio s v l v a t i c u s 74 57 53 17 33 7 123 358 725 370 Sonchus oleraceus 3 3 5 1 2 37 5 19 Sperqularia rubra (C) 1 5 441 Spiraea d o u q l a s i i 22 4 3 7 5 1 11 S t e l l a r i a c r i s p a 3 5 4 1 134 Taraxacum o f f i c i n a l i s 1 Thula p l i c a t a (C) 5 2 2 1 1 T i a r e l l a t r i f o l i a t a (v) 20 T r i e n t a l i s l a t i f o l i a (v) 2 10 40 20 T r i f o l i u m spp. (s) 10 16 126 6 9 11 3 Trisetum cernuum 1 1 1 2 3 52 37 Tsuqa heterophylla 3 10 5 1 5 2 Tvoha l a t i f o l i a 1 1 Veronica americana (C) 1 Veronica sop. (C) 1 U n i d e n t i f i e d grasses 1 10 1 14 No. of taxa i n seed bank 39 37 41 34 40 42 21 26 45 No. of taxa i n vegetation 27 30 45 39 40 50 52 44 73 No. of seed bank taxa represented i n vegetation 11 9 20 19 26 28 17 19 34 % of vegetation taxa represented i n seed bank 40.7 30.0 44.4 48.7 65.0 56.0 32.7 43.2 46.6 % of seed bank taxa represented i n vegetation 28.2 24.3 48.8 55.9" 65.0 66.7 81.0 73.1 75.7 * a combination of Poa compressa (native/naturalized) and Poa  pratensis (seeded) 94 f o r 9 o f t h e s p e c i e s , and 9 o t h e r s p e c i e s were r e p r e s e n t e d by 15 or fewer s e e d l i n g s . B e t u l a p a p y r i f e r a and S p e r q u l a r i a r u b r a had more th a n 100 s e e d l i n g s . F i v e o f t h e 7 s p e c i e s d i s t i n c t i v e t o M a l a s p i n a were r e p r e s e n t e d by o n l y one s e e d l i n g , and t h e o t h e r 2 s p e c i e s were r e p r e s e n t e d by l e s s t h a n 20 s e e d l i n g s each. An average of 41.0%, 60.5%, and 40.8% of a l l t h e s p e c i e s p r e s e n t i n t h e v e g e t a t i o n were r e p r e s e n t e d i n t h e seed bank of t h e f o r e s t , low d i s t u r b a n c e and h i g h d i s t u r b a n c e p l o t s , r e s p e c t i v e l y . C o n v e r s e l y , 39.3%, 65.9%, and 76.6%, r e s p e c t i v e l y , o f a l l t h e seed bank t a x a were r e p r e s e n t e d i n t h e v e g e t a t i o n o f t h e p l o t s from which t h e seed bank samples were t a k e n . N i n e t e e n s p e c i e s which g e r m i n a t e d from s o i l samples were not found i n t h e v e g e t a t i o n o f any o f t h e seed bank sample p l o t s . Of t h e s e s p e c i e s , however, 12 were r e c o r d e d i n o t h e r p l o t s sampled f o r t h e purposes of v e g e t a t i o n c l a s s i f i c a t i o n , and t h e r e m a i n i n g 5 (not t h e u n i d e n t i f i e d e r i c a c e o u s s p e c i e s o r V e r o n i c a spp.) were obs e r v e d on or near t h e s t u d y s i t e s . F i v e s p e c i e s a r o s e o n l y v e g e t a t i v e l y , from r o o t fragments ( T i a r e l l a t r i f o l i a t a , and Populus t r i c h o c a r p a ) , rhizomes (Gvmnocarpium d r y o p t e r i s ) , and t u b e r s ( C i r c a e a a l p i n a , T r i e n t a l i s  l a t i f o l i a ) . Seven g r a s s s p e c i e s d i d not f l o w e r and were lumped t o g e t h e r as " u n i d e n t i f i e d g r a s s e s " . P l a n t s o f t h e genera T r i f o l i u m , Carex, L u z u l a , and Juncus (except Juncus e n s i f o l i u s ) were i d e n t i f i e d t o genus o n l y . The d a t a f o r two c o n g e n e r i c p a i r s , Poa compressa ( n a t i v e ) / P . p r a t e n s i s (seeded) and A g r o s t i s  s c a b r a ( n a t i v e ) / A . s t o l o n i f e r a ( n a t u r a l i z e d ) , are p r e s e n t e d under Poa spp. and A g r o s t i s spp., r e s p e c t i v e l y . 95 C o n t a m i n a t i o n o f t h e seed bank samples i n t h e e x p e r i m e n t a l f i e l d by weeds growing i n t h e f i e l d c o u l d not be p r e v e n t e d . P r e c a u t i o n s , i n c l u d i n g t h e c o n s t r u c t i o n o f a p l a s t i c mulch b o r d e r and b a r k m u l c h i n g o f t h e p a t h s between th e rows, were t a k e n but were not c o m p l e t e l y e f f e c t i v e . The i d e n t i f i c a t i o n o f s p e c i e s as c o n t a m i n a n t s was based on t h e i r p r e s e nce i n or near t h e e x p e r i m e n t a l f i e l d , and t h e absence o f t h o s e s p e c i e s i n t h e greenhouse samples. Two o f t h e c o n t a m i n a n t s were c o n g e n e r i c w i t h seed bank s p e c i e s , and c o u l d be i d e n t i f i e d i f a l l o w e d t o mature beyond t h e s e e d l i n g s t a g e . The b l a c k - t i p p e d b r a c t s o f S e n e c i o  v u l g a r i s d i s t i n g u i s h e d i t from S_. s y l v a t i c u s , and t h e m a t - l i k e h a b i t o f Poa annua i d e n t i f i e d i t as d i s t i n c t from P. compressa/P. p r a t e n s i s . The abundance of t h o s e s p e c i e s which had an e q u i v a l e n t of a t l e a s t 100 g e r m i n a n t s p e r square meter i n one or more v e g e t a t i o n t y p e s and which were p r e s e n t a t b o t h s t u d y s i t e s , was a n a l y z e d i n d e t a i l . The second r e q u i r e m e n t e l i m i n a t e d two s p e c i e s which were e x c l u s i v e t o t h e Cheekye Loop; B e t u l a p a p y r i f e r a and S p e r g u l a r i a  r u b r a . B e t u l a p a p y r i f e r a was found i n 100% (1021±536 ( s t a n d a r d e r r o r ) seeds/m 2), 86% (80±34 seeds/m 2), and 44% (11±8 seeds/m 2) of t h e f o r e s t e d , low, and h i g h d i s t u r b a n c e seed bank samples, r e s p e c t i v e l y , a t t h e Cheekye Loop. S p e r g u l a r i a r u b r a was found i n 0%, 14% (7-7 seeds/m 2), and 22% (357-355 seeds/m 2) o f t h e f o r e s t e d , low, and h i g h d i s t u r b a n c e seed bank samples, r e s p e c t i v e l y . T a b l e 3.3 c o n t r a s t s t h e c o n s t a n c y of t h e 15 s p e c i e s meeting th e above c r i t e r i a a t t h e s t u d y s i t e s . Nine o f t h e s p e c i e s were more common a t t h e Cheekye Loop, 4 a t M a l a s p i n a , and 2 (Athyrium  f i l i x - f e m i n a , G a u l t h e r i a s h a l l o n ) were e s s e n t i a l l y e q u a l l y common at t h e two s i t e s . The d i f f e r e n c e s i n c o n s t a n c y o f t h e s p e c i e s between f o r e s t , and low and h i g h d i s t u r b a n c e samples p r o b a b l y r e f l e c t s d i s p e r s a l d i s t a n c e (Alnus r u b r a ) , s u b s t r a t e (G. s h a l l o n , Rubus p a r v i f l o r u s , A. f i l i x - f e m i n a , Galium t r i f l o r u m ) , and p r o x i m i t y t o d i s t u r b e d a r e a s ( A g r o s t i s spp. and F e s t u c a r u b r a ) . Summary d a t a from t h e f o r e s t e d and low d i s t u r b a n c e p l o t s (Table 3.4) i n d i c a t e t h a t t h e g r e a t e s t number o f seeds was p r e s e n t i n t h e f o r e s t f l o o r l a y e r , and t h a t t h e number o f seeds d e c r e a s e d w i t h i n c r e a s i n g d e p t h . F u r t h e r m o r e , t h e c o n s t a n c y of g e r m i n a b l e seeds and sp o r e s i n d i c a t e s t h a t some s p e c i e s , p a r t i c u l a r l y A t h y r i u m f i l i x - f e m i n a , G a u l t h e r i a s h a l l o n and Senec i o s y l v a t i c u s , were w i d e l y d i s t r i b u t e d , though a t d i f f e r e n t d e n s i t i e s . A l n u s r u b r a , A t h y r i u m f i l i x - f e m i n a , and P t e r i d i u m  a q u i l i n u m p r o p a g u l e s were more common i n t h e f o r e s t . Rubus  p a r v i f l o r u s , M y c e l i s m u r a l i s and Galium t r i f l o r u m were found p r e d o m i n a n t l y on f o r e s t f l o o r m a t e r i a l s , and so were more common i n f o r e s t e d and low d i s t u r b a n c e v e g e t a t i o n u n i t s . The seed banks from d i s t u r b e d s i t e s g e n e r a l l y c o n t a i n e d fewer g e r m i n a b l e t r e e seeds and f e r n s p o r e s , but seeds o f e a r l y s u c c e s s i o n a l herbaceous s p e c i e s ( A g r o s t i s spp., A n a p h a l i s m a r q a r i t a c e a , Conyza  c a n a d e n s i s , E p i l o b i u m w a t s o n i i , M y c e l i s m u r a l i s , S e n e c i o  s y l v a t i c u s ) , and seeded agronomics ( F e s t u c a rubra) were more numerous. A t h y r i u m f i l i x - f e m i n a and A g r o s t i s spp. (an average o f 67% at t h e two stu d y s i t e s ) , E. w a t s o n i i (50%) and S.. s y l v a t i c u s (83%) had t h e h i g h e s t c o n s t a n c y i n t h e h i g h d i s t u r b a n c e samples. 97 Ta b l e 3.3 P e r c e n t c o n s t a n c y o f seed bank s p e c i e s i n t h e f o r e s t e d , low and h i g h d i s t u r b a n c e p l o t s a t t h e two s t u d y s i t e s . Only t h o s e s p e c i e s h a v i n g a t l e a s t 100 seeds p e r square meter i n one v e g e t a t i o n t y p e and p r e s e n t a t b o t h s t u d y s i t e s a r e i n c l u d e d . Cheekye Loop M a l a s p i n a F o r e s t Low H i g h F o r e s t Low Hig h (Number of p l o t s ) (9) (7) (9) (9) (4) (9) A g r o s t i s spp. 44 86 78 11 75 56 A l n u s r u b r a 100 29 11 56 0 0 A n a p h a l i s m a r g a r i t a c e a 78 57 33 56 0 33 A t h y r i u m f i l i x - f e m i n a 100 • 100 78 100 100 56 Blechnum s p i c a n t 67 0 22 67 50 11 Carex spp. 11 29 56 67 25 0 Conyza c a n a d e n s i s 33 43 11 22 0 22 E p i l o b i u m w a t s o n i i 78 86 44 78 25 56 F e s t u c a r u b r a 22 71 33 22 75 11 Galium t r i f l o r u m 33 43 11 33 50 22 G a u l t h e r i a s h a l l o n 89 86 33 89 100 22 M y c e l i s m u r a l i s 78 43 . 11 11 25 11 P t e r i d i u m a q u i l i n u m 90 71 22 33 0 11 Rubus p a r v i f l o r u s 78 71 11 78 25 0 S e n e c i o s v l v a t i c u s 67 71 67 100 100 100 Table 3.4 Mean number of seeds per square meter ± standard error and constancy (%) of the 15 major seed bank species among the s o i l layers sampled i n the forested, low, and high disturbance p l o t s . Vegetation (n) Forest (18) Low disturbance (11) High (18) Forest Mineral s o i l Mineral s o i l Forest Mineral s o i l Mineral s o i l S o i l l a y e r Floor 0-5 cm 5-10 cm Floor 0-5 cm 0-5 cm Aq r o s t i s spp. 9 ± 6 (28) 1 ± 1 (6) 0 147 ± 112 (82) 13 ± 10 (22) 68 ± 25 (67) Alnus rubra 106 ± 28 (78) 5 ± 2 (33) 3 ± 2 (11) 1 + 1 (9) 3 ± 3 (6) 1 ± 1 (6) Anaphalis marqaritacea 33 ± 15 (56) 1 + 1 (6) 2 + 1 (17) 139 ± 106 (36) 2 + 2 (6) 32 ± 20 (33) Athvrium f i l i x - f e m i n a 2001 ± 300 (100) 734 ± 135 (100) 238 ± 72 (72) 526 ± 127 (91) 309 ± 197 (44) 169 ± 71 (67) Blechnum spicant 110 ± 52 (56) 124 ± 105 (33) 24 ± 14 (28) 4 ± 3 (15) 3 ± 3 (6) 168 ± 149 (17) Carex spp. 24 ± 13 (28) 10 ± 6 (22) 2 ± 1 (18) 215 ± 210 (27) 4 ± 4 (6) 27 ± 21 (28) Conyza canadensis 3 ± 2 (17) . 1 ± 1 (6) 1 + 1 (6) 31 ± 23 (27) 3 ± 3 (6) 99 ± 97 (17) Epilobium watsonii 30 ± 8 (22) 2 ± 1 (11) 2 ± 1 (11) 107 ± 61 (64) 8 ± 4 (22) 32 ± 11 (50) Festuca rubra 5 ± 3 (17) 1 ± 1 (6) 0 68 ± 46 (64) 4 ± 2 (17) 5 ± 3 (22) Galium t r i f l o r u m 16 ± 8 (33) 3 ± 2 (11) 1 + 1 (6) 52 ± 43 (45) 1 ± 1 (6) 80 ± 73 (17) Gault h e r i a s h a l l o n 48 ± 10 (89) 12 ± 5 (44) 5 ± 3 (22) 114 ± 53 (91) 10 ± 5 (22) 3 ± 1 (28) Mvcelis muralis 11 + 6 (33) 3 ± 1 (22) 0 101 ± 68 (36) 3 ± 2 (11) 2 ± 2 (11) Pteridium aouilinum 239 + 112 (50) 35 ± 16 (50) 9 + 5 (33) 20 ± 8 (45) 10 ± 6 (17) 4 ± 2 (17) Rubus p a r v i f l o r u s 50 ± 25 (55) 27 ± 13 (55) 10 ± 5 (28) 44 ± 22 (45) 16 ± 9 (22) 1 ± 1 (6) Senecio s y l v a t i c u s 44 ± 11 (78) 4 ± 1 (33) 1 ± 1 (6) 201 ± 108 (82) 23 ± 18 (33) 348 ± 121 (83) CO 99 The d i s t r i b u t i o n s o f t h e 15 major s p e c i e s , w i t h r e s p e c t t o v e g e t a t i o n u n i t , degree o f d i s t u r b a n c e , and s a m p l i n g l a y e r , a r e p r e s e n t e d i n T a b l e 3.5. Among t h e f o r e s t e d v e g e t a t i o n u n i t s , t h e dry H o l o d i s c u s v e g e t a t i o n u n i t had t h e l o w e s t t o t a l d e n s i t y of g erminants p e r square meter (2552 v s . 4810 i n t h e K i n d b e r g i a u n i t , 4128 i n t h e M v c e l i s u n i t , and 4753 i n t h e A t h y r i u m u n i t ) , and by s p e c i e s w i t h t h e e x c e p t i o n o f A g r o s t i s spp. ( p r o b a b l y A. s c a b r a ) , G a u l t h e r i a s h a l l o n and S e n e c i o s y l v a t i c u s . W i t h few e x c e p t i o n s , t h e number o f g e r m i n a n t s d e c r e a s e d w i t h i n c r e a s i n g sample depth. S i m i l a r p a t t e r n s were e v i d e n t i n t h e low d i s t u r b a n c e p l o t s (1214 seeds p e r square meter i n t h e P o l y t r i c h u m u n i t v e r s u s 3338 i n t h e P t e r i d i u m u n i t ) , e x c e p t f o r G a u l t h e r i a  s h a l l o n . S i m i l a r l y , h i g h d i s t u r b a n c e P o l y t r i c h u m u n i t p l o t s had t h e fewest seeds p e r square meter o v e r a l l (520, v e r s u s 1540 i n t h e Phleum, and 1124 i n t h e P t e r i d i u m u n i t ) , and by s p e c i e s , w i t h t h e e x c e p t i o n o f A g r o s t i s spp. ( p r o b a b l y A. s t o l o n i f e r a ) . 3.3.1.2 F i e l d v e r s u s greenhouse g e r m i n a t i o n A d d i t i o n a l g e r m i n a t i o n o c c u r r e d i n 38% (568 s e e d l i n g s ) , 16% (169 s e e d l i n g s ) , and 8% (68 s e e d l i n g s ) o f t h e greenhouse s o i l samples a f t e r t h e 28 August, 27 September, and 27 October s t i r r i n g s , r e s p e c t i v e l y . The d i f f e r e n c e s i n s e e d l i n g emergence between t h e two g e r m i n a t i o n regimes may be due t o 1) t h e d i f f e r e n t t e m p e r a t u r e , m o i s t u r e , o r i n s o l a t i o n regimes i n t h e f i e l d v e r s u s t h e greenhouse; 2) e a r l i e r t e r m i n a t i o n o f t h e f i e l d e x p e r i m e n t ; 3) t h e l a c k o f s t i r r i n g o f t h e f i e l d samples; o r a c o m b i n a t i o n o f t h e s e t h r e e f a c t o r s . Table 3.5 Density (mean ± standard error per square metre) of the 15 major seed bank species among the depths sampled in each of the forest, low, and high disturbance vegetation units. Numbers in i t a l i c s indicate the presence of that species i n the vegetation of the plots from which the seed bank samples were taken. Forest vegetation unit C = Holodiscus, D = Kindberqia, E = Mycelis, F = Dryopteris. Serai vegetation unit 1 = Gaultheria, 2 = Polystichum, 3 = Phleum, 4 = Pteridium. Forest (undisturbed) Low disturbance High disturbance C D E F 2 4 2 3 4 (n) (5) (5) (5) (3) (6) (5) (6) (5) (7) Forest f l o o r A q r o s t i s spp. 28 ± 19 4 ± 4 3 + 3 53 ± 28 260 + 250 Alnus rubra 38 ± 22 134 ± 79 116 ± 61 153 ± 24 2 + 2 Anaphalis maraaritacea 10 + 5 24 ± 13 32 ± 18 87 ± 87 5 ± 5 300 ± 224 Athyrium f i l i x - f e m i n a 1570 ± 463 2376 ± 682 1824 ± 449 2390 ± 1134 463 ± 119 602 ± 255 Blechnum spicant 38 ± 20 18 ± 18 150 ± 135 31 7 ± 203 2 ± 2 6 ± 6 Carex spp. 2 ± 2 56 ± 37 47 ± 47 2 ± 2 470 ± 460 Conyza canadensis 2 ± 2 2 ± 2 13 ± 13 68 ± 48 Epilobium watsonii 8 ± 4 36 ± 12 50 ± 24 23 ± 7 8 ± 5 226 ± 119 Festuca rubra 2 ± 2 12 ± 12 4 ± 4 32 ± 16 112 ± 102 Galium t r i f l o r u m 16 ± 6 67 ± 38 3 ± 2 110 ± 93 G a u l t h e r i a shallon 88 ± 19 28 ± 18 36 ± 14 37 + 18 185 ± 89 28 ± 9 Mycelis muralis 2 ± 2 2 ± 2 32 ± 19 7 ± 7 2 ± 2 220 ± 138 Pteridium acuilinum 200 ± 117 4 68 ± 380 188 ± 105 10 ± 10 20 ± 9 20 ± 15 Rubus p a r v i f l o r u s 92 ± 75 58 ± 51 50 ± 30 3 ± 3 92 ± 41 Senecio s y l v a t i c u s 80 ± 29 34 ± 16 38 ± 14 10 ± 6 262 ± 196 128 ± 64 Subtotal 2066 ± 440 3230 ± 954 2602 ± 485 3213 ± 1351 1042 ± 274 2642 ± 805 (continued) Table 3 . 5 (continued) Forest (undisturbed) Low disturbance High disturbance (n) C (5) D (5) E (5) F (3) 2 (6) 4 (5) 2 (6) 3 (5) 4 (7) Mineral s o i l 0-5 cm A q r o s t i s spp. 2 ± 2 5 + 2 22 ± 22 105 ± 59 16 ± 8 74 ± 38 Alnus rubra 2 ± 2 4 ± 2 2 ± 2 17 ± 9 5 ± 5 1 ± 1 Anaphalis marqaritacea 3 ± 3 4 ± 4 15 ± 13 4 ± 4 66 ± 50 Athyrium f i l i x - f e m i n a 318 ± 135 1162 ± 333 724 ± 297 730 ± 255 90 ± 71 572 ± 416 23 ± 14 116 ± 39 333 ± 169 Blechnum spicant 18 ± 18 14 ± 14 390 ± 378 40 ± 20 6 ± 6 538 ± 538 47 ± 45 Carex spp. 2 ± 2 30 ± 20 7 + 7 fi ± 8 2 ± 2 67 ± 51 Conyza canadensis 4 ± 4 6 ± 6 350 ± 350 4 ± 3 Epilobium watsonii 4 ± 4 2 ± 2 2 + 2 16 ± 8 17 + 13 22 ± 20 51 ± 21 Festuca rubra 2 ± 2 3 ± 3 4 ± 2 8 + 4 6 ± 6 Galium t r i f l o r u m a ± 8 3 ± 3 2 + 2 22 ± 22 190 + 188 G a u l t h e r i a s h a l l o n 34 ± 14 4 ± 2 2 ± 2 7 ± 3 7 + 8 2 ± 2 5 + 2 6 ± 4 Mycelis muralis 8 ± 4 3 ± 3 6 ± 4 6 ± 4 Pteridium aquilinum 12 ± 4 80 ± 46 34 ± 29 3 + 3 18 ± 11 5 ± 5 4 ± 4 3 ± 3 Rubus p a r v i f l o r u s 4 ± 2 60 ± 43 4 ± 2 47 ± 24 5 ± 5 30 ± 19 1 + 1 Senecio s y l v a t i c u s 6 ± 2 2 ± 2 2 ± 2 7 ± 7 40 + 32 2 ± 2 340 + 262 4 62 ± 265 274 ± 148 Subtotal 398 ± 161 1334 ± 377 1208 ± 582 863 ± 278 172 ± 89 696 ± 401 520 ± 312 1540 ± 461 1124 ± 339 Mineral s o i l 5-10 cm Alnus rubra 4 ± 4 10 ± 10 Anaohalis marqaritacea 6 ± 4 3 ± 3 Athyrium f i l i x - f e m i n a 62 ± 45 216 ± 143 230 ± 133 580 ± 206 Blechnum spicant 18 ± 16 50 ± 50 30 ± 21 Carex spp. 2 + 2 2 ± 2 3 ± 3 Conyza canadensis 2 ± 2 Epilobium watsonii 2 ± 2 7 + 7 Galium t r i f l o r u m 4 ± 4 G a u l t h e r i a s h a l l o n 12 ± 12 2 + 2 4 ± 2 Pteridium aquilinum 6 ± 4 6 ± 4 20 ± 18 Rubus p a r v i f l o r u s 4 ± 2 ± 6 43 ± 26 Senecio s y l v a t i c u s 4 ± 4 Subtotal 98 ± 57 245 ± 151 318 ± 162 677 ± 187 102 Two s p e c i e s , E p i l o b i u m minutum, and Heuchera m i c r a n t h a g e r m i n a t e d i n t h e greenhouse but not i n t h e f i e l d . S e e d l i n g s o f t h e s e s p e c i e s d i d not emerge u n t i l a f t e r t h e f i e l d e xperiment had been t e r m i n a t e d , however, and t h u s t h e i r absence from t h e f i e l d samples can not be s o l e l y a t t r i b u t e d t o u n f a v o r a b l e g e r m i n a t i o n c o n d i t i o n s i n t h e f i e l d . The t h r e e f e r n s p e c i e s (Athyrium f i l i x - f e m i n a , Blechnum  s p i c a n t , and P t e r i d i u m a q u i l i n u m ) were abundant i n t h e greenhouse samples but were absent from t h e f i e l d . The c o n s t a n c y , or f r e q u e n c y o f o c c u r r e n c e , o f t h e mosses P o l y t r i c h u m i u n i p e r i n u m and P. p i l i f e r u m was h i g h e r i n t h e d r i e r v e g e t a t i o n u n i t s ( H o l o d i s c u s (C), P o l y t r i c h u m ( 2 ) ) . The c o n s t a n c y o f a l l mosses was lower i n t h e f i e l d t h a n i n t h e greenhouse (Table 3 . 6 ) , but P. i u n i p e r i n u m and P. p i l i f e r u m , e a r l y s u c c e s s i o n a l moss s p e c i e s o f t e n found on r e c e n t l y d i s t u r b e d s i t e s , o c c u r r e d a t a much h i g h e r f r e q u e n c y i n t h e f i e l d t h a n t h e o t h e r moss s p e c i e s . A t r i c h u m s e l w y n i i , a n o t h e r e a r l y s u c c e s s i o n a l moss s p e c i e s , g e r m i n a t e d p r e d o m i n a n t l y i n samples from th e h i g h d i s t u r b a n c e p l o t s , but o n l y i n t h e greenhouse. A comparison, u s i n g W i l c o x o n ' s s i g n e d - r a n k t e s t , o f t h e numbers of g e r m i n a n t s of major seed bank s p e c i e s ( i n c l u d i n g B e t u l a p a p y r i f e r a ) emerging under t h e two regimes i s shown i n T a b l e 3 . 