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Forest vegetation of west-central Vancouver Island, British Columbia Gagnon, Daniel 1985

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FOREST VEGETATION OF WEST-CENTRAL VANCOUVER ISLAND, BRITISH COLUMBIA by DANIEL GAGNON B. Sc., University of Ottawa, 1976 M. Sc., Universite de Montreal, 1980 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES Department of Botany We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRlflUH COLUMBIA A p r i l 1985 © Daniel Gagnon, 1985 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of Botany  The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date 4 J u n e 1 9 8 5 DE - 6 (3/81) ABSTRACT The objective of t h i s study was to q u a n t i t a t i v e l y describe the structure, composition and e c o l o g i c a l r e l a t i o n s h i p s of old-growth forests of west-central Vancouver Island. Data were obtained by sampling 172 p l o t s , at elevations up to 1000 m, located within t h i r t e e n drainage areas. Hypothesized r e l a t i o n s h i p s between vegetation and environmental v a r i a t i o n were examined using gradient analysis and m u l t i v a r i a t e methods. Successive r e c i p r o c a l averaging ordination of the vegetation data led to the recognition of s i x vegetation groups (f l o o d p l a i n , subalpine, Pinus contorta, Pseudotsuga, Thuja, Abies) and twenty-three community types. Data from the tree, sapling, seedling, shrub, herb and bryophyte-l i c h e n s t r a t a were used. Vegetation groups are d i f f e r e n t i a t e d along macro-climatic and s o i l parent material gradients. The vegetation of the Pseudotsuga group, dominant inland, appears to respond to gradients of elevation and s o i l moisture. The Thuja group i s found only near the coast, and i t s vegetation varies along gradients of s o i l nutrients and elevation; s o i l moisture having l i t t l e e f f e c t . The vegetation patterns of the Abies group are correlated to elevation and s o i l moisture. Cano-n i c a l v a r i a t e s analyses revealed a close r e l a t i o n s h i p between vegeta-t i o n a l and environmental patterns within most vegetation groups. A p r e c i -p i t a t i o n - c o n t i n e n t a l i t y gradient was i d e n t i f i e d as the major determinant of modal vegetation v a r i a t i o n . Along t h i s gradient, alpha and beta d i v e r s i t y increased towards the d r i e r and more continental i n t e r i o r as predicted. Tree s i z e - c l a s s d i s t r i b u t i o n data i n d i c a t e that Pseudotsuga  menziesii i s a s e r a i species i n most community types. The dominance of Thuja p l i c a t a near the coast may be maintained because of i t s longevity i i i and, possibly, i t s wind damage resistance. Attention i s drawn to the ec o l o g i c a l mechanisms operating i n coa s t a l forests which have important implications for t h e i r successful management. i v TABLE OF CONTENTS ABSTRACT i i LIST OF TABLES i x LIST OF FIGURES x i i ACKNOWLEDGEMENTS x i v CHAPTER 1. INTRODUCTION 1 A. GENERAL INTRODUCTION 1 B. OBJECTIVES AND HYPOTHESES 3 1. Environmental gradients and vegetation patterns. . . . 3 2. Vegetation patterns vs. environmental patterns . . . . 7 3. Vegetation homogeneity 9 4. The climax r o l e of Thuja p l i c a t a i n coa s t a l f o r e s t s . . 9 C. GRADIENT ANALYSIS 10 CHAPTER 2. STUDY AREA 13 A. LOCATION, PHYSIOGRAPHY AND GEOLOGY 13 1. Location and physiography 13 2. Bedrock geology 15 3. S u r f i c i a l geology 16 B. SOILS 17 C. CLIMATE ' 21 D. VEGETATION 24 V CHAPTER 3. METHODS 27 A. DATA COLLECTION 27 1. L o c a t i o n o f p l o t s 27 2. V e g e t a t i o n s a m p l i n g 28 3. S o i l and e n v i r o n m e n t a l d a t a 30 4. Nomenclature 31 B. DATA ANALYSIS 32 1. G r a d i e n t a n a l y s i s and o r d i n a t i o n s 32 a) I n d i r e c t g r a d i e n t a n a l y s i s and o r d i n a t i o n s . . . . 32 b) S u c c e s s i v e o r d i n a t i o n s 37 c) D i r e c t g r a d i e n t a n a l y s i s 39 2. Type d e l i m i t a t i o n . . . . . 41 a) D e f i n i t i o n o f groups and t y p e s 41 b) V e g e t a t i o n d a t a summary t a b l e s 43 3. C a n o n i c a l a n a l y s e s o f community t y p e s and v e g e t a t i o n groups based on e n v i r o n m e n t a l d a t a 45 4. V e g e t a t i o n s t r a t a homogeneity w i t h i n t y p e s 47 5. Tree s i z e - c l a s s s t r u c t u r e of community t y p e s 48 6. Tree s e e d l i n g abundance on undecomposed wood and f o r e s t f l o o r s u b s t r a t a 49 CHAPTER 4. RESULTS 50 A. GRADIENT ANALYSIS OF VEGETATION 50 1. G e n e r a l v e g e t a t i o n p a t t e r n s 50 a) 172 p l o t s o r d i n a t i o n 50 b) 140 p l o t s o r d i n a t i o n 52 2. V e g e t a t i o n p a t t e r n s w i t h i n the P s e u d o t s u g a group . . . 54 v i 3. Vegetation patterns within the Thuj a group 57 4. Vegetation patterns within the Abies group 59 5. Vegetation and environmental patterns on a distance from the coast gradient 62 B. CANONICAL ANALYSES OF VEGETATION GROUPS AND COMMUNITY TYPES BASED ON ENVIRONMENTAL DATA 64 1. Vegetation groups 64 2. Pseudotsuga types 66 3. Thuja types 68 4. Abies types 69 5. A l l types and the subalpine group 71 C. DESCRIPTION OF COMMUNITY TYPES 73 1. Pinus contorta vegetation group 74 Dry Pinus-Pseudotsuga forests (DI) 74 Coastal dry Pinus forests (D2) 75 2. Pseudotsuga vegetation group 77 Dry Pseudotsuga forests (PI) 77 Pseudotsuga-Thuja-Acer forests (P2) 78 Pseudotsuga-Linnaea forests (P3) 80 Pseudotsuga-Berberis forests (P4) 82 Tsuga-Pseudotsuga-Polystichum forests (P5) . . . . 83 Montane Tsuga forests (P6) 85 Montane Tsuga-Gaultheria forests (P7) 86 3. Thuja vegetation group 88 Coastal dry Thuja forests (Tl) 88 Coastal Tsuga-Blechnum-Polystichum forests (T2) 89 v i i Coastal montane Thuja forests (T3) 90 Coastal Thuja forests (T4) 91 Coastal wet Thuja forests (T5) 93 4. Abies vegetation group 95 Montane Tsuga-Abies-Gaultheria forests ( A l ) . . . . 95 Montane Abies-Tsuga f o r e s t s (A2) 96 Montane Tsuga-Abies f o r e s t s (A3) 97 Montane Abies-Streptopus forests (A4) 99 Lowland Abies f o r e s t s (A5) 101 Tsuga-Gaultheria-Blechnum forests (A6) 102 Tsuga-Blechnum-Polystichum f o r e s t s (A7) 103 5. Floodplain vegetation group 106 Floodplain f o r e s t s (Fl) 106 Floodplain forests (Lysichitum variant) (F2) . . . 108 6. Subalpine vegetation group (SA) 109 D. VEGETATION STRATA HOMOGENEITY AND SPECIES RICHNESS WITHIN TYPES I l l E. TREE SIZE-CLASS STRUCTURE OF COMMUNITY TYPES 114 1. Pseudotsuga types 115 2. Thuja types 117 3. Abies types 118 F. TREE SEEDLING ABUNDANCE ON UNDECOMPOSED WOOD AND FOREST FLOOR SUBSTRATA 119 v i i i CHAPTER 5. DISCUSSION 120 A. VEGETATION ANALYSIS 120 1. General vegetation patterns 120 2. The Pseudotsuga group 126 3. The Thuja group 130 4. The Abies group 134 5. Vegetation c l a s s i f i c a t i o n 138 6. The c l i m a t i c master gradient 142 7. Homogeneity and species richness 154 B. COMMUNITY DYNAMICS 158 1. Pseudotsuga community types 159 2. Thuja community types 164 3. Abies community types 171 4. Floodplain community types 174 CHAPTER 6. CONCLUSIONS 176 REFERENCES 180 APPENDIX 1. L i s t and constancy of species found i n vegetation p l o t s 251 APPENDIX 2. Environmental data d e s c r i p t i v e s t a t i s t i c s for vegetation groups and community types 267 APPENDIX 3. Community types complete understory vegetation tables 297 APPENDIX 4. Discriminant analysis r e s u l t s 334 i x LIST OF TABLES Table 1. L i s t of environmental v a r i a b l e s 191 2. L i s t of community c h a r a c t e r i s t i c s 192 3. Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the 172 p l o t s . . . . 193 4. Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the 172 pl o t s 194 5. Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the 140 p l o t s . . . . 195 6. Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the 140 plot s 196 7. Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the Pseudotsuga group 197 8. Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the Pseudotsuga group 198 9. Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the Thuja group. . . 199 X Table 10. Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the Thuja group 200 11. Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and three of the r e c i p r o c a l averaging ordination of the Abies group. . . 201 12. Product moment co r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the Abies group 202 13. Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the 105 modal plo t s 203 14. Product moment co r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the 105 modal plo t s 204 15. Names of community types and vegetation groups 205 16. Canonical analysis r e s u l t s of vegetation groups based on environmental data 206 17. Canonical analysis r e s u l t s of Pseudotsuga group community types based on environmental data 206 18. Canonical analysis r e s u l t s of Thuja group community types based on environmental data 207 19. Canonical analysis r e s u l t s of Abies group community types based on environmental data 207 20. Canonical analysis r e s u l t s of a l l community types '. . based on environmental data 208 x i Table 21. Correlations between canonical v a r i a t e s and environmental v a r i a b l e s 209 22. Pseudotsuga group and community type Dl tree s t r a t a summary table 210 23. Pseudotsuga group and community type Dl understory s t r a t a summary table 212 24. Thuja group and community types D2, F l and F2 tree s t r a t a summary table 216 25. Thuja group and community types D2, F l and F2 understory s t r a t a summary table 218 26. Abies group tree s t r a t a summary table 223 27. Abies group understory s t r a t a summary table 225 28. Subalpine vegetation group tree s t r a t a summary table 228 29. C l a s s i f i c a t i o n of community type s o i l s to the subgroup l e v e l 229 30. Mean species richness of community types 230 31. Homogeneity and richness of vegetation s t r a t a within community types compared with a f i r e disturbance index 231 32. Tree seedling abundance on undecomposed wood and for e s t f l o o r substrata within community types 232 x i i LIST OF FIGURES F i g . 1. Study area and p l o t l o c a t i o n map 233 2. Climate diagrams 234 3. Watersheds sampled i n the study area 235 4. Microplot sampling designs 236 5. Reciprocal averaging ordination of forest vegetation data from 172 p l o t s 237 6. Reciprocal averaging ordination of forest vegetation data from 140 p l o t s 238 7. Reciprocal averaging ordination (a) and d i r e c t ordination (b) of 59 p l o t s from the Pseudotsuga vegetation group 239 8. Reciprocal averaging ordination (a) and d i r e c t ordination (b) of 40 p l o t s from the Thuja vegetation group 240 9. Reciprocal averaging ordination (a) and d i r e c t ordination (b) of 40 p l o t s from the Abies vegetation group 241 10. Reciprocal averaging ordination of 105 modal vegetation p l o t s 242 11. Relationships between species basal areas, LFH t h i c k n e s s / e f f e c t i v e rooting depth r a t i o s , and distance from the coast i n 105 modal vegetation p l o t s 243 x i i i F i g . 12. Isol i n e maps of vascular species richness, LFH th i c k n e s s / e f f e c t i v e rooting depth r a t i o , and' climate v a r i a b l e s within the study area 244 13. Canonical analyses of vegetation groups, and community types within three groups, based on environmental data 245 14. Canonical analyses of twenty-two community types and the subalpine group based on environmental data . . . . 246 15. Tree s i z e - c l a s s structure : Pseudotsuga group community types and dry Pinus-Pseudotsuga . forests (Dl) 247 16. Tree s i z e - c l a s s structure : Thuja group commu-n i t y types and coas t a l dry Pinus forests (D2) 248 17. Tree s i z e - c l a s s structure : Abies group commu-n i t y types and coas t a l Tsuga-Blechnum-Polystichum forests (T2) 249 18. Community type photographs 250 x i v ACKNOWLEDGEMENTS I would l i k e to express my h e a r t f e l t gratitude to my thesis super-v i s o r , Dr. G.E. B r a d f i e l d , whose support, help and advice were always forthcoming. This work was greatly improved through his c a r e f u l d i r e c t i o n . I wish to thank MacMillan Bloedel Limited, Woodlands Services, for t h e i r f i n a n c i a l and l o g i s t i c support. I hope that some of the r e s u l t s of t h i s study, when applied to forest management, w i l l eventually repay t h e i r investment. I am g r a t e f u l to Dr. E.C. Packee (University of Alaska, F a i r -banks) , formerly of MacMillan Bloedel Limited, for i n i t i a t i n g t h i s project. Drs. L.M. Lavkulich, J. Maze, E.C. Packee and W.B. Schofield, as members of my thesis committee, deserve many thanks for t h e i r guidance. I am much obliged to my colleague and f r i e n d , Mr. G.A. Spiers, who dug, described and sampled most of the s o i l p r o f i l e s during t h i s study. Thanks also to Mr. F.M. Palmer, our e v e r - e f f i c i e n t sampling a s s i s t a n t , and to Mrs. C. Kennedy and her technicians, from the MacMillan Bloedel Limited S o i l s Laboratory, who provided a l l the s o i l analyses. Thanks to Dr. W.B. Schofield, Mr. R.K. Scagel, Mr. T. Goward and Dr. W. Noble for t h e i r taxonomic assistance with d i f f i c u l t specimens; to Mr. D. Z i t t i n of. U.B.C. who wrote several useful computer programs for t h i s project; to Mrs. E. Lemaire who expertly typed the manuscript. I owe a s p e c i a l word of gratitude to my wife, P a t r i c i a A. Wood, for her continuing encouragement, patience and cheerfulness throughout my long career as a graduate student. I am thankful to the N.S.E.R.C. of Canada for a graduate scholar-ship . 1 CHAPTER 1 INTRODUCTION A. GENERAL INTRODUCTION Vancouver Island possesses the most productive forest stands i n Canada, with the largest t o t a l basal area, wood volume per hectare, and the t a l l e s t trees. Small protected areas containing examples of such stands can be found i n MacMillan P r o v i n c i a l Park, better known as "Cathedral Grove", and i n P a c i f i c Rim National Park. Elsewhere on Vancouver Island, "old-growth" stands have been disappearing s t e a d i l y through continued harvesting by the forest industry. Low-elevation, old-growth forests are almost non-existent i n c e r t a i n parts of Vancouver Island, e s p e c i a l l y on the east coast and i n the Port A l b e r n i area. E c o l o g i c a l studies of the few remaining stands of old-growth forests are urgently needed to provide valuable, or even v i t a l information for future management of Canada's west coast forests on a s c i e n t i f i c basis. The study of old-growth forests w i l l y i e l d information on how these forests maintain themselves, where they a t t a i n the best growth, and which s i t e and s o i l properties are important to t h e i r growth. Such information can a s s i s t i n developing guidelines for harvesting and post-harvesting treatments (slashburning, s c a r i f i c a t i o n , e t c . ) , as well as provide s i t e - s p e c i f i c l i s t s of tree species that are sui t a b l e for re-.' planting. The future success of forest management i s due, i n large part, to proper s e l e c t i o n of suitable species for replanting a f t e r logging. 2 This need has already been dramatically demonstrated by the numerous f a i l u r e s of Pseudotsuga menziesii plantation, ten to t h i r t y years a f t e r planting (Spiers et a l . , 1983; Carter et a l . , 1984). The loss of ten to t h i r t y years i n what i d e a l l y should be an eighty year r o t a t i o n period i s a p o t e n t i a l d i s a s t e r . Forest management on a sound e c o l o g i c a l basis aims at preventing such c o s t l y e r r o r s . If the study of old-growth forests can contribute valuable i n f o r -mation for forest management purposes, i t i s e s s e n t i a l that such studies be undertaken soon, while nearly a l l the v a r i a t i o n expressed i n old-growth forest vegetation, along various environmental gradients, can s t i l l be found. In response to these concerns, one of the major objectives of t h i s study i s to provide a d e t a i l e d e c o l o g i c a l study of old-growth forest communities on west-central Vancouver Island (Fig. 1). Numerous e c o l o g i c a l studies of forest communities i n coastal B r i t i s h Columbia have been c a r r i e d out by Dr. V.J. Krajina and h i s students. Most of these studies, however, were done on the east coast of Vancouver Island (Krajina and Spilsbury, 1953; Mueller-Dombois, 1959; M^Minn, 1960) or on the adjacent mainland ( O r l o c i , 1961, 1964; Brooke et a l , 1970; Klinka, 1976). The r e l a t i v e l y few e c o l o g i c a l studies of western Vancouver Island have been confined to small areas or s p e c i a l habitats (Wade, 1965; Kuramoto, 1965; Cordes, 1972; Kojima and Krajina, 1975). Other researchers also have studied the vegetation of the east coast of Vancouver Island (Beese, 1981; Roy, 1984; Roehmer, 1972). The vegetation of the Carnation Creek Experimental Watershed on western Vancouver Island was described by Oswald (1973, 1974, 1975). Also, two noteworthy 3 studies of western Vancouver Island forests above the community l e v e l are those of Packee (1976) and Klinka et al_. (1979). B. OBJECTIVES AND HYPOTHESES Although the des c r i p t i o n of the structure, composition and eco-l o g i c a l c h a r a c t e r i s t i c s of the old-growth forest communities of west-ce n t r a l Vancouver Island i s the major objective of t h i s study, several other objectives w i l l be considered concurrently. These secondary objectives may be stated i n the form of hypotheses, or predictions from the l i t e r a -ture. These working hypotheses are not devised to be examined through the formal hypotheses t e s t i n g procedure described as "strong inference" by P i a t t (1964). Quinn and Dunham (1983) have argued that, " s t r i c t a p p l i -cation of a formal strong inference methodology to e l u c i d a t i n g p o t e n t i a l causes of patterns i n nature i s frequently i n f e a s i b l e " . A great deal of t h i s d i f f i c u l t y resides i n the formulation of appropriate n u l l hypo-theses. Also, causal factors of e c o l o g i c a l patterns are probably not mutually exclusive, and i t becomes impossible to d i s t i n g u i s h between a l t e r n a t i v e hypotheses i f these causal factors operate simultaneously (Quinn and Dunham, 1983). Therefore, the hypotheses formulated below should instead serve as reference points f o r the i n t e r p r e t a t i o n and discussion of the r e s u l t s obtained. 1. ENVIRONMENTAL GRADIENTS AND VEGETATION PATTERNS Numerous studies have pointed out the major environmental gradients generally responsible for the largest amounts of v a r i a t i o n within vege-t a t i o n . Nevertheless, i t remains i n t e r e s t i n g to examine for the f i r s t 4 time vegetation-environment r e l a t i o n s h i p s i n a large, c l i m a t i c a l l y diverse area of western Vancouver Island. S p e c i f i c questions asked at the outset of the research were : Which environmental gradient, or gradients, w i l l be associated with the largest amount of v a r i a t i o n i n the vegetation over the whole study area? If c e r t a i n environmental factors are held constant (through manipulation of f i e l d data), do others emerge as having p o t e n t i a l l y s i g n i f i c a n t control over vegetation patterns? Are the predominant environmental gradients the same i n clima-t i c a l l y d i f f e r e n t parts of the study area? These questions can- be investigated through the use of a func-t i o n a l approach to plant community ecology. Austin e_t aj^. (1984) summarized t h i s approach and pointed out i t s s i m i l a r i t i e s to gradient analysis. The f u n c t i o n a l approach was pioneered i n the study of s o i l s by Jenny (1941), i n which s o i l s were expressed as being a function of climate, parent material, topography, a b i o t i c factor and time. Jenny (1941) suggested that i f a l l factors except one were held constant, r e l a t i o n s h i p s between t h i s one factor and s o i l properties could be demonstrated and analyzed (Austin et a l . , 1984). A s i m i l a r f u n c t i o n a l , f a c t o r i a l approach to plant ecology was l a t e r proposed by Major (1951) and Crocker (1952). S i m i l a r l y , i n h i s d i r e c t gradient analysis of the Great Smoky Mountains, Whittaker (1956) assumed that vegetation properties were related to meso-climate and topography, when parent material, the b i o t i c factor and time were held constant. The meso-climate gradient was estim-ated by elevation (approximating temperature), and the topography gradient 5 was measured by slope aspect and degree of exposure (approximating moisture, Whittaker (1956)). These two gradients served as the axes of the now c l a s s i c , two-dimensional diagrams of the vegetation of the mountainous, areas studied by Whittaker (Whittaker, 1956; 1960; Whittaker and Niering, 1965). A t h i r d f a c t o r , such as parent material or l a t i -tude (macro-climate) or successional status (time) can be introduced by producing elevation-topography diagrams for areas d i f f e r i n g only i n the t h i r d factor of i n t e r e s t (Whittaker, 1960; Whittaker and Niering, 1968b; Perring, 1960; Peet, 1978; Kessel 1979). Kessel (1979) produced a com-prehensive s e r i e s of two-dimensional diagrams to display major vegetation-environment r e l a t i o n s h i p s for G l a c i e r National Park., Montana. Such graphical methods have permitted the e c o l o g i c a l i n t e r p r e t a t i o n of complex d i s t r i b u t i o n patterns of i n d i v i d u a l species and community c h a r a c t e r i s t i c s , including species d i v e r s i t y and p r o d u c t i v i t y (Whittaker and Niering, 1975). Within t h i s study area the b i o t i c factor (herbivory, competition) i s assumed to be constant, as i s the time f a c t o r , since mostly old-growth forest stands were sampled. Climate, topography and parent material are the environmental factors showing the greatest v a r i a t i o n within the study area. It i s generally accepted that macro-climate (mainly temperature and p r e c i p i t a t i o n ) w i l l influence most strongly the vegetation of an area. Elevation represents a major p r e c i p i t a t i o n and temperature gra-dient within the present study area; as w e l l , p r e c i p i t a t i o n declines markedly along a west to east axis from coastal to more i n t e r i o r parts 6 of the i s l a n d . Macro-climate and meso-climate l e v e l s can be s u b j e c t i v e l y distinguished by scale. For example, there i s a macro-climatic d i f f e -rence between Tofino and Port A l b e r n i ( d i f f e r e n t t o t a l p r e c i p i t a t i o n ) , while there i s only a meso-climatic difference between the north and south facing slopes surrounding Sproat Lake. In h i s study of the vegetation of the Siskiyou Mountains of Oregon, Whittaker (1960) documented an increase i n alpha and beta diver-s i t y along a gradient from the coast to the i n t e r i o r . Alpha d i v e r s i t y represents the species richness, or number of species at a s i t e , while beta d i v e r s i t y r e f e r s to the rate of change i n species composition (termed "species turnover") along an environmental gradient (Whittaker, 1975). A s i m i l a r trend was detected i n the c e n t r a l Washington Cascade Mountains by Del Moral and Watson (1978), and i n Finland by Oksanen (1983). From the above, the following hypotheses were formulated for the study of the vegetation of west-central Vancouver Island using gradient analysis methods : a) Vegetation and i n d i v i d u a l species patterns w i l l be most strongly correlated with macro-climatic factors over the e n t i r e study area. b) Following macro-climate, parent material factors w i l l exert the next strongest influence on vegetation and species patterns. c) If macro-climate and parent material are held f a i r l y constant, that i s i f subsections of the e n t i r e study area are analysed 7 separately, meso-climate w i l l be most strongly correlated with vegetation and species patterns. d) Within the same subsections as in (c) topographical factors related to s o i l moisture will- follow meso-climate in their apparent control over vegetation and species patterns. e) The macro-climatic gradient of decreasing precipitation and increasing continentality, progressing inland from the coast, should be reflected by increases in both alpha and beta diver-sity in the vegetation. 2. VEGETATION^PATTERNS VS. ENVIRONMENTAL PATTERNS A major assumption of indirect gradient analysis, or indirect ordination, i s that the vegetation patterns illustrated reflect under-lying environmental patterns (Whittaker, 1967; 1978). A further objec-tive of this thesis is to examine the validity of this assumption within the present study area. The degree to which communities, differentiated by vegetation attributes, can also be independently delineated using environmental variables is a good indication of the relationships between vegetation and environmental patterns. Old-growth forests that have been deve-loping for centuries would seem to represent a system where vegetation and environment are in close harmony. Vegetation va r i a b i l i t y introduced by most small scale disturbances (eg. deaths of isolated individuals) is minimized in such forests. Disturbance on a larger scale (eg. f i r e or 8 storm damage) may have more profound e f f e c t s on vegetation patterns depending on the type, i n t e n s i t y , and frequency of the disturbance. Counteracting the deterministic r e l a t i o n between environment and vege-t a t i o n are stochastic events, such as the establishment of d i f f e r e n t species i n newly opened microsites, or the year to year v a r i a t i o n i n seed production by d i f f e r e n t species, which also are c h a r a c t e r i s t i c of the developing f o r e s t . Thus two i d e n t i c a l disturbances, but not occurring at the same time or place, may often promote the establishment of a d i f -ferent vegetation due to stochastic events. These ideas are reformulated i n the following statements or hypo-theses : a) The i n t e r p l a y of competitive forces between populations of species i n old-growth forests over long periods of time has resulted i n species assemblages best suited, or adapted, to the s p e c i f i c s i t e conditions found within each stand; therefore, the vegetation patterns should c l o s e l y match the environmental patterns. b) It follows from the preceding statement, that within parts of the study area where large scale natural disturbances ( i . e . f i r e ) are, or have been, more frequent, r e l a t i o n s h i p s between vegetation patterns and environmental patterns would be expected to be weaker. 9 3. VEGETATION HOMOGENEITY Another expected c h a r a c t e r i s t i c of old-growth forests i s homo-geneity of vegetation s t r a t a within communities under r e l a t i v e l y uniform environmental conditions. Again, a decrease i n vegetation homogeneity i s expected where large scale disturbances have played, or s t i l l play a r o l e . These ideas can be reformulated as follows : Where large scale natural disturbances ( i . e . f i r e ) are, or have been, more frequent, vegetation homogeneity w i l l be reduced; therefore, e c o l o g i c a l l y s i m i l a r s i t e s w i l l show a greater vegetation v a r i a b i l i t y within these parts of the study area. 4. THE CLIMAX ROLE OF THUJA PLICATA .IN COASTAL FORESTS Thuja p l i c a t a i s a major forest dominant of the Estevan Coastal P l a i n . This area, located on the extreme west coast of Vancouver Island, receives over 2000 mm of p r e c i p i t a t i o n annually (Fig. 2). Despite the dominant status of Thuja p l i c a t a i n t h i s area, there i s some doubt that i t i s the major climax species. Tsuga heterophylla and Abies amabilis both show abundant seedling regeneration and might be predicted to eventually replace Thuja p l i c a t a as dominant species. B e l i e f l e u r (1981) using a Markovian simulation model of succession (and an admittedly small data set) showed that succession should lead quickly to Tsuga heterophylla dominance. B e l i e f l e u r (1981) claimed, however, that the r e s u l t s were an a r t i f a c t of the data set and agreed with Packee (1976) that Thuja  p l i c a t a should maintain i t s dominance over time. Klinka e_t a l . (1979) 10 include Picea s i t c h e n s i s , Abies amabilis and Tsuga heterophylla as dominant trees of t h e i r zonal ecosystem (climax association on mesic s i t e s ) i n the coastal areas where Thuja p l i c a t a dominates. Nevertheless, they describe old-growth stands with very large Thuja p l i c a t a trees, which they consider to be nearly c l i m a t i c climax ecosystems, owing to the v i r t u a l absence of forest f i r e s . Since there i s a concensus that the largest amount of disturbance i n these stands comes from the wind-throw of i n d i v i d u a l trees (Klinka et a l . , 1979; personal observation), the following hypothesis w i l l be investigated : In the old-growth, Thuja p l i c a t a dominated forests of the west coast of Vancouver Island, Thuja p l i c a t a can be considered a "climax" species, capable of regenerating and maintaining i t s e l f i n d e f i n i t e l y . C. GRADIENT ANALYSIS Gradient analysis i s the major conceptual approach used to generate and analyse the r e s u l t s of t h i s study. The o r i g i n , basic assumptions and premises of t h i s approach are discussed here b r i e f l y . Gradient analysis i s a methodology of vegetation study o r i g i n a l l y developed by R.H. Whittaker i n h i s study of the vegetation of the Great Smoky Mountains (Whittaker, 1956). He l a t e r used the same approach i n his studies of the Siskiyou Mountains of Oregon (Whittaker, 1960) and the Santa Catalina Mountains of Arizona (Whittaker and Neiring, 1965; 1968a; 1968b; 1975). Gradient analysis i s based on the Gleasonian view of vegetation as a continuum (Gleason, 1926; Mcintosh, 1967), and has 11 been l a r g e l y responsible f o r the now general acceptance of t h i s view (whittaker, 1978). The approach consists of studying the v a r i a t i o n i n the structure and composition of vegetation along environmental gradients, using variables from three d i f f e r e n t l e v e l s : ;(.l) the a b i o t i c environment, (2) species populations, and (3) community c h a r a c t e r i s t i c s such as div e r -s i t y or p r o d u c t i v i t y (Whittaker, 1967). I n t e r r e l a t i o n s between these three l e v e l s of va r i a b l e s can be studied through the use of two-dimensional diagrams (Whittaker, 1956; 1960; 1965; 1967; 1978; Kessel, 1979). In t h i s p a r t i c u l a r approach, environmental gradients surmised to be important are represented as axes, and the sampled p l o t s are arranged, or ordinated, within the reference space. This technique i s now referred to as d i r e c t gradient a n a l y s i s , p a r t i c u l a r l y since the advent of the Wisconsin polar ordination method and other m u l t i v a r i a t e techniques based s o l e l y on vege-t a t i o n data (Whittaker and Gauch, 1978). Such ordinations are referred to as methods of i n d i r e c t gradient analysis (thus, i n d i r e c t o r d i n a t i o n s ) , since they represent diagrammatically patterns of v a r i a t i o n i n the vege-t a t i o n which may be interpreted i n terms of e c o l o g i c a l gradients. It i s assumed that the pattern of vegetation v a r i a t i o n r e f l e c t s underlying environmental gradients (Whittaker, 1967; 1978; Whittaker and Gauch, 1978); the strengths of such r e l a t i o n s h i p s can be c l a r i f i e d i n follow-up analyses by c o r r e l a t i n g environmental variables with the derived vege-ta t i o n gradients. Only recently has gradient analysis been used with a resource management purpose i n mind. Kessel (1979) applied gradient analysis techniques i n the development of a computerized forest f i r e management program f or Gl a c i e r National Park, Montana. This thesis uses gradient 12 analysis i n seeking to provide e c o l o g i c a l information necessary f o r forest management decisions and explores some of the t h e o r e t i c a l aspects on which t h i s approach i s based. 13 CHAPTER 2. STUDY AREA A. LOCATION, PHYSIOGRAPHY AND GEOLOGY 1. LOCATION AND PHYSIOGRAPHY The study area i s located on the west-central coast of Vancouver Island. The area extends approximately 110 km along the P a c i f i c Ocean coast, from the Cypre River north of Tofino (49°20'N, 126°W), to the N i t i n a t River east of Bamfield (48°45'N, 124°35'W). From the coast, the study area extends 60 km inland to Port A l b e r n i (Fig. 1). The study area l i e s e n t i r e l y within the Vancouver Island Moun-tains physiographic subdivision (Holland, 1964). This unit i s further subdivided into the Vancouver Island Ranges, the Estevan Coastal P l a i n , and the Alb e r n i Basin. The Vancouver Island Ranges are formed by several small mountain ranges generally following a northwest to southeast axis, separated and dissected by deep, U-shaped v a l l e y s (Holland, 1964). One of these v a l l e y s , flooded by the sea, i s the A l b e r n i I n l e t , a c l a s s i c a l f j o r d c e n t r a l l y located i n the study area and opening to the P a c i f i c Ocean through the Barkley Sound. Numerous v a l l e y s contain large, f j o r d - l i k e lakes such as Sproat Lake, Nahmint Lake, Henderson Lake, the two arms of Kennedy Lake, and Great Central Lake at the northern boundary of the study area (Fig. 1). N i t i n a t Lake, at the southeast l i m i t of the study area, has the p e c u l i a r i t y 14 of being linked d i r e c t l y to the Ocean at high tides. The highest peak within the study area i s Mt. K l i t s a at 1642 m. The Golden Hinde (2,200 ra), north of the study area, i s the highest mountain on Vancouver Island. Pre-Pleistocene u p l i f t and erosion produced a rugged topography which was extensively modified during the Pleistocene g l a c i a t i o n s (Hol-land, 1964). During the most recent g l a c i a t i o n the Vancouver Island i c e cap was joined with that of the mainland (Muller et a l . , 1974). There was a southwest flow of i c e across the Island when the general topography allowed i t , such as along the Al b e r n i I n l e t (Fyles, 1963). Recent botanical discoveries suggest that the i c e cover was not complete on Vancouver Island's Brooks Peninsula during the Pleistocene Fraser g l a c i a t i o n (Pojar, 1980). Endemic earthworms found on Vancouver Island would also support the existence of a g l a c i a l refugium (Spiers et a l . , 1984). The Estevan Coastal P l a i n i s a narrow band, 1.5 to 10 km wide, extending nearly 275 km along the west coast of Vancouver Island (Holland, 1964). This coastal p l a i n reaches i t s maximum width: within the study area between Tofino and Ucluelet (Fig. 1). The topography i s generally l e v e l to strongly r o l l i n g with scattered bedrock k n o l l s . Surface materials consist of thick, unconsolidated Pleistocene and Recent depo-s i t s . Drainage on these materials i s generally imperfect to very poor (Valentine, 1971). In the portion of P a c i f i c Rim National Park situated between Tofino and Ucluelet wave action on these deposits has created long and wide sand beaches. 15 The A l b e r n i Basin i s a low elevation area (below 300 m) with r e l a t i v e l y l e v e l r e l i e f at the head of the Albe r n i I n l e t (Holland, 1964). No plots were sampled i n t h i s physiographic section since i t i s mostly a g r i c u l t u r a l . There are numerous r i v e r s within the study area. The drainage basins of some of the largest r i v e r s (Kennedy, Taylor, N i t i n a t , S a r i t a , Klanawa, and Nahmint)were used to subdivide the study area for sampling purposes (Fig. 3). 2. BEDROCK GEOLOGY The bedrock geology of southwestern B r i t i s h Columbia including Vancouver Island i s complex. Several authors have described the hetero-geneous geology of the area (Muller, 1971; Muller and Carson, 1969; Muller .et al•> 1974) and a de t a i l e d summary i s provided by Packee (1976). Rocks'.of the Mesozo'ic era predominate. These are mainly fau l t e d and folded sedimentary and volcanic rocks, frequently intruded by igneous ba t h o l i t h s (Muller and Carson, 1969; Muller, 1971). Lime-stone, chert, a r g i l l i t e , t u f f , and greywacke are the most common types of sedimentary rock (Day et a l . , 1959; Muller and Carson, 1969). Three cycles of volcanism have been described f o r Vancouver Island (Northcote, 1973). Recent geol o g i c a l discoveries i n d i c a t e that Vancouver Island and the Wrangell Mountains, near the coastal Yukon-Alaska border, may have d r i f t e d north from south of the equator through plate tectonic a c t i v i t y (Jones et a l . , 1983). 16 3. SURFICIAL GEOLOGY The main factors i n f l u e n c i n g the s u r f i c i a l geology of the study area have been the l a s t Pleistocene g l a c i a t i o n , which ended approxi-mately 12,000 to 14,000 years ago according to pa l y n o l o g i c a l evidence (Hebda, 1983; Mathewes, 1973), and various p o s t - g l a c i a l events. The major types of s u r f i c i a l materials found on the west coast of Vancouver Island are g l a c i a l t i l l s , g l a c i o f l u v i a l deposits, and marine sediments. Because of the mountainous topography, c o l l u v i a l material i s frequently encountered (Jungen and Lewis, 1978). The colluvium i s formed on slopes from bedrock fragments and slumping morainal material. Marine and f l u v i o -g l a c i a l deposits, i n the form of sands and clays, are predominant on the Estevan Coastal P l a i n (Valentine, 1971; Jungen and Lewis, 1978). These deposits originated when the land, depressed by the ic e pack, was invaded by the sea following the g l a c i a l r e t r e a t ; rebounding of the land has now raised these sediments above sea l e v e l . Recent a l l u v i a l deposits are found along a l l major r i v e r s . 17 B. SOILS B r i t i s h Columbia has been divided into a number of broad s o i l landscapes defined at the s o i l great group l e v e l (C.S.S.C., 1978). Each i s defined as "the t o t a l ecosystem with which a s o i l i s associated, with emphasis placed on the s o i l i t s e l f " (Valentine et a l . , 1978). The study area f a l l s within the Ferro-Humic Podzol and the Humo-Ferric Pod-z o l s o i l landscapes (Jungen and Lewis, 1978). The Ferro-Humic Podzol s o i l landscape occurs on the windward side of Vancouver Island. This area i s characterized by abundant r a i n f a l l and moist, r a r e l y frozen s o i l s throughout most of the year (Jungen and Lewis, 1978). The main s o i l formation processes are the accumulation of organic matter, i r o n , and aluminum producing s o i l with d i s t i n c t podzolic Bfh horizons. Continuous seepage i s present throughout most of t h i s s o i l landscape, and i s r e f l e c t e d by the high organic matter content of the s o i l s , rather than the t y p i c a l mottling and gleying (Jungen and Lewis, 1978). Organic matter content often reaches a maximum, sometimes over 30 %, near the lower part of the p r o f i l e (Jungen and Lewis, 1978). The presence of a cemented, indurated pan (Be horizon) i s the major c h a r a c t e r i s t i c of morainal s o i l s (Jungen and Lewis, 1978). In these s o i l s the Bhf horizon commonly i s most pronoun-ced j u s t above the cemented t i l l which often cannot be broken with a shovel. Morainal s o i l s are mostly imperfectly to poorly drained while c o l l u v i a l s o i l s , with no cementation, are generally w e l l to moderately well drained (Jungen and Lewis, 1978). Organic horizons between 20 to 40 cm thick frequently were observed on Ferro-Humic Podzols within the study area. Valentine (1971) noted the high organic matter content of 18 the s o i l surface layers of the Tofino-Ucluelet lowland. He suggested that dense vegetation coupled with moderate temperatures, allowing nearly continuous b i o l o g i c a l and chemical a c t i v i t y , forms a "constant source of raw humic material". Most plant nutrients may be derived from t h i s organic matter (in organic horizons and upper mineral horizons) rather than from the mineral solum (Valentine, 1971). Valentine (1971) also noted a generally shallow rooting zone even under dense tree growth. The importance of the organic layers i n nutrient c y c l i n g i n s o i l s of the west coast of Vancouver Island i s also supported through the recent discovery of an endemic earthworm (Arctiostrotus s i m p l i c i g a s t e r vancou- verensis) (Spiers et aJ_. , 1984) . This worm may play a major r o l e i n mediating nutrient c y c l i n g within the organic layers where i t i s res-t r i c t e d (Spiers et a l . , 1984). Chemically the s o i l s of the Ferro-Humic Podzol s o i l landscape have a very low base saturation, low pH (commonly < 5.0), and high organic carbon, i r o n , and aluminum contents (Jungen and Lewis, 1978). The Humo-Ferric Podzol s o i l landscape occurs far t h e r inland within the study area, e s p e c i a l l y around Port A l b e r n i . S o i l moisture i s not as abundant as i n the Ferro-Humic Podzol s o i l landscape owing to the warmer and d r i e r summer climate (Jungen and Lewis, 1978). C o l l u v i a l and morainal parent materials are common, the l a t t e r usually with a weakly to strongly cemented pan (Be and Bcc horizons). Cementation, when present, i s usu-a l l y strongest near the top of the pan (Jungen and Lewis, 1978). C o l l u v i a l s o i l s .often are deeply weathered, well to r a p i d l y drained, and contain no signs of cementation (Jungen and Lewis, 1978). Chemically these s o i l s have low pH (4.0 to 5.0), moderate to high i r o n and aluminum content, 19 and low base saturation (Jungen and Lewis, 1978). In contrast with the s o i l s of the Ferro-Humic Podzol s o i l landscape, Humo-Ferric Podzol s o i l s have l i t t l e organic matter accumulation i n the upper B horizons (Valen-t i n e and Lavkulich, 1978). Apart from podzols, other s o i l orders are also encountered within the study area. F o l i s o l s , c o n s i s t i n g of shallow organic material over-l y i n g bedrock, are sometimes found on rock outcrops i n high'„.rainfall areas near the coast. Orthic regosols occur on floodplains and on rock outcrops. Gleyed Sombric Brunisols frequently are found on floodplains. Humic Gleysols are most frequent i n plots of the Estevan Coastal P l a i n . Some Dy s t r i c Brunisols also occur i n the d r i e r inland part of the study area. Other than F o l i s o l s , organic s o i l s occasionally are found i n bedrock depressions and i n areas overlying impervious s u r f i c i a l m a t e r i a l ; examples of the l a t t e r include the bogs on marine clays i n the Tofino-Ucluelet area (Valentine, 1971). The t y p i c a l Vancouver Island podzol was reported by Lewis (1976) to be d i f f e r e n t from the c l a s s i c podzolic p r o f i l e . Frequently, no e l u -viated Ae horizon i s found. Despite the strong leaching, the constant addition of abundant organic matter and the constant weathering of i r o n and aluminum i n the upper mineral horizon prevent the net depletion necessary to form an Ae horizon (Lewis, 1976; Valentine and Lavkulich, 1978); however, i t was also reported that an accumulation of organic matter may sometimes mask the Ae horizon under moist f i e l d conditions (Valentine and Lavkulich, 1978). S o i l s derived from b a s a l t i c and ande-s i t i c parent materials have no Ae horizons because they contain no s i l i c a 20 to be l e f t behind a f t e r weathering (Lewis, 1976). Throughout the study area s o i l horizon boundaries frequently are very i r r e g u l a r because of the t u r b i c a c t i v i t y associated with windthrow. Most s o i l s sampled, e s p e c i a l l y those on c o l l u v i a l material, were coarse textured and contained a high percentage of large rock fragments. O v e r a l l , the pH values of organic horizons v a r i e d from 3.0 to 6.2 (H2O), and the pH values of the upper mineral horizons (mostly Bj) from 3.8 to 6.3 (H2O). T o t a l nitrogen in the upper mineral horizons varied from 0.02 % to 0.86 %, t o t a l carbon from 0.2 % to 24.4 %, and C/N r a t i o s from 10 to 94. 21 C. CLIMATE Climatic data are a v a i l a b l e from several low elevation permanent weather stations within the study area (Anonymous, 1982); high eleva-tion stations are lacking. Most of the study area f a l l s within the humid mesothermal summer-wet climate (Cfb) according to the KOppen sys-tem. This i s described by Strahler (1965) as a windward, west coast climate with moist maritime polar a i r masses h i t t i n g the coast with f r e -quent eastward-moving cy c l o n i c storms. P r e c i p i t a t i o n tends to be evenly d i s t r i b u t e d throughout the year, but there i s a winter maximum. The annual temperature range i s small f o r middle l a t i t u d e s (Strahler, 1965). The a i r masses c o l l e c t moisture as they pass over the warm Alaska current and release i t as orographic p r e c i p i t a t i o n over the land. A d i s t i n c t i v e r a i n shadow e f f e c t i s . c r e a t e d on leeward mountain slopes and v a l l e y s . The d r i e s t part of the Port A l b e r n i area as well as a l l of the southeast coast of Vancouver Island can be c l a s s i f i e d as a humid mesothermal, summer-dry climate (Csb). This summer-dry, winter-wet climate, predo-minant far t h e r south along the P a c i f i c Coast, i s caused by the replace-ment of c y c l o n i c , moist maritime polar a i r masses (Aleutian Low) by a r e l a t i v e l y stable, dry maritime t r o p i c a l a i r mass (North P a c i f i c High) during the summer (Strahler, 1965). Southern B r i t i s h Columbia i s at the northernmost l i m i t of the influence of t h i s system, and r a i n f a l l d i f f e -rences between the west and east coasts of Vancouver Island are i n a large part due to orographic e f f e c t s . 22 Climatic data from Tofino A i r p o r t (Fig. 2) are c h a r a c t e r i s t i c of the Cfb climate within the study area. P r e c i p i t a t i o n averages 3288 mm annually, but windward slopes east of Tofino l i k e l y receive more. Abun-dant moisture i s always a v a i l a b l e f o r plant growth. Dry mineral s o i l or humus was never observed i n summer near the coast, except sometimes on rock outcrops. The temperature i s very mild, with the mean d a i l y minimum of the coldest month at 0.8°C, and the mean d a i l y maximum of the warmest month at 18.3° C; the mean annual temperature i s 8.9°C (Fig. 2). The Lupsi Cupsi c l i m a t i c s t a t i o n near Port A l b e r n i (Fig. 2) i s at the wetter l i m i t s of a Csb climate. Mean annual p r e c i p i t a t i o n i s 1929 mm, and a period of moisture d e f i c i t i s experienced i n mid-summer when the average monthly p r e c i p i t a t i o n reaches 28 mm (Fig. 2). The temperature also i s very mild, although a s l i g h t continental!ty e f f e c t i s noticeable with a lower mean d a i l y minimum temperature of the coldest month (-1.1°C), and a higher mean d a i l y maximum temperature of the warmest month (24.6°C), than at Tofino. The mean annual temperature at Port A l b e r n i i s 9.5°C. Snowfall makes up 5 % of the mean annual p r e c i p i t a t i o n at Port A l b e r n i and less than 2 % at Tofino (Anonymous, 1982). O r l o c i (1964) considered snow duration and accumulation to be an i n s i g n i f i c a n t e c o l o g i c a l f a c t o r at low elevation. In contrast, at higher elevations, cooler tempera-tures (Dfc, microthermal snowy climate) r e s u l t i n a larger percentage of p r e c i p i t a t i o n i n the form of snow. Hollyburn Ridge (951 m) near Vancou-ver receives close to 3000 mm of p r e c i p i t a t i o n annually, of which 28 % f a l l s as snow (Brooke et^ a l . , 1970). Heavy snowpacks of moist snow often l i n g e r into mid-summer above 1000 m. Snow depths averaged 3 m over seve-r a l years on A p r i l 1 s t surveys of the north shore mountains near Vancouver (Brooke et a l . , 1970). 23 The occurrence of summer fog, p a r t i c u l a r l y i n areas nearest to the coast, i s another important c l i m a t i c f a c t o r within the study area. Summer fog i s formed off the coast of Vancouver Island and moves inland towards a low pressure area created by the d a i l y warming of the land mass. This fog usually covers the Estevan Coastal P l a i n up totthe f i r s t mountain slopes. Azevedo and Morgan (1974) have described a s i m i l a r phenomenon fo r north-coastal C a l i f o r n i a . Their data show the predominance of fog at night, d i s s i p a t i n g during the day. In the study area, as i n northern C a l i f o r n i a , fog could l a s t a l l day during p a r t i c u l a r l y heavy episodes, and the fog would d i s s i p a t e l a s t nearest to the coast. Fog often appeared i n the Tofino-Ucluelet area during summer days which were warm and clear for the rest of the study area. Fog d r i f t i n g through f o r e s t canopies has been shown to cause considerable amounts of p r e c i p i t a t i o n as fog drip (Azevedo and Morgan, 1974). A large portion of t h i s p r e c i p i t a t i o n i s probably unrecorded by standard weather s t a t i o n s , but the vegetation should c e r t a i n l y r e f l e c t the prevalence of summer fog (Azevedo and Morgan, 1974). Climatic maps compiled by Colidago (1980) f o r southern Vancouver Island reveal a complex pattern of decreasing summer p r e c i p i t a t i o n and increasing e f f e c t i v e growing degree-days as distance from the coast i n -creases (Fig. 12). The. "freeze-free" period (mean d a i l y temperature > 0°C) va r i e s from 240 days at low elevation on the coast near Tofino, to 160 days inland near Port A l b e r n i (Colidago, 1980). 