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Plant associations of the Cariboo - Aspen - Lodgepole pine - Douglas-Fir parkland zone Beil, Charles Edward 1969

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THE PLANT ASSOCIATIONS OF THE CARIBOO - ASPEN LODGEPOLE PINE - DOUGLAS-FIR PARKLAND ZONE - by CHARLES EDWARD BEIL B.Sc, University of Alberta, 1963 M.'Sc, University of Alberta, 1966 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of ' '•' Botany We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA December, 1969 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced d e g r e e a t the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and S t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department or by h i s r e p r e s e n t a t i v e s . It i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s thes . is f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f B O T A N Y  The U n i v e r s i t y o f B r i t i s h Co lumbia V a n c o u v e r 8, Canada Date December i s 1 9 6 9 ABSTRACT The o b j e c t i v e s of t h i s study were to obtain q u a n t i t a t i v e and q u a l i t a t i v e data on the vegetation and environmental factors of the Cariboo Zone and to synthesize these data i n t o an ecosystematic c l a s s i f i c a t i o n . Sample p l o t s were chosen s e l e c t i v e l y according to c r i t e r i a based on uniformity and discreteness. Vegetation was studied using the phyto-s o c i o l o g i c a l methods of the Ziirich-Montpellier School. On a l l p l o t s data were also obtained f o r edaphic and physiographic f a c t o r s . Based on f l o r i s t i c composition and environmental data the 131 p l o t s were synthesized i n t o a f l e x i b l e ecosystematic c l a s s i f i c a t i o n i n which eight orders, twelve a l l i a n c e s , twenty associations and s i x subassociations were described. The order Pseudotsugetalia menziesii with three associations dominated most of the forested areas, occurring on subhygric to subxeric h a b i t a t s . The order P i c e e t a l i a glaucae with three associations occurred only marginally; always on subhygric to subhydric h a b i t a t s . The order Koelerio -Agropyretalia s p i c a t i with eight associations dominated the grassland areas, occurring on f i n e textured s o i l s of aeolian o r i g i n . The order P u c c i n e l l i e t a l i a a i r o i d i s with two associations dominated the s a l i n e - a l k a l i n e h a b i t a t s . The orders B e t u l e t a l i a glandulosae, S a l i c e t a l i a , S c i r p e t a l i a v a l i d i , and C a r i c e t a l i a rostratae were represented by s i n g l e associations of r e s t r i c t e d d i s t r i b u t i o n s . S o i l s representative of a l l s i x orders of the Canadian S o i l C l a s s i f i c a t i o n system were d i s t i n g u i s h e d with Chernozemic and B r u n i z o l i c s o i l s the most common. Melanization appeared to be the dominant soi l - f o r m i n g process and the s o i l s were generally r i c h having high cation exchange c a p a c i t i e s , high amounts of exchangeable cations and a l k a l i n e r e a c t i o n s . An examination of the population structures of the major tree species showed that Pseudotsuga menziesii had the widest amplitude and formed the climax forest cover over much of the Cariboo Zone. Picea glauca had a narrower amplitude and Pinus contorta and Populus tremuloides reached dominance only as pioneer species. Selected ecosystem units were characterized microclimatically. The Agropyrion spicati occupied microclimatically warm areas while the f l o r i s t i c a l l y related Stipion columbianae was present in areas with a cool microclimate. The Antennario - Poetum secundae and Stipetum richardsonii, although bordering associations, occupied microclimately distinct habitats. Forest communities were shown to develop at higher elevations where a cool microclimate prevails. Based on species significance data, plots were objectively grouped by the weighted-pair-group and the weighted-variable-group methods of cluster analysis. The resulting hierarchical arrangements of plots paralleled very closely the subjectively derived ecosystematic cl a s s i f i c a t i o n . On the dendro-gram obtained by the weighted-variable-group