7 . The s t a t i s t i c a l l y not s i g n i f i c a n t but h i g h e r g e r m i n a t i o n o f S e n e c i o s y l v a t i c u s i n t h e f i e l d c o u l d i n p a r t be due t o c o n t a m i n a t i o n by S_. v u l g a r i s which was not d e t e c t e d . G e r m i n a t i o n o f E p i l o b i u m w a t s o n i i , M y c e l i s m u r a l i s , Rubus Table 3 . 6 Constancy (%) of moss species i n samples of immature forest s o i l s , and low and high disturbance early serai s o i l s , as observed under the greenhouse and f i e l d (in parentheses) germination regimes. Polytrichum pi l i f e r u m emerged from the Cheekye Loop samples only. Forest vegetation unit C = Holodiscus, D = Kindbergia, E = Mycelis, F = Dryopteris. Serai vegetation unit 1 = Gaultheria, 2 = Polystichum, 3 = Phleum, 4 = Pteridium. Forest Low High C D E F 2 4 2 3 4 (n) (5) (5) (5) (3) (6) (5) (6) (5) (7) Atrichum selwynii 2 6 16 14 Kindberqia oreqana 5 1(1) 3 2 Plaqiomnium sp. 3 16(1) 9 6 Polytrichum iuniperinum 36(8) 23(5) 11 20 83(35) 22(6) 63 (10) 52 (20) 23(11) Polytrichum p i l i f e r u m 7(7) 17(7) 104 Ta b l e 3.7 Comparison o f g e r m i n a t i o n , under greenhouse and f i e l d r egimes, o f major seed bank s p e c i e s . Mean ± s t a n d a r d e r r o r o f f i e l d g e r m i n a t i o n as a p e r c e n t o f greenhouse g e r m i n a t i o n , and W i l c o x o n ' s s i g n e d - r a n k t e s t . F i e l d g e r m i n a t i o n W i l c o x o n ' s as % o f s i g n e d - r a n k greenhouse g e r m i n a t i o n n t e s t A c r r o s t i s SPP. 89 ± 12 18 A l n u s r u b r a 73 ± 10 11 * A n a p h a l i s m a r q a r i t a c e a 62 ± 11 17 * B e t u l a p a p v r i f e r a 60 ± 6 14 * * * Carex spp. 59 ± 7 6 * Convza c a n a d e n s i s 64 ± 11 8 E p i l o b i u m w a t s o n i i 105 ± 23 18 ns F e s t u c a r u b r a 89 ± 32 8 ns Galium t r i f l o r u m 59 ± 12 10 * G a u l t h e r i a s h a l l o n 45 ± 10 16 * * M y c e l i s m u r a l i s 111 ± 29 9 ns Rubus p a r v i f l o r u s 96 ± 12 15 ns Sen e c i o s y l v a t i c u s 142 ± 19 38 ns ns = not s i g n i f i c a n t , * = .05 > P > .01, ** = .01 > p > .001, *** = .001 > p. 105 p a r v i f l o r u s , and F e s t u c a r u b r a was e f f e c t e d l i t t l e by t h e regime. A s i g n i f i c a n t r e d u c t i o n i n g e r m i n a t i o n under f i e l d c o n d i t i o n s was ob s e r v e d f o r t h e woody s p e c i e s A l n u s r u b r a , B e t u l a p a p y r i f e r a , and G a u l t h e r i a s h a l l o n , and t h e herbaceous s p e c i e s A g r o s t i s spp., A n a p h a l i s m a r g a r i t a c e a , Carex spp., Conyza c a n a d e n s i s , and Galium  t r i f l o r u m . 3.3.2 Seed g e r m i n a t i o n e x p e r i m e n t s R e s u l t s from t h e a n a l y s i s o f v a r i a n c e o f t h e a r c s i n e t r a n s f o r m e d p e r c e n t g e r m i n a t i o n d a t a , and W i l c o x o n ' s s i g n e d - r a n k t e s t o f u n t r a n s f o r m e d d a t a from t h e depth experiment a re p r e s e n t e d i n Ta b l e 3.8. Depth s i g n i f i c a n t l y a f f e c t e d g e r m i n a t i o n f o r a l l s p e c i e s (Table 3 .8a) . The p a t t e r n o f i n f l u e n c e v a r i e d w i t h s p e c i e s , however, as shown i n Ta b l e 3.8b and F i g u r e 3.2. The ANOVA and W i l c o x o n r e s u l t s f o r t h e s i g n i f i c a n c e o f t h e i n f l u e n c e o f s u b s t r a t e on g e r m i n a t i o n a re s i m i l a r . G e r m i n a t i o n of E p i l o b i u m a n g u s t i f o l i u m and G a u l t h e r i a s h a l l o n was g r e a t e r o n / i n t h e f o r e s t f l o o r s u b s t r a t e . The Rubus s p e c i e s show a tendency towards g r e a t e r g e r m i n a t i o n o n / i n t h e m i n e r a l s o i l s u b s t r a t e , a l t h o u g h i t i s s i g n i f i c a n t f o r o n l y Rubus p a r v i f l o r u s and R. u r s i n u s . G e r m i n a t i o n o f A l n u s r u b r a , A n a p h a l i s m a r g a r i t a c e a , E. a n g u s t i f o l i u m , G. s h a l l o n and H o l o d i s c u s d i s c o l o r a t 0.5 cm i n f o r e s t f l o o r was c o n s i s t e n t l y g r e a t e r t h a n i n m i n e r a l s o i l , p r o b a b l y r e f l e c t i n g t h e deeper p e n e t r a t i o n o f l i g h t i n t o t h e porous f o r e s t f l o o r m a t e r i a l . S i g n i f i c a n t i n t e r a c t i o n s between 106 Table 3.8 Analysis of the depth X substrate germination experiment, a) analysis of variance; b) Wilcoxon's signed-rank t e s t . FF = forest f l o o r ; MS = mineral s o i l . a) ANOVA Species Depth Substrate D X , (D) (S) Alnus rubra * * * ns ns Anaphalis marqaritacea *** ns * * * Epilobium a n q u s t i f o l i u m * ** ** * * ** Ga u l t h e r i a s h a l l o n • ** * ns Holodiscus d i s c o l o r *** ns * ** Rubus leucodermis *** ns ns Rubus p a r v i f l o r u s * ** * * * ** Rubus ursinus *** ** * ** * b) Wilcoxon's signed-rank t e s t DEPTH SUBS Species 0 cm: 0. 5cm: 1.5cm: MS: 0 .5 cm 1. 5cm 3.0cm 1. 5cm 3. 0cm 3. 0cm FF Alnus rubra * * ** * * ns ns Anaphalis marqaritacea * * * * * * ns ns Epilobium a n q u s t i f o l i u m * * * * * * * ns * G a u l t h e r i a s h a l l o n * * * * * * ns • Holodiscus d i s c o l o r * * * * ns ns ns ns Rubus leucodermis ns ns • * ns * ns ns Rubus p a r v i f l o r u s ns * * * * ns ns * * * Rubus ursinus ns ns * * ns * * * * ns = not s i g n i f i c a n t , * = .05 > p > .01, ** = .01> p > .001, *** = .001 > p. 107 F i g u r e 3.2 Mean and s t a n d a r d e r r o r o f back t r a n s f o r m e d g e r m i n a t i o n d a t a under each depth X s u b s t r a t e t r e a t m e n t c o m b i n a t i o n f o r each s p e c i e s . V a l u e s are o f f s e t t o m i n i m i z e o v e r l a p o f s t a n d a r d e r r o r b a r s . FF = f o r e s t f l o o r , MS = m i n e r a l s o i l . 108 » FF o MS DEPTH (cm) depth and s u b s t r a t e were d e t e c t e d f o r f i v e s p e c i e s (A. m a r q a r i t a c e a , E. a n q u s t i f o l i u m , H. d i s c o l o r , R. p a r v i f l o r u s and R. u r s i n u s ) and may r e f l e c t a n e g a t i v e c o r r e l a t i o n between l i g h t p e n e t r a t i o n i n t o , and m o i s t u r e c o n d u c t i o n by, t h e f o r e s t f l o o r and m i n e r a l s o i l g e r m i n a t i o n s u b s t r a t e s . Shade l e v e l e f f e c t s were s i g n i f i c a n t f o r o n l y t h r e e s p e c i e s (Table 3 .9 , F i g u r e 3 . 3 ) . F o r A. r u b r a , p e r c e n t g e r m i n a t i o n was h i g h e r under 90% shade t h a n under t h e o t h e r shade l e v e l s . G e r m i n a t i o n was b e t t e r under t h e 50 and 80% shade l e v e l s t h a n under 0% f o r E. a n q u s t i f o l i u m . F o r H. d i s c o l o r , p e r c e n t g e r m i n a t i o n was h i g h e r under a l l shaded t r e a t m e n t s t h a n under t h e unshaded t r e a t m e n t . The s i g n i f i c a n c e o f s u b s t r a t e was s p e c i e s - s p e c i f i c , and ANOVA and W i l c o x o n ' s t e s t agreed except i n t h e case o f E. a n q u s t i f o l i u m , f o r which ANOVA d e t e c 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 between t h e g e r m i n a t i o n r a t e s on t h e two s u b s t r a t e s w h i l e w i l c o x o n ' s t e s t d e t e c t e d a s i g n i f i c a n t d i f f e r e n c e a t p<.05. F o r a l l s p e c i e s f o r which a s i g n i f i c a n t d i f f e r e n c e was i n d i c a t e d by Wi l c o x o n ' s t e s t , g e r m i n a t i o n was h i g h e r on m i n e r a l s o i l . Water regime s i g n i f i c a n t l y a f f e c t e d (p<.001) t h e g e r m i n a t i o n o f a l l s p e c i e s u s i n g b o t h ANOVA and W i l c o x o n ' s t e s t , g e r m i n a t i o n b e i n g g r e a t e r i n t h e "wet" t r e a t m e n t . F o r Rubus u r s i n u s , i n t e r a c t i o n s between shade and s u b s t r a t e , s u b s t r a t e and water, and shade, s u b s t r a t e and water, were s i g n i f i c a n t . The o n l y o t h e r s i g n i f i c a n t i n t e r a c t i o n was between s u b s t r a t e and water f o r R. l e u c o d e r m i s . Table 3.9 Analysis of the shade X substrate X water germination experiment, a) analysis of variance; b) Wilcoxon's signed-rank t e s t . FF = forest f l o o r ; MS = mineral s o i l . a) ANOVA Species Block Shade Substrate Water Sh X Su Sh X W Su X W Sh X Si (Sh) (Su) (W) Alnus rubra ns *** ns ** * ns ns ns ns AnaDhalis maraaritacea ns ns *** ** * ns ns ns ns Epilobium anqustifolium ns ns * * * ns ns ns ns Gaultheria s h a l l o n ns ns ns * * * ns ns ns ns Holodiscus d i s c o l o r ns * ns * * * ns ns ns ns Rubus leucodermis ns ns ** * * * ns ns * ns Rubus p a r v i f l o r u s ns ns * * * * ns ns ns ns Rubus ursinus ns ns *** * * * * ns * *** b) Wilcoxon's signed-rank test SHADE SUBS WATER 0%: 50%: 80%: MS: Wet: Species 50% 80% 90% 80% 90% 90% FF Dry Alnus rubra ns ns * * * ns ** * * ns * * * Anaphalis marcaritacea * ns ns ns ns ns * * * *** Epilobium a n a u s t i f o l i u m * * * * * ns ns ns ns * *** Gaultheria shallon ns ns ns ns ns ns ns * * * Holodiscus d i s c o l o r * * * * * ns ns ns ns * * * Rubus leucodermis ns ns ns ns ns ns • * *** Rubus p a r v i f l o r u s ns ns * ns * * * * * * * Rubus ursinus ns ns ns ns ns ns * * * * ns = not s i g n i f i c a n t , * = .05> p > .01, ** = .01> p > .001, *** = .001> p. I l l F i g u r e 3.3 Mean and s t a n d a r d e r r o r o f b a c k - t r a n s f o r m e d g e r m i n a t i o n d a t a under each shade X water X s u b s t r a t e t r e a t m e n t c o m b i n a t i o n f o r each s p e c i e s . V a l u e s are o f f s e t t o m i n i m i z e o v e r l a p o f s t a n d a r d e r r o r b a r s . FFD = f o r e s t f l o o r d r y , FFM = f o r e s t f l o o r m o i s t , MSD = m i n e r a l s o i l d r y , MSM = m i n e r a l s o i l m o i s t . 112 X D E o o -z. o UJ 1.0 -, Anaphalis margaritacea 0.2 H 0 10 20 30 40 50 60 70 80 90 Rubus ursinus o.o 4^**=^  0 10 20 30 40 50 60 70 m 90 * FFD o MSD 0 FFM • MSM PERCENT SHADE 113 3.4 D i s c u s s i o n In t h i s s t u d y , an average o f 58% o f t h e seed bank t a x a were found i n t h e v e g e t a t i o n o f t h e same p l o t s , and 45% o f t h e p l a n t s p e c i e s were r e p r e s e n t e d i n t h e seed bank. A poor correspondence between t h e s p e c i e s c o m p o s i t i o n o f t h e seed bank and t h e a s s o c i a t e d v e g e t a t i o n has been r e p o r t e d i n o t h e r f o r e s t seed bank s t u d i e s ( O o s t i n g and Humphreys 1940/ Olmstead and C u r t i s 1947; L i v i n g s t o n and A l l e s s i o 1968; K e l l m a n 1970, 1974; Johnson 1975; Marquis 1975; S t r i c k l e r and E d g e r t o n 1976; Whipple 1978; Kramer and Johnson 1987; see however M o r i n and P a y e t t e 1988). The t o t a l number o f s p e c i e s r e p o r t e d here (78) exceeds t h a t r e p o r t e d i n t h e o t h e r s t u d i e s c i t e d i n T a b l e 3.10. T h i s o b s e r v a t i o n may r e f l e c t one or s e v e r a l f a c t o r s , i n c l u d i n g t h e v e g e t a t i o n t y p e ( s ) , t h e age o f t h e v e g e t a t i o n , and t h e c u m u l a t i v e s u r f a c e a r e a sampled. In t h i s s t u d y , d i f f e r e n t v e g e t a t i o n u n i t s were i n t e n t i o n a l l y sampled, whereas most of t h e o t h e r s t u d i e s examined t h e seed bank of p l o t s r e p r e s e n t i n g t h e same v e g e t a t i o n t y p e . D i f f e r e n c e s i n l a t i t u d e (Johnson 1975) and e l e v a t i o n (Whipple 1978) may a l s o c o n t r i b u t e t o d i f f e r e n c e s i n s p e c i e s number and seed d e n s i t y , and make comparisons d i f f i c u l t . A p a t t e r n o f fewer g e r m i n a n t s i n d r y v e g e t a t i o n u n i t s was p r e s e r v e d a c r o s s d i s t u r b a n c e regimes. Whipple (1978) o b s e r v e d fewer v i a b l e seeds i n dry t h a n m o i s t o l d growth f o r e s t s . Dry ecosystems may have fewer g e r m i n a b l e seeds f o r s e v e r a l r e a s o n s . A comparable number of seeds may a r r i v e a t a l l s i t e s i n t h e seed r a i n , but m o r t a l i t y a f t e r a r r i v a l may be h i g h e r on d r y s i t e s due T a b l e 3.10 A comparison o f f o r e s t seed bank s t u d i e s from t h e l i t e r a t u r e . Location and Stand Total surface Number of Germinable Source vegetation type age area sampled species seeds per (years) (square meters) found square meter Kellman 1970 B r i t i s h Columbia mature Douglas-fir 100 .267 19 1016 Kellman 1974 B r i t i s h Columbia e a r l y s e r a i 8 mature Douglas-fir 100 .503 .345 (28 t o t a l ) 16 16 2612 206 Johnson 1975 Northwest T e r r i t o r i e s Spruce-lichen woodland 42-180 .478 S t r i c k l e r and Edgerton 1976 Oregon Grand f i r 130-175 .246 38 412-3447 Whipple 1978 Colorado Englemann spruce Lodgepole pine 325 325 .600 .600 53 3 Arc h i b o l d 1979 Saskatchewan Spruce-birch burned and unburned 30-50 .630 21 55-426 Pra t t et_ a l . 1984 Washington Ponderosa pine 90 .960 57 13025-14463 Kramer and Idaho Johnson 1987 Douglas-fir/Physocarpus 88 Grand fir/maple 102 Grand fir/Vaccinium 113 .760 .760 .760 46 53 47 1273 1154 753 This study B r i t i s h Columbia e a r l y s e r a i Douglas-fir 3 28-42 1.160 .720 (78 t o t a l ) 21-45 34-41 (15 species only) 520-3338 2552-4810 115 t o f a s t e r d e s i c c a t i o n and/or m e t a b o l i s m because o f hot, d r y c o n d i t i o n s . Fewer seeds may a r r i v e a t d r y s i t e s due t o t h e i r t o p o g r a p h i c p o s i t i o n ( g e n e r a l l y on upper s l o p e s o r c r e s t s ) . T h i s c o u l d have t h r e e c a u s e s : 1) s t r o n g u p d r a f t s would be r e q u i r e d t o c a r r y seeds o f m o i s t - s i t e s p e c i e s (e.g., r e d a l d e r ) ; 2) d r y s i t e s may not be used (as much) by a n i m a l s d i s p e r s i n g seeds o f some s p e c i e s (e.g., b i r d s ; Rubus); 3) seed p r o d u c t i o n on d r y s i t e s may be r e l a t i v e l y low. I c h i k a w a e t a l . (1988) a l s o found a l a r g e r b u r i e d seed p o p u l a t i o n , and deeper seed o c c u r r e n c e , on lo w e r s l o p e s t h a n on upper s l o p e s : a g r e a t e r p r o p o r t i o n o f t h e seeds was g e r m i n a b l e on upper s l o p e s , however. F o r e s t seed banks c o n t a i n e d more g e r m i n a b l e d e c i d u o u s t r e e seeds and f e r n s p o r e s t h a n d i d t h e low and h i g h d i s t u r b a n c e seed banks. D i f f e r e n c e s i n t h e seed cou n t s o f low and h i g h d i s t u r b a n c e t r a n s m i s s i o n l i n e r i g h t - o f - w a y p l o t s (Table 3.5) c o u l d be t h e r e s u l t o f s e v e r a l f a c t o r s . The l o s s o f a p o r t i o n o f th e seed bank d u r i n g s c a r i f i c a t i o n c o u l d have been p a r t i a l l y compensated f o r by subsequent seed r a i n . I t may be t h a t more seeds o f wind d i s p e r s e d s p e c i e s were t r a p p e d i n t h e rough and porous f o r e s t f l o o r o f t h e low d i s t u r b a n c e p l o t s t h a n on exposed m i n e r a l s o i l . Low seed counts o f c o n i f e r s p e c i e s a re t y p i c a l among s t u d i e s o f b u r i e d v i a b l e seed p o p u l a t i o n s i n c o n i f e r o u s f o r e s t s (Frank and S a f f o r d 1970; S t r i c k l e r and E d g e r t o n 1976). T h i s may be due t o p r e d a t i o n ( G a s h w i l e r 1967) or o t h e r f a c t o r s . I t has been found t h a t c o n i f e r seeds g e n e r a l l y r e t a i n t h e i r v i a b i l i t y under 116 normal f i e l d c o n d i t i o n s f o r l e s s t h a n 3 y e a r s ( F r a s e r 1976; Thomas and Wein 1985). The low abundance and c o n s t a n c y o f seeds o f Rubus spp. and G a u l t h e r i a s h a l l o n i n t h e h i g h d i s t u r b a n c e p l o t s may r e f l e c t t h e removal o f seeds d u r i n g s c a r i f i c a t i o n . A l t e r n a t i v e l y , t h e seeds c o u l d have been l o s t from t h e seed bank by g e r m i n a t i o n ( w i t h v a r i a b l e e s t a b l i s h m e n t s u c c e s s ) : Rubus s p e c i e s were d i a g n o s t i c o f t h e Phleum and P t e r i d i u m v e g e t a t i o n u n i t s . In t h i s s t u d y , 72% o f t h e g e r m i n a b l e seeds and s p o r e s o f t h e 15 key s p e c i e s d e t e c t e d i n f o r e s t s o i l s were l o c a t e d i n t h e f o r e s t f l o o r , 21% were i n t h e 0-5 cm l a y e r , and 7% were found i n t h e 5-10 cm l a y e r . The f o r e s t f l o o r c o n t a i n e d l a r g e numbers o f v i a b l e seeds o f A l n u s r u b r a , B e t u l a p a p y r i f e r a , A n a p h a l i s  m a r q a r i t a c e a , E p i l o b i u m w a t s o n i i , M y c e l i s m u r a l i s , and S e n e c i o  s y l v a t i c u s , and spores o f A t h y r i u m f i l i x - f e m i n a and P t e r i d i u m  a q u i l i n u m . Moore and Wein (1977) a l s o found t h e m a j o r i t y (90%) of a l l v i a b l e seeds i n t h e f o r e s t f l o o r . The seeds o f A l n u s r u b r a r e t a i n t h e i r v i a b i l i t y f o r a s h o r t p e r i o d of t i m e (Schopmeyer 1974). The p a u c i t y of s o i l a n i m a l s i n c o n i f e r o u s f o r e s t s p r e c l u d e s s i g n i f i c a n t s o i l m i x i n g (Kimmins 1987). These two p o i n t s , and t h e low d e n s i t y and c o n s t a n c y o f t h i s s p e c i e s a t depth, suggest t h a t c o n t a m i n a t i o n o f l o w e r s o i l l a y e r s d u r i n g s a m p l i n g was p r o b a b l y t h e s o u r c e o f seeds o f A. r u b r a (and B. p a p y r i f e r a ) at depth i n t h e s o i l p r o f i l e . S p e c i e s known t o have l o n g - l i v e d seeds, e.g., Rubus p a r v i f l o r u s (Schopmeyer 1974), showed a g r a d u a l d e c l i n e i n v i a b l e seed 117 numbers and c o n s t a n c y w i t h depth which i s p r o b a b l y not a s a m p l i n g a r t i f a c t . Other s t u d i e s have a l s o shown a d e c r e a s i n g number o f g e r m i n a b l e seeds w i t h i n c r e a s i n g s o i l d e p th (Kellman 1970; S t r i c k l e r and E d g e r t o n 1976; Moore and Wein 1977; Granstrom 1982; P r a t t e t a l . 1984; Kramer and Johnson 1987; I c h i k a w a e t a l . 