24 D. VEGETATION Most of the study area f a l l s within the Coastal Western Hemlock biogeoclimatic zone of B r i t i s h Columbia (Krajina, 1965; 1969). The vegetation of a small area surrounding Port A l b e r n i has been placed within the wetter subzone of the Coastal Douglas-fir biogeoclimatic zone (Klinka et a l . , 1979). Klinka et a l . (1979) recognize several subzones and variants of these two biogeoclimatic zones within the study area. Subalpine f o r e s t s , generally above 1000 m elevation, belong to the Moun-tain Hemlock biogeoclimatic zone (Krajina, 1969; K l i n k a jilt al. , 1979), or to the Coastal section (SA.3) of the Subalpine f o r e s t region (Rowe, 1972). The lower elevations of the study: area are within the Coast forest region of Rowe (1972). The d r i e r Port A l b e r n i area supports vegetation s i m i l a r to the S t r a i t of Georgia section (C.l) through the presence of Arbutus menziesii, the only broadleaf evergreen tree i n Canada, and the dominance of Pseudotsuga menziesii i n the landscape (Rowe, 1972). The adjacent Southern P a c i f i c Coast section (C.2) contains most of the study area and i s characterized by stands, often even-aged, dominated i n decreasing order by Pseudotsuga menziesii, Tsuga hetero- p h y l l a , and Thuja p l i c a t a on well drained s i t e s . On v a l l e y f l o o r s or on moist, sheltered slopes Pseudotsuga menziesii i s sometimes absent while Tsuga heterophylla, Thuj a p l i c a t a , and Abies amabilis increase i n impor-tance. These differences indicate,the e s s e n t i a l l y s e r a i character of Pseu-dotsuga menziesii in t h i s section (Rowe, 1972). Thuja p l i c a t a dominance i s associated with seepage areas, while Abies amabilis increases i n 25 abundance with increasing elevation (Rowe, 1972). The Estevan Maritime Coastal Western Hemlock biogeoclimatic variant of Klinka et a l . (1979) corresponds approximately to the Vancouver Island portion of Rowe's (1972) Northern P a c i f i c Coast section (C.3). In t h i s section, Tsuga  heterophylla and Abies amabilis dominate on r a r e l y occurring well drained s i t e s , while Thuja p l i c a t a becomes dominant everywhere else where d r a i -nage i s d e f i c i e n t (Rowe, 1972). Picea s i t c h e n s i s i s found mostly on a l l u v i a l deposits and on the coastal f r i n g e (Cordes, 1972). Because of the very humid climate, f o r e s t f i r e s are rare within t h i s section and the major source of f o r e s t disturbance i s wind (Rowe, 1972; Klinka et a l . , .1979). Pseudotsuga menziesii i s v i r t u a l l y absent within the section (Rowe, 1972). The most productive stands are produced following wind-throw (Rowe, 1972; Klinka et^ a l . , 1979). Some very productive stands also were observed on ancient avalanche colluvium within t h i s section of the study area. The Coastal Western Hemlock biogeoclimatic zone (Krajina, 1969), or the Southern P a c i f i c Coast section of the Coastal f o r e s t region (Rowe, 1972), have growing conditions s u i t a b l e for the highest forest produc-t i v i t y i n Canada. In some s i t e s of the D r i e r Coastal Western Hemlock biogeoclimatic subzone, Pseudotsuga menziesii reaches the maximum growth attained by any tree on any s i t e i n Canada (Site Indexjoo • 54-60 m) (Krajina, 1969). The vascular f l o r i s t i c patterns and a f f i n i t i e s of coastal B r i t i s h Columbia are discussed by Schofield (1969) and Scoggan (1978). The bryo-f l o r a has been analysed i n more d e t a i l by Schofield (1965, 1968a, 1968b, 26 1969, 1976, 1980, 1984). Many dominant taxa within the study area are r e s t r i c t e d to the r e l a t i v e l y narrow Coastal or C o r d i l l e r a n area along western North America. Several P a c i f i c North American taxa such as Arbutus menziesii, Arctostaphylos columbiana, and Oxalis oregana reach the northern extent of t h e i r ranges near the study area. 27 CHAPTER 3. METHODS A. DATA COLLECTION 1. LOCATION OF PLOTS The s e l e c t i o n of sampling s i t e s over a large, mountainous and heterogeneous area, for the purpose of gradient analysis and ordination, requires a minimum of bia s , adequate representation of the range of v a r i a t i o n i n environment and community composition, homogeneity within sampling u n i t s , lack of disturbance, and a s u f f i c i e n t l y large sample (whittaker, 1978). Because of the d i f f i c u l t y of s e l e c t i n g p l o t s without bias, random sampling i s often recommended for vegetation studies (Smartt and Grainger, 1974). However, formal randomization i n large scale studies has been rejected by most researchers (Moore et a l . , 1970), with some exceptions (Noy-Meir, 1971), because of drawbacks such as i n e f f i c i e n c y (for time and sample size) and inadequate representation of v a r i a t i o n ranges, because of the high p r o b a b i l i t y of missing many unusual, and often very i n f o r -mative, communities (Whittaker, 1978; Peet, '1981). The random l o c a t i o n of p l o t s i n the f i e l d may be time consuming and y i e l d many unsatisfactory s i t e s (because of heterogeneity or disturbance, e s p e c i a l l y i n an area with a c t i v e logging such as i n t h i s study). Subjective sampling can y i e l d a much broader spectrum of vegetational v a r i a t i o n i n the same amount of time (Peet, 1981), and the time saved i n p l o t l o c a t i o n w i l l permit the c o l l e c t i o n of a larger sample. In order to make the pl o t l o c a t i o n selec-t i o n as objective as possi b l e , the study area was subdivided into t h i r t e e n 28 drainage areas (Fig. 3). The number of plot s sampled i n each area depended on the size of the area and on a c c e s s i b i l i t y . Some drainage areas with very d i f f i c u l t access were not sampled. Within each selected drainage area an e f f o r t was made to sample examples of a l l topographic pos i t i o n s (slopes, ridges, f l o o d p l a i n s , etc.) and edaphic conditions present, up to an elevation of about 1000 m, reportedly the lower l i m i t of the Mountain Hemlock biogeoclimatic zone (Brooke et^ a l . , 1970; Kli n k a et a l . , 1979). Also, only homogeneous (within p l o t boundaries) old-growth forests with no evidence of major disturbance within the l a s t hundred years were sampled. The maximum ages of stands sampled varied from 150 years to well over 500 years, with a few exceptions. Coastal f r i n g e communities of Picea s i t c h e n s i s , influenced by ocean spray, and Sphagnum bogs, on deep organic s o i l s , were not sampled. These s p e c i a l plant communities have been studied by Cordes (1972) and Wade (1965), r e s p e c t i -vely. Sand dune vegetation of Long Beach, P a c i f i c Rim National Park, was studied by Kuramoto (1965). 2. VEGETATION SAMPLING The vegetation was sampled within a c i r c u l a r 500 m2 p l o t ( P f i s t e r and Arno, 1980) at each s i t e . From a centre-point., two tapes were l a i d out at 90 degrees, and a radius distance of 12.6 m was flagged around the p e r i -phery of the p l o t , using c a l i b r a t e d ropes (Fig. 4). The diameters at breast height (1.3 m) of a l l stems within the plo t were recorded for each species i n 10 cm s i z e - c l a s s e s . Stems over 10 cm DBH are re f e r r e d to as trees, and stems between 0 and 10 cm DBH are ref e r r e d to as saplings. 29 The understory vegetation and tree seedlings ( a r b i t r a r i l y defined as stems less than 1.3 m t a l l ) were recorded i n twenty 1 m2 microplots. Two d i f f e r e n t microplot placement designs were used : a systematic design for p l o t s 1 to 61 (1980) and a s t r a t i f i e d random design for p l o t s 62 to 172 (1981) (Fig. 4). Randomization avoided the sampling bias toward the centre of the p l o t , inherent i n the systematic design, and yielded data that were more amenable to s t a t i s t i c a l i n t e r p r e t a t i o n . The s t r a t i f i e d random design was obtained by determining from a table of random numbers f i v e microplot locations on a g r i d of each quarter of the plot surface. This design was repeated i n the sampling of p l o t s 62 to 172. Percent coverage was estimated for shrubs, herbs, bryophytes and lichens, i n each microplot, using a seven-point scale of coverage ranges s i m i l a r to that of Daubenmire (1968) : 1 (0-1 % ) , 2 (1-5 % ) , 3 (5-25 % ) , 4 (25-50 % ) , 5 (50-75 %) , 6 (75-100 %) and 7 (100 % ) . Also, the numbers of tree seedlings were recorded by species within the microplots. Vascu-l a r species.not encountered within the microplots but found within the larger 500 m2 p l o t were recorded as present, and a r b i t r a r i l y assigned values of 0.01 percent coverage and 1.0 % frequency; non-vascular species outside the microplots were not recorded. These measurements provide for each pl o t : basal area (or domi-nance) of trees, density of trees, density of saplings, density of seed-l i n g s , and percent coverage (average of 20 microplots).and frequency (over 20 microplots) for shrubs, herbs, bryophytes and l i c h e n s . The heights of at l e a s t two dominant trees were measured i n each pl o t using a clinometer, and the maximum height of the shrub and herb s t r a t a recorded. Cores of two of the largest trees, of d i f f e r e n t species, were taken for stand age estimates. 30 3. SOIL AND ENVIRONMENTAL DATA Within each 500 m2 p l o t a s o i l p i t was dug to bedrock, to a layer of compacted t i l l , or to a depth of one metre, whichever came f i r s t . A s o i l p r o f i l e d e s c r i p t i o n was written i n the f i e l d and samples of each organic and mineral horizon were taken for laboratory analyses. The f i e l d d e s c r i p t i o n included features such as, horizon thickness, percent coarse fragments, f i e l d texture (estimated), structure, consistency, charcoal presence, colour, abundance and s i z e of roots, and organic material d e s c r i p t i o n . Other s i t e and s o i l data such as elevation, aspect, percent slope, topographic p o s i t i o n , surface shape, s o i l d r a i -nage, estimated s o i l moisture regime, nature of s u r f i c i a l material, nature of bedrock, evidence of f i r e and w i n d f a l l , and presence of earth-worms (plots 62 to 172) were also recorded. The distance of each pl o t from the P a c i f i c Ocean was determined from a map. The s o i l analyses were performed by the MacMillan Bloedel Wood-lands Services S o i l Laboratory, generally following the U.B.C. Pedology Methods Manual (Lavkulich, 1978). A l l samples were a i r dried. A f t e r drying, organic samples were ground i n a Wiley m i l l to pass through a 20-mesh screen, and mineral samples were passed through a 2 mm sieve and ground to pass a 60-mesh screen. The pH's of a l l samples were determined i n both a 1:1 water suspension (1:2 for organics) and 1:2 0 . 0 1 M CaCl2 suspension (1:4 for organics). S o i l texture was determined by the hydro-meter method f or the top B horizon of plot s 1 to 61. Tot a l organic carbon content was determined by the Walkley-Black method of Wet Oxidation. The t o t a l nitrogen content of samples was determined using a Technicon Auto 31 Analyser II a f t e r digestion i n sulphuric acid and c a t a l y s t s (mineral samples), or a f t e r digestion i n 30 % hydrogen peroxide and sulphuric acid (organic samples). The determinations of pH, t o t a l carbon (%) and t o t a l nitrogen (%) were chosen because these s o i l properties show the least w i t h i n - s i t e v a r i a b i l i t y and are therefore more r e l i a b l e when only one sample per s i t e i s taken (Quesnel and Lavkulich, 1980). 4. NOMENCLATURE The taxonomic nomenclature of t h i s study generally follows Scoggan (1978-1979) for vascular plants, Ireland et a l . (1980) for mosses, S t o t l e r and C r a n d a l l - S t o t l e r (1977) for liverworts, and Hale and Culberson (1970) for li c h e n s . In a few cases the names used i n t h i s study are l i s t e d as syno-nyms by the taxonomic sources. Voucher specimens for most vascular plants and a l l non-vascular plants are deposited at the Uni v e r s i t y of B r i t i s h Columbia's Botany Department Herbarium (UBC). 32 B. DATA ANALYSIS 1. GRADIENT ANALYSIS AND ORDINATIONS a) Indirect gradient analysis and ordinations Gradient analysis i s an approach to the study of vegetation that seeks to explain the s p a t i a l d i s t r i b u t i o n and v a r i a t i o n of vegetation i n terms of three sets of v a r i a b l e s , (1) environmental f a c t o r s , (2) species populations and (3) community c h a r a c t e r i s t i c s (Whittaker, 1967). This approach i s based on the view of vegetation as a continuum (Gleason, 1926; Mcintosh, 1967; Whittaker, 1967) where "vegetation i s considered as a continuously varying, stochastic phenomenon wherein plants respond i n d i v i d u a l i s t i c a l l y to environmental conditions" (Peet, 1981). Indirect gradient a n a l y s i s , or i n d i r e c t ordination (Whittaker, 1978), i s a tech-nique which attemps to i d e n t i f y major environmental gradients underlying the patterns of vegetation v a r i a t i o n . Such patterns are g r a p h i c a l l y i l l u s t r a t e d by ordinations of p l o t s obtained by analysing data on species composition. Thus, an important assumption of i n d i r e c t ordination i s that trends i n environmental gradients w i l l be r e f l e c t e d by trends i n vegeta-t i o n v a r i a t i o n (Whittaker, 1978). Reciprocal averaging ( H i l l 1973, 1974), a type of standardized p r i n c i p a l components analysis was the ordination technique used i n t h i s study. In t e s t s , Gauch et^ a l . (1977) have shown i t to be one of the best a v a i l a b l e techniques i n exposing environmental gradients using vegetation data where these gradients were already known. Although d i s t o r t i o n can present a problem i n axis s c a l i n g , the method r e l i a b l y y i e l d s a primary axis of v a r i a t i o n which i s e c o l o g i c a l l y 33 i n t e r p r e t a b l e . When the primary axis of v a r i a t i o n corresponds to a par-t i c u l a r l y strong environmental gradient (Fig. 10), the second axis i s often correlated with the f i r s t , causing an "arch e f f e c t " (Gauch et a l . , 1977). Experience with t h i s study's and other data sets indicates that the e c o l o g i c a l s i g n i f i c a n c e of the second axis diminishes with increasing strength of the primary environmental gradient, usually i d e n t i f i e d by the ordination's f i r s t axis (Gauch et a l . , 1977; Peet, 1980). In such cases the t h i r d axis often represents more accurately a second major environmental gradient, while the percentages of v a r i a t i o n explained by the second and t h i r d axes are nearly equal. Detrended correspondance ana l y s i s , a recent modification of r e c i p r o c a l averaging, i s reported to overcome t h i s problem ( H i l l and Gauch, 1980). Random species f l u c t u a -tions create noise i n community data. Gauch (1982) estimates t h i s noise to be on the order of 10 to 50 % of the t o t a l variance i n the data. Simulation experiments have shown that eigenvector ordination s e l e c t i -vely recover meaningful patterns of c o r r e l a t i o n among several species i n the f i r s t few ordination axes, while s e l e c t i v e l y deferring noise to l a t e r axes (Gauch, 1982). This would help to explain the observation that, i n general, ordinations of f i e l d data are frequently u s e f u l even when the percentage of variance explained by the f i r s t few axes i s small (Gauch, 1982). This also explains the common observation that meaningful ecolo-g i c a l i n t e r p r e t a t i o n s of ordinations axes are d i f f i c u l t past the second or t h i r d a x i s , with some exceptions (Noy-Meir, 1971). The goal of o r d i -nation has been viewed as accounting for most of the o r i g i n a l data variance i n the fewest ordination axes, but f i e l d data usually contains x % "noise variance" and (100-x) % "structure variance" (Gauch, 1982). Thus the 34 goal should be to recover (100-x) %. of the variance, preferably only the structure variance to the exclusion of noise variance (Gauch, 1982). Since noise variance has been estimated to be from 10 to 50 %, recovery of 100 % of the variance implies that the ordination has f a i l e d i n noise reduction. A major d i f f i c u l t y with t h i s viewpoint i s i n deciding what i s "structure variance" and what i s "noise variance", anything which can be interpreted becomes "structure variance" and whatever cannot be i n t e r -reted becomes "noise variance". P r i n c i p a l components analysis ordinations based on species covariance and c o r r e l a t i o n matrices were also t r i e d , but did not produce superior r e s u l t s to r e c i p r o c a l averaging. An advantage of r e c i p r o c a l averaging i s that i t simultaneously produces a species ordination which can be superimposed on the sample ordination (Greenacre, 1981). This can be very h e l p f u l i n displayingivegetation trends as cha-r a c t e r i z e d by major species. The Wisconsin double standardization of data, sometimes recommended for use with RA (Peet, 1981), was not done since the program used included a form of double standardization i n the c a l c u l a t i o n of resemblance c o e f f i c i e n t s . Species present i n less than four or three p l o t s , depending on matrix s i z e , were removed for the ana-lyses. Rare species contribute l i t t l e information to o v e r a l l p l o t s i m i -l a r i t i e s , and often cause the p l o t s containing them to be markedly i s o -lated i n , r e c i p r o c a l averaging ordinations. The vegetation data analysed i n t h i s study are based on r e l a t i v e importance values of trees (> 10 cm DBH), r e l a t i v e density of saplings (0-10 cm DBH) and seedlings (below breast height), and percent coverage of shrubs, herbs, bryophytes and t e r r i c o l o u s l i c h e n s . Before t h i s combination of abundance measures and s t r a t a was chosen, several t r i a l ordinations were run. Trees were 35 ordinated alone using three d i f f e r e n t abundance measures, which, i n decreasing order of ordination i n t e r p r e t a b i l i t y they provided, were rated as follows : importance value > r e l a t i v e dominance > r e l a t i v e density. Relative importance value ( [ r e l a t i v e dominance + r e l a t i v e density ]/2) i s appropriate when tree species occur i n a wide range of maximum sizes and d e n s i t i e s . In t h i s study, r e l a t i v e dominance overem-phasized the importance of a few very large trees, such as Thuja p l i c a t a and Pseudotsuga menziesii, while smaller, often more numerous, trees, such as Tsuga heterophylla and Abies amabilis, were underrated. Rela-t i v e density created the reverse problem. Relative density was selected instead of absolute density for saplings and seedlings since, espe-c i a l l y for seedlings, absolute density values varied enormously between p l o t s . The use of d i f f e r e n t s i z e - c l a s s e s of trees (trees, saplings, seedlings) o f f e r s p o t e n t i a l for regrouping samples with s i m i l a r regene-r a t i o n trends; thus, differences i n canopy dominants, which may have arisen through d i f f e r e n t disturbance regimes i n the past, are o f f s e t by s i m i l a r patterns of regeneration i n the understory. Several authors have used t h i s technique for s i m i l a r purposes (Goff and Zedler, 1972; Peet and Loucks, 1977; Carleton and Maycock, 1978). The d i f f e r e n t s i z e -classes of a tree species are treated as d i f f e r e n t "pseudo-species" (Carleton and Maycock, 1980) f o r the purpose of the ordinations. A seedling s i z e - c l a s s was used here despite the "highly stochastic nature of establishment and s u r v i v a l (of seedlings) for the f i r s t few-years" (Peet and Louck, 1977). Although t h i s was observed i n the widely f l u c -tuating absolute d e n s i t i e s of seedlings among p l o t s , i t was f e l t that the r e l a t i v e density of seedlings of a p a r t i c u l a r species, with differences 36 i n reproductive p o t e n t i a l and l i f e h i s t o r y patterns taken into account, remains a good i n d i c a t o r of that species' p o t e n t i a l r o l e i n the future composition of the stand, as w e l l as a good i n d i c a t o r of present ecolo-g i c a l conditions. Comparisons of ordinations obtained with and without tree s i z e - c l a s s data have shown that better r e s u l t s are obtained using t h i s technique where (1) dominant tree species are numerous, (2) rege-nerating tree species are few, (3) successional stands are common, and (4) environmental d i v e r s i t y of the study area i s small. These conditions were met i n an e a r l i e r study (Gagnon and Bouchard, 1981). In the present study however, the canopy dominants are few and nearly a l l are regene-r a t i n g i n some stands. Futhermore, most stands are i n l a t e stages of development (although many are dominated by P_. menziesii, a long-lived successional species), and environmental d i v e r s i t y i s great. Despite these drawbacks, the use of tree s i z e - c l a s s e s provided a clearer sepa-r a t i o n of some e c o l o g i c a l l y d i f f e r e n t communities with s i m i l a r canopies (eg. montane vs_ lowland Abies f o r e s t s ) . The most interpretable ordina-t i o n r e s u l t s were obtained using data from shrub, herb and bryophyte-l i c h e n s t r a t a along with tree data separated into three s i z e - c l a s s e s . Peet (1981), studying the vegetation of the Colorado Front Range, and Beese (1981), the vegetation of eastern Vancouver Island, have reported greater success with ordinations of understory data only. In both areas the tree layer was not considered the i d e a l s i t e i n d i c a t o r since i t l a r g e l y r e f l e c t e d past disturbances. To a c e r t a i n extent t h i s was also the case i n t h i s study, but the p a r t i t i o n i n g of tree data i n t o s i z e -classes greatly improved the ordinations. 37 b) Successive ordinations Plots that d i f f e r markedly i n composition from the majority of p l o t s are usually placed toward the ends of ordination axes. Evidence from tests (Gauch e_t a l . ,.1977) and personal experience indicates that r e c i p r o c a l averaging i s p a r t i c u l a r l y s e n s i t i v e to o u t l i e r p l o t s . O u t l i e r s are defined as p l o t s of unusual composition r e l a t i v e to the majority of p l o t s i n the sample (Gauch et a l . , 1977). More s p e c i f i c a l l y , o u t l i e r s may have (a) unusual combinations of species importances, (b) one or a few species dominating strongly, or (c) several species which are un-common and unimportant elsewhere within the matrix. O u t l i e r s of type "a" and "b" are sometimes caused by sampling e r r o r , or by the sampling of disturbed or environmentally unusual s i t e s , and are problematic i n the i n t e r p r e t a t i o n of ordinations (Gauch et_ a l . , 1977). Type "c" out-l i e r s can be used to advantage i n ordination i n t e r p r e t a t i o n . In large or complex data sets successive ordinations can permit the segregation of groups or types of communities at the periphery of the ordination f i e l d . This progressive fragmentation of the data set s u p e r f i c i a l l y resembles c l a s s i f i c a t i o n , but the objective i s to understand the environ-mental r e l a t i o n s h i p s between groups of s i m i l a r p l o t s (Peet, 1980). Ordi-nation i s thus used as a c l a s s i f i c a t i o n t o o l i n which d i s t i n c t i v e groups are removed successively from the data a f t e r the r e s u l t i n g patterns have been examined for environmental c o r r e l a t i o n s . I f large enough, the groups removed may also be ordinated to reveal within group patterns and envi-ronmental c o r r e l a t i o n s . In t h i s study, from an i n i t i a l ordination of the t o t a l 172 plots'sample, three environmentally d i s t i n c t groups of com-munities, plus a v e g e t a t i o n a l l y d i s t i n c t community type (PI), were 38 segregated from a c e n t r a l cloud of p l o t s . An ordination of the remaining p l o t s indicated that they could be p a r t i t i o n e d again into three environ-mentally and geographically d i s t i n c t groups. Ordinations of each of these l a t t e r groups allowed several community types to be delineated along d i s t i n c t environmental gradients. Product moment c o r r e l a t i o n s were calculated between sample scores on ordination axes, environmental variables (Table 1), and community c h a r a c t e r i s t i c s (Table 2) to help i d e n t i f y gradients underlying the vegetation patterns i l l u s t r a t e d by the ordinations. Lack of strong c o r r e l a t i o n s with any single v a r i a b l e may indica t e that "complex" environmental gradients (Whittaker, 1978) c o n t r o l the v a r i a t i o n of the vegetation. A topographic-moisture gradient i s "complex" i n the sense that i t combines the e f f e c t s of slope and aspect, as well as topographic p o s i t i o n , s o i l texture and drainage. Thus, complex master environmental gradients might show strong c o r r e l a t i o n s with o r d i -nation axes, i f they could be expressed q u a n t i t a t i v e l y . A further ordination analysis was done i n order to i d e n t i f y major environmental gradients i n f l u e n c i n g the vegetation pattern at the l e v e l of the e n t i r e study area, without the noise introduced by edaphic v a r i a -t i o n s . For t h i s purpose, 105 vegetation p l o t s of modal s i t e s were ana-lysed with a r e c i p r o c a l averaging ordination. Excluded from t h i s ana-l y s i s were p l o t s from high elevations,,lower slopes of steep r i v e r v a l l e y s (cold a i r drainage or snow accumulation), rock outcrops, very r a p i d l y and very poorly drained s i t e s , and f l o o d p l a i n s . Correlations of ordina-t i o n axes with environmental v a r i a b l e s and community c h a r a c t e r i s t i c s were used to i d e n t i f y the environmental gradients underlying the modal vegetation pattern. The r e c i p r o c a l averaging and p r i n c i p a l components 39 analysis programs used were developed by Dr. G.E. Br a d f i e l d following O r l o c i (1978). Product moment co r r e l a t i o n s were produced using the MIDAS s t a t i s t i c a l package supported by the Univ e r s i t y of B r i t i s h Colum-bi a Computing Centre. c) Direct gradient analysis Direct gradient a n a l y s i s , or d i r e c t ordination, r e f e r s to the arrangement of plot s along one or more known, or accepted as given, environmental gradients (Whittaker, 1967, 1978). These gradients may be derived e m p i r i c a l l y , surmised from observation, or i d e n t i f i e d through c o r r e l a t i o n of environmental v a r i a b l e s with i n d i r e c t ordination axes. Direct ordinations were used to display the s p a t i a l d i s t r i b u t i o n of communities along topographic-moisture and elevation gradients within three f a i r l y homogeneous vegetation groups. The topographic-moisture gradient used here i s s i m i l a r to gradients u t i l i s e d by Whittaker (1956), Whittaker and Neiring (1965) and Peet (1981), but p a r t i c u l a r l y resembles that used by Whittaker (1960) i n his study of the Siskiyou Mountains of Oregon. The mesic, or moist, end of the gradient i s represented by stands found on l e v e l , or near l e v e l , ground, proceeding to stands found on lower-slopes, where moisture i s provided by seepage, but where drainage i s better than on l e v e l ground. Further towards the x e r i c or dry end of the gradient are located stands from mid-slopes and upper-slopes. The xe r i c endpoint i s formed of stands situated on cr e s t s , ridges or dry summits. Stands situated on sloping ground are arranged i n two categories, (a) lower-slopes and (b) mid-slopes and upper-slopes, according to t h e i r 40 aspect. The lower-slope range i s shortened because aspect e f f e c t s are not as important for these stands with increased shelter and moisture a v a i l a b i l i t y . The two slope ranges do not overlap as i n Whittaker (1960). One Pinus contorta type was included with the Pseudotsuga group, and one with the Thuja group, i n the d i r e c t ordination figures because of t h e i r f l o r i s t i c and geographical a f f i n i t i e s with these groups. The p l o t t i n g of species abundance or community c h a r a c t e r i s t i c s along environmental gradients i s a v a r i a t i o n of d i r e c t gradient analysis. In t h i s study geographical coordinates were used as complex environ-mental gradients combining v a r i a t i o n s i n temperature, p r e c i p i t a t i o n and c o n t i n e n t a l i t y . This approach i s h e l p f u l i n i d e n t i f y i n g r e l a t i o n s h i p s of vegetation and s o i l s with geographical patterns. This was p a r t i c u -l a r l y u s e f u l for data obtained from other sources, such as c l i m a t o l o g i c a l data. In another type of a p p l i c a t i o n , the basal area data of tree spe-cies from the 105 modal plo t s were pl o t t e d against a geographical gra-dient defined by the distances of these p l o t s from the Ocean. The SPSS polynomial regression program was used to obtain equations describing the basal area d i s t r i b u t i o n of tree species along t h i s gradient. 41 2. TYPE DELIMITATION a) D e f i n i t i o n of groups and types Ordination techniques were used to a s s i s t i n the c l a s s i f i c a t i o n of the sample p l o t s , f i r s t i nto vegetation groups, and then into commu-n i t y types. Since the c l a s s i f i c a t i o n involved p a r t i t i o n i n g a continuum, as the ordinations v i s u a l l y i l l u s t r a t e , the groups and types may i n t e r -grade and overlap. Thus, i t i s not c l a s s i f i c a t i o n i n a h i e r a r c h i c a l sense, but c l a s s i f i c a t i o n i n the sense of t y p i f i c a t i o n (Noy-Meir and Whittaker, 1978). Vegetation groups are defined as groups of p l o t s that show a general degree of s i m i l a r i t y i n dominant species and environ-mental c h a r a c t e r i s t i c s . Community types are subdivisions of vegetation groups and are defined as assemblages of p l o t s that show a high degree of milarity in-species composition and abundance, as w e l l as i n environmental c h a r a c t e r i s t i c s . Subdivision i n t o groups or types of the l a r g e l y c o n t i -nuous pattern seen i n the ordinations, was done using the following c r i t e r i a i n order of importance : (1) d i s c o n t i n u i t i e s i n the ordination scatter diagrams when present, (2) c a r e f u l inspection of the vegetation data for compositional s i m i l a r i t y , (3) s i m i l a r inspection of the envi-ronmental data. Where boundaries between types were drawn, some sub-j e c t i v i t y was involved as i n any c l a s s i f i c a t i o n . Averages, or noda of the community types are d i s t i n c t v e g e t a t i o n a l l y , and most are also d i s t i n c t environmentally (see canonical analyses). Some p l o t s could not be c l a s s i f i e d and are indicated by s i n g l e dots i n the ordinations. These plot s e i t h e r were unusual compositionally because of edaphic factors or disturbance, or were representative of other, undersampled, communities. Groups and types of communities as defined here do not correspond to any 42 p a r t i c u l a r t r a d i t i o n a l c l a s s i f i c a t i o n system; they are used s o l e l y f o r the purpose of describing useful subdivisions of an otherwise f a i r l y continuous pattern of vegetation v a r i a t i o n . The r e l a t i o n s h i p s between types i s well i l l u s t r a t e d by the ordinations, and some could very well be considered as sub-units or variants of other types. Relationships of types are discussed, but no formal h i e r a r c h i c a l arrangement of types was attempted. The community types are s i m i l a r to dominance-types (Whittaker, 1978) since they are defined p r i m a r i l y on the high s i m i l a r i t y of t h e i r do-minant species. The community types are also s i m i l a r to habitat-types"^, defined by Daubenmire (1968) as the " p o t e n t i a l climax vegetation" of a s i t e . Daubenmire (1968) views the habitat ( s o i l , macroclimate, topo-graphy) as the most durable part of an ecosystem, eventually c o n t r o l -l i n g the f i n a l aspect of the vegetation. Successional or preclimax vegetation can take a more var i e d appearance, on otherwise s i m i l a r s i t e s , due to various disturbances. Tree regeneration and under-story s t r a t a (shrubs, herbs and bryophytes) are most important i n defining habitat-types, since they are established soon; a f t e r d i s -turbance and are l i k e l y to p e r s i s t into the "climax" stage. However, important changes i n understory plants have been demonstrated by Alaback (1982) i n south-east Alaska f o r e s t s during l a t e r successional stages. The use of sapling and seedling data i n the ordinations from which the types were derived allows them to be considered near equivalents of h a b i t a t -types, p a r t i c u l a r l y since most plo t s come from old-growth stands. Habitat-types are usually named by a combination of one, or two, p o t e n t i a l l y dominant species (climax species) as well as an understory dominant 1 Modal community types are also equivalent to ecosystem associations (Klinka et a l . , 1979). 43 (Daubenmire & Daubenmire, 1968). Community types are named informally i n t h i s study according to the dominant tree species and, when necessary for d i f f e r e n t i a t i o n , c h a r a c t e r i s t i c understory species are used. General e c o l o g i c a l and geographical q u a l i f i e r s are sometimes added to the names. Community types were also coded by a l e t t e r to i d e n t i f y the vegetation group and a number to i d e n t i f y the community type. b) Vegetation data summary tables The presentation of one or a few t y p i c a l stands per type does not represent the f u l l range of v a r i a t i o n encountered, while a large number of stands may obscure underlying patterns (Peet, 1981). As an a l t e r n a t i v e , the data from each community type were averaged and constancy values, defined as the percent occurrence of species i n the sample pl o t s of a type, were calculated. In order to keep table length to a minimum, species had to have 50 % constancy, or more, i n at least one of the types represented i n the table to be included (or 100 % when the type had only two p l o t s ) . Of the two Pinus contorta types, one was placed i n the Pseudotsuga group and the other i n the Thuja group tables, according to t h e i r compositional and geographical a f f i n i t i e s . Floodplain types were included i n the tables of the le s s diverse Thuja group. Community data summary tables were divided i n two, with a table for tree, sapling and seedling data f o r each group, and a table for understory data for each group. The tables also include community c h a r a c t e r i s t i c s data, such as mean number of species (species richness or density) and t o t a l number of species f o r trees, shrubs, herbs and bryophytes-lichens. Mean basal area, mean density and mean maximum height are given for trees. Mean 44 t o t a l coverage i s given for shrubs, herbs, bryophytes-lichens and t o t a l understory. Two d i v e r s i t y i n d i c e s , the rec i p r o c a l . o f Simpson's Index (dominance concentration) and the a n t i l o g of the Shannon-Weaver Index ( e q u i t a b i l i t y ) ( P e e t , 1974), were calculated for the trees (> 10 cm DBH), the understory vascular plants (shrubs and herbs), and for the bryophytes and lichens. Within the Pseudotsuga group tables the types were arranged,, from l e f t to r i g h t , i n order of increasing s o i l moisture (except P7 which i s d r i e r than P6) and increasing elevation (eg. P3 i s d r i e r than P2 but occurs at higher e l e v a t i o n s ) . The Thuja group tables were arranged i n order of increasing s o i l moisture and decreasing drainage (except the F l type which i s moderately well drained). The Abies group tables were organized i n order of increasing s o i l moisture, f o r high elevation types up to type A4, and i n order of decreasing s o i l moisture f o r low elevation types (A5 to A7). 45 3. CANONICAL ANALYSES OF COMMUNITY TYPES AND VEGETATION GROUPS BASED  ON ENVIRONMENTAL DATA Canonical va r i a t e s analysis was used to examine r e l a t i o n s h i p s among the vegetation groups and community types, delineated i n the o r d i -nations, on the basis of the environmental data. The environmental va r i a b l e s used are l i s t e d i n Table 1 (distance from the coast, a geo-graphical v a r i a b l e , was not used, as well as pH for A and B 2 horizons, which were missing from numerous s o i l p r o f i l e s ) . Canonical analysis accentuates differences among preestablished groups (Seal, 1964), and was used to assess the degree of environmental s i m i l a r i t y among what are considered to be v e g e t a t i o n a l l y d i s t i n c t u n i t s . Separate canonical analyses were run for the s i x vegetation groups, a l l community types, and the community types within each of the Pseudotsuga, Thuja and Abies groups. To show the r e s u l t s g r a p h i c a l l y , the means of plots belonging to groups or types were plotted along the f i r s t two canonical v a r i a t e axes for each analysis (Figs. 13 and 14). Seal's (1964) method was used to calculate 90 % confidence c i r c l e s around the means (radius = 1.645 v/"n) . The s i z e of the confidence c i r c l e s i s linked to sample s i z e ; groups or types con s i s t i n g of few p l o t s w i l l have large confidence c i r c l e s . The generalized distance measure of Mahalanobis (Mahalanobis squared distance, D 2) was used to measure the distance between the type centroids i n the environmental space (Goodall, 1978; O r l d c i , 1972). As i s the case with most e c o l o g i c a l data, the assumptions necessary for the s t a t i s t i c a l i n t e r -pretation of canonical analysis are v i o l a t e d , therefore the technique becomes a data-exploratory procedure to provide useful i n s i g h t s (Williams, 1983). 46 Stepwise forward discriminant analysis also was used to analyse environmental r e l a t i o n s h i p s among the groups and types. This method selec t s environmental v a r i a b l e s which best discriminate among the vege-ta t i o n u n i t s , and also reassigns the i n d i v i d u a l plots to units where they share the greatest o v e r a l l environmental s i m i l a r i t y . Thus, the method provided a means to test the vegetation c l a s s i f i c a t i o n using an independent set of environmental v a r i a b l e s . The separation of vegetation groups and community types obtained by discriminant analysis was s i m i l a r to those produced by canonical a n a l y s i s ; therefore, only the l a t t e r r e s u l t s are discussed i n d e t a i l . The tabular r e s u l t s from discriminant analysis are presented i n Appendix 4. Canonical and discriminant ana-l y s i s were performed using programs from the MIDAS s t a t i s t i c a l package supported by the University of B r i t i s h Columbia Computing Centre. 47 4. VEGETATION STRATA HOMOGENEITY WITHIN TYPES As a measure of the homogeneity of the vegetation strata within different community types, interplot similarity matrices were calculated using the data from each stratum for individual community types. The mean interplot similarities would indicate the relative homogeneity of the vegetation within each community type, as well as the variations in homogeneity between vegetation strata (Bradfield and Scagel, 1984). The similarity between plots was defined by the cosine function. The value of this function ranges from 0.0, for plots with no species in common, to 1.0, for plots with the same species occurring in identical proportions (Bradfield and Scagel, 1984). The homogeneity of the tree, sapling, seedling, shrub, herb arid bryophyte-lichen strata of fourteen community types was compared using this measure (Table 31). Community types with less than five plots were not included in this analysis, except for the two Pinus contorta community types, which otherwise would have l e f t that group unrepresented, and the coastal wet Thuja forests (T5, 4 plots), which appeared unusually homo-geneous . 48 5. TREE SIZE-CLASS STRUCTURE OF COMMUNITY TYPES Graphs showing the s i z e - c l a s s d i s t r i b u t i o n s of tree species within community types were plotted to provide descriptions of community structure, and to a s s i s t i n the i n t e r p r e t a t i o n of community dynamics. Community types with less than three p l o t s were not analysed. The f l o o d -p l a i n forests (Fl) community type also was not analysed because of the great heterogeneity of i t s tree stratum. The data used are the number of stems of tree species i n 10 cm DBH si z e - c l a s s e s for a l l pl o t s of each community type. These data were transformed into numbers of stems per s i z e - c l a s s per hectare (one pl o t - .05 ha). The number of tree seedlings per hectare also was calculated using density data obtained from the microplots (twenty 1 m2 microplots per p l o t ) . Graphs of tree species stem density per hectare versus s i z e - c l a s s were made, using a logarithmic scale for stem density. Hand-fitted and smoothed curves were drawn for the tree species with the highest impor-tance values within the selected community types (Figs. 15, 16 and 17). 49 6. TREE SEEDLING ABUNDANCE ON UNDECOMPOSED WOOD AND FOREST FLOOR SUBSTRATA The tree seedling density data were analysed to determine whether there was a s i g n i f i c a n t d i f f e r e n c e between average seedling d e n s i t i e s on two broad types of substrata. During the sampling,microplots were re -corded as being located on forest f l o o r (including mineral s o i l , humus or l i t t e r ) or on undecomposed wood ( f a l l e n trees, tree stumps, debris and bark at tree bases). Only the data from pl o t s sampled using a random design of microplot l o c a t i o n (Fig. 4) were u t i l i s e d i n the s t a t i s t i c a l t e s t . To be included,tree species had to be present as seedlings i n at least f i f t y percent of the plots (500 m 2), but not n e c e s s a r i l y i n 50 % of the microplots within each p l o t . The mean number of tree seedlings per square metre for each species, on each of the two substratum types, was calculated for community types with s u f f i c i e n t data (at least one hundred randomly selected microplots). The n u l l hypothesis i s that tree seedling abundance, of each spe-c i e s , i s equal on both, substratum types. The two sample z-test was used to make the comparisons (Freedman et a l . , 1978). Compared to the more f a m i l i a r t - t e s t , the z-test provides a good approximation of the true value of P even when the data do not follow the normal curve very w e l l , provided the sample s i z e i s large enough for the normal approximation to take over. The t - t e s t requires that the data follow the normal curve c l o s e l y (Freedman et a l . , 1978). 50 CHAPTER 4. RESULTS A. GRADIENT ANALYSIS OF VEGETATION 1. GENERAL VEGETATION PATTERNS a) 172_plots_ordination The r e c i p r o c a l averaging ordination of the 172 sample plo t s shows a mass of c e n t r a l l y located p l o t s surrounded by groups of o u t l i e r p l o t s (Fig. 5). The data matrix f o r t h i s ordination consisted of 172 plo t s and a t o t a l of 197 species, or pseudo-species f o r trees divided into s i z e - c l a s s e s . Species, or pseudo-species, included i n the matrix were present i n at least four p l o t s (14 trees, 11 saplings, 11 seedlings, 24 shrubs, 81 herbs, 56 bryophytes and l i c h e n s ) . The f i r s t and second axes explained 11.0 % and 8.8 %, re s p e c t i v e l y , of the t o t a l variance. Correlations of environmental v a r i a b l e s with the ordination axes are given i n Table 4. The strongest c o r r e l a t i o n with the f i r s t axis i s with e f f e c t i v e rooting depth/soil depth r a t i o , i n d i c a t i n g f u l l e r u t i l i z a t i o n by tree roots of a decreasing s o i l layer i n plots located towards the p o s i t i v e end of the axis. Pinus contorta has the largest p o s i t i v e eigen-vector c o e f f i c i e n t on the f i r s t axis (Table 3), and i s the dominant tree species i n a group of shallow s o i l , rock outcrop communities i d e n t i f i e d at the extreme r i g h t of the ordination (Fig. 5). Two community types, a dry Pinus-Pseudotsuga type (Dl) and a coastal dry Pinus type (D2), were recognized within t h i s group by compositional and geographical 51 differences. Other environmental c o r r e l a t i o n s with the Pinus types are i n c r e a s i n g l y better drainage, decreasing s o i l depth, coarser s o i l mate-r i a l , increasing percent rock fragments, thinner organic layer, increasing f i r e disturbance, and ridge topographical p o s i t i o n (Table 4). The two other groups i d e n t i f i e d on t h i s ordination are separated along the second axis. Elevation i s the environmental v a r i a b l e most strongly correlated with the second axis (Table 4). A d i s t i n c t group of subalpine p l o t s characterised by Abies amabilis (saplings, trees, seed-lings) , Vaccinium alaskaense, Rhytidiopsis robusta and Tsuga mertensiana i s i d e n t i f i e d at the top l e f t of the ordination (Table 3). Picea s i t c h e n s i s (trees, seedlings), Rubus s p e c t a b i l i s , Ribes  bracteosum and Polystichum muniturn have the largest negative eigenvector c o e f f i c i e n t s on the second axis (Table 3). These species are characte-r i s t i c of a group of f l o o d p l a i n and r i v e r terrace p l o t s i d e n t i f i e d toward the bottom of the ordination. Correlated with the lower elevation f l o o d -p l a i n p l o t s are an increase i n organic layer pH, lower topographical p o s i t i o n ( l e v e l ) , f i n e r s o i l material ( a l l u v i a l ) , an increase i n B^ horizon pH (richer s o i l ) , deeper rooting, and increasing tree t o t a l basal area and maximum height (both i n d i r e c t i n d i c a t i o n s of s i t e p r o d u c t i v i t y ) (Table 4). Two community types, subsequently referred to as F l and F2, were i d e n t i f i e d within the f l o o d p l a i n group based on compositional and q u a l i t y of drainage di f f e r e n c e s . A f i n a l community type, termed the dry Pseudotsuga forests (PI), was recognized toward the lower r i g h t of the ordination. This type con-s i s t s of four p l o t s that share a strong dominance by Pseudotsuga menziesii, 52 contain Arbutus menziesii, but lack Pinus contorta. Gaultheria shallon strongly dominates the shrub layer. Although not d i s t i n c t i v e i n the ordination, because of compositional s i m i l a r i t i e s to several other plots dominated by Pseudotsuga menziesii, these s i t e s have i n common s i m i l a r s o i l c h a r a c t e r i s t i c s and recent f i r e h i s t o r i e s . b) J?i2££_££dination Following the removal of p l o t s assigned to community types i n the f i r s t ordination, a second r e c i p r o c a l averaging ordination was run on the remaining 140 p l o t s (Fig. 6). The data matrix for t h i s ordination con-s i s t e d of 140 plots and 149 species (or pseudo-species for trees divided i n t o s i z e - c l a s s e s ) . Species included were present i n at least four p l o t s (12 trees, 7 saplings, 10 seedlings, 20 shrubs, 62 herbs, 38 bryophytes and l i c h e n s ) . The f i r s t and second axes explained 13.6 % and 9.8 %, r e s p e c t i v e l y , of the t o t a l variance. In general, the main vegetation patterns on the f i r s t two axes appear to be determined by the i n t e r a c t i o n of complex environmental gradients associated with distance from the coast and elevation. F i r e disturbance has the strongest p o s i t i v e corre-l a t i o n with the f i r s t axis (Table 6), while Pseudotsuga menziesii trees and seedlings have the largest p o s i t i v e eigenvector c o e f f i c i e n t s on t h i s axis (Table 5). Distance from the coast has the strongest c o r r e l a t i o n with the second axis, decreasing toward the p o s i t i v e pole (Table 6), where Gaultheria shallon, Thuja p l i c a t a (seedlings, trees, s a p l i n g s ) , Vaccinium  ovatum and Blechnum spicant increase i n coverage (Table 5). Abies amabilis (trees, saplings, seedlings) has the strongest negative eigenvector coef-f i c i e n t s on both the f i r s t and second axes (Table 5). This tends to p u l l p l o t s where i t dominates, and regenerates i t s e l f , toward the lower l e f t of 53 the ordination. Based on these r e s u l t s and a f t e r c a r e f u l consideration of the vegetation and environmental data, the 140 plots were subdivided into three broadly defined groups : a Pseudotsuga group at the lower r i g h t , a Thuja group at the top, and an Abies group at the lower l e f t . Along the f i r s t axis, c o r r e l a t i o n s with several e c o l o g i c a l v a r i a b l e s help to d i f f e r e n t i a t e the Pseudotsuga group from the others, such as : increasing evidence of f i r e disturbance, better drainage, thinner organic layer, deeper rooting, deeper rooting i n mineral s o i l , increasing distant-ce from the coast (inland), and decreasing evidence of wind disturbance (Table 6). S i m i l a r l y , on the second axis, c o r r e l a t i o n s with several eco-l o g i c a l v a r i a b l e s help to d i f f e r e n t i a t e the Thuja group from the two others, such as : geographical proximity to the coast, increasing e v i -dence of wind disturbance, decreasing elevation (nearer to sea l e v e l ) , decreasing tree height and drainage, and decreasing evidence of f i r e disturbance (Table 6). General c h a r a c t e r i s t i c s of the Abies group plots include a tendency to occupy higher elevations, where there i s l i t t l e evidence of disturbance by f i r e or wind, and having no d e f i n i t e geogra-p h i c a l area of maximum occurrence. An aberrant plot with a recent f i r e -h i s t o r y , situated inland near Port A l b e r n i , and dominated by scattered large _P. menziesii which survived the f i r e , was not assigned to any of the groups (small dot on F i g . 6). The dominance i n the understory by a dense cover of Vaccinium ovatum, a shrub most commonly associated with open coastal habitats on poor s o i l s , i s probably responsible for the p o s i t i o n i n g of t h i s p l o t closer to the Thuja group i n the ordination. 54 2. VEGETATION PATTERNS WITHIN THE PSEUDOTSUGA GROUP The data matrix for the ordination of t h i s group consisted of 59 p l o t s and 119 species (or pseudo-species for t r e e s ) . Species included were present i n at least three p l o t s (9 trees, 7 saplings, 9 seedlings, 17 shrubs, 51 herbs, 26 bryophytes and l i c h e n s ) . The f i r s t and second axes explained 14.4 % and 9.6 %, r e s p e c t i v e l y , of the t o t a l variance. The ordination of the plots from the Pseudotsuga group reveals a more det a i l e d pattern within t h i s group (Fig. 7a). The f i r s t ordination axis i s best correlated with organic layer pH and vascular species richness (Table 8). This r e s u l t s i n a separation of species r i c h p l o t s , with Acer macrophyllum present, at the negative end of the axis, from species poor plots at the p o s i t i v e end, where Tsuga heterophylla (seedlings, saplings, trees), Blechnum spicant, and Polystichum munitum are important. Acer macrophyllum (saplings, seedlings), Cornus n u t t a l l i i (seedlings, saplings, trees) and P_. menziesii (seedlings, saplings) have the largest negative eigenvector c o e f f i c i e n t s on the f i r s t axis (Table 7) helping to d i f f e r e n t i a t e the Pseudotsuga-Thuj a-Acer f o r e s t s community type (P2). This i s the most f l o r i s t i c a l l y r i c h of the Pseudotsuga types and has the l e a s t a c i d i c organic layer, probably because of the l i t t e r input from the deciduous trees present. Other c h a r a c t e r i s t i c s of t h i s community type are a greater understory coverage, furthest distance from the coast ( a l l p lots situated very near Port A l b e r n i ) , shallower s o i l s and thinner organic layer (Table 8). Variables strongly correlated with the second axis are t o t a l shrub coverage and topographical p o s i t i o n (Table 8). Plots near the negative 55 end of the second axis tend to occur i n higher topographical pos i t i o n s (ridges, c r e s t s , upper slopes), while pl o t s at the p o s i t i v e end tend tb occur i n lower topographical pos i t i o n s (mid-slopes and lower-slopes). This pattern i s also evident i n the d i r e c t ordination of the Pseudotsuga group (Fig. 7 b ) . For the second axis, a gradient of increasing s i t e p r o d u c t i v i t y , although not d i r e c t l y measured, can be i n f e r r e d also from several variables such as : decreasing t o t a l shrub coverage and t o t a l understory coverage (because of closing canopy), increasing t o t a l tree basal area and maximum tree height, increasing percent nitrogen i n B2 horizons, and decreasing C/N r a t i o s i n Bj horizons (Table 8 ) . The Tsuga- Pseudotsuga-Polystichum forests community type (P5) occupies the most productive end of t h i s gradient, as w e l l as lower-slopes (Fig. 7a and 7 b ) . The l e a s t productive end of the gradient i s occupied by two community types, the Pseudotsuga-Linnaea f o r e s t s (P3) and the montane Tsuga- Gaultheria forests (P7) (Fig. 7 a ) . F l o r i s t i c differences separate these two types c l e a r l y on the r e c i p r o c a l averaging ordination (Fig. 7 a ) . Ecolo-g i c a l l y , the two types are d i f f e r e n t i a t e d by elevation, with the montane Tsuga-Gaultheria forests occurring.at higher elevations (Fig. 7 b ) . Two other community types are of intermediate p o s i t i o n on the second axis, the Pseudotsuga-Berberis forests (P4) and the montane Tsuga forests ( P 6 ). These two types are distinguishable f l o r i s t i c a l l y , but intergrade more or le s s continuously along the e l e v a t i o n a l gradient (Figs. 7a and 7 b ) . On the second a x i s , Gaultheria shallon and Hylocomium  splendens have the largest negative eigenvector c o e f f i c i e n t s , corresponding to the poorer and d r i e r s i t e s (Fig. 7 a ), while Polystichum muniturn and Cornus n u t t a l l i i have the largest p o s i t i v e eigenvector c o e f f i c i e n t s , 56 corresponding to the r i c h e r and moister s i t e s (Figs 7a and 7b; Table 7). A gradient of increasing s o i l moisture a v a i l a b i l i t y also can be suggested for the second axis based on r e l a t i o n s h i p s indicated i n the d i r e c t o r d i -nation (Fig. 7b). The montane Tsuga-Gaultheria forests community type i s situated at the dry end of t h i s gradient on ridges and south-southwest facing slopes, and the Tsuga-Pseudotsuga-Poly.stichum forests community type i s situated at the moist end on lower-slopes, with more seepage, deeper s o i l s and better shelter from drying winds. Communities, of i n t e r -mediate p o s i t i o n on the topographic-moisture gradient of F i g . 