method, associations were distinguished and their degree of homogeniety and ecological relationships were demonstrated. The forest-grassland boundary in the Cariboo Zone was assessed to be relatively stable and to be controlled by available s o i l moisture as related to s o i l texture. It was apparent though, that minor fluctuations in the boundary as a result of grazing and f i r e occur. Detailed topographic relationships of the associations were demonstrated and i t was apparent that topography, which represents a complex of physio-graphic factors, i s important in controlling the distribution of associations. Successional changes appeared to be operating at a slow rate and i i thus most of the associations described were in a stable condition. The Agropyretum spicati most closely approximated the climatic climax association, occurring on ridges and slopes. Other stable associations were rated as edaphic or topographic climaxes. The successional relationships of the associations were demonstrated within a monoclimax concept in which i t was assumed that ultimately a l l associations would change into the climax as a result of s o i l weathering and peneplanation of the land. It was concluded that the gynecological approach and cla s s i f i c a t i o n methods used allowed the presentation of data in an ecosystematic format which could be directly applied to range or forest management but could also serve as a basis for more detailed s c i e n t i f i c studies. i i i TABLE OF CONTENTS Page I INTRODUCTION 1 II CONCEPT AND APPROACH 5 III REGIONAL DESCRIPTION 8 Area of Study Defined 8 Physiography 8 Soils 11 Climate 12 IV THE ECOSYSTEM UNITS 15 Methods of Analysis 15 Plant Identification and Nomenclature 17 Soil Sampling and Analyses 18 Vegetation Synthesis and Classification 20 Description of the Plant Associations (by Order and Alliance) 21 Caricetalia rostratae Caricion rostratae Caricetum rostratae 23 Salicetalia Salicion monticolae Carico (rostratae) - Salicetum monticolae 32 Scirpetalia v a l i d i Scirpion v a l i d i Scirpetum v a l i d i 41 Puccinellietalia airoidis Distichlion strictae 48 1. Puccinellio (airoidis) - Hordeetum jubati 48 2. Distichlo (strictae) - Spartinetum g r a c i l i s 57 iv TABLE OF CONTENTS (Continued) Page Betuletalia glandulosae Muhlenbergio (richardsonis)- Betulion glandulosae Muhlenbergio (richardsonis) - Betuletum glandulosae 66 Koelerio (gracilis) - Agropyretalia spicati 74 Stipion columbianae 1. Poo (juncifoliae) - Elymetum cinerei 76 2. Antennario (dimorphae) - Poetum secundae 86 (1) antennario (dimorphae)-poetosum secundae 95 (2) juncetosum b a l t i c i 96 3. Agropyro (spicati) - Balsamorhizetum sagittatae 97 4. Stipetum richardsonii 107 Agropyrion spicati 1. Agropyretum spicati 115 2. Agropyro (spicati) - Artemisietum tridentatae 125 3. Opuntio (fragilis) - Stipetum comatae 133 4. Agropyro (spicati) - Juniperetum scopulorum 143 Pseudotsugetalia menziesii 150 Arctostaphylo (uva-ursi) - Pseudotsugion *glaucae Arctostaphylo (uva-ursi) - Junipero (communis) -Pseudotsugetum *glaucae 151 Calamagrostido (rubescentis) - Pseudotsugion *glaucae 1. Calamagrostido (rubescentis) - Pseudotsugetum *glaucae 162 (1) calamagrostido (rubescentis) - pseudotsugetosum *glaucae 171 (2) pinetosum contortae 173 v TABLE OF CONTENTS (Continued) Page 2. Rhytidiadelpho (triquetri) - Pleurozio (shreberi) - Pseudotsugetum *glaucae 176 Piceetalia glaucae 186 Poo (interioris) - Calamagrostido (rubescentis) -Populion tremuloidis Poo (interioris) - Calamagrostido (rubescentis) -Populetum tremuloidis 189 (1) poo (interioris) - calamagrostido (rubescentis)-populetosum tremuloidis 195 (2) lonicero (involucratae) - caricetosum leptopodae 200 Carico (concinnae) - Piceion glaucae Carico (concinnae) - Piceetum glaucae 203 Equiseto (arvensis) - Piceion glaucae Equiseto(arvensis) - Piceetum glaucae 213 V POPULATION STRUCTURES OF THE MAJOR TREE SPECIES OF THE CARIBOO ZONE 224 Methods of Analysis and Synthesis 224 Growth and Population Size of the Tree Species 224 Population Dynamics of the Tree Species 230 VI MICROCLIMATE 238 Methods of Analysis and Synthesis 238 Comparison of Selected Associations Based on Microclimate 240 VII CLUSTER ANALYSES 249 Methods of Synthesis 249 Comparison of the Weighted-Pair-Group and the