1988) . W i n d - d i s p e r s e d seeds p o s s e s s i n g wings, a coma or pappus, were n o t a b l y more abundant and common c l o s e t o t h e i r s o u r c e s ( f o r e s t ; A. r u b r a , B. p a p y r i f e r a , r i g h t - o f - w a y ; E p i l o b i u m  w a t s o n i i , S e n e c i o s y l v a t i c u s ) , and were m o d e r a t e l y t o w i d e l y d i s t r i b u t e d t h r o u g h o u t t h e s t u d y a r e a s . Seeds w i t h o u t o b v i o u s mechanisms f o r l o n g - d i s t a n c e d i s p e r s a l (Carex spp., Galium  t r i f l o r u m ) were abundant i n t h e v i c i n i t y o f t h e i r p a r e n t p l a n t s , but were not w i d e l y d i s t r i b u t e d . In t h e f o r e s t A t h v r i u m v e g e t a t i o n u n i t , Rubus p a r v i f l o r u s seeds were found a t h i g h e r d e n s i t i e s t h a n i n t h e s l i g h t l y d r i e r M y c e l i s v e g e t a t i o n u n i t . I t i s d i f f i c u l t t o p r o v e , but t e m p t i n g t o s uggest, t h a t t h e d i f f e r e n c e s i n seed s t o r a g e a t depth i n t h e s e d i f f e r e n t v e g e t a t i o n u n i t s i s a f u n c t i o n of s o i l a n i m a l a c t i v i t y , which tends t o be g r e a t e r on m o i s t s i t e s t h a n on d r y s i t e s . Of t h e 78 o b s e r v e d s p e c i e s of g e r m i n a n t s , p r o p a g u l e s o f o n l y 4 ( G a u l t h e r i a s h a l l o n , S e n e c i o s y l v a t i c u s , A t h y r i u m f i l i x - f e m i n a , and P o l y t r i c h u m i u n i p e r i n u m ) were w i d e s p r e a d . W h i l e G. s h a l l o n seeds a r e a p p a r e n t l y w i d e l y d i s t r i b u t e d , t h i s s p e c i e s a l s o can 118 s p r e a d v e g e t a t i v e l y , and r e g e n e r a t i o n by seed i s o b s e r v e d o n l y r a r e l y ( S a b h a s r i 1961; p e r s o n a l o b s e r v a t i o n ) . O b s e r v a t i o n s on t h e l o n g e v i t y o f seeds of o t h e r s p e c i e s o f S e n e c i o (22-100 y e a r s , H a r r i n g t o n 1972), c o n s i d e r e d w i t h t h e d a t a p r e s e n t e d here suggest t h a t S. s y l v a t i c u s may p o s s e s s a p e r s i s t e n t seed bank (Grime 1979; Thompson and Grime 1979) which a l l o w s f o r t h e r e i n v a s i o n o f s i t e s a f t e r d i s t u r b a n c e . The abundance o f S_. s y l v a t i c u s seeds i n t h e s o i l o f d i s t u r b e d p l o t s r e f l e c t s t h e h i g h r e p r o d u c t i v e c a p a c i t y o f t h o s e p l a n t s which do become e s t a b l i s h e d (West and C h i l c o t e 1968). The s i g n i f i c a n t but lower seed d e n s i t i e s i n t h e f o r e s t s o i l s suggest a g r a d u a l d e c l i n e i n v i a b i l i t y o f t h e seeds. A l t e r n a t i v e l y , S. s y l v a t i c u s seeds may r e t a i n t h e i r v i a b i l i t y f o r a s h o r t p e r i o d o f t i m e , and t h e low seed d e n s i t y i n t h e f o r e s t may r e f l e c t poor d i s p e r s a l from t h e r i g h t - o f - w a y , or e l s e w h e r e , i n t o t h e f o r e s t . Spore p r o d u c t i o n by A t h y r i u m f i l i x - f e m i n a i s a p p a r e n t l y p r o l i f i c , but s u i t a b l e c o n d i t i o n s f o r t h e e s t a b l i s h m e n t o f t h i s s p e c i e s are not w i d e l y found, as can be i n f e r r e d by t h e f a i l u r e o f t h e s p o r e s t o g e r m i n a t e under th e f i e l d regime and t h e o c c u r r e n c e o f mature p l a n t s o n l y i n m o i s t , shaded s i t e s i n f o r e s t s o r c l e a r i n g s . C o n s i d e r i n g o n l y t h e 15 major seed bank s p e c i e s , 2552-4810 seeds per square meter were e s t i m a t e d t o be p r e s e n t i n t h e f o r e s t e d v e g e t a t i o n u n i t s ( f o r e s t f l o o r t o 10 cm), 1214-3338 f o r t h e low d i s t u r b a n c e v e g e t a t i o n u n i t s ( f o r e s t f l o o r t o 5 cm), and 520-1540 f o r t h e h i g h d i s t u r b a n c e v e g e t a t i o n u n i t s (0 t o 5 cm). 119 W h i l e t h e d a t a are not d i r e c t l y comparable, t h e s e numbers exceed t h o s e r e p o r t e d i n most o t h e r s t u d i e s o f c o n i f e r o u s f o r e s t seed banks (e.g., K e l l m a n 1970, 1974 S t r i c k l e r and E d g e r t o n 1976; Whipple 1978; A r c h i b o l d 1979; Moore and Wein 1977; Johnson 1975). P r a t t e t a l . (1984), however, r e p o r t e d 13,052-14,463 seeds p e r square meter i n a ponderosa p i n e community. W h i l e i t i s u n l i k e l y t h a t t h e i n c l u s i o n o f a l l 78 s p e c i e s r e c o r d e d i n t h i s s t u d y would i n c r e a s e t h e t o t a l seed d e n s i t y t o t h i s l e v e l , i t s h o u l d be n o t e d t h a t t h e t o t a l r e p o r t e d here i s an u n d e r e s t i m a t e . Water c o n d u c t i o n and l i g h t p e n e t r a t i o n a re two i m p o r t a n t c h a r a c t e r i s t i c s o f g e r m i n a t i o n s u b s t r a t e s (Wesson and Wareing 1969). W h i l e t h e water h o l d i n g c a p a c i t y o f well-decomposed f o r e s t f l o o r m a t e r i a l s (the humus l a y e r ) can be g r e a t e r t h a n t h a t of m i n e r a l s o i l , water c o n d u c t i o n i s b e t t e r i n m i n e r a l s o i l s t h a n i n l i t t e r and f e r m e n t a t i o n l a y e r s because pore and p a r t i c l e s i z e s are s m a l l e r . L i g h t p e n e t r a t e s f u r t h e r i n t o newly d e p o s i t e d f o r e s t f l o o r m a t e r i a l s (the l i t t e r l a y e r ) t h a n m i n e r a l s o i l f o r the same r e a s o n s . Wooley and S t o l l e r (1978), u s i n g t h e g e r m i n a t i o n o f l i g h t - r e q u i r i n g l e t t u c e seeds as a b i o a s s a y , found t h a t l i g h t p e n e t r a t e d b o t h sand and s i l t y c l a y loam m i n e r a l s o i l s t o a depth o f o n l y 2 mm. Mayeaux (1983) , u s i n g sand, s i l t y c l a y loam, and c l a y s o i l s , found t h a t emergence o f f o u r n a t i v e subshrubs common t o s o u t h w e s t e r n r a n g e l a n d s was s i g n i f i c a n t l y d e c r e a s e d , a t a depth o f l e s s t h a n 1 mm, compared t o emergence a t the s o i l s u r f a c e . The f i e l d samples i n t h e st u d y d e s c r i b e d here were not s t i r r e d w h i l e t h e greenhouse samples were. The reduced g e r m i n a t i o n i n t h e f i e l d seed bank g e r m i n a t i o n experiment c o u l d 120 r e f l e c t t h e c o n s t a n t b u r i a l d e p th t o which t h e f i e l d samples were s u b j e c t e d : s t i r r i n g may have exposed more seeds t o s u f f i c i e n t l i g h t . The response o f S e n e c i o s y l v a t i c u s t o g e r m i n a t i o n regime c o u l d not be d e t e r m i n e d because o f c o n t a m i n a t i o n o f t h e f i e l d samples by S.. v u l g a r i s . The s e n s i t i v i t y o f A g r o s t i s spp., Carex spp., Conyza c a n a d e n s i s , and Galium t r i f l o r u m t o g e r m i n a t i o n regime c o u l d be a f u n c t i o n o f depth o f b u r i a l , i n s o l a t i o n , water a v a i l a b i l i t y , o r a c o m b i n a t i o n o f any or a l l o f t h e s e . Because E p i l o b i u m w a t s o n i i , F e s t u c a r u b r a and M y c e l i s m u r a l i s were not a f f e c t e d by g e r m i n a t i o n regime, i t may be i n f e r r e d t h a t t h e y a r e r e l a t i v e l y i n s e n s i t i v e t o depth o f b u r i a l and i n s o l a t i o n , p r o v i d i n g s u f f i c i e n t water i s a v a i l a b l e . A n a p h a l i s m a r g a r i t a c e a and G a u l t h e r i a s h a l l o n , t h e g e r m i n a t i o n o f which was s i g n i f i c a n t l y r educed under f i e l d c o n d i t i o n s , were s e n s i t i v e t o depth o f b u r i a l and water but not shade (as r e p r e s e n t e d by t h e r e l a t i v e l y narrow range imposed i n th e g r e e n h o u s e ) . Schopmeyer (1974) r e p o r t e d t h a t m o i s t , a c i d c o n d i t i o n s under p a r t i a l shade are needed f o r t h e s u c c e s s f u l p r o p a g a t i o n o f G. s h a l l o n from seed. The s e n s i t i v i t y o f r e d a l d e r t o t h e f i e l d g e r m i n a t i o n regime i s r e f l e c t e d i n t h i s s p e c i e s ' response t o depth, shade, and m o i s t u r e as d e t e r m i n e d i n t h e g e r m i n a t i o n e x p e r i m e n t s . Red a l d e r g e r m i n a t i o n was s i g n i f i c a n t l y a f f e c t e d by depth o f b u r i a l , shade l e v e l , and m o i s t u r e regime. Ruth (1968) c o v e r e d r e d a l d e r seeds w i t h a p p r o x i m a t e l y 3 mm o f m i n e r a l s o i l i n a f i e l d experiment and 121 found g e r m i n a t i o n t o be f a r l e s s t h a n e x p e c t e d (.8 germinants p e r p l o t ; 14 e x p e c t e d ) . The s h a l l o w p e n e t r a t i o n o f l i g h t i n t o m i n e r a l s o i l , i n c o n c e r t w i t h t h e o b s e r v e d l i g h t r e q u i r e m e n t o f r e d a l d e r seeds, and t h e a l t e r a t i o n o f l i g h t q u a l i t y a f t e r p a s s i n g t h r o u g h a canopy (Bormann 1983), may account f o r t h e poor r e s u l t s r e p o r t e d by Ruth (1968). Sowing depths o f 3-6 mm a r e used c o m m e r c i a l l y , however (Schopmeyer 1974) . Bormann (1983) r e p o r t e d t h a t t h e v i a b i l i t y o f r e d a l d e r seeds may be r e t a i n e d f o r a t l e a s t 10 months i n t h e f i e l d . Seeds are d i s p e r s e d i n October and g e r m i n a t i o n o c c u r s i n A p r i l - M a y : v i a b i l i t y must be r e t a i n e d a t l e a s t 18 months f o r r e d a l d e r t o be c o n s i d e r e d t o have a p e r s i s t e n t seed bank " s t r a t e g y " . A t r a n s i e n t seed bank " s t r a t e g y " (Grime 1979; Thompson and Grime 1979), i n which d i s p e r s a l p r ecedes g e r m i n a t i o n by o n l y a s h o r t t i m e , i s more l i k e l y . Paper b i r c h ( B e t u l a p a p y r i f e r a ) seeds r e q u i r e l i g h t t o promote g e r m i n a t i o n , e s p e c i a l l y i f u n s t r a t i f i e d , and s e e d l i n g s b e n e f i t from some shade d u r i n g t h e f i r s t g rowing season (Schopmeyer 1974). These f a c t s , p a r t i c u l a r l y t h e l a t t e r , may e x p l a i n t h e low emergence of paper b i r c h from t h e f i e l d samples. I t might be p r e d i c t e d t h a t t h e f a c t o r s examined i n t h e greenhouse g e r m i n a t i o n e x p e r i m e n t s , i . e . , t h e depth o f b u r i a l , shade l e v e l , and m o i s t u r e regime, may a f f e c t paper b i r c h g e r m i n a t i o n as t h e y d i d r e d a l d e r . E p i l o b i u m a n q u s t i f o l i u m was not o b s e r v e d t o emerge from depths g r e a t e r t h a n 0.5 cm i n f o r e s t f l o o r o r 0 cm on m i n e r a l 1 2 2 s o i l . The obse'rved p a t t e r n s o f g e r m i n a t i o n under t h e d i f f e r e n t shade regimes (more g e r m i n a t i o n under 5 0 % and 80% shade t h a n under 0% shade) are i n t e r e s t i n g , but not e a s i l y e x p l a i n e d , a l t h o u g h e v a p o r a t i o n o f m o i s t u r e from th e s o i l was p r o b a b l y h i g h e r under f u l l exposure t o sun t h a n under shade. Granstrom ( 1 9 8 7 ) found t h a t seeds o f E. a n q u s t i f o l i u m d i d not d i s p l a y any i n n a t e dormancy, and g e r m i n a t e d more o r l e s s c o m p l e t e l y i n s i t u d u r i n g t h e f i r s t g rowing season o f a f i v e y e a r s t u d y . T h i s o b s e r v a t i o n , and r e p o r t s t h a t seeds remain v i a b l e f o r 1 8 months when s t o r e d d r y a t room t e m p e r a t u r e (Myerscough 1 9 8 0 ) , i m p l y t h a t seeds o f E p i l o b i u m a n q u s t i f o l i u m a r e not s t o r e d i n t h e s o i l , and t h a t p l a n t s o f t h i s s p e c i e s a r i s e from newly d e p o s i t e d seeds: E. a n q u s t i f o l i u m has a seed r a i n " s t r a t e g y " . The g e r m i n a t i o n and emergence o f Rubus s p e c i e s from depth s u g g e s t s t h a t t h e seeds o f t h e s e s p e c i e s are not l i g h t - r e q u i r i n g . In a f i e l d s t u d y o f Rubus s p e c t a b i l i s g e r m i n a t i o n , Ruth ( 1 9 7 0 ) found d e c r e a s i n g numbers o f f i r s t - y e a r s e e d l i n g s , but g r e a t e r o v e r w i n t e r s u r v i v a l , w i t h i n c r e a s i n g i n s o l a t i o n . The r e l a t i v e i n s e n s i t i v i t y o f R. p a r v i f l o r u s t o depth o f b u r i a l and l e v e l o f shade may e x p l a i n , i n p a r t , t h e l a c k o f i n f l u e n c e o f regime ( f i e l d v e r s u s greenhouse) on g e r m i n a t i o n o f t h i s s p e c i e s . R e p o r t e d seed l o n g e v i t i e s f o r Rubus s p e c i e s under f i e l d c o n d i t i o n s range between 5 0 - 1 0 0 y e a r s ( H a r r i n g t o n 1 9 7 2 ) . Granstrom ( 1 9 8 7 ) found t h a t Rubus i d a e u s r e t a i n e d 8 - 1 0 0 % v i a b i l i t y t h r o u g h o u t a 5 - y e a r f i e l d e x p e r i m e n t . The f l u s h o f Rubus s e e d l i n g s t h a t i s o f t e n o b s e r v e d a f t e r c l e a r c u t t i n g i n t h e U.S. P a c i f i c Northwest and c o a s t a l B r i t i s h Columbia a l s o 123 t e s t i f i e s t o t h e f a c t t h a t Rubus seeds are s t o r e d i n t h e s o i l ( B a i l e y and P o u l t o n 1968; Dyrness 1973; Schdpmeyer 1974; S t i c k n e y 1986; H a l p e r n 1987; Morgan and Neuenschwander 1988) . 3.5 C o n c l u s i o n s The seed bank d a t a p r e s e n t e d and d i s c u s s e d here s u g g e s t e d t h a t c a u t i o n be a p p l i e d i n e x t r a p o l a t i n g greenhouse seed bank s t u d i e s t o p o t e n t i a l s e e d l i n g p o p u l a t i o n s i n t h e f i e l d . The amount o f shade, and t h e a v a i l a b i l i t y o f water (as d e t e r m i n e d by topography, s o i l c o n d i t i o n s , and weather) w i l l e f f e c t s e e d l i n g e s t a b l i s h m e n t . The b o t h s p e c i e s c o m p o s i t i o n and seed d e n s i t y v a r i e d w i t h depth. E s t a b l i s h m e n t o f s p e c i e s from t h e seed bank w i l l be a f u n c t i o n o f t h e depth t o which t h e s o i l i s d i s t u r b e d , and t h e t r e a t m e n t o f t h e s o i l l a y e r s which have been a f f e c t e d by t h e d i s t u r b a n c e . B u r n i n g , removal, or r e d i s t r i b u t i o n o f t h e f o r e s t f l o o r w i l l r e s u l t i n d i f f e r e n t i mpacts on t h e seed bank, and d i f f e r e n t p o t e n t i a l s e e d l i n g p o p u l a t i o n s . Because r e d a l d e r i s not a p e r s i s t e n t seed bank s p e c i e s but a wind d i s p e r s e d seed r a i n s p e c i e s , l i m i t i n g t h e e s t a b l i s h m e n t o f r e d a l d e r a f t e r f o r e s t c l e a r i n g i s d i f f i c u l t , e s p e c i a l l y where mature t r e e s o f t h i s s p e c i e s are p r e s e n t i n t h e a d j a c e n t uncut f o r e s t and when s c a r i f i c a t i o n has exposed m i n e r a l s o i l . R e g e n e r a t i o n o f s h r u b s , e s p e c i a l l y Rubus spp., from t h e seed bank, i s abundant p r o b a b l y because o f t h e change i n l i g h t regime caused by canopy removal. 124 M e s i c t o m o i s t f o r e s t s i t e s have a l a r g e r seed bank t h a n do x e r i c s i t e s . R e g e n e r a t i o n o f seed bank s p e c i e s can be e x p e c t e d t o be g r e a t e r on mesic t o m o i s t s i t e s , because of b o t h t h e l a r g e r seed banks, and t h e b e t t e r m o i s t u r e regime, on t h e s e s i t e s compared t o x e r i c o r d r y s i t e s . 125 Chapter 4 S p e c i e s C o m p o s i t i o n , V i a b i l i t y , and S e a s o n a l and S p a t i a l P a t t e r n s o f D i s p e r s e d Seed 4.1 I n t r o d u c t i o n The development of a f l o r a on remote i s l a n d s such as S u r t s e y o r K r a k a t a u ( R i d l e y 1930; van der P i j l 1972) and t h e s e r i e s of communities found a l o n g t h e p a t h s of r e t r e a t i n g g l a c i e r s (Cooper 1923) a r e among t h e more o b v i o u s examples o f the i m p o r t a n c e o f seed d i s p e r s a l t o p r i m a r y s u c c e s s i o n . The p r o c e s s o f secondary s u c c e s s i o n i s more complex, and t h e f l o r a i s d e t e r m i n e d by t h e c o m p o s i t i o n and abundance o f v e g e t a t i o n and dormant buds s u r v i v i n g t h e d i s t u r b a n c e , as w e l l as t h e c o m p o s i t i o n , d i s t r i b u t i o n , and abundance o f b o t h b u r i e d v i a b l e seeds and d i s p e r s e d seeds. D e s p i t e t h e r e l e v a n c e o f seed d i s p e r s a l , o r t h e seed r a i n , t o s u c c e s s i o n a l development, most of t h e a v a i l a b l e i n f o r m a t i o n about seed d i s p e r s a l i s a n e c d o t a l and m e c h a n i s t i c ( R i d l e y 1930; van der P i j l 1972), and i s u s u a l l y c o n f i n e d t o a s i n g l e s p e c i e s and not t h e community as a whole (r e v i e w e d i n Harper 1977) . I t i s g e n e r a l l y r e c o g n i z e d t h a t d i f f e r e n c e s i n t h e l o c a l abundance o f p l a n t s p e c i e s may r e s u l t from t h e h e t e r o g e n e i t y o f seed d i s p e r s a l and s t o r a g e , d i f f e r e n t i a l s e e d l i n g e s t a b l i s h m e n t and p l a n t s u r v i v a l , v a r i a b i l i t y i n r e p r o d u c t i o n , c o m p e t i t i o n , p r e d a t i o n , o r a c o m b i n a t i o n o f some or a l l o f t h e s e f a c t o r s . Each o f t h e s e f a c t o r s has b o t h t e m p o r a l and s p a t i a l components: the s e a s o n a l and s p a t i a l p a t t e r n s o f seed d i s p e r s a l and t h e a v a i l a b i l i t y i n t i m e and space o f s u i t a b l e h a b i t a t . The 126 e x a m i n a t i o n o f a l l o f t h e s e f a c t o r s i s a s i g n i f i c a n t u n d e r t a k i n g . Few s t u d i e s have examined a l l o f t h e s e f a c t o r s f o r a s i n g l e s p e c i e s (see however Reader and Buck 1986), l e t a l o n e an e n t i r e p l a n t community. Most s t u d i e s o f seed d i s p e r s a l i n f o r e s t e d environments have been concerned w i t h t h e seed f a l l o f commercial t i m b e r s p e c i e s i n t h e c o n t e x t o f t h e p o t e n t i a l f o r t h e s u c c e s s f u l n a t u r a l r e g e n e r a t i o n o f t h o s e s p e c i e s . These s t u d i e s d e s c r i b e t h e s p a t i a l and s e a s o n a l d i s t r i b u t i o n o f v i a b l e seeds w i t h r e s p e c t t o t h e s p e c i e s c o m p o s i t i o n o f t h e seed so u r c e ( H e t h e r i n g t o n 1965; G a s h w i l e r 1967), c u t b l o c k s i z e and/or shape ( H e t h e r i n g t o n 1965; C a r k i n e t a l . 1978; Noble and Ronco 1978; McDonald 1980), or a p a r t i c u l a r s i l v i c u l t u r a l system ( W i l l i a m s o n 1983) . The p r e s e n t s t u d y compared t h e s p e c i e s c o m p o s i t i o n , g e r m i n a b i l i t y , and t h e s e a s o n a l and s p a t i a l p a t t e r n s o f t h e seed r a i n r e c e i v e d by two d i s t u r b e d s i t e s i n f o r e s t e d environments i n c o a s t a l B r i t i s h Columbia. T h i s was done i n o r d e r t o e s t i m a t e t h e i m p o r t a n c e o f t h e seed r a i n i n d e t e r m i n i n g s u c c e s s i o n a l p l a n t community c o m p o s i t i o n . The r e s e a r c h was conducted on two t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . T h i s seed r a i n s t u d y was p a r t o f a l a r g e r r e s e a r c h p r o j e c t which examined d i s t u r b a n c e and i t s impact on t h e c o m p o s i t i o n o f e a r l y s u c c e s s i o n a l p l a n t communities. The s p e c i f i c q u e s t i o n s asked were (1) what i s t h e s p e c i e s c o m p o s i t i o n and g e r m i n a b i l i t y o f t h e seed r a i n ? and (2) what are t h e s e a s o n a l and s p a t i a l p a t t e r n s of d i s p e r s a l o f d i f f e r e n t s p e c i e s ? 