7b are also intermediate i n p o s i t i o n on the second axis of F i g . 7a. The dry Pinus-Pseudotsuga forests (Dl) were added to fig u r e 7b to show t h e i r topogra-p h i c a l p o s i t i o n s . Three unique pl o t s were not assigned to any community type within t h i s group. Plot 112 i s from the China Creek area, west of Port A l b e r n i , and has a d r i e r climate and a s o i l d i f f e r e n t from that commonly found within the study area. Plot 89 i s from an unusual co a s t a l stand dominated by Thuja p l i c a t a , but with a high cover of Polystichum  munitum which caused t h i s p l o t to be included with the Pseudotsuga group. Plot 20 represents a r e l a t i v e l y recently disturbed s i t e . 57 3. VEGETATION PATTERNS WITHIN THE THUJA GROUP The data matrix for the ordination of t h i s group consisted of 40 p l o t s and 25 species (or pseudo-species for t r e e s ) . Species included were present i n at least three p l o t s (7 trees, 4 saplings, 6 seedlings, 9 shrubs, 22 herbs and 27 bryophytes). The f i r s t and second axes ex-plained 23.4 % and 13.5 %, r e s p e c t i v e l y , of the t o t a l variance. Five community types were i d e n t i f i e d within the Thuja group ordination (Fig. 8a). Based on c o r r e l a t i o n s with e c o l o g i c a l v a r i a b l e s the f i r s t axis i s i n t e r -preted as a s i t e p r o d u c t i v i t y gradient. The strongest c o r r e l a t i o n s with the f i r s t axis are with t o t a l shrub coverage, t o t a l understory coverage and maximum tree height (Table 10). Other v a r i a b l e s correlated with the f i r s t axis are also i n d i c a t o r s of s i t e p r o d u c t i v i t y , such as increasing s o i l depth, organic layer percent nitrogen, decreasing organic layer C/N r a t i o , increasing percent nitrogen and carbon i n Bj horizons, and i n c r e a -sing root r e s t r i c t i n g depth (Table 10). Abies amabilis (saplings, trees, seedlings), Tsuga heterophylla (seedlings, saplings) and Polystichum muniturn have the largest p o s i t i v e eigenvector c o e f f i c i e n t s on the f i r s t axis (Table 9), and characterize a group of productive s i t e s at the r i g h t of the ordination; Vaccinium ovatum and Thuja p l i c a t a (saplings, seedlings) have the largest negative eigenvector c o e f f i c i e n t s and characterize the l e s s productive s i t e s to the l e f t . The coastal Tsuga-Blechnum-Polystichum forests community type (T2) i s considered to be the most productive of t h i s group. This community type occurs on upper and mid-slopes only, mostly above 200 m of elevation (Fig. 8b), where there i s better drainage and l e s s coastal fog influence than at lower elevations. The l a s t two factors seem to greatly influence p r o d u c t i v i t y i n coastal forests where moisture i s often overabundant. The coastal dry Thuja forests (TI) and 58 the co a s t a l wet Thuja forests (T5) community types are both considered to occur on the most unproductive s i t e s of t h i s group. The dry type i s found on well drained ridges and steep slopes, while the wet type occurs on poorly drained l e v e l s i t e s ( F ig. 8b). In both cases Vaccinium ovatum dominates the shrub layer, accounting for t h e i r close positions on the r e c i p r o c a l averaging ordination (Fig. 8a). Environmental gradients underlying the second axis are not as cle a r . Herb species richness and t o t a l herb coverage are strongly corref-lated with the second axis (Table 10), mostly because of plo t 85, a unique sample pl o t from a r i c h f e n - l i k e coastal Thuja swamp on poorly drained marine clays. The presence of plo t 85 (nearly at sea le v e l ) also weakens the c o r r e l a t i o n of the second axis with e l e v a t i o n , which otherwise can be seen on the d i r e c t ordination (Fig. 8b). The coastal montane Thuja forests community type (T3), intergrades continuously with the coastal Thuja forests community type (T4) along the elevation gradient (Fig. 8b) although f l o r i s t i c differences (such as higher importance of Abies amabilis i n the T3 type), help to separate them i n the i n d i r e c t ordination ( Fig. 8a). The coastal Thuja f o r e s t s form the most common and c h a r a c t e r i s t i c commu-n i t y type of the lowland coastal f o r e s t s of western Vancouver Island. 59 4. VEGETATION PATTERNS WITHIN THE ABIES GROUP The data matrix for the ordination of t h i s group consisted of 40 plo t s and 87 species (or pseudo-species for t r e e s ) . Species included were present i n at l e a s t three p l o t s (5 trees, 4 saplings, 5 seedlings, 9 shrubs, 36 herbs, 28 bryophytes and l i c h e n s ) . The f i r s t , second and t h i r d axes explained 16.7 %, 10.9 % and 10.3 %, r e s p e c t i v e l y , of the t o t a l variance. The r e c i p r o c a l averaging ordination of the Abies group i s the only case i n t h i s study where i t was f e l t that the t h i r d axis offered clearer r e l a t i o n s h i p s , patterns, and environmental gradient i n t e r p r e t a t i o n s than the second axis (Fig. 9a). The occasional advan-tage, f o r i n t e r p r e t a t i o n purposes, of using the t h i r d r e c i p r o c a l averaging axis instead of the second has been noted also by Gauch, et a l . (1977) and Peet (1980). Species with the largest p o s i t i v e eigenvector c o e f f i c i e n t s on the f i r s t axis are Tsuga heterophylla (saplings, seedlings, t r e e s ) , Pseudotsuga menziesii (trees) and Polystichum muniturn, while species with the largest negative eigenvector c o e f f i c i e n t s are Abies amabilis (saplings, seedlings, t r e e s ) , Rubus pedatus and Streptopus streptopoides (Table 11). C l e a r l y , the f i r s t axis separates p l o t s where tree species regeneration i s dominated by e i t h e r Abies amabilis or Tsuga heterophylla. Correlation of environmental v a r i a b l e s with the f i r s t axis indicate that the p l o t s where Abies regeneration dominates are the furthest from the coast and the highest i n elevation (geographically where the highest mountains are found). Percent carbon i n the organic layer i s highest i n these p l o t s while pH of the B^ horizon i s lowest (Table 12). At the extremities of the f i r s t a x is, two d i s t i n c t community types can be iden-t i f i e d , the montane Abies-Streptopus forests (A4), of high elevation, 60 cool north to north-west facing slopes, and the Tsuga-Blechnum-Polystichum forests (A7), of low elevation mesic s i t e s (Figs. 9a and 9b). The t h i r d axis i s interpreted as a complex environmental gradient associated with increasing elevation, exposure and f i r e disturbance, and decreasing p r o d u c t i v i t y i n f e r r e d from an increase i n organic layer C/N r a t i o and a decrease i n tree height (Table 12). On the t h i r d a xis, Gaultheria  shallon, Abies amabilis (seedlings, s a p l i n g s ) , Rhytidiopsis robusta and Pseudotsuga menziesii have the largest p o s i t i v e eigenvector c o e f f i c i e n t s . These species characterize the f i r e prone, most nutrient poor and d r i e r s i t e s within the Abies group. Sphagnum girgensohnii, Abies amabilis ( t r e e ) , Achlys t r i p h y l l a and Polystichum muniturn have the largest nega-t i v e eigenvector c o e f f i c i e n t s on the t h i r d a xis, and characterize the mesic, most nutrient r i c h s i t e s (Table 12). The montane Tsuga-Abies- Gaultheria forests community type (Al) occurs inland from mid to high elevations on dry slopes where there i s v i s i b l e evidence of f i r e ( F ig. 9b). The opposite end of t h i s gradient i s occupied by the lowland Abies forests (A5) and the montane Tsuga-Abies f o r e s t s (A3). The lowland Abies forests occur at low elevations i n v a l l e y bottoms but bear close f l o r i s t i c resemblance to the e l e v a t i o n a l l y and topographically d i f f e r e n t montane Abies-Streptopus forests (Figs. 9a and 9b), montane Tsuga-Abies f o r e s t s (A3) occur on higher well drained slopes near the coast (Fig. 9a). Other community types are, the montane Abies-Tsuga forests (A2), which occur on high elevation s i t e s with a better drainage than found i n s i t e s occupied by the montane Abies-Streptopus forests (A4), and the Tsuga- Gaultheria-Blechnum forests (A6), which occupy possibly l e s s productive s i t e s than the Tsuga-Blechnum-Polystichum forests (A7)(Fig. 9a). Eight 61 pl o t s were not assigned to any of the types within t h i s group. Plots 28, 83, 127 and 168 are strongly influenced by seepage water, making t h e i r r e l a t i o n s h i p s d i f f i c u l t to evaluate through vegetation data. Plot 151 i s a r e l a t i v e l y young stand, r e s u l t i n g from a complete blow-down, sampled for comparison purposes. Plot 113 i s from a high elevation stand i n the d r i e r China Creek area (see Pseudotsuga group). Plot 35 i s from a high elevation s i t e (865 m), but lacks the c h a r a c t e r i s t i c species which would have placed i t within the subalpine group of F i g . 5. Plot 68 i s a p a r t i a l l y wind disturbed stand most s i m i l a r to the montane Tsuga-Abies f o r e s t s . 62 5. VEGETATION AND ENVIRONMENTAL PATTERNS ON A DISTANCE FROM THE COAST  GRADIENT The data matrix for the ordination of t h i s group of modal p l o t s consisted of 105 p l o t s and 147 species (or pseudo-species for t r e e s ) . Species included were present i n at least 4 p l o t s (11 trees, 7 saplings, 10 seedlings, 20 shrubs, 61 herbs, 38 bryophytes). The f i r s t and second axes of a r e c i p r o c a l averaging ordination explained 15.0 % and 8.8 %, r e s p e c t i v e l y , of the t o t a l variance, and produced a strongly arched scat-ter of p l o t s (Fig. 10). Species with the largest p o s i t i v e eigenvector c o e f f i c i e n t s on the f i r s t axis are Pseudotsuga menziesii (trees, seedlings), Acer macrophyllum (saplings, seedlings) and Cornus n u t t a l l i i (saplings, seedlings), while species with the la r g e s t negative eigenvector c o e f f i -cients are Blechnum spicant, Abies amabilis (saplings, trees, seedlings) and Thuja p l i c a t a (trees) (Table 13). The f i r s t axis separates pl o t s of the Thuja group from p l o t s of the Pseudotsuga group. This i s s i m i l a r to the separation on the f i r s t axis of the 140 plots ordination (Fig. 6), except that, i n t h i s case, most plo t s of the Abies group have been removed. The few p l o t s belonging to the Abies group are c e n t r a l l y located on the 105 modal plo t s ordination. Correlation of environmental variables with the f i r s t axis c l e a r l y demonstrates the strong e f f e c t that distance from the coast has on vegetation v a r i a t i o n i n the study area. This geo-graphical gradient summarizes the e f f e c t s of many separate environmental variables including f i r e and wind disturbance, organic horizons thickness/ e f f e c t i v e rooting depth r a t i o , drainage and organic horizons thickness (Table 14). However, i t must be recognized that organic horizons t h i c k -ness and e f f e c t i v e rooting depth are p a r t i a l l y a function of the overlying 63 vegetation. The increasing p r e c i p i t a t i o n and decreasing growing degree-days towards the coast can be seen on i s o l i n e maps adapted from climate maps compiled by Colidago (1980) (Fig. 12). Also, the organic horizons t h i c k n e s s / e f f e c t i v e rooting depth r a t i o decreases and vascular species richness increases with increasing distance from the coast (Fig. 12). Correlations of environmental v a r i a b l e s with the second axis show re l a t i o n s h i p s s i m i l a r to those shown on the f i r s t axis (Table 14). Polynomial regression curves of the basal area of major tree species show d i s t i n c t peaks along the distance from the coast gradient (Fig. 11) Thuja p l i c a t a reaches a peak i n t o t a l basal area 13 km from the coast, while Pseudotsuga menziesii reaches i t s peak at about 48 km from the coast. Tsuga heterophylla reaches i t s peak i n basal area at 30 km from the coast. The basal area of Abies amabilis increases s t e a d i l y towards the coast. Thuja p l i c a t a shows a marked decrease i n basal area when closer than 10 km from the coast. A s i m i l a r decrease i n Tsuga hetero- p h y l l a basal area occurs at about 50 km from the coast (Fig. 11). The organic horizons t h i c k n e s s / e f f e c t i v e rooting depth r a t i o polynomial regression curve also shows a d i s t i n c t dip towards the inland part of the i s l a n d (Fig. 11). The peaks and decreases i n basal area of each tree species can be interpreted as responses to c l i m a t i c v a r i a b l e s and disturbance type and regime, which are linked with climate. The v a r i a -tions i n the organic horizons t h i c k n e s s / e f f e c t i v e rooting depth r a t i o can be interpreted as the r e s u l t of climate and vegetation d i f f e r e n c e s . A l l these r e l a t i o n s h i p s are discussed further i n chapter 5. 64 B. CANONICAL ANALYSES OF VEGETATION GROUPS AND COMMUNITY TYPES BASED ON ENVIRONMENTAL DATA 1. VEGETATION GROUPS The s i x vegetation group centroids are separated c l e a r l y on the f i r s t and second canonical v a r i a t e s of the environmental data (Fig. 13). These two axes summarize the main environmental r e l a t i o n s h i p s among the s i x vegetation groups. The Pinus contorta group (D) and the Floodplain group (F) are at opposite ends of the f i r s t two canonical v a r i a t e s . This large d i f f e r e n c e i n environmental c h a r a c t e r i s t i c s also i s r e f l e c t e d i n the Mahalanobis squared distance (D 2) between these two groups (Table 16). Drainage, s u r f i c i a l m aterial, topographic p o s i t i o n and coarse fragment content of the Bj horizon are the environmental variables most strongly correlated with the f i r s t canonical v a r i a t e (Table 21). F i r e and wind disturbance are also c o r r e l a t e d , p o s i t i v e l y and negatively, r e s p e c t i v e l y , with the f i r s t axis. The r a t i o , organic horizons t h i c k n e s s / e f f e c t i v e rooting depth, and organic horizons thickness are negatively correlated with the second canonical v a r i a t e , while organic horizons pH i s p o s i t i v e l y correlated (Table 21). Very rapid drainage, crest or ridge topographic p o s i t i o n , and lack of s u r f i c i a l material (rock outcrops) characterize the Pinus contorta group (D). Slower drainage, lower-slope or l e v e l topo-graphic p o s i t i o n s , and morainal, f l u v i a l or a l l u v i a l s u r f i c i a l deposits characterize the Floodplain (F) and Thuja (T) groups. Group positions on the second canonical v a r i a t e can be best interpreted with the organic horizons t h i c k n e s s / e f f e c t i v e rooting depth r a t i o ; the Floodplain group 65 i s characterized by th i n organic horizons and deep rooting into mineral s o i l ( r a t i o closer to zero), while the Thuja group i s characterized by thick organic horizons and shallow rooting ( r a t i o closer to one). Although organic horizons are t h i n i n the Pinus contorta group, the rooting i s very shallow. The Pseudotsuga group (P) i s the group with the higher environmental s i m i l a r i t y with the Pinus contorta group, based on D 2 values (Table 16). The Abies group (A), having several pl o t s situated at high elevations, i s the group most environmentally s i m i l a r to the Subalpine group (SA) based on D 2 values. I t should be noted that the D 2 values are calculated over a l l the dimensions of the canonical analysis while only two dimensions are presented i n the figures (Figs. 13 and 14). Comparing only the Pseudotsuga, Thuj a and Abies groups, we f i n d that the Pseudotsuga and Thuja groups are the most environmentally d i f f e r e n t (Table 16). The canonical analysis r e s u l t s correspond generally to those obtained with r e c i p r o c a l averaging (Figs. 5, 6 and 13). The c o r r e l a t i o n s of environmental v a r i a b l e s with the r e c i p r o c a l averaging axes also are s i m i l a r to those with the canonical v a r i a t e axes (Tables 4, 6 and 21). That the r e s u l t s of both analyses conform i s i n t e r e s t i n g since the r e c i -p rocal averaging ordinations used vegetation data, and the canonical analysis used environmental data. However, the groups submitted to the canonical analysis were determined using r e c i p r o c a l averaging ordinations. The r e s u l t s do indi c a t e that environmental patterns correspond to the vegetation patterns. 66 2. PSEUDOTSUGA TYPES Most of the Pseudotsuga type centroids are separated c l e a r l y on the f i r s t two canonical v a r i a t e s ( Fig. 13). The dry Pseudotsuga forests (PI), the Pseudotsuga-Thuja-Acer forests (P2), and the Pseudotsuga- Linnaea forests (P3) appear very s i m i l a r environmentally (Fig. 13; Table 17). Plots belonging to these three community types are found only i n the d r i e s t inland part of the study area. The dry Pseudotsuga forests (PI) can be separated from the P2 and P3 types (other two commu-n i t y types) on the basis of i t s vegetation structure, which i s hypothe-sized to have resulted from a recent, intense f i r e (see Chapter 4. A, section l a , and 4. C, section 2). S i m i l a r l y , the Pseudotsuga-Thuja-Acer forests (P2) show vegetation differences with PI and P3 which are i n t e r -preted to r e f l e c t differences i n seepage conditions (Chapter 4.C, section 2). Since none of the environmental variables included i n the canonical analysis adequately r e f l e c t e d the underlying reasons for the vegetation dif f e r e n c e s , the three types (PI, P2, P3) were not separated. The Pseudo- tsuga-Thuja-Acer forests (P2) and the Tsuga-Pseudotsuga-Polystichum forests (P5) are at opposite ends of the f i r s t canonical axis. These are the most environmentally d i f f e r e n t types within the Pseudotsuga group (Fig. 13, Table 17). The two most environmentally s i m i l a r community types are the Pseudotsuga-Berberis f o r e s t s (P4) and the montane Tsuga forests (P6) which are d i f f e r e n t i a t e d v e g e t a t i o n a l l y only along an e l e -vation gradient (Fig. 7a and b). The Pseudotsuga-Linnaea forests (P3) and the montane Tsuga-Gaultheria f o r e s t s (P7) , both occurring i n dry s i t e s , show vegetation s i m i l a r i t i e s ( f i g . 7a) but are environmentally 67 quite d i f f e r e n t (Figs. 7b a n d l l 3 ) , mostly because of differences i n elevation. Topographic p o s i t i o n , s o i l depth, e f f e c t i v e rooting depth/ s o i l depth r a t i o , and organic horizons pH are the environmental v a r i a b l e s most strongly correlated with the f i r s t canonical axis (Table 21). The Thuja-Pseudotsuga-Polystichum f o r e s t s (P5) , with the largest scores on the f i r s t a x is, always are found on the lower topographical p o s i t i o n s and on the deepest s o i l s . Elevation, organic horizons pH, horizon % nitrogen, and topographic p o s i t i o n are strongly correlated with the second canonical axis. Montane Tsuga-Gaultheria forests (P7), located toward the top of the second a x i s , are found at high elevations on ridges and c r e s t s . The Pseudotsuga-Thuja-Acer forests (P2), near the bottom of the second axis, have the highest organic horizons pH. A l l of these environmental v a r i a b l e s also were correlated with the r e c i p r o c a l averaging ordination axes of the vegetation data (Fig. 7a; Table 8). 68 3. THUJA TYPES The Thuja type centroids are very c l e a r l y separated on the f i r s t two canonical v a r i a t e s of the environmental data (Fig. 13). The c o a s t a l Tsuga-Blechnum-Polystichum forests (T2) and the coastal montane Thuja forests (T3) are at opposite ends of the f i r s t axis. These two types appear to be the most environmentally d i f f e r e n t within the Thuja group (Fig. 13; Table 18). The coastal Thuja forests (T4) and the coastal wet Thuj a forests (T5) have the most s i m i l a r environmental c h a r a c t e r i s t i c s based on the D 2 values (Table 18). The coastal dry Thuja forests (Tl) could not be included i n the analysis because most of the stands lacked mineral s o i l , and therefore lacked values for numerous environmental v a r i a b l e s . Drainage and Bj horizon percent nitrogen are the only v a r i a -bles s i g n i f i c a n t l y correlated with the f i r s t canonical axis (Table 21). Coastal Tsuga-Blechnum-Polystichum f o r e s t s (T2), with the largest scores on the f i r s t a x is, are associated with productive s i t e s , higher B^ horizon % N, and better drainage. Elevation, percent slope, and topographic p o s i t i o n are strongly correlated with the second canonical axis (Table 21). The coastal wet Thuja forests (T5) and the c o a s t a l Thuja forests (T4), positioned toward the top of the second axis, were .found con s i s t e n t l y at low elevations on l e v e l or moderately sloping t e r r a i n . These environ-mental va r i a b l e s also were strongly correlated with the r e c i p r o c a l ave-raging ordination axes of the vegetation data (Fig. 8a; Table 10). 69 4. ABIES TYPES The Abies type centroids are not as c l e a r l y separated on the f i r s t two canonical axes as are those of the other groups (Fig. 13). This p a r t l y r e f l e c t s the impression of overlap caused by the larger confidence c i r c l e s of the centroids, which are generally based on fewer p l o t s than i n the other groups, and p a r t l y the use of only four envi-ronmental variables i n the canonical analysis. This was necessary since the computer program used would not perform the analysis with a larger set of v a r i a b l e s . The four v a r i a b l e s used were preselected with the use of a stepwise discriminant a n a l y s i s , s e l e c t i n g the environmental v a r i a -bles which permitted the maximum separation of the community types (Appendix 4). The montane Abies-Streptopus f o r e s t s (A4) and the Tsuga- Blechnum-Polystichum forests (A7) are at opposite ends of the f i r s t cano-n i c a l axis. These are the most environmentally d i f f e r e n t types within the Abies group (Fig. 13; Table 19). Based on the four variables used, the Abies-Streptopus forests (A4) are markedly d i f f e r e n t environmentally from, a l l other community types of the Abies group (Fig. 13; Table 19). Of p a r t i c u l a r i n t e r e s t i s the notable environmental difference between t h i s community type and the lowland Abies forests (A5). Despite the en-vironmental diff e r e n c e both community types show strong vegetational si m i -l a r i t i e s (Fig. 9a; Tables 26 and 27). Elevation and organic horizons thickness are strongly correlated with the f i r s t canonical axis (Table 21). Stands of the Abies-Streptopus f o r e s t s (A4), at the p o s i t i v e end of the f i r s t a x is, occur at the highest elevations within the Abies group. The second axis also i s correlated with elevation and % slope (Table 21); 70 thus, the lowland Abies forests (A5), the Tsuga-Gaultheria-Blechnum forests (A6), and the Tsuga-Blechnum-Polystichum forests (A7), a l l found at low elevations on moderate to gentle slopes, are grouped toward the lower end of the second axis. Montane Tsuga-Abies-Gaultheria forests (Al) appear environmentally s i m i l a r to the montane Abies-Tsuga forests (A2) (Fig. 13; Table 19), but t h i s could be an a r t i f a c t of the low number of environ-mental variables used. A better i l l u s t r a t i o n of environmental r e l a t i o n -ships within the Abies group i s obtained through the canonical analysis of a l l the community types from a l l the vegetation groups, where a l l the environmental variables were u t i l i s e d (Fig. 14; Table 20). 71 5. ALL TYPES AND THE SUBALPINE GROUP The d i s t r i b u t i o n of community type centroids on the f i r s t two canonical v a r i a t e s ( Fig. 14) corresponds c l o s e l y to the general pattern shown i n the analysis of the vegetation groups (Fig. 13). Furthermore, the cor r e l a t i o n s between environmental v a r i a b l e s and canonical axes show the same trends i n both cases (Table 21). Although the general patterns of both analyses are s i m i l a r , the canonical analysis of separate types i n d i -cates that some community types are environmentally more s i m i l a r to types belonging to other vegetation groups (Fig. 14; Table 20). For example, the montane Tsuga-Abies-Gaultheria forests (Al) are environmentally more s i m i l a r to the montane Tsuga forests (P6) and the montane Tsuga-Gaultheria forests (P7) , of the Pseudotsuga group, than to any other community type of the Abies group (Fig. 14; Table 20). These community types also are s i m i l a r v egetationally (Tables 22, 23, 26 and 27). The coa s t a l Tsuga- Blechnum-Polystichum f o r e s t s (T2) of the Thuja groups, and the Tsuga- Blechnum-Polystichum forests (A7) of the Abies group are both environ-mentally ( F i g . 14; Table 20) and ve g e t a t i o n a l l y s i m i l a r (Tables 24, 25, 26 and 27). The two environmentally most s i m i l a r community types are the Pseudotsuga-Berberis forests (P4) and the montane Tsuga forests (P6), based on the D 2 value (Table 20). The environmentally most d i s s i m i l a r community types are the coa s t a l dry Pinus forests (D2) and the L y s i c h i - tum variant of the Floodplain f o r e s t s (F2) I.(Table 20). Relationships between community types detected i n the canonical analyses of separate vegetation groups generally are maintained i n the combined types an a l y s i s ; however, the coa s t a l Thuja f o r e s t s (T4) appear environmentally most s i m i l a r to the montane coa s t a l Thuja forests (T3), than to the coastal wet Thuja 72 forests (T5), i n the combined analysis (Tables 18 and 20). The canonical analysis of a l l the community types i s f e l t to represent environmental r e l a t i o n s h i p s more accurately than the analysis of separate vegetation groups. Possibly because of the greater ranges of environmental v a r i a -t i o n when a l l types are analysed together. These r e s u l t s also could help to redefine the community type c l a s s i f i c a t i o n ( e g . merging types T2 and A7, as w e l l as A l and P7) , although such was not done i n t h i s t h e s i s . These community types (T2, A7, A l , P7) were situated at the boundaries of the three vegetation groups separated i n the 140 pl o t s r e c i p r o c a l averaging ordination (Fig. 6). The two pairs of community types which are d i f f e r e n t i a t e d v e g e t a t i o n a l l y along an elevation gradient both show high o v e r a l l environmental s i m i l a r i t i e s (P4 and P6, T3 and T4). This may ind i c a t e that no e c o l o g i c a l f a c t o r , other than elevation (detected by the d i r e c t ordinations, Figs 7b and 8b), i s responsible for the vege-t a t i o n a l differences observed (Figs. 7a and 8a; Tables 22, 23, 24 and 25). C. DESCRIPTION OF COMMUNITY TYPES The vegetation and e c o l o g i c a l c h a r a c t e r i s t i c s of the community types delineated within the r e c i p r o c a l averaging ordinations (Figs. 5, 7a, 8a and 9a) are described i n t h i s section. The composition, s t r u c -ture and d i v e r s i t y of the various vegetation s t r a t a are described b r i e f l y . The geographical d i s t r i b u t i o n , topographical c h a r a c t e r i s t i c s s o i l c h a r a c t e r i s t i c s and disturbance h i s t o r y are also outlined f o r each community type. S i m i l a r i t i e s between community types are i n d i c a t as well as s i m i l a r i t i e s with other community types or associations described previously for coastal B r i t i s h Columbia and, when possible, for Washington and Oregon. The community types within the Pinus contorta vegetation group are described f i r s t , followed by community types of the Pseudotsuga group, the Thuja group, the Abies group and the Floodplain group. Last to be described i s the Subalpine vegetation group which was not subdivided i n t o community types. 74 1. PINUS CONTORTA VEGETATION GROUP These open and low stature forests (average maximum height i s 18 m) are strongly dominated by Pinus contorta. This i s the only commu-n i t y type within the study area where Arbutus menziesii i s always present. Pseudotsuga menziesii seems to be regenerating w e l l (Table 22). At 30.7 m2/ha, the mean t o t a l basal area i s the second lowest f o r the com-munity types described i n t h i s study (the lowest i s found i n coastal dry Pinus f o r e s t s , of the same vegetation group). The mean tree density (700 trees/ha) i s among the highest. The shrub and bryophyte-lichen s t r a t a are among the r i c h e s t found i n the study area (Table 23). A large coverage of Vaccinium ovatum and the presence of Arctostaphylos columbiana characterize the shrub stratum (under 1.5 m i n height). Several herb species such as Apocynum androsaemifolium, Cryptogramma c r i s p a , Danthonia  spicata and S e l a g i n e l l a w a l l a c e i are r e s t r i c t e d almost e n t i r e l y to t h i s community type. The bryophyte-lichen stratum i s characterized by an abundance of lichens (Cladina r a n g i f e r i n a and many Cladonia species) growing on large bare rock patches representing 28 % of the ground sur-face (Table 23). This community type was found only at low elevations i n the inland portion of the study area around Port A l b e r n i . I t occurs on rock outcrops, predominantly south facing. The s o i l s are very shallow, average 15 cm i n depth, and are very r a p i d l y drained. The organic horizons are very thi n and roots are abundant down to the bedrock (Appendix 2). F i r e i s probably responsible for the establishment of Pinus contorta and evidence 75 of f i r e i s abundant i n a l l stands. Some windthrow also has occurred. The dry Pinus-Pseudotsuga f o r e s t s are quite s i m i l a r to the coastal dry Pinus forests (D2), which occupy s i m i l a r habitats near the coast (Figs. 5 and 14). They also have f l o r i s t i c s i m i l a r i t i e s to the dry Pseudotsuga forests (PI) (Tables 22 and 23). Kraj i n a (1969) l i s t s several biogeocoenoses (numbers 6, 12, 19 and 29) with l i s t s of species s i m i l a r to those of the dry Pinus-Pseudo- tsuga f o r e s t s . Kojima and Kra j i n a (1975) describe a s i m i l a r Arbutus  menziesii stand on a rock outcrop i n Strathcona P r o v i n c i a l Park, north of the area studied here. McMinn's (1960) Pseudotsuga-Gaultheria- P e l t i g e r a a s s o c i a t i o n also i s s i m i l a r , although probably i s not as x e r i c . Coastal dry Pinus f o r e s t s (D2) Although s i m i l a r i n structure to the dry Pinus-Pseudotsuga f o r e s t s , the coastal dry Pinus forests have several co-dominant tree species, giving them the r i c h e s t tree stratum i n the study area. Thuja p l i c a t a , Chamaecyparis nootkatensis and Tsuga heterophylla are regenerating w e l l on these s i t e s (Table 24). The mean t o t a l basal area i s the lowest i n the study area (30.2 m2/ha) and tree density i s very high (695 trees/ha) as a consequence of numerous small trees (Table 24). The shrub layer, less than 1.5 m i n height, i s dominated by Gaultheria shallon and Va c c i - nium ovatum. The herb stratum has a very low t o t a l percent coverage and i s r e l a t i v e l y poor i n species. In contrast, the bryophyte-lichen layer has a very high coverage and i s the r i c h e s t of a l l the community types recognized (Table 25). Some herb species such as Danthonia spicata, 76 Saxifraga ferruginea and S e l a g l n e l l a wallacei are r e s t r i c t e d to t h i s community type near the coast. Numerous bare rock surfaces (26 % cove-rage) have a r i c h assemblage of lichens and mosses including Cladina species, Cladonia species, Pleurozium schreberi, Polytrichum and Rhaco- mitrium species (Table 25). This community type i s r e s t r i c t e d to low elevation, sloping rock outcrops near the coast. These s i t e s are very r a p i d l y drained and have very shallow s o i l s (average s o i l depth i s 11 cm). The organic horizons are t h i n and roots extend to the bedrock (Appendix 2). No evidence of f i r e was found and wind disturbance appears minimal. This community type i s most s i m i l a r to the dry Pinus-Pseudotsuga forests (DI), occupying s i m i l a r s i t e s inland (Figs. 5 and 14). No previous descriptions of community types s i m i l a r to the c o a s t a l dry Pinus forests seem to e x i s t . However, t h i s community type represents a coastal v a r i a t i o n of the Dry Pinus-Pseudotsuga f o r e s t s (DI) for which published equivalent descriptions were found. 77 2. PSEUDOTSUGA VEGETATION GROUP Drv_Pseudotsuga_forests (PI) This community type has a r e l a t i v e l y low canopy (average height i s 44 m), low mean t o t a l basal area (86.2 m 2/ha), and low mean tree density (300 trees/ha). Pseudotsuga menziesii dominates and appears to be the species regenerating best (Table 22). The shrub stratum i s r i c h i n species and i t s coverage i s among the largest within the Pseudo- tsuga group. The herb layer i s the r i c h e s t found i n the study area (Table 23). The most conspicuous shrubs are Gaultheria shallon (1 m high), Berberis nervosa and Vaccinium ovatum, while the herbs Chimaphila  umbellata, Festuca o c c i d e n t a l i s and Pteridium aquilinum are p a r t i c u l a r l y abundant. Boschniakia hookeri, a root parasite of Gaultheria shallon, i s always present. The bryophyte-lichen stratum i s dominated by Stoke- s i e l l a oregana and Hylocomium splendens, but otherwise shares many spe-cies with the dry Pinus-Pseudotsuga f o r e s t s (Table 23). The dry Pseudotsuga f o r e s t s were found only inland near Port A l b e r n i . They occupy low elevations, strong to extreme slopes {Canada S o i l Survey Committee, 1978) with shallow, r a p i d l y drained s o i l s (average s o i l depth i s 54 cm). The organic horizons are very thin and roots extend deep into the mineral s o i l (Appendix 2). This community type often occurs immediately downslope of the dry Pinus-Pseudotsuga f o r e s t s (Dl). Most s o i l s are Orthic D y s t r i c Brunisols developing on c o l l u v i a l material (Table 29). F i r e has occurred f a i r l y recently i n a l l the stands which probably explains why Pseudotsuga menziesii, with i t s f i r e r e s i s t a n t bark, dominates. The dense shrub coverage may also be f i r e induced owing 78 to the improved conditions f or shrub growth following f i r e . Many of the stands studied almost e n t i r e l y consist of large, widely spaced Pseudotsuga menziesii trees with charred bark. This type has vegeta-t i o n a l and environmental s i m i l a r i t i e s with the Pseudotsuga-Thuja-Acer fo r e s t s (P2) and the Pseudotsuga-Linnaea f o r e s t s (P3) , although the many species of dry s i t e s i t shares with the dry Pinus-Pseudotsuga f o r e s t s (DI) are an i n d i c a t i o n of i t s d r i e r moisture regime (Tables 22 and 23; Figs. 13 and 14). The Dry Pseudotsuga forests have s i m i l a r i t i e s with numerous commu-n i t i e s or associations described f o r B r i t i s h Columbia, such as the Pseu- dotsuga-Arbutus/Gaultheria habitat type of Beese (1981), the Pseudotsuga- Gaultheria association of McMinn (1960), and the Gaultheria shallon asso-c i a t i o n of Kojima and K r a j i n a (1975). Also s i m i l a r , i s the Pseudotsuga/ Holodiscus-Gaultheria association described by Franklin and Dyrness (1973) for dry s i t e s within the Oregon Coast Ranges. Pseudotsuga-Thuja-Acer f o r e s t s (P2) This community type has one of the best developed tree s t r a t a i n the Pseudotsuga group (mean maximum tree height i s 64 m, mean t o t a l basal area i s 132.5 m2/ha (Table 22)). The tree stratum i s also among the r i c h e s t found i n the study area, and although dominated by Pseudo- tsuga menziesii, i t i s characterized by the deciduous trees Acer macro- phyllum and Cornus n u t t a l l i i . Most tree species seem to be regenerating w e l l (Table 22). The low and sparse shrub layer (under 1 m i n height) i s dominated by Berberis nervosa, Gaultheria shallon and Rubus ursinus. 79 The herb stratum i s also r i c h , with high coverages of Achlys t r i p h y l l a , Festuca s u b u l i f l o r a , Linnaea b o r e a l i s , Polystichum muniturn and T r i e n t a l i s  l a t i f o l i a . S t o k e s i e l l a oregana and Hylocomium splendens share dominance i n the bryophyte-lichen layer. Leucolepis menziesii, a moss of moist s o i l s (Schofield, 1976), i s r e l a t i v e l y abundant (Table 23). The Pseudotsuga-Thuja-Acer f o r e s t s occur only inland within the study area, close to Port A l b e r n i . They occupy mid-slope positions on strong to extreme, mostly south facing slopes at low elevations (Fig. 7b). The s o i l s are moderately deep (average s o i l depth i s 65 cm) and well drained, with r e l a t i v e l y high pH values (LFH average = 4.8, average = 5.2). The organic horizons are very thin and rooting occurs throughout the mineral s o i l (Appendix 2). Most s o i l s are Orthic Humo-Ferric Podzols developing on c o l l u v i a l material (Table 29). The mid-slope topographic p o s i t i o n , as well as the vegetation, suggest that seepage probably contributes s i g n i f i c a n t amounts of water and nutrients to the s o i l s . Evidence of f i r e i s abundant, i n the form of buried charcoal and charred bark on Pseudotsuga trees. Vegetational and environmental s i m i l a r i t i e s between t h i s community type, the dry Pseudotsuga f o r e s t s (PI) and the Pseudotsuga-Linnaea f o r e s t s (P3) are high (Tables 22 and 23; Figs. 13 and 14), although the vegetation i s s u f f i c i e n t l y d i f f e r e n t to warrant the d i s t i n c t i o n made (Fig. 7a). Also, the moisture regime i s not as dry as i n the other two types. The Pseudotsuga/Holodiscus/Polystichum habitat type described f o r eastern Vancouver Island by Beese (1981) i s very s i m i l a r to t h i s commu-n i t y type. Both contain Acer macrophyllum and have s i m i l a r understories 80 (although Holodiscus d i s c o l o r i s more abundant i n the eastern Vancouver Island type). Beese (1981) found no previous de s c r i p t i o n of his type within B r i t i s h Columbia and suggested that i t may have been included i n other frequently described types where Polystichum muniturn dominates the herb layer. Of these, the Achlys-Polystichum association of Kojima and K r a j i n a (1975) comes closest to resembling the Pseudotsuga-Thuja-Acer f o r e s t s . This community type probably represents the " c l a s s i c a l " Poly- stichum type i n what would be the equivalent of the Coastal wetter Douglas-fir subzone i n t h i s study area (Klinka et_ a l . , 1979), while the Tsuga-Pseudotsuga-Polystichum f o r e s t s (P5) , represent the Polystichum type i n what would be the Coastal d r i e r Western Hemlock subzone i n t h i s study area (Klinka et a l . , 1979). Pseudotsuga-Linnaea f o r e s t s (P3) Although of similar, composition to the tree stratum of the Pseudo-tsuga-Thuja-Acer f o r e s t s , the tree stratum of t h i s community type i s lower (average maximum height i s 48 m) and has a much smaller mean basal area (89.4 m2/ha, Table 22). Tsuga heterophylla becomes the second dominant a f t e r Pseudotsuga menziesii, and deciduous trees are often absent. Tsuga heterophylla shows the best regeneration (Table 22). This community type has a shrub stratum characterized by a high coverage of Gaultheria shallon under 1 m i n height. The r i c h herb layer i s s i m i l a r to that of the Pseudotsuga-Thuja-Acer f o r e s t s (P2) , except that Linnaea b o r e a l i s a t t a i n s a high coverage and Polystichum muniturn i s r e l a t i v e l y unimportant. Hylocomium splendens dominates the bryophyte-lichen stratum covering most of the f o r e s t f l o o r (Table 23). 81 This community type occurs mostly at mid-elevations, on mid- and upper-slopes (Fig. 7b), inland within the study area near Port Al b e r n i . I t i s found on strong to extreme slopes with moderately deep (average s o i l depth i s 65 cm), well drained s o i l s , formed mostly on c o l l u v i a l material. Organic horizons and.mineral horizons have r e l a t i v e l y high pH values (LFH average = 4.9; Bj average = 5.2). The organic horizons are thin and rooting occurs throughout the mineral s o i l (Appendix 2). A l l s o i l s are Orthic Humo-Ferric Podzols (Table 29). The higher up-slope p o s i t i o n , as well as the absence of c e r t a i n moisture i n d i c a t o r plant species (Tables 22 and 23), suggest that moisture input through seepage i s not as pronounced here as i n the Pseudotsuga-Thuja-Acer f o r e s t s . Evidence of f i r e was present i n a l l stands. S i m i l a r i t i e s between t h i s type, the dry Pseudotsuga f o r e s t s (PI) and the Pseudotsuga-Thuja-Acer fo r e s t s (P2) are evident (Tables 22 and 23; Figs. 13 and 14). The Pseudotsuga-Linnaea f o r e s t s resemble the Pseudotsuga/Gaultheria- Berberis habitat type described by Beese (1981) f o r eastern Vancouver Island. Other s i m i l a r i t i e s are with the biogeocoenosis 5 of K r a j i n a (1969) and the Salal-Oregon grape-Douglas-fir biogeocoenotic zonal type of Klinka e_t a l . (1979) for the D r i e r Maritime Coastal Douglas-fir Sub-zone (the Pseudotsuga-Linnaea f o r e s t s are situated on d r i e r s i t e s within the Wetter Subzone found i n t h i s study area). Beese (1981) l i s t s several other s i m i l a r community types described f o r B r i t i s h Columbia. Similar types i n Oregon and Washington are summarized by Franklin and Dyrness (1973). 82 E-e"-g£gBg al!gEkgE±g-_g rgg£g (P^) (Fig. 18b) The Fseudotsuga-Berberis f o r e s t s have one of the best developed tree s t r a t a within the Pseudotsuga group (mean maximum tree height i s 58 m and, mean t o t a l basal area i s 138.4 m2/ha (Table 22)). Pseudo- tsuga menziesii dominates, with Tsuga heterophylla as a close second. Tree regeneration i s strongly dominated by Tsuga heterophylla (Table 22). Although the shrub layer i s s i m i l a r i n most community types of the Pseudotsuga group, Berberis nervosa i s notably abundant i n the low shrub layer of t h i s type (average height under 1 m). The low cover, but r i c h , herb stratum has no p a r t i c u l a r l y c h a r a c t e r i s t i c species. Hylocomium  splendens and S t o k e s i e l l a oregana again share dominance i n the bryophyte-lichen layer (Table 23). The Pseudotsuga-Berberis f o r e s t s are found only inland within the study area. They are found mostly on mid-slope topographic positions at mid-elevations (Fig. 7b). They occur mostly on very strong slopes with deep, r a p i d l y drained s o i l s . The organic horizons are moderately thick (average of 8.6 cm) and rooting occurs throughout most of the mineral s o i l (Appendix 2). Most s o i l s belong to the Orthic Humo-Ferric Podzol subgroup (Table 29). The majority of stands show evidence of f i r e d i s -turbance. This community type has s i m i l a r i t i e s with the Montane Tsuga for e s t s (P6), which are usually found on s i m i l a r s i t e s but at higher elevations. I t also has s i m i l a r i t i e s with the Tsuga-Pseudotsuga-Polysti- chum fo r e s t (P5), often found on adjacent, lower-slope topographic po-s i t i o n s (Figs. 7a and b, 13 and 14; Tables 22 and 23). 83 The Pseudotsuga-Berberls f o r e s t s are most s i m i l a r to the "moss" assoc i a t i o n considered to be the zonal vegetation type f o r lower eleva-tions i n Strathcona P r o v i n c i a l Park by Kojima and K r a j i n a (1975). This association i s dominated by Hylocomium splendens and S t o k e s i e l l a oregana i n the bryophyte layer, and Berberis nervosa i n the shrub layer. The moss association i s interpreted as being intermediate i n moisture regime to associations^of d r i e r s i t e s , dominated by Gaultheria shallon, and associations of wetter s i t e s , dominated by Polystichum munitum (Kojima and K r a j i n a , 1975). The same i n t e r p r e t a t i o n i s reached here f o r the Pseudotsuga-Berberis f o r e s t s (Fig. 7a and b; Tables 22 and 23). Krajina's (1969) biogeocoenoses 18 and 25, and McMinn's (1960) Pseudotsuga-Tsuga- Hylocomium association also correspond to these f o r e s t s . The Tsuga/ Gaultheria-Berberis/Achlys habitat type of Beese (1981) i s somewhat simi-l a r , but has much r i c h e r herb and shrub s t r a t a . The Tsuga/Rhododendron/ Berberis association described by Franklin and Dyrness (1973) for the Tsuga heterophylla Zone of the western Oregon Cascade Range, i s very s i m i l a r to the Pseudotsuga-Berberis f o r e s t s , although the l a t t e r have no Rhododendron macrophyllum. According to Franklin and Dyrness (1973), t h i s association t y p i f i e s the c l i m a t i c climax for the western Oregon Cascades. The Pseudotsuga-Berberis f o r e s t s may also be considered the c l i m a t i c climax i n the v i c i n i t y of Port A l b e r n i . I-HE-I-S-H-2HEH--l-2_Z---£l}HlB_£2£^--- (Fig. 18c). This community type has the largest mean t o t a l basal area (158.4 m 2/ha), and the second larges t mean maximum tree height (61 m) i n the Pseudotsuga group (Table 22). Tsuga heterophylla and Pseudotsuga menziesii 84 share dominance nearly equally i n the tree stratum, but only Tsuga hete- rophylla i s regenerating w e l l (Table 22). The shrub and bryophyte-lic h e n layers have small coverages and are poor i n species; the herb stratum has a high coverage of Polystichum munitum (Table 23; Fig. 18c). The Tsuga-Pseudotsuga-Polystichum f o r e s t s are located c e n t r a l l y inland within the study area, almost e x c l u s i v e l y on lower-slopes (Fig. 7b) where they receive seepage and runoff water. They occur from low eleva-t i o n up to 500 m, on generally south fa c i n g , steep to gentle slopes (Fig. 7b). They are always found on deep s o i l s (average; s o i l depth i s 100 cm) formed mostly of very r a p i d l y to r a p i d l y drained c o l l u v i a l mate-r i a l . Some stands are found on nearly l e v e l f l u v i a l m aterial, with slower drainage, but only i n the d r i e s t part of the study area (plots 1 and 17). The organic horizons are moderately thick (average of 10 cm) and rooting occurs throughout most of the mineral s o i l . Most s o i l s of t h i s community type are c l a s s i f i e d as Orthic Humo-Ferric Podzols (Table 29). Traces of f i r e are evident i n most of the stands, and f i r e i s believed to be at the o r i g i n of a l l the stands. This community type shows s i m i l a r i t i e s to the Pseudotsuga-Berberis forests (P4), a commonly adjacent type on upslope topographical positions (less influenced by seepage water), and also to the Montane Tsuga f o r e s t s (P6) (Figs 7a and b, 13 and 14; Tables 22 and 23) . The Tsuga-Pseudotsuga-Polystichum forests are undoubtedly very s i m i l a r to the many Pseudotsuga-Polystichum community types or associa-tions described f o r coastal B r i t i s h Columbia, Washington and Oregon. For B r i t i s h Columbia, the biogeocoenoses 2b and 24 of Kra j i n a (1969), 85 t h e A c h l y s - P o l y s t i c h u m a s s o c i a t i o n of K o j i m a and K r a j i n a ( 1 9 7 5 ) , the P o l y s t i c h u m f o r e s t t y p e of O r l o c i (1961) , t h e P s e u d o t s u g a - P o l y s t i c h u m a s s o c i a t i o n of M cMinn ( 1 9 6 0 ) , and t h e T s u g a - P o l y s t i c h u m h a b i t a t t y p e of Beese (1981) , a r e comparable t o t h e T s u g a - P s e u d o t s u g a - P o l y s t i c h u m f o r e s t s . F r a n k l i n and D y r n e s s (1973) d e s c r i b e a s i m i l a r Tsuga h e t e r o p h y l l a / P o l y - s t i c h u m muniturn community t y p e f o r Washington and Oregon based on s e v e r a l p u b l i s h e d d e s c r i p t i o n s . MontaneJTsuga f o r e s t s (P6) These f o r e s t s have a h i g h mean t o t a l b a s a l a r e a (114.5 m 2/ha) but a r e l a t i v e l y low s t a t u r e (mean maximum h e i g h t of 50 m) ( T a b l e 2 2 ) . Tsuga  h e t e r o p h y l l a dominates t h e t r e e s t r a t u m , and i s r e g e n e r a t i n g w e l l , w h i l e P s e u d o t s u g a m e n z i e s i i becomes t h e second dominant ( T a b l e 2 2 ) . The s p e c i e s poor shrub l a y e r i s c h a r a c t e r i z e d by a h i g h c o v e r a g e of V a c c i n i u m p a r v i - f o l i u m , a v e r a g i n g 1 m i n h e i g h t . The s p a r s e herb s t r a t u m shows no c h a -r a c t e r i s t i c s p e c i e s . R h y t i d i o p s i s r o b u s t a , a moss a s s o c i a t e d w i t h h i g h e l e v a t i o n s ( S c h o f i e l d , 1 9 76), i s o f t e n abundant i n t h e b r y o p h y t e - l i c h e n l a y e r ( T a b l e 2 3 ) . T h i s community t y p e o c c u r s w i t h i n t h e c e n t r a l and i n l a n d p o r t i o n of t h e s t u d y a r e a , m o s t l y above 400 m i n e l e v a t i o n ( F i g . 7b). I t i s f o u n d on moderate t o s t e e p m i d - s l o p e s and u p p e r - s l o p e s , o v e r deep, r a p i d l y t o w e l l d r a i n e d c o l l u v i a l m a t e r i a l . The o r g a n i c h o r i z o n s a r e m o d e r a t e l y t h i c k ( a v e r a g e of 8.5 cm) and r o o t i n g o c c u r s t h r o u g h o u t most of t h e mine-r a l s o i l ( A p p endix 2 ) . Most s o i l s were c l a s s i f i e d as O r t h i c H u m o - F e r r i c P o d z o l s ( T a b l e 2 9 ) . E v i d e n c e of f i r e was f o u n d i n n e a r l y a l l s t a n d s . 