127 4.2 Methods 4 . 2 . 1 The s t u d y s i t e s The seed r a i n was c o l l e c t e d on t h e t r a n s m i s s i o n l i n e r i g h t -of-way and t h e a d j a c e n t f o r e s t a t two s t u d y s i t e s i n c o a s t a l B r i t i s h Columbia. The Cheekye Loop (10 km n o r t h o f Squamish) and M a l a s p i n a (30 km n o r t h w e s t o f S e c h e l t ) 500 kV t r a n s m i s s i o n l i n e r i g h t s - o f - w a y were c l e a r e d between September 1980 and December 1981 when the f o r e s t s were a p p r o x i m a t e l y 26 and 39 y e a r s o l d , r e s p e c t i v e l y . S e v e r e l y d i s t u r b e d a r e a s on b o t h r i g h t s - o f - w a y were seeded t o a mix o f agronomic g r a s s e s and legumes ( i n c l u d i n g F e s t u c a r u b r a , L o l i u m perenne, Phleum  p r a t e n s e , Poa p r a t e n s i s , T r i f o l i u m hybridum, and T. repens) a t a r a t e o f a p p r o x i m a t e l y 28 kg/ha i n 1982 t o c o n t r o l e r o s i o n and impede t h e e s t a b l i s h m e n t o f r e d a l d e r (Alnus r u b r a ) . The v e g e t a t i o n o f t h e two s i t e s i s d e s c r i b e d i n d e t a i l i n Chapter 2. At b o t h s t u d y s i t e s , t h e f o r e s t canopy was dominated by Pseudotsuqa m e n z i e s i i , T h u i a p l i c a t a , Tsuga h e t e r o p h y l l a , and A l n u s r u b r a , w i t h o c c a s i o n a l s t a n d s o f P i n u s c o n t o r t a and i n d i v i d u a l s o f A c e r macrophyllum. The dominant v a s c u l a r s p e c i e s on t h e r i g h t s - o f - w a y i n c l u d e d P t e r i d i u m a g u i l i n u m , A l n u s r u b r a , A n a p h a l i s m a r q a r i t a c e a , E p i l o b i u m a n g u s t i f o l i u m , G a u l t h e r i a  s h a l l o n , Rubus p a r v i f l o r u s , R. l e u c o d e r m i s , and R. u r s i n u s . 128 4.2.2 Seed c o l l e c t i o n and p r o c e s s i n g S i x t r a n s e c t s , o r i e n t e d p e r p e n d i c u l a r t o t h e r i g h t - o f - w a y , were e s t a b l i s h e d a t each s i t e . The t r a n s e c t s were p a i r e d : w i t h i n each p a i r , t h e t r a n s e c t s were 25-30 m a p a r t . The d i s t a n c e between t r a n s e c t p a i r s was 225-250 m a t M a l a s p i n a and 250-400 m a t t h e Cheekye Loop. Seven t r a p s were p o s i t i o n e d a l o n g each t r a n s e c t : t r a p s 1 and 7 were l o c a t e d i n t h e f o r e s t (3-10 m from t h e r i g h t - o f - w a y ) and t h e 5 r e m a i n i n g t r a p s (2-6) were p l a c e d a t r e g u l a r i n t e r v a l s a c r o s s t h e r i g h t - o f - w a y ( F i g u r e 4.1). At t h e M a l a s p i n a s i t e , where t h e r i g h t - o f - w a y i s 100 m wide, t h e t r a p s were p l a c e d a p p r o x i m a t e l y 16.5 m from t h e f o r e s t edge and 16.5 m a p a r t . At t h e Cheekye Loop r i g h t - o f - w a y (200 m w i d e ) , t r a p s were p l a c e d a p p r o x i m a t e l y 33 m from t h e f o r e s t edge and 33 m a p a r t . The seed t r a p s were 26 X 52 X 6 cm p l a s t i c t r a y s which were l i n e d w i t h p l a s t i c windowscreen mesh (2 X 1.5 mm) t o c a p t u r e seeds, and c o v e r e d w i t h 2 cm g a l v a n i z e d hexagonal mesh hardware c l o t h t o e x c l u d e seed p r e d a t i o n by r o d e n t s and b i r d s . The t r a p s were p l a c e d d i r e c t l y on t h e ground. (The term "seed" i s used, except when r e f e r r i n g t o a p a r t i c u l a r s p e c i e s f o r which t h e term i s not a c c u r a t e . The p r o p a g u l e s i n c l u d e d b o t h seeds and f r u i t s . ) The t r a p s were checked monthly from A p r i l 1984 t h r o u g h March 1986. T h i s was e q u i v a l e n t t o 996 trap-months a t each s i t e , f o r a t o t a l o f 1992 trap-months. F o r t h o s e t r a p s which c o n t a i n e d seeds, t h e l i n e r was r o l l e d up, p l a c e d i n a l a b e l l e d 129 • seed trap Figure 4.1 A schematic diagram of the arrangement of seed traps in the forests and on the rights-of-way. Two of six transects i l l u s t r a t e d . 130 p l a s t i c bag, and r e p l a c e d w i t h a new l i n e r . Any seeds which had f a l l e n t h r o u g h t h e l i n e r were c o l l e c t e d from t h e bottom o f t h e p l a s t i c t r a y and added t o t h e l a b e l l e d sample bag. Seeds were i d e n t i f i e d t o s p e c i e s where p o s s i b l e , u s i n g f i e l d c o l l e c t i o n s as r e f e r e n c e , and counted. Nomenclature f o l l o w s H i t c h c o c k and C r o n q u i s t (1973). The f r u i t s o f t h e genus A c e r , and seeds o f Cornus s e r i c e a and Rhamnus p u r s h i a n a were s u b j e c t e d t o c u t t i n g t e s t s t o determine i f embryos were p r e s e n t . F o r a l l o t h e r s p e c i e s , g e r m i n a b i l i t y was a s s e s s e d a f t e r c o l d , m o i s t s t r a t i f i c a t i o n (1-3°C f o r 1 month). G e r m i n a t i o n t e s t s o f samples from t h e f i r s t y e a r ( A p r i l 1984 - March 1985) were conducted on a Jacobsen g e r m i n a t o r ( d a y l e n g t h 12 h r , 25°C day; 20°C n i g h t ) . Seeds c o l l e c t e d d u r i n g t h e second y e a r ( A p r i l 1985 - March 1986) were p l a c e d on a s t e r i l i z e d sandy loam s o i l , and f o l l o w i n g c h i l l i n g t h e samples were moved t o a greenhouse and g e r m i n a t i o n was r e c o r d e d over a 3-month p e r i o d . Seed samples on the Jacobsen g e r m i n a t o r were s u b j e c t e d t o a v e r y d i f f e r e n t t e m p e r a t u r e and h u m i d i t y regime, and o f t e n molded d e s p i t e t r e a t m e n t w i t h z i n c s u l f a t e (ZnSC>4) . S t r i c t comparison o f t h e g e r m i n a b i l i t y between seed y e a r s cannot be made because t h e r e s u l t s a re confounded by t h e d i f f e r e n t methods of assessment. 4.2.3 Data a n a l y s i s Traps were o c c a s i o n a l l y v a n d a l i z e d by humans, were o v e r t u r n e d or damaged by o t h e r a n i m a l s , or were m i s s i n g . A t o t a l o f 56 trap-months (17 a t t h e Cheekye Loop, 39 at M a l a s p i n a ) were l o s t . I n o r d e r t o c a l c u l a t e t h e numbers of 131 p r o p a g u l e s p e r square meter based on t h e same number of t r a p s p e r month and trap-months p e r s t a t i o n , t h e m i s s i n g d a t a were r e p l a c e d . I f a t r a p was m i s s i n g , a l l i m m e d i a t e l y a d j a c e n t t r a p s were checked f o r p r o p a g u l e s of a s p e c i e s : i f none o f t h e t r a p s c o n t a i n e d seeds o f t h a t s p e c i e s , t h e v a l u e "0" was e n t e r e d f o r t h a t s p e c i e s i n t h e m i s s i n g t r a p . I f a d j a c e n t t r a p s d i d c o n t a i n seeds of t h e s p e c i e s i n q u e s t i o n , t h e n t h e mean v a l u e o f s e e d s / t r a p f o r t h a t s p e c i e s i n t h a t row ( i . e . , t r a p s a t t h e same d i s t a n c e from t h e f o r e s t ) was e n t e r e d f o r t h e m i s s i n g t r a p . The v a l u e s so c a l c u l a t e d a r e o n l y e s t i m a t e s . There were two p e r i o d s when heavy snow-cover p r e v e n t e d t h e l o c a t i n g o f t r a p s (179 trap-months at t h e Cheekye Loop, 126 a t M a l a s p i n a ) . When the t r a p s were c o v e r e d by snow on t h e s a m p l i n g d a t e , t h e number of p r o p a g u l e s d i s p e r s e d d u r i n g t h a t month was c a l c u l a t e d t o be a p o r t i o n o f t h e seed r a i n found i n t h e t r a p s t h e n e x t t i m e t h e t r a p s were c o l l e c t e d . T h i s s i t u a t i o n was h a n d l e d i n two ways. F i r s t , i f a l l t r a p s were snow-covered at one or more s a m p l i n g d a t e s , t h e seeds c o l l e c t e d a f t e r snow melt were d i s t r i b u t e d among the s a m p l i n g p e r i o d s i n p r o p o r t i o n t o t h e number of days i n each p e r i o d . T h i s assumes t h a t t h e seed r a i n was e v e n l y d i s t r i b u t e d over t h e d u r a t i o n of t h e p e r i o d w i t h snow. I f some t r a p s were snow-covered at a s a m p l i n g d a t e , t h e seeds found i n a p r e v i o u s l y snow-covered t r a p a t t h e next snow-f r e e s a m p l i n g date were d i s t r i b u t e d between t h e s a m p l i n g p e r i o d s 132 i n t h e r a t i o o f t h e sum o f a l l seeds c o l l e c t e d i n snow-free t r a p s a t t h e two s a m p l i n g d a t e s . T h i s assumes t h a t t h e seeds of a l l s p e c i e s were d i s p e r s e d i n t h e same p a t t e r n o f abundance d u r i n g t h e d u r a t i o n of snow c o v e r . 4.3 R e s u l t s 4.3.1 S p e c i e s c o m p o s i t i o n and v i a b i l i t y A t o t a l o f 20,203 seeds were t r a p p e d i n t h e two y e a r s . T h i r t y - e i g h t n a t i v e or n a t u r a l i z e d t a x a (Cheekye 28, M a l a s p i n a 2 5 ) , 5 seeded t a x a , and s e v e r a l u n i d e n t i f i e d s p e c i e s (lumped t o g e t h e r i n one c a t e g o r y ) were found (Table 4.1). The seed r a i n was dominated by o n l y a few s p e c i e s . Only f o u r s p e c i e s , A l n u s  r u b r a , B e t u l a p a p y r i f e r a , Tsuga h e t e r o p h y l l a , and H o l o d i s c u s  d i s c o l o r , were found i n more t h a n 20 o f t h e seed t r a p s on t h e r i g h t s - o f - w a y or 6 o f t h e seed t r a p s i n t h e f o r e s t i n one o f t h e two y e a r s o f s a m p l i n g . More s p e c i e s were t r a p p e d on t h e r i g h t s - o f - w a y t h a n i n t h e f o r e s t s . As i s commonly found i n seed r a i n s t u d i e s (Kellman 1974/ A r c h i b o l d 1980/ E v e r e t t and Sharrow 1983), t h e s p a t i a l d i s t r i b u t i o n o f d i s p e r s i n g seeds was h i g h l y v a r i a b l e : t h i s can be i n f e r r e d from t h e t r a p p i n g f r e q u e n c i e s shown i n Table 4.1. Seeds of Rubus spp. and G a u l t h e r i a s h a l l o n are d i s p e r s e d b i r d s and i n t a c t f r u i t s f a l l o f f p l a n t s : t h e i r o c c u r r e n c e i n seed t r a p s i s p r o b a b l y more a r e f l e c t i o n o f t r a p l o c a t i o n , a n i m a l b e h a v i o r , and chance, t h a n t h e abundance of f r u i t s . 133 T a b l e 4.1 T o t a l number o f seeds a c t u a l l y t r a p p e d , and f r e q u e n c y ( i n p a r e n t h e s e s ) o v e r t h e two-year s a m p l i n g p e r i o d a t t h e Cheekye Loop and M a l a s p i n a s t u d y s i t e s . - = s p e c i e s not o b s e r v e d on t h e s i t e . Maximum p o s s i b l e f r e q u e n c y i s 60 on t h e r i g h t s - o f - w a y and 24 i n t h e f o r e s t s . Cheekye Loop Malaspina Right-of-way Forest Right-of-way Forest WINGED FRUITS/SEEDS ~ ~ _ ~ CONIFEROUS TREES Abies qrandis - - 1 (1) 1 (1) Pinus contorta 12 (4) -Pseudotsuqa me n z i e s i i 16 (13) 27 (10) 9 (8) 7 (7) Thuia p l i c a t a 44 (11) 14 (7) 34 (19) 68 (12) Tsuqa h e t e r o p h y l l a 79 (31) 247 (19) 131 (36) 243 (15) DECIDUOUS TREES/SHRUBS Acer c i r c i n a t u m 9 (5) 21 (4) - -Acer macrophyllum 2 (2) 9 (2) Alnus rubra 149 (41) 2876 (17) 418 (58) 1783 (24) Alnus sinuata 65 (5) 1 (1) - _ Betula p a p y r i f e r a 159 (36) 2581 (18) -FLESHY FRUITS Amelanchier a l n i f o l i a 8 (2) _ _ Cornus s e r i c e a 1 (1) 3 (2) _ _ G a u l t h e r i a s h a l l o n 418 (8) 303 (4) 7 (2) 12 (1) Prunus emarqinata 1 (1) 3 (2) 2 (2) 4 (2) Rhamnus purshiana 1 (1) 10 (1) Rubus spp. 1381 (17) 311 (7) 1289 (17) 5 (3) Vaccinium p a r v i f o l i u m 173 (2) 57 (1) DRY SEEDS/FRUITS A q r o s t i s s t o l o n i f e r a 104 (6) 18 (5) A i r a praecox - - 128 (5) Carex spp. 3 (2) 2 (1) 2 (1) Collomia h e t e r o p h y l l a - - 3 (3) Danthonia s p i c a t a 47 (4) _ _ Galium t r i f l o r u m 7 (4) 57 (5) Holodiscus d i s c o l o r 395 (37) 253 (10) 1141 (36) 142 (11) L i l i u m columbianum 11 (1) _ — Luzula p a r v i f l o r a 24 (1) S p e r q u l a r i a sp. 30 (1) -Spiraea d o u q l a s i i * 14 (1) Trisetum cernuum 13 (3) PLUMED FRUITS Anaphalis marqaritacea 491 (15) 9 (4) 95 (13) Cirsium vulqare 5 (3) Epilobium spp. 16 (5) 4 (4) 12 (9) 5 (4) Hieracium a l b i f l o r u m 5 (4) 70 (10) Hypochoeris r a d i c a t a 5 (3) 12 (2) Mycelis muralis 39 (12) 1 (1) 37 (6) U n i d e n t i f i e d species 37 31 24 2 SEEDED GRASSES/LEGUMES Festuca rubra 92 (21) 1 (1) 1567 (54) 1 (1) Lolium perenne 18 (8) 1 (1) 307 (33) Phleum pratense 180 (10) 1579 (41) 4 (2) Poa p r a t e n s i s 41 (9) 67 (10) T r i f o l i u m spp. 1 (1) 60 (9) TOTAL SPECIES 37 28 33 15 TOTAL SEEDS 4025 6775 7117 2286 * = f o l l i c l e count o n l y 134 The seeded agronomic g r a s s e s and legumes were major components o f t h e seed r a i n , p a r t i c u l a r l y a t M a l a s p i n a . As a group, t h e agronomic s p e c i e s c o n t r i b u t e d 37 seeds/m 2 t o t h e t o t a l seed r a i n on t h e Cheekye Loop r i g h t - o f - w a y i n 1984-85 and 46 i n 1985-86. At M a l a s p i n a , t h e y c o n t r i b u t e d 442 and 475 seeds/m 2 i n t h e two y e a r s , r e s p e c t i v e l y , r e f l e c t i n g t h e g r e a t e r a r e a seeded (and t r a p l o c a t i o n ) a t t h a t s i t e compared t o t h e Cheekye Loop. The c o n t r i b u t i o n o f t h e n a t i v e and n a t u r a l i z e d s p e c i e s t o th e e s t i m a t e s o f t h e annual seed r a i n v a r i e d w i d e l y from y e a r t o ye a r (Table 4.2). E l e v e n t a x a a c c o u n t e d f o r 97% o f t h e t o t a l seed r a i n a t t h e Cheekye Loop i n t h e f i r s t y e a r , and 13 t a x a a c c o u n t e d f o r 97% i n t h e second y e a r . At M a l a s p i n a , 11 t a x a a c c o u n t e d f o r 93% o f t h e t o t a l seed r a i n i n t h e f i r s t y e a r and 99% i n t h e second y e a r . F o r s p e c i e s whose p r o p a g u l e s were w i d e l y d i s p e r s e d ( i . e . , o c c u r r i n g i n a t l e a s t 30% o f t h e r i g h t -of-way o r f o r e s t t r a p s i n one o f t h e two y e a r s a t one o f t h e two st u d y s i t e s ) , t h e mean number o f seeds/m 2 t r a p p e d i s g i v e n i n Table 4.3. F o r a l l of t h e s e s p e c i e s , t h e number o f seeds t r a p p e d was g r e a t e r i n t h e second y e a r t h a n i n t h e f i r s t . The mean number o f g e r m i n a b l e seeds/m 2 t r a p p e d f o r t h e s e s p e c i e s i s g i v e n i n Ta b l e 4.4, and Ta b l e 4.5 c o n t a i n s e s t i m a t e s o f p e r c e n t g e r m i n a b i l i t y by y e a r and s t u d y s i t e . The g e r m i n a b i l i t y o f most s p e c i e s was g r e a t e r i n t h e second y e a r , but t h e r e s u l t s a r e confounded by t h e change i n methodology. The few seeds a v a i l a b l e f o r e s t i m a t i n g t h e g e r m i n a b i l i t y o f E p i l o b i u m spp. make any c o n c l u s i o n s about t h i s s p e c i e s tenuous. 135 Table 4.2 The most i m p o r t a n t n a t i v e (or n a t u r a l i z e d ) t a x a , based on t h e number of seeds t r a p p e d , from t h e s t u d y s i t e s by c o n t r i b u t i o n t o t h e seed r a i n on t h e r i g h t - o f - w a y . a) Cheekye Loop; b) M a l a s p i n a . Data are c o r r e c t e d f o r m i s s i n g t r a p s . a) Cheekye Loop 1984 -1985 1985 -1986 Seeds/ % o f Seeds/ % o f m e t e r 2 T o t a l m e t e r 2 T o t a l G a u l t h e r i a s h a l l o n 70 39 33 5 H o l o d i s c u s d i s c o l o r 37 21 62 9 Rubus spp. 17 9 325 45 A a r o s t i s s t o l o n i f e r a 11 6 15 2 Danthonia s p i c a t a 11 6 1 + A n a p h a l i s m a r g a r i t a c e a 9 5 112 15 M v c e l i s m u r a l i s 9 5 1 + A l n u s r u b r a 8 4 29 4 B e t u l a p a p y r i f e r a 4 2 36 5 Tsuga h e t e r o p h y l l a 3 2 17 2 T h u i a p l i c a t a + 0 11 2 A l n u s s i n u a t a 0 0 16 2 V a c c i n i u m p a r v i f o l i u m 0 0 43 6 A l l o t h e r t a x a (13) 5 3 23 3 b) M a l a s p i n a 1984 -1985 1985- 1986 Seeds/ % o f Seeds/ % o f m e t e r 2 T o t a l m e t e r 2 T o t a l H o l o d i s c u s d i s c o l o r 66 30 217 32 A l n u s r u b r a 46 21 69 10 A i r a p r a e c o x 27 12 6 1 Rubus spp. 23 11 295 44 A n a p h a l i s m a r g a r i t a c e a 11 5 15 2 Galium t r i f l o r u m 10 5 4 1 H i e r a c i u m a l b i f l o r u m 8 4 9 1 A g r o s t i s s t o l o n i f e r a 4 2 1 + M y c e l i s m u r a l i s 3 1 6 1 Tsuga h e t e r o p h y l l a 2 1 34 5 Th u i a p l i c a t a 2 1 8 1 A l l o t h e r t a x a (12) 16 7 9 1 + = l e s s t h a n 0.5 seeds/m 136 Table 4.3 Mean number of seeds p e r square meter + s t a n d a r d e r r o r , f o r t h o s e s p e c i e s o c c u r r i n g i n at l e a s t 30% o f t h e r i g h t -of-way o r f o r e s t t r a p s at one o f t h e two st u d y s i t e s i n one o f t h e two t r a p p i n g y e a r s , a) t h e Cheekye Loop; b) M a l a s p i n a . Data are c o r r e c t e d f o r m i s s i n g t r a p s . a) Cheekye Loop R i g h t - o f - w a y F o r e s t 84-85 85-86 84-85 85-86 A l n u s r u b r a 8 ± 2 29 ± 9 229 ± 65 1554 ± 702 A n a p h a l i s m a r q a r i t a c e a 9 ± 5 112 ± 44 0 0 B e t u l a p a p v r i f e r a 4 ± 1 36 ± 5 117 ± 56 1490 ± 661 E p i l o b i u m spp. 0 4 ± 3 0 3 ± 1 H o l o d i s c u s d i s c o l o r 37 ± 17 62 ± 35 116 ± 99 43 ± 26 Pseudotsuqa m e n z i e s i i 0 4 ± 1 2 ± 1 15 ± 4 Rubus spp. 17 ± 6 325 ± 207 34 ± 26 158 ± 145 Th u i a p l i c a t a + 11 ± 8 3 ± 1 7 ± 3 Tsuqa h e t e r o p h y l l a 3 ± 1 17 ± 3 15 ± 8 148 ± 91 b) M a l a s p i n a R i g h t - o f - w a y F o r e s t 84-85 85-86 84-85 85-86 A l n u s r u b r a 46 ± 7 69 ± 17 238 ± 77 861 + 343 A n a p h a l i s m a r q a r i t a c e a 11 ± 8 15 ± 10 0 0 E p i l o b i u m spp. 1 ± 1 2 ± 1 0 3 ± 1 H o l o d i s c u s d i s c o l o r 66 ± 33 217 ± 85 57 ± 27 30 ± 18 Pseudotsuqa m e n z i e s i i + 2 ± 1 1 ± 1 4 ± 1 Rubus spp. 23 ± 13 295 ± 182 0 3 ± 2 Th u i a p l i c a t a 2 ± 1 8 ± 2 21 ± 12 21 ± 9 Tsuqa h e t e r o p h y l l a 2 + 1 34 + 4 9 ± 7 141 ± 64 + = l e s s t h a n one seed p e r square meter 137 T a b l e 4.4 E s t i m a t e s o f t h e mean number o f g e r m i n a b l e seeds p e r square meter - s t a n d a r d e r r o r o f t h o s e s p e c i e s o c c u r r i n g i n a t l e a s t 30% o f t h e r i g h t - o f - w a y o r f o r e s t t r a p s a t one o f t h e two st u d y s i t e s i n one o f t h e two t r a p p i n g y e a r s , a) t h e Cheekye Loop; b) M a l a s p i n a . Data are c o r r e c t e d f o r m i s s i n g t r a p s . a) Cheekye Loop R i g h t - o f - w a y F o r e s t 84-85 85-86 84-85 85-86 A l n u s r u b r a 1 ± 0 15 ± 6 14 ± 10 787 ± 400 A n a p h a l i s m a r c r a r i t a c e a 5 ± 3 66 ± 25 0 0 B e t u l a p a p y r i f e r a 0 12 ± 2 8 ± 4 369 ± 192 E p i l o b i u m spp. 0 1 ± 0 0 1 ± 1 H o l o d i s c u s d i s c o l o r 1 ± 0 7 ± 4 15 ± 12 6 ± 4 Pseudotsucra m e n z i e s i i 0 1 ± 0 0 2 ± 1 Rubus spp. 1 ± 1 13 ± 10 12 ± 10 41 ± 38 Th u i a p l i c a t a 0 3 + 2 1 ± 1 1 + 1 Tsuga h e t e r o p h y l l a 0 6 ± 2 0 61 ± 41 b) M a l a s p i n a R i g h t - o f - w a y F o r e s t 84-85 85-86 84-85 85-86 A l n u s r u b r a 3 ± 2 A n a p h a l i s m a r g a r i t a c e a 8 ± 6 E p i l o b i u m spp. 1 ± 1 H o l o d i s c u s d i s c o l o r + Pseudotsuga m e n z i e s i i 0 Rubus spp. 1 ± 0 Th u i a p l i c a t a 0 Tsuga h e t e r o p h y l l a + 29 ± 7 2 2 + 7 324 ± 134 10 ± 7 0 0 + 0 1 ± 1 4 ± 2 4 ± 2 7 1 ± 1 8 0 0 0 64 ± 46 0 1 ± 1 3 ± 1 0 14 ± 8 8 ± 1 0 32 ± 17 + = l e s s t h a n one seed/m^. A s t a n d a r d e r r o r o f 0 r e s u l t s from r o u n d i n g 0.01-0.4 9 downward t o 0. 138 T a b l e 4 .5 E s t i m a t e s o f seed g e r m i n a b i l i t y based on t h e t o t a l number o f seeds a c t u a l l y t r a p p e d , a) th e Cheekye Loop; b) M a l a s p i n a . TOT = t o t a l ; GERM = g e r m i n a t i n g ; % = (GERM/TOT)xlOO. a) Cheekye Loop 84-85 85-86 TOT GERM % TOT GERM % A l n u s r u b r a 369 24 6 2629 1334 51 A n a p h a l i s m a r a a r i t a c e a 38 20 53 462 272 59 B e t u l a p a o y r i f e r a 205 13 6 2535 647 26 E p i l o b i u m spp. 0 20 3 15 H o l o d i s c u s d i s c o l o r 333 27 8 315 37 12 Pseudotsuqa m e n z i e s i i 4 0 0 39 6 15 Rubus spp. 115 0 0 1573 0 0 T h u i a p l i c a t a 5 0 0 53 13 25 Tsuqa h e t e r o p h y l l a 36 1. 3 290 113 39 b) M a l a s p i n a 84-85 85-86 TOT GERM % TOT GERM % A l n u s r u b r a 551 47 9 1650 663 40 A n a p h a l i s m a r q a r i t a c e a 40 30 75 55 37 67 E p i l o b i u m spp. 3 3 100 14 2 14 H o l o d i s c u s d i s c o l o r 359 8 2 924 17 18 Pseudotsuqa m e n z i e s i i 2 0 0 14 0 0 Rubus soo. 93 4 4 1201 260 22 T h u i a p l i c a t a 40 0 0 62 32 52 Tsuqa h e t e r o p h y l l a 23 1 4 351 80 23 139 4.3.2 S e a s o n a l p a t t e r n s F i g u r e 4.2 shows t h e s e a s o n a l and a n n u a l v a r i a t i o n i n p a t t e r n s o f seed f a l l on t h e r i g h t s - o f - w a y a t Cheekye and M a l a s p i n a f o r s e l e c t e d s p e c i e s (or s p e c i e s g r o u p s ) . Data are e x p r e s s e d as t h e p e r c e n t o f t h e t o t a l number of seeds t r a p p e d f o r t h o s e s p e c i e s or s p e c i e s groups over t h e two-year p e r i o d . In g e n e r a l , seeds d i s p e r s e d i n J a n u a r y , F e b r u a r y and March were of t r e e o r i g i n . Few i f any seeds were r e l e a s e d i n A p r i l , May and June. J u l y , August, September and October seeds were p r e d o m i n a n t l y t h o s e from shrubs and c o m p o s i t e s . September, October, November and December seed r a i n came from shrubs and t r e e s . W h i l e seeds of w e s t e r n hemlock (Tsuga h e t e r o p h y l l a ) were found almost a l l y e a r ( F i g . 4.2a), v i a b l e seeds o f t h i s s p e c i e s were found almost e x c l u s i v e l y from September t o F e b r u a r y o f t h e second y e a r . The peak i n w e s t e r n hemlock d i s p e r s a l i n t h e second y e a r o c c u r r e d i n October. D i s p e r s a l o f r e d a l d e r (Alnus rubra) f r u i t s was b i m o d a l , and peaked i n November and F e b r u a r y o f t h e f i r s t y e a r . T h i s b i m o d a l p a t t e r n was not r e p e a t e d i n t h e second y e a r , when t h e number o f t r a p p e d f r u i t s o f r e d a l d e r peaked i n November-December at M a l a s p i n a and J a n u a r y - F e b r u a r y a t Cheekye Loop. D i s p e r s a l o f H o l o d i s c u s d i s c o l o r was m o d e r a t e l y (Cheekye Loop) t o s t r o n g l y (Malaspina) b i m o d a l . At t h e Cheekye Loop, d i s p e r s a l was almost c o n t i n u o u s i n t h e f i r s t y e a r (August-March, 140 F i g u r e 4.2 The monthly d i s p e r s a l r a t e s o f s e l e c t e d s p e c i e s , e x p r e s s e d as t h e p e r c e n t o f t h e two-year t o t a l . 7. of Total Seeds Trapped 7. of Total Seeds Trapped 142 9 months), w h i l e a t M a l a s p i n a d i s p e r s a l o c c u r r e d over a 5-month p e r i o d (August-December). D u r i n g t h e second y e a r , t h e peak d i s p e r s a l month was August a t t h e Cheekye Loop and September a t M a l a s p i n a . D i s p e r s a l o f Rubus seed i n t h e second y e a r o c c u r r e d from J u l y t o January and seeds were p r i m a r i l y from Rubus l e u c o d e r m i s , th e f r u i t s o f which dropped i n t a c t from t h e p a r e n t p l a n t d u r i n g th e w i n t e r months. Seeds o f Rubus p a r v i f l o r u s and Rubus u r s i n u s were found i n b i r d d r o p p i n g s d u r i n g t h e summer months. There were two d i s t i n c t peaks i n t h e d i s p e r s a l o f composites ( A n a p h a l i s m a r q a r i t a c e a , H y p o c h o e r i s r a d i c a t a , H i e r a c i u m a l b i f l o r u m , C i r s i u m v u l g a r e , and M y c e l i s m u r a l i s ) a t M a l a s p i n a . The f i r s t peak, i n J u l y , was due t o H i e r a c i u m  a l b i f l o r u m i n t h e f i r s t y e a r , and b o t h H. a l b i f l o r u m and M. m u r a l i s i n t h e second y e a r . The second peak, i n October, r e p r e s e n t e d t h e d i s p e r s a l o f t h e f r u i t s o f A. m a r q a r i t a c e a . Other s t u d i e s have a l s o demonstrated a s t r o n g l y b i m o d a l t e m p o r a l p a t t e r n o f seed d i s p e r s a l o f herbaceous s p e c i e s (Wagner 1965; R a b i n o w i t z and Rapp 1980; M o r r i s e t a l . 1986) . 4.3.3 S p a t i a l p a t t e r n s F i g u r e 4.3 shows t h e s p a t i a l p a t t e r n of seed d i s p e r s a l f o r t h r e e s p e c i e s groups. The seed f a l l o f t h e t r e e s p e c i e s was g r e a t e r i n t h e f o r e s t t h a n on t h e r i g h t - o f - w a y . Seed p r o d u c t i o n by r e d a l d e r o c c u r r e d o n l y i n t h e f o r e s t s . The d i f f e r e n c e i n d i s p e r s a l p a t t e r n between t h e Cheekye Loop ( h i g h seed c o u n t s i n 143 Figure 4.3 Number of seeds/in^ trapped as a function of trapping station. The lengths of the X axes are proportional to the widths of the rights-of-way (200 m at the Cheekye Loop, 100 m at Malaspina). 1 4 4 Cheekye Loop Trees Malaspina eooo sooo -4000 3000 2000 -1000 0 ~t 1 1 : 1 T 7 6 Rubus spp. 2000 1600 -1000 600 Composites Seedtrap station 145 b o t h f o r e s t edges) and M a l a s p i n a ( h i g h seed count on o n l y one s i d e ) p r i m a r i l y r e f l e c t s t h e i m p o r t a n c e o f r e d a l d e r , which was p r e s e n t i n t h e f o r e s t on t h e n o r t h and s o u t h s i d e s o f t h e r i g h t -of-way at t h e Cheekye Loop, but o n l y t h e s o u t h a t M a l a s p i n a . C o n s i s t e n t d i f f e r e n c e s between t h e f o r e s t and r i g h t - o f - w a y , i n t h e p a t t e r n o f seed r a i n o f Rubus s p e c i e s , were not found. Seed p r o d u c t i o n o f Rubus s p e c i e s was o b s e r v e d e x c l u s i v e l y on t h e r i g h t s - o f - w a y . The seed r a i n o f herbaceous s p e c i e s (composites) was a l s o g r e a t e r on t h e r i g h t s - o f - w a y t h a n i n t h e f o r e s t s . Seed p r o d u c t i o n by t h e s e s p e c i e s was not o b s e r v e d near t h e t r a p s i n t h e f o r e s t s . 4.4 D i s c u s s i o n There are s e v e r a l f a c t o r s which may have r e s u l t e d i n e r r o r s i n t h e e s t i m a t i o n o f t h e seed r a i n . F i r s t , t h e c o r r e c t i o n s f o r m i s s i n g t r a p s (2.8% o f t h e t o t a l trap-months)-, c a l c u l a t e d as d e s c r i b e d above, were o n l y e s t i m a t e s . F o r t h e few s p e c i e s which were w i d e l y and more or l e s s e v e n l y d i s t r i b u t e d , t h e s e e s t i m a t e s are p r o b a b l y r e a s o n a b l e . The v a l u e s f o r t h o s e s p e c i e s which were found i n o n l y one or a few t r a p s may be i n a c c u r a t e , however, and t h e s e s p e c i e s may be e i t h e r o v e r - or under-r e p r e s e n t e d . Second, some s p e c i e s may be u n d e r - r e p r e s e n t e d i f t h e i r seeds were s m a l l e r t h a n t h e mesh and i f t h e y f e l l t h r o u g h b o t h t h e mesh and one of t h e few d r a i n a g e h o l e s ( a p p r o x i m a t e l y 3 X 6 mm) i n t h e bottom of t h e t r a p s . T h i r d , t h e dense canopy formed by t h e agronomic s p e c i e s over t h e r i g h t - o f - w a y t r a p s i n l a t e summer may have impeded or d e f l e c t e d d i s p e r s i n g seeds ( R a b i n o w i t z and Rapp 1980). F o u r t h , because o f t h e t h i r d f a c t o r , t h e culms o f t h e g r a s s e s were bent a s i d e i n t h e autumn t o open t h e t r a p s t o t h e seeds and f r u i t s o f n a t i v e s p e c i e s . Because d i s p e r s a l o f t h e agronomic s p e c i e s c o n t i n u e d t h r o u g h a t l e a s t November, e s t i m a t e s of t h e seed c o u n t s f o r t h e s e s p e c i e s were p r o b a b l y low. Because t h e n a t i v e s p e c i e s were of p r i m a r y i n t e r e s t , t h i s a c t i o n was c o n s i d e r e d t o be j u s t i f i e d . F i n a l l y , i t i s p o s s i b l e t h a t seeds which d i s p e r s e d i n months w i t h snow co v e r were r e d i s t r i b u t e d a c r o s s t h e s u r f a c e o f t h e snow by wind: seeds c o u l d have been moved away from, o r t o , t r a p s . The v a l u e s f o r numbers o f g e r m i n a b l e seeds s h o u l d be c o n s i d e r e d t o be u n d e r e s t i m a t e s . The u n i f o r m s t r a t i f i c a t i o n t r e a t m e n t may not have been s u f f i c i e n t t o meet t h e dormancy r e q u i r e m e n t s of a l l s p e c i e s , p a r t i c u l a r l y f o r hard-seeded s p e c i e s such as Rubus spp. which have s t r o n g endogenous dormancy mechanisms. F u r t h e r m o r e , i t s h o u l d be emphasized t h a t g e r m i n a b i l i t y i s not e q u i v a l e n t t o v i a b i l i t y : t h o s e seeds which d i d not g e r m i n a t e c o u l d have been e i t h e r dormant, dead or u n f i l l e d . The change i n apparent g e r m i n a b i l i t y between t h e two y e a r s may be due t o t h e change i n methodology. I t i s known, however, t h a t low seed g e r m i n a t i o n r a t e s are c h a r a c t e r i s t i c o f poor seed c r o p s o f r e d a l d e r (Alnus rubra) and paper b i r c h ( B e t u l a p a p y r i f e r a ) (Schopmeyer 1974). The seed c r o p o f r e d a l d e r was l a r g e r , and g e r m i n a b i l i t y was h i g h e r , i n t h e second y e a r o f t r a p p i n g a t b o t h s i t e s . T h i s p a t t e r n h e l d f o r a l l woody s p e c i e s (paper b i r c h , H o l o d i s c u s d i s c o l o r , T h u i a p l i c a t a , Tsuga 147 h e t e r o p h y l l a ) , e xcept Rubus a t t h e Cheekye Loop and Pseudotsuqa  m e n z i e s i i a t M a l a s p i n a . The dominance o f o n l y a few s p e c i e s i n t h e seed r a i n , as ob s e r v e d h e r e , i s a common f i n d i n g i n f o r e s t e d ( A r c h i b o l d 1980; E v e r e t t and Sharrow 1983), g r a s s l a n d ( R a b i n o w i t z and Rapp 1980) and o l d f i e l d ( M o r r i s e t a l . 1986) env i r o n m e n t s . The d i f f e r e n t m e t h o d o l o g i e s used i n seed r a i n s t u d i e s c o m p l i c a t e t h e comparison o f t h e r e s u l t s o f o t h e r s t u d i e s w i t h t h e d a t a p r e s e n t e d here (Table 4.6). Some r e s e a r c h e r s counted o n l y g e r m i n a b l e seeds, o r sampled f o r o n l y p a r t o f t h e y e a r . K e l l m a n ' s (1974) seed r a i n s t u d y was conducted a t t h e U n i v e r s i t y o f B r i t i s h Columbia R e s e a r c h F o r e s t . The p l a n t communities f o r which he e s t i m a t e d t h e seed r a i n were a mature (102 y e a r - o l d ) w e s t e r n r e d c e d a r / w e s t e r n h e m l o c k / D o u g l a s - f i r f o r e s t and an 8-y e a r - o l d s u c c e s s i o n a l community on an a d j a c e n t c l e a r c u t s i t e . The v e g e t a t i o n was, i n g e n e r a l , s i m i l a r t o t h a t i n which t h e p r e s e n t s t u d y was conducted. Comparison w i t h h i s s t u d y w i l l be emphasized. In t h i s s t u d y , t h e number o f s p e c i e s t r a p p e d each y e a r v a r i e d g r e a t l y (Tables 4.1, 4.2). S p e c i e s r i c h n e s s ( n a t i v e s p e c i e s o n l y ) was g r e a t e r on t h e r i g h t s - o f - w a y t h a n i n t h e f o r e s t s . K e l l m a n (1974) a l s o found seed r a i n s p e c i e s r i c h n e s s t o v a r y over t i m e , and t o be h i g h e r i n t h e c u t o v e r community (31 taxa) t h a n i n t h e a d j a c e n t mature f o r e s t (15 t a x a ) . T a b l e 4.6 A comparison o f seed r a i n s t u d i e s i n f o r e s t e d e n v i r o n m e n t s . Location Trap type L Number Trapping i n t e r v a l Seeds Number Seeds Source vegetation type area (cm2) of traps and duration counted of species per m2 Wagner (1965) New York deciduous forest (irradiated) S t i c k y 100.0 83 1-2 weeks; 2 4-month periods t o t a l 13 166 Kellman (1974) B r i t i s h Columbia mature Douglas-fir f o r e s t 8 year-old successional community S o i l 78.5 44 64 11.5-15 months; 3 years germinable ( f i e l d + lab) 3-16-10 •21 15-46 1 245-641 1 A r c h i b o l d (1980) Saskatchewan burned mixed-wood f o r e s t S o i l 300.0 63 12 months; 2 years germinable ( f i e l d + lab) + t o t a l 11 344-898 2 Everett t Sharrow (1983) Nevada (3 aspects) Pinyon-juniper woodland unharvested and harvested stands Screen 80.0 ? 2-3 weeks; growing seasons of 2 years f i l l e d 8-10-•13 12 13-27 3 193-318 3 This study B r i t i s h Columbia (2 s i t e s ) second growth D o u g l a s - f i r successional vegetation Screen 1352.0 12 30 1 month; 2 years germinable (greenhouse) + t o t a l 11-23-22 26 335-3691 4 (29-1296) 178-710 4 (36-135) 1 range over 3 ye a r s 2 range over 2 y e a r s 3 because t h e number o f t r a p s i n each t r e a t m e n t (aspect x h a r v e s t e d / u n h a r v e s t e d x s o i l s u r f a c e m i c r o s i t e ) was not g i v e n , t h e s e v a l u e s f o r mean seeds/m^ (data f o r t h e 3 a s p e c t s and 3 s o i l s u r f a c e m i c r o s i t e s combined) s h o u l d be c o n s i d e r e d c r u d e e s t i m a t e s . 4 range over 2 ye a r s a t 2 s i t e s , n a t i v e s p e c i e s o n l y ; t o t a l seeds (germinable s e e d s ) . 149 K e l l m a n (1974) found t h a t t h e seed f a l l over a t h r e e y e a r s a m p l i n g p e r i o d was c o n s i s t e n t l y l o w e r i n t h e f o r e s t (15, 46, and 17 seeds/m 2) t h a n i n t h e s u c c e s s i o n a l community (641, 571, and 245 seeds/m 2). The v a l u e s f o r t h e f o r e s t seed r a i n i n t h i s s t u d y , 309-3693 seeds/m 2, a r e 1 t o 2 o r d e r s o f magnitude g r e a t e r t h a n t h o s e r e p o r t e d i n Ke l l m a n (1974), w h i l e v a l u e s f o r t h e s u c c e s s i o n a l communities, 226-1150 seeds/m 2, are s i m i l a r t o t h o s e r e p o r t e d by K e l l m a n . The d i s p a r i t y between Kellman's (1974) r e s u l t s and t h o s e p r e s e n t e d here has a t l e a s t t h r e e s o u r c e s . F i r s t , K e l l m a n ' s t r a p p i n g i n t e r v a l was l o n g (11.5-15 months), and low seed numbers c o u l d be t h e r e s u l t o f seed p r e d a t i o n and/or seed m o r t a l i t y . Second, K e l l m a n c o u n t e d o n l y g e r m i n a b l e seed, and i t i s p o s s i b l e t h a t some s e e d l i n g s g e r m i n a t e d i n t h e f i e l d and d i e d b e f o r e t h e t r a p s were c o l l e c t e d : h i s seed count c o u l d r e f l e c t , i n p a r t , t h e s u i t a b i l i t y o f t h e t r a p m i c r o s i t e f o r s e e d l i n g e s t a b l i s h m e n t o r s t o r a g e . T h i s k i n d o f assessment a l s o o b s c u r e s d i f f e r e n c e s i n t h e q u a l i t y ( i . e . , g e r m i n a b i l i t y ) and s i z e o f t h e seed c r o p . F i n a l l y , t h e s p e c i e s c o m p o s i t i o n and age o f t h e v e g e t a t i o n c o n t r i b u t i n g t o t h e seed r a i n d i f f e r e d . Because t h e t r a p s were checked monthly, a d e t a i l e d a n a l y s i s o f s p e c i e s phenology (Wagner 1965; R a b i n o w i t z and Rapp 1980; M o r r i s e t a_l. 1986) was not p o s s i b l e . N e v e r t h e l e s s , t h e monthly c o l l e c t i o n i n t e r v a l over t h e two-year t r a p p i n g p e r i o d p e r m i t t e d comparison o f t h e annual v a r i a t i o n o f d i s p e r s a l w i t h i n , and s e a s o n a l p a t t e r n o f d i s p e r s a l between, t a x a . V a r i a t i o n i n numbers o f t r a p p e d seeds between y e a r s was c o n s i d e r a b l e : f o r a l l 150 t a x a , more p r o p a g u l e s were d i s p e r s e d i n t h e 1985-1986 seed y e a r t h a n i n t h e 1984-1985 seed y e a r . S e e d - b e a r i n g p l a n t s commonly r e g a r d e d as dominant or i m p o r t a n t i n e a r l y s u c c e s s i o n a l p l a n t communities i n c o a s t a l B.C. i n c l u d e t h e t r e e r e d a l d e r (Alnus r u b r a ) , t h e shrubs Rubus  p a r v i f l o r u s and Rubus l e u c o d e r m i s , and t h e herbaceous s p e c i e s A n a p h a l i s m a r q a r i t a c e a , S e n e c i o s y l v a t i c u s , M v c e l i s m u r a l i s , H i e r a c i u m a l b i f l o r u m , and E p i l o b i u m a n q u s t i f o l i u m . Of t h e s e s p e c i e s , S. s y l v a t i c u s was absent from t h e seed r a i n , and E. a n q u s t i f o l i u m and t h e o t h e r herbaceous s p e c i e s l i s t e d above a r e c o n s p i c u o u s by t h e i r low c o n t r i b u t i o n t o i t . K e l l m a n (1974) r e p o r t e d much h i g h e r numbers f o r a l l o f t h e s e s p e c i e s i n an 8 y e a r - o l d s u c c e s s i o n a l community, and A r c h i b o l d (1980) found t h a t E p i l o b i u m a n q u s t i f o l i u m dominated t h e seed r a i n on a 1 y e a r - o l d burned s i t e . The low abundance o f t h e s e s p e c i e s i n t h i s s t u d y may r e f l e c t a s m a l l seed s o u r c e downwind o f t h e s t u d y s i t e s , spot (not b r o a d c a s t ) b u r n i n g , and c o m p e t i t i o n from t h e seeded g r a s s e s and legumes f o r g e r m i n a t i o n and e s t a b l i s h m e n t s i t e s . F o r t h e w i n d - d i s p e r s e d s p e c i e s , i t i s u n c l e a r whether t h e t r a p p i n g p a t t e r n o b s e r v e d was due t o t h e wind b e i n g f u n n e l l e d a l o n g t h e r i g h t s - o f - w a y (by t h e 15-30 m t a l l t r e e s on e i t h e r s i d e ) , o r whether winds were not d e f l e c t e d by t h e uncut v e g e t a t i o n . I f t h e former, t h i s c o u l d e x p l a i n t h e low seed count of composite s p e c i e s i n t h e f o r e s t s , and t h e low count of t r e e seeds on t h e r i g h t s - o f - w a y . I f t h e l a t t e r , and i f winds i n a n o r t h - s o u t h d i r e c t i o n were' common, i t would i m p l y t h a t d i s p e r s a l d i s t a n c e s were v e r y s h o r t . 