86 This community type shows s i m i l a r i t i e s to the Pseudotsuga-Berberis fo r e s t s (P4) with which i t intergrades at lower elevations (Figs. 7a and b, 13 and 14; Tables 22 and 23). McMinn's (1960) Pseudotsuga-Tsuga- Hylocomium association has a bare forest, f l o o r variant which i s s i m i l a r to the Montane Tsuga f o r e s t s . Montane_Tsuga-Gaultheria f o r e s t s (P7) (Fig. 18a) This community type has the smallest mean t o t a l basal area (86 m2/ha) and mean maximum tree height (41 m) of the Pseudotsuga group. Tsuga heterophylla dominates the tree, sapling, and seedling s t r a t a (Table 22). The understory i s characterized by a nearly continuous, species poor shrub layer, dominated by low (< 1 m) Gaultheria shallon (Fig. 18a). The herb stratum i s species poor and very sparse. Rhyti- diadelphus loreus i s abundant i n the bryophyte-lichen layer (Table 23). The montane Tsuga-Gaultheria f o r e s t s occur inland within the study area, generally above 500 m, on moderate to extreme slopes (Fig. 7b). They are found on upper-slopes or ridges, on deep s o i l s formed mostly by c o l l u v i a l material. The organic horizons are moderately thick (average of 10 cm) and rooting occurs throughout most of the mineral s o i l (Appen-dix 2). Nearly a l l s o i l s are r a p i d l y to well drained Orthic Humo-Ferric Podzols (Table 29). Half of the stands show no evidence of f i r e d i s t u r -bance, but f i r e probably remains at the o r i g i n of a l l the stands. This community type has s i m i l a r i t i e s with the Pseudotsuga-Linnaea f o r e s t s (P3) of which i t appears to be a high elevation equivalent with Tsuga regene-r a t i o n . I t also has s i m i l a r i t i e s with the montane Tsuga-Abies-Gaultheria fo r e s t s (Al) (Figs. 7a and b, 9a and b, and 14; Tables 22, 23, 26 and 27). 87 The montane Tsuga-Gaultheria f o r e s t s are s i m i l a r to the Pseudo- tsuga-Tsuga-Gaultheria association of McMinn (1960) and the Tsuga- Gaultheria habitat type of Beese (1981). This type i s also s i m i l a r to Kojima and Krajina's (1975) Gaultheria shallon association, although Tsuga heterophylla does not regenerate s u c c e s s f u l l y i n t h e i r association. Del Moral and Long (1977) describe a s i m i l a r Pseudotsuga-Gaultheria com-munity type f o r the montane fo r e s t s of western Washington. 88 3. THUJA VEGETATION GROUP Coastal_drv_Thuja f o r e s t s (TI) The coastal dry Thuja f o r e s t s have the lowest mean t o t a l basal area (86 m2/ha) within the Thuja group; they also are low i n stature (mean maximum tree height of 30 m). Thuja p l i c a t a , followed by Tsuga  heterophylla, Pseudotsuga menziesii and Taxus b r e v i f o l i a , dominate the tree stratum. This i s the only community type within the Thuja group with an appreciable amount of Pseudotsuga menziesii. Thuja p l i c a t a and Tsuga heterophylla seem to be regenerating very w e l l (Table 24). The dense and continuous shrub layer i s dominated by Gaultheria shallon and Vaccinium ovaturn, averaging 2 and 3 m high, re s p e c t i v e l y . The herb s t r a -tum i s r e l a t i v e l y poor and sparse f o r the Thuja group, and consists nearly e n t i r e l y of Blechnum spicant. The abundance of Rhytidiadelphus  loreus and Hylocomium splendens characterizes the w e l l developed bryo-phyte-lichen layer (Table 25). This community type i s r e s t r i c t e d to the coastal part of the study area. I t i s found at low elevations on very strong to extreme slopes, mostly on ridges (Fig. 8b). S o i l s are r a p i d l y drained and very shallow (average s o i l depth i s 16 cm). The s o i l s of most stands are Typic F o l i -sols with organic horizons exceeding 10 cm i n thickness and d i r e c t l y overlying the bedrock (Appendix 2; Table 29). No evidence of f i r e was found i n these stands, but a l l show signs of wind disturbance. The r e l a -t i v e l y dry habitats occupied by t h i s community type contribute to i t s vegetational s i m i l a r i t i e s with the co a s t a l dry Pinus f o r e s t s (D2) (Tables 24 and 25). I t also i s v e g e t a t i o n a l l y s i m i l a r to the coastal wet Thuja 89 f o r e s t s (T5) , although the habitats are e n t i r e l y d i f f e r e n t (Fig. 8a and b; Tables 24 and 25). No references to f o r e s t types s i m i l a r to the coastal dry Thuja fo r e s t s could be found. Coastal Tsuga-Blechnum-Polvstichum_forests (T2) This community type has a large mean t o t a l basal area (142.3 m2/ha) and excellent tree height (average of 52 m) (Table 24). Tsuga hetero- phylla dominates the tree stratum and i t s regeneration occupies nearly the en t i r e sapling and seedling layers (Table 24). Abies amabilis and Thuja p l i c a t a are, re s p e c t i v e l y , the second and t h i r d dominants. The shrub.layer i s comprised mainly of scattered, 2 m high Vaccinium p a r v i - folium. The herb stratum, although poor i n species, i s w e l l developed and i s characterized by an abundance of Blechnum spicant and Polystichum  muniturn. The bryophyte-lichen layer i s poor and has low coverage (Table 25). This community type i s found i n the coastal part of the study area. I t occurs from low to mid-elevations on very strong to extreme slopes. A l l stands are situated on mid-slope topographic positions (Fig. 8b). S o i l s are deep, well to moderately w e l l drained, developing mostly on c o l l u v i a l material. Half of the stands are found on ancient rock s l i d e c o l l u v i a l material. The organic horizons are thick (average of 15 cm) and nearly half of the rooting occurs i n them (Appendix 2). Most s o i l s encountered are Orthic Ferro-Humic Podzols (Table 29). No 90 evidence of f i r e was found i n any of the stands, but most have been sub-jected to some wind disturbance. This community type shows some s i m i l a -r i t i e s with the Tsuga-Blechnum-Polystichum f o r e s t s (A7), a community type with less Abies amabilis and Thuja p l i c a t a , and one which i s not s t r i c t l y c o astal i n character (Fig. 14; Tables 24, 25, 26 and 27). The coa s t a l Tsuga-Blechnum-Polystichum f o r e s t s generally corres-pond to the biogeocoenotic types described by Kli n k a et_ a l . (1979) f o r th e i r Estevan Submontane and West Vancouver Island Submontane Wetter Coastal Western Hemlock biogeoclimatic subzone varian t s . The coas t a l Tsuga-Blechnum-Polystichum f o r e s t s appear to have better drainage than the more widespread coastal Thuja f o r e s t s (T4). Half of the stands of the c o a s t a l Tsuga-Blechnum-Polystichum f o r e s t s were found on old land-s l i d e s , which probably created improved drainage and nutrient conditions on these s i t e s . 92_g-£-_M2--£Hg_I^Hl---2££-^s (T^) This community type has the largest mean t o t a l basal area (187.3 m2/ha) within the Thuja group; the mean maximum tree height i s 42 m (Table 24). These f o r e s t s are dominated by Thuja p l i c a t a followed by Tsuga heterophylla and Abies amabilis. A l l species are regenerating well, except possibly Thuja p l i c a t a (Table 24). The species poor shrub stratum has a high coverage, with large contributions by 1 m high Gaul- t h e r i a shallon and 2.5 m high Vaccinium species. The herb layer i s the ri c h e s t within the Thuja group, but Blechnum spicant remains the dominant species. The r i c h bryophyte-lichen layer i s c h a r a c t e r i s t i c of the Thuja group, but otherwise i s not d i s t i n c t i v e (Table 25). 91 The coastal montane Thuja f o r e s t s are found only near the coast from mid-to high elevations, mostly on mid-slope topographic positions of very strong to steep slopes (Fig. 8b). They occur on deep, well to poorly drained s o i l s . The organic horizons are thick (average of 14 cm) and rooting i s mostly l i m i t e d to these horizons (Appendix 2). The s o i l s , mostly Gleyed or Orthic Ferro-Humic Podzols, or Humic Gleysols, have developed on a v a r i e t y of materials (Table 29). Traces of f i r e d i s t u r -bance were not found, but many stands show signs of wind disturbance i n the form of i s o l a t e d uprooted trees. This community type i s very s i m i l a r to the coastal Thuja forests (T4) which are found at lower elevations on si m i l a r s i t e s (Figs. 8a and b, 13 and 14; Tables 24 and 25). Both types intergrade along an elevation gradient (Fig. 8b) and present s i m i l a r v i s u a l aspects, except f o r a greater abundance of Abies amabilis ( p a r t i -c u l a r l y i n the sapling and seedling s t r a t a ) i n the coastal montane Thuja forests (Table 24). The coastal montane Thuja forests do not appear to have been described previously. Coastal_T ;hu rla r_forests (T4) (Fig. 18d) The co a s t a l Thuj a forests have an impressive mean t o t a l basal area of 180.4 m2/ha (Table 24). Thuja p l i c a t a dominates, with Tsuga hetero- phylla and Abies amabilis as second and t h i r d dominants, re s p e c t i v e l y . These species are regenerating w e l l , although not abundantly i n the case of Thuja p l i c a t a (Table 24). The shrub stratum i s well developed, with a large coverage of Gaultheria shallon close to 2 m i n height, and several 92 Vaccinium species over 3 m i n height (Fig. 18d). The herb layer, one of the poorest i n the Thuj a group, i s strongly dominated by Blechnum  spicant (Fig. 18d). The bryophyte-lichen stratum i s r e l a t i v e l y r i c h and i s c h a r a c t e r i s t i c of the Thuja group (Table 25). The co a s t a l Thuja forests are found near the coast from low to mid-elevations on a v a r i e t y of topographical positions except ridges (Fig. 8b). This community type occurs on deep, generally imperfectly drained s o i l s , situated on l e v e l to strongly sloping t e r r a i n . The orga-ni c horizons are very thick (average of 20 cm) and most of the root mass i s r e s t r i c t e d to them (Appendix 2). The s o i l s almost i n v a r i a b l y show signs of B horizon gleying and cementation. They are mostly Humic Gley-s o l s , with some Ferro-Humic Podzols, Or t s t e i n and Duric Humo-Ferric Podzols (Table 29). Because of the frequent cementation of the mineral horizons, most seepage occurs i n the organic horizons (this was observed once during a rainstorm). Plot 24, although not coastal, receives abun-dant seepage water and supports vegetation t y p i c a l of coastal s i t e s . Very few stands showed traces of f i r e , but most had evidence of wind d i s t u r -bance by uprooted i n d i v i d u a l trees. This community type i s s i m i l a r to the coastal montane Thuja f o r e s t s (T3), found at higher elevations on s i m i l a r s i t e s (Figs. 8a and b, 13 and 14; Tables 24 and 25). No d e t a i l e d d e s c r i p t i o n of the coastal Thuja f o r e s t s of the west coast of Vancouver Island seems to have been published. K l i n k a et a l . (1979) l i s t the major species and e c o l o g i c a l c h a r a c t e r i s t i c s of f o r e s t s described as stands of "decadent" old-growth trees, with very dense and t a l l shrub layers. In the Estevan Submontane Wetter Maritime Coastal 93 Western Hemlock biogeoclimatic subzone variant these stands are nearly at c l i m a t i c climax because of the v i r t u a l absence of f o r e s t f i r e s (Klinka et a l . , 1979). These authors also note the considerable r e l i e f of the forest f l o o r i n these f o r e s t s caused by the continual windthrow of i n d i v i d u a l trees. Forests of a s i m i l a r nature are probably found a l l along the coast of B r i t i s h Columbia and Washington. Hines (1971) des-cribes a Tsuga-Picea/Gaultheria/Blechnum community type f o r north coastal Oregon which appears s i m i l a r to the Coastal Thuja f o r e s t s of Vancouver Island, e s p e c i a l l y i n the shrub and herb s t r a t a , where the dominants are i d e n t i c a l . The more southerly l o c a t i o n (and thus d r i e r climate) of the Oregoncstands may explain why they contain so l i t t l e Thuja p l i c a t a as compared to the Vancouver Island p l o t s . This community type has one of the lowest mean t o t a l basal areas of the Thuja group (87.7 m 2/ha), and i t also has the lowest mean maximum tree height (24 m). The mean tree density (855 trees/ha) i s the highest i n the study area and r e s u l t s from a large number of small trees (Table 24). Thuja p l i c a t a dominates the tree stratum with Tsuga heterophylla and Pinus contorta as co-dominants. Taxus b r e v i f o l i a i s always present. Thuja p l i c a t a and Tsuga heterophylla are regenerating w e l l (Table 24). A nearly impenetrable and continuous shrub layer i s dominated by 2 m high Gaultheria shallon and Vaccinium ovatum. Pyrus fusca, e s s e n t i a l l y r e s t r i c t e d to t h i s community type, often reaches 4 to 6 m i n height. The r e l a t i v e l y r i c h herb stratum has a large coverage and i s dominated by Blechnum spicant. The r i c h bryophyte-lichen stratum i s c h a r a c t e r i s t i c of the Thuja group (Table 25). 94 The coastal wet Thuja f o r e s t s occur very near the coast, close to sea l e v e l , always on l e v e l s i t e s (Fig. 8b). They are found on deep, poorly drained s o i l s on morainal or f l u v i a l deposits. The organic horizons are very thick (average of 20 cm) and contain most of the root mass (Appendix 2). Most s o i l s are Humic Gleysols (Table 29). Evidence of disturbance by f i r e or wind was found i n some stands. This community type has close vegetational s i m i l a r i t i e s with the coastal dry Thuja forests (TI), but these two types occur i n markedly d i f f e r e n t habitats (Fig.,. 8a and b) . The coastal wet Thuja f o r e s t s also have s i m i l a r i t i e s with the coastal Thuja f o r e s t s (Figs. 8a and b, 13 and 14; Tables 24 and 25). Communities very s i m i l a r i n appearance to the Coastal wet Thuja forests are described as Coastal forested swamps by Franklin and Dyrness (1973) f or western Washington's coastal p l a i n . K l i n k a et a l . (1979) •report that, on the west coast of Vancouver Island, Thuja p l i c a t a and Pinus contorta are the major species on f l a t areas and on the lower parts of gentle slopes when there i s a large water surplus. 95 4. ABIES VEGETATION GROUP This community type has a large mean t o t a l basal area (121 m2/ha) and a high mean tree density (700 trees/ha), but the smallest mean maxi-mum tree height (44 m) within the Abies group (Table 26). The tree stratum, the r i c h e s t within the Abies group, i s dominated by Tsuga hete- rophylla, Pseudotsuga menziesii and Abies amabilis, of which only Pseudo- tsuga menziesii i s not regenerating (Table 26). A continuous shrub layer over 1 m high, the r i c h e s t within the Abies group, i s dominated by Vac c i - nium alaskaense, Gaultheria shallon and V. parvifolium. The herb stratum i s the poorest i n species and the smallest i n t o t a l coverage within the study area. The bryophyte-lichen layer i s well developed and i s dominated by Rhytidiadelphus loreus (Table 27). The montane Tsuga-Abies-Gaultheria f o r e s t s are found mostly within the c e n t r a l part of the study area. They occur on generally south f a c i n g , strong to extreme slopes, from mid- to high elevations, mostly on upper-slope topographical positions (Fig. 9b). The deep, r a p i d l y to well drained s o i l s are formed mostly of c o l l u v i a l material. The organic horizons are moderately thick (average of 9.3 cm) and rooting i s shallow (mean e f f e c t i v e rooting depth of 19 cm) (Appendix 2). The s o i l s are Orthic Humo-Ferric Podzols (Table 29). A l l the stands show evidence of f i r e disturbance, some only as r e f l e c t e d by the abundance of Pseudotsuga  menziesii, and some by charcoal i n the s o i l . This community type has environmental s i m i l a r i t i e s to the montane Tsuga-Gaultheria f o r e s t s (P7) and the montane Tsuga f o r e s t s (P6) (Figs. 7b, 9b and 14), but i t d i f f e r s 96 veg e t a t i o n a l l y from them i n the abundance of Abies amabilis and Vac c i - nium alaskaense. Within the Abies group i t i s not p a r t i c u l a r l y s i m i l a r to other types, except f o r the presence of Abies amabilis regeneration (Figs. 9a and b, 13 and 14; Tables 26 and 27). The montane Tsuga-Abies-Gaultheria forests are s i m i l a r to the Chamaecyparis/Gaultheria habitat type described f o r eastern Vancouver Island by Beese (1981). In t h i s habitat type Abies amabilis i s rare i n the tree stratum, but seedlings are r e l a t i v e l y abundant and Gaultheria shallon dominates the shrub layer. The Abies amabilis/Gaultheria shallon association, described by Franklin and Dyrness (1973) f o r the Abies ama- b i l i s Zone i n southern Washington, i s somewhat rela t e d with a high G_. shallon coverage and a very poorly developed herb stratum. Montane Abies-Tsuga f o r e s t s (A2) These fo r e s t s have a high mean t o t a l basal area (146.5 m2/ha) and the lowest mean tree density (280 trees/ha) i n the study area (Table 26). Small trees (not including saplings) are scarce and most trees are found within a narrow range of s i z e - c l a s s e s . Tsuga heterophylla, Abies amabilis and Thuja p l i c a t a dominate the tree stratum with the former two species having equal dominance i n sapling and seedling layers (Table 26). The shrub stratum has a large coverage and i s dominated by Vaccinium a l a s - kaense over 1 m i n height. The herb layer, r e l a t i v e l y r i c h and of high coverage f o r the Abies group, i s characterized by Blechnum spicant. The bryophyte-lichen stratum has a small coverage and i s made up of species generally found within the Abies group (Table 27). 97 This community type i s found above 500 m i n elevation i n the cen-t r a l part of the study area (Fig. 9b). I t occurs on upper-slope positions of extreme slopes, over deep deposits of c o l l u v i a l or morainal material. The s o i l s are moderately well to imperfectly drained Gleyed Ferro-Humic Podzols (Table 29). The organic horizons are moderately thick (average of 10.5 cm) and contain almost a l l of the roots (Appendix 2). A disturbance o r i g i n ( f i r e or wind) of the stands i s suspected because of the even-sized structure of the tree stratum. This community type has s i m i l a r i t i e s to the montane Tsuga-Abies f o r e s t s (A3), which are found on better drained s i t e s , but i n wetter coastal areas (Figs. 9a and b, and 14; Tables 26 and 2 7). The montane Abies-Tsuga f o r e s t s correspond to the Rhytidiadelphus-Oval-leaved & Alaskan Blueberry-Amabilis Fir-Western Hemlock biogeocoe-n o t i c type of the West Vancouver Island Montane Wetter Maritime CWH sub-zone variant (Klinka et a l , , 1979). K l i n k a et a l . (1979) report that Rhytidiopsis robusta, Gaultheria shallon and Vaccinium parvifolium are more common i n stands of d r i e r s i t e s at the upper l i m i t of the va r i a n t , and i n stands situated the fart h e s t inland. Both stands sampled are found at the eastern l i m i t of the subzone vari a n t mentioned. _2----£-^£HE^lAbies_forests (A3) This community type has the lowest mean t o t a l basal area (79.5 m2/ha) within the Abies group (Table 26). The species poor tree stratum consists e n t i r e l y of Tsuga heterophylla and Abies amabilis, with Tsuga  heterophylla showing the most abundant regeneration (Table 26). The 98 sparse and species poor shrub layer i s dominated by Vaccinium parvir: folium. The herb stratum i s equally poor and sparse, with Blechnum  spicant accounting f o r most of the coverage. The bryophyte-lichen layer i s t y p i c a l of the Abies group (Table 27). The montane Tsuga-Abies f o r e s t s are most often found at mid to high elevations near the coast (only once i n the c e n t r a l part of the study area). They occur mostly on upper-slope topographic positions of generally north facing, very strong to steep slopes (Fig. 9b). The deep and well drained s o i l s are mostly formed of c o l l u v i a l material. The organic horizons are thick (average of 15 cm) and contain most of the roots (Appendix 2). The s o i l s are c l a s s i f i e d as Orthic Humo-Ferric Podzols (Table 29). Most stands show evidence of wind disturbance, but only one shows evidence of f i r e . Although t h i s community type i s found at, or near, the w e l l drained crests of mountains nearest to the coast, i t has no s i m i l a r i t i e s with the community types of the Thuja group, found on adjacent lower topographical positions (montane coastal Thuja forests (T3) or coastal Thuja f o r e s t s (T4). This type has some s i m i l a r i t i e s to the more coastal montane Abies-Tsuga f o r e s t s (A2), and to the cooler and wetter montane Abies-Streptopus f o r e s t s (A4) (Figs. 9a and b, and 14; Tables 26 and 27). The montane Tsuga-Abies forests have s i m i l a r i t i e s to the Rhyti- diadelphus-Red Huckleberry & Alaskan Blueberry-Amabilis Fir-Western Hemlock biogeocoenotic type of the West Vancouver Island Submontane Wetter Maritime CWH subzone vari a n t (Klinka et^ a l . , 1979) . K l i n k a et^ a l . (1979) report that the most frequent disturbance i n these communities i s caused by southerly, or westerly, gale force winds. Such disturbance, 99 p a r t i c u l a r l y on exposed upper-slopes and cres t s , i s responsible for the development of nearly even-aged stands of Tsuga-heterophylla and Abies  amabilis (Klinka et_ a l . , 1979). In the Montane Tsuga-Abies f o r e s t s such a structure i s frequently observed, giving the impression of a two-t i e r e d f orest comprising an upper t i e r of mature trees and a lower t i e r of saplings. Montane Abies-Streptopus f o r e s t s (A4) These fo r e s t s have a high mean t o t a l basal area (122 m2/ha) as well as a high mean maximum tree height (53 m (Table 26)). Only Abies  amabilis, the dominant species, and Tsuga heterophylla form the tree stratum. Abies amabilis shows the best regeneration (Table 26). The coverage of the shrub stratum, the poorest i n species within the study area, i s almost e n t i r e l y made up by Vaccinium alaskaense. Oplopanax  horridus i s nearly always present. The herb layer, with the largest coverage and number of species within the Abies group, i s characterised by Rub us pedatus, Streptopus roseus and S_. streptopoides. Several fern species, i n d i c a t i v e of moist and?.-nutrient-rich s o i l s , are present (Adian- tum pedatum, Athyrium f i l i x - f e m i n a and Gymnocarpium dr y o p t e r i s ) . The sparse bryophyte-lichen layer i s c h a r a c t e r i s t i c of the Abies group, except f o r the only occurrence within the study area of Eurhynchium p u l - chellum i n two stands on limestone bedrock (Table 27). This moss i s usually found on calcareous substrata (Schofield, 1976). This community type i s found i n the c e n t r a l part of the study area above 600 m. I t occurs on mid-slope and upper-slope topographic positions 100 of very strong, generally north facing slopes (Fig. 9b). S o i l s are deep, moderately w e l l to imperfectly drained, and have formed from c o l l u v i a l material. The organic horizons are very thick (average of 21 cm) and contain most of the roots (Appendix 2). The s o i l s belong to various types (Table 29), but most are gleyed as a r e s u l t of constant see-page (as the presence of Oplopanax horridus i n d i c a t e s ) . No evidence of f i r e disturbance was found, but wind disturbance was noticed i n the two stands nearest to the ocean. This community type i s environmentally quite d i f f e r e n t from other community types, but i s perhaps clo s e s t to the montane Abies-Tsuga f o r e s t s (A2) or to the montane Tsuga-Abies f o -rests (A3) (Figs. 9a and b, 13 and 14; Tables 26 and 27). The montane Abies-Streptopus f o r e s t s are quite s i m i l a r i n composition to the lowland Abies f o r e s t s (A5), although they occur at t o t a l l y d i f f e r e n t elevations (Fig. 9a and b). The Abies/Vaccinium alaskaense/Streptopus habitat type described fo r eastern Vancouver Island by Beese (1981) corresponds nearly exactly to the Montane Abies-Streptopus f o r e s t s . These fo r e s t s also are s i m i l a r to the Streptopo-Abietum as s o c i a t i o n described by Brooke e^ t aJL. (1970) fo r the Coastal Subalpine Mountain Hemlock Zone. This association i s characterized by constant seepage (Brooke et a l . , 1970). Kojima and K r a j i n a (1975) pointed out the resemblance of the Streptopo-Abietum asso-c i a t i o n with t h e i r Vaccinium alaskaense association situated at lower elevations. In t h i s study area, the Abies-Streptopus f o r e s t s and the lowland Abies f o r e s t s (comparable to the V. alaskaense association) also are f l o r i s t i c a l l y s i m i l a r (Fig. 9a and b; Tables 26 and 27). The Abies  amabilis/Streptopus roseiis a s s o c i a t i o n described by Franklin and Dyrness (1973) f o r the Abies amabilis zone of Washington also i s related. 101 Lowland Abies_forgsts (A5) (Fig. 18f) The lowland Abies f o r e s t s have a low mean t o t a l basal area (107.7 m2/ha) but an excellent mean maximum tree height (54 m) compared to other community types of the Abies group (Table 26). Abies amabilis achieves i t s highest dominance i n the study area (Fig. 18f), and Tsuga  heterophylla i s the second dominant i n a two species tree stratum. Both species are regenerating (Table 26). The moderately developed shrub layer i s made up of Vaccinium alaskaense and V. parvifolium averaging 2 m i n height. The herb stratum i s marked by the abundance of Blechnum  spicant, Dryopteris austriaca and T i a r e l l a t r i f o l i a t a . The well developed bryophyte-lichen stratum, although the r i c h e s t within the Abies group, has no p a r t i c u l a r l y c h a r a c t e r i s t i c species. The lowland Abies f o r e s t s occur throughout the study area, except fo r the co a s t a l p l a i n and the d r i e s t inland areas. They occur at low to mid-elevations, on the lower-slopes or terraces of narrow r i v e r v a l l e y s ; aspects most often are north facing (Fig. 9b). The topographic l o c a t i o n suggests that the s i t e s are subjected to cold a i r drainage ( M i l l e r et a l . , 1983) or snow accumulation (Kojima and K r a j i n a , 1975). The lowland Abies forests are generally found on strong slopes, with deep, moderately well drained s o i l s formed from a v a r i e t y of materials ( c o l l u v i a l , morainal, f l u v i a l ) . The organic horizons are thick (average of 15 cm) and ha l f of the root mass i s found within them (Appendix 2). Evidence of wind d i s -turbance was found i n le s s than half of the stands, and f i r e disturbance was found i n only two stands. This community type shows environmental s i m i l a r i t i e s with the Tsuga-Blechnum-Polystichum f o r e s t s (A7) and the 102 coastal Tsuga-Blechnum-Polystichum f o r e s t s (T2) (Figs. 13 and 14). Vege-t a t i o n a l l y , i t i s most s i m i l a r to the montane Abies-Streptopus f o r e s t s (A4), although t h i s type occurs at a much higher elevation (Figs. 9a and b, 13 and 14; Tables 26 and 27). The. lowland Abies f o r e s t s f i t c l o s e l y the desc r i p t i o n given by Kojima and K r a j i n a (1975) of the Vaccinium alaskaense association found i n Strathcona P r o v i n c i a l Park. These authors i n d i c a t e that most of th e i r stands were found on terraces close to the bottom of protected v a l l e y s , or on the gentle slopes of h i l l s i d e s . They suggest that snow accumulation may explain the presence of t h i s association which usually occurs at higher elevations. In the present study area, stands of the lowland Abies f o r e s t s were found i n very s i m i l a r s i t e s to those described by Kojima and K r a j i n a (1975). On eastern Vancouver Island, the Abies/ Vaccinium alaskaense-V. parvifolium habitat type described by Beese (1981) has s i m i l a r i t i e s with the lowland Abies f o r e s t s . Franklin and Dyrness (1973) report that the c l i m a t i c climax community f o r the Abies amabilis Zone (600-1300 m) of the northern Washington Cascade Range i s an Abies  amabilis/Vaccinium alaskaense association with an abundance of mesic herbs and Rubus pedatus. However, the lowland Abies f o r e s t s described here are not considered zonal plant communities because of the p a r t i c u l a r topographic factors i n f l u e n c i n g t h e i r microclimate. Tsuga-Gaultheria-Blechnum f o r e s t s (A6) This community type has a low mean t o t a l basal area (116.5 m2/ha) and a low mean maximum tree height (46 m), r e l a t i v e to the other types 103 within the Abies group (Table 26). Tsuga heterophylla strongly dominates the tree stratum and i s the major regenerating species. Abies amabilis i s the second dominant, but i s not regenerating abundantly (Table 26). The species poor shrub stratum has a large coverage, dominated by Gaul- t h e r i a shallon (over 1 m high) and Vaccinium parvifolium (2 to 3 m high). The herb layer i s the most species-poor within the study area and i s e n t i r e l y dominated by Blechnum spicant. The bryophyte-lichen stratum, with the highest coverage within the Abies group, i s characterized by an abundance of S t o k e s i e l l a oregana (Table 27). The Tsuga-Gaultheria-Blechnum f o r e s t s were found on the coast and i n the c e n t r a l part of the study area, on low elevation mid-and lower-slope topographic positions (Fig. 9b). The s o i l s are deep, modera-te l y w ell drained, Gleyed Humo-Ferric Podzols formed from morainal mate-r i a l (Table 29). The organic horizons are moderately thick (average of 11.5 cm), and roots are abundant i n the upper mineral horizons (Appen-dix 2). No evidence of f i r e was found, but one stand did show signs of wind disturbance. This community type has environmental s i m i l a r i t i e s with several other community types, (Figs. 13 and 14), but i s r e l a t i -v e l y d i s t i n c t v e g e t a t i o n a l l y , except f o r some s i m i l a r i t i e s with some types of the Thuja group (Fig. 9a; Tables 24, 25, 26 and 27). Tsuga-Blechnum-Polystichum f o r e s t s (A7) (Fig. 18e) This community type has the highest mean t o t a l basal area . (185.2 m2/ha) and the highest mean maximum tree height (64 m) of the Abies group (Table 26). Tsuga heterophylla dominates the tree stratum 104 i n a l l stands and i s the only species regenerating. Pseudotsuga menzie- s i i , Thuja p l i c a t a and Picea s i t c h e n s i s are the second dominants depen-ding on the stand (Table 26). The shrub layer i s the most species-poor within the study area. Dominance of the herb stratum i s shared equally by Blechnum spicant and Polystichum muniturn (Fig. 18e). The bryophyte-l i c h e n layer i s sparse, but generally c h a r a c t e r i s t i c of the Abies group (Table 26). This community type i s found from the coast to the c e n t r a l part of the study area, but i s absent from the dry inland sector. These forests occur on the lower and mid-slope topographic positions of very strong slopes, mostly at low elevations (Fig. 9b). The s o i l s are deep and well to moderately w e l l drained. In most cases s o i l s have formed from morainal material, except those of two coastal stands which have developed from c o l l u v i a l material o r i g i n a t i n g from ancient land s l i d e s . Better drainage on the colluvium may account for the vegetational simi-l a r i t i e s between the co a s t a l and the inland stands of t h i s type. The organic horizons are thick (average of 13 cm) and contain most of the root mass (Appendix 2). Most s o i l s are Orthic Humo-Ferric Podzols; also represented are a Gleyed Humo-Ferric Podzol and a Gleyed Ferro-Humic Podzol (Table 29). Evidence of f i r e disturbance was found i n two of the c e n t r a l stands, and land s l i d e s were at the o r i g i n of the two coastal stands. This community type i s most s i m i l a r to the coastal Tsuga- Blechnum-Polystichum forests (T2) (Fig. 14; Tables 24, 25, 26 and 27). The d i f f e r e n c e i s mostly one of geographical l o c a t i o n , r e s u l t i n g i n a wetter s o i l moisture regime f o r the coastal type because of higher amounts of p r e c i p i t a t i o n . This i s r e f l e c t e d by a l e s s e r amount of Pseudotsuga 105 menziesii and Polystichum muniturn, and a higher amount of Abies amabilis and Blechnum spicant i n the coastal Tsuga-Blechnum-Polystichum fo r e s t s (T2), than i n the Tsuga-Blechnum-Polystichum f o r e s t s . The Tsuga-Blechnum-Polystichum fo r e s t s are very s i m i l a r to the better drained and most productive stands of the Rhytidiadelphus-Red Huckleberry & Alaskan Blueberry-Amabilis Fir-Western Hemlock biogeo-coenotic type within the West Vancouver Island Submontane Wetter Maritime CWH Subzone varia n t (Klinka et^ aJ.. , 1979) ; however the Tsuga-Blechnum- Polystichum f o r e s t s described here probably have a d r i e r s o i l moisture regime as indicated by the predominance of Tsuga heterophylla and Pseudo- tsuga menziesii over Abies amabilis (Table 26). 106 5. FLOODPLAIN VEGETATION GROUP ^i^S^EiS^-^SE^^^S (^1) Floodplain f o r e s t s possess the largest mean t o t a l basal area i n the study area (246.2 m 2/ha), as well as a high mean maximum tree height (60 m (Table 24)). The dominant tree i s most often Picea s i t c h e n s i s , but Thuj a p l i c a t a and even Pseudotsuga menziesii dominate i n some of the plots. Tsuga heterophylla i s , on average, the second dominant and i s the only species regenerating well (Table 24). Rubus s p e c t a b i l i s , Ribes  bracteosum and Vaccinium species often form a continuous shrub layer over 2 m i n height. The herb stratum, the r i c h e s t i n the study area, i s dominated by Polystichum muniturn and Athyrium f i l i x - f e m i n a which form a continuous, one metre high layer i n some stands. Many herb species such as T r a u t v e t t e r i a c a r o l i n i e n s i s , Melica subulata, Luzula p a r v i f l o r a and Aruncus Sylvester are r e s t r i c t e d to t h i s community type. Leucolepis  menziesii, Plagiomnium insigne and S t o k e s i e l l a praelonga characterize the bryophyte-lichen stratum (Table 25). This community type i s found at low elevations throughout the study area on the floodplains of major r i v e r s . The shrub stratum i s often absent or weakly developed i n younger stands, or stands situated on the most a c t i v e f l o o d p l a i n s . In contrast, such stands have a well developed herb stratum with up to 85 % coverage of Polystichum munitum. Older stands, or stands on.less a c t i v e f l o o d p l a i n s , have a dense shrub layer (mainly Rubus s p e c t a b i l i s ) and usually have a few very large Picea  s i t c h e n s i s . The s o i l s are deep, w e l l drained loams of a l l u v i a l or f l u -v i a l nature and contain very few coarse fragments; the organic horizons 107 are t h i n and tree roots penetrate deeply into the mineral s o i l (Appen-dix 2). The water table was not encountered i n any of the s o i l p i t s ; however, the s o i l s remain moist owing to t h e i r f i n e texture and the l e v e l t e r r a i n . The s o i l s are mostly Gleyed Sombric Brunisols (Table 29). Signs of wind disturbance, mostly i n the form of uprooted large Picea  s i t c h e n s i s , were found i n h a l f of the stands; a few stands contained evidence of f i r e . Floodplain forests have few s i m i l a r i t i e s to other types described for the study area. Their closest a f f i n i t y i s with the Thuja group (Figs. 5, 13 and 14; Tables 24 and 25). Floodplain forests correspond c l o s e l y i n vegetation composition and e c o l o g i c a l c h a r a c t e r i s t i c s to the Picea sitchensis-Polystichum  munitum-Leucolepis menziesii f o r e s t type described by Cordes (1972) for floodplains of the west coast of Vancouver Island. F i r s t and second r i v e r terrace communities described by Fonda (1974) for the Olympic National Park, Washington State, also have s i m i l a r i t i e s with the f l o o d p l a i n f o r e s t s . The former d i f f e r from the l a t t e r by having a lesser coverage of Rubus  s p e c t a b i l i s (probably because of elk browsing) and an abundance of Oxalis  oregana i n the understory. Phytogeographically, the Picea s i t c h e n s i s dominated f l o o d p l a i n forests range along the coast from southern Alaska to southern Oregon where they merge with the Redwood forests (Fonda, 1974). Oxalis oregana i s a c h a r a c t e r i s t i c element of these forests i n Washington, Oregon, and C a l i f o r n i a , but i t was found only near the Klanawa River (plots 170 et 171) within the study area. The phytogeography of t h i s species i n B r i t i s h Columbia has recently been discussed by O g i l v i e e_t a l . (1984). 108 Floodplain forests (Lysichitum variant) (F2) This community type has a structure s i m i l a r to the t y p i c a l f l o o d -p l a i n f o r e s t s (Fl) , with a very large mean t o t a l basal area (236.5 m2/ha) and a high mean tree height (56 m (Table 24)). Picea s i t c h e n s i s and Thuja p l i c a t a share dominance equally. Tsuga heterophylla i s the t h i r d dominant and i s the only species regenerating well (Table 24). The dense and almost continuous shrub stratum (over 3 m high) i s dominated by Gaultheria shallon, Rubus s p e c t a b i l i s and Vaccinium species. The high coverage herb layer i s dominated nearly equally by Blechnum spicant, Lysichitum americanum and Polystichum muniturn. The bryophyte-lichen stratum i s s i m i l a r i n composition to that of the t y p i c a l f l o o d p l a i n forests (Fl) . The Lysichitum variant of the f l o o d p l a i n f o r e s t s was found i n only one area near the coast, on the a l l u v i a l p l a i n of a small r i v e r . The s o i l s are very poorly drained Humic Gleysols formed from a l l u v i a l deposits (Table 29). The organic horizons are t h i n , and the e f f e c t i v e rooting depth (averaging 80 cm) i s r e s t r i c t e d by a shallow water table (Appendix 2). Evidence of f i r e and wind disturbance was found. Apart from the poorer drainage and heavier s o i l texture, t h i s community type i s s i m i l a r to the t y p i c a l f l o o d p l a i n f o r e s t s (Figs. 5 and 14; Tables 24 and 25). The Lysichitum v a r i a n t of the fl o o d p l a i n f o r e s t s i s very s i m i l a r , f l o r i s t i c a l l y and e c o l o g i c a l l y , to the Picea sitchensis-Lysichitum ame- ricanum f o r e s t type described by Cordes (1972) f o r the west coast of Vancouver Island. 109 6. SUBALPINE VEGETATION GROUP ( SA) The subalpine vegetation group i s formed by an heterogeneous assemblage of eleven plots ranging i n elevation from 485 m to 1050 m (mean = 789 m). Most plots of t h i s group probably represent low e l e -vation extensions of vegetation types more common above the upper elevation l i m i t set for t h i s study; therefore, the desc r i p t i o n of t h i s group i s general. Tsuga heterophylla dominates the tree stratum; Abies amabilis i s the second dominant and also i s the most abundantly regenerating species (Table 28). Tsuga mertensiana and Chamaecyparis nootkatensis also are important i n the tree stratum. Both of these species are c h a r a c t e r i s t i c of high elevation coastal f o r e s t s (Krajina, 1969; Brooke et a l . , 1970; Klinka et a l . , 1979). Pseudotsuga menziesii i s r e l a t i v e l y abundant i n many stands, presumably because of past f i r e disturbance. A general pattern also can, be described f o r the understory s t r a t a . Most stands have a shrub layer strongly dominated by Vaccinium alaskaense (up to 50 % coverage). The herb stratum i s generally sparse and i s characte-r i z e d by species such as C l i n t o n i a u n i f o l i a , Rubus pedatus, T i a r e l l a u n i - f o l i a and Veratrum v i r i d e . The bryophyte-lichen layer i s usually well developed, with t o t a l coverages of up to 75 %, and i s always strongly dominated by Rhytidiopsis robusta. Other species, such as Vaccinium  memb ran a c eum, Gaultheria o v a t i f o l i a , Phyllodoce empetriformis and V i o l a  o r b i c u l a t a , were found most often within t h i s group. Rhododendron a l b i - florum and F r i t i l l a r i a camschatcensis were found only i n plots of the subalpine vegetation group. 110 The environmental conditions (mainly the s o i l moisture and nu-t r i e n t status) appear to vary widely i n t h i s group (Appendix 2). Asso-c i a t i o n s within the subalpine Mountain Hemlock Zone of coastal B r i t i s h Columbia have been described by Brooke et a l . (1970). Klinka et a l . (1979) describe eastern and western variants within a Maritime Forested Mountain Hemlock biogeoclimatic subzone f o r Vancouver Island. Fonda and B l i s s (1969) discuss an Abies amabilis-Tsuga mertensiana community type fo r the Olympic Mountains of Washington. Franklin and Dyrness (1973) also discuss the communities of the Tsuga mertensiana Zone of the P a c i f i c Northwest States. I l l D. VEGETATION STRATA HOMOGENEITY AND SPECIES RICHNESS WITHIN TYPES The average homogeneity c o e f f i c i e n t s and the average species richness values of vegetation s t r a t a i n fourteen community types are summarized i n Table 31. The seedling stratum, followed c l o s e l y by the tree and sapling s t r a t a , are, on average over a l l types, the most homo-geneous i n the study area. Most community types are composed of o l d -growth stands with closed canopies where seedling establishment i s r e s t r i c t e d almost e n t i r e l y to a few shade tolerant species; thus, a high degree of uniformity within the seedling stratum i s to be expected. Com-munity types with open canopies, such as the dry Pinus-Pseudotsuga forests (DI), the coastal dry Pinus f o r e s t s (D2), and some stands within the Floodplain f o r e s t s (Fl) show a much lower homogeneity i n t h e i r seedling s t r a t a . The lower homogeneity of the tree stratum may r e f l e c t v a r i a t i o n i n the type and i n t e n s i t y of disturbances at the o r i g i n of the stands. The tree stratum often contains large proportions of l o n g - l i v e d , shade int o l e r a n t species (eg. Pseudotsuga menziesii) which are usually absent i n seedling s t r a t a . The shrub stratum i s le s s homogeneous than the tree, sapling, and seedling s t r a t a , but i s , on average, more homogeneous than the herb and bryophyte-lichen layers (Table 31). The coastal wet Thuja f o r e s t s (T5) have the most homogeneous and one of the most s p e c i e s - r i c h shrub s t r a t a . The l e a s t homogeneous shrub stratum i s found i n the Floodplain forests (Fl) and may r e f l e c t v a r i a t i o n s i n flooding regime or stand age (see Chapter 4. C, section 5). 112 The most homogeneous herb s t r a t a occur i n the Thuja group commu-n i t y types, because of the strong dominance of Blechnum spicant growing profusely on the thick organic horizons to the exclusion of nearly a l l other herbs. The le a s t homogeneous herb s t r a t a are found i n the montane Tsuga f o r e s t s (P6) and the montane Tsuga-Gaultheria f o r e s t s (P7). The herb s t r a t a of these two types (P6 and P7) have very low t o t a l coverages and, although average species richness i s low, the t o t a l number of spe-cies encountered i s r e l a t i v e l y high (Table 23), r e s u l t i n g i n herb stratum heterogeneity within the types. The bryophyte-lichen layer i s o v e r a l l the le a s t homogeneous of a l l the vegetation s t r a t a , possibly because i t r e f l e c t s varying micro-s i t e conditions from stand to stand (microtopography, number of f a l l e n logs, area of bare rock surfaces, e t c . ) . The average homogeneities of community types over a l l s t r a t a are also shown i n Table 31. The coastal Thuja f o r e s t s (T4) and the coastal wet Thuja f o r e s t s (T5) have the most homogeneous vegetation; the Flood-p l a i n f o r e s t s (Fl) have the l e a s t homogeneous vegetation. Thuja types T4 and T5 occur at low elevation very near to the coast where the climate and other environmental conditions are more uniform (no dry summer period, no f r e e z i n g , abundant seepage, thick organic layers, e t c . ) , and where f i r e disturbances are unusual (see f i r e index f o r Thuja types i n Table 31) and wind disturbances not as frequent as at high elevations. The combi-nation of these factors may be responsible f o r the extremely homogeneous vegetation. By contrast, numerous tree species can grow very success-f u l l y on floodplains where nutrients and moisture are abundant. The 113 establishment of seedlings following a major disturbance on a f l o o d p l a i n i s probably mostly a r e s u l t of stochastic events and proximity of seed sources, rather than environmental f a c t o r s , leading to the lack of homogeneity in the tree stratum. Further heterogeneity i s introduced by the flooding regime which may favor or hinder the development of a p a r t i c u l a r under-story species or stratum. There does not appear to be a cl e a r , general r e l a t i o n s h i p between the mean richness of a stratum and i t s homogeneity. The shrub layer tends to be s l i g h t l y more homogeneous with increasing richness (r = .349), but the herb layer tends to be s l i g h t l y l e s s homogeneous with increasing richness (r = -.349). Herb and shrub layers also tend to be les s homo-geneous with increasing f i r e index values (herbs, r =-.589; shrubs, r = -.425), while the tree stratum tends to be more homogeneous (r = .358). The i n t e r p r e t a t i o n of the f i r e index values i s l i m i t e d because they do not include information on f i r e i n t e n s i t y or frequency. The f i r e index values do in d i c a t e that f i r e s have occurred predominantly i n dry Pinus- Pseudotsuga f o r e s t s (Dl) and i n a l l Pseudotsuga types (P3 to P7. i n table 31). F i r e may be said to be a rare occurrence i n types where the f i r e index value i s smaller than i t s standard deviation (an estimate of the v a r i a b i l i t y ) . 114 E. TREE SIZE-CLASS STRUCTURE OF COMMUNITY TYPES The s i z e - c l a s s d i s t r i b u t i o n s of tree species can o f f e r some in s i g h t into community dynamics so long as c e r t a i n l i m i t a t i o n s of t h i s approach are borne i n mind (Harper, 1977). Individuals of a s i n g l e tree species which become established on a s i t e following a disturbance usually w i l l not have the same s i z e , even when the time of establishment i s i d e n t i c a l . Within s i t e differences i n n u t r i e n t or water a v a i l a b i l i t y , and presence of competing neighbours may cause s i z e differences between trees of i d e n t i c a l age. In addition, the establishment of trees following a disturbance i s often spread over several years, during which time con-d i t i o n s of resource a v a i l a b i l i t y and competition may also vary. For these reasons, even t y p i c a l l y s e r a i species w i l l show a wide range of sizes (although a peak number of stems i s usually found i n one s i z e - c l a s s ) i n stands that owe t h e i r o r i g i n to a s i n g l e disturbance i n the past. This e f f e c t i s amplified here because data from several p l o t s were compiled for each community type; thus apart from the l i k e l y environmental d i f f e -rences between p l o t s , the time and i n t e n s i t y of the disturbance also may vary. Nevertheless, the graphs (Figs. 15-17) do i l l u s t r a t e differences i n s i z e c l a s s structure between s e r a i tree species, whose presence r e s u l t s from; past disturbance, and shade tolerant species, whose regeneration i s not s t r i c t l y linked to disturbance. Shade tolerant or "climax" species, w i l l be r e f e r r e d to as "primary" species i n the terminology of Brokaw (1980). Stem numbers i n the s i z e - c l a s s d i s t r i b u t i o n figures (Figs. 15, 16 and 17) are on a logarithmic scale. I t i s noted that the c l a s s i c a l , rever-sed "J"-shaped curve remains c h a r a c t e r i s t i c of primary species, while a be shaped d i s t r i b u t i o n of sizes i s associated with s e r a i or pioneer species. 115 1. PSEUDOTSUGA TYPES The s i z e - c l a s s d i s t r i b u t i o n curves of major tree species i n d i f f e r e n t community types of the Pseudotsuga group are generally s i m i l a r (Fig. 15). Pseudotsuga menziesii, with most of i t s stems i n the larger s i z e - c l a s s e s , i s c h a r a c t e r i s t i c of a s e r a i species; however, t h i s trend i s l e s s obvious i n community types r e s t r i c t e d to the d r i e s t , low e l e -vation, inland part of the study area (types DI, PI, P2 and P3). Only in the dry Pinus-Pseudotsuga forests (DI), on rock outcrops, does the s i z e - c l a s s d i s t r i b u t i o n of Pseudotsuga menziesii appear c h a r a c t e r i s t i c of a primary species. In a l l types where they are important, Tsuga  heterophylla and Thuja p l i c a t a have s i z e - c l a s s d i s t r i b u t i o n s characte-r i s t i c of primary species. In community types with progressively greater s o i l moisture supply (types P3 to P5, and the higher elevation type P6), Tsuga heterophylla i s in c r e a s i n g l y found i n larger s i z e - c l a s s e s . In the montane Tsuga f o r e s t s (P6), the s i z e - c l a s s containing most Pseudotsuga  menziesii stems also contains an equivalent number of Tsuga heterophylla stems. This contrasts with the d r i e r , lower elevation Pseudotsuga- Berberis f o r e s t s (P4), where the s i z e - c l a s s with the most Pseudotsuga  menziesii stems has very few Tsuga heterophylla stems (Fig. 15). This diff e r e n c e could be caused by a cooler and wetter climate at higher eleva-tions allowing Tsuga heterophylla to grow as r a p i d l y as Pseudotsuga men- z i e s i i a f t e r a disturbance. Double peaks can be seen i n the s i z e - c l a s s d i s t r i b u t i o n curves of Pseudotsuga menziesii i n types P2 and P7. Because the plots of the Pseudotsuga-Thuj a-Acer f o r e s t s (P2) are very s i m i l a r environmentally (Appendix 2) and are s p a t i a l l y close (within a 2 km 116 radius of the Dog Mountain peninsula on Sproat Lake, F i g . 1), i t i s proposed that the two peaks correspond to two d i s t i n c t f i r e disturbances i n the past. The largest Pseudotsuga menziesii trees a l l have f i r e charred bark. The double Pseudotsuga menziesii peaks i n type P7 cannot be i n t e r -preted s i m i l a r l y with equal confidence since the p l o t s are scattered s p a t i a l l y . 117 2. THUJA TYPES Pinus contorta, i n the coastal wet Thuja f o r e s t s (T5), i s the only example of a s e r a i species s i z e - c l a s s d i s t r i b u t i o n within the Thuja group (Fig. 16). In the coastal dry Pinus forests (D2) Pinus contorta appears to be a primary species. Abies amabilis, Tsuga heterophylla, and Thuja  p l i c a t a a l l have s i z e - c l a s s d i s t r i b u t i o n s c h a r a c t e r i s t i c of primary species (Fig. 16). In the coastal montane Thuja f o r e s t s (T3) and the coastal Thuja f o r e s t s (T4), the curves f o r Thuja p l i c a t a are strongly skewed toward the larger s i z e - c l a s s e s (Fig. 16). This p a r t i c u l a r s i z e -class d i s t r i b u t i o n may r e f l e c t the very large sizes attained by Thuja  p l i c a t a as w e l l as i t s impressive longevity of approximately 1000 years, which i s twice that of Tsuga heterophylla and Abies amabilis (Waring and Franklin, 1979). Thuja p l i c a t a also shows low m o r t a l i t y when mature because of i t s high resistance to fungal and insect attack (Minore, 1979). 118 3. ABIES TYPES In most of the community types presented i n F i g . 17, Abies ama- b i l i s and Tsuga heterophylla are considered primary species able to regenerate i n the understory; however, wind disturbance may cause the occasional p u l s e - l i k e establishment of trees, indicated by peaks i n the larger s i z e - c l a s s e s of some community types (A3, A4, A5 and T2). Abies amabilis presents a s i z e - c l a s s d i s t r i b u t i o n curve charac-t e r i s t i c of a primary species i n the A l , A4,and A5 community types. Tsuga heterophylla may also be considered a primary species i n the A l , A7, and T2 types; however i t s d i s t r i b u t i o n curves have peaks i n the larger s i z e - c l a s s e s of the A3, A4 and A5 types, suggesting that d i s t u r -bance may p a r t l y explain i t s presence i n these types. The montane Tsuga-Abies f o r e s t s (A3), situated on upper mountain slopes and ridges near the coast, are p a r t i c u l a r l y susceptible to wind disturbance causing p a r t i a l or t o t a l blowdowns. Stands of t h i s community type have been observed i n various stages of recovery following wind disturbance. A two-ti e r e d structure caused" by wind disturbance i n coastal mountain Abies  amabilis and Tsuga heterophylla f o r e s t s has been described by Kl i n k a et a l . (1979). The upper layer consists of mostly even-sized, dominant trees; numerous small trees and saplings characterize the understory. Pseu- dotsuga menziesii's s i z e - c l a s s d i s t r i b u t i o n curve i n the montane Tsuga- Abies-Gaultheria forests (Al) i s c h a r a c t e r i s t i c a l l y s e r a i (Fig. 17). 