151 4.5 C o n c l u s i o n s As f o r e s t v e g e t a t i o n management becomes more i n t e n s i v e , i n f o r m a t i o n i s needed t o c l a r i f y our u n d e r s t a n d i n g o f t h e response o f t h e v e g e t a t i o n o f a s i t e t o c l e a r i n g a t d i f f e r e n t t i m e s o f t h e y e a r , and t o h e l p i n t h e p r e d i c t i o n o f t h e s p e c i e s c o m p o s i t i o n and r e c r u i t m e n t i n t o t h e p l a n t communities which d e v e l o p a f t e r d i s t u r b a n c e . The t e m p o r a l component of seed d i s p e r s a l i s an e x p r e s s i o n o f t h e p h e n o l o g i e s o f t h o s e s p e c i e s which comprise t h e f l o r a . Observed p a t t e r n s o f s u c c e s s i o n may be i n f l u e n c e d by t h e season o f t h e d i s t u r b a n c e event ( l o g g i n g , s l a s h b u r n i n g ) : t h e s p e c i e s which are d i s p e r s e d i m m e d i a t e l y a f t e r a d i s t u r b a n c e may be a b l e t o u t i l i z e t h e d i s t u r b e d s i t e more e f f e c t i v e l y t h a n t h o s e d i s p e r s e d b e f o r e t h e d i s t u r b a n c e . Red a l d e r seeded p r i m a r i l y i n t h e months of November t o F e b r u a r y . I t s seeds are r e p o r t e d t o r e t a i n t h e i r v i a b i l i t y f o r a t l e a s t 10 months (Bormann 1983) . I f e x c l u s i o n o f t h i s s p e c i e s from d i s t u r b e d l a n d i s d e s i r e d , c l e a r i n g a s i t e a f t e r t h e d i s p e r s a l o f r e d a l d e r f r u i t s (thus b u r y i n g , and perhaps d e s t r o y i n g , t h e d i s p e r s e d seeds) might be an e f f e c t i v e s t r a t e g y . Granstrom and F r i e s (1985) suggest t h a t , i n Swedish f o r e s t s , B e t u l a pubescens and B. v e r r u c o s a t r e e s be f e l l e d a few y e a r s b e f o r e h a r v e s t i n g t o e l i m i n a t e t h e s o u r c e o f s h o r t - l i v e d b i r c h seeds. Throughout t h i s s t u d y , seeds of r e d a l d e r were f a r more abundant th a n t h o s e o f c o n i f e r s . The removal of seed t r e e s t o reduce r e d a l d e r r e g e n e r a t i o n may be u s e f u l . 152 C h apter 5 Bud Bank, Seed Bank, Seed R a i n , and E a r l y S u c c e s s i o n i n F o r e s t e d Regions o f C o a s t a l B r i t i s h Columbia 5.1 I n t r o d u c t i o n I n her problem a n a l y s i s o f f o r e s t v e g e t a t i o n management i n B r i t i s h Columbia, Conard (1984) i d e n t i f i e d t e n f i e l d s o f r e s e a r c h t h a t she f e l t s h o u l d r e c e i v e h i g h p r i o r i t y . Among t h e s e r e s e a r c h p r i o r i t i e s were (1) t h e a u t e c o l o g y o f s p e c i e s competing w i t h c r o p t r e e s , (2) t h e impact o f d i f f e r e n t methods of s i t e p r e p a r a t i o n on r e v e g e t a t i o n , and (3) t h e p r e d i c t i o n o f s u c c e s s i o n a l p a t t e r n s . These t h r e e t o p i c s a re i n t e r - r e l a t e d . Fundamental t o e f f e c t i v e v e g e t a t i o n management i n any c o n t e x t i s an u n d e r s t a n d i n g of t h e response o f components o f t h e f l o r a t o t h e v a r i o u s t e c h n i q u e s and p r o c e d u r e s employed i n c r o p h a r v e s t i n g , s i t e p r e p a r a t i o n and management. Knowing t h e b i o l o g y and t h e mechanisms o f p e r s i s t e n c e o r i n v a s i o n employed by key s p e c i e s w i l l h e l p us t o u n d e r s t a n d t h e response o f t h e s e s p e c i e s t o d i s t u r b a n c e and may a l l o w us t o . p r e d i c t t h e co u r s e o f s u c c e s s i o n . Knowledge and u n d e r s t a n d i n g o f t h i s k i n d c o u l d change t h e emphasis of v e g e t a t i o n management from c o r r e c t i v e t o p r e v e n t i v e measures. The s p e c i f i c o b j e c t i v e s and t h e t a r g e t s p e c i e s o f t r a n s m i s s i o n l i n e r i g h t - o f - w a y v e g e t a t i o n management d i f f e r from t h o s e o f t i m b e r p r o d u c t i o n . Both are concerned w i t h c o n t r o l l i n g t h e growth o f s e r a i d e c i d u o u s t r e e s p e c i e s , however. These t r e e s can t h r e a t e n r e l i a b l e power t r a n s m i s s i o n because o f t h e i r 153 p o t e n t i a l t o grow i n t o c o n t a c t w i t h t h e t r a n s m i s s i o n l i n e s , t h e r e b y s h o r t - c i r c u i t i n g t h e e l e c t r i c a l c o n d u c t o r s and c a u s i n g power outages. These s p e c i e s a l s o compete f o r r e s o u r c e s w i t h c r o p t r e e s i n t h e case of t i m b e r p r o d u c t i o n . Many shrub s p e c i e s which are c o n s i d e r e d weeds i n t h e e a r l y s t a g e s o f f o r e s t r e g e n e r a t i o n are i d e a l as r i g h t - o f - w a y c o v e r p r e c i s e l y because of t h e i r a b i l i t y t o i n t e r f e r e w i t h t h e e s t a b l i s h m e n t and growth of t r e e s p e c i e s . B r i t i s h Columbia Hydro and Power A u t h o r i t y has a p p r o x i m a t e l y 60,000 km o f t r a n s m i s s i o n l i n e r i g h t s - o f - w a y under i t s j u r i s d i c t i o n , 80% o f which l i e s i n f o r e s t e d r e g i o n s o f t h e p r o v i n c e . B.C. Hydro has d e f i n e d f o u r s t a n d a r d s f o r c l e a r i n g f o r e s t e d l a n d p r i o r t o t r a n s m i s s i o n l i n e c o n s t r u c t i o n . S tandards A and B are s e l e c t i v e c u t s which are d i f f e r e n t i a t e d on t h e b a s i s o f c r i t e r i a f o r t h e removal of l o g g i n g d e b r i s . S tandards C and D are c l e a r c u t s which a r e groomed and seeded t o g r a s s e s , and are d i f f e r e n t i a t e d on t h e b a s i s of c r i t e r i a f o r stump rem o v a l . O f t e n , i n s u f f i c i e n t 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 b i o l o g y o f t h e s p e c i e s which comprise t h e v e g e t a t i o n t h a t i s c u t . B l a n k e t c l e a r c u t s are sometimes a p p l i e d where s e l e c t i v e c u t s would be a p p r o p r i a t e : s e l e c t i v e c u t s would l e a v e more a c c e p t a b l e r e s i d u a l v e g e t a t i o n . The s p e c i f i c q u e s t i o n s a d d r e s s e d i n t h i s s t u d y were (1) what are t h e r e l a t i v e c o n t r i b u t i o n s o f r e s p r o u t i n g or r e s i d u a l v e g e t a t i o n , v i a b l e seeds s t o r e d i n t h e s o i l , and d i s p e r s e d seeds t o t h e r e c r u i t m e n t o f s p e c i e s i n t o s c a r i f i e d p l o t s ? (2) How do i n d i v i d u a l s p e c i e s respond t o d i s t u r b a n c e i n terms of r e c o v e r y 154 and/or r e i n v a s i o n ? The s t u d y was d e s i g n e d t o t e s t t h e f o l l o w i n g h y p o t h e s i s : knowing p l a n t community s p e c i e s c o m p o s i t i o n , d i s t u r b a n c e t y p e and i n t e n s i t y , and t h e s p e c i e s c o m p o s i t i o n o f t h e seed bank and seed r a i n , e a r l y s e r a i p l a n t community s p e c i e s c o m p o s i t i o n can be p r e d i c t e d . 5.2 Methods 5.2.1 The st u d y s i t e s The r e s e a r c h was conducted on two t r a n s m i s s i o n l i n e r i g h t s -of-way i n t h e c o a s t a l w e s t e r n hemlock zone of B r i t i s h Columbia. The Cheekye Loop (10 km n o r t h o f Squamish) and M a l a s p i n a (30 km nor t h w e s t o f S e c h e l t ) 500 kV t r a n s m i s s i o n l i n e r i g h t s - o f - w a y were c l e a r e d between September 1980 and December 1981. At t h e ti m e o f c l e a r i n g , t h e a d j a c e n t f o r e s t s were a p p r o x i m a t e l y 26 and 39 y e a r s o l d , r e s p e c t i v e l y . B o t h f o r e s t s had a t t a i n e d canopy c l o s u r e and were 15-30 m t a l l . S e v e r e l y d i s t u r b e d a r e a s on b o t h r i g h t s - o f - w a y were seeded t o a mix o f agronomic g r a s s e s and legumes ( i n c l u d i n g F e s t u c a r u b r a , Poa p r a t e n s i s , Phleum  p r a t e n s e , L o l i u m perenne, T r i f o l i u m hybridum, and T. repens) a t a r a t e o f a p p r o x i m a t e l y 28 kg/ha i n 1982 t o c o n t r o l e r o s i o n and impede t h e e s t a b l i s h m e n t o f r e d a l d e r (Alnus r u b r a ) . 5.2.2 V e g e t a t i o n - t h e bud bank The s p e c i e s c o m p o s i t i o n and numbers o f p r o p a g u l e s i n t h e bud bank were not q u a n t i f i e d , but a census o f t h o s e s p e c i e s p r e s e n t a d j a c e n t t o t h e s c a r i f i e d p l o t s (30 p e r r i g h t - o f - w a y ) 155 gave i n f o r m a t i o n (presence/absence) about t h o s e s p e c i e s which were a v a i l a b l e and c a p a b l e o f v e g e t a t i v e r e c o v e r y o r i n v a s i o n . The v e g e t a t i o n a d j a c e n t t o t h e s c a r i f i e d p l o t s was a s s e s s e d d u r i n g t h e summer of 1984. Sample p l o t s (3 X 3 m) were e s t a b l i s h e d i m m e d i a t e l y a d j a c e n t t o t h e s c a r i f i e d p l o t s i n a r e a s of homogeneous v e g e t a t i o n and topography. The methods employed i n t h e s a m p l i n g and c l a s s i f i c a t i o n o f t h e v e g e t a t i o n a r e e x p l a i n e d i n Chapter 2. 5.2.3 The seed bank Seed bank s a m p l i n g and g e r m i n a t i o n methods are d e s c r i b e d i n d e t a i l i n Chapter 3. E s t i m a t e s o f t h e r e s e r v e o f b u r i e d v i a b l e seeds a s s o c i a t e d w i t h t h e s c a r i f i e d p l o t s were o b t a i n e d from s o i l samples c o l l e c t e d between March 23-30, 1984. The samples, l o c a t e d i n a greenhouse, were s t i r r e d once t o promote g e r m i n a t i o n o f t h o s e seeds which had been b u r i e d . G e r m i n a t i o n was f o l l o w e d f o r 23.5 weeks. 5.2.4 The seed r a i n D e t a i l s on t h e methods employed and r e s u l t s o b t a i n e d a r e p r e s e n t e d i n Chapter 4. The seed t r a p s were l o c a t e d i m m e d i a t e l y a d j a c e n t t o t h e s c a r i f i e d p l o t s . Only i m p o r t a n t s p e c i e s w i l l be d i s c u s s e d i n t h i s c h a p t e r . 156 5.2.5 S c a r i f i e d p l o t s T h i r t y 1 m 2 p l o t s were s c a r i f i e d i n March 1984 on each of t h e two t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . The s c a r i f i e d p l o t s were l o c a t e d a l o n g t h e t r a n s e c t s , i n a r e a s o f v i s u a l l y homogeneous v e g e t a t i o n and topography, a d j a c e n t t o t h e seed t r a p s ( F i g u r e s 5.1 and 5.2). S c a r i f i c a t i o n e n t a i l e d t h e removal of t h e f o r e s t f l o o r , where p r e s e n t , and a l l s t a n d i n g l i v e o r dead v e g e t a t i o n by s c r a p i n g t h e p l o t s w i t h a s h o v e l o r mattock so t h a t t h e m i n e r a l s o i l was exposed. O b s e r v a t i o n s o f t h e r e c o l o n i z a t i o n o f t h e s c a r i f i e d p l o t s were made i n August of 1984, 1985, and 1986. The f r e q u e n c y o f o c c u r r e n c e o f g e r m i n a n t s and v e g e t a t i v e l y r e s p r o u t i n g i n d i v i d u a l s was a s s e s s e d . From t h e s e d a t a , t h e r e l a t i v e i m p o r t a n c e o f t h e bud bank, seed bank, and seed r a i n " s t r a t e g i e s " was e s t i m a t e d f o r i m p o r t a n t s p e c i e s . 5.3 R e s u l t s 5.3.1 V e g e t a t i o n - t h e bud bank Two p l a n t a s s o c i a t i o n s , d e s c r i b e d i n d e t a i l i n C hapter 2, dominated t h e r i g h t s - o f - w a y . The P t e r i d i u m - G a u l t h e r i a a s s o c i a t i o n was l o c a t e d on x e r i c t o s u b - x e r i c r i d g e c r e s t s and r o c k y prominences, and was r e l a t i v e l y l e s s d i s t u r b e d ( c l e a r i n g s t a n d a r d s A/B) because of t o p o g r a p h i c r e s t r i c t i o n s on machine a c c e s s . The Rubus - P t e r i d i u m a s s o c i a t i o n was s i t u a t e d on sub-mesic t o mesic mid- t o l o w e r - s l o p e s , and was r e l a t i v e l y more 157 • seed trap • scarified plot |~~] vegeta t ion plot F i g u r e 5.1 A schematic diagram of the arrangement of v e g e t a t i o n p l o t s , seed t r a p s , and s c a r i f i e d p l o t s e s t a b l i s h e d on the r i g h t s -of-way. Only 2 of 6 t r a n s e c t s are i l l u s t r a t e d . 158 Figure 5.2 Examples of the s c a r i f i e d p l o t s (foreground) w i t h adjacent seed t r a p s . d i s t u r b e d ( c l e a r i n g s t a n d a r d s C/D). W i t h i n each o f t h e a s s o c i a t i o n s , two s u b a s s o c i a t i o n s were i d e n t i f i e d . The G a u l t h e r i a s u b a s s o c i a t i o n was l e s s d i s t u r b e d t h a n t h e P o l y t r i c h u m s u b a s s o c i a t i o n . S i m i l a r l y , 1 t h e P t e r i d i u m s u b a s s o c i a t i o n was l e s s d i s t u r b e d , and/or m o i s t e r t h a n t h e Phleum s u b a s s o c i a t i o n . See Chapter 2 f o r a 'more d e t a i l e d d i s c u s s i o n o f t h e s e r e s u l t s . The d i s t r i b u t i o n o f t h e Cheekye Loop p l o t s ( a d j a c e n t t o t h e s c a r i f i e d p l o t s ) among t h e f o u r s u b a s s o c i a t i o n s was 8 G a u l t h e r i a , 14 P o l y t r i c h u m , and 8 P t e r i d i u m , w h i l e t h a t o f t h e M a l a s p i n a p l o t s was 12 P o l y t r i c h u m and 18 Phleum. These d i s t r i b u t i o n s r e f l e c t two main p o i n t s : t h e topography as i t i n f l u e n c e d machine a c c e s s d u r i n g c l e a r i n g , and t h e c r i t e r i o n used f o r p o s i t i o n i n g o f t h e t r a n s e c t s (ease of a c c e s s f o r c h e c k i n g t h e seed t r a p s ) . T a ble 5.1 l i s t s t h e f r e q u e n c y o f o c c u r r e n c e o f t h o s e s p e c i e s c a p a b l e of r e - e s t a b l i s h i n g v e g e t a t i v e l y f o l l o w i n g d i s t u r b a n c e , and t h e r e f o r e c o n t r i b u t i n g t o t h e bud bank, i n t h e v e g e t a t i o n p l o t s a d j a c e n t t o t h e s c a r i f i e d p l o t s . A l t h o u g h a s p e c i e s may have been e s t a b l i s h e d i m m e d i a t e l y a d j a c e n t t o t h e s c a r i f i e d p l o t , i t i s u n c e r t a i n whether t h a t s p e c i e s was a l s o p r e s e n t w i t h i n t h e 1 m^  p l o t b e f o r e s c a r i f i c a t i o n , and t h a t o t h e r s p e c i e s were n o t . I f t h e 1 m^  p l o t s . h a d been censused b e f o r e s c a r i f i c a t i o n ( i n March 1984), some s p e c i e s c o u l d have been m i s s e d because t h e y were dormant a t t h a t t i m e . 160 Table 5.1 Number of p l o t s (out o f 30), i m m e d i a t e l y a d j a c e n t t o t h e s c a r i f i e d p l o t s , i n which a p o t e n t i a l l y v e g e t a t i v e l y r e -e s t a b l i s h i n g s p e c i e s o c c u r r e d , a t each s t u d y s i t e , r = r h i z o m a t o u s , sp = s p r o u t i n g from r o o t c o l l a r o r stump, s = s u c k e r i n g . S p e c i e s Mechanism Cheekye Loop M a l a s p i n a A c e r macrophyllum sp 4 1 A l n u s r u b r a sp 13 27 A n a p h a l i s m a r q a r i t a c e a r , sp 16 9 Apocvnum a n d r o s a e m i f o l i u m r 2 B e t u l a p a p v r i f e r a sp 17 Carex spp. sp 2 3 C i r s i u m v u l q a r e sp 1 3 E p i l o b i u m a n q u s t i f o l i u m r , sp 17 13 E p i l o b i u m w a t s o n i i r , sp 1 7 Equisetum p r a t e n s e r 2 F r a q a r i a v i r q i n i a n a sp 2 G a u l t h e r i a s h a l l o n r , sp,s 21 19 H o l o d i s c u s d i s c o l o r sp 9 17 L i n n a e a b o r e a l i s sp 2 1 Mahonia n e r v o s a r , sp 12 11 P a x i s t i m a m v r s i n i t e s sp 2 Populus t r i c h o c a r p a s, sp 3 Prunus e m a r q i n a t a sp 4 14 P t e r i d i u m a q u i l i n u m r 24 22 R i b e s sanquineum sp 2 5 Rosa qymnocarpa sp 2 4 Rubus l e u c o d e r m i s sp 9 13 R. p a r v i f l o r u s r 14 12 R. s p e c t a b i l i s r 7 5 R. u r s i n u s sp 17 14 S a l i x b e b b i a n a sp 1 2 S a l i x s c o u l e r i a n a sp 6 Sambucus racemosa r , sp 2 1 S p i r a e a d o u q l a s i i sp 6 7 T r i e n t a l i s l a t i f o l i a sp 9 5 V a c c i n i u m p a r v i f o l i u m sp 8 6 * from H i t c h c o c k and C r o n q u i s t (1973), H a e u s s l e r and Coates (1986), S t i c k n e y (1986), and p e r s o n a l o b s e r v a t i o n s . 161 5 . 3 . 2 The seed bank A t o t a l o f 27 s p e c i e s (seeded s p e c i e s and mosses excluded) emerged from t h e Cheekye Loop s c a r i f i e d p l o t seed bank samples, w h i l e 21 were o b s e r v e d i n t h e M a l a s p i n a samples (Table 5 . 2 ) . Most o f t h e s p e c i e s were p r e s e n t i n l e s s t h a n 6 (20%) of t h e samples from each l o c a t i o n . The d e n s i t y o f seeds p e r square meter f o r s e l e c t e d s p e c i e s (those which were l a t e r o b s e r v e d t o r e g e n e r a t e from seed on t h e s c a r i f i e d p l o t s ) i s g i v e n i n Table 5 . 3 . The dominant member of t h e seed bank a t b o t h s i t e s was Se n e c i o s y l v a t i c u s : no o t h e r s p e c i e s approached i t s f r e q u e n c y (80-90%) or abundance (800 seeds m~ 2). G a u l t h e r i a s h a l l o n and A n a p h a l i s m a r q a r i t a c e a were more f r e q u e n t l y found a t t h e Cheekye Loop t h a n a t M a l a s p i n a . Seeds o f G. s h a l l o n were found almost e x c l u s i v e l y i n t h e f o r e s t f l o o r (Chapter 3): t h i s l a y e r was absent from t h e M a l a s p i n a sample p l o t s b e f o r e s c a r i f i c a t i o n , but was p r e s e n t i n 63% o f t h e Cheekye Loop sample p l o t s . Seeds o f Rubus spp. were absent from t h e M a l a s p i n a s c a r i f i e d p l o t seed bank samples, b u t were p r e s e n t i n seed bank samples t a k e n f o r a stu d y comparing seed banks o f d i f f e r e n t ecosystems (Chapter 3 ) . Sonchus o l e r a c e u s was b o t h more f r e q u e n t and abundant a t t h e Cheekye Loop, and B e t u l a p a p y r i f e r a ( t r e e s , and t h e r e f o r e seeds) o c c u r r e d a t t h e Cheekye Loop but not a t M a l a s p i n a . 162 Table 5.2 Number o f germ i n a n t s o f n a t i v e and n a t u r a l i z e d s p e c i e s emerging from t h e 30 s c a r i f i e d p l o t seed bank samples c o l l e c t e d a t each s t u d y s i t e . Frequency o f o c c u r r e n c e (or co n s t a n c y , out o f 30) i s g i v e n i n p a r e n t h e s e s . S p e c i e s r e p r o d u c i n g by s p o r e s , and seeded g r a s s e s and legumes, a r e e x c l u d e d . (C) = p l a n t s o b s e r v e d at t h e Cheekye Loop o n l y ; (M) = M a l a s p i n a o n l y . S p e c i e s Cheekye Loop M a l a s p i n a A g r o s t i s spp. 145 (16) 26 (13) A i r a p r a t e n s e (M) 1 (1) A l n u s r u b r a 1 (1) 7 (1) A n a p h a l i s m a r g a r i t a c e a 168 (11) 5 (4) Aruncus d i o i c u s (C) 2 (2) A t h y r i u m f i l i x - f e m i n a 199 (12) 19 (4) B e t u l a p a p y r i f e r a (C) 65 (13) Carex spp. 22 (4) 3 (1) C i r s i u m v u l g a r e 3 (1) C o l l o m i a h e t e r o p h y l l a (M) 47 (2) D a n t h o n i a s p i c a t a (C) 8 (1) E p i l o b i u m a n g u s t i f o l i u m 1 (1). E p i l o b i u m minimum 3 (2) E p i l o b i u m w a t s o n i i 14 (4) 15 (5) F r a g a r i a v i r g i n i a n a (C) 1 (1) Galium t r i f l o r u m 32 (2) G a u l t h e r i a s h a l l o n 80 (16) 180 (2) H o l o d i s c u s d i s c o l o r 6 (5) Juncus spp. 1 (1) L u z u l a spp. 2 (2) 117 (4) M v c e l i s m u r a l i s 3 (2) Prunus e m a r g i n a t a 1 (1) P t e r i d i u m a q u i l i n u m 130 (7) R i b e s sanguineum • 1 (1) Rubus spp. 6 (6) Sambucus racemosa 1 (1) S e n e c i o s y l v a t i c u s 480 (27) 483 (24) Sonchus o l e r a c e u s 18 (7) 3 (1) S p i r a e a d o u g l a s i i 8 (4) 2 (2) Tsuga h e t e r o p h y l l a 1 (1) 1 (1) Typha l a t i f o l i a 3 (3) V i o l a spp. 1 (1) Number o f s p e c i e s 27 21 163 Table 5.3 Number o f seeds p e r square meter ± s t a n d a r d e r r o r f o r s e l e c t e d i m p o r t a n t s p e c i e s i n t h e s c a r i f i e d p l o t seed bank samples. (C) = p l a n t s o b s e r v e d a t t h e Cheekye Loop o n l y . S p e c i e s Cheekye Loop M a l a s p i n a A n a p h a l i s m a r g a r i t a c e a  B e t u l a p a p y r i f e r a (C) G a u l t h e r i a s h a l l o n  Rubus spp. Se n e c i o s y l v a t i c u s  Sonchus o l e r a c e u s 280 108 133 10 800 ± ± ± ± + 176 52 55 4 287 8 ± 4 30 ± 19 300 ± 298 0 ± + 805 5 335 5 164 5.3.3 The seed r a i n T a ble 5.4 c o n t a i n s seed r a i n d a t a (seeds p e r square meter) f o r s e l e c t e d s p e c i e s . The s p e c i e s are t h o s e which are i m p o r t a n t e a r l y s u c c e s s i o n a l s p e c i e s i n ; c o a s t a l B.C. ( c o n s i d e r e d t o be weeds i n t h e c o n t e x t o f f o r e s t r e g e n e r a t i o n but a c c e p t a b l e on t r a n s m i s s i o n l i n e r i g h t s - o f - w a y ) and f o r e s t t r e e (crop) s p e c i e s . A d e t a i l e d d e s c r i p t i o n and a n a l y s i s o f t h e seed r a i n o b s e r v e d on t h e two r i g h t s - o f - w a y i s g i v e n i n Chapter 4. The seed r a i n i n t h e second y e a r was g r e a t e r t h a n i n t h e f i r s t . S e n e c i o s y l v a t i c u s . however, was absent b o t h y e a r s . G a u l t h e r i a s h a l l o n and A n a p h a l i s m a r q a r i t a c e a seeds were more abundant a t t h e Cheekye Loop, w h i l e t h o s e o f H o l o d i s c u s  d i s c o l o r , A. r u b r a and Tsuga h e t e r o p h y l l a were more abundant a t M a l a s p i n a . There were few seeds of t h e c o n i f e r s Pseudotsuga  m e n z i e s i i , T h u i a p l i c a t a and Tsuga h e t e r o p h y l l a . The abundance of Rubus spp. seeds was a p p r o x i m a t e l y e q u a l a t t h e two s t u d y s i t e s . 5.3.4 R e v e g e t a t i o n o f s c a r i f i e d p l o t s 5.3.4.1 V e g e t a t i v e r e s p r o u t i n g A few p l o t s (1 a t t h e Cheekye Loop, 5 a t M a l a s p i n a ) were " l o s t " over t h e o b s e r v a t i o n p e r i o d due t o e x t e n s i v e i n v a s i o n by t h e seeded grass/legume mix, which o b s c u r e d t h e p l o t b o u n d a r i e s , or due t o t h e f a d i n g and decay of f l a g g i n g t a p e ( t i e d t o a shrub or t r e e ) which was used t o mark one c o r n e r o f t h e p l o t s . The 165 Tab l e 5.4 Mean number o f d i s p e r s e d seeds t r a p p e d p e r square meter p e r y e a r ± s t a n d a r d e r r o r , f o r s e l e c t e d n a t i v e s p e c i e s , on t h e r i g h t s - o f - w a y a t t h e two s t u d y s i t e s . Data a r e c o r r e c t e d f o r m i s s i n g t r a p s . (C) = p l a n t s o b s e r v e d a t t h e Cheekye Loop o n l y . S p e c i e s Cheekye Loop M a l a s p i n a 84-85 85-86 84-85 85-86 A l n u s r u b r a 8±2 2 9±9 4 6±7 69±17 A n a p h a l i s m a r q a r i t a c e a 9±5 112±44 11±8 15±10 B e t u l a p a p v r i f e r a (C) 4±1 36±5 G a u l t h e r i a s h a l l o n 7 0+45 33±30 2±1 0 H o l o d i s c u s d i s c o l o r 37±17 62±35 66±33 217±85 Pseudotsuqa m e n z i e s i i + 4±1 + 2±1 Rubus S O P . 17±6 325±207 23±13 295±182 Th u i a p l i c a t a + 11±8 2±1 8±2 Tsuqa h e t e r o p h y l l a 3±1 17±3 2±1 34±4 + = l e s s t h a n 1 seed/m 166 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 i n t h e s c a r i f i e d p l o t s was used t o d e s c r i b e changes over t h e c o u r s e o f t h e s t u d y . Mean s p e c i e s s i g n i f i c a n c e , based on t h o s e p l o t s i n which t h e s p e c i e s o c c u r r e d , was a s s e s s e d f o r v e g e t a t i v e l y r e p r o d u c i n g s p e c i e s . S e v e r a l s p e c i e s were o b s e r v e d t o become e s t a b l i s h e d i n t h e s c a r i f i e d p l o t s by v e g e t a t i v e means (Table 5.5), but most o f them were r a r e . G a u l t h e r i a s h a l l o n , P t e r i d i u m a q u i l i n u m , and Rubus u r s i n u s were t h e most i m p o r t a n t v e g e t a t i v e l y r e p r o d u c i n g s p e c i e s . The y e a r l y p a t t e r n o f f r e q u e n c y and mean s i g n i f i c a n c e o f t h e s e s p e c i e s i n t h e s c a r i f i e d p l o t s a re d i s p l a y e d i n F i g u r e 5.3. G a u l t h e r i a s h a l l o n responded t o p l o t s c a r i f i c a t i o n w i t h o n l y a minor d e c l i n e i n f r e q u e n c y , d e s p i t e removal o f t h e f o r e s t f l o o r . The f o r e s t f l o o r a t t h e s e s i t e s was l e s s t h a n 5 cm t h i c k , and rhizomes o f t h i s s p e c i e s were a l s o l o c a t e d i n t h e m i n e r a l s o i l . Frequency, and mean s i g n i f i c a n c e , d e c l i n e d over t h e s t u d y p e r i o d : dead (brown, d e s i c c a t e d ) s h o o t s were o b s e r v e d i n 1985 (Malaspina) and 1986 (both s i t e s ) . T h i s s p e c i e s d i d not in v a d e p l o t s i n which i t was not p r e v i o u s l y r e c o r d e d . P t e r i d i u m a q u i l i n u m s u f f e r e d a g r e a t e r i n i t i a l s e t b a c k i n fr e q u e n c y t h a n d i d G. s h a l l o n . The f l u c t u a t i o n s i n f r e q u e n c y and mean s i g n i f i c a n c e o b s e r v e d a t b o t h s i t e s were p r o b a b l y due t o t h e e x t e n s i o n o f a c t i v e l y g r owing rhizomes i n t o new p l o t s ( i n v a s i o n ) , and a l a c k of l e a f buds on o l d e r p o r t i o n s o f rhi z o m e s . 167 Table 5.5 Number o f s c a r i f i e d p l o t s w i t h v e g e t a t i v e l y p e r s i s t i n g o r i n v a d i n g s h o o t s (as d e t e r m i n e d by s i z e and v i g o r o f g r o w t h ) . P l a n t s which s u r v i v e d from a s e e d l i n g ( i n d i c a t e d by "S" i n t h e y e a r t h e s e e d l i n g was observed) are a l s o i n d i c a t e d . Cheekye Loop M a l a s p i n a Year 1984 1985 1986 1984 1985 1986 S p e c i e s (n) (29) (29) (29) (28) (25) (25) A c e r macrophyllum 1 A n a p h a l i s m a r g a r i t a c e a 4 + 1S 2 2 IS 1 Apocynum a n d r o s a e m i f o l i u m 2 2 2 B e t u l a p a p y r i f e r a 2 Carex spp. 1 C i r s i u m v u l g a r e IS 1 1 E p i l o b i u m a n g u s t i f o l i u m 3 1 1 0 Equisetum p r a t e n s e 1 1 1 F r a g a r i a v i r g i n i a n a 1 1 2 1 G a u l t h e r i a s h a l l o n 19 19 17 17 13 12 H o l o d i s c u s d i s c o l o r 2 1 1 L i n n a e a b o r e a l i s 1 1 1 Mahonia n e r v o s a 2 2 2 1 + 1S 2 + 1S 3 P a x i s t i m a m y r s i n i t e s ' 2 2 2 Prunus e m a r g i n a t a 1 1 1 1 1 P t e r i d i u m a q u i l i n u m 18 17 17 14 13 12 Rubus l e u c o d e r m i s 1 1 1 R. p a r v i f l o r u s 1 2 2 1 R. u r s i n u s 8 11 14 5 6 13 Rosa gymnocarpa 1 1 1 S a l i x b e b b i a n a 1 S p i r a e a d o u g l a s i i 1 1 T r i e n t a l i s l a t i f o l i a 4 3 4 5 1 4 V a c c i n i u m p a r v i f o l i u m 1 1 1 Number o f s p e c i e s 17 15 15 11 10 14 168 Original 1984 198S 1986 Gaultheria shal lon 03 Original • Recovery • Invasion Significance Pteridium aqui l inum Original 1984 1985 1986 Rubus ursinus Original 1984 1985 1986 Original 1984 1985 1986 F i g u r e 5 . 3 Response of r e s p r o u t i n g s p e c i e s t o p l o t s c a r i f i c a t i o n . " S i g n i f i c a n c e " i s d e f i n e d i n Chapter 2 . 169 Frequency o f Rubus u r s i n u s d e c l i n e d most s t r o n g l y o f t h e t h r e e s p e c i e s , but t h i s s p e c i e s became r e - e s t a b l i s h e d a t f r e q u e n c i e s near, and mean s i g n i f i c a n c e s e x c e e d i n g , t h e o r i g i n a l l e v e l s over t h e c o u r s e o f t h e s t u d y . Recovery i n p r e v i o u s l y o c c u p i e d p l o t s ( r e s p r o u t i n g from t h e r o o t crown) as w e l l as i n v a s i o n o f new p l o t s (by t r a i l i n g , not r o o t e d , shoots) were i m p o r t a n t f o r t h i s s p e c i e s . 5.3.4.2 I n v a s i o n from seed The f r e q u e n c y o f o c c u r r e n c e o f s e e d l i n g s i n t h e s c a r i f i e d p l o t s was used t o d e s c r i b e changes over t h e c o u r s e o f t h e s t u d y . The c o v e r o f s e e d l i n g s was m i n i m a l , and f r e q u e n c y was c o n s i d e r e d t o be more r e l e v a n t . The number o f s e e d l i n g s p e r p l o t was not a s s e s s e d . Those s p e c i e s which o c c u r r e d i n t h e s c a r i f i e d p l o t s as s e e d l i n g s a r e l i s t e d i n Table 5.6. Of t h e s e s p e c i e s , o n l y i m p o r t a n t e a r l y s u c c e s s i o n a l s p e c i e s (Alnus r u b r a , A n a p h a l i s  m a r q a r i t a c e a , Rubus spp., and Sene c i o s y l v a t i c u s ) are d i s c u s s e d i n d e t a i l . Because of d i f f e r e n c e s i n greenhouse and f i e l d g e r m i n a t i o n r a t e s o f many s p e c i e s o b s e r v e d d u r i n g t h e assessment of seed d e n s i t i e s i n t h e seed bank (Chapter 3 ) , f r e q u e n c y o f o c c u r r e n c e , and not seed d e n s i t y , w i l l be emphasized. The y e a r l y p a t t e r n o f s e e d l i n g f r e q u e n c y i s compared w i t h t h e fr e q u e n c y o f t h e s p e c i e s i n t h e seed bank and seed r a i n ( F i g u r e 5.4) . In 1984, t h e g e r m i n a t i o n f r e q u e n c y o f A l n u s r u b r a was v e r y low, but e q u a l t o t h e f r e q u e n c y of i t s seed i n t h e seed bank. No seeds g e r m i n a t e d i n 1985: a l t e r n a t i v e l y , germinants d i d not 170 s u r v i v e t o t h e August assessment. In 198 6, s u r v i v i n g g e r m i n a n t s o c c u r r e d l e s s f r e q u e n t l y t h a n d i d seeds i n t h e t r a p s . S e e d l i n g s d i d not s u r v i v e u n t i l t h e next s c a r i f i e d p l o t assessment a t e i t h e r s i t e i n any o f t h e y e a r s o f s t u d y . A n a p h a l i s m a r q a r i t a c e a s e e d l i n g s were found each y e a r , a t f r e q u e n c i e s l e s s t h a n (1984 and 1985, a t b o t h s i t e s ) , t h e same as (1986 a t M a l a s p i n a ) , or g r e a t e r t h a n (1986 a t t h e Cheekye Loop) t h e f r e q u e n c i e s r e c o r d e d i n t h e seed bank and seed r a i n . Apparent o v e r - w i n t e r s e e d l i n g s u r v i v a l o c c u r r e d a t b o t h t h e Cheekye Loop (1984-85) and M a l a s p i n a (1985-86). Rubus spp. s e e d l i n g s were a l s o found e v e r y y e a r . There was no c o n s i s t e n t c o r r e l a t i o n between s e e d l i n g f r e q u e n c y and t h e f r e q u e n c y o f o c c u r r e n c e o f seeds i n t h e seed bank o r seed r a i n . A g a i n , s e e d l i n g s a p p a r e n t l y d i d not s u r v i v e t h e w i n t e r a t e i t h e r s i t e d u r i n g t h e s t u d y . S e e d l i n g s o f t h e a n n u a l S e n e c i o s y l v a t i c u s were c o n s i s t e n t l y s c a r c e r t h a n might be e x p e c t e d . W h i l e t h e r e was an average o f 800 g e r m i n a b l e seeds p e r square meter i n t h e seed banks of 80-90% of t h e p l o t s , s e e d l i n g s were v e r y r a r e . In Table 5.7, t h e o c c u r r e n c e of s e e d l i n g s i s compared w i t h t h a t o f w i t h seeds i n o r d e r t o f u r t h e r c l a r i f y r e g e n e r a t i o n " s t r a t e g i e s " . F o r A l n u s r u b r a , s e e d l i n g o c c u r r e n c e was a s s o c i a t e d w i t h t h e seed r a i n . I t was not c l e a r whether t h e seed s o u r c e f o r A n a p h a l i s m a r q a r i t a c e a and Rubus spp. was t h e seed bank o r seed r a i n . S e n e c i o s y l v a t i c u s s e e d l i n g s o c c u r r e d o n l y i n t h o s e p l o t s where seeds were p r e s e n t i n t h e seed bank. 171 T a b l e 5.6 Number o f s c a r i f i e d p l o t s w i t h s e e d l i n g s (as de t e r m i n e d by s i z e and/or t h e pr e s e n c e o f c o t y l e d o n s ) at t h e two st u d y s i t e s . Cheekye Loop M a l a s p i n a Year 1 984 1985 1986 1984 1985 1986 (n) ( 29) (29) (29) (28) (25) (25) A i r a p r a t e n s i s 1 A l n u s r u b r a 1 3 1 9 A n a p h a l i s m a r q a r i t a c e a 6 2 14 2 3 7 B e t u l a p a p v r i f e r a 1 3 C i r s i u m v u l q a r e 1 3 1 1 C o l l o m i a h e t e r o p h y l l a 3 Dan t h o n i a s p i c a t a 3 E p i l o b i u m a n q u s t i f o l i u m 5 1 2 E p i l o b i u m minimum 2 4 2 2 8 E p i l o b i u m w a t s o n i i 2 G a u l t h e r i a s h a l l o n 2 1 Gnaphalium spp. 1 H i e r a c i u m a l b i f l o r u m 1 2 5 1 1 H o l o d i s c u s d i s c o l o r 1 1 H y p o c h o e r i s r a d i c a t a 2 L u z u l a spp. 5 Mahonia n e r v o s a * 2 1 M y c e l i s m u r a l i s 5 2 6 3 2 Prunus e m a r q i n a t a 1 2 Pseudotsuqa m e n z i e s i i 1 2 Rubus spp. 6 2 7 5 3 7 Rumex spp. 1 S a l i x b e b b i a n a 1 S e n e c i o s y l v a t i c u s 3 1 7 6 Sonchus o l e r a c e u s 2 1 1 S p i r a e a d o u q l a s i i 1 3 2 2 Thu i a p l i c a t a 1 2 2 Tsuqa h e t e r o p h y l l a 1 3 2 V a c c i n i u m p a r v i f o l i u m 1 V i o l a spp. 1 2 3 Number o f s p e c i e s 15 5 17 18 8 17 * The o r i g i n o f t h i s spec i e s c o u l d not be c l e a r l y : i d e n t i f i e d as s e e d l i n g s o r v e g e t a t i v e r e c o v e r y . Cheekye Loop 1984 1985 A l n u s r u b r a 1986 100 80 g 60 <D 3 40 cr 2 20 Malaspina 1984 1985 1986 • Seed Bank • Seedlings • Seed Rain 100 80 >~ u c 60 a> 3 40 CT a> 20 U_ 0 Cheekye Loop 1984 m — 1985 1986 A n n p h n l i s m a r g a r i t a c e a Malaspina 1984 1985 1986 Figure 5.4 Frequencies of seedlings in s c a r i f i e d plots, and seeds in the seed bank and seed r a i n . F i g u r e 5 . 4 100 80 g 60 a 3 40 <x a> Cheekye Loop Rubus spp. 1984 1985 1986 100 80 >« o c 60 (D 3 40 tr a> i_ 20 u. 0 Malaspina 1984 1985 1986 Cheekye Loop sylvaticus 1984 1985 1986 100 80 g 60 <D 3 40 cr £ 20 Malaspina 1984 1985 1986 174 Table 5.7 T o t a l number o f s c a r i f i e d p l o t s i n which g e r m i n a n t s were observed, and t h e number of p l o t s i n which seeds o f t h e s e s p e c i e s were a l s o found i n t h e seed bank o r seed r a i n . "Unknown" r e f e r s t o t h o s e p l o t s i n which germinants o c c u r r e d but no seeds were r e c o r d e d i n t h e seed bank o r t h e seed r a i n . The t o t a l i s l e s s t h a n t h e sum o f t h e o t h e r t h r e e c a t e g o r i e s i f more th a n one seed s o u r c e was p o s s i b l e . S p e c i e s T o t a l Seed bank Seed r a i n Unknown A l n u s r u b r a Cheekye Loop 4 M a l a s p i n a 10 A n a p h a l i s m a r q a r i t a c e a Cheekye Loop 22 M a l a s p i n a 12 Rubus spp. Cheekye Loop 15 M a l a s p i n a 15 Sene c i o s y l v a t i c u s Cheekye Loop 4 M a l a s p i n a 13 0 3 1 0 8 2 12 7 9 1 5 6 1 2 12 0 7 9 4 0 0 13 0 0 175 5.4 D i s c u s s i o n V e g e t a t i v e r e s p r o u t i n g (from t h e bud. bank) was an i m p o r t a n t mechanism f o r r e - e s t a b l i s h m e n t by s a l a l ^ G a u l t h e r i a s h a l l o n ) . A l t h o u g h v i a b l e seeds o f s a l a l were p r e s e n t i n t h e seed bank (o n l y l o c a l l y a t M a l a s p i n a ) , t h i s appears t o have been an un i m p o r t a n t mode of r e g e n e r a t i o n . Because t h e seeds of s a l a l a re found p r e d o m i n a n t l y i n t h e f o r e s t f l o o r , and t h e f o r e s t f l o o r was removed d u r i n g s c a r i f i c a t i o n o f t h e stu d y p l o t s , t h i s o b s e r v a t i o n i s not unexpected. S e e d l i n g s o f s a l a l were not ob s e r v e d by S a b h a s r i (1961) under t y p i c a l f o r e s t c o n d i t i o n s i n Washington. S a l a l i s v a r i o u s l y c a l l e d a " r e s i d u a l " ( r e s p r o u t i n g from undamaged, p r e v i o u s l y dormant buds; Dyrness 1973, H a l p e r n 1987), a " s u r v i v o r " ( S t i c k n e y 1986), or a " r e s p r o u t e r " (Morgan and Neuenschwander 1988) . S i m i l a r l y , both b r a c k e n f e r n ( P t e r i d i u m a q u i l i n u m ) , and t r a i l i n g b l a c k b e r r y (Rubus u r s i n u s ) r e s p r o u t e d v i g o r o u s l y . B r acken f e r n i s c o n s i d e r e d t o be an " i n v a d e r " (Halpern 1987), a " s u r v i v o r " ( S t i c k n e y 1986), and an "endurer" (Rowe 1983). T r a i l i n g b l a c k b e r r y has been c a l l e d a " r e s i d u a l " (Dyrness 1973, H a l p e r n 1987), an " o p p o r t u n i s t " employing b o t h v e g e t a t i v e and seed s t r a t e g i e s (Morgan and Neuenschwander 1988), o r a " r e s i d u a l c o l o n i z e r " (from t h e seed bank) o r " s u r v i v o r " ( S t i c k n e y 1986). The o b s e r v e d d e c l i n e i n t h e f r e q u e n c y o f o c c u r r e n c e o f Rubus u r s i n u s was temporary, w h i l e t h a t e x p e r i e n c e d by P t e r i d i u m  a q u i l i n u m and G a u l t h e r i a s h a l l o n was s m a l l e r but more permanent (over t h e t h r e e y e a r s o f s t u d y ) . 176 Exposed, m o i s t m i n e r a l s o i l i s t h e p r e f e r r e d g e r m i n a t i o n s u b s t r a t e f o r r e d a l d e r (Alnus rubra) (e.g., W o r t h i n g t o n e t a l . 