119 F. TREE SEEDLING ABUNDANCE ON UNDECOMPOSED WOOD AND FOREST FLOOR SUBSTRATA The abundance patterns of seedlings of the major tree species on undecomposed wood and forest f l o o r substrata vary greatly within the study area (Table 32). The abundance of Tsuga heterophylla seedlings on undecomposed wood i s almost always s i g n i f i c a n t l y higher than on the for e s t f l o o r i n the community types studied (Table 32). In community types of the Thuja group, Thuja p l i c a t a seedlings are always s i g n i f i -cantly more abundant on undecomposed wood (Table 32); however, i n the d r i e r , inland types (P4 and P6), Thuja p l i c a t a seedlings, although of low d e n s i t i e s , are equally abundant on both substratum classes (Table 32). Abies amabilis seedlings are, i n general, equally abundant on undecomposed wood and fo r e s t f l o o r substrata. Pseudotsuga menziesii seedlings occur i n equal amounts on both substratum classes i n the two community types (P4 and P6) where there were s u f f i c i e n t data f o r ana-l y s i s (Table 32). Pseudotsuga menziesii i s a lon g - l i v e d , s e r a i species in these closed canopy, old-growth f o r e s t s , and i s absent from the sapling s i z e - c l a s s (Fig. 15). Seedling establishment conditions f o r th i s shade-intolerant species are poor, as r e f l e c t e d by low seedling de n s i t i e s (Table 32). Patterns of Pseudotsuga menziesii seedling abun-dance on organic or mineral s o i l substrata are l i k e l y to be d i f f e r e n t i n a more open environment following a fo r e s t f i r e . 120 CHAPTER 5 DISCUSSION A. VEGETATION ANALYSIS 1. GENERAL VEGETATION PATTERNS The i n t e r p r e t a t i o n of the 172 and 140 plots ordinations (Figs. 5 and 6) supports the f i r s t two hypotheses formulated i n the Introduction. These hypotheses proposed that, i n order of decreasing importance, macro-c l i m a t i c and s o i l parent material factors would c o r r e l a t e most strongly with the vegetation patterns. In the 172 p l o t s ordination, an elevation macro-climatic gradient i s r e f l e c t e d i n the vegetation pattern expressed along the f i r s t and second axes (Fig. 5), leading to the i s o l a t i o n of a group of subalpine vegetation p l o t s . Low elevation p l o t s , belonging to the f l o o d p l a i n vegetation group and the Pinus contorta vegetation group of rock outcrops, also are i s o l a t e d on the f i r s t axis of t h i s ordination, r e f l e c t i n g a s o i l parent material gradient, secondary i n importance to the macro-climatic gradient which i s r e f l e c t e d on two axes (Fig. 5). The highest elevations represent the cooler end of the macro-c l i m a t i c gradient, where continuous snow accumulation occurs during winter months. This, i n turn, has a marked e f f e c t on organic horizons structure, and on tree seedling establishment and s u r v i v a l (Brooke et a l . , 1970; Klinka et a l . , 1979). Abies amabilis seedlings are reportedly superior to Tsuga heterophylla seedlings at r e s i s t i n g mechanical damage caused by l i t t e r debris accumulating i n winter snow packs (Thornburg, 1969). 121 The larger s i z e of the Abies amabilis seedling (Schopmeyer, 1974) i s probably very important i n t h i s aspect. Abies amabilis i s undoubtedly regenerating the most suc c e s s f u l l y of a l l the tree species within the subalpine vegetation group (Table 28). The parent material gradient separating the f l o o d p l a i n vegetation group from the Pinus contorta group contrasts the droughty, nutrient poor r e s i d u a l s o i l s of rock outcrops, against the moist, nutrient r i c h a l l u v i a l s o i l s of f l o o d p l a i n s . Species such as Pinus contorta, Arbutus  menziesii, Rhacomitrium lanuginosum and Vaccinium ovaturn characterize the rock outcrops (Table 3), and are e i t h e r tolerant of drought and poor s o i l nutrient conditions, or they are shade i n t o l e r a n t (Minore, 1979). Arbutus  menziesii and Arctostaphylos columbiana are found only on the dry and hot microclimates of rock outcrops near the northern boundaries of t h e i r ranges. Rock outcrops of the i n t e r i o r of the study area also represent the only habitats where Pseudotsuga menziesii regenerates within the study area (Table 22). The c h a r a c t e r i s t i c species of f l o o d p l a i n s , such as Picea s i t c h e n s i s , Rubus s p e c t a b i l i s , Ribes bracteosum, Polystichum muniturn and T r a u t v e t t e r i a  c a r o l i n e n s i s , l i k e l y have high edaphic requirements, such as abundant moisture and high s o i l n utrient l e v e l s , combined with good drainage. Polystichum muniturn probably requires r e l a t i v e l y high l e v e l s of s o i l n utrients based on the high potassium (2 %) content of i t s leaves (Klinka, 1974). Rubus s p e c t a b i l i s and Ribes bracteosum, along with other f l o o d p l a i n species such as Adenocaulon b i c o l o r , Athyrium f i l i x - f e m i n a and Melica  subulata (Table 25) are known as " n i t r a t e accumulators" from the e a s i l y 122 detectable n i t r a t e s i n t h e i r leaves (Krajina et_ al_. , 1982, p. 57). Picea  s i t c h e n s i s i s also beleived to require r e l a t i v e l y high s o i l n utrient l e v e l s (Krajina et a l . , 1982; Minore, 1979). The Pseudotsuga, Thuja and Abies vegetation groups were d i f f e r e n -t i a t e d within an ordination of 140 p l o t s a f t e r the removal of p l o t s from previously i d e n t i f i e d groups (Fig. 6). Strong c o r r e l a t i o n s with distance from the coast, on both the f i r s t and second axes (Table 6), i n d i c a t e that a macro-climatic gradient i s again linked to the vegetation patterns expressed i n t h i s ordination. Plots of the Pseudotsuga group are found i n the part of the study area fa r t h e s t from the coast, while p l o t s of the Thuja group are found only near the coast. Coastal areas receive 50 % more annual p r e c i p i t a t i o n than the Port A l b e r n i surroundings (Fig. 2). The e f f e c t of t h i s steep r a i n f a l l gradient on the vegetation i s explored further i n section 6 (The c l i m a t i c master gradient). Plots of the Abies group do not have p a r t i c u l a r geographical a f f i n i t i e s , and although a few are intermediate i n geographical l o c a t i o n between p l o t s of the Pseudotsuga and Thuja groups, most are associated with high elevations or otherwise m i c r o - c l i m a t i c a l l y cooler s i t e s , such as the bottom of steep-walled v a l l e y s subjected to cold a i r drainage or delayed snowmelt, or to the base of steep north-facing slopes (Fig. 9b). A canonical analysis of the s i x vegetation groups reveals a c l e a r separation of the groups based on environmental data (Fig. 13). However, the f l o o d p l a i n group, the Pinus contorta group and the subalpine group are not as w e l l separated as i n the r e c i p r o c a l averaging vegetation o r d i -nation (Fig. 5). This i s probably r e s u l t s from the abundance of edaphic variables and the lack of d i r e c t c l i m a t i c v a r i a b l e s i n the environmental 123 data matrix used i n the canonical analysis (Table 1). In t h i s case, the ordination based on vegetation data i s believed to r e f l e c t r e l a t i o n s h i p s more accurately (Fig. 5). Predictably, the canonical analysis reveals that the vegetation group most environmentally s i m i l a r to the subalpine group i s the Abies group (Table 16). Within the three larger vegetation groups, the Pseudotsuga and Thuja groups are the l e a s t environmentally s i m i l a r (Table 16). Important macro-climatic differences between coastal areas (Thuja group) and more inland areas (Pseudotsuga group) are r e f l e c t e d i n these r e s u l t s based on non-climatic v a r i a b l e s . Several edaphic v a r i a b l e s , such as organic horizons thickness, rooting c h a r a c t e r i s t i c s , percent carbon and nitrogen i n B horizons, and type of disturbance vary along the distance from the coast gradient (Table 6), and are d i r e c t l y or i n d i r e c t l y r e l a t e d to climate. A gradual change occurs from a f i r e domi-nated disturbance regime inland, towards the coast where f i r e i s v i r t u a l l y absent and the main disturbance factor i s wind. In several p l o t s of the Thuja group, windthrow of a few i n d i v i d u a l trees was the most frequently observed disturbance, although a few large scale wind disturbances were seen (e.g. p l o t s 72 and 151). A l l of the dominant tree species i n the Thuja group, such as Thuja p l i c a t a , Tsuga heterophylla and Abies amabilis are c h a r a c t e r i s t i c a l l y shallow rooting (Minore, 1979); conversely, Pseudo- tsuga menziesii i s a deep rooting species (Minore, 1979). The root d i s t r i -bution recorded i n s o i l p r o f i l e s (Appendix 2) r e f l e c t s f o r e s t composition, which i s linked i n turn to disturbance type, and both are r e l a t e d to climate. The shallow rooting habit of trees near the coast, where the strongest winds occur, may increase the incidence of windthrow. Thuja  p l i c a t a , the dominant tree species i n f o r e s t s near the coast, i s regarded 124 as being more wind-resistant than Abies amabilis and Tsuga heterophylla (Minore, 1979). Pseudotsuga menziesii, the dominant tree species inland, i s considered the most f i r e r e s i s t a n t of the coastal tree species, and Thuja p l i c a t a the l e a s t (Minore, 1979). Some community types within the Abies group, such as the montane Abies-Streptopusforests (A4) and the lowland Abies forests (A5), show l i t t l e disturbance by either f i r e or wind. Montane Abies-Streptopus f o r e s t s (A4) occur on steep, but moist, high elevation s i t e s away from the coast, where strong winds and forest f i r e s are infrequent. The montane Tsuga-Abies forests (A3), however, are situated i n r e l a t i v e l y high e l e v a t i o n s i t e s near the coast and show abundant windthrow. S o i l organic matter accumulation i s greatest i n forests near the coast, where plant production i s nearly continuous owing to the mild climate and p l e n t i f u l s o i l moisture (Valentine, 1971). Nutrient c y c l i n g may occur predominantly i n the thick H horizon of these forests through the intermediary of a recently discovered indigenous earthworm (Spiers et a l . , 1984). This phenomenon seems c l o s e l y linked to the presence of most of the tree root mass within the organic horizons of these f o r e s t s (Spiers e_t a l . , 1984). Thuj a p l i c a t a roots are apparently more numerous i n organic laye r s , when these are thick, than i n the underlying s o i l (Ross, 1932). Percent carbon i s also higher i n the mineral horizons of stands clos e s t to the coast. This r e f l e c t s a c l i m a t i c a l l y c o n t r o l l e d s o i l gradient from a predominance of Humo-Ferric Podzols inland to a predo-minance of Ferro-Humic Podzols near the coast (Jungen and Lewis, 1978). 125 Other environmental v a r i a b l e s , such as elevation, percent slope and drainage q u a l i t y decrease towards the coast, and parent material i s more frequently morainal than c o l l u v i a l (Table 6). These environmental factors are l i k e l y associated with changing topography and not re l a t e d to climate. An exception might be drainage, because i t i s p a r t i a l l y defined on annual duration of s o i l saturation (correlated with amount of s o i l mottling), which could be d i f f e r e n t for i d e n t i c a l s i t e s depending on the t o t a l amount of p r e c i p i t a t i o n and evapotranspiration. Morainal s u r f i c i a l material, predominant near the coast, has slower drainage than c o l l u v i a l material, prevalent inland. 126 2. THE PSEUDOTSUGA GROUP Within the area where p l o t s of the Pseudotsuga group are found, macro-climate and s o i l parent material are f a i r l y homogeneous. The environmental factors most c l o s e l y associated with vegetation patterns appear to be at the scale of meso-climate and s o i l moisture (Figs. 7a and b, Table 8). These observations support hypotheses Ic and Id formulated i n the Introduction. Meso-climate and s o i l moisture have been found repeatedly to play a major r o l e i n the d i s t r i b u t i o n of vege-t a t i o n i n mountainous areas when macro-climate and parent material were uniform (Whittaker, 1956; 1960; Whittaker and Niering, 1965). The d i r e c t ordination of the Pseudotsuga group shows a clear r e l a t i o n s h i p between vegetation patterns and elev a t i o n (= meso-climate) and topographic-moisture gradients (Fig. 7b). Low elev a t i o n s i t e s with abundant s o i l moisture, often at the base of mountain slopes, are most frequently occupied by Tsuga-Pseudotsuga-Polystichum forests (P5). Dry s i t e s at higher elevations (500-800 m), such as c r e s t s , ridges and steep upper-slopes, are occupied by the montane Tsuga-Gaultheria forests (P7). On s i t e s of intermediate moisture regime, an a l t i t u d i n a l gradient can be followed through the low elevation, warmest Pseudotsuga-Thuja-Acer forests (P2), to the mid-elevation Pseudotsuga-Berberis forests (PA), and to the cooler montane Tsuga forests (P6) (Fig. 7a and b). Dry Pseudotsuga forests (PI), Pseudotsuga-Linnaea forests (P3) and Pseudotsuga-Thuja-Acer forests (P2) are c l e a r l y d i f f e r e n t i a t e d v e g e t a t i o n a l l y ( F ig. 7a, Tables 22 and 23) but appear s i m i l a r environ-mentally i n the canonical analyses (Figs. 13 and 14). This discrepancy 127 may be explained by a combination of f i r e disturbance and s o i l moisture d i f f e r e n c e s , unaccounted for by the environmental variables used i n the canonical analyses, but nevertheless r e f l e c t e d by the vegetation. The dry Pseudotsuga forests (PI), because of the almost exclusive presence of large, scattered Pseudotsuga menziesii trees with charred bark, appear to have had the most recent f i r e s . Pseudotsuga-Thuja-Acer f o r e s t s (P2) appear to be environmentally very s i m i l a r to the Pseudotsuga-Linnaea forests (P3) according to the canonical analysis r e s u l t s (Table 17). However, these two community types are d i s t i n c t l y separated on the ordination based on vegetation data ( F i g . 7a). The Pseudotsuga-Linnaea forests (P3) contain numerous species associated with dry s i t e s , such as Gaultheria shallon and Linnaea b o r e a l i s , whereas the Pseudotsuga-Thuja- Acer forests (P2) have a higher abundance of species more c h a r a c t e r i s t i c of mesic habitats, such as Polystichum muniturn and T i a r e l l a t r i f o l i a t a (Table 23). Increased s o i l moisture, through seepage, i s probably respon-s i b l e for the observed vegetational differences between the two community types, although f i r e h i s t o r y also may be important. The environmental variables recorded (Table 1) do not measure s o i l seepage and would contribute l i t t l e to the d i f f e r e n t i a t i o n of the two community types i n the canonical analyses (Figs. 13 and 14). Also, only the occurrence of forest f i r e was recorded, and not i t s i n t e n s i t y or actual date of occur-rence . The dry Pinus-Pseudotsuga forests (Dl) form the dry end of the s o i l moisture gradient on low elevation rock outcrops (Fig. 7b). 128 Environmentally, the two most d i s s i m i l a r community types of the Pseudotsuga group are the Pseudotsuga-Thuja-Acer forests (P2) and the Tsuga-Pseudotsuga-Polystichum forests (P5) (Table 17). The environmental v a r i a b l e s most strongly correlated with t h i s d i f f e r e n c e are topographical p o s i t i o n , maximum s o i l depth and LFH pH (Table 21). The higher s o i l moisture conditions associated with lower-slopes and l e v e l topography, as well as deep s o i l s , are c h a r a c t e r i s t i c of the Tsuga-Pseudotsuga- Polystichum forests (P5). Polystichum munitum i s a dominant understory component i n these f o r e s t s , and Tsuga heterophylla i s regenerating abund-antly (Tables 7, 22 and 23). The Pseudotsuga-Thuja-Acer forests (P2) are found only i n the warmest and d r i e s t sector of the study area, and are characterized by a r e l a t i v e abundance of Thuja p l i c a t a , Cornus n u t t a l l i i and Acer macrophyllum (Tables 7 and 22). The abundance of these tree species appears linked to s o i l seepage conditions. The higher pH of the organic layer of these forests probably can be explained by the calcium r i c h l i t t e r of Thuja p l i c a t a (Minore, 1979), as well as that from the deciduous species Acer macrophyllum and Cornus n u t t a l l i i . The low LFH pH i n the Tsuga-Pseudotsuga-Polystichum forests (P5) i s probably linked to the abundance of Tsuga heterophylla and the a c i d i f y i n g e f f e c t s of i t s l i t t e r . From i t s c e n t r a l p o s i t i o n i n both the r e c i p r o c a l averaging o r d i -nation and the d i r e c t ordination of the Pseudotsuga group, the Pseudotsuga- Berberis forests (P4) appear to represent the c h a r a c t e r i s t i c mesic, (1) Cornus f l o r i d a , c l o s e l y r e l a t e d to C. n u t t a l l i i , has high concentra-tions of calcium i n i t s leaves (Thomas, 1969). 129 mid-slope community type of the inland part of the study area (Fig. 7a and b). The hypotheses put forward i n the Introduction concerning the close r e l a t i o n s h i p between vegetation and environmental patterns i n old-growth f o r e s t s , and the possible r o l e of major disturbances (hypotheses 2a and 2b), are we l l i l l u s t r a t e d i n the Pseudotsuga group. In general, vegetation patterns c l o s e l y match the environmental patterns, except f o r community types PI, P2 and P3 where the r e l a t i o n s h i p i s weak (Figs. 13 and 14). These three community types are found i n the warmest and d r i e s t areas where the Pseudotsuga group occurs, and where forest f i r e recurrence i s probably highest. The strong dominance of Pseudotsuga menziesii i n most stands, the abundance of charred bark on trees and charcoal i n the s o i l , a l l present d i r e c t evidence i n support of t h i s assumption. Thus, d i f f e r e n t f i r e h i s t o r i e s , rather than edaphic f a c t o r s , may be the cause of vege-t a t i o n a l differences between some of the community types within the Pseudotsuga group. 130 3. THE THUJA GROUP While macro-climate i s r e l a t i v e l y uniform within the coastal sector where most of the p l o t s from the Thuja vegetation group are found, the same cannot be said of s o i l parent material. S u r f i c i a l deposits vary from poorly drained marine clays or sands, to imperfectly drained cemented t i l l s and to w e l l drained colluvium. Considering the v a r i e t y of parent materials, a s o i l n utrient gradient very l i k e l y influences the vegetation pattern within the Thuja group. This i s supported by the numerous corre-l a t i o n s between the f i r s t r e c i p r o c a l averaging ordination axis of the Thuj a group and s o i l n utrient v a r i a b l e s , such as percent nitrogen i n LFH and B i horizons, and C/N. r a t i o i n the LFH (Table 10). This s o i l n utrient gradient appears to be linked to a s i t e p r o d u c t i v i t y gradient which, i n the d i r e c t i o n of increasing p r o d u c t i v i t y , i s r e f l e c t e d i n the vegetation by increasing maximum tree height, decreasing tree species richness and decreasing t o t a l coverage of the shrub and bryophyte s t r a t a (Table 10). Species richness i s expected to decrease towards more productive environ-ments, through increased competitive i n t e r a c t i o n between species (Del Moral, 1983). The increased amount of l i g h t r e s u l t i n g from the sparse overstory of poor s i t e s , seems e s p e c i a l l y favourable to the development of a very dense shrub l a y e r , where Gaultheria shallon and Vaccinium ovaturn are p a r t i c u l a r l y important. Two community types of the Thuja group, the coastal dry Thuja forests (Tl) and the coastal wet Thuja forests (T5), although at opposite ends of the moisture gradient (Fig. 8b) are grouped together at the nutrient-poor end of the s o i l n utrient gradient r e f l e c t e d on the f i r s t axis of the vegetation ordination (Fig. 8a). Coastal Tsuga-Blechnum-Polystichum forests (T2) have the best s o i l n utrient and 131 drainage c h a r a c t e r i s t i c s , and are probably the most productive forest communities within the Thuja group. Half of the p l o t s of t h i s community type occurred on ancient l a n d s l i d e s , which may have improved s o i l drainage and nutrient conditions. Coastal Tsuga-Blechnum-Polystichum forests are also found at mid-elevations on mountain slopes ( F i g . 8b), several kilometers away from the coast. Summer fogs r a r e l y occur at these mid-elevations, and t h i s may permit greater p r o d u c t i v i t y through increased solar r a d i a t i o n . The e f f e c t s of summer sea fogs on solar r a d i a t i o n and moisture have been described for the coast of C a l i f o r n i a (Azevedo and Morgan, 1974). An a l t i t u d i n a l gradient was also detected i n the Thuja vegetation group. The low elevation, widespread coastal Thuja forests (T4) i n t e r -grade at higher elevations with the c o a s t a l montane Thuja forests (T3), characterized by an increased importance of Abies amabilis i n the tree, sapling and seedling layers (Table 24). Along a s o i l moisture gradient, the d r i e s t s i t e s are rock outcrops where only the coastal dry Pinus f o r e s t s (D2) are found (Fig. 8b). Although a d i r e c t ordination separated the various community types or the Thuja group on a l t i t u d i n a l and topography-moisture gradients (Fig. 8b), these same gradients are not d i s t i n c t l y r e f l e c t e d i n the i n d i r e c t o r d i -nation based on vegetation data alone (Fig. 8a). Moreover, elevation does not seem to exert the strongest influence on vegetation, as was hypothesized i n the Introduction (hypothesis l c ) . Instead a s o i l nutrient gradient appears to be most c l o s e l y linked with the main vegetation v a r i a t i o n (Table 10). S o i l moisture appears to have l i t t l e influence 132 on vegetation patterns, probably because p r e c i p i t a t i o n exceeds 3 000 mm annually and s o i l water d e f i c i t s are non-existent (Fig. 2). Elevation i s c l e a r l y the second most important environmental gradient i n the canonical analysis of the Thuja group (Fig. 13, Table 21), but an o u t l i e r p l o t (no. 85) tends to obscure the r e l a t i o n s h i p with elevation i n the i n d i r e c t ordination (Fig. 8a, Table 10). Also strongly correlated with the second canonical axis i s percent slope (Fig. 13, Table 21), suggesting a l i n k between vegetation patterns and a gradient i n s o i l moisture, from saturated s o i l s at low elevations to better drained s o i l s at higher elevations. This could occur through better drainage (increased slope) and absence of fog at higher elevations. It should be noted also that previous studies demonstrating the strong c o r r e l a t i o n of elevation (hypothesis l c ) and moisture (hypothesis Id) gradients with the vegetation patterns of mountainous areas were ca r r i e d out i n d r i e r climates, where summer s o i l moisture d e f i c i t s occur frequently (Whittaker, 1956; 1960; Whittaker and Niering, 1965; Peet, 1981). Thus slope aspect and topographical p o s i t i o n are expected to influence vegetation patterns wherever s o i l moisture i s l i m i t e d . In the coastal part of t h i s study area, where s o i l moisture i s probably abundant year round on a l l slope aspects and most topographical p o s i t i o n s , the influence of s o i l moisture on vegetation patterns may be greatly reduced or n u l l i f i e d . Large scale disturbance by f i r e i s absent from areas near the coast, large scale windthrow i s infrequent and natural landslides r a r e l y occur. Thus, i t would appear than i n t h i s r e l a t i v e l y stable environment, old-growth 133 forests have become c l o s e l y attuned to t h e i r environments and vegetation accurately r e f l e c t s environmental gradients (hypothesis 2a), based on the r e s u l t s obtained from canonical analyses (Figs. 13 and 14, Tables 18 and 20). 134 4. THE ABIES GROUP The Abies vegetation group i s not associated with a s p e c i f i c geographical area; therefore, macro-climate (mostly p r e c i p i t a t i o n ) i s le s s homogeneous than i n the Pseudotsuga and Thuja groups. The Abies group i s characterized by the dominance of Abies amabilis or Tsuga  heterophylla, or both (Table 26). Environmentally, the majority of community types recognized within the group are found i n s i t e s with cool micro-climates. The lowland Abies forests (A5) are generally found at the bottom of steep v a l l e y s , often on north-facing slopes or on the upper terraces near r i v e r s . In the d r i e r parts of the study area, lowland Abies forests (A5) were,encountered most frequently i n r i v e r v a l l e y s at the base of steep north-facing slopes, while Tsuga-Pseudotsuga- Polys tichum forests (P5) occupied the opposite south-facing slopes (plots 29 and 27, Figs. 1, 7b and 9b). Such a d i s t r i b u t i o n may be explained by a cooler micro-climate on the northern aspect, where a le s s e r amount of solar r a d i a t i o n leads to lower evapotranspiration rates, higher s o i l moisture l e v e l s , and delayed snow melt i n the spring. Cold a i r drainage also may be involved i n the case of some narrow v a l l e y s . In northern Washington, Abies amabilis forests predominate between 600 to 1300 m i n elevation, where temperatures are cool, p r e c i p i t a t i o n i s high and snowpack i s deep (Teskey e_t a l . , 1984). Low summer water d e f i c i t s and low a i r temperatures have been reported as c h a r a c t e r i s t i c of areas where Abies amabilis i s dominant (Waring et a l . , 1972). The montane Abies-Streptopus f o r e s t s (A4) are a l l found above 600 m i n eleva-t i o n on north-facing slopes, inland within the study area (Fig. 9b). 135 This community type probably has the coldest environmental conditions of a l l those studied, except for the subalpine vegetation group. At lower elevations, but near the summit of small mountains near the coast, are found the montane Tsuga-Abies f o r e s t s (A3). This community type usually occurs immediately above stands of the coastal montane Thuja forests (T3), on steeper slopes with f a s t e r drainage, and higher proba-b i l i t i e s of wind disturbance. Plot 151 was sampled i n a dense stand of Tsuga heterophylla and Abies amabilis o r i g i n a t i n g from a complete wind-throw of the previous forest ( F ig. 9a and b). The montane Abies-Tsuga forests (A2) occur i n s i m i l a r topographical s i t u a t i o n s as the montane Tsuga-Abies f o r e s t s (A3), but at higher average elevation inland, where snowpack i s probably deeper and of longer duration. The higher r e l a t i v e d e n s i t i e s of Abies amabilis seedlings and saplings i n type A2, as compared to type A3, i n d i r e c t l y support t h i s suggestion. The Tsuga-Blechnum-Polystichum forests (A7) are one of the two community types within the Abies group to be almost e n t i r e l y dominated by Tsuga heterophylla. This i s s t r i c t l y a low elevation community type, where r e l a t i v e l y recent disturbances (100-200 years) may have played an important r o l e i n the strong Tsuga heterophylla dominance. However, the Tsuga-Gaultheria-Blechnum forests (A6), also dominated by Tsuga heterophylla, appear to be c l i m a t i c a l l y c o n t r o l l e d and probably represent an intermediate community type along a p r e c i p i t a t i o n gradient beginning with the coastal Thuja forests (T4) and ending i n the d r i e s t inland sector around Port A l b e r n i , with community types of the Pseudotsuga group. F i n a l l y , the montane Tsuga-Abies-Gaultheria forests (Al) occupy the d r i e s t habitats within the Abies vegetation group (Fig. 9b). 136 In terms of the major environmental gradients correlated with vegetation patterns i n the Abies group, hypotheses formulated e a r l i e r appear to be confirmed ( l c and Id), although the precondition that macro-climate be uniform i s not held. I t i s possible that strong micro-climatic e f f e c t s override macro-climate i n the case of the Abies group. The Abies community types found i n the i n t e r i o r of the study area, may avoid s o i l moisture d e f i c i t s and high temperatures because they occupy habitats with c h a r a c t e r i s t i c a l l y cool and moist micro-climates (types A2, A4 and A5). A c l i m a t i c gradient, from the cool climates where community types A4, A5 and A2 are found to the milder climates where the A7, A6 and A3 community types are found, i s r e f l e c t e d i n the f i r s t axis of the r e c i -p rocal averaging ordination (Fig. 9a). The t h i r d axis separates the only community type of dry habitats (Al) from the other types. The d i r e c t ordination of the plo t s also i l l u s t r a t e s these gradients of meso-climate (linked to elevation) and s o i l moisture (linked to slope aspect and topographical p o s i t i o n ) . a f i n e r topographical p o s i t i o n scale would probably resolve the overlap between types A7 and A5 (Fig. 9b). The i n t e r p r e t a t i o n of the canonical analysis of the Abies group i s l i m i t e d because only four environmental variables were used. Never-theless, low elevation community types (A5, A6, A7) are separated from higher elevation community types (A4, A2, A3), and those occurring on steep slopes (A2, A3) are separated from those occurring on gentle slopes or l e v e l t e r r a i n (A5, A6) (Fig. 13, Table 21). Increasing organic horizons thickness, p o s i t i v e l y correlated with the f i r s t canonical axis (Table 21), i s c h a r a c t e r i s t i c of the montane Abies-Streptopus forests (A4), where cooler temperatures and long snowpack duration are expected 137 to impede organic matter decomposition. It i s s u r p r i s i n g to note how s i m i l a r vegetationably the montane Abies-Streptopus forests (A4) are to the lowland Abies forests (A5), but how d i s s i m i l a r they are environmentally (Figs. 9a and 14, Tables 19, 20, 26 and 27). Environmental s i m i l a r i t y would undoubtedly increase i f c l i m a t i c v a r i a b l e s were a v a i l a b l e to include i n the analyses, allowing micro-climatic s i m i l a r i t i e s between the two types to surface. 138 5. VEGETATION CLASSIFICATION C l a s s i f i c a t i o n of i n d i v i d u a l p l o t s into broad vegetation groups, as w e l l as into more narrowly defined community types was acheived using successive ordinations of the vegetation data (Peet, 1980). O v e r a l l , the community types and vegetation groups defined following t h i s approach also d i f f e r environmentally. This i s demonstrated by the canonical analysis of a l l community types and the subalpine vegetation group based s o l e l y on environmental data (Fig. 14). These r e s u l t s generally ind i c a t e that differences at the plant community l e v e l are p a r a l l e l e d by d i f f e -rences at the environmental l e v e l within the study area (hypothesis 2a). Such a close vegetation - environment correspondance was expected at the outset of t h i s study because of the sampling of "old-growth" f o r e s t s . The e f f e c t s of f i r e disturbance are probably at le a s t p a r t i a l l y responsible f o r the weaker matching between vegetational and environmental differences encountered i n some community types within the Pseudotsuga group;(types PI, P2 and P3). D i f f e r i n g f i r e disturbance h i s t o r i e s are hypothesized to be the cause of the differ e n c e i n vegetation composition between these p a r t i c u l a r community types. S o i l seepage, unaccounted for i n the set of measured environmental v a r i a b l e s , also may explain why the Pseudotsuga-Thuj a-Acer forests (P2), with a c h a r a c t e r i s t i c a l l y mesic vegetation, are grouped environmentally with the Pseudbtsiiga-Linnaea forests (P3) of d r i e r habitats i n F i g . 14. However, these r e s u l t s (Fig. 14) represent only the f i r s t two canonical axes. When Mahalanobis squared distances accounting for a l l dimensions are inspected, we f i n d that the dry Pseudotsuga forests (PI) are much more environmentally 139 s i m i l a r to the Pseudotsuga-Linnaea forests (P3), than t h i s l a t t e r commu-n i t y type i s to the Pseudotsuga-Thuj a-Acer forests (P2) (Table 20). Therefore, community types PI and P3 are the most l i k e l y to have vegeta-t i o n a l differences based on d i f f e r i n g f i r e h i s t o r i e s because they are the most environmentally s i m i l a r . The Pseudotsuga-Thuja-Acer f o r e s t s (P2) are thus more l i k e l y to show vegetational differences from types PI and P3 on the basis of the presence of unrecorded s o i l seepage. Evidence from discriminant analyses also suggests a weaker r e l a t i o n -ship between environmental c h a r a c t e r i s t i c s and vegetation composition i n the Pseudotsuga group. Using discriminant functions based on envi-ronmental data to r e - c l a s s i f y p l o t s into community types ( o r i g i n a l l y defined by composition) i t was found that a correct r e - c l a s s i f i c a t i o n was obtained for 62.5 % of the p l o t s from the Pseudotsuga group. In the Thuja vegetation group the r e - c l a s s i f i c a t i o n success was 69.4 %. Re-c l a s s i f i c a t i o n success for a l l community types analyzed together was 72.5 % (Appendix 4). This shows a lower concordance between environ-mental c h a r a c t e r i s t i c s and vegetation composition i n the Pseudotsuga group, subjected to large scale f i r e disturbances, as compared to the Thuja group where disturbances are l e s s prevalent, or to the en t i r e study area. Thus, the hypothesis formulated e a r l i e r regarding the e f f e c t of disturbance seems to hold (Introduction, 2b). High environmental s i m i l a r i t i e s between community types of d i f f e r e n t vegetation groups i s observable between the T2 type of the Thuja group and the A7 type of the Abies group, as well as between the A l type of the Abies group and the P6 and P7 types of the Pseudotsuga group (Fig. 14, 140 Table 20). In both cases these community types are environmentally more s i m i l a r to types of another vegetation group, than to community types within t h e i r own vegetation group. This resulted from the separation of p l o t s for further analyses through successive ordinations; these p a r t i c u l a r community types being near the edges of separated p l o t c l u s t e r s on the ordination diagrams. This s i t u a t i o n can be seen as a r e f l e c t i o n of the continuous nature of vegetation, and an excellent example of the d i f f i c u l t y encountered i n attempts at p a r t i t i o n n i n g t h i s continuum for c l a s s i f i c a t i o n purposes. The vegetational and environ-mental differences between these community types are s u f f i c i e n t to maintain t h e i r separate status. However, the coastal Tsuga-Blechnum-Polystichum forests (T2) might f i t j u s t as well with the Abies vegetation group; s i m i l a r l y , the montane Tsuga-Abies-Gaultheria forests (Al) could be included with the Pseudotsuga group (Fig. 14, Table 20). Environmental differences detected through the canonical analyses are sometimes s l i g h t between two community types which are d i f f e r e n t i a t e d v e g e t a t i o n a l l y along only one major environmental gradient, such as e l e -vation. This i s p a r t i c u l a r l y evident i n the case of the Pseudotsuga- Berberis forests (P4) and the montane Tsuga forests (P6), adjacent community types along an elevation gradient of mesic s i t e s on inland mountain slopes (Figs. 7a, 7b and 14, Table 20). Environmental r e l a t i o n s h i p s between community types of the three larger vegetation groups were analyzed i n d i v i d u a l l y within each group (Fig. 13). The r e s u l t s are s i m i l a r to those obtained i n a global analysis of a l l community types from a l l vegetation groups (Fig. 14). The l a t t e r 141 analysis has the advantage of showing the r e l a t i o n s h i p s between community types of d i f f e r e n t vegetation groups, as w e l l as possibly improving the c h a r a c t e r i z a t i o n of within group r e l a t i o n s h i p s through increased t o t a l v a r i a t i o n i n the environmental v a r i a b l e s employed. 142 6. THE CLIMATIC MASTER GRADIENT The successive vegetation ordination approach has revealed a v a r i e t y of environmental gradients correlated with vegetation v a r i a t i o n i n each set of p l o t s analysed. A macro-climatic gradient from low eleva t i o n vegetation to subalpine forests was detected i n the f i r s t ordination, as well as a parent material gradient from floodplains to rock outcrops (Fig. 5). A subsequent ordination detected what appeared to be a general gradient of increasing distance from the coast, linked with macro-climate (Fig. 6). In other ordination of smaller groups of pl o t s , gradients of elevation (meso-climate), s o i l moisture (topography) and s o i l n u t r i e n t factors were correlated with vegetation patterns. The major macro-climatic gradient of p r e c i p i t a t i o n occurring i n the study area had not been c l e a r l y i d e n t i f i e d i n the vegetation ordinations, except perhaps i n the one using 140 p l o t s (Fig. 6). Thus, an ordination of modal p l o t s was done i n order to assess the importance of t h i s macro-cl i m a t i c gradient on the general vegetation patterns within the e n t i r e study area. The modal p l o t s were selected from a l l the sampled p l o t s with the objective of producing a data set i n which edaphic and meso-cl i m a t i c v a r i a t i o n s would be minimized. Such a technique has been c a l l e d the "functional approach to plant community ecology" (Austin et_ al_. , 1984) and assumes that i f c e r t a i n factors known to influence vegetation are held constant, i n t h i s case through data manipulation, the r e l a t i o n s h i p between vegetation and the factor allowed to vary can be analyzed. Plots located at both extremities of the edaphic gradients of s o i l moisture and s o i l nutrients were eliminated, as well as p l o t s at the cooler end of meso-climatic or micro-climatic gradients. Modal plo t s represent low-143 to mid-elevation s i t e s of intermediate edaphic conditions throughout the study area. Because of the s e l e c t i o n c r i t e r i a , very few p l o t s were i n -cluded from the Abies vegetation group. The majority of modal p l o t s come from the Pseudotsuga and Thuja vegetation groups, both occurring i n geographically d i s t i n c t areas. The r e s u l t s of the r e c i p r o c a l averaging ordination of the modal pl o t s show that the vegetation pattern expressed on the f i r s t two axes i s strongly correlated with the distance from the coast (Fig. 10, Table 14). It i s assumed that the distance from the coast gradient i s c l o s e l y linked to a steep p r e c i p i t a t i o n gradient. Evidence for t h i s major c l i m a t i c gradient i s e a s i l y obtained (Figs. 2 and 12). P r e c i p i t a t i o n decreases from an average of over 3 000 mm annually to le s s than 2 000 mm within a 60 km distance from the coast (Fig. 2). The same trend can be seen during the growing season ( f i g . 12), when s o i l water d e f i c i t s are most l i k e l y to occur inland (Fig. 2). The steepness of t h i s p r e c i p i t a -t i o n gradient i s a r e s u l t of orographic p r e c i p i t a t i o n and r a i n shadow e f f e c t s caused by the i n t e r c e p t i o n of moisture laden a i r masses by high mountains p a r a l l e l to the coast. Even though the annual mean temperature i s only s l i g h t l y higher inland than on the coast (Fig. 2), t h i s d i f f e r e n c e translates into 200—300 extra e f f e c t i v e growing degree-days annually for the inland areas (Fig. 12). Therefore, more heat i s a v a i l a b l e inland for the growth of plants. However, s o i l moisture d e f i c i t s may be encountered inland during July or August (Fig. 2). The p r e c i p i t a t i o n gradient d i r e c t l y influences a disturbance type gradient. F i r e disturbance i s undoubtedly predominant i n i t s scale: and i t s e f f e c t on vegetation at the low p r e c i p i t a t i o n end of the gradient 144 (Table 14). Towards the coast, with increasing p r e c i p i t a t i o n and the absence of s o i l moisture d e f i c i t s , f o rest f i r e s r a r e l y occur and the main disturbances are caused by wind (Klinka et_ a l . , 1979). Improving drainage away from the coast r e f l e c t s a natural change i n topography to steeper slopes and more abundant c o l l u v i a l material, as well as a much shorter annual period of s o i l saturation (Table 14). Numerous other s o i l a t t r i b u t e s vary along the distance from the c o a s t - p r e c i p i t a t i o n gradient (Table 14). The strongest c o r r e l a t i o n i s with the organic horizons t h i c k n e s s / e f f e c t i v e rooting depth r a t i o . This r a t i o decreases inland, where trees are more deeply rooted into the mineral s o i l , and increases towards a value of 1 near the coast, where the e f f e c t i v e rooting depth often coincides with the thickness of the organic horizons (Table 14, F i g . 12). The thickness of the organic horizons i s , i n turn, probably related to climate. P l e n t i f u l moisture and mild temperatures lead to abundant and nearly continuous plant growth on the coast, and to the accumulation of thick organic s o i l horizons (Valentine, 1971). Decomposition may be slowed by a heat d e f i c i t , compared to inland areas. Plant p r o d u c t i v i t y i s probably reduced inland by summer s o i l moisture d e f i c i t s and by colder winter temperatures, leading to a lesser accumula-t i o n of l i t t e r . Decomposition of t h i s l i t t e r probably proceeds f a s t e r than on the coast because of higher summer temperatures. Organic horizons thickness i s also p a r t i a l l y related to the type of vegetation and the type of l i t t e r produced, i n f l u e n c i n g decomposition rates and by-products ( a c i d i t y , n u t r i e n t s ) . However, vegetation i t s e l f i s also c l o s e l y related to the p r e c i p i t a t i o n gradient. Whether the climate or the vegetation exerts the strongest influence on organic horizons thickness may be d i f f i c u l t to assess. 145 D i f f e r e n t tree species are known to have d i s t i n c t rooting depth patterns (Minore, 1979; E i s , 1974; McMinn, 1963; Strong and La Roi, 1983). Pseudotsuga menziesii, dominant inland, i s known to be a deep rooting species (Minore, 1979). Thuja p l i c a t a , Tsuga heterophylla and Abies  amabilis, dominants near the coast, are known to be shallow rooting (Minore, 1979). Shallow e f f e c t i v e rooting near the coast also may r e s u l t p a r t i a l l y from increased waterlogging of the s o i l as a product of high p r e c i p i t a t i o n . Whatever the cause, i t remains that the tree root mass i s often r e s t r i c t e d to the organic horizons i n natural f o r e s t communities near the coast. As distance from the coast increases, the tree root mass occupies more and more of the mineral s o i l . This tendency i s correlated with increasing dominance by Pseudotsuga menziesii and decreasing p r e c i p i t a t i o n (Figs. 11 and 12). Total tree basal area tends to increase towards the coast and may indic a t e an increase i n fo r e s t p r o d u c t i v i t y linked with the p r e c i p i t a t i o n gradient (Table 14). Maximum tree height decreases near the coast, possibly r e f l e c t i n g the change i n dominant tree species (Waring and Fra n k l i n , 1979) or increasing wind disturbance, or both (Table 14). The vegetation pattern and changing environmental v a r i a b l e s along the p r e c i p i t a t i o n gradient are documented by the ordination of modal plo t s (Fig. 10) and by c o r r e l a t i o n s between s i t e v a r i a b l e s and ordination axes (Table 14). Also of i n t e r e s t i s the graph showing the d i s t r i b u t i o n patterns of major tree species along t h i s same gradient (Fig. 11). Pseudotsuga menziesii and Thuja p l i c a t a each a t t a i n t h e i r maximum and minimum basal areas, at opposite ends of the gradient (Fig. 11). Although not indicated i n the graph, Thuja p l i c a t a i s present i n small amounts at 146 the dry end of the gradient, but the polynomial curve follows the best f i t of the more abundant data near the wetter end of the gradient. The presence of a Pseudotsuga menziesii peak at the dry end of the gradient i s not su r p r i s i n g i n l i g h t of t h i s species' well known adaptation to f i r e (Franklin and Dyrness, 1973; Minore, 1979). Other species, such as Tsuga heterophylla, Thuja p l i c a t a and Abies amabilis, possess th i n bark and are usually k i l l e d by f i r e . These species are also more tolerant of cooler temperatures (or less heat a v a i l a b l e for growth) as can be i n f e r r e d from t h e i r northern d i s t r i b u t i o n s along the coast, whereas Pseudotsuga  menziesii reaches i t s northern c o a s t a l d i s t r i b u t i o n l i m i t on Vancouver Island (Krajina e t a l . , 1982). The s l i g h t decrease i n Pseudotsuga menziesii and increase i n Tsuga heterophylla basal areas past the 50 km mark may be a response to increasing orographic p r e c i p i t a t i o n caused by a second major ridge of mountains j u s t west of Port A l b e r n i (Fig. 11). Towards the wet end of the gradient Thuja p l i c a t a reaches an average basal area of 120 m 2/hectare i n modal vegetation 10-15 km from the coast, then declines to les s than 80 m2/ha within 5 km of the coast. This decline could r e f l e c t a lowered forest p r o d u c t i v i t y near the coast due to the high frequency of summer fogs. These fogs reduce the amount of solar r a d i a t i o n reaching the fo r e s t canopy, thus reducing photo-synthesis and impeding evapotranspiration rates. Although low produc-t i v i t y sometimes r e s u l t s from low s o i l n utrient l e v e l s , t h i s seems u n l i k e l y here since percent s o i l nitrogen increases towards the coast, i n both the organic LFH and mineral Bj horizons (Table 14). Abies amabilis basal area increases l i n e a r l y i n modal vegetation towards the coast (Fig. 11), i n agreement with the general autecological c h a r a c t e r i s t i c s ascribed to t h i s species (Minore, 1979; Krajina et al.., 1982). 147 The r e l a t i o n s h i p between basal area and. distance from the coast i s more complex i n Tsuga heterophylla than i n the other species examined (the polynomial equation for T_. heterophylla has the lowest r 2 value, F i g . 11). Toward the dry end of the gradient, the observed drop i n basal area mayv r e f l e c t >a combination of f i r e disturbance and sub-optimal moisture conditions. Toward the coast, the decline and s l i g h t r i s e i n Tsuga heterophylla basal area coincide with an opposite trend i n Thuja  p l i c a t a . This i s suggestive of a comptetitive i n t e r a c t i o n between the two species (possibly for space which i s occupied for greater periods by the longer l i v e d Thuja p l i c a t a (Waring and Fr a n k l i n , 1979)) since a b i o t i c conditions near the coast are u n l i k e l y to impair the growth of Tsuga heterophylla. In only a small segment of the gradient does Tsuga  heterophylla become the dominant tree i n terms of basal area (29 to 31 km from the coast). This region appears to represent a t r a n s i t i o n zone between coastal and inland f o r e s t types where, perhaps, decreased compe-t i t i o n from the other dominants permits better growth i n Tsuga heterophylla. The organic horizons t h i c k n e s s / e f f e c t i v e rooting depth r a t i o also varies with distance from the coast (Figs. 11 and 12). The r a t i o i s lowest toward the dry end of the gradient, i n the regionrof Pseudotsuga menziesii's peak i n basal area, and increases towards the wetter end of the gradient. This r a t i o r e f l e c t s the d i f f e r e n t u t i l i z a t i o n of the s o i l horizons (organic vs. mineral) by the roots of the changing assemblage of tree species along t h i s major c l i m a t i c gradient (Pseudotsuga menziesii vs. Thuja p l i c a t a ) . The r e s u l t s i l l u s t r a t e d by Figure 11 have major implications for forest management. Because of i t s economic d e s i r a b i l i t y , Pseudotsuga  menziesii has been f or many years the preferred species for replanting a f t e r 148 logging i n t h i s area. Yet the data presented here show that Pseudotsuga  menziesii i s not an important species within 25 km of the coast, and that i t i s t o t a l l y absent within 15 km of the coast on modal s i t e s ( F i g . 11). Pseudotsuga menziesii i s present near the coast, however, i n a few non-modal s i t e s such as rock outcrops (e.g. the coastal dry Pinus f o r e s t s , Table 24), although such s i t e s are unproductive and are not usually logged. Other more productive s i t e s , which may be considered modal, have been replanted with Pseudotsuga menziesii a f t e r logging. These s i t e s , often very near to the coast, previously would have'supported mature stands of Thuja p l i c a t a , Tsuga heterophylla and Abies amabilis. The absence of Pseudotsuga menziesii from the n a t u r a l modal vegetation could be a t t r i b u -ted simply to the lack of forest f i r e s , although other types of disturbances, such as blowdowns and l a n d s l i d e s , occasionally occur which would create openings for t h i s species. A few Pseudotsuga menziesii trees have indeed been found near the coast on steep slopes of old l a n d s l i d e colluvium i n the Cypre River v a l l e y and near Kennedy Lake. Nevertheless, the question remains why Pseudotsuga menziesii i s not a more widespread and important species i n the immediate v i c i n i t y of the coast. The answer to t h i s question may have been found recently by Spiers et a l . (1983) studying Pseudotsuga menziesii plantations near the coast. The trees i n these plantations are s t a r t i n g to show serious growth defects, 20 to 30 years a f t e r p l anting. Abnormally high l e v e l s of arsenic have been detected i n the leaders of planted Pseudotsuga menziesii, while l e v e l s i n adjacent, n a t u r a l l y regenerating species were near background l e v e l s (Spiers e_t a l . , 1983). These authors have suggested that arsenic i s found i n an arsenate form (Sadiq e_t a l . , 1983), analogous to a form of phosphate 149 absorbed by plants, i n the frequently waterlogged mineral s o i l . Anaerobic and reducing conditions encountered i n saturated s o i l s may hinder also the natural p h y s i o l o g i c a l processes of s e l e c t i v e s o i l nutrient uptake by Pseudotsuga menziesii roots, leading to the uptake of p o t e n t i a l l y toxic arsenate along with the nutrient phosphate. High arsenic concentrations i n the meristems of the tree could possibly cause growth defects by i n t e r f e r i n g with the synthesis of plant growth hormones (Spiers e_t al_., 1983). The delay i n the appearance of symptoms probably i s r e l a t e d to the time required by the deep , rooting Pseudotsuga menziesii to reach the satured lower horizons where arsenic w i l l occur i n the arsenate form . The delay also could be r e l a t e d to a slow accumulation of arsenic up to a c r i t i c a l point when t o x i c i t y occurs. S o i l saturation i s probably highest i n the spring when active growth i s taking place (Spiers et^ al_., 1983) . Waterlogging i s probably increased on the p l a n t a t i o n s i t e s following the removal of the o r i g i n a l vegetation which removes large amounts of s o i l moisture through evapotranspiration. These excessive s o i l moisture con-d i t i o n s at greater depths are avoided by Thuja p l i c a t a , Tsuga heterophylla and Abies amabilis because of t h e i r shallow rooting habits. Avoidance of saturated s o i l horizons probably occurs also for Pseudotsuga menziesii on the r a p i d l y drained s i t e s , such as rock outcrops and old l a n d s l i d e colluvium, where i t i s found near the coast. Carter e_t a l . (1984) have described growth abnormalities, i d e n t i c a l to those reported by Spiers et_ a l . (1983), i n other coastal plantations of Pseudotsuga menziesii. They t e n t a t i v e l y diagnosed a boron de f i c i e n c y from tissue and s o i l analyses, although arsenic concentrations were not reported. 150 An increase i n alpha d i v e r s i t y of vascular plants (species richness) with increasing c o n t i n e n t a l i t y , or distance from the coast, was observed by Whittaker (1960) i n the f o r e s t vegetation of south-coastal Oregon. Del Moral and Watson (1978) reported s i m i l a r findings for the Washington Cascades. Oksanen (1983) describes an increase i n alpha d i v e r s i t y of lichens and vascular plants with increasing c o n t i n e n t a l i t y i n Finland. These trends were observed also i n western Vancouver Island, supporting hypothesis l e formulated i n the Introduction. The alpha d i v e r s i t y gradient i s p a r t i c u l a r l y steep i n the case of vascular plants, with fewer than 16 species occurring on average i n the 0.05 ha p l o t s near the coast, increasing to an average of more than 26 species i n inland p l o t s (Fig. 12). Bryophyte species richness appears to increase towards the wetter coastal areas, while vascular species richness increases towards the more c o n t i -nental and d r i e r areas, p a r t i c u l a r l y the herb layer (Table 19). Numerous factors have been proposed to account for gradients i n vascular plant d i v e r s i t y , but a synthesis of the causes underlying the patterns at d i f f e r e n t scales has not yet been acheived. At the micro-scale l e v e l , Del Moral's (1983) experimental r e s u l t s , based on the t h e o r e t i c a l and conceptual frameworks of Grime (1980), Tilman (1980) and Huston (1979), demonstrate the e f f e c t s of a combined i n t e r a c t i o n of s i t e p r o d u c t i v i t y , disturbance l e v e l and moisture stress on species d i v e r s i t y i n subalpine meadows. On a larger regional scale, Whittaker (1975) suggested that s i t e p r o d u c t i v i t y and moisture l e v e l s were not the major controls of vascular plant alpha d i v e r s i t y , but that heat (possibly measured by growing degree-days) may represent the key f a c t o r . Recent experimental r e s u l t s i n d i c a t e that the most productive s i t e s have lower 151 alpha d i v e r s i t y than s i t e s with intermediate p r o d u c t i v i t y (Del Moral, 1983). The explanation offered i n t h i s case i s that competitive i n t e r a c t i o n s between species tend to reduce d i v e r s i t y i n productive s i t e s . Extreme ph y s i c a l stress also tends to reduce d i v e r s i t y , but i t enhances i t at intermediate l e v e l s by again preventing or reducing competitive i n t e r -actions (Del Moral, 1983). Disturbance plays a major r o l e i n increasing d i v e r s i t y , and the more productive the s i t e the more frequent the d i s -turbances must be i n order to prevent the competitive exclusion of several species by one or a few dominants (Del Moral, 1983). Thus, i t may be that the more frequent large scale forest f i r e disturbances of the i n t e r i o r part of the study area enhance vascular plant alpha d i v e r s i t y . On the other hand, the r e l a t i v e l y stable environment of the coastal sector may allow strong competitive i n t e r a c t i o n s to take place and reduce d i v e r s i t y . Dominance concentration (Whittaker, 1975; Peet, 1974) i s also much higher i n the shrub and herb s t r a t a of the community types of the Thuja group than of the Pseudotsuga group (Tables 23 and 25). High dominance concentration (= low e q u i t a b i l i t y ) implies that a stratum, or community, i s strongly dominated by one or a few species (Whittaker, 1975). Beta d i v e r s i t y also has been observed to increase from coastal to more continental areas (Whittaker, 1960; Del Moral and Watson, 1978). As used here, beta d i v e r s i t y r e f e r s to the number of half-changes i n 1 Beta d i v e r s i t y = (log a - log z)/log 2, where a = r e p l i c a t e p l o t s s i m i l a r i t y , and z = extreme p l o t s s i m i l a r i t y . P l o t s i m i l a r i t i e s were measured using the cosine function which r e f l e c t s quantitative changes i n species representation. 152 compositional s i m i l a r i t y that occur along d i s t i n c t environmental gradients (Whittaker and Woodwell, 1978). This measure was useful for comparing vegetation-environment r e l a t i o n s h i p s i n two geographically d i s t i n c t groups of p l o t s along the major r a i n f a l l gradient : (1) the Pseudotsuga vegetation group representing the d r i e r , more continental i n t e r i o r sector, and (2) the Thuja group representing the very humid, coastal sector. Beta d i v e r s i t y along a s o i l moisture gradient (at low elevation) was 4.8 i n the Pseudo- tsuga group (endpoints : p l o t s 110 and 17, F i g . 7b); i n the Thuj a group (endpoints : p l o t s 53 and 50, F i g . 8b) beta d i v e r s i t y was 0.7. Along an elevation gradient, values of 4.7 i n the Pseudotsuga group (endpoints : p l o t s 13 and 139, F i g . 7b) and 0.3 i n the Thuja group (endpoints : 50 and 152, F i g . 8b) were obtained. Difference i n t o t a l lengths of the elevation gradients concerned (800 m i n the Pseudotsuga group and 600 m i n the Thuja group) are considered i n s u f f i c i e n t to explain the large discrepancy i n the beta d i v e r s i t y values c a l c u l a t e d . The decline i n temperatures with increasing elevation probably leads to greater moisture a v a i l a b i l i t y through reduced evapotranspiration, thus superimposing a s o i l moisture gradient on elevation. This could explain the high beta d i v e r s i t y of the Pseudotsuga group along the elevation gradient, since s o i l moisture conditions would be expected to vary more widely with e l e v a t i o n here than i n the Thuj a group. Evapotranspiration would not be expected to d i f f e r s i g n i f i c a n t l y between high and low elevations i n the Thuja group, because of the frequent occurrence of summer fogs at low e l e v a t i o n . The higher beta d i v e r s i t y of the Pseudotsuga group along the s o i l moisture gradient at low elevation probably r e f l e c t s - the greater length of t h i s gradient i n the d r i e r i n t e r i o r sector. Differences between dry 153 and wet habitats are greater i n absolute terms i n dry areas (vegetation growing on rock outcrops experiences longer periods of drought i n dry areas than i n areas of high p r e c i p i t a t i o n ) . On the other hand, wet habitats would be s i m i l a r i n terms of absolute s o i l moisture a v a i l a b i l i t y , i n wet or dry areas. Slope aspect e f f e c t s on s o i l moisture and on the amount of heat a v a i l a b l e for growth are also l i k e l y to be stronger i n the d r i e r , i n t e r i o r sector. Thus, the trends i n beta d i v e r s i t y i d e n t i f i e d here are i n general agreement with r e s u l t s from other studies on coastal forests (whittaker, 1960; Del Moral and Watson, 1978). The same trend applies along both the environmental gradients of s o i l moisture and elevation. 154 7. HOMOGENEITY AND SPECIES RICHNESS OF STRATA The i n v e s t i g a t i o n of homogeneity i n separate s t r a t a of fourteen community types supports the t h i r d hypothesis formulated i n the Introduction (Table 31). The community types of the Pseudotsuga vegetation group have, on average, a vegetation homogeneity of 0.72, while community types of the Thuja vegetation group have, on average, a vegetation homogeneity of 0.84. The high mean f i r e indices within the Pseudotsuga group ind i c a t e that f i r e i s a common form of disturbance (Table 31); the opposite i s true for the community types of the Thuja group (Table 31). Thus, i t appears that large scale disturbances such as f i r e may tend to reduce vegetation homogeneity. If the vegetation of the two groups i s compared on a stratum by stratum basis, few differences are seen for the tree, seedling and bryophyte-lichen layers (Table 31). The largest d i f f e r e n c e occurs at the l e v e l of the herb stratum, with an average homogeneity of 0.96 i n the Thuja group and 0.47 i n the Pseudotsuga group. The shrub and sapling layers are also markedly more homogeneous i n the Thuja vegetation group. I n t e r e s t i n g l y , a s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n e x i s t s , over a l l types, between increasing f i r e index values and decreasing homogeneity of the herb and shrub s t r a t a (r = -.589 and -.425). The reverse occurs i n the tree stratum, where homogeneity increases with increasing f i r e index values (r = .358). This r e s u l t r e f l e c t s the abundance of homogeneous p o s t - f i r e stands strongly dominated by Pseudotsuga menziesii, the only major tree species of the study area w e l l adapted to f o r e s t f i r e d i s -turbances . 155 The seedling stratum i s generally the most homogeneous within the e n t i r e study area (Table 31). The explanation for t h i s may be that most communities have closed canopies permitting only shade tolerant tree seedlings to germinate and become established. In support of t h i s hypo-th e s i s , i t can be seen that rock outcrop communities, with open canopies and mixtures of shade tolerant and i n t o l e r a n t seedlings, have lower seedling layer homogeneities. Floodplain forests ( F l ) , often r e l a t i v e l y open and with i d e a l germination and early growth conditions (ample moisture and s o i l n u t r i e n t s ) , have the lowest seedling stratum homogeneity of the community types studied (Table 31). The l e a s t homogeneous vege-t a t i o n layer i s by far the bryophyte-lichen layer. This stratum i s strongly influenced by the micro-heterogeneity of the forest f l o o r . An exception i s found i n the very homogeneous bryophyte-lichen layer of the Pseudotsuga- Linnaea forests (P3). This community type i s characterized by a nearly complete cover of Hylocomium splendens giving i t the highest dominance concentration (= lowest */X value or highest X value) for t h i s layer i n a l l the community types described (Tables 23, 25 and 27). In f a c t , as a general r u l e i t appears that any vegetation stratum with a high homogeneity i s l i k e l y to have a strong dominance concentration, which means that one species has a much higher coverage, or r e l a t i v e density, than other species i n the layer. The extremely homogeneous shrub and herb layers of the coastal Thuja f o r e s t s (T4) are a good example (Tables 25 and 31), as are the sapling and seedling layers of the Tsuga-Blechnum-Polystichum forests (A7) (Tables 26 and 31). The two most homogeneous community types are the coastal wet Thuja forests (T5) and the coastal Thuja forests (T4) :(Table 31). The coastal 156 wet Thuja forests(T5) have extremely homogeneous vegetation s t r a t a , a l l above 0.9 except for the bryophyte l a y e r . This community type i s found only within a narrow range of environmental conditions, disturbances are rare, and i t i s not very widespread (Fig. 8b). The c o a s t a l Thuja f o r e s t s (T4), on the other hand, occupy a wider range of environments near the coast (Fig. 8b). This, and the f a c t that the 19 p l o t s used to c a l c u l a t e the homogeneity values came from a r e l a t i v e l y large area, amplifies the extraordinary homogeneity of these f o r e s t s . The herb stratum i s remarkable with i t s homogeneity of 0.98. This undoubtedly r e s u l t s from the nearly exclusive dominance of Blechnum spicant, growing profusely on the thick, forest f l o o r organic horizons c h a r a c t e r i s t i c of t h i s community type (Table 25). The reasons for such high homogeneity may l i e i n the r e l a t i v e l y uniform climate, with no extreme temperatures, abundant moisture and a very low frequency of major disturbances. F i r e i s v i r t u a l l y absent, and major windthrow i s unusual at the low elevations where these forests occur. Occasionaly, i n d i v i d u a l trees are blown down, but such occurrences do not appear to i n i t i a t e s i g n i f i c a n t changes i n understory conditions because of the n a t u r a l l y open nature of the canopy of very large and widely spaced Thuja p l i c a t a trees. This combination of minimal disturbance and optimal plant growth conditions seems, i n large part, responsible for the low species richness and d i v e r s i t y , and the concentration of dominance i n a small number of species i n each stratum. In the coastal Thuja forests (T4) the increasing homogeneity through seedling, sapling, and tree layers, suggests that a process of elimination (through competition?) takes place during the development of the forest canopy (Table 31). This may be related to the longevity of Thuj a p l i c a t a , whose l i f e span i s twice that of 157 co-dominant tree species (Waring and F r a n k l i n , 1979). This inference of a monopolization of space by a long-lived species corresponds to the i n h i b i t i o n model of Connell and Slatyer (1977). The l e a s t homogeneous community type are the f l o o d p l a i n f orests (Fl) (Table 31). Colonization of floodplains a f t e r disturbance i s more l i k e l y linked to stochastic events and a v a i l a b l e seed sources than to the e c o l o g i c a l tolerances of species. The d i f f e r i n g ages of formation of the floodplains sampled, as w e l l as t h e i r d i f f e r i n g flooding regimes, add to the observed heterogeneity. Compared with other community types, the s u r f i c i a l materials of floodplains are much younger and are subject to a higher disturbance frequency i n the form of floodings (mechanical damage or new sediment deposition). The high species richness of the herb stratum of the f l o o d p l a i n f orests (Fl) appears l a r g e l y linked to t h i s more or le s s regular and frequent disturbance regime as w e l l , because a low species richness would be predicted for such productive s i t e s (Table 31). Del Moral (1983) has shown that with increasing s i t e p r o d u c t i v i t y , d i s -turbance regime had to increase as w e l l to maintain species d i v e r s i t y by reducing the occurrence of competitive i n t e r a c t i o n s . Floodplain f o r e s t s (Fl) have the highest species richness of community types of mesic habitats within the study area (Table 30). No d i s t i n c t r e l a t i o n s h i p was found between species richness and homogeneity of vegetation s t r a t a when a l l community types and a l l s t r a t a were considered, possibly because the data were too heterogeneous for any c l e a r trends to emerge. 158 B. COMMUNITY DYNAMICS Since the p u b l i c a t i o n of a seminal paper by Henry and Swan (1974) there has been a growing recognition of the importance of natural disturbances i n the composition, structure and dynamics of nearly a l l n a t u r a l vegetation (White, 1979). Even though the coas t a l f o r e s t s of Vancouver Island are uniquely imposing i n stature and age, they share a common feature with many other vegetation types (e.g. Grimm, 1984) i n that disturbance has played a major r o l e i n t h e i r development. In f a c t , continuous small or large scale disturbances may be e s s e n t i a l to t h e i r maintenance. 159 1. PSEUDOTSUGA COMMUNITY TYPES F i r e i s undoubtedly the most noticeable form of disturbance within the study area. It has permitted Pseudotsuga menziesii to remain the dominant tree species i n most community types of the d r i e r i n t e r i o r sector of the study area. Because of i t s thick bark, Pseudotsuga men- z i e s i i i s considered the most f i r e r e s i s t a n t of a l l coa s t a l tree species (Minore, 1979). However, i t s seedlings are incapable of e s t a b l i s h i n g themselves under the shade of i t s canopy, except perhaps i n the d r i e s t parts of co a s t a l B r i t i s h Columbia (Krajina, 1969; Krajina et a l . , 1982). Thus, the bell-shaped d i s t r i b u t i o n curves of Pseudotsuga menziesii stems i n most community types are c h a r a c t e r i s t i c of a s e r a i species ( Fig. 15) which depends e n t i r e l y on the occurrence of a major disturbance, f i r e i n th i s case, for i t s establishment. In the dry Pinus-Pseudotsuga forests (DI) of rock outcrops, the dry Pseudotsuga forests (PI), and the Pseudo- tsuga-Linnaea f o r e s t s (P3), the s e r a i r o l e of Pseudotsuga menziesii i s not as obvious because some regeneration appears to occur (Fig. 15). However, only on the rock outcrop communities (type DI) of the i n t e r i o r of the study area does Pseudotsuga's s i z e - c l a s s d i s t r i b u t i o n curve appear c h a r a c t e r i s t i c of a primary species ( Fig. 15). It has been suggested that Pseudotsuga menziesii cannot regenerate i n the moist coa s t a l f o r e s t s because i t s seedlings or saplings cannot transpire s u f f i c i e n t l y i n the shade to r i d themselves of excess moisture (Krajina, 1969; Krajina et a l . , 1982). Thus, Krajina (1969) argues that P_. menziesii becomes "shade t o l e r a n t " , or has the a b i l i t y to regenerate under a canopy, only on dry s i t e s near the Coast. Conversely, Tsuga 160 heterophylla requires shade to germinate on dry s i t e s , and even then the saplings or young trees w i l l l i k e l y die following a drought (Krajina, 1969). Viewed d i f f e r e n t l y , i t may be that Pseudotsuga menziesii i s the most shade tolerant of the tree species that can grow i n c l i m a t i c a l l y dry areas or edaphically dry s i t e s r o n Vancouver Island. Tsuga hetero- p h y l l a i s more shade tolerant, i n an absolute sense, than Pseudotsuga  menziesii, but i t i s probably incapable of surviving on the d r i e s t s i t e s , as observed by Krajina (1969). On such dry s i t e s (or areas), the r e l a -t i v e l y shade i n t o l e r a n t Pseudotsuga menziesii w i l l then become the dominant tree species, because i t i s the most shade tolerant of a l l the other species capable of growing there ( i . e . Arbutus menziesii, Pinus  contorta). This concept has been proposed by Daubenmire i n h i s habitat type approach to vegetation (Daubenmire and Daubenmire, 1968). In a l l community types of the Pseudotsuga group, except those of the d r i e s t environments (types Dl and PI), Tsuga heterophylla and Thuja p l i c a t a are c l e a r l y primary, or climax, species ( Fig. 15). Both are e a s i l y k i l l e d by f i r e s (Minore, 1979). Tsuga heterophylla seedlings are commonly found growing on unde-composed wood substrata on the f o r e s t f l o o r of Pseudotsuga community types (Table 32). In the community type where the r e l a t i o n s h i p was not s i g n i -f i c a n t , the mean seedling density was s t i l l the highest on the undecom-posed wood substrata (Table 32). Christy and Mack (1984) have shown that Tsuga heterophylla " j u v e n i l e s " are almost e x c l u s i v e l y r e s t r i c t e d to decaying logs, predominantly those i n intermediate stages of decomposition. These p a r t i a l l y decomposed "nurse logs" are regarded as presenting an optimal compromise of l i t t e r - s h e d d i n g c h a r a c t e r i s t i c s (best i n youngest 161 logs) and substratum conditions (best i n oldest logs) that permits the successful germination and establishment of tree seedlings (Christy and Mack, 1984). It i s assumed that l i t t e r accumulation represents an important impediment to the establishment of Tsuga heterophylla seedlings, and that the nurse logs provide the necessary elevated "safe s i t e s " (sensu Harper et a l . , 1965) within the community. Nurse logs with hundreds of Tsuga heterophylla seedlings and saplings were frequently observed within the Pseudotsuga group. In Tsuga-Pseudotsuga-Polystichum forests (P5), seedlings, saplings and small Tsuga heterophylla trees were often seen growing on or very near the bases of the large Pseudotsuga menziesii dominants. This l o c a t i o n may be the only place free from l i t t e r i n forests where logs are rare. Pseudotsuga menziesii seedlings are not s t a t i s t i -c a l l y associated with a p a r t i c u l a r substratum (Table 32), but t h i s could be an a r t i f a c t of the very low seedling d e n s i t i e s encountered under the dense canopy of the community types analyzed. Tsuga heterophylla occurs i n i n c r e a s i n g l y larger s i z e - c l a s s e s along a moisture gradient within the Pseudotsuga group (community types P3 < P4 < P5 = P6, F i g . 15). In the cool and moist conditions of the montane Tsuga forests (P6), Tsuga heterophylla probably grows as f a s t as Pseudotsuga  menziesii following a disturbance, and may thus be a good species for r e f o r e s t a t i o n , either alone or i n mixture with Pseudotsuga menziesii. This may be p a r t i c u l a r l y advantageous i f a r e l a t i v e l y short planting to harvest r o t a t i o n i s planned (80 to 100 years); otherwise, the superior, long-term s i z e p o t e n t i a l of Pseudotsuga menziesii negates the use of Tsuga heterophylla. On the poor and shallow s o i l s of the montane Tsuga-Gaultheria f o r e s t s (P7), Tsuga heterophylla may also be the most appropriate 162 choice for r e f o r e s t a t i o n . In a l l other community types at lower e l e -vations (PI, P2, P3, P4 and P5), Pseudotsuga menziesii would appear to be the most i d e a l l y suited species for r e f o r e s t a t i o n . The frequency of droughts causing mortality would preclude any use of Tsuga heterophylla as a v i a b l e r e f o r e s t a t i o n species i n most of these community types, p a r t i -c u l a r l y those with the d r i e s t moisture regimes (PI and P3). The Pseudo- tsuga-Thuj a-Acer forests (P2) are the only community type within the Pseudotsuga group which has more Thuja p l i c a t a stems per hectare than Tsuga heterophylla stems (Fig. 15). The hypothesized presence of s o i l seepage would also explain t h i s discrepancy. Tsuga heterophylla regene-r a t i o n i s reportedly poor i n these nutrient r i c h s i t e s , occurring only on decaying wood; conversely, Thuja p l i c a t a does w e l l i n the same s i t e s (Krajina, 1969). The double peaks i n the s i z e - c l a s s d i s t r i b u t i o n curve of Pseudo- tsuga menziesii within the Pseudotsuga-Thuja-Acer forests (P2) are i n t e r -preted as r e s u l t i n g from two periods of establishment, following two d i s t i n c t f o rest f i r e s ( F ig. 15). The close geographical proximity of a l l the plo t s permits such an explanation, since t h e i r f i r e disturbance h i s t o r y may be assumed to be i d e n t i c a l . F i r e s usually occur on a r e l a -t i v e l y large scale i n coastal f o r e s t s , but with a low frequency of once every few hundred years. Indirect evidence of t h i s i s found i n the dominance of vast areas by Pseudotsuga menziesii, a species which can e s t a b l i s h quickly i n openings cleared by f i r e , as w e l l as avoid damage from surface f i r e s because of the thick, f i r e r e s i s t a n t bark of mature trees (Minore, 1979). H i s t o r i c a l l y , large conflagrations were l i k e l y i n the heavy f u e l loads of coa s t a l forests following periods of unusually 163 hot and dry weather. A recent forest f i r e , fought without much success with modern equipment and techniques, burned almost the e n t i r e south-facing slopes of the Sproat Lake v a l l e y . This example provides an i n d i c a t i o n of the minimum are a l extent of forest f i r e s which have occurred i n the d r i e r c o a s t a l areas of B r i t i s h Columbia. An a l t e r n a t i v e to the two f i r e s hypotheses i s that a l l Pseudotsuga  menziesii trees belong to the same cohort i n which a si z e hierarchy has developed through i n t r a s p e c i f i c competition (Harper, 1977). When such a hierarchy of sizes i s created through competition however, the smaller i n d i v i d u a l s are always more numerous. This i s not supported by the data i n F i g . 15 and the competition hypothesis i s therefore rejected. More l i k e l y , the second f i r e following which the smaller ( i . e . younger) Pseudotsuga trees got established, was of a l i g h t e r i n t e n s i t y than the f i r s t burn. Many already established Pseudotsuga trees would have survived the second f i r e , while almost a l l trees of other species would have been k i l l e d . A l l the larger Pseudotsuga menziesii trees found i n p l o t s of the Pseudotsuga-Thuja-Acer forests (P2) have f i r e charred bark. A s u f f i c i e n t l y large sample of increment cores from the Pseudotsuga menziesii population of the area would permit the v a l i d a t i o n of the two f i r e s hypothesis. 164 2. THUJA COMMUNITY TYPES Wind disturbance, causing major blowdowns over large areas or the i s o l a t e d f a l l i n g of s i n g l e trees, i s regarded as the second most prevalent type of forest disturbance within the study area. Wind r e l a t e d e f f e c t s increase towards the coast where the forests are more d i r e c t l y exposed to storms. Large scale blowdown i s probably the major factor i n i t i a t i n g secondary forest succession on the coast, as forest f i r e s are believed to be extremely rare. The prevalence and extent of wind disturbance also appears to be linked with elevation. Extensive blowdowns are most frequently observed on the ridges or summits of mountains nearest to the coast (e.g. p l o t 151, F i g s . 1 and 9), where the montane Tsuga-Abies forests (A3) are usually found. In v a l l e y s or on p l a i n s c l o s e r to sea l e v e l , where the coastal Thuj a forests (T4) predominate, i s o l a t e d tree f a l l s triggered by wind tend to be the most frequent form of disturbance. Landslides also influence the development of some coastal community types, but t h e i r frequency and a r e a l extent are small. The bare areas with improved drainage created by l a n d s l i d e s would be r a p i d l y colonized by l i g h t demanding or fast growing species such as Pseudotsuga menziesii and Picea s i t c h e n s i s . Apart from rock outcrops, old la n d s l i d e s appear to be the only s u i t a b l e environment for Pseudotsuga meriziesii near the coast. Plot 87 on the upper-slope of the Cypre River v a l l e y and p l o t 155 on upper-slopes near Kennedy Lake are examples of such s i t e s . Picea  s i t c h e n s i s also occurs on old l a n d s l i d e s near the coast, but only at the base of slopes where moisture and nutrient l e v e l s are probably higher (plots 91 and 69). 165 Daubenmire and Daubenmire (1968; p. 55) have summarized an obser-vation common to a l l who have studied forests dominated by Thuja p l i c a t a : "Thuja p l i c a t a i s d i s t i n c t i v e from the other trees i n that younger age-classes often seem inadequate to guarantee replacement of larger i n d i -v i d u a l s . . . " . This can be seen i n the coastal montane Thuja forests (T3) and the coastal Thuja forests (T4), where the s i z e - c l a s s d i s t r i b u t i o n curve of Thuja p l i c a t a dips far below the curves of Tsuga heterophylla and Abies amabilis i n the smaller s i z e - c l a s s e s , but extends much further into the larger s i z e - c l a s s e s (Fig. 16). Daubenmire and Daubenmire (1968) have suggested that the longevity of i n d i v i d u a l s and the l a y e r i n g habit of Thuja p l i c a t a were probably a key to understanding i t s persistence. Each i n d i v i d u a l needs only to leave one s u c c e s s f u l l o f f s p r i n g to maintain the population density, "thus, the longer i t l i v e s , the more sparse the reproduction can be and yet s u f f i c e " (Daubenmire and Daubenmire, 1968; p. 55). Indeed, Thuja p l i c a t a has a p o t e n t i a l longevity of over 1,000 years, at l e a s t double that of the co-dominants Tsuga heterophylla and Abies amabilis (Waring and F r a n k l i n , 1979). If l a y e r i n g does occur, the longevity of the "genetic" i n d i v i d u a l may be much longer. The c o a s t a l Thuja forests (T4) may thus represent an i d e a l example of Connell and Slatyer's (1977) i n h i b i t i o n model, where the largest and longest-lived species eventually achieves dominance as succession proceeds. Young coastal forests developing a f t e r extensive wind damage, however, are strongly dominated by Tsuga heterophylla and Abies amabilis (e.g. p l o t 151). Also, the coastal Tsuga-Blechnum-Polystichum forests (T2), which are suspected of having had a large disturbance at t h e i r o r i g i n , have very l i t t l e Thuja p l i c a t a (Table 24). In most plo t s of the coastal Thuj a 166 forests (T4), where Thuja p l i c a t a i s the f i r s t dominant, no important disturbance could be detected, and i t i s possible that such stands have had no major disturbance i n several hundreds, i f not thousands of years. Thuja p l i c a t a ' s dominance i n the low elevation coastal areas would be threatened i f i t s trees, otherwise l o n g - l i v e d , were frequently f e l l e d or f a t a l l y damaged by wind, bef ore the time necessary for th e i r successful regeneration. Thus, two hypotheses can be put forward to explain the presence of apparently stable Thuja p l i c a t a communities near the coast : the f i r s t states that strong winds very r a r e l y occur i n areas where Thuja  p l i c a t a i s the present dominant; the second states that Thuja p l i c a t a i s less susceptible than other tree species to wind damage. The f i r s t hypo-tehsis appears untenable, because strong winds occasionally do occur even at low elevations near the coast. On the other hand, several l i n e s of circu m s t a n t i a l evidence appear to support the second hypothesis. Thuja  p l i c a t a i s indeed considered the most wind r e s i s t a n t coastal tree, a f t e r Pseudotsuga menziesii, possibly because of i t s very dense and extensive root system (Minore, 1979; Klinka and F e l l e r , 1984). Some mechanical resistance to wind-toppling may also be gained by the fl u t e d and buttressed bases of large Thuja p l i c a t a trees (Putz et a l . , 1983). Also, mechanical resistance to bole snapping by wind may be increased by the fac t that the trunks of old Thuja p l i c a t a trees are almost always hollow, perhaps con-f e r r i n g the enhanced stress r e s i s t i n g c h a r a c t e r i s t i c s of hollow c y l i n d e r s . Some evidence for a superior resistance to wind by large Thuja p l i c a t a trees was found i n several p l o t s . For example i n p l o t 72, large i n d i -v iduals of Thuja p l i c a t a were observed s t i l l standing while almost a l l Tsuga heterophylla and Abies amabilis trees had been blown down i n 167 approximately the same d i r e c t i o n , apparently during the same storm. Large Thuja p l i c a t a trees may be able to lose t h e i r leader and uppermost branches during storms without f a t a l consequences, p a r t l y because of a high resistance to rot-causing fungi and to insect attack (Minore, 1979). The so c a l l e d "candelabra" appearance of large Thuja trees near the coast, seems to be caused by the death of the leader and upper-crown branches, and by the shared a p i c a l dominance of several large l a t e r a l branches. This p a r t i c u l a r candelabra shape has not been noticed i n Thuja p l i c a t a trees elsewhere than i n the wettest areas nearest to the coast. This shape may develop with increasing age of the i n d i v i d u a l s ; however, ancient Thuja trees can be found, i n moist pockets even i n the d r i e s t and most f i r e prone areas, that do not possess the c h a r a c t e r i s t i c candelabra shape. The p o s s i b i l i t y of a d i s t i n c t genetic race, r e s t r i c t e d to a narrow coa s t a l band, seems to be discounted by the high genetic uniformity of Thuja p l i c a t a (Copes, 1981). The most l i k e l y explanation i s that a p a r t i c u l a r set of environmental factors (abundant moisture, mild temperatures, occasional strong winds, lack of f i r e ) combine with the genetic charac-t e r i s t i c s of the species (resistance to rot and i n s e c t s , weak a p i c a l dominance, longevity) to produce the observed candelabra shape i n old Thuja p l i c a t a trees near the coast. Germination and establishment s i t e s for seedlings appear to be almost e n t i r e l y r e s t r i c t e d to undecomposed wood substrata, mostly large logs, i n the Thuja group (T2, T3 and T4, Table 32). These logs represent "safe s i t e s " with p a r t i c u l a r combinations of e c o l o g i c a l factors ( a b i o t i c and b i o t i c ) which permit the successful germination of seeds and e s t a b l i s h -ment of seedlings (Harper et a l . , 1965). It has been frequently observed 168 that Tsuga heterophylla and Thuja p l i c a t a regenerate on f a l l e n trees, or "nurse logs", i n coastal forests (Franklin and Dyrness, 1973). Both of these species have small seeds, producing small and f r a g i l e seedlings that are l i k e l y to be susceptible to mechanical damage by b u r i a l . Abies  amabilis, on the other hand, has larger seeds and produces large, robust seedlings (Schopmeyer, 1974), which are not expected to be as strongly affected by l i t t e r accumulation. This could explain why the d i s t r i b u t i o n of Abies amabilis seedlings i s unrelated to the occurrence of undecom-posed wood i n most of the community types analyzed (Table 32). The impor-tance of undecomposed wood for the germination and establishment of Thuja p l i c a t a seedlings can be seen i n the eighteen-fold increase i n the number of seedlings found on undecomposed wood compared to f o r e s t f l o o r s i t e s i n Thuja forests (T3 and T4, Table 32). Thuja p l i c a t a logs may provide the " s a f e s t " s i t e s for seedling establishment and development to maturity. The decay rate of Thuja p l i c a t a logs appears to be extremely slow, compared to that of Abies amabilis and Tsuga heterophylla logs (Foster and Lang, 1982; Graham, 1981). Abies amabilis appeared to have the fa s t e s t decay rate i n the f i e l d ; i t i s probably comparable to the decay rate of Abies balsamea (Foster and Lang, 1982). The discovery, i n p l o t 73, of a large Thuja p l i c a t a tree, approximately 400 years old by a growth-ring count, growing on top of a Thuja log of s i m i l a r s i z e i l l u s t r a t e s the slow decay rate of Thuja p l i c a t a . Indeed, t h i s log was s t i l l sound and not i n contact with the s o i l along some of i t s length. Where systematic obser-vations were made (some p l o t s of the coastal Thuja f o r e s t s ) , i t was found that almost a l l seedlings, saplings and young trees of Thuja p l i c a t a and Tsuga heterophylla were rooted on decaying f a l l e n trees, stumps or even 169 on the bases of l i v i n g trees. This was not as obvious f o r larger and older trees, whose nurse logs may have had eventually rotted away. The fourth hypothesis stated i n the Introduction, that Thuja p l i c a t a i s able to maintain i t s e l f i n a l l of the coa s t a l forests i t presently dominates, appears very p l a u s i b l e . The extent to which vegetative rege-neration of Thuja p l i c a t a contributes towards i t s t o t a l regeneration remains to be assessed. Schmidt (1955) reported that vegetative regene-r a t i o n might be as important as regeneration from seed i n high density stands. Vegetative regeneration may occur through the layering of low branches pinned under l i t t e r , from the rooting of broken l i v e branches, or f a l l e n l i v e boles (Schmidt, 1955). Such occurrences were not observed i n the coa s t a l montane Thuja f o r e s t s (T3), or i n the coa s t a l Thuja forests (T4). Reforestation within the community types of the Thuja group can be e f f e c t i v e l y c a r r i e d out using several species. For short rotations on productive s i t e s (T2 > T3 > T4), both Tsuga heterophylla and Abies ama- b i l i s could be recommended, with perhaps some Picea s i t c h e n s i s only on the best s i t e s . Pseudotsuga menziesii cannot be recommended as a v i a b l e r e f o r e s t a t i o n species i n the area occupied by the Thuja vegetation group (Spiers e_t a l . , 1983; Carter et a l . , 1984). The s i t e s near the coast where t h i s species appears to grow s u c c e s s f u l l y are very l i m i t e d . On the poorest s i t e s (TI and T5), the best growth might be acheived by Thuja  p l i c a t a , or by the f a s t e r growing Pinus contorta. Thuja p l i c a t a repre-sents the climax species i n dry (D2, TI) as w e l l as wet (T5) n u t r i e n t -poor s i t e s (Fig. 16). D e f i n i t e l y s e r a i i n the coastal wet Thuja forests 170 (T5), Pinus contorta may be capable of self-regeneration i n the very open, coastal dry Pinus forests (D2) (Fig. 16). The presence of understory fern species could serve as u s e f u l i n d i c a t o r s of s i t e p r o d u c t i v i t y near the coast. Polystichum munitum was most abundant i n productive s i t e s where access to mineral s o i l was not r e s t r i c t e d by thick organic horizons. Conversely, Blechnum spicant dominates on thick organic horizons found on the l e s s productive s i t e s . 171 3. ABIES COMMUNITY TYPES Because of i t s high shade tolerance, large seed s i z e , and capa-b i l i t y to withstand long periods of suppression under a forest canopy, Abies amabilis i s considered a climax or primary species. It has t h i s r o l e i n a l l of the community types within the Abies group (except for type A7) and i n many within the Thuja group (Figs. 16 and 17). The importance of disturbance i n producing the tree s i z e - c l a s s structures of community types within the Abies group can be i n f e r r e d from the i r r e g u l a r shapes of the d i s t r i b u t i o n curves shown i n F i g . 17. For example, community type A3 i s found on mountain ridges near the coast, where wind disturbance appears to maintain a two-tiered arborescent structure. This i s characterized by a-lower layer of suppressed trees and saplings and a highly discontinous upper layer c o n s i s t i n g of trees released from competition a f t e r the l a s t wind disturbance. This p a r t i -cular forest structure was also observed by Klinka e_t al_. (1979), and i t s o r i g i n may be s i m i l a r to the wind driven wave-regeneration phenomenon described for high elevation Abies balsamea fo r e s t s of the northeastern United States (Sprugel and Bormann, 1981). A s i m i l a r i n t e r p r e t a t i o n could be made for the montane Abies-Tsuga forests (A2). The c o a s t a l Tsuga-Blechnum-Polystichum forests (T2) have a s i z e -class structure which i s also heavily skewed towards the larger s i z e -classes (Fig. 17). Landslide disturbance i s suspected to have been at the o r i g i n of at l e a s t h a l f of the stands of t h i s community type, and evidence of wind disturbance was found i n the remaining stands. I t could be argued that the coa s t a l Tsuga-Blechnum-Polystichum forests (T2) are 172 a c t u a l l y long-duration s e r a i communities which occur near the coast a f t e r major disturbances have improved seedling establishment conditions, s o i l drainage or s o i l nutrient a v a i l a b i l i t y . The slow accumulation of organic matter on the forest f l o o r of these communities may eventually d i r e c t t h e i r development towards community types dominated by Thuja p l i c a t a (T3 or T4). This hypothetical successional sequence may never be e n t i r e l y completed on old landsl i d e s because of the profound modification of the s i t e drainage. The Tsuga-Blechnum-Polystichum forests (A7) show evidence of past disturbance i n the form of landsl i d e s i n the two co a s t a l p l o t s , and f i r e i n the inland p l o t s . The shape of the s i z e - c l a s s d i s t r i b u t i o n curve of Tsuga heterophylla, c h a r a c t e r i s t i c of a climax species (Fig. 17), and the small importance of s e r a i species (Table 26), may suggest that the o r i g i n a l disturbances are very o l d . A l t e r n a t i v e l y , i t i s possible that Tsuga hete- r o p h y l l a , because of p a r t i c u l a r environmental conditions, established i t s e l f with more success than the usual s e r a i species following the disturbance. The montane Abies-Streptopus f o r e s t s (A4) and the lowland Abies forests (A5) not only have f l o r i s t i c s i m i l a r i t i e s , but are also s i m i l a r i n tree s i z e - c l a s s structure ( F i g . 17). Abies amabilis has a s i z e - c l a s s d i s t r i b u t i o n curve c h a r a c t e r i s t i c of a primary species i n both community types, whereas Tsuga heterophylla's s i z e - c l a s s d i s t r i b u t i o n curve has a peak i n the larger s i z e - classes ( F i g . 17). The occurrence of past disturbances was not frequently recorded i n these community types, except for the occasional tree blown down by wind. In f a c t , p a r t l y decayed, 173 standing dead tree boles were often observed. The r o l e of Tsuga hetero-p h y l l a , i n these two community types, may be that of an opportunistic, gap-regenerator which invades openings following the removal of a large canopy tree. In the montane Tsuga-Abies-Gaultheria forests ( A l ) , f i r e has been the major type of disturbance, as confirmed by the presence of Pseudotsuga  menziesii with i t s c h a r a c t e r i s t i c a l l y s e r a i s i z e - c l a s s d i s t r i b u t i o n curve ( F i g . 17). For r e f o r e s t a t i o n purposes within the Abies group, Abies amabilis and Tsuga heterophylla may be equally appropriate i n most of the montane community types (A2, A3 and A4), and i n the lowland Abies f o r e s t s (A5). Pseudotsuga menziesii could represent a v i a b l e species f o r the montane Tsuga-Abies-Gaultheria f o r e s t s (Al) and some inland stands of the Tsuga- Blechnum-Polys tichum forests (A7). Coastal stands of the same community type would be excellent s i t e s for Picea s i t c h e n s i s . 174 4. FLOODPLAIN COMMUNITY TYPES The dynamics of the f l o o d p l a i n communities sampled i n th i s study appear to correspond generally to previous accounts by Cordes (1972) f o r Vancouver Island and by Fonda (1974) for the Olympic Peninsula. Very young floodplains dominated by Alnus rubra (Fonda, 1974) were not sampled, but they were frequently observed along a l l major r i v e r s . The youngest stand sampled i s probably pl o t 171, near the Klanawa River. This p l o t consisted of a dense grove of Picea s i t c h e n s i s with a shrubless under-story nearly completely covered by Polystichum muniturn. Further away from the edge of the Klanawa River, p l o t 170 occupies an older, l e s s frequently inundated f l o o d p l a i n . Here, Tsuga heterophylla was more abun-dant than Picea s i t c h e n s i s i n the tree stratum. In in c r e a s i n g l y older f l o o d p l a i n s , only a few large Picea s i t c h e n s i s i n d i v i d u a l s remain. Tree species regeneration occurs almost e x c l u s i v e l y on Picea logs, and i s dominated by Tsuga heterophylla (Tables 24 and 32). Again, the f a l l e n logs provide safe s i t e s against b u r i a l by l i t t e r and mechanical damage during floods. The canopy of the older stands i s always sparse, which probably explains the presence of an extremely dense and t a l l shrub layer, dominated by Rubus s p e c t a b i l i s and Ribes bracteosum. In the Olympic Peninsula such an extensive shrub layer never develops (Fonda, 1974), possibly because of a strong browsing pressure by elk. The large sizes of trees of d i f f e r e n t species growing on fl o o d -p l a i n s indicates the high growth p o t e n t i a l of these habitats (Table 24). Some of the largest Pseudotsuga menziesii trees encountered during the study (181 cm DBH) were found on an old f l o o d p l a i n situated near Nahmint 175 Lake (plot 122). Thus, since environmental factors on floodplains may be considered to be non-limiting (except perhaps tolerance to f l o o d i n g ) , the o r i g i n a l tree species composition i s l i k e l y to depend mainly on stochastic events, such as seed d i s p e r s a l or the a v a i l a b i l i t y of l o c a l seed sources, when a major disturbance releases a f l o o d p l a i n for c o l o n i -zation. Fast growing trees which can e x p l o i t f u l l y the i d e a l growth con-d i t i o n s of floodplains should be selected for r e f o r e s t a t i o n . Picea  s i t c h e n s i s probably remains the best suited species on a l l s i t e s , but Pseudotsuga menziesii may be an a l t e r n a t i v e choice on older f l o o d p l a i n terraces i n the i n t e r i o r of the study area. 176 CHAPTER 6. CONCLUSIONS The analysis of vegetation-environment r e l a t i o n s h i p s i n old-growth forests of a large sector of the west coast of Vancouver Island was the prime objective of t h i s study. Macro-climate appears to have the strongest influence on vegetation over the whole study area; v a r i a t i o n i n s o i l parent material i s ranked second i n importance. Within areas of r e l a -t i v e l y uniform macro-climate and s o i l parent material, stronger r e l a t i o n -ships with other environmental factors were found. In the Pseudotsuga group, c h a r a c t e r i s t i c of the d r i e r inland section of the study area, vegetation i s correlated with meso-climate (elevation) and s o i l moisture gradients. Large scale f i r e disturbances have played a major r o l e i n the determination of the vegetation compo-s i t i o n and structure i n t h i s group. Also, homogeneity of the vegetation, between environmentally s i m i l a r s i t e s , was generally the highest i n areas where f i r e disturbance was absent or infrequent, as i n the Thuja group. However, d i f f e r e n t trends were observed for i n d i v i d u a l vegetation s t r a t a . The herb and shrub s t r a t a increased i n homogeneity with decreasing f i r e disturbance, but the opposite trend was observed i n the tree l a y e r . This trend i s linked to the presence of very homogeneous, almost mono-s p e c i f i c , p o s t - f i r e stands dominated by Pseudotsuga menziesii. The Thuja group, found e x c l u s i v e l y near the coast, displays v a r i a t i o n mainly along gradients of s o i l n u t r i e n t s and meso-climate 177 (elevation). The importance of s o i l n utrients i s probably re l a t e d to the large v a r i a b i l i t y i n parent material found i n the Thuja group. Moreover, the extremely abundant p r e c i p i t a t i o n probably explains the absence of a major s o i l moisture gradient. The longevity of Thuja p l i c a t a , and i t s apparently high resistance to wind damage, are features thought to be important i n maintaining the high dominance of t h i s species i n forests nearest to the coast. The Abies group was found over a range of coastal and more inland s i t e s ; thus, a f f i n i t i e s with macro-climate were d i f f i c u l t to deduce. Vegetation appeared mainly r e l a t e d to meso-climate (elevation) and s o i l moisture gradients. The cool, moist micro-climates associated with several community types within the Abies group may have n u l l i f i e d the influence of macro-climate. Alpha and beta d i v e r s i t y were found to increase towards the i n t e r i o r of the study area. These d i v e r s i t y increases may be caused by the increasing amount of heat a v a i l a b l e f or plant growth, by the decreasing p r o d u c t i v i t y brought on by moisture d e f i c i t s , by the increasing frequency and s e v e r i t y of large scale f i r e disturbances, or, most l i k e l y , by a combination of a l l of these f a c t o r s . Analyses of tree species s i z e - c l a s s d i s t r i b u t i o n s confirm the e s s e n t i a l l y s e r a i r o l e of Pseudotsuga menziesii i n most community types, while Tsuga heterophylla, Abies amabilis and Thuja p l i c a t a are the major p o t e n t i a l "climax" species. The eventual dominance of a p a r t i c u l a r species, or combination of species, i s linked to a complex i n t e r p l a y of disturbance regime and e c o l o g i c a l s i t e c h a r a c t e r i s t i c s . 178 F i n a l l y , a gradient analysis approach to resource inventory and management may represent an advantage over more t r a d i t i o n a l methods, i n i t s r e l a t i v e freedom from resource mapping and complex i n t e g r a t i o n of diverse resource maps. The vegetation patterns of a sector can instead be modelled through multiple regression equations using a few ec o l o g i c a l f a c t o r s , previously i d e n t i f i e d as strongly linked to vegetation v a r i a t i o n . This information would then form a useful basis for forest management decisions bearing on harvesting, post-harvesting treatments, and species s e l e c t i o n for r e f o r e s t a t i o n . The s e l e c t i o n of appropriate tree species for r e f o r e s t a t i o n i s one of the most important steps i n forest management. Within the area studied, i t appears that Pseudotsuga menziesii constitutes the most appropriate choice i n many s i t u a t i o n s . Possible exceptions are high elevation and nutrient poor s i t e s where other species, such as Tsuga  heterophylla, may grow as fa s t or f a s t e r . However, r e f o r e s t a t i o n with Pseudotsuga menziesii on coastal s i t e s , within the area occupied by the Thuja group, should be s t r i c t l y avoided because of severe growth problems, l i k e l y caused by arsenic accumulation. Integral conservation of p a r t i c u l a r s i t e s or areas also should be part of a comprehensive and e c o l o g i c a l forest management program. As forest management techniques develop, intensive management w i l l be inc r e a s i n g l y directed towards the most productive s i t e s , with easiest access and gentle t e r r a i n . This represents a desirable trend i f i t allows forests to be used as a t r u l y renewable resource, with better r e f o r e s t a t i o n , control of s o i l erosion and minimal nutrient l o s s . As a 179 r e s u l t , less logging pressure should be f e l t by les s productive s i t e s . Already, s i t e s characterized as unproductive, such as rock outcrops, very steep slopes and some high elevation s i t e s , are neglected i n most logging operations. These s i t e s are p a r t i c u l a r l y suited for i n t e g r a l conservation; they are r i c h i n species, usually occur at the extremeties of e c o l o g i c a l gradients, and therefore represent i d e a l s i t e s for the conservation of genetic v a r i a t i o n (e.g. community types Dl, D2, P7, TI, T5 and A l ) . The maintenance of genetic d i v e r s i t y within populations of economically valuable tree species i s a duty of the forest industry and of the relevant governmental agencies. Thus, through the conservation of p a r t i c u l a r habitats, or e n t i r e areas, the forest industry could contribute towards t h i s goal. Another e c o l o g i c a l aspect of importance to forest management i s the prevalence of natural f i r e disturbance i n the i n t e r i o r sector of the study area, and i t s v i r t u a l absence i n the coastal sector. Therefore, the use of f i r e as a forest management t o o l may recreate n a t u r a l l y occurring phenomena i n the Pseudotsuga f o r e s t s , to which the b i o t a i s adapted, but unexpected e c o l o g i c a l problems may be created i n Thuja forests near the coast, where nutrient c y c l i n g appears to occur mostly within organic s o i l horizons, which may be p a r t l y or t o t a l l y destroyed during burns. 