1962). S e e d l i n g s o f r e d a l d e r were e x t r e m e l y r a r e . The f a i l u r e o f s e e d l i n g e s t a b l i s h m e n t may r e f l e c t t h e d r y s i t e s s t u d i e d and/or th e below average J u l y and August r a i n f a l l i n 1984 and 1985 ( F i g u r e 5.5). Seed p r e d a t i o n c o u l d have a l s o c o n t r i b u t e d t o t h e r a r e n e s s o f s e e d l i n g s o f r e d a l d e r (and o t h e r s p e c i e s ) . Based on t h e o b s e r v a t i o n s i n t h i s s t u d y , t h e seed bank o f r e d a l d e r i s t r a n s i e n t , l a s t i n g u n t i l c o n d i t i o n s p r o m o t i n g g e r m i n a t i o n a r i s e ( i . e . , t h e f i r s t s p r i n g a f t e r d i s p e r s a l (Grime 1979; Thompson and Grime 1 9 7 9 ) ) . In o t h e r s t u d i e s , r e d a l d e r has been c a l l e d a " r e s i d u a l " (Halpern 1987) or an " o p p o r t u n i s t " (Morgan and Neuenschwander 1988) , r e f l e c t i n g i t s a b i l i t y t o r e s p r o u t up t o t h e age o f a p p r o x i m a t e l y 15 y e a r s ( H a r r i n g t o n 1984) and t h e wide d i s p e r s a l o f i t s seeds. A g a i n , low summer p r e c i p i t a t i o n may have c o n t r i b u t e d t o t h e low f r e q u e n c y o f s e e d l i n g s o f A n a p h a l i s m a r q a r i t a c e a and Rubus spp., e s p e c i a l l y i n 1985. W h i l e s e e d l i n g s were o b s e r v e d each y e a r , t h e i r o c c u r r e n c e c o u l d not be d e f i n i t i v e l y a s s o c i a t e d w i t h e i t h e r t h e seed bank or t h e seed r a i n : b o t h " s t r a t e g i e s " might be i m p o r t a n t f o r t h e s e s p e c i e s . A n a p h a l i s m a r q a r i t a c e a i s termed by o t h e r a u t h o r s as an " i n v a d e r " (Dyrness 1973, H a l p e r n 1987) or an " o f f - s i t e c o l o n i z e r " ( S t i c k n e y 1986). These names im p l y t h a t A. m a r q a r i t a c e a o r i g i n a t e s p r i m a r i l y from d i s p e r s e d , not s t o r e d , seed. A l t e r n a t i v e l y , t h e r e s u l t s i n Table 5.7 may s i m p l y h i g h l i g h t t h e d i f f i c u l t y o f c o r r e l a t i n g seed bank and seed r a i n 177 150T CO l _ CD 100-CD £ — 50-0-Cheekye Loop June July August Malaspina May June July August Figure 5.5 Monthly summer p r e c i p i t a t i o n at the two study s i t e s during the years i n which seedling establishment i n the s c a r i f i e d p l o t s was assessed. Data for the Cheekye Loop s i t e are from the Squamish weather station, those for the Malaspina s i t e are from the Sechelt weather s t a t i o n . 30-year means are from Environment Canada (1982) . 178 d a t a w i t h f i e l d o b s e r v a t i o n s o f s e e d l i n g e s t a b l i s h m e n t . P a t t e r n s o f seed d i s p e r s a l , and r e s u l t i n g s t o r a g e i n t h e s o i l , are e x t r e m e l y v a r i a b l e . The seed bank samples r e p r e s e n t e d o n l y l / 2 5 t h o f t h e s c a r i f i e d p l o t a r e a . I n f o r m a t i o n on seed l o n g e v i t y would h e l p t o a s s e s s t h e r o l e s o f seed bank and seed r a i n f o r A n a p h a l i s m a r q a r i t a c e a . F o r Rubus s p e c i e s , which have a p e r s i s t e n t seed bank, i n f o r m a t i o n r e g a r d i n g r e q u i r e m e n t s (and t r a n s l a t i o n o f t h e s e r e q u i r e m e n t s t o n a t u r a l c o n d i t i o n s ) f o r seed s c a r i f i c a t i o n and/or s t r a t i f i c a t i o n , endogenous dormancy mechanisms, and l o n g e v i t y , would be i n f o r m a t i v e . Germinable seeds of S e n e c i o s y l v a t i c u s were abundant i n t h e seed bank at b o t h s i t e s , but g e r m i n a n t s were r a r e . The d a t a i n T a b l e 5.7 i m p l y t h a t t h i s s p e c i e s does, or can, u t i l i z e a seed b a n k . " s t r a t e g y " . The r a r e n e s s o f s e e d l i n g s may r e f l e c t t h e apparent " p r e f e r e n c e " o f ragwort f o r r e c e n t l y burned s i t e s (West and C h i l c o t e 1968): s c a r i f i c a t i o n p r o b a b l y d i d not r e s u l t i n t h e r e l e a s e o f n u t r i e n t s t h a t t h i s s p e c i e s a p p a r e n t l y r e q u i r e s f o r g e r m i n a t i o n . That o t h e r s p e c i e s i n t h e genus Sen e c i o have a seed bank " s t r a t e g y " i s i m p l i e d by t h e l o n g e v i t y of seeds of t h e genus: H a r r i n g t o n (1972) r e p o r t e d seed l o n g e v i t i e s r a n g i n g from 22-100 y e a r s f o r o t h e r s p e c i e s o f S e n e c i o . The " i n v a d e r " " s t r a t e g y " o f S.. s y l v a t i c u s (Dyrness 1973, H a l p e r n 1987) may be supplemented by a seed bank " s t r a t e g y " i f t h e seeds do i n d e e d s u r v i v e f o r a l o n g t i m e and/or are not d e s t r o y e d by t h e exposure t o heat t h a t a f i r e can impose. I f s c i e n t i s t s hope t o p r e d i c t s u c c e s s i o n , i t i s e s s e n t i a l t o know whether s p e c i e s i n v a d e a f t e r o r s u r v i v e a d i s t u r b a n c e , 179 how t h i s i s a c c o m p l i s h e d , and how s p e c i e s r esponses a re a f f e c t e d by t h e s c a l e , i n t e n s i t y , and f r e q u e n c y o f d i s t u r b a n c e . T h i s knowledge w i l l a l s o be v a l u a b l e t o f o r e s t o r r i g h t - o f - w a y managers who hope t o a v o i d problems f o l l o w i n g h a r v e s t i n g o r r i g h t - o f - w a y c l e a r i n g . The work r e p o r t e d here had been d e s i g n e d t o d e t e r m i n e whether e a r l y s e r a i p l a n t community s p e c i e s c o m p o s i t i o n c o u l d be p r e d i c t e d g i v e n i n f o r m a t i o n on s p e c i e s p r e s e n c e and abundance i n the bud bank, seed bank, and seed r a i n . R e s p r o u t i n g o f v e g e t a t i v e l y p r o p a g a t i n g (bud bank) s p e c i e s was p r e d i c t a b l e . I n c o n t r a s t , s u c c e s s f u l r e g e n e r a t i o n from seed was not p r e d i c t a b l e due t o weather ( r a i n f a l l ) p a t t e r n s and t h e problems i n h e r e n t i n seed bank and seed r a i n s a m p l i n g (the non-random d i s t r i b u t i o n s of seeds s t o r e d i n t h e s o i l and o f seed d i s p e r s a l r e q u i r e i n t e n s i v e s a m p l i n g t o a t t a i n s t a t i s t i c a l r e l i a b i l i t y ) . F u r t h e r work on t h e p r e d i c t i o n o f p l a n t s u c c e s s i o n i s wa r r a n t e d . N e i t h e r t h e s c a l e o f t h e d i s t u r b a n c e imposed by t h e s c a r i f i c a t i o n o f 1 m.2 p l o t s , nor t h e f a c t t h a t t h e s i t e s had been c l e a r e d and seeded t o g r a s s e s ( i . e . , d i s t u r b e d ) a p p r o x i m a t e l y t h r e e y e a r s b e f o r e t h e i n i t i a t i o n o f t h e s t u d y , make t h e c o n d i t i o n s which c h a r a c t e r i z e t h i s s t u d y comparable t o many o f th o s e found i n f o r e s t e d s i t e s c l e a r e d f o r e i t h e r t r e e h a r v e s t o r r i g h t - o f - w a y c o n s t r u c t i o n . The system s t u d i e d here was complex ( i . e . , many p l a n t s p e c i e s ) , and t h e ti m e span o f i n t e r e s t (3 years) was s h o r t . There are many approaches t o , and o b j e c t i v e s f o r , f o r e s t s u c c e s s i o n m o d e l i n g (see, f o r example, Shugart and West 1980) . The o b j e c t i v e o f r e s e a r c h may be t o 180 p r e d i c t t h e abundance o f a p a r t i c u l a r s p e c i e s o r s p e c i e s group w i t h i n a l a r g e ( g r e a t e r t h a n 1 m2) a r e a , o r t o p r e d i c t l o n g e r -term s u c c e s s i o n a l p a t t e r n s (e.g., Noble and S l a t y e r 1977/ S t e e l e 1984; S t e i n h o r s t e t a l . 1985). I f so, c o n c l u s i o n s d i f f e r e n t from t h o s e p r e s e n t e d here are l i k e l y t o be reached. 5.5 C o n c l u s i o n s V e g e t a t i v e (bud bank) " s t r a t e g i e s " - r e s p r o u t i n g from r o o t c r o w n s , r h i z o m e s , and stumps, o r s u c k e r i n g - are w e l l u n d e r s t o o d and whether a s p e c i e s employs v e g e t a t i v e methods o f p e r s i s t e n c e i s g e n e r a l l y known. Seed s t r a t e g i e s o f f o r e s t s p e c i e s a re not as w e l l documented, and a r e g e n e r a l l y assumed. I n f o r m a t i o n r e g a r d i n g t h e seasons o f d i s p e r s a l and g e r m i n a t i o n , seed l o n g e v i t y , t h e depth p r o f i l e o f seed s t o r a g e , and t h e impacts o f s o i l d i s t u r b a n c e and weather on g e r m i n a t i o n and s e e d l i n g e s t a b l i s h m e n t would h e l p b o t h s c i e n t i s t s and managers i n t h e p r e d i c t i o n o f s u c c e s s i o n and i n t h e development o f a p r e v e n t i v e v e g e t a t i o n management " s t r a t e g y " t o modify t h e c o r r e c t i v e " s t r a t e g y " t h a t i s c u r r e n t l y employed. The work r e p o r t e d here s u g g e s t s t h a t on r o c k y s i t e s where f o r e s t f l o o r s a re s h a l l o w and rhizomes p e n e t r a t e t h e m i n e r a l s o i l , s c a r i f i c a t i o n which removes t h e f o r e s t f l o o r may o n l y t e m p o r a r i l y (and i n s i g n i f i c a n t l y ) reduce t h e p o p u l a t i o n o f some s p e c i e s ( G a u l t h e r i a s h a l l o n , P t e r i d i u m a q u i l i n u m ) because t h e rhizomes (bud banks) o f t h e s e s p e c i e s have been d i s t u r b e d . At th e same t i m e , g i v e n adequate r a i n f a l l which enhances s e e d l i n g s u r v i v a l , s c a r i f i c a t i o n may r e s u l t i n an i n c r e a s e i n t h e 181 e s t a b l i s h m e n t o f o t h e r s p e c i e s (Alnus r u b r a , Rubus spp.) by p r e p a r i n g an i d e a l seed bed or by e x p o s i n g t h e seed bank t o t h e e n v i r o n m e n t a l cues r e q u i r e d t o promote g e r m i n a t i o n . The management i m p l i c a t i o n s o f t h i s work are c l e a r . On s i t e s where t r a n s m i s s i o n l i n e r i g h t s - o f - w a y are p l a n n e d , t h e f o r e s t f l o o r s h o u l d not be removed where s e e d i n g i n by r e d a l d e r (or o t h e r s p e c i e s ) i s a c o n c e r n . The admonishments o f E g l e r and Foote (1975), not t o c l e a r cut f o r e s t s o r s c a r i f y t h e s o i l d u r i n g t h e i n i t i a l e s t a b l i s h m e n t of r i g h t s - o f - w a y i s v a l i d not o n l y f o r t h e e a s t e r n U.S., but a l s o f o r B r i t i s h Columbia. I n t h e c o n t e x t o f f o r e s t r e g e n e r a t i o n , where n e i t h e r s a l a l n or r e d a l d e r i s d e s i r e d , t h e s i t u a t i o n i s more d i f f i c u l t : s i t e t r e a t m e n t d e c i s i o n s must be based on t h e p a r t i c u l a r b r u s h h a z a r d s of each s i t e . Throughout t h i s s t u d y , seeds of c o n i f e r s were not abundant i n e i t h e r t h e seed bank o r t h e seed r a i n , and s e e d l i n g s were e x t r e m e l y r a r e . W h i l e good seed y e a r s do o c c u r p e r i o d i c a l l y f o r t h e s e s p e c i e s , i t would appear t h a t r e l i a n c e on n a t u r a l r e g e n e r a t i o n f o r f o r e s t e s t a b l i s h m e n t i n t h e D r i e r M a r i t i m e V a r i a n t o f t h e C o a s t a l Western Hemlock zone (CWHa2) and t h e Wetter M a r i t i m e C o a s t a l D o u g l a s - f i r subzone (CDFb) s h o u l d be d i s c o u r a g e d . L i t e r a t u r e C i t e d 182 A l a b a c k , P.B. (1984). P l a n t s u c c e s s i o n f o l l o w i n g l o g g i n g i n t h e S i t k a Spruce - Western 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 : i m p l i c a t i o n s f o r management. USDA F o r . Serv. P a c i f i c Northwest F o r e s t and Range Experiment S t a t i o n G e n e r a l T e c h n i c a l Report PNW-173. A l l s b r o o k s , D.W., D.K. Fo w l e r , and L . J . F o w l e r (1984). E v a l u a t i o n of woody v e g e t a t i o n on new t r a n s m i s s i o n l i n e r i g h t s - o f - w a y . I n : P r o c e e d i n g s o f t h e T h i r d I n t e r n a t i o n a l Symposium on E n v i r o n m e n t a l Concerns i n R i g h t - o f - w a y Management. A.F. C r a b t r e e (ed). M i s s i s s i p p i S t a t e U n i v e r s i t y , pp. 330-341. A r c h i b o l d , O.W. (1979) . B u r i e d v i a b l e p r o p a g u l e s as a f a c t o r i n p o s t f i r e r e g e n e r a t i o n i n n o r t h e r n Saskatchewan. Canadian J o u r n a l o f Botany 57: 54-58. A r c h i b o l d , O.W. (1980) . Seed i n p u t i n t o a p o s t f i r e f o r e s t s i t e i n n o r t h e r n Saskatchewan. Canadian J o u r n a l o f F o r e s t R e s e a r c h 10: 129-134. Arno, S.F. 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The r e l a t i o n s h i p o f b u r i e d , g e r m i n a t i n g seeds t o v e g e t a t i o n i n an o l d - g r o w t h C o l o r a d o s u b a l p i n e f o r e s t . Canadian J o u r n a l of Botany 56: 1505-1509. W i l k i n s o n , L. (1986). SYSTAT: The System f o r S t a t i s t i c s . SYSTAT, In c . , E v a n s t o n, I l l i n o i s . W i l l i a m s , B.K. (1983). Some o b s e r v a t i o n s on t h e use of d i s c r i m i n a n t a n a l y s i s i n e c o l o g y . E c o l o g y 64: 1283-1291. W i l l i a m s o n , R.L. (1983). S e e d f a l l under c o a s t a l D o u g l a s - f i r s h e l t e r w o o d s t a n d s . Northwest S c i e n c e 57: 205-211. Wool l e y , J.T., and E.W. S t o l l e r (1978). L i g h t p e n e t r a t i o n and l i g h t - i n d u c e d seed g e r m i n a t i o n i n s o i l . P l a n t P h y s i o l o g y 61: 597-600 . W o r t h i n g t o n , N.P., R.H. Ruth, and E.E. Matson (1962). Red a l d e r ; i t s management and u t i l i z a t i o n . U. S. Department of A g r i c u l t u r e M i s c e l l a n e o u s P u b l i c a t i o n 881: 44 pp. Zar, J.H. (1984). B i o s t a t i s t i c a l A n a l y s i s , 2nd e d i t i o n . P r e n t i c e -H a l l I n c . , Englewood C l i f f s , NJ. 718 pp. 193 Appendix - L i s t o f p l a n t s p e c i e s Nomenclature o f v a s c u l a r p l a n t s (angiosperms, c o n i f e r s , f e r n s and f e r n a l l i e s ) f o l l o w s t h a t o f H i t c h c o c k and C r o n q u i s t (1973). I r e l a n d e t a l . (1980) was f o l l o w e d f o r mosses. V a s c u l a r p l a n t s : Angiosperms: A c e r c i r c i n a t u m  A c e r macrophvllum  A q r o s t i s s c a b r a  A q r o s t i s s t o l o n i f e r a  A i r a p raecox  A l n u s r u b r a  A l n u s s i n u a t a  A m e l a n c h i e r a l n i f o l i a  A n a p h a l i s m a r q a r i t a c e a  Apocvnum a n d r o s a e m i f o l i u m  A q u i l e g i a formosa  Aruncus d i o i c u s  B e t u l a p a p y r i f e r a  C a p s e l l a b u r s a - p a s t o r i s  Carex a q u a t i l i s  Carex a r c t a  Carex canescens  C h i m a p h i l a u m b e l l a t a  C i c u t a d o u q l a s i i  C i r c a e a a l p i n a  C i r s i u m v u l q a r e  C l a y t o n i a s i b i r i c a  C o l l o m i a h e t e r o p h y l l a  Conyza c a n a d e n s i s  Cornus c a n a d e n s i s  Cornus s e r i c e a  C o r v d a l i s s e m p e r v i r e n s  C r a t a e g u s d o u q l a s i i  D a c t v l i s g l o m e r a t a  D a n t h o n i a s p i c a t a  Deschampsia d a n t h o n i o d e s  D i c e n t r a formosa  Disporum h o o k e r i  E p i l o b i u m a n g u s t i f o l i u m  E p i l o b i u m minutum  E p i l o b i u m w a t s o n i i  F e s t u c a r u b r a  F r a g a r i a v i r g i n i a n a  G alium t r i f l o r u m  G a u l t h e r i a s h a l l o n  G l y c e r i a g r a n d i s  Goodyera o b l o n q i f o l i a  Heuchera m i c r a n t h a  H i e r a c i u m a l b i f l o r u m  H o l o d i s c u s d i s c o l o r  H y p o c h o e r i s r a d i c a t a  Juncus e n s i f o l i u s  Juncus t e n u i s  L i l i u m columbianum  L i n n a e a b o r e a l i s P u r s h P u r s h W i l l d . L. L. Bong. (Regel) Rydb. (Nutt.) N u t t . (L.) Benth. i n Benth. L. F i s c h . i n DC. (Walt.) F e r n . Marsh. (L.) Medic. Wahlenb. B o o t t L. (L.) B a r t o n (DC.) C o u l t . & Rose L. (Savi) Ten. L. Dougl. ex Hook (L.) Cronq. L. L. (L.) P e r s . L i n d l . L. (L.) Beauv. ex Roem. ( T r i n . ) Munro ex Benth. (Haw.) Walp. (Torr.) N i c h o l s o n L. L i n d l . ex Hook. Barbey L. Duchesne Michx. P u r s h Wats. Raf. Dougl. ex L i n d l . Hook. (Pursh) Maxim. L. W i k s t r . W i l l d . Hanson ex Baker L. 195 L o l i u m perenne  L u z u l a p a r v i f l o r a  Lycopus u n i f l o r u s  L y s i c h i t u m americanum  Mahonia n e r v o s a  Mimulus g u t t a t u s  M y c e l i s m u r a l i s  Oenanthe sarmentosa  Oplopanax h o r r i d u s  P a x i s t i m a m y r s i n i t e s  Phleum p r a t e n s e  Physocarpus c a p i t a t u s  P l a n t a g o major  Poa compressa  Poa p r a t e n s i s  P o p u l u s t r e m u l o i d e s  P opulus t r i c h o c a r p a  Prunus e m a r q i n a t a  Rhamnus p u r s h i a n u s  R i b e s bracteosum  R i b e s sanguineum  Rosa qymnocarpa  Rubus l e u c o d e r m i s  Rubus p a r v i f l o r u s  Rubus s p e c t a b i l i s  Rubus u r s i n u s  S a l i x b e b b i a n a  S a l i x l a s i a n d r a  S a l i x s c o u l e r i a n a  S a l i x s i t c h e n s i s  Sambucus racemosa  S c i r p u s m i c r o c a r p u s  S e n e c i o s y l v a t i c u s  S e n e c i o v u l g a r i s  S m i l a c i n a s t e l l a t a  Sonchus o l e r a c e u s  Sparganium emersum  S p e r g u l a r i a r u b r a  S p i r a e a d o u g l a s i i  S t e l l a r i a c r i s p a  Taraxacum o f f i c i n a l e  T i a r e l l a t r i f o l i a t a  T o r r e y o c h l o a p a u c i f l o r a  T r i e n t a l i s l a t i f o l i a  T r i f o l i u m hybridum  T r i f o l i u m repens  T r i s e t u m cernuum  Typha l a t i f o l i a  V a c c i n i u m p a r v i f o l i u m  V e r o n i c a americana L. (Ehrh.-) Desv. Michx H u l t . & S t . John (Pursh) N u t t . DC. (L.) Dumort. P r e s l ex DC. (Sm.) Miq. (Pursh) Raf. L. (Pursh) K t z e . L. L. L. Michx. T o r r . & Gray ex Hook. (Dougl. ex Hook.) Walp. DC. Dougl. ex Hook. P u r s h N u t t . i n T o r r . & Gray Dougl. ex T o r r . & Gray N u t t . P u r s h Cham. & S c h l e c h t . Sarg. Benth. B a r r a t t i n Hook. Sanson i n Bong. L. P r e s l L. L. (L.) Desf. L. Rehmann (L.) P r e s l Hook. (Cham.) S c h l e c h t . Weber i n Wiggers L. ( P r e s l ) Church Hook. L. L. T r i n . L. Sm. i n Rees (Raf.) Schwein. ex Benth 196 C o n i f e r s : A b i e s q r a n d i s  P i n u s c o n t o r t a  Pseudotsuga m e n z i e s i i  Thuia p l i c a t a  Tsuga h e t e r o p h y l l a F e r n s and f e r n a l l i e s : A t h y r i u m f i l i x - f e m i n a  Blechnum s p i c a n t  D r v o p t e r i s expansa  Equisetum p r a t e n s e  Gymnocarpium d r y o p t e r i s  P o l y s t i c h u m munitum  P t e r i d i u m a q u i l i n u m (Dougl. ex D. Don) L i n d l Dougl. ex Loud. (Mirb.) Franco Donn ex D. Don i n Lamb. (Raf.) S a r g . (L.) Roth (L.) Roth ( P r e s l ) F r a s e r - J e n k i n s L. (L.) Newm. ( K a u l f . ) P r e s l (L.) Kuhn i n Decken Mosses: A t r i c h u m s e l w y n i i  Dicranum s c o p a r i u m  Hylocomium spl e n d e n s  K i n d b e r g i a oregana  Plagiomnium i n s i g n e  P o l y t r i c h u m i u n i p e r i n u m  P o l y t r i c h u m p i l i f e r u m  P l e u r o z i u m s c h r e b e r i  R h acomitrium canescens  R h y t i d i a d e l p h u s t r i q u e t r u s A u s t . Hedw. (Hedw.) ( S u l l . ) ( M i t t . ) Hedw. Hedw. ( B r i d . ) (Hedw.) (Hedw.) B.S.G. Ochyra Kop. M i t t . B r i d . Warnst, 

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