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Ecology 56 : 771-790. Whittaker, R.H., and G.M. Woodwell, 1978. Retrogression and coenocline distance. In "Ordination of Plant Communities", R.H. Whittaker (ed.), pp. 51-70, W. Junk, The Hague. Williams, B.K., 1983. Some observations on the use of discriminant analysis i n ecology. Ecology 64 : 1283-1291. 191 Table 1 : L i s t of environmental v a r i a b l e s . I. TOPOGRAPHIC 1. 2. 3. 4. elevation (m) aspects (0-180°, NNE to SSW) slope (%) p o s i t i o n 1 - cr e s t 2 - upper-slope 3 - mid-slope 4 - lower-slope 5 - l e v e l 6 - depression I I . EDAPHIC II. (a) p h y s i c a l 5. drainage : 1 - very rapid 2 - rapid 3 - well 4 - moderately well 5 - imperfect 6 - poor 7 - very poor e f f e c t i v e rooting depth (cm) root r e s t r i c t i n g depth (cm) s o i l depth (cm) material : 0 - rock 1 - c o l l u v i a l 2 - morainal 3 - f l u v i a l 4 - a l l u v i a l LFH tickness (cm) B i % coarse fragments B i texture 6. 7. 8. 9. 10. 11. 12. 13. 14. EDAPHIC (b) chemical 16. LFH pH (H 20) 17. LFH pH (CaCl 2) 18. LFH % C 19. LFH % N 20. LFH C/N 21. A pH (H 20) 22. A pH (CaCl 2) 23. Bx pH (H 20) 24. B x pH (CaCl 2) 25. B i % C 26. B i % N 27. Bx C/N 28. B 2 pH (H 20) 29. B 2 pH (CaCl 2) I I I . GEOGRAPHIC 1 - sand 30. distance 2 - loamy sand 3 - sandy loam 4 - loam IV. DISTURBANCE 5 - sandy clay loam 6 - s i l t loam 31. f i r e : 0 7 - s i l t 1 8 - sandy clay 9 - clay loam 32. wind : 0 10 - s i l t y clay loam 1 11 - s i l t y clay 12 - clay no evidence charcoal or scars no evidence blowdowns V6/V7 V6/V8 15. V10/V6 \ 192 Table 2 : L i s t of community c h a r a c t e r i s t i c s . I. RICHNESS 1. tree species 2. shrub species 3. herb species 4. bryophyte and l i c h e n species 5. understory vascular species 6. vascular species 7. t o t a l species I I . COVERAGE (%) 8. understory s t r a t a 9. shrub stratum 10. herb stratum 11. bryophyte and l i c h e n stratum I I I . TREE STRATUM 12. tree basal area (m2/ha) 13. tree density (stems/ha) 14. maximum tree height (m) 193 Table 3 : Species with the ten largest c o e f f i c i e n t s on axes one and ordination of the 172 p l o t s . p o s i t i v e and negative eigenvector two of the r e c i p r o c a l averaging Axis 1 (% variance = 11.0) Pinus contorta (sap.) .387 Abies amabilis (tree) -.168 P. contorta (tree) .384 A. amabilis (sap.) -.138 Pseudotsuga menziesii (seed.) .330 A. amabilis (seed.) -.126 P. menziesii (sap.) .217 Tsuga heterophylla (seed.) -.123 Acer macrophyllum (seed.) .179 T. heterophylla (tree) -.110 P. menziesii (tree) .177 Vaccinium alaskaense -.106 Arbutus menziesii (tree) .163 T. heterophylla (sap.) -.099 P. contorta (seed.) .162 Blechnum spicant -.098 Rhacomitrium lanuginosum .157 Rubus pedatus -.065 Vaccinium ovatum .155 Picea s i t c h e n s i s (tree) -.055 Axis 2 (% variance - 8.8) Abies amabilis (sap.) .301 Picea s i t c h e n s i s (tree) -.351 A. amabilis (tree) .192 P. s i t c h e n s i s (seed.) -.346 A. amabilis (seed.) .190 Rubus s p e c t a b i l i s -.276 Vaccinium alaskaense .172 Ribes bracteosum -.222 Rhytidiopsis robusta .157 Polystichum munitum -.212 Tsuga mertensiana (tree) .143 Athyrium f i l i x - f e m i n a -.158 Chamaecyparis nootkatensis (sap.) .127 Rubus p a r v i f l o r u s -.154 C. nootkatensis (tree) .110 Trautv e t t e r i a c a r o l i n e n s i s -.149 P. contorta (tree) .104 Sambucus racemosa -.142 Rubus pedatus .094 A. macrophyllum (sap.) -.131 194 Table 4 : Product moment co r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the 172 plo t s (n = 172; ** = p .01; * = .01 < p « .05). axis 1 axis 2 axis 2 -.279** -elevation -.347** .656** aspect .299** -.100 p o s i t i o n -.269** - .299** drainage -.386** -.014 s o i l depth -.279** - .036 material -.213** -.205** LFH pH (H 20) .292** -.413** LFH pH (CaCl 2) .331** -.432** LFH thickness -.293** .180* LFH % N -.231** .051 LFH C/N .244** .007 Bi pH (H 20) .039 -.215** Bi pH (CaCl 2) .023 -.202** Bi % coarse fragments .235** .201 e f f e c t i v e rooting depth .158* -.199** e f f . r . d . / s o i l depth .453** -.123 LFH t h i c k . / e f f . r. d. -.257** .212** f i r e disturbance .301** -.087 tree spp. richness .304** .005 shrub spp. richness .247** - .219** understory coverage .129 -.218** herb coverage -.150* -.254** bryo. coverage .408** - .102 tree basal area -.205** -.264** tree height -.191* - .240** 195 Table 5 : Species with the ten largest c o e f f i c i e n t s on axes one and ordination of the 140 p l o t s . p o s i t i v e and negative eigenvector two of the r e c i p r o c a l averaging Axis 1 (% variance = 13.6) Pseudotsuga menziesii (tree) .339 Abies amabilis (sap.) -.361 P. menziesii (seed.) .238 A. amabilis (tree) -.336 Acer macrophyllum (sap.) .221 A. amabilis (seed.) -.266 Cornus n u t t a l l i i (sap.) .188 Vaccinium alaskaense -.190 Hylocomium splendens .187 Rubus pedatus -.169 C. n u t t a l l i i (seed.) .173 Blechnum spicant -.139 A. macrophyllum (seed.) .169 Plagiothecium undulatum -.089 Berberis nervosa .150 Streptopus streptopoides -.087 Linnaea b o r e a l i s .146 Rhizomnium glabrescens -.072 Thuja p l i c a t a (sap.) .133 Rhytidiadelphus loreus -.072 Axis 2 (% variance = 9.8) Gaultheria shallon .333 Abies amabilis (seed.) -.223 T. p l i c a t a (seed.) .310 A. amabilis (tree) -.216 Vaccinium ovatum .285 A. amabilis (sap.) -.190 Blechnum spicant .277 P. menziesii (tree) -.181 T. p l i c a t a (tree) .275 Rubus pedatus -.157 T. p l i c a t a (sap.) .239 A. macrophyllum -.145 Pinus contorta (tree) .142 C. n u t t a l l i i (sap.) -.136 Carex obnupta .138 C. n u t t a l l i i (seed.) -.113 Pyrus fusca .114 Polystichum munitum -.110 Cornus canadensis .102 A. macrophyllum (seed.) -.110 196 Table 6 : Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the 140 p l o t s (n = 140; ** = p < .01; * = .01 < p <g .05). axis 1 axis 2 axis 2 -.408* -elevation -.005 -.496** aspect .290** -.140 slope .182* -.307** drainage -.532** .469** material -.300** .356** LFH pH (H 20) .240** .116 LFH pH (CaCl 2) .311** .084 LFH thickness -.483** .358** LFH % N -.314** .061 LFH C/N .252** -.135 Bi % coarse fragments .372** -.345** B 1 % C -.252** .112 B i % N -.316** .118 e f f e c t i v e rooting depth .395** -.285** root r e s t r i c t i n g depth .213* -.264** e f f . r . d . / s o i l depth .513** -.230** LFH t h i c k . / e f f . r. d. -.537** .388** f i r e disturbance .578** -.441** wind disturbance -.437** ,591** distance from coast .501** -.728** tree spp. richness .268** -.020 shrub spp. richness -.050 .223** herb spp. richness .217** -.436** bryo. spp. richness -.198** .231** vascular spp. richness .208* -.310** understory coverage -.153 .456** shrub coverage -.236** .463** herb coverage -.254** .363** bryo. coverage .360** -.075 tree height .225** -.472** 197 Table 7 : Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the Pseudotsuga group. Axis 1 (% variance = 14.4) Tsuga heterophylla (sap.) ,265 Acer macrophyllum (sap.) -.378 T. heterophylla (seed.) .253 Cornus n u t t a l l i i (seed.) -.274 T. heterophylla (tree) .225 Pseudotsuga menziesii (seed.) -.270 Blechnum spicant .112 A. macrophyllum (seed.) -.255 Polystichum munitum .089 C. n u t t a l l i i (sap.) -.236 Vaccinium parvifolium .075 Thuja p l i c a t a (sap.) -.187 Scapania bolanderi .072 P. menziesii (sap.) -.179 Rhytidiopsis robusta . 071 Rhytidiadelphus triquetrus -.174 Abies amabilis (sap.) .059 C. n u t t a l l i i (tree) - .172 Plagiothecium undulatum .054 Linnaea b o r e a l i s -.153 Axis 2 (% variance - 9.6) Polystichum munitum .379 Gaultheria shallon — .489 C. n u t t a l l i i (seed.) .188 Hylocomium splendens -.355 C. n u t t a l l i i (sap.) .184 P. menziesii (seed.) -.174 T. p l i c a t a (seed.) .178 Pinus monticola (seed.) -.117 A. macrophyllum (sap.) .176 Rhytidiopsis robusta -.114 Blechnum spicant .160 Vaccinium alaskaense -.110 A. macrophyllum (seed.) .156 Rhytidiadelphus loreus -.092 Taxus b r e v i f o l i a (sap.) .134 Vaccinium ovatum -.090 Rubus ursinus .120 Linnaea b o r e a l i s -.090 Isothecium stoloniferum .111 Chimaphila umbellata -.084 198 Table 8 : Product moment co r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the Pseudotsuga group (n = 59; ** = p < .01; * = .01 < p « .05). axis 1 axis 2 axis 2 .283* elevation .197 -.372** slope .185 .268** p o s i t i o n .238 .640** s o i l depth .371** .227 LFH pH (H 20) -.483** -.070 LFH pH (CaCl 2) -.534** -.099 LFH thickness .336** -.059 B X % N .186 .364** Bi C/N -.104 -.434** e f f . r. d . / s o i l depth -.277* -.238 distance from coast -.431** -.373** tree spp. richness -.463** -.117. shrub spp. richness -.423** .034 herb spp. richness -.432** .071 vascular spp. richness -.512** .045 understory coverage -.454** -.527** shrub coverage -.289* -.726** herb coverage -.136 .390** bryo. coverage -.408** -.528** tree basal area .069 .622** tree height .049 .588** 199 Table 9 : Species with the ten l a r g e s t p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the Thuja group. Axis 1 (% variance = 23.4) Abies amabilis (sap.) .309 Vaccinum- ovatum -.401 A. amabilis (tree) .'288 Thuja p l i c a t a (sap.) -.350 Tsuga heterophylla (seed.) .283 T. p l i c a t a (seed.) -.288 Polystichum munitum .146 Carex obnupta -.191 T. heterophylla (sap.) .130 Pinus contorta (tree) -.183 A. amabilis (seed.) .127 Linnaea b o r e a l i s -.179 Scapania bolanderi .088 Gaultheria shallon -.155 Vaccinium alaskaense .078 Pyrus fusca -.136 Blechnum spicant .073 Sphagnum girgensohnii -.119 T. heterophylla (tree) .068 Hylocomium splendens -.118 Axis 2 (%variance = 13.5) Linnaea b o r e a l i s .402 Vaccinium ovatum -.252 Carex obnupta .378 Pseudotsuga menziesii (tree) -.175 A. amabilis (sap.) .351 T. heterophylla (sap.) -.146 Coptis a s p l e n i f o l i a .295 Gaultheria shallon -.125 Calamagrostis nutkaensis .255 T. p l i c a t a (sap.) -.118 Maianthemum dilatatum .204 T. heterophylla (tree) -.109 Lysichitum americanum .169 P. menziesii (seed.) -.092 Rubus s p e c t a b i l i s .161 Polystichum munitum -.085 Vaccinium o v a l i f o l i u m .141 Taxus b r e v i f o l i a (sap.) -.080 Cornus canadensis .130 Isothecium stoloniferum -.072 200 Table 10 : Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the Thuja group (n = 40; ** = p < .01; * = .01 < p < .05). axis 1 axis 2 axis 2 .210 elevation .453** .393* drainage -.013 .385* s o i l depth .428** .283 LFH pH (H2O) .050 .361* LFH % N .550** .195 LFH C/N -.473** -.189 Bi % C .449** .078 Bi % N .516** -.061 Bi C/N .220 .448** root r e s t r i c t i n g depth .356* .383* tree spp. richness -.581** .180 shrub spp. richness -.448** .133 herb spp. richness .018 .640** vascular spp. richness -.187 .568** understory coverage -.803** .091 shrub coverage -.808** -.246 herb coverage -.159 .483** bryo. coverage -.512** .011 tree height .647** -.083 201 Table 11 : Species with the ten largest p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and three of the r e c i p r o c a l averaging ordination of the Abies group. Axis 1 (% variance = 16.7) Tsuga heterophylla (sap.) .339 Abies amabilis (sap.) -.356 T. heterophylla (seed.) .257 Rubus pedatus -.347 Pseudotsuga menziesii (tree) .222 A. amabilis (seed.) -.344 Polystichum munitum .213 A. amabilis (tree) -.285 T. heterophylla (tree) .186 Streptopus streptopoides -.188 Gaultheria shallon .131 Vaccinium alaskaense -.180 Thuja p l i c a t a (tree) .112 Rhytididelphus loreus -.155 Vaccinium parvifolium .110 Streptopus roseus -.134 Blechnum spicant .099 Athyrium f i l i x - f e m i n a -.102 S t o k e s i e l l a oregana .087 T i a r e l l a t r i f o l i a t a -.095 Axis 3 (% variance = 10.3) Gaultheria shallon .359 Sphagnum girgensohnii -.258 A. amabilis (seed.) .257 A. amabilis (tree) -.242 Rhytidiopsis robusta .237 Achlys t r i p h y l l a -.231 A. amabilis (sap.) .218 Polystichum munitum -.219 P. menziesii (tree) .206 T i a r e l l a t r i f o l i a t a -.213 T. heterophylla (tree) .164 Blechnum spicant -.200 Vaccinium alaskaense .162 T. heterophylla (sap.) -.178 Taxus b r e v i f o l i a (sap.) .139 Rubus pedatus -.152 Chamaecyparis nootkatensis (tree) .118 T. heterophylla (seed.) -.149 Vaccinium parvifolium .104 Dryopteris austriaca -.133 202 Table 12 : Product moment c o r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the Abies group (n = 40; ** = p < .01; * = .01 < p < .05). axis 1 axis 3 axis 3 -.499** -elevation -.421** .595** p o s i t i o n .071 -.500** LFH % C -.436** .314** LFH C/N -.169 .470** Bi pH (H 20) .349* -.166 B1 pH (CaCl 2) .364* -.180 Bx C/N -.065 .369* f i r e disturbance .098 .411** distance from coast -.488** .345* tree spp. richness -.197 .509** herb spp. richness -.330* .024 bryo. spp. richness -.073 -.312* vascular spp. richness -.331* .117 Herb coverage -.067 -.360* tree height .210 -.409** 203 Table 13 : Species with the ten l a r g e s t p o s i t i v e and negative eigenvector c o e f f i c i e n t s on axes one and two of the r e c i p r o c a l averaging ordination of the 105 modal p l o t s . Axis 1 (% variance = 15.0) Pseudotsuga menziesii (tree) .353 Blechnum spicant - .292 P. menziesii (seed.) .263 Abies amabilis (sap.) - .283 Acer macrophyllum (sap.) .263 A. amabilis (tree) - .206 Cornus n u t t a l l i i (sap.) .214 Thuja p l i c a t a (tree) - .168 C. n u t t a l l i i (seed.) .201 A. amabilis (seed.) - .140 A. macrophyllum (seed.) .195 Vaccinium alaskaense - .094 Hylocomium splendens .193 Gaultheria shallon - .093 Linnaea b o r e a l i s .174 Rhizomnium glabrescens - .081 Berberis nervosa .161 Tsuga heterophylla (tree) - .070 Achlys t r i p h y l l a .143 Plagiothecium undulatum — .067 Axis 2 (% variance =8.8) Tsuga heterophylla (sap.) .333 Gaultheria shallon - .299 T. heterophylla (seed.) .280 T. p l i c a t a (tree) - .257 T. heterophylla (tree) .235 Blechnum spicant - .235 Polystichum munitum .213 A. macrophyllum (sap.) - .227 P. menziesii (tree) .128 T. p l i c a t a (seed.) - .224 Picea s i t c h e n s i s (tree) .128 A. amabilis (sap.) - .223 Rhytidiopsis robusta .086 T. p l i c a t a (sap.) - .189 Hypnum c i r c i n a l e .080 C. n u t t a l l i i (seed.) - .159 Isothecium stoloniferum .071 A. macrophyllum (seed.) - .136 Polypodium g l y c y r r h i z a .058 C. n u t t a l l i i (sap.) - .113 204 Table 14 : Product moment co r r e l a t i o n s between environmental v a r i a b l e s , community c h a r a c t e r i s t i c s , and r e c i p r o c a l averaging axes of the 105 modal plots (n = 105; ** = p < .01; * = .01 < p < .05). axis 1 axis 2 axis 2 .670** elevation .222* .296* slope .150 .459** drainage -.621** -.699** material -.378** -.452** LFH thickness -.528** -.493** LFH % N -.296** -.196* LFH C/N .294** .179 B % coarse fragments .372** .294** B % C -.359** -.208* B % N -.419** -.134 e f f e c t i v e rooting depth .393** .267** root r e s t r i c t i n g depth .201* .267** e f f . r. d . / s o i l depth .586** .280** LFH t h i c k . / e f f . r. d. -.608** -.468** f i r e disturbance .717** .543** wind disturbance -.711** -.652** distance from coast .805** .621** tree spp. richness .318** -.101 shrub spp. richness -.030 -.284** herb spp. richness .559** .324** bryo. spp. richness -.266** -.207** vascular spp. richness .488** .171 understory coverage -.170** -.638** shrub coverage -.254** -.584** herb coverage -.416** -.415** bryo. coverage -.463** -.176 tree basal area -.390** -.265* tree height .291** .492** 205 Table 15 : Names of community types and vegetation groups. Vegetation groups (code) Community types (code) Pinus contorta (D) Dry Pinus-Pseudotsuga forests (Dl) Coastal dry Pinus forests (D2) Floodplain (F) Floodplain forests (Fl) Floodplain forests (Lysichitum variant) (F2) Pseudotsuga (P) Dry Pseudotsuga forests (PI) Pseudotsuga-Thuja-Acer forests (P2) Pseudotsuga-Linnaea forests (P3) Pseudotsuga-Berberis forests (P4) Tsuga-Pseudotsuga-Polystichum f o r e s t s (P5) Montane Tsuga forests (P6) Montane Tsuga-Gaultheria forests (P7) Thuja (T) Coastal dry Thuja forests (TI) Coastal Tsuga-Blechnum-Polystichum forests (T2) Coastal montane Thuja forests (T3) Coastal Thuja forests (T4) Coastal wet Thuja forests (T5) Abies (A) Montane Tsuga-Abies-Gaultheria forests (Al) Montane Abies-Tsuga forests (A2) Montane Tsuga-Abies forests (A3) Montane Abies-Streptopus forests (A4) Lowland Abies forests (A5) Tsuga-Gaultheria-Blechnum forests (A6) Tsuga-Blechnum-Polystichum forests (A7) Subalpine (SA) (no community types d i f f e r e n t i a t e d ) 206 Table 16 : Canonical analysis r e s u l t s of vegetation groups based on environmental data. Mahalanobis squared distances between groups : Subalpine Floodplain 41.1 — Pinus contorta 67.7 106.9 -Pseudotsuga 16.5 36.6 51.2 -Thuja 23.5 33.9 66.0 16.1 -Abies 12.5 38.2 54.5 9.6 5.7 SA F D P T A Table 17 : Canonical analysis r e s u l t s of Pseudotsuga group community types based on environmental data (community type codes are l i s t e d i n table 15). Mahalanobis squared distances between types : PI -P2 15.9 -P3 23.5 25.6 -P4 19.4 20.7 26.1 -P5 69.4 70.7 62.5 30.1 -P6 32.9 39.9 32.8 11.7 19.1 -P7 34.2 36.6 38.4 16.5 49.7 18,4 PI P2 P3 P4 P5 P6 P7 207 Table 18 : Canonical analysis r e s u l t s of Thuja group community types based on environmental data (community type codes are l i s t e d i n table 15). Mahalanobis squared distances between types : T2 T3 262.8 T4 140.3 82.0 T5 206.1 196.1 53.1 T2 T3 T4 T5 Table 19 : Canonical analysis r e s u l t s of Abies group community types based on environmental data (community type codes are l i s t e d i n table 15). Mahalanobis squared distances between types : A l -A2 1.8 -A3 5.3 6.2 -A4 20.9 20.2 36.8 -A5 7.0 14.7 11.6 26.0 -A6 5.5 11.5 9.6 31.7 2.1 -A7 7.8 13.6 4.2 44.5 5.4 3.5 A l A2 A3 A4 A5 A6 A7 208 Table 20 : Canonical analysis r e s u l t s of a l l community types based on environmental data (community type codes are l i s t e d i n table 15, coastal dry Thuja forests (Tl) are not included i n t h i s analysis) . Mahalanobis squared distances between types : SA -F l 73.2 -F2 89.3 38.3 -DI 82.0 139.7 156.0 -D2 124.3 154.9 185.8 54.4 -PI 51.8 77.0 82.5 58.9 81.0 P2 58.4 56.7 70.5 57.5 69.5 P3 43.1 57.3 68.8 72.9 103.8 P4 33.8 52.3 73.3 55.3 81.5 P5 36.4 61.6 85.0 85.1 108.5 P6 19.7 59.3 82.2 65.7 92.2 P7 18.4 64.4 82.7 51.6 79.0 T2 44.7 68.7 75.7 82.2 88.0 T3 34.4 69.4 59.2 103.6 124.2 T4 45.3 52.8 50.4 94.0 111.1 T5 52.8 45.3 38.9 114.7 132.2 A l 25.6 82.8 94.2 55.5 93.0 A2 34.1 110.1 96.5 108.9 139.6 A3 46.5 107.5 118.6 92.1 106.5 A4 27.4 109.5 113.1 115.8 121.1 A5 33.8 50.2 68.2 85.8 103.8 A6 49.3 78.0 85.5 104.8 108.2 A7 41.7 69.1 85.9 87.3 107.7 SA F l F2 DI D2 15.2 -9.9 16.4 -12.4 12.6 17.3 -30.6 28.7 36.0 12.7 -19.4 23.6 23.1 7.9 11.5 27.9 29.0 30.8 12.2 27.2 51.3 45.6 55.0 31.4 20.1 52.2 52.3 47.9 36.7 34.0 46.1 40.4 43.5 29.0 31.3 50.4 44.4 45.9 38.3 47.0 27.2 33.2 34.1 21.1 28.6 61.6 65.3 60.0 49.5 41.5 70.5 72.6 78.8 44.0 36.2 82.8 83.0 80.1 58.2 50.7 44.5 43.9 47.0 22.8 17.6 50.9 53.3 61.8 35.4 25.6 40.7 44.3 47.7 21.7 15.5 PI P2 P3 P4 P5 P7 9.3 -T2 33.1 35.2 -T3 35.3 33.5 22.1 -T4 36.6 33.5 16.5 11.2 T5 44.9 45.9 46.9 28.6 A l 12.5 18.4 42.4 50.3 A2 38.8 48.1 35.3 26.0 A3 41.9 39.8 28.9 24.8 A4 46.9 37.8 36.0 23.1 A5 25.4 29.1 16.4 19.7 A6 35.8 42.3 21.7 22.9 A7 23.8 33.9 15.4 26.4 P6 P7 T2 T3 14.6 -44.1 53.1 -35.1 57.7 35.8 -37.7 63.6 61.4 47.0 -36.5 52.5 58.1 35.9 25.3 14.1 27.6 35.6 40.1 29.3 21.3 36.5 46.5 40.6 30.4 21.5 42.8 32.4 29.5 29.9 T4 T5 A l A2 A3 A5 34.9 -A6 33.0 11.9 -A7 43.7 11.7 18.7 -A4 A5 A6 A7 209 Table 21 : Correlations between canonical va r i a t e s and environmental v a r i a b l e s (see Figs. 13 and 14). Environmental variables Vegetation groups CV1 CV2 A l l types CV1 CV2 Pseudotsuga CV1 CV2 Thuja CV1 CV2 Abies CV1 CV2 Elevation .32 -.02 .28 -.56 .12 .60 -.25 -.76 .74 .63 Aspect .41 -.00 .41 -.14 .15 .09 -.01 -.17 Slope .43 -.13 .34 -.51 .30 -.07 .06 -.73 .05 .91 P o s i t i o n -.63 .34 -.56 .52 .58 -.47 -.12 .48 Drainage -.83 -.10 -.82 .21 .03 .05 -.35 .41 E f f . root, depth .15 .43 .19 .19 .03 -.03 -.08 -.19 Root re s t , depth .05 .36 .02 .02 .41 .14 -.12 -.31 S o i l depth -.30 .11 -.37 -.08 .48 .12 -.06 -.19 Material -.71 .25 -.59 .52 -.05 .06 -.25 .35 LFH thickness -.36 -.47 -.53 -.32 .38 .23 -.02 .28 .40 -.18 Bj % coarse fr a g . .52 -.18 .43 -.31 -.01 -.14 .01 -.21 Texture -.26 -.08 -.26 .03 -.06 .10 -.01 .04 -.03 .19 E f f . r. d./r r e s t . d. .18 .19 .29 .27 -.42 -.22 .04 .15 E f f . r. d . / s o i l d. .51 .28 .60 .21 -.46 -.20 .05 -.03 LFH t h i c k . / e f f . r. d. -.34 -.58 -.50 -.38 .24 .23 -.19 .26 LFH pH (H 20) -.10 .42 .10 .67 -.38 -.52 -.28 -.01 LFH pH (CaCl 2) -.07 .49 .16 .70 -.44 -.51 -.22 .07 LFH % C .23 -.21 .12 -.38 .16 .20 .33 -.10 LFH % N -.25 -.38 -.44 -.35 .39 -.36 -.03 -.26 LFH C/N .41 .22 .54 .11 -.25 -.46 .23 .12 B x pH (H 20) .06 .34 .17 .46 -.04 -.54 -.02 .31 B x pH (CaCl 2) .05 .24 .13 .34 .02 -.55 -.02 .21 Bj % C -.08 -.34 -.09 -.17 -.01 -.45 .24 -.42 B x % N -.22 -.28 -.27 -.09 .42 -.43 .39 -.42 Bj % C/N .25 -.01 .34 -.08 -.30 -.00 -.27 -.11 F i r e disturbance .53 .39 .65 .14 -.07 -.38 -.01 .42 Wind disturbance -.58 -.39 -.62 -.05 -.08 .34 -.18 -.09 Vegetation groups : n = 157, r at .01 = .21; Pseudotsuga : n = 56, r at .01 = .34; Thuja : n = 36, r at .01 = .34; Abies : n = 32, r at .01 = .45 A l l types : n = 149, r at .01 = .21; Table 22 : Pseudotsuga group and community type Dl tree s t r a t a summary table (see table 15 for community type codes) . Community types Dl PI P2 P3 P4 P5 P6 P7 Dl PI P2 P3 P4 P5 P6 P7 Number of: plots 3 4 4 5 11 17 12 7 Trees (> 10 cm DBH) Mean r e l a t i v e importance value (%) Constancy (%) Acer macrophyllum 6 + + + 100 20 9 5 Arbutus menziesii 13 4 100 50 Cornus n u t t a l l i i 6 1 1 100 20 27 Pinus contorta 66 1 100 25 Pseudotsuga menziesii 20 93 67 69 50 42 33 30 100 100 100 100 100 100 100 100 Thuja p l i c a t a 1 1 12 9 12 11 12 14 33 25 50 60 72 65 75 71 Tsuga heterophylla 1 8 17 34 44 54 55 25 75 100 100 100 100 100 Saplings (0-10 cm DBH) Mean r e l a t i v e density (%) Acer macrophyllum 29 3 + 100 20 9 Arbutus menziesii 25 13 66 25 Cornus n u t t a l l i i 5 17 1 15 50 75 20 36 Pinus contorta 53 31 100 25 Pseudotsuga menziesii 22 35 10 5 + 100 75 75 20 5 Thuja p l i c a t a 1 24 12 13 1 10 12 25 100 40 27 17 33 71 Tsuga heterophylla 13 17 68 66 94 82 73 25 100 100 90 100 100 100 Seedlings (below BH) Mean r e l a t i v e density (%) Abies amabilis 5 1 1 4 + 20 18 17 58 14 Acer macrophyllum 4 2 18 + 2 + 100 50 100 36 11 8 Arbutus menziesii 18 26 33 50 Cornus n u t t a l l i i 2 20 1 2 + + 50 100 20 45 5 16 Pinus contorta 9 100 Pseudotsuga menziesii 67 64 26 41 10 1 3 7 100 100 100 100 100 52 75 71 Thuja p l i c a t a 2 15 3 8 12 6 7 50 75 40 72 52 75 85 Tsuga heterophylla 2 3 19 48 77 83 85 83 33 25 100 100 100 100 100 100 Table 22 (continued) Community types DI PI P2 P3 P4 P5 P6 P7 Species richness 1 (.05 ha) 4.3 4.2 5.7 4.2 4.4 3.7 3.9 3.8 (0.6) 2 (2.2) (0.9) (0.8) (1.1) (0.9) (0.9) (1.4) T o t a l species 1 6 8 8 10 9 8 9 7 Species d i v e r s i t y 3 : Exp (H') 5 2.5 1.4 2.9 2.7 3.1 3.0 2.7 2.8 1/X6 2.0 1.1 2.1 1.9 2.6 2.6 2.4 2.4 Mean basal area (m 2/ha) 1 + 30. 7 86.2 132.5 89.4 138.4 158.4 114.5 86.0 (6.5) (24.5) (20.5) (20.3) (43.5) (52.9) (31.1) (13.4) Mean density(trees/ha) 3 700 300 340 420 485 414 388 634 (87) (73) (157) (136) (104) (118) (122) (288) Mean max. height (m) 18 44 64 48 58 61 50 41 (7) (7) (8) X10) (10) (8) (8) (16) 1 Includes tree, sapling and seedling s t r a t a 2 (standard deviation) 3 Includes tree stratum only 4 Includes trees and saplings 5 A n t i l o g of Shannon's Index 6 Reciprocal of Simpson's Index Table 23 : Pseudotsuga group and community type DI understory s t r a t a summary table (see table 15 for community type codes). Community types DI PI P2 P3 P4 P5 P6 P7 DI PI P2 P3 P4 P5 P6 P7 Number of pl o t s 3 4 4 5 11 17 12 7 Shrubs Mean coverag e (%) Constancy (%) Amelanchier a l n i f o l i a + + + + + + + 66 50 25 40 18 5 16 Arctostaphylos columbiana 7 + 100 25 Berberis nervosa 5 12 13 10 11 3 6 4 100 100 100 100 100 58 58 57 Gaultheria shallon 13 60 13 44 10 + 4 75 100 100 75 100 90 35 66 100 Holodiscus di s c o l o r + 3 + 2 + 33 50 25 40 9 Rosa gymnocarpa + 1 2 3 + + + 1 100 75 100 80 54 11 16 14 Rubus ursinus 1 2 8 1 1 + + 1 100 75 100 60 72 35 16 28 Symphoricarpos spp. + + 1 + 50 50 40 18 Vaccinium alaskaense 2 + 3 1 5 8 25 20 36 65 50 14 Vaccinium ovatum 18 11 + 1 + + 4 66 50 25 20 18 11 14 Vaccinium parvifolium + 7 2 10 12 7 20 7 100 100 100 100 100 100 100 Herbs A c h i l l e a m i l l e f o l i u m + 66 Achlys t r i p h y l l a + 2 11 12 4 3 4 + 33 100 100 100 100 100 75 42 Adenocaulon b i c o l o r + + + + 50 20 18 17 A l l o t r o p a v i r g a t a + + + + + 50 40 27 16 14 Apocynum androsaemifolium + + + 66 50 8 Arenaria macrophylla + + + + 33 50 20 9 Blechnum spicant + 3 2 + 9 52 58 28 Boschniakia hookeri + + + + 100 60 9 42 Bromus vulga r i s + + + 50 20 5 Calypso bulbosa + + + 50 40 27 Campanula sc o u l e r i + + + + + 75 50 40 9 16 Chimaphila menziesii + + + + + + 50 75 80 63 17 50 Table 23 (continued) Community types Dl PI P2 P3 P4 P5 P6 P7 Dl PI P2 P3 P4 P5 P6 P7 Herbs (continued) Chimaphila umbellata + 6 + 2 + + + + 33 100 50 100 54 5 41 42 C o r a l l o r h i z a maculata + + + + 25 60 8 14 Co r a l l o r h i z a mertensiana + + + + + 60 27 11 50 28 Cryptogramma crispa + 66 Danthonia spicata 4 1 100 50 Festuca occid e n t a l i s + 3 2 1 + + + 66 100 50 40 9 8 14 Festuca ovina 1 66 Festuca s u b u l i f l o r a + 3 2 + + + 1 50 100 100 36 35 16 28 Fragaria v i r g i n i a n a + + 66 50 Galium t r i f l o r u m + + 50 29 Goodyera o b l o n g i f o l i a + + + + + + + + 100 100 100 100 81 35 33 42 Hieracium albiflorum + 1 + + + + 100 75 25 20 16 14 Hypochaeris radicata + + 66 50 Lathyrus nevadensis + 1 25 60 Linnaea bo r e a l i s 1 8 10 20 8 2 1 3 33 100 100 100 81 29 33 28 L i s t e r a cordata + + + + + + + + 66 75 75 80 54 17 50 85 Madia madioides 1 50 Montia p a r v i f l o r a + + + 50 9 17 Polypodium gly c y r r h i z a + + 1 + + + + + 66 100 100 40 36 35 25 14 Polystichum munitum + + 18 4 8 29 3 + 66 100 100 100 100 100 75 57 Pteridium aquilinum 6 + + + + + + 100 75 60 63 23 8 14 Saxifraga ferruginea + 66' Se l a g i n e l l a wallacei 5 + + + 100 25 20 5 T i a r e l l a l a c i n i a t a + + + + + 25 20 54 41 41 T i a r e l l a t r i f o l i a t a 1 + 1 2 1 50 20 63 88 33 T r i e n t a l i s l a t i f o l i a + 2 4 •2 + + + + 66 100 100 80 81 17 33 28 T r i l l i u m ovatum + + + + 25 54 76 58 V i o l a sempervirens + + 1 2 2 + + 33 75 75 80 54 17 25 Table 23 (continued) Community types DI PI P2 P3 P4 P5 P6 P7 DI PI P2 P3 P4 P5 P6 P7 Bryophytes & lichens Cladina impexa 1 66 Cladina rangiferina 5 + + 100 50 14 Cladonia b e l l i d i f l o r a 1 + + 100 25 14 Cladonia multiformis 3 + 100 50 Cladonia g r a c i l i s 1 + 66 25 Dicranum fuscescens + 2 1 1 + + 1 2 33 100 100 100 90 58 58 100 Dicranum scoparium 10 2 + + 66 50 25 20 Heterocladium macounii 1 1 + 27 52 33 Hylocomium splendens 2 21 22 52 23 2 14 35 100 100 100 100 100 76 91 100 Hypnum c i r c i n a l e + + + 1 3 3 1 50 50 40 81 94 100 85 Isopterygium elegans + + + + + 33 20 27 76 58 Isothecium stoloniferum 2 3 3 + 2 5 4 + 33 75 75 20 81 94 83 42 Leucolepis menziesii 3 + + + + 75 60 18 11 8 P e l t i g e r a leucophlebia 1 + + 66 75 28 P e l t i g e r a membranacea + 1 + + + + 33 75 18 5 16 14 P e l t i g e r a polydactyla + + + + 18 17 50 14 Plagiothecium undulatum + + + 1 + .•2 2 + 33 25 50 60 45 70 50 57 Pogonatum contortum 1 3 + + + + 50 100 9 29 50 28 Polytrichum commune 1 + 100 25 Polytrichum juniperinum 4 2 + 100 100 20 Rhacomitrium canescens 3 2 100 75 Rhizomnium glabrescens + + + + + + 25 20 54 65 41 14 Rhytidiadelphus loreus + + 2 4 6 4 4 15 66 100 75 100 90 76 83 85 Rhytidiadelphus triquetrus 1 + 6 1 + + 1 66 75 75 80 18 5 28 Rhytidiopsis robusta + 1 2 + 9 5 33 40 63 17 66 71 Scapania americana + 66 Scapania bolanderi + 1 1 2 4 2 50 100 81 94 100 85 Stereocaulon tomentosum 1 66 S t o k e s i e l l a oregana 4 28 24 6 20 13 10 10 100 100 100 100 100 94 91 71 Trachybryum megaptilum 1 1 1 + + 1 1 33 100 40 45 5 50 71 Rock 28 2 9 1 2 10 8 2 100 50 50 20 54 88 75 28 Table 23 (continued) Community types Dl PI P2 P3 P4 P5 P6 P7 Strata mean coverage (%) Shrubs 45 98 38 72 39 12 36 102 (7)1 (35) (12) (46) (24) (11) (32) (12) Herbs 24 35 54 49 26 44 13 7 (26) (10) (28) (28) (25) (29) (15) (8) Bryo. & lichens 54 64 64 73 59 35 55 73 (5) (14) (9) (31) (25) (19) (24) (38) Tot a l understory 123 197 157 195 125 91 105 182 Species richness (.05 ha) (22) (24) (36) (54) (48) (37) (46) (51) Shrubs 8.7 7.8 6.8 6.4 5.7 4.5 3.8 3.6 (1.5) (0.3) (1.5) (1.5) (2.4) (2.5) (1.4) (1.3) Herbs 17.3. 20.3 18.5 17.4 14.3 11.7 10.4 6.9 (7) (0.9) (4.4) (6.2) (2.8) (6.2) (5.5) (5.7) Bryo. & lichens 18.7 13.8 9.5 11.0 10.8 11.0 12.0 9.9 (3.2) (3.4) (3.3) (2.0) (2.4) (2.5) (2.3) (2.3) Tot a l species : Shrubs 12 14 12 12 15 17 12 9 Herbs 32 33 36 35 41 54 42 25 Bryo. & lichens 31 23 17 20 26 27 29 21 Species d i v e r s i t y Shrubs & herbs E x p ( H ' ) 2 9.6 15.5 15.2 15.0 14.7 8.7 8.9 5.7 I A 3 18.1 8.7 13.8 9.1 11.5 6.0 8.8 2.9 Bryo. & lichens Exp {H') 2 20.6 9.0 6.6 7.1 8.4 10.7 12.8 8.3 1/A3 .. 16.2 5.4 4.5 3.9 5.6 7.5 10.0 6.3 (standard deviation) Antilog of Shannon's Index 3 Reciprocal of Simpson's Index Table 24 : Thuja group and community types D2, F l and F2 tree s t r a t a summary table (see table 15 for community type codes). Community types D2 T l T2 T3 T4 T5 F2 F l D2 T l T2 T3 T4 T5 F2 F l Number of plots 4 3 6 7 19 4 2 8 Trees (> 10 cm DBH) Mean r e l a t i v e importance value (%) Constancy i Abies amabilis 1 28 18 12 4 9 33 100 100 89 50 12 Chamaecyparis nootkatensis 15 4 5 100 33 28 Picea sitchensis 1 5 + 37 35 33 16 5 100 62 Pinus contorta 28 11 100 75 Pinus monticola 4 + 1 75 5 25 Pseudotsuga menziesii 17 11 3 5 100 66 16 12 Taxus b r e v i f o l i a 3 1 + 6 ' 1 100 42 15 100 50 Thuja p l i c a t a 17 47 18 51 54 53 37 21 75 100 50 100 100 100 100 62 Tsuga heterophylla 19 34 46 25 33 29 21 26 100 100 100 100 100 100 100 87 Saplings (0-10 cm DBH) Mean r e l a t i v e density (%) Abies amabilis 4 64 13 + 14 1 83 100 57 25 50 25 Chamaecyparis nootkatensis 35 + 100 14 Pinus contorta 14 1 100 50 Pinus monticola 1 1 75 25 Taxus b r e v i f o l i a 1 4 8 6 25 33 57 75 Thuja p l i c a t a 27 54 6 7 49 2 100 100 57 63 100 12 Tsuga heterophylla 21 42 96 30 72 42 86 85 100 100 100 85 100 100 100 87 Seedlings (below BH) Mean r e l a t i v e density (%) Abies amabilis 5 11 5 3 83 100 ?74 25 Chamaecyparis nootkatensis 24 2 100 14 Picea sitchensis + 15 23 15 100 62 Pinus contorta 12 100 Pinus monticola 1 1 75 25 Pseudotsuga menziesii 4 5 1 100 66 12 Thuja p l i c a t a 29 50 6 24 27 70 30 10 100 100 50 100 94 100 100 25 Tsuga heterophylla 28 41 89 63 67 29 55 49 100 100 100 100 100 100 100 100 Table 24 (continued) Community types D2 TI T2 T3 T4 T5 F2 F l Species richness Total s p e c i e s 1 Species d i v e r s i t y 3 : Exp (H') 1/A6" Mean basal area (m 2/ha)^ Mean density (trees/ha) Mean max. height (m) 6.5 (1.0) 2 4.7 (0.5) 3.0 (0.6) 3.8 (0.7) 8 7 5 5 5.4 5.1 3.6 2.8 3.6 3.1 3.3 2.8 30.2 (10.2) 86.0 (9.5) 142.3 (47.4) 187.3 (81.5) 695 (213) 740 (250) 407 (93) 583 (195) 17 (10) 30 (4) 52 42 (9) 3.8 4.2 4.0 3.9 (0.7) (0.5) (-) (1.8) 6 6 5 8 2.7 3.2 3.4 4.8 2.4 2.6 3.1 4.1 180.4 87.7 236.5 246.2 (54.8) (21.6) (14.8) (124.9) 455 855 330 315 (148) (209) (19) (124) 43 24 56 60 (6) (1) (-) (9) Includes tree, sapling and seedling s t r a t a (standard deviation) Includes tree stratum only Includes trees and saplings Antil o g of Shannon's Index Reciprocal of Simpson's Index Table 25 : Thuja group and community types D2, F l et F2 understory s t r a t a summary table (see table 15 for community type codes). Community types D2 TI T2 T3 T4 T5 F2 F l D2 TI T2 T3 T4 T5 F2 F l Number of plots 4 3 6 7 19 4 2 8 Shrubs Mean coveraj ?e- (%) Constancy (%) Gaultheria shallon 45 64 9 45 57 75 33 1 100 100 83 100 100 100 100 37 Menziesia ferruginea 1 2 + 4 2 5 5 + 50 100 33 85 94 100 100 12 Pyrus fusca + + 8 + 25 5 100 12 Ribes bracteosum 5 62 Rubus s p e c t a b i l i s + + + 2 2 21 23 33 83 57 78 75 100 100 Vaccinium alaskaense 2 + 5 15 11 6 7 1 50 66 83 100 100 100 100 75 Vaccinium ova l i f o l i u m + + 2 1 + 4 1 25 66 71 57 25 100 37 Vaccinium ovatum 25 50 + 1 34 2 75 100 16 57 100 100 Vaccinium parvifolium 6 7 13 14 13 13 13 5 100 100 100 100 100 100 100 100 Herbs Achlys t r i p h y l l a + 5 5 50 Adenocaulon b i c o l o r 1 + 50 50 Adiantum pedatum + 50 Agrostis scabra + 75 Aruncus Sylvester + 62 Athyrium f i l i x - f e m i n a + + 1 13 33 10 100 100 Blechnum spicant + 32 46 48 61 65 29 6 26 100 100 100 100 100 100 62 Boschniakia hookeri + + + + 75 66 5 50 Boykinia elata + + + 28 100 25 Bromus vulga r i s + 50 Calamagrostis nutkaensis 1 50 Carex obnupta + 5 3 + 10 75 100 12 Coptis a s p l e n i f o l i a 3 + + 57 5 12 Table 25 (continued) Community types D2 T l T2 T3 T4 T5 F2 F l D2 T l T2 T3 T4 T5 F2 F l Herbs (continued) Danthonia spicata + 75 Dryopteris austriaca + + 50 50 Galium t r i f l o r u m + + 1 5 50 87 Goodyera o b l o n g i f o l i a + + + + 75 28 15 12 Linnaea borealis 4 1 1 + 5 100 66 42 10 100 L i s t e r a caurina + + + 33 71 5 L i s t e r a cordata + + + + + 33 16 85 47 25 Luzula p a r v i f l o r a + + 16 75 Lysichitum americanum 2 + 26 + 10 25 100 12 Maianthemum dilatatum + + 2 + 2 1 3 50 33 71 57 100 100 100 Melica subulata 1 62 Polystichum munitum 12 1 + 23 45 100 42 26 100 100 Rubus pedatus 3 57 Saxifraga ferruginea + 75 Se l a g i n e l l a wallacei + 50 Streptopus amplexifolius + + + + + + 33 85 10 25 100 75 T i a r e l l a l a c i n i a t a + 1 + 2 + 66 85 21 100 62 T i a r e l l a t r i f o l i a t a + 1 + 5 9 66 85 26 100 100 Trautv e t t e r i a c a r o l i n i e n s i s 10 100 Trisetum cernuum + + 100 25 T r i l l i u m ovatum + + + 1 50 42 36 75 Veratrum v i r i d e + + + + + 28 5 50 50 37 V i o l a g l a b e l l a + + + 14 100 50 Bryophytes & lichens Andreaea rupestris + 50 Blepharostoma trichophyllum + + 1 + 33 21 50 50 Calypogeia muellerana + + + 1 33 50 26 50 Table 25 (continued) Community types D2 TI T2 T3 T4 T5 F2 F l D2 TI T2 T3 T4 T5 F2 F l Bryophytes & lichens  (continued) Campylopus atrovirens Cephalozia bicuspidata Cladina impexa Cladina r a n g i f e r i n a Cladonia b e l l i d i f l o r a Cladonia multiformis Cladonia g r a c i l i s Cladonia u n c i a l i s Dicranum fuscescens Dicranum scoparium Diplophyllum albicans Diplophyllum plicatum Hebertus aduncus Heterocladium macounii Hookeria lucens Hylocomium splendens Hypnum c i r c i n a l e Isopterygium elegans Isothecium stoloniferum Leucolepis menziesii Mylia t a y l o r i i P e l l i a neesiana P l a g i o c h i l a porelloides Plagiomnium insigne Plagiothecium undulatum Pleurozium schreberi Polytrichum commune Polytrichum juniperinum Polytrichum p i l i f e r u m + 3 9 + + 1 1 + 7 + + + + 1 + + + + 1 1 + + 14 + + 5 + 2 2 2 2 + + + + + + + + + + + + + + 1 + 1 + + + + + + 1 + + 4 7 8 2 2 1 + + + + 1 + + + 1 3 3 1 1 1 + 10 6 + + + + + • + + 3 + + + + + 3 + + 2 6 4 4 4 4 2 50 100 100 100 50 100 100 25 100 25 75 33 66 71 57 75 50 12 25 75 75 50 50 100 16 42 36 25 12 75 12 33 14 26 75 12 33 10 50 15 75 66 33 25 100 66 100 84 100 100 62 100 16 85 100 100 100 87 66 83 85 26 25 37 33 100 57 10 50 50 100 83 100 89 50 75 10 100 75 16 14 5 50 33 57 15 100 50 33 33 42 63 75 100 62 100 75 100 83 100 100 100 100 62 Table 25 (continued) Community types D2 TI T2 T3 T4 T5 F2 F l D2 TI T2 T3 T4 T5 F2 F l Bryophytes & lichens (continued) Rhacomitrium heterostichum 6 50 Rhacomitrium lanuginosum 7 75 Rhizomnium glabrescens + + 2 4 5 1 15 2 50 100 100 100 94 100 100 100 Rhytidiadelphus loreus 11 20 1 11 6 12 3 5 100 100 83 100 94 100 100 100 Scapania bolanderi 2 2 5 6 3 2 2 + 75 33 100 100 78 25 100 87 Sphagnum girgensohnii 1 2 + + 3 50 66 28 10 75 Sphagnum henryense + + + 5 25 100 Stereocaulon subcoralloides + 100 St o k e s i e l l a oregana 2 13 3 6 13 17 + 9 75 100 100 100 100 75 50 62 St o k e s i e l l a praelonga 3 17 6 25 100 50 Rock 26 1 1 1 1 100 33 66 28 12 Table 25 (continued) Community types D2 T l T2 T3 T4 T5 F2 F l Strata mean coverage_(%) Shrubs 79 125 29 80 87 143 86 46 (30) 1 (31) (28) (35) (30) (9) (25) (44) Herbs 9 34 60 66 65 88 94 119 (7) (32) (27) (19) (14) (14) (28) (34) Bryo. & lichens 62 63 27 42 47 58 62 39 (22) (26) (9) (20) (20) (21) (-) (21) Total understory 150 221 116 188 199 289 242 204 Species richness (.05 ha) (47) (45) (23) (45) (42) (15) (3) (52) Shrubs 5.3 5.0 4.7 5.3 6.1 7.3 7.0 5.9 (0.9) (1.0) (1.4) (1.1) (1.3) (0.5) (-) (1.8) Herbs 9.0 3.7 6.2 11.3 4.8 7.5 14.5 20.1 (1.8) (0.6) (3.0) (4.5) (3.1) (1.9) (3.5) (5.2) Bryo. & lichens 20.5 13.0 11.7 13.4 12.4 13.5 16.0 12.1 (1.3) (1.0) (2.0) (1.6) (1.9) (1.3) (2.8) (2.0) Total species : Shrubs 11 6 7 7 10 9 7 16 Herbs 20 7 14 24 24 13 17 49 Bryo. & lichens 32 20 22 25 36 22 20 26 Species d i v e r s i t y Shrubs & herbs : Exp (H') 2 5.3 4.6 5.5 9.6 5.4 8.8 13.3 19.7 1/A3 6.3 3.8 3.8 6.4 3.7 6.2 10.6 11.7 Bryo. & lichens : Exp (H') 2 18.7 10.1 11.6 11.5 12.7 12.8 12.1 14.5 1/A3 14.6 7.6 8.8 9.2 9.3 9.7 9.4 11.4 1 (standard deviation) 2 Antilog of Shannon ' s Index 3 'Recip r o c a l of Simpson's Ii Table 26 : Abies group tree strata summary table (see table 15 f o r community type codes) . Community types A l A2 A3 A4 A5 A6 A7 A l A2 A3 A4 A5 A6 A7 Number of plots 3 2 4 4 12 2 5 Tree (> 10 cm DBH) Mean r e l a t i v e importance value (%) Constancy (%) Abies amabilis 12 25 45 65 74 25 4 66 100 100 100 100 100 40 Chamaecyparis nootkatensis 2 66 Picea sitchensis 9 20 Pseudotsuga menziesii 25 7 17 100 50 60 Thuja p l i c a t a 8 22 3 11 13 60 100 16 50 40 Tsuga heterophylla 52 45 55 35 23 64 57 100 100 100 100 91 100 100 Saplings (0-10 cm DBH) Mean r e l a t i v e density (%) Abies amabilis 44 39 27 80 46 1 1 100 100 100 100 100 50 20 Thuja p l i c a t a 3 2 + 1 33 50 8 20 Tsuga heterophylla 48 58 73 19 54 99 98 100 100 100 50 100 100 100 Seedlings (below BH) Mean r e l a t i v e density (%) Abies amabilis 41 30 12 48 27 5 3 100 100 100 100 100 100 : 40 Thuja p l i c a t a 3 8 1 3 6 2 66 50 50 50 33 40 Tsuga heterophylla 54 62 87 49 67 95 94 66 100 100 100 100 100 100 N3 LO Table 26 (continued) Community types A l A2 A3 A4 A5 A6 A7 Species richness 1 5.0 (1.0) 2 3.0 (1.4) 2.7 (0.9) 3.5 (1.9) 2.5 (0.8) 2.5 (0.7) 2.8 (0.4) Total species 1 6 4 4 4 5 3 5 Species d i v e r s i t y 3 : Exp (H') 5 1/A6 3.4 2.8 3.4 3.1 2.0 2.0 2.0 1.9 1.9 1.7 2.4 2.1 3.4 2.6 Mean basal area (m 2/ha) i + 121.0 (44.5) 146.5. (47.4) 79.5 (11.9) 121.9 (29.6) 107.7 (20.4) 116.5 (43.1) 185.2 (37.4) Mean density (trees/ha) 3 700 (295) 280 (28) 435 (153) 420 (140) 517 (149) 420 (56) 348 (114) Mean max. height (m) 44 (12) 50 (-) 53 (6) 53 (3) 54 (6) 46 (9) 64 (4) Includes tree, sapling and seedling s t r a t a (standard deviation) Includes tree stratum only Includes trees and saplings A n t i l o g of Shannon's Index Reciprocal of Simpson's Index Table 27 : Abies group understory s t r a t a summary table (see table 15 for community type codes). Community types A l A2 A3 A4 A5 A6 A7 .'Al A2. A3 A4 A5 A6 A7 Number of plots 3 2 4 4 12 2 5 Shrubs Mean coverage (%) Constancy (%) Gaultheria shallon 34 2 + 1 43 + 100 50 50 41 100 40 Menziesia ferruginea + + + + 2 66 50 25 41 50 Oplopanax horridus 1 + 75 16 Rubus s p e c t a b i l i s + 2 + 1 + 50 100 25 91 80 Sorbus sitchensis + 66 Vaccinium alaskaense 41 43 2 31 25 6 5 100 100 100 100 100 100 100 Vaccinium ovalifolium 1 1 + 3 66 50 25 66 Vaccinium parvifolium 27 14 22 4 10 28 9 100 100 100 100 100 100 100 Herbs Achlys t r i p h y l l a + 4 + 4 3 + + 33 50 25 100 50 50 40 Adiantum pedatum 1 + + 50 16 20 Athyrium f i l i x - f e m i n a + 3 + + + 50 75 50 50 60 Blechnum spicant 1 16 11 7 17 15 25 33 100 75 100 100 100 100 C l i n t o n i a u n i f l o r a 1 + 50 16 Cornus canadensis 1 + + + 33 50 50 16 Dryopteris austriaca + 1 2 + 25 50 66 60 Gymnocarpium dryopteris 1 + 75 25 Hypopitys monotropa + + + + 33 50 25 25 L i s t e r a caurina + + + + 100 50 75 16 L i s t e r a cordata + + + + 66 50 50 20 Maianthemum dilatatum + + + 1 + + 33 50 25 50 41 20 Polystichum munitum + 4 2 2 3 + 29 33 50 100 75 83 100 100 Rubus pedatus 1 31 3 50 75 50 Streptopus amplexifolius + + + + 50 75 41 60 Table 27 (continued) Community types A l A2 A3 A4 A5 A6 A7 A l A2 A3 A4 A5 A6 A7 Herbs (continued) Streptopus roseus + + 5 + + 33 50 100 25 20 Streptopus streptopoides 8 + 100 8 T i a r e l l a l a c i n i a t a + + + + + + 50 50 75 50 50 60 T i a r e l l a t r i f o l i a t a 3 + 3 4 + + 50 25 75 91 50 80 Trau t v e t t e r i a c a r o l i n i e n s i s 1 + + 50 33 50 T r i l l i u m ovatum + 1 + + + + + 33 50 75 100 58 50 60 Bryophytes & lichens Cephalozia bicuspidata 2 1 3 1 50 25 83 80 Dicranum fuscescens 1 1 + + + + 100 100 50 100 33 20 Diplophyllum albicans 2 1 50 16 Eurhynchium pulchellum + 50 Heterocladium macounii 2 + + 25 8 80 Hookeria lucens + + + 1 + + 50 75 50 75 50 80 Hylocomium splendens 3 + 1 + 3 7 + 100 50 25 25 83 50 20 Hypnum c i r c i n a l e 2 3 2 3 + + 1 66 100 75 100 . 25 100 80 Isopterygium elegans + 2 + 1 + 1 50 100 25 66 50 40 Isothecium stoloniferum 2 1 2 1 2 2 4 66 100 75 100 83 100 100 Lepidozia reptans + + + + 3 33 50 75 8 50 P l a g i o c h i l a porelloides + + + + 50 58 100 20 Plagiothecium undulatum + 4 5 8 8 11 4 33 100 100 100 100 100 80 Rhizomnium glabrescens 1 4 1 7 6 2 50 75 75 100 100 80 Rhytidiadelphus loreus 17 6 3 11 17 1 2 100 100 50 75 100 100 80 Rhytidiopsis robusta 3 3 1 66 100 100 Scapania bolanderi 3 4 6 2 2 7 4 100 100 75 100 91 100 100 S t o k e s i e l l a oregana 5 + + + 7 24 2 66 50 25 25 75 100 100 Rock 1 3 + 5 50 25 33 60 Table 27 (continued) Community types A l A2 A3 A4 A5 A6 A7 Strata mean coverage (%) Shrubs 104 61 25 36 40 80 15 (34) 1 (33) (25) (30) (21) (29) (8) Herbs 3 31 14 70 35 16 56 (!) (42) (9) (60) (31) (20) (27) Bryo. & lichens 39 25 33 30 54 61 22 (16) (12) (18) (20) (17) (11) (7) Total understory 147 116 72 137 129 158 93 (44) (88) (18) (73) (48) (20) (22) Species richness (.05 ha) Shrubs 5.3 4.0 3.8 3.3 4.8 3.5 3.4 (1.1) (2.8) (0.5) (1.0) (1.0) (0.7) (0.9) Herbs 5.0 11.0 7.0 15.0 10.9 6.0 7.8 (2.6) (2.7) (5.4) (5.1) (7.1) (5.6) (2.5) Bryo. & lichens 7.3 10.5 11.3 11.0 12.7 11.0 11.4 (2.1) (4.9) (2.9) (2.9) (2.5) (-) (3.6) Total species : Shrubs 7 6 5 5 9 4 5 Herbs 14 20 16 25 41 10 17 Bryo. & lichens 10 14 23 19 30 14 21 Species d i v e r s i t y Shrubs & herbs : .Exp (H') 2 4.9 6.3 4.8 9.8 9.8 4.5 5.5 1/X3 3.8 3.7 3.4 8.0 6.4 3.6 4.7 Bryo. & lichens : Exp (H') 2 8.5 8.1 13.0 9.7 12.2 7.6 11.9 1/X3 7.4 6.6 10.4 7.7 8.8 6.1 9.4 1(standard deviation) 2 Antilog of Shannon' 1 s Index 3 Reciprocal of Simpsi 228 Table 28 : Subalpine vegetation group tree s t r a t a summary table. Mean r e l a t i v e Constancy importance value (%) (11 plots) (%) Trees (> 10 cm DBH) Abies amabilis 14 82 Chamaecyparis nootkatensis 7 36 Pseudotsuga menziesii 10 64 Thuja p l i c a t a 8 36 Tsuga heterophylla 51 91 Tsuga mertensiana 10 45 Saplings (0-10 cm DBH) Mean r e l . density (%) Abies amabilis 78 100 Chamaecyparis nootkatensis 3 27 Pseudotsuga menziesii + 9 Thuja p l i c a t a 3 45 Tsuga heterophylla 13 82 Tsuga mertensiana 3 45 Seedlings (below BH) Mean r e l . density (%) Abies amabilis 46 100 Chamaecyparis nootkatensis 3 45 Pseudotsuga menziesii 1 54 Thuja p l i c a t a 3 36 Tsuga heterophylla 42 91 Tsuga mertensiana 5 18 Mean basal area (m2/ha) : 113.2 (26.3) Mean density (trees/ha) : 520 (243) 229 Table 29 : C l a s s i f i c a t i o n of community type s o i l s to the subgroup l e v e l (see table 15 for community type codes). S o i l subgroups (C.S.S.C., 1978) Community ODB GDB OHFP GHFP OFHP GFHP HG GSB CR OR types EDB OTHFP DUHFP SA 1 1 7 1 1 1 DI 3 D2 1 3 F l 1 6 1 F2 2 PI 3 1 P2 1 3 P3 5 P4 2 9 P5 2 12 1 2 P6 1 10 1 P7 1 6 T l 1 2 2 T2 1 4 1 T3 1 1 1 2 2 T4 3 2 3 4 7 T5 1 3 A l 3 A2 2 A3 4 A4 . 1 1 1 1 A5 1 1 6 1 2 1 A6 2 A7 3 1 1 DB : D y s t r i c Brunisol SB : Sombric Brunisol E : Eluviated HEP:": Humo-Ferric Podzol CR : Cumulic Regosol G : Gleyed FHP : Ferro-Humic Podzol OR : Orthic Regosol OT : Or t s t e i n HG : Humic Gleysol 0 : Orthic DU : Duric 1 SA : Subalpine vegetation group 2 Typic F o l i s o l s 230 Table 30 : Mean species richness of community types (for .05 ha). Mean species richness Community types vascular t o t a l 2 DI Dry Pinus-Pseudotsuga f o r e s t s 30.3 1 (8.6) 49.0 ( ;6.0) D2 Coastal dry Pinus f o r e s t s 20. 7 (1.2) 41.2 ( :o.9) F l Floodplain f o r e s t s 29.9 (7.8) 42.0 ( :6.9) F2 Floodplain f o r e s t s (Lysichitum variant) 25.5 (3.5) 41.5 :o.7) PI Dry Pseudotsuga f o r e s t s 32.2 (3.9) 46.0 ( ;2.i) P2 Pseudotsuga-Thuja-Acer f o r e s t s 31.0 (4.2) 39. 7 [6.2) P3 Pseudotsuga-Linnaea f o r e s t s 28.0 (7.7) 39.0 :s.5) P4 Pseudotsuga-Berberis f o r e s t s 24.4 (4.9) 35.2 :6.7) P5 Tsuga-Pseudotsuga-Polystichum f o r e s t s 19.8 (7.6) 30.8 :9.D P6 Montane Tsuga fo r e s t s 18.1 (6.6) 30.1 :7.2) P7 Montane Tsuga-Gaultheria f o r e s t s 14.3 (7.6) 24.1 ( :8.2) T l Coastal dry Thuja forests 13.3 (1.5) 26.3 :2.3) T2 Coastal Tsuga-Blechnum-Polystichum forests 13.8 (3.8) 25.5 :5.D T3 Coastal montane Thuja f o r e s t s 20.4 (5.3) 33.8 :5.o) T4 Coastal Thuja f o r e s t s 14.6 (4.4) 27.0 ( :5.7) T5 Coastal wet Thuja f o r e s t s 19.0 (2.6) 32.5 :2.4) A l Montane Tsuga-Abies-Gaultheria f o r e s t s 15.3 (2.9) 22.7 ( :2.D A2 Montane Abies-Tsuga f o r e s t s 18.0 (17.0) 28.5 [21.9) A3 Montane Tsuga-Abies f o r e s t s 13.5 (5.8) 24.7 [8.3) A4 Montane Abies-Streptopus f o r e s t s 21.7 (5.4) 32.7 [7.9) A5 Lowland Abies f o r e s t s 18.2 (7.6) 30.8 [9.3) A6 Tsuga-Gaultheria-Blechnum f o r e s t s 12.0 (5.6) 23.0 [5.6) A7 Tsuga-Blechnum-Polystichum f o r e s t s 14.0 (2.5) 25.4 [9.3) (standard deviation) also includes bryophytes and lichens 231 Table 31 : Homogeneity and richness of vegetation s t r a t a within community types compared with a f i r e disturbance index (see table 15 for community type codes). Community types (plots) trees sap-l i n g s seed-l i n g s shrubs herbs bryo. & lichens a l l s t r a t a avg... f i r e 3 index DI (3) h o m ; 2 r i c h . z .87 3.3 .85 2.7 .66 3.3 8.7 .49 17.3 .22 18.7 .62 1.0 (-) P3 (5) h o m : r i c h . .92 3.8 .75 2.2 .85 3.2 .66 6.4 .50 17.4 .88 11.0 .76 1.0 (-) P4 ( i i ) h o m : r i c h . .89 3.4 .51 2.0 .93 4.1 .72 5.7 .50 14.3 .65 10.8 .70 0.9 (0.3) PS (i7) h o m ; r i c h . .81 3.0 .97 1.6 .91 2.6 .63 4.5 .92 11.7 .57 11.0 .80 0.8 (0.4) pe ( i 2 ) : h o m : r i c h . .88 3.1 .87 1.6 .98 3.5 .58 3.8 .24 10.4 .44 12.0 .66 0.9 (0.3) P7 (7) h o m ; r i c h . .79 3.0 .76 2.3 .97 3.3 .84 3.6 .20 6.9 .56 9.9 .69 0.6 (0.5) D2 (4) h o m ; r i c h . .64 5.5 .55 5.0 .67 6.3 .88 5.3 .64 9.0 .63 20.5 .67 0 (-) T2 (6) h o m : r i c h . .66 2.8 .99 1.8 .98 2.3 .76 4.7 .96 6.2 .56 11.7 .82 0 (-) T3 (7) h o m ; r i c h . .90 3.7 .87 2.6 .82 3.4 .85 5.3 .93 11.3. .55 13.4 .82 0 (-) M (19) H - H . .92 3.1 .88 2.8 .83 2.9 .86 6.1 .98 4.8 .68 12.4 .86 0.1 (0.3) » < « S i . .95 4.0 .95 3.8 .92 2.3 .95 7.3 .97 7.5 .50 13.5 .87 0.5 (0.6) FI (8) h o m : r i c h . .40 2.8 .67 1.9 .54 3.0 .48 5.9 .65 20.1 .31 12.1 .51 0.3 (0.5) AS (12) h o m : r i c h . .90 2.1 .77 2.1 .72 2.5 .83 4.8 .76 10.9 .56 12.7 .76 0.2 (0.4) A7 (5) h o m : r i c h . .75 2.6 .99 1.4 .99 2.2 .56 3.4 .95 7.8 .50 11.4 .79 0.4 (0.5) stratum avg. ( a l l types) .81 .81 .84 .74 .6.9 .54 .74 Homogeneity c o e f f i c i e n t 2 Species richness, average f or .05 ha 3 F i r e : 0 = absence, 1 = presence (S.D.) 232 Table 32 : Tree seedling abundance on undecomposed wood and fo r e s t f l o o r substrata within community types (see table 15 for community type codes). Mean seedling density/m 2 (S.D.) Community types Tsuga Thuia Abies Pseudotsuga Substrata types , _ •.-. . -, • _ i_ • n • . . . J t f heterophylla p l i c a t a amabilis menziesii P4 wood (33) 2 2.82 (6.13) 0.09 (0.38) 0.06 (0. 24) ( 5 ) 1 f l o o r (67) 1.10 (4.93) 0.10 (0.53) 0.10 (0. 47) z 3 1.40 0.15 0.62 S l g . H n. s. n. s. n.s. P5 wood (111) 3.22 (7.31) 0.37 (1.57) (13) f l o o r (149) 0.70 (2.57) 0.09 (0.51) z 3.47 1.82 s i g . *** * P6 wood (86) 17.74 (27.25) 0.80 (1.99) 0.13 (0. 50) (10) f l o o r (114) 6.36 (11.60) 0.59 (1.35) 0.14 (0. 55) z 3.63 0.85 0.17 s i g . n.s. n.s. T2 wood (63) 6.60 (9.94) 0.71 (1.90) 0.27 (1. 01) (6) f l o o r (57) 1.88 (3.84) 0.16 (0.53) 0.21 (0. 67) z 3.50 2.23 0.37 s i g . *** ** n.s. T3 wood (66) 9.05 (15.27) 5.20 (10.47) 0.82 (2. 20) (6) f l o o r (54) 1.56 (4.82) 0.30 (1.25) 0.24 (0. 97) z 3.76 3.77 1.92 s i g . *** *** * T4 wood (80) 1.00 (1.92) 0.73 (2.23) 0.05 (0. 22) (8) f l o o r (80) 0.18 (0.69) 0.04 (0.19) 0.04 (0. 19) z 3.62 2.74 0.36 s i g . *** ** n.s. A5 wood (88) 5.60 (10.97) 3.98 (6. 94) (7) f l o o r (52) 1.79 (3.37) 4.19 (7. 28) z 3.03 0.27 s i g . ** n.s. F l wood (41) 0.78 (1.85) (7) f l o o r (99) 0.07 (0.38) z 2.43 s i g . ** Number of p l o t s ; 2 Number of microplots; 3 z-value of two sample z-test 4 *** = p ^ .001; ** = .001 < p < .01; * = .01 < p « .05; n.s. = p > .05 233 Figure 1 : Study area and p l o t l o c a t i o n map. 234 Figure 2 : Climate diagrams. Abscissa i n months, ordinate with one d i v i s i o n to 10° C or 20 mm p r e c i p i t a t i o n (except 100 mm at top of diagram), A = elevation above sea l e v e l , B = distance drom the coast, C = length of record, D = mean annual temperature (°C), E = mean annual p r e c i p i t a t i o n (mm), F = highest temperature on record, G = mean d a i l y maximum of the warmest month ( J u l y ) , H = mean d a i l y minimum of the coldest month (January), I = lowest temperature on record, J = mean monthly p r e c i p i t a t i o n curve, K = mean monthly temperature curve, L ( v e r t i c a l shading, two scales) = r e l a t i v e humid season, M (dotted shading) = r e l a t i v e period of drought, N (neutral shading) = months with mean d a i l y minimum below 0°C, 0 (diagonal shading) = months with lowest temperature on record below 0°C, P = f r o s t - f r e e period. [ f o l l o w i n g Walter and L i e t h (1967), data from Atmospheric Environment Service (Anon. 1982) ]. TofinO A 495'N 125'46'W 20m 2km8 25yrs 8.9°° 3288E J F M A M J J A S O N D 235 Figure 3 : Watersheds sampled 1. Sproat Lake; 2. Cous Creek; 3. Nahmint Lake; 4. Kennedy River; 5. Estevan; 6. Cypre River; 7. China Creek; 8. Museum Creek; 9. Coleman Creek; 10. N i t i n a t River; 11. S a r i t a River; 12. Pachena River; 13. Klanawa River. i n the study area. 235a 236 Figure 4 : Microplot sampling designs. a) systematic microplot placement within 500 m2 p l o t ; b) s t r a t i f i e d random microplot placement within p l o t ; c) cover classes used i n conjunction with microplots. 237 Figure 5 : Reciprocal averaging ordination of forest vegetation data from 172 pl o t s . Variance explained i s 11.0 % by the f i r s t axis and 8.8 % by the second axis. S o l i d t r i a n g l e s ( A ) i n d i c a t e plots from the subalpine vegetation group, squares indi c a t e plots from the f l o o d p l a i n vegetation group and c i r c l e s i n d i c a t e plots from the Pinus con- t o r t a vegetation group. Community types : f l o o d p l a i n forests ( F l ) , M ; f l o o d p l a i n forests (Lysichitum variant) (F2), • ; dry Pinus-Pseudotsuga f o r e s t s (DI),# ; coastal dry Pinus f o r e s t s (D2),O ; dry Pseudotsuga fo r e s t s ( P I ) , A . Species names are approximately located where they appear in the species ordination also produced by RA. Non-c l a s s i f i e d p l o t s are represented by small dots. 237a Abies amabilis Tsuga mertensiana 116AA31 A A129 A 137 63 A30 A37 X A *•. 136 A . A34 ." / S S Pinus contorta 0 5 3 Ol69 ^ • • • \ 1& 7 0158 110 • • • • • • • • • • • • **•. _ •• ftvtV*v V v : . « # V t • . • •• A •» TO^ «:•.•• . 10 160» • • • • • 1 1 B • • • . • A111 • 161 • 171 • • 46 58 \ • • • • \ • • • • A18 • 92 \ • # • 122 Picea sitchensis • 1 2 1 . 1 .017 0 025 238 Figure 6 : Reciprocal averaging ordination of forest vegetation data from 140 p l o t s . Variance explained i s 13.6 % by the f i r s t axis and 9.8 % by the second axis. C i r c l e s (•) indicate p l o t s from the Pseudotsuga group, squares (•) indi c a t e p l o t s from the Abies group, and t r i a n g l e s ( A ) i n d i c a t e p l o t s from the Thuja group'. Species names are approximately located where they appear i n the species ordination also produced by RA. A single n o n - c l a s s i f i e d plot i s represented by a small dot. 238a A A A A Thuja plicata • • A i t ™ A A A A A A A . . . " • * . . . A D A ^ . . « * " • • • • • • _ • • U • ••••• • • ° & • • • 4 * ' • /** Tsuga heterophylla* • * • * q Pseudotsuga menziesii Abies amabilis • . , . I .08 0 07 239 Figure 7 : Reciprocal averaging ordination (a) and d i r e c t ordination (b) of 59 plo t s from the Pseudotsuga vegetation group. Variance explained i s 14.4 % by the f i r s t axis and 9.6 % by the second axis. Community types : Pseudotsuga-Thuj a-Acer f o r e s t s (P2), H ; Pseudotsuga-Linnaea forests (P3), O ; Pseudotsuga-Berberis forests (P4), A ; Tsuga-Pseudotsuga-Polystichum forests (P5), • ; montane Tsuga forests (P6), A ; montane Tsuga-Gaultheria f o r e s t s (P7), # ; added to the d i r e c t ordination, dry Pinus-Pseudotsuga forests (DI), • . Species names are approximately located where they appear i n the species ordination also produced by RA. No n - c l a s s i f i e d p l o t s are represented by small dots. The topographical gradient i s modified from Whittaker (1960). 131 . 239a 89 • 98 Acer macrophyllum l£b 166 $3 Q Po lyst ichum munitum • • 101 140 125 „ _ 117 D163 17 • » 135 27 • • D T • 133 „ O 167 • 142 132 •95 A 120 A'03 A128 A139 A130 112 A A 20 Tsuga heterophylla 145 19 Ae4 & 21 66 A 15 • O 16 11 O 138 A 8 38 • * 62 67 O109 8 • 3 2 Gaultheria shal lon 8-1 * •« 1 -.26 0 ~ST pi 139 A y ' • Z 115 / 62 112 ft a '.32 * A -j 6 4 B I— I4? 130 \ 67 130 A103 A 1 2 3 u • i " 2 • *° 27 o • : ~ A 124 141: 59 A 95 R167 9 8 D ° « : t 104 • : p A A 117D/ • - .f.l? • 166 « 5 / 1 3 1 1" A 120 • D w 1 20 110 145: 113 l e v e l ' ' ' __MNE ^ ~g ssw r idges NNE SSW lower s lopes mid A upper s l o p e s 240 Figure 8 : Reciprocal averaging ordination (a) and d i r e c t ordination (b) of 40 plo t s from the Thuja vegetation group. Variance explained i s 23.4 % by the f i r s t axis and 13.5 % by the second axis. Community types : coastal dry Thuja forests ( T l ) , # ; coastal Tsuga-Blechnum-Polystichum forests (T2), • ; coastal montane Thuja forests (T3), A ; coas t a l Thuja f o r e s t s (T4) , • ; coastal wet Thuja forests (T5), O ; added to the d i r e c t ordination, coastal dry Pinus forests (D2), c* . Species names are approximately located where they appear i n the species ordination also produced by RA. A sing l e n o n - c l a s s i f i e d p l o t i s represented by a small dot. The topographical gradient i s modified from Whittaker (1960). 2 A 154 A • 147 85 Abies amabi l is A 153 94 . 1 5 9 A 6 0 A A A A 172 24 84 72 A A 57 TO A 86 A b o M 6 ^48 77 Thuja pl icata UB A 5 4 2A 149#) O 76 5*2 A 100 73 ^ 47 150 A Dl05 42 5 5 A 49A • 50 155 D93 Tsuga heterophylla • _ 69 -.26 0 .34 A 152 A . 1 5 3 & A172. A .. * 88 5 H 147..' d 6 9 to • 74 / 169 A 72 A 2 t » KX) ft 93 tt° ^ , „ "DA86'-.% A B 4 ^ ^ 9 O0^)148\ A49 de 4 3 158 NNE NW w ssw ridges E SE ^ NNE SSW lower s lopes m i d A upper s lopes 241 Figure 9 : Reciprocal averaging ordination (a) and d i r e c t ordination (b) of 40 plo t s from the Abies vegetation group. Variance explained i s 16.7 % by the f i r s t axis and 10.3 % by the t h i r d a x is. Community types : montane Tsuga-Abies-Gaultheria forests ( A l ) , A ; montane Abies-Tsuga forests (A2),A ; montane Tsuga-Abies forests ( A 3 ) , A ; montane Abies-Streptopus f o r e s t s (A4), • ; lowland Abies forests (A5), • ; Tsuga-Gaultheria-Blechnum forests (A6), O ; Tsuga-Blechnum-Polystichum forests (A7),# . Species names are approximately located where they appear i n the species ordination also produced by RA. Non - c l a s s i f i e d p l o t s are represented by small dots. The topographical gradient i s modified from Whittaker (1960). ® Gaulther ia shal lon •82 B80 83 • * "3 164 26 • 126 •45 • 134 • 162 A b i e s a m a b i l i s • 102 26 A A 79 81 127 • 156 S 29 28 106 168 A 75 • 90 o 71 Tsuga heterophylla 56 09 ft -.35 • SO Si ® t 35 1 113 A 81 28 a \ 127 126 2 8 • 162 •'07 • 108 • 45 • 90 s • 8156 •4 •56 82 A 75 t 168 ff/ft ^78 68 j" 164 151 O 97 NNE N N E lower s lopes 8 S W NW E W S E ssw r idges mid & upper s lopes 242 Figure 10 : Reciprocal averaging ordination of 105 modal vegetation p l o t s . Variance explained i s 15.0 % by the f i r s t axis and 8.8 % by the second axis. C i r c l e s are modal plot s from the Pseudotsuga group, squares are modal plot s from the Abies group, and t r i a n g l e s are modal plot s from the Thuja group. Modal plo t s not clas-. s i f i e d into community types are represented by small dots. Community types : P 2 , © ; P3, © ; P4,3 ; P5,# ; P6,0 ; P 7 , © ; T2, A ; T3, A ; T4, • ; A3, H ; A6,D ; A7, • (see table 15 for community type codes). 242a • • • •• • • • «» O O • • ^ •oo o o • «o c ^ • o o O O © 3 O • © 0 3 9 © 3 3 © ° © e • A A A A A AA A A A • A A A A A AA A A A A A A A A A . : 1 -09 0 .08 243 Figure 11 : Relationships between species basal areas, LFH thickness/ e f f e c t i v e rooting depth r a t i o s , and distance from the coast i n 105 modal vegetation p l o t s . Polynomial regression equations for basal area (m2/ha) of species : P. menziesii = - 4.202-D + 0.261rD 2 - 0.003-D3 + 16.629 (P = .0001, F = 20.8); T_. p l i c a t a = 29.204'D - 1.801-D2 + 0.039-D3 - 0.00029-D4 - 34.556 (P.= .0001, F = 18.2); A. amabilis : = - 0.419-D + 21.76 (P = .0001, F = 29.9); T. heterophylla = - 9.538-D + 0.692-D2 - 0.0174-D3- + 0.00014-Dlt + 67.189 (P = .021, F = 3.03); LFH/E.R.D. r a t i o = - 6.185-D + 0.552-D2 - 0.0167-D3 + 0.0015-D4 + 79.906 (P = .0001, F = 13.1). D = distance from the coast i n km. distance from coast (km) 244 Figure 12 : I s o l i n e maps of vascular species richness, LFH thickness/ e f f e c t i v e rooting depth r a t i o , and climate variables within the study area [ climate maps adapted from Colidago (1980) ] . 245 Figure 13 : Canonical analyses of vegetation groups, and community types within three groups, based on environmental data. Shown are means of p l o t scores, and 90 % confidence c i r c l e s , on the f i r s t two canonical axes. Codes to vegetation groups and community types are l i s t e d i n Table 15. 245a vegetation groups Abies types 10-CV2 2996 SA u 9 T -4H CV1 38% CV2 29% 4 CV1 66% - 2 Pseudotsuga types - 8 --ioH -12H •14H CV2 18% 1 6 • 2 0 -25H - 3 0 CV1 59% 8 10 CV2 34% Thuja types * 5 • 4 2 . CV1 59% 4 0 45 50 55 246 Figure 14 : Canonical analysis of twenty-two community types and the subalpine group based on environmental data. Shown are means of plo t scores, and 90 % confidence c i r c l e s , on the f i r s t two canonical axes. Codes to community types and group are l i s t e d i n Table 15. 246a 247 Figure 15 : Tree s i z e - c l a s s structure : Pseudotsuga group community types and dry Pinus-Pseudotsuga forests (Dl). Hand-fitted and smoothed curves from the data of a l l plots within each community type. Codes to community types are l i s t e d i n Table 15. Ps = Pseudotsuga menziesii, Ts = Tsuga heterophylla, Th = Thuja p l i c a t a , P i = Pinus contorta. -1 247a 1— i ? 1 » —I—I—I 1 r »— "*—i—1| i seedlings & size-classes (10 cm) 248 Figure 16 : Tree s i z e - c l a s s structure : Thuja group community types and coastal dry Pinus forests (D2) . Hand-fitted and smoothed curves from the data of a l l p l o t s within each community type. Codes to community types are l i s t e d i n Table 15. Th = Thuja p l i c a t a , Ts = Tsuga heterophylla, Ab = Abies amabilis, P i = Pinus contorta. 249 Figure 17 : Tree s i z e - c l a s s structure : Abies group community types and coastal Tsuga-Blechnum-Polystichum forests (T2). Hand-fitted and smoothed curves from the data of a l l p l o t s within each community type. Codes to community types are l i s t e d i n Table 15. Ab = Abies amabilis, Ts = Tsuga heterophylla, Ps = Pseudotsuga menziesii. 249a - > i i " I I I 1 1 1 1 I I I seedlings ft size-classes (10cm) - i 1 r-250 Figure 18 : Community type photographs. a) montane Tsuga-Gaultheria forests (P7, plo t 32); b) Pseudotsuga-Berberis forests (P4, plo t 123); c) Tsuga-Pseudotsuga-Polystichum forests (P5, plo t 124); d) coastal Thuja forests (T4, plo t 49); e) Tsuga-Blechnum-Polystichum forests (A7, plot 91); f) lowland Abies forests (A5, plo t 162). ISO A, 251 Appendix 1 : L i s t and constancy of species found i n vegetation p l o t s . Life-form d i v i s i o n s used for shrubs and herbs (following Scoggan 1978-1979) : Phanerophytes (woody stems, perennating buds above 25 cm from ground) Ms Mesophanerophytes, 8-30 m i n height Mc Microphanerophytes, 2-8 m i n height N Nanophanerophytes, 25 cm to 2 m i n height Chamaephytes Ch (woody stems, perennating buds within 25 cm of ground) Hemicryptophytes (perennating buds at ground surface) Hp Protohemicryptophyte without runners Hpr Protohemicryptophyte with runners Hs Hemicryptophyte, semi-rosette, without runners Hsr Hemicryptophyte, semi-rosette, with runners Hr Hemicryptophyte, rosette, without runners Hrr Hemicryptophyte, rosette, with runners Cryptophytes (perennating buds or structure under ground surface) Gp Saprophytic or p a r a s i t i c geophyte Grh Rhizome geophyte, perennating bud terminating a deep rhizome Gst Stem-tuber geophyte, perennating by tubers or corms Grt Root-tuber geophyte, perennating by tuberous roots Gb Bulb geophyte, perennating by a bulb or bulbs Hel Helophyte, perennating buds and lower part of plant submersed or i n mud Therophytes (perennating as a seed) T Therophyte, plant annual 252 Trees Constancy (%) A l l p l o t s Pse. Thu. Abies Abbr. Species (172) 1 (59) (40) (40) ABA Abies amabilis (Dougl.) Forbes 59. 3 30. 5 82. 5 92. .5 ABG Abies grandis (Dougl.) Forbes 2. 3 5. 0 ACM Acer macrophyllum Pursh 13. 3 22. 0 2. .5 ALR Alnus rubra Bong. 4. 6 8. 5 2. 5 ARB Arbutus menziesii Pursh 3. 4 CHN Chamaecyparis nootkatensis (D.Don) Spach 11. 6 6. 8 7. 5 5. 0 COR Cornus n u t t a l l i i Aud. 9. 3 22. 0 PIS Picea s i t c h e n s i s (Bong.) Carr. 8. 1 12. 5 2. .5 PIC Pinus contorta Dougl. 7. 5 10. 0 PIM Pinus monticola Dougl. 9. 8 11. 8 7. 5 PSE Pseudotsuga menziesii (Mirbel) Franco 55. 2 98. 3 10. 0 30. 0 TAX Taxus b r e v i f o l i a Nutt. 22. 6 11. 8 60. 0 7. .5 THU Thuja p l i c a t a Donn. 73. 2 81. 3 95. 0 55. 0 TSH Tsuga heterophylla (Raf.) Sarg. 96. 5 100. 0 100. 0 100. 0 TSM Tsuga mertensiana (Bong.) Carr. 5. 8 3. 3 TOTAL TREE Species 15 12 10 8 1 number of plots 2 vegetation groups 253 Shrubs Abbr. Species Constancy (%) L i f e - A l l p l o t s Pse. Thu. Abies forms (172) (59) (40) (40) ACGL AMAL ARCO BENE COST GASH HODI LOCI MEFE OPHO PAMY PHYS PYUS RHAM RHHA RIBB RIBL ROGY RUPA RUSP RUUR SALI Acer glabrum Torr. Mc 2. 9 6 .7 Amelanchier a l n i f o l i a Nutt. N 8. 1 13 .5 Arctostaphylos columbiana Piper N 2. 3 Berberis nervosa Pursh N 32. 5 72 .8 7. ,5 Cornus s t o l o n i f e r a Michx. N 0. 5 Gaultheria shallon Pursh N (Mc) 68. 6 69 .4 97. ,5 50. ,0 Holodiscus d i s c o l o r (Pursh) Maxim . N (Mc) 4. 6 6 .7 Lonicera c i l i o s a (Pursh) DC. N (Mc) 1. 1 1 .6 Menziesia ferruginea Smith N (Mc) 34. 3 5 .0 85. ,0 35. ,0 Oplopanax horridus (Smith) Miq. N (Mc) 6. 9 3 .3 17. .5 Pachistima myrsinites (Pursh) Raf. N 1. 7 Physocarpus o p u l i f o l i u s (L.) Maxim. Mc 0. 5 Pyrus fusca Raf. Mc (Ms) 4. 6 15. .0 Rhamnus purshiana DC. Mc (Ms) 2. 9 1 .6 10, .0 Rhododendron alb i f l o r u m Hook. N 0. 5 Ribes bracteosum Dougl. N (Mc) 4. 0 1 .6 2, .5 Ribes lacustre (Pers.) Poir. N 2. 3 5 .0 Rosa gymnocarpa Nutt. N 17. 4 32 .2 5 .0 2, .5 Rubus p a r v i f l o r u s Nutt. Hp 4. 6 5 .0 2 .5 Rubus s p e c t a b i l i s Pursh Hpr 43. 6 16 .9 72, .5 65, .0 Rubus ursinus Cham. & Schlecht. Hpr 19. 7 44 .0 S a l i x sp. Mc 1. ,7 254 Shrubs Constancy (%) L i f e - A l l pl o t s Pse. Thu. Abies forms (172) (59) (40) (40) SAMR Sambucus racemosa L. Mc 3.4 3.3 5.0 SOSI Sorbus s i t c h e n s i s Roemer Mc 3.4 2.5 7.5 SYAL Symphoricarpos albus (L.) Blake N 5.2 11.8 + Symphoricarpos m o l l i s Nutt. Ch VAAL Vaccinium alaskaense Howell N 70.3 38.9 95.0 95.0 VAME Vaccinium membranaceum Dougl. N 4.0 3.3 2.5 VAOL Vaccinium o v a l i f o l i u m Smith N 33.1 11.8 55.0 40.0 VAOT Vaccinium ovatum Pursh N (Mc) 21.5 13.5 47.5 VAPA Vaccinium parvifolium Smith N (Mc) 99.4 100 100 100 TOTAL SHRUB Species 31 23 11 14 255 Herbs Constancy (%) Abbr. Species L i f e - A l l p l o t s forms (172) Pse. (59) Thu. (40) Abies (40) ACHI A c h i l l e a m i l l e f o l i u m L. Hsr 1.1 ACTR Achlys t r i p h y l l a (Smith) DC. Grh 51.7 86.4 2. 5 52.5 ADBI Adenocaulon b i c o l o r Hook. Hs 10.4 13.5 12.5 ADPE Adiantum pedatum L. Grh 12.7 18.6 15.0 AGAL Agrostis sp. Hs 1.1 AGSC Agrostis hyemalis (Walt.) BSP. Hs 2.3 ALVI A l l o t r o p a v i r g a t a T. & G. Gp 5.8 13.5 ANLY Anemone l y a l l i i B r i t t . Grh 2.3 5.0 ANNE Antennaria neglecta Greene Ch 0.5 APAN Apocynum androsaemifolium L. Grh (Hp) 2.9 1.6 ARCE Arceuthobium campylopodum Engelm. parasite ARUV Arctostaphylos uva-ursi (L.)Spreng. Ch 1.1 AREN Arenaria macrophylla Hook. Hpr 2.9 3.3 ARUY Aruncus Sylvester Kostel Hp 3.4 1.6 ASTR Asplenium trichomanes L. Hr 0.5 1.6 ATFI Athyrium f i l i x - f e m i n a (L.) Roth. Hr 22.0 11.8 10. 0 40.0 BLSP Blechnum spicant (L.) Roth. Hr 63.9 33.8 100 87.5 BOHO Boschniakia hookeri Walpers Gp 11.0 11.8 12. 5 BOMU Botrychium multifidum (Gmel.) Trevis Grh 0.5 2. 5 BOVI Botrychium virginianum (L.) Swartz Grh 0.5 1.6 BOYE Boykinia e l a t a (Nutt.) Greene Hs 5.8 1.6 5. 0 7.5 BROV Bromus v u l g a r i s (Hook.) Shear Hs 4.6 6.7 CALA Calamagrostis nutkaensis (Presl) Steud. Hsr 1.7 7. 5 256 Herbs Constancy (%) L i f e - A l l p l o t s Pse. Thu. Abies forms (172) (59) (40) (40) CALY Calypso bulbosa (L.) Oakes Gst 4.6 11.8 CAMP Campanula s c o u l e r i Hook. Hpr 5.8 11.8 CARD Carex deweyana Schw. Hs 0.5 CARH Carex hendersonii Bailey Hs 1.7 1.6 CARI Carex laeviculmis Meinsh. Hs 0.5 2. 5 CARL Carex l e p t a l e a Wahl. Hsr 0.5 2. 5 CARM Carex mertensii Prescott Grh 0.5 2. 5 CARO Carex obnupta Bailey Grh 5.2 15. 0 CARR Carex sp. 1 0.5 2. 5 CARS Carex sp. 2 0.5 2. 5 CHME Chimaphila menziesii (R.Br.) Spreng. Hpr 22.0 40.6 12. 5 CHUM Chimaphila umbellata (L.) Bart. Hpr 20.3 37.2 10. 0 CIRC Circaea alpina L. Grh 0.5 CLUN C l i n t o n i a u n i f l o r a (Schult.) Kunth. Grh 6.3 1.6 10. 0 COAA Collomia heterophylla Hook. T 0.5 COAS Coptis a s p l e n i f o l i a S a l i s b . Hrr 6.9 15. 0 12. 5 COMA Co r a l l o r h i z a maculata Raf. Grh 6.9 10.1 7. 5 COME Co r a l l o r h i z a mertensiana Bong. Grh 13.9 27.1 2. 5 5. 0 CORN Cornus canadensis L. Hpr 23.8 6.7 45. ,0 27. 5 CRCR Cryptogramma c r i s p a (L.) R. Br. Hr 1.7 CYST Cystopteris f r a g i l i s (L.) Bernh. Hr 0.5 2. 5 DASP Danthonia spicata (L.) Beauv. Hs 4.6 DESC Deschampsia caespitosa (L.) Beauv. Hs 0.5 2. ,5 257 Herbs DICE Dicentra formosa (Andr.) Walp. DIHO Disporum hookeri (Torr.) Nicholson DISM Disporum s m i t h i i (Hook.) Piper DRAU Dryopteris a u s t r i a c a (Jacq.) Woynar EQTE Equisetum telmateia Ehrh. ERLA Eriophyllum lanatum (Pursh) Forbes FEOC Festuca o c c i d e n t a l i s Hook. FEOV Festuca ovina L. FESA Festuca subulata T r i n . FESU Festuca s u b u l i f l o r a Scribn. FRAG Fragaria v i r g i n i a n a Duchesne FRIT F r i t i l l a r i a camschatcensis (L.) Ker-Gawl. GALI Galium t r i f l o r u m Michx. GAOV Gaultheria o v a t i f o l i a Gray GOOB Goodyera o b l o n g i f o l i a Raf. GYDR Gymnocarpium dryopteris (L.)Newm. HADI Habenaria d i l a t a t a (Pursh) Hook. HAEL Habenaria elegans (Lindl.) Boland. HASA Habenaria saccata Greene HASP Habenaria sp. HECO Hemitomes congestum Gray HEMI Heuchera micrantha Dougl. HIAL Hieracium a l b i f l o r u m Hook. HYPA Hypochaeris r a d i c a t a L. Constancy (%) L i f e - A l l p l o t s Pse. Thu. Abies forms (172) (59) (40) (40) Grh 0.5 1.6 Grh 8.1 15.2 5.0 Grh 1.7 1.6 5.0 Hr (Grh) 16.8 10.1 7.5 37.5 Grh 1.1 5.0 Hp 0.5 Hs 7.5 11.8 Hs 1.1 Hs 1.7 Hs 17.4 42.3 2.5 2.5 Hrr 2.3 Gb 1.1 Hp 13.3 11.8 5.0 15.0 Ch 3.4 3.3 2.5 Hrr 37.7 55.9 12.5 15.0 Grh 7.5 20.0 Grt 0.5 2.5 Grt 0.5 Grt 0.5 2.5 Grt 0.5 Gp 7.5 13.5 5.0 Hr 0.5 1.6 Hs 6.9 8.4 2.3 258 Herbs Constancy (%) L i f e - A l l p l o t s Pse. Thu. Abies forms (172) (59) (40) (40) HYPO Hypopitys monotropa Crantz Gp 19.1 23. 7 25.0 LAMU Lactuca muralis (L.) Fresen. 12.7 27. 1 5.0 LANE Lathyrus nevadensis Wats. Grh 2.3 6. 7 LIAO Li l i u m columbianum Hanson Gb 2.9 1. 6 LIBO Linnaea b o r e a l i s L. Ch 35.4 50. 8 30 .0 7.5 LICA L i s t e r a caurina Piper Grh 23.8 15. 2 20 .0 40.0 LICO L i s t e r a cordata (L.) R. Br. Grh 39.5 49. 1 45 .0 22.5 LUPI Lupinus sp. 0.5 LUZC Luzula campestris (L.) DC. Hs 1.1 LUZP Luzula p a r v i f l o r a (Ehrh.) Desv. Hs 8.1 1. 6 2 .5 10.0 LYCL Lycopodium clavatum L. Ch 4.0 3. 3 5 .0 2.5 LYSE Lycopodium selago L. Ch 2.9 1. 6 2 .5 2.5 LYSI MAAD Lysichitum americanum Hulten & St.John Madia madioides (Nutt.) Greene Grh Hs 6.3 1.1 17 .5 2.5 MAD I MECU Maianthemum dilatatum (Wood) Nels. & Macbr. Melica subulata (Griseb.) Scribn. Grh Gst 31.3 3.4 8. 1. 4 6 55 .0 35.0 MIOV M i t e l l a o v a l i s Greene Hrr 2.9 5 .0 2.5 MONE Moneses u n i f l o r a (L.) Gray Hr 4.6 3. 3 5 .0 10.0 MONO Monotropa u n i f l o r a L. Gp 6.9 16. 9 2.5 MOPA Montia p a r v i f o l i a (Moc.) Greene Hsr 4.0 10. 1 MOSI Montia s i b i r i c a (L.) Howell T (Hs) 3.4 5. 0 2.5 NEPH Nephrophyllidium c r i s t a - g a l l i (Menzies) G i l g . Grh (Hel) 0.5 2 .5 259 Herbs Constancy (%) L i f e - A l l p l o t s Pse. Thu. Abies forms (172) (59) (40) (40) OXOR Oxalis oregana Nutt. 1.1 PAOC Panicum occidentale Scribn. Hs 0.5 PEDI Pe d i c u l a r i s racemosa Dougl. Hp 1.1 1. ,6 PENS Penstemon da v i d s o n i i Greene Ch 0.5 PENT Penstemon serrulatus Menzies Hp (Ch) 0.5 2. ,5 PHYL Phyllodoce empetriformis (Sw.) D.Don Ch 1.1 PLER Pleuropogon refractus (Gray) Benth. Hs 0.5 POAM Poa marcida Hitchc. Hs 2.9 5 .0 POLY Polypodium g l y c y r r h i z a D.C. Eat. Grh 20.3 33 .8 7. 5 2 .5 POMU Polystichum munitum (Kaulf.) P r e s l Hr 71.5 89 .8 35. 0 80 .0 PRAL Prenanthes a l a t a (Hook.) D. D i e t r . Hp 1.7 2. 5 5 .0 PRUN Prunella v u l g a r i s L. Hsr 1.1 2. 5 PTAQ Pteridium aquilinum (L.) Kuhn Grh 16.2 33 .8 5 .0 PTEA Pterospora andromedea Nutt. Gp 2.3 6 .7 PYAP Pyrola aphylla Smith Hrr 1.1 3 .3 PYAS Pyrola a s a r i f o l i a Michx. Hrr 2.3 1 .6 2 .5 PYPI Pyrola p i c t a Smith Hrr 9.8 18 .6 5 .0 PYSE Pyrola secunda L. Hrr 8.7 3 .3 15 .0 RUNI Rubus n i v a l i s Dougl. Hpr 0.5 1 .6 RUPE Rubus pedatus J.E. Smith Hpr 16.8 1 .6 10. 0 37 .5 SAXF Saxifraga ferruginea Graham Hr 2.9 SEWA Se l a g i n e l l a w a l l a c e i Hieron. Ch 4.6 3 .3 SMRA Smilacina racemosa (L.) Desf. Grh 4.0 10 .1 260 Herbs Constancy (%) L i f e -forms A l l p l o t s (172) Pse. (59) Thu. (40) Abies (40) SMST Smilacina s t e l l a t a (L.) Desf. Grh 4.0 5.0 7.5 STAC Stachys cooleyae H e l l e r Gst 2.3 1.6 STEN Stenanthium occidentale Gray Gb 0.5 1.6 STRA Streptopus amplexifolius (L.) DC. Grh 23.2 6.7 27. 5 35.0 STRR Streptopus roseus Michx. Grh 13.3 5.0 35.0 STRS Streptopus streptopoides (Ledeb.) Frye & Rigg Grh 6.9 17.5 TILA T i a r e l l a l a c i n i a t a Hook. Hsr 40.1 35.5 37. 5 52.5 TITR T i a r e l l a t r i f o l i a t a L. Hsr 51.1 49.1 40. 0 67.5 TIUN T i a r e l l a u n i f o l i a t a Hook. Hsr 1.1 2.5 TOME Tolmiea menziesii (Pursh) T. & G. Hsr 1.1 TRAU Trautv e t t e r i a c a r o l i n i e n s i s (Walt.) V a i l Grh 10.4 1.6 22.5 TRIE T r i e n t a l i s a r c t i c a F i s c h . Hpr 0.5 2. 5 TRLA T r i e n t a l i s l a t i f o l i a Hook. Gst 20.3 45.7 TROV T r i l l i u m ovatum Pursh Grh 45.9 47.4 32. 5 65.0 TRMA Trisetum canescens Buckl. Hs 0.5 TRMC Trisetum cernuum T r i n . Hs 2.3 VEVI Veratrum v i r i d e A i t . Grh 10.4 15. ,0 7.5 VIGL V i o l a g l a b e l l a Nutt. Hsr 6.3 1.6 5. ,0 5.0 VIOR V i o l a o r b i c u l a t a Geyer Hs 1.7 2.5 VISE V i o l a sempervirens Greene Hsr 22.0 33.8 5. ,0 15.0 ZYVE Zigadenus venenosus Wats. Gb 0.5 TOTAL HERB Species 135 78 47 63 261 Mosses Constancy (%) A l l p l o t s Pse. Thu. Abies Abbr. Species (172) (59) (40) (40) ANDR Andreaea r u p e s t r i s Hedw. 1.1 ANT I A n t i t r i c h i a curtipendula (Hedw.) Br i d . 1.1 2. 5 2, .5 BUXB Buxbaumia p i p e r i Best 1.7 1. 6 CAMY Campylopus atrovirens De Not. 1.1 CLOA Claopodium c r i s p i f o l i u m (Hook.) Ren. &Card. 4.6 8. 4 5, .0 DICF Dicranum fuscescens Turn. 59.3 77. 9 40. 0 52, .5 DICM Dicranum majus Sm. 1.1 5. 0 DICS Dicranum scoparium Hedw. 8.1 3. 3 7. 5 DITR Ditrichum sp. 0.5 EURP Eurhynchium pulchellum (Hedw.) Jenn. var. b a r n e s i i (Ren. & Card.) Crum, Steere & Anders. 2.3 7 .5 HETE Heterocladium macounii Best 17.4 28. 8 10. 0 15 .0 HETP Heterocladium procurrens (Mitt.) Rau & Herv. 1.1 1. 6 HOLU Hookeria lucens (Hedw.) Sm. 43.0 11. 8 87. 5 60 .0 HYLO Hylocomium splendens (Hedw.) B.S.G. 78.4 89. 8 85. 0 55 .0 HYPU Hypnum c i r c i n a l e Hook. 64.5 84. 7 47. 5 65 .0 HYPV Hypnum d i e c k i i Ren. & Card, ex R o e l l . 0.5 2. 5 HYPP Hypopterygium f a u r i e i Besch. 1.1 1. 6 2 .5 I SOP Isopterygium elegans (Brid.) Lindb. 43.0 44. 0 32. 5 52 .5 ISST Isothecium stoloniferum Brid. 72.0 74. 5 80. .0 87 .5 LEME Leucolepis menziesii (Hook.) Steere 16.2 20. 3 5. 0 12 .5 ex L. Koch 262 Mosses Constancy (%) A l l p l o t s Pse. Thu. Abies (172) (59) (40) (40) META Metaneckera menziesii (Hook, ex Drumm.) 0.5 1.6 Steere MNIU Mnium spinulosum B.S.G. 13.3 25.4 MNIV Mnium thompsonii Schimp. 0.5 PLIN Plagiomnium insigne (Mitt.) Kop. 8.1 8.4 PLUN Plagiothecium undulatum (Hedw.) B.S.G. 75.5 57.6 PLZS Pleurozium schreberi (Brid.) M i t t . 3.4 1.6 POGM Pogonatum alpinum (Hedw.) Rohl. 20.9 37.2 var. sylvaticum (Hoppe) Lawt. POGC Pogonatum contortum (Brid.) Lesq. 6.9 PONC Polytrichum commune Hedw. 4.0 PONF Polytrichum formosum Hedw. 0.5 PONJ Polytrichum juniperinum Hedw. 5.8 1.6 PONP Polytrichum p i l i f e r u m Hedw. 2.9 1.6 PORO Porotrichum b i g e l o v i i ( S u l l . ) Kindb. 0.5 RHAA Rhacomitrium aquaticum (Brid. ex_ Schrad.) 1.7 Brid. RHAC Rhacomitrium canescens (Hedw.) Br i d . 3.4 RHAH Rhacomitrium heterostichum (Hedw.) Br i d . 6.9 5.0 RHAL Rhacomitrium lanuginosum (Hedw.) Br i d . 2.3 RHGL Rhizomnium glabrescens (Kindb.) Kop. 67.4 47.4 RHLO Rhytidiadelphus loreus (Hedw.) Warnst. 88.9 83.0 RHTR Rhytidiadelphus tr i q u e t r u s (Hedw.) Warnst. 9.8 20.3 RHYT Rhytidiopsis robusta (Hook.) Broth. 28.4 44.0 ROEL R o e l l i a r o e l l i i (Broth.) Andr. ex Crum 0.5 97.5 5.0 2.5 97.5 95.0 2.5 2.5 2.5 92.5 15.0 1.6 7.5 17.5 2.5 2.5 2.5 5.0 80.0 85.0 27.5 2.5 263 Mosses Constancy (%) A l l p l o t s Pse. Thu. Abies (172) (59) (40) (40) SCLE Scleropodium t o u r e t t e i (Brid.) L. Koch 0.5 SPHF Sphagnum f a l l a x (Klinggr.) Klinggr. 0.5 2 .5 SPHG Sphagnum girgensohnii Russ. 9.3 22 .5 12. 5 SPHH Sphagnum henryense Warnst. 2.3 5 .0 SPHP Sphagnum papillosum Lindb. 0.5 2 .5 SPHS Sphagnum squarrosum Crome 0.5 2 .5 STOR S t o k e s i e l l a oregana ( S u l l . ) Robins. 79.6 93. 2 97 .5 62. 5 STPR S t o k e s i e l l a praelonga (Hedw.) Robins. 4.0 2 .5 TIMM Timmia austriaca Hedw. 0.5 1. 6 TAME Trachybryum megaptilum (Sull.) Schof. 15.6 32. 2 2. .5 TOTAL MOSS Species 52 30 25 29 264 Liverworts Constancy (%) A l l p l o t s Pse. Thu. Abies Abbr. Species (172) (59) (40) (40) BAZZ Bazzania denudata (Torr. ex Gott.) Trev. 12.7 3. 3 32.5 15.0 BLET Blepharostoma trichophyllum (L.) Dum. 10.4 3. 3 20.0 15.0 CALF Calypogeia f i s s a (L.) Raddi 0.5 2.5 CALM Calypogeia muellerana (Schiffn.) K. Muell. 8.7 1. 6 22.5 10.0 CEPH Cephalozia bicuspidata (L.) Dum. 31.3 11. 8 60.0 50.0 COCO Conocephalum conicum (L.) Dum. ex Lindb. 3.4 2.5 5.0 DIPA Diplophyllum albicans (L.) Dum. 11.6 1. 6 27.5 12.5 DIPP Diplophyllum plicatum Lindb. 2.9 12.5 HEBA Herbertus aduncus (Dicks.) S. Gray 6.3 1. 6 17.5 JULE Jungermannia leiantha G r o l l e 1.1 5.0 KURZ Kurzia sp. 1.7 7.5 LEDO Lepidozia reptans (L.) Dum. 9.3 10. 1 5.0 17.5 MARS Marsupella emarginata (Ehrh.) Dum. 0.5 METZ Metzgeria conjugata Lindb. 1.1 1. 6 2.5 MYTA Mylia t a y l o r i i (Hook.) S. Gray 3.4 12.5 NASC Nardia s c a l a r i s S. Gray 1.7 5.0 PELI P e l l i a neesiana (Gott.) Limpr. 12.7 25.0 12.5 PLAG P l a g i o c h i l a p o r e l l o i d e s (Torr. ex Nees) Lindenb. 30.8 11. ,8 52.5 42.5 PORE P o r e l l a r o e l l i i Steph. 0.5 2.5 PTIC P t i l i d i u m californicum (Aust.) Underw. 1.1 1, .6 2.5 PTIP P t i l i d i u m pulcherrinum (G. Web.) Hampe 0.5 RICL Ricca r d i a l a t i f r o n s Lindb. 10.4 30.0 10.0 265 Liverworts RICM Ri c c a r d i a m u l t i f i d a (L.) S. Gray SCAA Scapania americana K. Muell. SCAB Scapania bolanderi Aust. SCAP Scapania paludosa (K. Muell.) K. Muell. TOTAL LIVERWORT Species Constancy (%) A l l p l o t s Pse. Thu. Abies (172) (59) (40) (40) 0.5 2.5 1.1 83.1 89.8 77.5 90.0 0.5 2.5 26 11 22 12 266 Lichens Constancy (%) A l l p l o t s Pse. Thu. Abies Abbr. Species (172) (59) (40) (40) CLAS Cladina impexa (Harm.)B. de Lesd. CLAR Cladina r a n g i f e r i n a (L.) Harm. CLEA Cladonia acuminata (Ach.) N o r r l . CLDB Cladonia b e l l i d i f l o r a (Ach.) Schaer. CLDP Cladonia chlorophaea (Flk.) Spreng. CLEC Cladonia furcata (Huds.)Schrad. CLDG Cladonia g r a c i l i s (L.) W i l l d . CLDF Cladonia multiformis Merr. CLEB Cladonia pyxidata (L.) Hoffm. CLDS Cladonia squamosa (Scop.) Hoffm. CLDU Cladonia u n c i a l i s (L.) Wigg. LOBA Lobaria l i n i t a (Ach.) Rabh. Lobaria oregana (Mull. Arg.) Hale P e l t i g e r a aphtosa (L.) W i l l d . PELO P e l t i g e r a leucophlebia (Nyl.) Gyeln. P e l t i g e r a membranacea (Ach.) Nyl. PELT P e l t i g e r a polydactyla (Neck.) Hoffm. P e l t i g e r a praetextata (Somm.) Vain. STEO Stereocaulon subcoralloides Nyl. STET Stereocaulon tomentosum Fr. TOTAL LICHEN Species 20 3.4 3.3 5.8 1.6 0.5 1.6 5.2 1.6 0.5 0.5 4.0 4.0 0.5 1.1 2.9 2.3 5.0 0.5 1.6 1.7 5.2 5.0 2.5 6.9 10.1 5.0 11.6 20.3 10.0 0.5 2.5 2.9 1.1 TOTAL VASCULAR PLANT Species 181 113 68 85 TOTAL NON-VASCULAR PLANT Species 98 50 47 45 TOTAL PLANT Species 279 163 115 130 267 Appendix 2 : Environmental data d e s c r i p t i v e s t a t i s t i c s for vegetation groups and community types. L i s t of variables (refer to Table 1 for d e f i n i t i o n s of classes for d i s c r e t e v a r i a b l e s * ) : 1 - ele v a t i o n (m) 2 - aspect (0 - 180 , NNE to SSW) 3 - slope (%) 4 - topographic p o s i t i o n (1-6)* 5 - drainage (1-7)* 6 - e f f e c t i v e rooting depth (cm) 7 - root r e s t r i c t i n g depth (cm) 8 - s o i l depth (cm) 9 - s u r f i c i a l material (0-4)* 10 - e f f e c t i v e rooting depth/root r e s t r i c t i n g depth 11 - e f f e c t i v e rooting depth/soil depth 12 - LFH t h i c k n e s s / e f f e c t i v e rooting depth 13 - f i r e disturbance (0-1)* 14 - wind disturbance (0-1)* 15 - worms (0-3)* 16 - LFH pH (H 20) 17 - LFH pH (CaCl 2) 18 - LFH thickness (cm) 19 - A pH (H 20) 20 - A pH (CaCl 2) 21 - Bx pH (H 20) 22 - Bi pH (CaCl 2) 23 - B i % coarse fragments 24 - D\ texture (1-12)* 25 - B i % N 26 - Bx % C 27 - Bi C/N r a t i o 28 - B 2 pH (H 20) 29 - B 2 pH (CaCl 2) 30 - LFH % C 31 - LFH % N 32 - LFH C/N r a t i o Slope classes (C.S.S.C., 1978) % slope terminology < 2.5 l e v e l 2-5 very gentle slopes 6-9 gentle slopes 10-15 moderate slopes 16-30 strong slopes 31-45 very strong slopes 46-70 extreme slopes 71-100 steep slopes > 100 very steep slopes (Note : va r i a b l e 15 cannot be interpreted from these data since i t was not recorded i n 1980 p l o t s , and these are included i n these s t a t i s t i c s ) Appendix 2 : Subalpine vegetation group (SA) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 11 485.00 1050.0 788.91 188.44 2 .ASPECT 11 18.OOO 156.00 71.000 41 . 156 3 .SLOPE 11 27.000 60.OOO 41.000 12.141 4 .POSIT 11 2.0000 3.0000 2.7273 .46710 5 .DRAINAGE 11 2.0000 5.0000 3. 1818 .98165 6 EROOTDEP 11 13.000 69.OOO 40.364 17.996 7 ROOTDEP 11 19.000 104.00 63.545 24.039 6 SOILDEP 11 19.000 148.00 85.364 36.21 1 9 MATERIAL 11 1.0000 2.0000 1.4545 .52223 10 RATI01 11 .15000 1.0000 .70182 .29549 1 1 RATI02 11 .90000 -1 1.0000 .56273 .29018 12 RATI03 11 .60000 -1 1.0000 .38455 .39853 13 FIRE 11 0. 1.0000 .72727 .46710 14 WIND 11 0. 1.0000 .90909 -1 .30151 15 WORMS 11 0. 2.0000 .81818 .98165 16 ORGPHWAT 10 3.4000 4.3000 3.7300 .24967 17 ORGPHCAL 10 2.9000 3.8000 3.2400 .25906 18 ORGTHICK 11 2.0000 35.000 11 .818 10.177 19 APHWAT 3 3.5000 3.9000 3.7333 .20817 20 APHCAL 3 2.9000 3.4000 3.2000 .26458 21 B1PHWAT 10 3.8000 4.9000 4.4100 .37845 22 B1PHCAL 10 3.2000 4.4000 3.9100 .37845 23 COARSE% 11 20.000 90.000 50.455 23.922 24 TEXTURE 10 3.0000 9.0000 4.5000 1.9579 25 B1V.N 10 .90000 -1 .22000 .13700 .39735 -1 26 BT/.C 10 2.3000 14.030 5.5280 3.2535 27 B1CNRAT 10 25.600 63.200 38.210 10.598 28 B2PHWAT 8 4.6O0O 5'. 3000 5.0125 .26424 29 B2PHCAL 8 4.1000 5.0000 4.5375 .29731 30 ORG%C 10 37.600 52.200 47.743 4.4627 31 ORG'/,N 10 .64000 1.3200 .91000 .21970 32 ORGCNRAT 10 35.800 70.200 54.420 10.024 Appendix 2 : Pinus contorta vegetation group (D) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 .ELEV 7 45.000 322.OO 156.71 117.01 2 .ASPECT 7 46.000 167.00 103.86 41.611 3 .SLOPE 7 10.000 65.000 37.143 19.334 4 .POSIT 7 1.0000 1.0000 1.OOOO 5 .DRAINAGE 7 1.OOOO 1.0000 1.0000 6 .EROOTDEP 7 3.0000 23.000 12.857 8.4346 7 .ROOTDEP 7 3.0000 23.000 12.857 8.4346 8 .SDILDEP 7 3.0000 23.000 12.857 8.4346 9 .MATERIAL 7 0. 1.0000 .28571 .48795 10 .RATI01 7 1.0000 1 .0000 1.OOOO 1 1 .RATI02 7 1.0000 1 .OOOO 1.0000 12 .RATI03 7 .13000 1 .0000 .46857 .38133 13 .FIRE 7 0. 1.0000 .42857 .53452 14 .WIND 7 0. 1.0000 .42857 .53452 15 .WORMS 7 0. 0. 0. 16 .ORGPHWAT 7 3.8000 4.4000 4.0429 . 19881 17 .ORGPHCAL 7 3.3000 4.0000 3 .6143 .25448 18 .ORGTHICK 7 1.0000 14.000 4 .4286 4 .4668 19 .APHWAT 1 3.8000 3.8000 3.8000 20 .APHCAL 1 3.2000 3.2000 3.2000 21 .B1PHWAT 5 4.2000 5.4000 4.7600 .43359 22 .B1PHCAL 5 3.7000 4.7000 4.1800 .38987 23 .COARSE"/. 7 0. 95.000 40.571 41.016 24 .TEXTURE 5 2.OOOO 6.0000 4.2000 1 .7889 25 .B1%N 5 .20000 .36000 .28000 .58310 -1 26 ,B1%C 5 3.1000 15.620 8.3240 4.7100 27 . B 1CNRAT 5 15.300 43.500 28.080 11.107 28. .B2PHWAT 0 29. B2PHCAL 0 30. ORG%C 7 36.150 49.760 44.830 4.7782 31 . ORG°/.N 7 .48000 .88000 .63571 .13794 32. ORGCNRAT 7 48.200 100.10 73.871 19.842 270 Appendix 2 : Floodplain vegetation group (F) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 10 15.000 95.000 47.900 37.563 2 .ASPECT 10 0. 107.00 19.300 40.988 3 .SLOPE 10 0. 5.0000 2.1000 2.0790 4 .POSIT 10 5.0000 5.0000 5.0000 5 .DRAINAGE 10 4 OOOO 7.0000 4.9000 1.1972 6 .EROOTDEP 10 11.000 113.00 55.000 29.728 7 .ROOTDEP 10 11.000 130.00 72.500 42.009 8 .SOILDEP 10 62.000 130.00 96.100 18.947 9 .MATERIAL 10 3.0000 4.0000 3.5000 .52705 10 .RATI01 10 .61000 1.0000 .82600 .16304 1 1 .RATI02 10 .1OO00 .87000 .56000 .22730 12 .RATIOS 10 .30000 -1 .19000 .77000 -1 .61653 13 .FIRE 10 0. 1.0000 .30000 .48305 14 .WIND 10 0. 1.0000 .50000 .52705 15 .WORMS 10 0. 3.0000 2.0000 1.0541 16 .ORGPHWAT 10 4.2000 5.6000 4.7900 .38427 17 .ORGPHCAL 10 3.9000 5.1000 4.4000 .35277 18 .ORGTHICK 10 1.0000 10.000 3.4000 2.6750 19 .APHWAT 8 4.0000 5.7000 4.8375 .63005 20 . APHCAL 8 3.6000 5.4000 4.4000 .62564 2 1 .B1PHWAT 10 4.3000 5.9000 5.1600 .51467 22 .B1PHCAL 10 3.7000 5.4000 4.4800 .49621 23 .COARSE% 10 0. 10.000 1.0000 3. 1623 24 .TEXTURE 10 3.0000 10.000 5.3000 2.8304 25. .B1%N 10 .60000 -1 .30000 .20800 .79833 26 . B1%C 10 1.0200 7.2000 4.2130 2.0890 27. B1CNRAT 10 16.700 28.200 19.860 4. 1743 28. B2PHWAT 10 4.5000 6.1000 5.29O0 .45570 29. B2PHCAL 10 3.9000 5.5000 4.6200 .48028 30.0RG%C 10 25.210 49.200 38.552 6.8562 3'1 . DRG%N 10 .48000 1.0000 .71200 .16295 32. ORGCNRAT 10 34.200 70.400 55.770 11.652 Appendix 2 : Pseudotsuga vegetation group (P) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 59 15.OOO 805.00 344.71 195. 15 2 .ASPECT 59 0. 178.00 108.88 58.283 3 .SLOPE 59 4.0000 80.OOO 46.085 20.761 4 .POSIT 59 1.0000 5.0000 3. 1525 .73844 5 .DRAINAGE 59 1.0000 4.OOOO 2.4746 .79559 6 .EROOTDEP 59 8.0000 128.00 57.932 32.400 7 .ROOTDEP 59 15.000 128.00 78.644 26.835 3 .SOILDEP 59 15.000 164.00 86.508 31.111 9. MATERIAL 59 0. 3.0000 1 .3051 .70109 10, .RATI01 59 .100O0 1.OOOO .74119 .27768 11 . RATI02 59 .60000 -1 1.OOOO .70153 .29389 12, .RATI03 59 .30000 -1 1.0000 .22458 .22897 13 , FIRE 59 0. 1.0000 .83051 .37841 14 . WIND 59 0. 1.0000 .16949 -1 .13019 15 , WORMS 59 0. 3.OOOO .94915 1.0073 1G. , DRGPHWAT 58 3.2000 5.7000 4.1138 .59011 17 . CRGPHCAL 58 2.70O0 5.4000 3.6534 .61991 18 , ORGTHICK 59 1.0000 23.000 8.4407 4.6024 19 . APHWAT 7 3.8000 5.2000 4.3000 .54772 20. APHCAL 7 3.20O0 4.8000 3.7286 .56484 21 . SfPHWAT 56 3.5000 6.0000 4 .9143 .43918 22 . E1PHCAL 56 3.0000 5.4000 4.3214 .40842 23. COARSE'/. 59 5.0000 100.00 60.169 23.717 24 , TEXTURE 56 1.0000 10.OOO 3.9286 1 .9896 25. ,B1%N 56 .40000 -1 .35000 .14018 .70362 -1 26 .B17.C 56 1.3000 14 .440 4.6812 2.3227 27 .B1CNRAT 56 15.300 94.300 36.668 17.234 28 . B2PHWAT 49 4.6000 6.6000 5.1959 .39049 29 .B2PHCAL 49 4.1000 5.7000 4.6184 .38225 30 . 0RG7.C 58 27.010 56.200 45.255 5.9177 31 . 0RG'/.N 58 .48000 1.5600 .86517 .21904 32 .ORGCNRAT 58 32.000 104.40 55.093 14.307 272 Appendix 2 : Thuja vegetation group (T) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 ELEV 40 15.000 610.00 173 OO 155.56 2 . ASPECT 40 0. 169.00 76.450 53.926 3 .SLOPE 40 O. 96.000 29.900 20.836 4 .POSIT 40 1.0000 6.0000 3.5000 1.1094 5 .DRAINAGE 40 1.0000 7.OOOO 4.5500 1.4667 6 .EROOTDEP 40 5.0000 110.00 31.025 22.564 7 .ROOTDEP 40 10.000 133.00 54.575 30.609 8 .SOILDEP 40 10.000 158.00 85.325 37.376 9 .MATERIAL 40 0. 4.0000 2.0500 .87560 10 .RATI01 40 .60000 -1 1.OOOO .64550 .30860 11 .RATI02 40 .40000 -1 1.OOOO .41225 .254 14 12 .RATI03 40 .50000 - 1 1.0000 .65650 .33312 13 FIRE 40 0. 1.OOOO .12500 .33493 14 .WIND 40 0. 1.OOOO .82500 .38481 15 WORMS 40 0. 3.OOOO 1.2500 1.0064 16. ORGPHWAT 40 3.5000 4.8000 4.0875 .36033 17. ORGPHCAL 40 2.9000 4.4000 3.5650 .37795 18 . ORGTHICK 40 1.OOOO 43.OOO 16.775 9.6383 19. APHWAT 19 3.8000 5.5000 4.3263 .50973 20. APHCAL 19 3.1000 5.2000 3.7947 .52332 2 1 . B1PHWAT 38 3.8000 6.OOOO 4.6816 .39171 22 . B1PHCAL 38 3.5000 5.4000 4.1447 .38952 23. COARSE0/. 40 0. 95.OOO 36.650 25.081 24 . TEXTURE 37 2.0000 12.000 4.9459 2.2724 25. B1°/,N 38 .20000 - 1 .86000 .21395 .13689 26. B1%C 38 .18000 24.410 6.8100 4.1899 27. B1CNRAT 38 10.000 52.900 31 .679 8. 1741 28. B2PHWAT 32 4.2000 5.3000 4.8781 .28707 29. B2PHCAL 32 3.7OOO 5.2000 4.3844 .38530 30. 0RG%C 40 32.300 51.950 43.891 5.1019 31 . ORGXN 40 .54000 1.5400 .99700 .23247 32. ORGCNRAT 40 27.800 77.600 46.367 12.291 Appendix 2 : Abies vegetation group (A) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 40 25.000 915.00 355.72 235.33 2 .ASPECT 40 0. 172.00 57.925 51.816 3 .SLOPE 40 3 .OOOO 80.OOO 38.800 22.253 4 .POSIT 40 2.0000 5.0000 3.4250 .81296 5, DRAINAGE 40 2.0000 6.OOOO 3.6500. 1.0754 6, .EROOTOEP 40 5.0000 109.OO 33.350 25.077 7 .RDOTDEP 40 11.000 134.00 61.400 29.846 8 . SDILDEP 40 17.000 196.00 96.400 32.762 9. . MATERIAL 40 1.0000 3.0000 1 .7250 .71567 10. .RATI01 40 .12000 1.0000 .57850 .30590 1 1 . RATI02 40 .50000 -1 1.0000 .38250 .28372 12 . RATIOS 40 .40000 -1 1.OOOO . 58375 .34013 13 .FIRE 40 0. 1.OOOO .30000 .46410 14 .WIND 40 0. 1.0000 .40000 .49614 15 .WORMS 40 0. 3.0000 1.1750 1.1297 16 . ORGPHWAT 40 3.OOOO 6.2000 3.7500 .53060 17 . ORGPHCAL 40 2.4000 5.4000 3.1875 .53166 18 ORGTHICK 40 3.0000 27.000 13.225 5.8287 19, .APHWAT 20 3.5000 6.2000 3.9750 .62228 20 .APHCAL 20 3.0000 5.4000 3.3800 .56345 21 . B1PHWAT 40 3.8000 6.3000 4.6725 .46243 22 . B1PHCAL 40 3.5000 5.6000 4.1900 .44133 23. COARSE0/. 40 5.0000 95.000 46.625 23.949 24 . TEXTURE 40 3.OOOO 9.OOOO 4.7500 1.7209 25. B1C/.N 40 .80000 -1 .38000 .20700 .76902 26 .B1%C 40 2.4000 12.670 5.9607 2.5819 27. B1CNRAT 40 12.500 51.100 29.462 8.8890 28 , .B2PHWAT 36 4.3000 6.5000 5.0194 .40905 29. B2PHCAL 36 3.8000 5.6000 4.5389 .40162 30. .ORG%C 40 30. 100 53.300 45.826 5.4391 31 .ORGXN 40 .66000 1.6800 1.0892 .28331 32 .ORGCNRAT 40 23.500 74.500 44.655 11.825 274 Appendix 2 : Dry Pinus-Pseudotsuga f o r e s t s (Dl) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 3 60.000 322.00 215.67 137.79 2 .ASPECT 3 117.00 167.00 135.00 27.785 3 .SLOPE 3 10.OOO 60.OOO 31.667 25.658 4 .POSIT 3 1.0000 1.0000 1.0000 5 .DRAINAGE 3 1.OOOO 1.OOOO 1.OOOO 6 .EROOTDEP 3 3.OOOO 23.000 15.333 10.786 7 .ROOTDEP 3 3.OOOO 23.000 15.333 10.786 8 .SOILDEP 3 3.0000 23.000 15.333 10.786 9 .MATERIAL 3 0. 1.0000 .66667 .57735 10 .RATI01 3 1.0000 1.0000 1.0000 1 1 .RATI02 3 1.0000 1.0000 1.OOOO 12 .RATI03 3 .13000 1.OOOO .54333 .43662 13 .FIRE 3 1.0000 1.0000 1.0000 14 .WIND 3 0. 1.OOOO .66667 .57735 15 .WORMS 3 0. 0. 0. 16 .ORGPHWAT 3 4.OOOO 4.4000 4.2000 .200O0 17 . ORGPHCAL 3 3.3000 4.0000 3.7000 .36056 18 . ORGTHICK 3 3.0000 4.0000 3.3333 .57735 19. APHWAT 0 20. APHCAL 0 21 . B1PHWAT 2 4.8000 4.8000 4.8000 22. B1PHCAL 2 4.3000 4.3000 4.3000 23^ COARSE'/. 3 0. 95.000 58.OOO 50.863 24 . TEXTURE 2 6.0000 6.0000 6.0000 25 . B1%N 2 .20000 .28000 .24000 .56569 26. B1%C 2 3.1000 9.7500 6.4250 4.7023 27. B1CNRAT 2 15.300 34.900 25.100 13.859 28. B2PHWAT 0 29. B2PHCAL 0 30. ORG%C 3 36.150 47.840 43.030 6.1137 31 . ORG'/,fJ 3 .610O0 .880OO .74667 .13503 32. ORGCNRAT 3 48.200 78.400 59.300 16.614 Appendix 2 : Coastal dry Pinus f o r e s t s (D2) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 .ELEV 4 45.000 250.00 112.50 92.961 2 .ASPECT 4 46.000 129.00 80.500 35.369 3 .SLOPE 4 30.000 65.000 41.250 16.008 4 .POSIT 4 1.OOOO 1.0000 1.0000 5 .DRAINAGE 4 1.0000 1.0000 1.0000 6 .EROOTDEP 4 5.0000 20.000 11.000 7.3485 7 .ROOTDEP 4 5.OOOO 20.000 11.000 7.3485 8 .SOILDEP 4 5.0000 20.000 11.000 7 .3485 9 .MATERIAL 4 0. 0. 0. 10 .RATI01 4 1.OOOO 1.OOOO 1.OOOO 1 1 .RATI02 4 1.OOOO 1.0000 1.0000 12 .RATI03 4 .20000 1.0000 .41250 .39238 13 .FIRE 4 0. 0. 0. 14 . WIND 4 0. 1.OOOO .25000 .50000 15 .WORMS 4 0. , 0. 0. 16 .ORGPHWAT 4 3.8000 4.0000 3.9250 .95743 17 .ORGPHCAL 4 3.40O0 3.7000 3.5500 . 17321 18 .ORGTHICK 4 1.OOOO 14.000 5.2500 6.1305 19 .APHWAT 1 3.8000 3.8000 3.8000 20. . APHCAL 1 3.2000 3.2000 3.2000 21 .B1PHWAT 3 4.2000 5.4000 4.7333 .61101 22 . B1PHCAL 3 3.7000 4.7000 4.1O00 .52915 23. COARSE"/. 4 0. 75.000 27.500 33.292 24 . TEXTURE 3 2.0000 4.0000 3.0000 1 .OOOO 25 . E r/.N 3 .26000 .36000 .30667 .50332 26. ,B1°/.C 3 6.4000 15.620 9.5900 5.2251 27 . B1CNRAT 3 22.600 43.500 30.067 11.658 28. .B2PHWAT 0 29 .B2PHCAL 0 30 . 0RG7.C 4 40.800 49.760 46.180 3.8826 31 .0RG%N 4 .48000 .63000 .55250 .66018 32. .ORGCNRAT 4 70.300 1O0.10 84.800 15.227 Appendix 2 : Flo o d p l a i n f o r e s t s ( F l ) D E S C R I P T I V E MEASURES V A R I A B L E N MINIMUM MAXIMUM MEAN STD DEV 1 .ELEV 8 15 .000 95.OOO 5 4 . 3 7 5 3 9 . 6 8 1 2 ASPECT 8 O. 107.OO 24. 125 4 5 . 0 2 2 3. .SCOPE 8 0. 5 . 0 0 0 0 2 . 6 2 5 0 1 .9955 4 . P O S I T 8 5. OOOO 5.OOOO 5.OOOO 5. DRAINAGE 8 4 . OOOO 5.OOOO 4 . 3 7 5 0 .51755 6 . , EROOTDEP 8 1 1 .000 113.OO 5 8 . 1 2 5 3 1 . 8 0 9 7 . ROOTDEP 8 1 1 .000 1 3 0 . 0 0 7 6 . 6 2 5 4 3 . 9 4 8 8 . SDILDEP 8 62 .OOO 1 3 0 . 0 0 9 9 . 2 5 0 2 0 . 1 0 5 9. .MATERIAL 8 3. OOOO 4 . 0 0 0 0 3 . 3 7 5 0 . 5 1 7 5 5 10 . R A T I 0 1 8 . 6 1 0 0 0 1.0000 . 8 2 2 5 0 . 16369 1 1 .RAT 1 0 2 8 . 1 0 0 0 0 . 8 7 0 0 0 .57375 . 2 3 7 9 0 12 .RAT 1 0 3 8 . 3 0 0 0 0 -1 . 1 8 0 0 0 . 6 1 2 5 0 -1 .52491 13, F I R E 8 0. 1.OOOO .2 5 0 0 0 .46291 14 .WIND 8 0. 1.OOOO .5 0 0 0 0 .53452 15 .WORMS 8 1 . OOOO 3.OOOO 2 . 2 5 0 0 .88641 16 .ORGPHWAT 8 4 . 2 0 0 0 5 . 6 0 0 0 4 . 8 6 2 5 * .3 9 6 1 9 17 .ORGPHCAL 8 3 . 9 0 0 0 5 . 1 0 0 0 4 . 4 7 5 0 . 3 5 3 5 5 18 .ORGTHICK 8 1 . OOOO 10.OOO 3.OOOO 2. 8 7 8 5 19 ,APHWAT 6 4 . 4 0 0 0 5 . 7 0 0 0 5.1167 .42622 2 0 .APHCAL 6 3 . 9 OOO 5 . 4 0 0 0 4 . 6 5 0 0 .49699 21 .B1PHWAT 8 4 . 9 0 0 0 5.900O 5 . 3 6 2 5 .32486 22 .B1PHCAL 8 4 . 3 OOO 5 . 4 0 0 0 4 . 6 6 2 5 .35431 2 3 ,COARSE% 8 0. 1 0 . 0 0 0 1.2500 3 . 5 3 5 5 24 TEXTURE 8 3. OOOO 6 . 0 0 0 0 4 . 1 2 5 0 1 .5526 2 5 . B1%N 8 . 6 0 0 0 0 -1 . 3 0 0 0 0 . 19375 .83826 26. B1°/.C 8 1 . 0 2 0 0 7 . 1 2 0 0 3.8162 2 . 0 3 7 5 2 7 . B1CNRAT 8 17 . lOO 2 8 . 2 0 0 1 9 . 3 5 0 3 . 6 3 2 0 2 8 . . B2PHWAT 8 5. OOOO 6 . 1 0 0 0 5 . 4 6 2 5 .30677 2 9 . .B2PHCAL 8 4. 20O0 5 . 5 0 0 0 4 . 7 8 7 5 . 3 6 8 1 5 30, .ORG%C 8 25 . 2 1 0 4 9 . 2 0 0 3 8 . 4 9 0 7 . 7 2 5 6 31 . ORG'/»N 8 . 4 8 0 0 0 1.OOOO .68875 .16703 32. ,ORGCNRAT 8 34 .200 7 0 . 4 0 0 5 7 . 5 2 5 1 2 . 3 1 1 277 Appendix 2 : Floo d p l a i n f o r e s t s (Lysichitum variant) (F2) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 2 22.000 22.OOO 22.OOO 2 .ASPECT 2 0. 0. 0. 3 .SLOPE 2 0. 0. 0. 4 .POSIT 2 5.0000 5.0000 5.0000 5 .DRAINAGE 2 7.OOOO 7.0000 7.0000 6 .EROOTDEP 2 27.000 58.000 42.500 21.920 7 .ROOTDEP 2 27.000 85.000 56.000 41.012 8 .SOILDEP 2 82.000 85.000 83.500 2. 1213 9 .MATERIAL 2 4.0000 4.0000 4.0000 10 .RATI01 2 .68000 1.0000 .84000 .22627 11 .RATI02 2 .33000 .68000 .50500 .24749 12 .RATI03 2 .90000 -1 .19000 .14000 .70711 -1 13 .FIRE 2 0. 1.OOOO .50000 .70711 14 . WIND 2 0. 1.0000 .50000 .70711 15 .WORMS 2 O. 2.OOOO 1.OOOO 1 .4142 16 .ORGPHWAT 2 4.4000 4.6000 4.5000 .14142 17 .ORGPHCAL 2 4.0000 4.2000 4.1000 . 14 142 18 .ORGTHICK 2 5.OOOO 5.0000 5.OOOO 19 .APHWAT 2 4.OOOO 4.0000 4.0000 20 .APHCAL 2 3.6000 3.7000 3.6500 .707 1 1 -1 ,: 21 . B1PHWAT 2 4.3000 4.4000 4.3500 .70711 -1 :'• 22 . B1PHCAL 2 3.7000 3.8000 3.7500 .70711 -1 ; • 23. ,COARSE% 2 0. 0. 0. 24. TEXTURE 2 10.OOO 10.000 10.000 25. B 1%N 2 .26000 .27000 .26500 .70711 -2 26. Bf%C 2 4.4000 7.2000 5.8000 1.9799 27 . B1CNRAT 2 16.700 27.100 21.900 7.3539 28 . B2PHWAT 2 4.5000 4.7000 4.6000 . 14142 29. E2PHCAL 2 3.9000 4.OOOO 3.9500 .70711 -1 tv 30. ORG%C 2 37.200 40.400 38.800 2.2627 •*• 31 . ORG%N 2 .70000 .91000 .80500 . 14849 32 . ORGCNRAT 2 44.400 53.100 48.750 6. 1518 Appendix 2 : Dry Pseudotsuga f o r e s t s (PI) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 .ELEV 4 100.OO 325.OO 214.50 95.870 2 . ASPECT 4 32.000 149.00 110.25 53.984 3 .SLOPE 4 20.000 65.000 43.500 18.448 4 .POSIT 4 2.OOOO 3.OOOO 2.7500 .50000 5 .DRAINAGE 4 1.OOOO 3.0000 1.7500 .95743 6 .EROOTDEP 4 34.000 68.000 48.OOO 16.892 7 .ROOTDEP 4 34.OOO 68.000 54.250 14.431 8 .SOILDEP 4 34.000 68.000 54.250 14.431 9 .MATERIAL 4 1.OOOO 1.OOOO 1.OOOO 10 .RATI01 4 .58000 1.OOOO .83500 .210O0 11 .RATI02 4 .58000 1.0000 .89500 .21000 12 .RATI03 ' 4 .20000 -1 .12000 .80000 -1 .48990 13 .FIRE 4 1.OOOO 1.OOOO 1.0000 14 .WIND 4 0. 0.. 0. 15 .WORMS 4 0. 1.OOOO .25000 .50000 16 .ORGPHWAT 4 4.3000 4.6000 4.4000 . 14142 17 .ORGPHCAL 4 3.9000 4.2000 4.0250 . 12583 18 .ORGTHICK 4 1.OOOO 4.OOOO 3.2500 1.5000 19. .APHWAT 0 20. .APHCAL 0 21 . B1PHWAT 4 4.6000 5.1000 4.9000 .21602 22 . B1PHCAL 4 4.1000 4.6000 4.3500 .20817 23. COARSE!/. 4 41.000 85.000 69.OOO 19.253 24 . TEXTURE 4 3.0000 6.0000 4.2500 1.2583 25. B1%N 4 .10000 .22000 . 14750 .52520 26. B1%C 4 4.7000 11.700 7.7300 3.0746 27 . B1CNRAT 4 38.200 111.40 57.200 36.140 28. B2PHWAT 3 4.80OO 4.9000 4.8333 .57735 29. B2PHCAL 3 4.2000 4.4000 4.3000 .10000 30. ORG54C 4 33.320 44.500 40.030 4.7833 31 . ORG%N 4 .66000 .85000 .760O0 .89815 32. ORGCNRAT 4 46.900 63.500 53.050 7.7328 Appendix 2 : Pseudotsuga-Thuj a-Acer f o r e s t s (P2) , DESCRIPTIVE MEASURES ~ ' " ' ' VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 .ELEV 4 15.000 195.00 134.50 81.000 2 .ASPECT 4 14.000 162.00 118.50 69.979 3 .SLOPE 4 25.000 61 .000 43.250 14.975 4 .POSIT 4 3.0000 3.0000 3.OOOO 5 .DRAINAGE 2.0000 4.0000 2.7500 .95743 6 .EROOTDEP 4 29.000 84.000 55.750 25.591 7 .ROOTDEP 4 29.000 107.00 65.250 36.900 8 .SOILDEP 4 29.000 107.00 65.250 36.900 9 .MATERIAL 4 1.OOOO 1.OOOO 1.OOOO 10 .RATI01 4 .78000 1.0000 .90000 . 1 1662 1 1 .RATI02 4 .78000 i!oooo .90000 . 11662 12 .RATI03 4 .30000 -1 .80000 -1 .57500 -1 .26300 13 .FIRE 4 1.OOOO 1.OOOO 1.OOOO 14 .WIND 4 0. 0. 0. 15 .WORMS 4 0. 2.OOOO .5OOOO 1.0000 16 .ORGPHWAT 4 4.3000 5.1000 4.7750 .34034 17 . ORGPHCAL 4 4.OOOO 4.7000 4.3500 .28868 18 . ORGTHICK 4 1.0000 7.0000 3.5000 2.5166 19. ,APHWAT 1 5.2000 5.2000 5.2000 20. APHCAL 1 4.8000 4.8000 4.8000 2 1 . B1PHWAT 4 4.8000 5.6000 5.2250 .33040 22. B1PHCAL 4 4.3000 5.1000 4.6000 .34641 23. C0ARSE7. 4 20.OOO 90.000 62.500 32.275 24 . TEXTURE 4 1.OOOO 4.OOOO 3.2500 1.5COO 25. B1%N 4 .90000 -1 .15000 . 1 1750 .27538 26 . E1%C 4 2.6OOO 4.OOOO 3.360O .7 1536 27 . B1CNRAT 4 26.300 30.800 28.750 1.8520 28. B2PHWAT 3 4.9000 5.2000 5.0667 . 15275 29. B2PHCAL 3 4.3000 4.6000 4.4667 .15275 30. 0RG7.C 4 35.000 49.500 44.265 6.4213 31 . DRG%N ., 4 .60000 1.0100 .72750 .19259 32. ORGCNRAT 4 49.000 77.600 62.600 12.067 280 Appendix 2 : Pseudotsuga-Linnaea f o r e s t s (P3) , DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 rELEV 5 200.OO 590.00 324.00 157.26 2 . ASPECT 5 13.000 157.OO 80.400 67.859 3 .SLOPE 5 15.OOO 60.OOO 37.800 17.880 4 .POSIT 5 2.OOOO 3.0000 2.8000 .44721 5 .DRAINAGE 5 2.0000 4.OOOO 2.6000 .89443 6 . EROOTDEP 5 15.OOO 99.000 55.400 40.955 7 .ROOTDEP 5 15.000 99.000 59.600 40.698 8 .SOILDEP 5 15.OOO 125.00 64.800 47.997 9 .MATERIAL 5 1.OOOO 3.OOOO 1.4000 .89443 10 •RATI01 5 .68000 1.0000 .93600 . 1431 1 11 .RATI02 5 .68000 1.OOOO .89400 .15027 12 . RATI03 5 .50000.-1 .33000 .19000 .11979 13 . FIRE 5 1.OOOO 1.OOOO 1.0000 14 . WIND 5 0. O. 0. 15. .WORMS 5 0. 2.OOOO .60000 .89443 16 . ,ORGPHWAT 5 4.OOOO 5.7000 4.9000 .73824 17 . ORGPHCAL 5 3.50OO 5.4000 4.5400 .78294 18 . ORGTHICK 5 5.OOOO 11.OOO 6.8000 2.6833 19 . APHWAT 0 20. APHCAL 0 21 . B1PHWAT 5 4.6000 6.OOOO 5.2000 .68920 22 . B1PHCAL 5 4.1000 5.3000 4.6000 .51962 23. COARSE'/. 5 40.OOO 77.000 56.400 13.686 24 . TEXTURE 5 3.OOOO 4.0000 3.6000 .54772 25 . B1°/.N 5 .70000 -1 -20000 .15000 .54314 26. .B17.C 5 4.6000 14 .440 8.0220 3.8233 27 .B1CNRAT 5 30.40O 84.400 56.440 21.380 28 .B2PHWAT 3 4.9000 6.6000 5.8667 .87369 29 .B2PHCAL 3 4.3000 5.6000 5.1333 .72342 30 .ORG%C 5 35.630 49.880 43.402 6.4640 31 .ORG%N 5 .77000 1.2900 .95000 .20087 32 .ORGCNRAT 5 36.300 64.800 47.260 12.608 281 Appendix 2 : Pseudotsuga-Berberis f o r e s t s (P4) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 1 1 150.00 465.00 252.00 107.99 2 .ASPECT 11 37.000 173.00 108.27 51.219 3 .SLOPE 11 5.0000 60.000 40.909 18.987 4 POSIT 11 3.0000 4.0000 3. 1818 .40452 5 DRAINAGE 11 1.OOOO 3.0000 2.2727 .64667 6 EROOTDEP 11 26.000 117.00 67.455 29.784 7 ROOTDEP 11 29.000 117.00 78.364 27.332 8 SOILDEP 1 1 29.000 117.00 79.273 26.710 9 MATERIAL 11 1.0000 3.0000 1 .5455 .82020 10 RATI01 11 .31000 1.0000 .86909 .21925 1 1 RATI02 11 .31000 1.0000 .85545 .21491 12 RATI03 11 .30OO0 -1 .40000 . 15818 .11957 13 FIRE 1 1 0. 1.OOOO .90909 .30151 14 WIND 11 0. 0. 0. 15 WORMS 11 0. 2.0000 .63636 .92442 16 ORGPHWAT 1 1 3.6000 5.6000 4.1545 .62508 17 ORGPHCAL 1 1 3.300O 5.3000 3.7364 .63918 18 ORGTHICK 1 1 3.OOOO 23.000 8.6364 5.4639 19 APHWAT 2 3.9000 4.8000 4.3500 .63640 20 APHCAL 2 3.2000 4.OOOO 3.6000 . 56569 21 B1PHWAT 11 4.6000 5.4000 4 .9727 .26492 22 B1PHCAL 11 4.0000 4.8000 4.2909 .25082 23 COARSE"/. 11 50.000 84.000 71 .636 10.828 24 TEXTURE 11 2.OOOO 9.OOOO 3.8182 1.9400 25 B1%N 11 .40000 -1 .25000 .11636 .56617 -1 26 B 1%C 11 1.5600 6.7000 3.6164 1 .7445 27 B1CNRAT 11 18.000 77.300 33. 145 15.870 28 B2PHWAT 9 4.80O0 5.8000 5.1667 .36056 29..B2PHCAL 9 4.2000 5.0000 4.4778 .29059 30 ORG%C 11 27.010 51.800 44.104 7.5492 31 ORG"/.N 11 .54000 1.3200 .87273 .22055 32 ORGCNRAT 11 37.500 82.300 52.473 12.859 282 Appendix 2 : Tsuga-Pseudotsuga-Polystichum f o r e s t s (P5) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 17 70.OOO 500.OO 284.59 123.24 2 .ASPECT 17 0. 177.00 119.18 61.647 3 . SLOPE 17 4.OOOO 80.000 52.824 21.924 4 .POSIT 17 3.OOOO 5.0000 3.8235 .52859 5 .DRAINAGE 17 1.OOOO 4.OOOO 2.2941 .84887 6 .EROOTDEP 17 8.0000 128.00 60.94 1 37.64 1 7 ROOTDEP 17 61.OOO 128.00 89.471 22.867 8 .SOILDEP 17 61.OOO 164.00 100.59 28.483 9 .MATERIAL 17 1.OOOO 3.0000 1.2353 .66421 .10 .RATI01 17 .10000 1.OOOO .65529 . 28577 1 1 .RATI02 17 .60000 -1 1.OOOO .59941 .28137 12 .RATIOS 17 .6000O -1 1.OOOO .24353 .2227 1 13 .FIRE 17 0. 1.0000 .76471 .43724 14 .WIND 17 0. 0.. 0. 15 .WORMS 17 0. 2.0000 1 . 1 176 .92752 16 .ORGPHWAT 16 3.2000 4.8000 3.9687 .47570 17 .ORGPHCAL 16 2.7000 4.3000 3.4625 .47452 18 .ORGTHICK 17 5.OOOO 20.000 9.8824 3.77SO 19 .APHWAT 1 3.8000 3.8000 3.8000 20 .APHCAL 1 3.5000 3.5000 3.5000 21. .B1PHWAT 15 4.1000 6.OOOO 4.9733 .44476 22 .B1PHCAL 15 3.3000 5.4000 4.4200 .46782 23 .COARSE'/. 17 5.OOOO 100.00 64 . 1 18 30.116 24 .TEXTURE 15 1.0000 10.OOO 4.OOOO 2.6458 25 . B 1%N 15 .600O0 -1 .35000 .20067 .84386 - 1 26, ,Biy,c 15 2.2700 11.390 5.3353 2. 1659 27 . B1CNRAT 15 18.300 40.600 28.313 7.0625 28. . B2PHWAT 15 4.6000 6.2000 5.2933 .38999 29. . B2PHCAL 15 4.lOOO 5.7000 4.7600 .41884 30. .ORG%C 16 27.490 56.200 46. 123 6.6850 31 '.ORG%N 16 .76000 1.5600 1.0225 .21212 32. ORGCNRAT 16 32.000 60.000 46.162 8.4686 283 Appendix 2 : Montane Tsuga f o r e s t s (P6) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 12 102.00 795.OO 486.00 195.36 2 .ASPECT 12 27.000 177.00 116.67 50.869 3 .SLOPE 12 14.000 75.000 52.083 19.374 4 .POSIT 12 2.OOOO 4.OOOO 3.OOOO .42640 5 DRAINAGE 12 1 .OOOO 3.OOOO 2.4167 .66856 6 EROOTDEP 12 10.000 95.000 51.250 28.661 7 ROOTDEP 12 43.OOO 111.00 75.667 20.169 8 SOILDEP 12 43.000 120.00 85.583 26.919 9 MATERIAL 12 1.OOOO 2.OOOO 1.1667 .38925 10 RATI01 12 .15000 1.0000 .68083 .32520 1 1 RATI02 12 .11000 1.0000 .64833 .35022 12 RATIOS 12 .50000 -1 1.OOOO .31000 .34351 13 FIRE 12 0. 1.OOOO .91667 .28868 14 WIND 12 0. 0. 0. 15 WORMS 12 O. 3.OOOO 1.2500 1.1382 16 ORGPHWAT 12 3.5OOO 4.7000 3.8250 .37447 17 ORGPHCAL 12 2.9O00 4.1000 3.3333 .39158 18 ORGTHICK 12 4.OOOO 18.000 8.5000 4.1010 19 APHWAT 0 20 APHCAL 0 21 B1PHWAT 1 1 4.5000 5.1000 4.8182 .19400 22 B1PHCAL 1 1 4.0000 4.5000 4.2727 .17373 23 COARSE'/. 12 20.000 90.000 53.750 21.440 24 TEXTURE 1 1 2.OOOO 6.0000 3.5455 1.2933 25 B1%N 1 1 .50000 -1 .20000 .11818 .44004 26 B1%C 1 1 2.2400 7.1700 4.9145 1.6014 27 B1CNRAT 11 27.OOO 94.300 45.882 22.196 28 B2PHWAT 10 5.OOOO 5.4000 5.1500 .12693 29 B2PHCAL 10 4.3000 5.2000 4.6100 .25582 30 ORG%C 12 39.20O 50. 110 45.880 3.7412 31 ORG%N 12 .48000 1.1800 .77667 .19690 32 ORGCNRAT 12 37.500 104.40 63.025 18.709 > Appendix 2 : Montane Tsuga-Gaultheria f o r e s t s (P7) DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 .ELEV 7 220.00 805.OO 538.57 210.79 2 .ASPECT 7 31.000 178.OO 1 18.86 58.724 3 .SLOPE 7 10.000 70.000 39.286 26.011 4 .POSIT 7 1.OOOO 3.OOOO 2 . 1429 1.0690 5 .DRAINAGE 7 2.0000 4.0000 2.5714 .78680 6 .EROOTDEP 7 17.OOO 104.00 53.OOO 33.481 7 .ROOTDEP 7 32.000 105.00 79.143 27.492 6 .SOILOEP 7 32.OOO 105.OO 82 . 7 14 26.183 9 . MATERIAL 7 0. 3.OOOO 1.2857 .95119 10. .RATI01 7 .18000 1.OOOO .68000 .30589 11 . RATI02 7 .1800O 1.OOOO .66143 .32749 12 RATI03 7 .4OOOO -1 .6900O .29714 .26336 13 . FIRE 7 0. 1.0000 .57 143 .53452 14 . WIND 7 0. 1.OOOO .14286 .37796 15 . WORMS 7 O. 2.OOOO .85714 1.0690 16 . ORGPHWAT 7 3.400O 4.2000 3.8429 .35989 17 . ORGPHCAL 7 3.OOOO 3.8000 3.4000 .35590 18. ORGTHICK 7 4.0000 22.000 9.8571 6.7683 19 . APHWAT 3 3.8000 4.5000 4. 1333 .35119 20. APHCAL 3 3.2000 3.9000 3.5333 .351 19 21 . B1PHWAT 7 3.500O 5.2000 4.4571 .52870 22 . E1PHCAL 7 3.OOOO 4.5000 3.9143 .45251 23 . COARSE% 7 25.OOO 70.000 54.286 19.670 24 . TEXTURE 7 3.OOOO 6.0000 4.1429 1.3452 25. 817.N 7 .60000 - 1 .11000 .84286 -1 .15119 26. B 17.C 7 1.3000 4.9600 3.2714 1.1335 27. B1CNRAT 7 15.300 58.800 40.743 16.044 28. B2PHWAT 6 4.6000 5.100O 4.8833 .17224 29. B2PHCAL 6 4.20OO 4.80OO 4.3500 .23452 30. . 0RG7.C 7 42.370 55.700 46.823 4.7138 31 . 0RG7.N 7 .56000 .79000 .70429 .83438 32. .ORGCNRAT 7 59.600 83.000 67.014 7.9134 Appendix 2 : Coastal dry Thuja f o r e s t s (TI) ^DESCRIPTIVE MEASURES VARIABLE N MINIMUM MAXIMUM MEAN STD DEV 1 . ELEV 3 60.000 90.OOO 76.667 15.275 N 2 .ASPECT 3 59;000 137.OO 107.33 42.218 3 .SLOPE 3 40.OOO 54.000 46.333 7.0946 4 .POSIT 3 1.0000 3.0000 1.6667 1 . 1547 5 .DRAINAGE 3 1.OOOO 3.OOOO 1.6667 1 . 1547 6 .EROOTOEP 3 10.000 18.000 13.333 4. 1633 7 .ROOTDEP 3 . 10. OOO 27.000 16.333 9.2916 8 .SOILDEP 3 10.000 27.000 16.333 9.2916 9 .MATERIAL 3 0. 2.0000 .66667 1.1547 10 .RATI01 3 .67000 1.0000 .89000 .19053 11 .RATI02 3 .67000 1.0000 .89000 .19053 12 .RATI03 3 .17000 1.0000 .72333 .47920 13 . FIRE 3 0. 0. 0. 14 . WIND 3 1.OOOO 1.OOOO 1.OOOO 15 .WORMS 3 0. 2.0000 1.0000 1.OOOO 16 .ORGPHWAT 3 4.1000 4.5000 4.3000 .20000 17 .ORGPHCAL 3 3.80O0 4.1O00 3.