Weighted-Variable-Group Methods of Cluster Analysis 252 v i TABLE OF CONTENTS (Continued) Relationship of Ecosystem Units on the Dendrogram Obtained by the Weighted-Variable-Group Method of Cluster Analysis RELATIONSHIP BETWEEN FOREST AND GRASSLAND VEGETATION ECOLOGICAL RELATIONSHIPS OF THE ASSOCIATIONS Spatial Relationships Topographic Sequence of Forest Associations Present in the Area North of Williams Lake Topographic Sequence of the Associations Present in the Major Valleys of the Fraser Plateau Topographic Sequence of the Associations Present in Upland Areas of the Fraser Plateau Topographic Sequence of the Associations of Saline-Alkaline Habitats Topographic Sequence of the Associations formed in Glacial Stream Depressions Successional Relationships Successional Relationships of Associations Formed Primarily on Aeolian Deposits or Aeolian Deposits over Glacial Drif t . Successional Relationships of Associations Formed Primarily on Glacial D r i f t Successional Relationships of Associations Formed Primarily on Alluvium Successional Relationships of Associations Formed on Sediments in Lakes without Drainage Successional Relationships of Associations Formed on Sediments in Drained Lakes and Connecting Channels SUMMARY AND CONCLUSIONS v i i TABLE OF CONTENTS (Continued) Page XI BIBLIOGRAPHY 312 XII APPENDICES 321 v i i i LIST OF TABLES Table Page 1. Temperature and Precipitation Summaries for Big Creek and Williams Lake, British Columbia 13 2. Hierarchical Arrangement of the Ecosystem Units Described for the Cariboo Zone 22 3. Caricetum rostratae Environment Data 24 4. Caricetum rostratae Vegetation Data 25 5. Caricetum rostratae Soil Texture 28 6. Caricetum rostratae Soil Chemical Analysis 29 7. Carico - Salicetum monticolae Environment Data 33 8. Carico - Salicetum monticolae Vegetation Data 34 9» Carico - Salicetum monticolae Soil Texture 36 10. Carico - Salicetum monticolae Soil Chemical Analysis 37 11. Scirpetum v a l i d i Environment Data 42 12. Scirpetum v a l i d i Vegetation Data 43 13. Scirpetum v a l i d i Soil Texture 45 14. Scirpetum v a l i d i Soil Chemical Analysis 46 15o Puccinellio - Hordeetum jubati Environment Data 50 16. Puccinellio - Hordeetum jubati Vegetation Data 51 17. Puccinellio - Hordeetum jubati Soil Texture 53 18. Puccinellio - Hordeetum jubati Soil Chemical Analysis 54 19. Distichlo - Spartinetum g r a c i l i s Environment Data 58 20. Distichlo - Spartinetum g r a c i l i s Vegetation Data 59 ix LIST OF TABLES (Continued) Table Page 21. Distichlo - Spartinetum g r a c i l i s Soil Texture 62 22. Distichlo - Spartinetum g r a c i l i s Soil Chemical Analysis 63 23. Muhlenbergio - Betuletum glandulosae Environment Data 67 24. Muhlenbergio - Betuletum glandulosae Vegetation Data 68 25. Muhlenbergio - Betuletum glandulosae Soil Texture 71 26. Muhlenbergio - Betuletum glandulosae So i l Chemical Analysis 72 27. Poo - Elymetum cinerei Environment Data 79 28. Poo - Elymetum cinerei Vegetation Data 80 29. Poo - Elymetum cinerei Soil Texture 82 30. Poo - Elymetum cinerei Soil Chemical Analysis 83 31. Antennario - Poetum secundae Environment Data 87 32. Antennario - Poetum secundae Vegetation Data 88 33. Antennario - Poetum secundae Soil Texture 90 34. Antennario - Poetum secundae Soil Chemical Analysis 91 35. Agropyro - Balsamorhizetum sagittatae Environment Data 99 36. Agropyro - Balsamorhizetum sagittatae Vegetation Data 100 37. Agropyro - Balsamorhizetum sagittatae Soil Texture 102 38. Agropyro - Balsamorhizetum sagittatae Soil Chemical Analysis 103 39. Stipetum richardsonii Environment Data 108 40. Stipetum richardsonii Vegetation Data 41. Stipetum richardsonii Soil Texture 42. Stipetum richardsonii Soil Chemical Analysis 43. Agropyretum spicati Environment Data 117 x LIST OF TABLES (Continued) Table Page 44. Agropyretum spicati Vegetation Data 118 45. Agropyretum spicati Soil Texture 120 46. Agropyretum spicati Soil Chemical Analysis 121 47. Agropyro - Artemisietum tridentatae Environment Data 126 48. Agropyro - Artemisietum tridentatae Vegetation Data 127 49. Agropyro - Artemisietum tridentatae Soil Texture 130 50. Agropyro - Artemisietum tridentatae Soil Chemical Analysis 131 51. Opuntio - Stipetum comatae Environment Data 135 52. Opuntio - Stipetum comatae Vegetation Data 136 53. Opuntio - Stipetum comatae Soil Texture 138 54. Opuntio - Stipetum comatae Soil Chemical Analysis 139 55. Agropyro - Juniperetum scopulorum Environment Data 144 56. Agropyro - Juniperetum scopulorum Vegetation Data 145 57. Agropyro - Juniperetum scopulorum Soil Texture 147 58. Agropyro - Juniperetum scopulorum Soil Chemical Analysis 148 59. Arctostaphylo - Junipero - Pseudotsugetum *glaucae Environment Data 153 60. Arctostaphylo - Junipero - Pseudotsugetum *glaucae Vegetation Data 154 61. Arctostaphylo - Junipero - Pseudotsugetum *glaucae Soil Texture 156 62. Arctostaphylo - Junipero - Pseudotsugetum *glaucae Soil Chemical Analysis 157 63. Calamagrostido - Pseudotsugetum *glaucae Environment Data 163 64. calamagrostido - Pseudotsugetum *glaucae Vegetation Data 164 x i LIST OF TABLES (Continued) Table Page 65. Calamagrostido - Pseudotsugetum *glaucae Soil Texture 167 66. Calamagrostido - Pseudotsugetum *glaucae Soil Chemical Analysis 168 67. Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae Environment Data 178 68. Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae Vegetation Data 179 69. Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae Soi l Texture 181 70. Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae Soil Chemical Analysis 182 71. Poo - Calamagrostido - Populetum tremuloidis Environment Data 190 72. Poo - Calamagrostido - Populetum tremuloidis Vegetation Data 191 73. Poo - Calamagrostido - Populetum tremuloidis S o i l Texture 193 74. Poo - Calamagrostido - Populetum tremuloidis So i l Chemical Analysis 194 75. Carico - Piceetum glaucae Environment Data 205 76. Carico - Piceetum glaucae Vegetation Data 206 77. Carico - Piceetum glaucae Soil Texture 208 78. Carico - Piceetum glaucae Soil Chemical Analysis 209 79. Equiseto - Piceetum glaucae Environment Data 215 80. Equiseto - Piceetum glaucae Vegetation Data 216 81. Equiseto - Piceetum glaucae Soil Texture 218 82. Equiseto - Piceetum glaucae Soil Chemical Analysis 219 83. Summary Synthesis Table for the Ecosystem Units of of the Cariboo Zone 223 x i i LIST OF TABLES (Continued) Table Page 84. The Density of Pseudotsuga menziesii, Picea glauca, Pinus contorta and Populus tremuloides by Height Class Expressed as the Number of Stems per Acre Together with Height, Age and Diameter Measurements 231 85. Location of Microclimatic Stations 239 86. Summary of Snow-Cover Data for the Antennario - Poetum secundae and the Stipetum richardsonii 247 x i i i LIST OF FIGURES Figure Page 1. The Chilcotin River Valley 9 2. The Upland Region of the Fraser Plateau 9 3. The Caricetum rostratae 31 4. The Carico - Salicetum monticolae 31 5. The Scirpetum v a l i d i 40 6. The Puccinellio - Hordeetum jubati 56 7. The Distichlo - Spartinetum g r a c i l i s 56 8. The Muhlenbergio - Betuletum glandulosae 65 9. The Poo - Elymetum cinerei 77 10. The Antennario - Poetum secundae antennario -poetosum secundae 94 11. A Close-up View of the Antennario - Poetum secundae juncetosum b a l t i c i 94 12. The Agropyro - Balsamorhizetum sagittatae 106 13. The Stipetum richardsonii 106 14. The Agropyretum spicati 124 15. The Agropyro - Artemisietum tridentatae 124 16. The Opuntio - Stipetum comatae 142 17. The Agropyro - Juniperetum scopulorum 142 18. The Arctostaphylo - Junipero - Pseudotsugetum *glaucae 161 19. The Calamagrostido - Pseudotsugetum *glaucae calamagrostido - pseudotsugetosum *glaucae 161 20. The Calamagrostido - Pseudotsugetum *glaucae pinetosum contortae 174 xiv LIST OF FIGURES (Continued) Figure Page 21. The Calamagrostido - Pseudotsugetum *glaucae pinetosum contortae with an Understory Layer of Pseudotsuga menziesii 174 22. The Rhytidiadelpho - Pleurozio — Pseudotsugetum *glaucae 185 23. The Pleurozio - Vaccinio - Piceetum glaucae 185 24. The Poo - Calamagrostido - Populetum tremuloidis poo - calamagrostido - populetosum tremuloidis 199 25. The Poo - Calamagrostido - Populetum tremuloidis lonicero - caricetosum leptopodae 199 26. The Carico - Piceetum glaucae 212 27. The Equiseto - Piceetum glaucae 212 28. Basal Area Estimates in Square Feet per Acre for Pseudotsuga menziesii, Picea glauca, Pinus contorta and Populus tremuloides by Height Class for Associations of Occurrence 225 29. Maximum, Average Maximum, Average Minimum and Minimum Monthly Temperatures Recorded at the Microclimatic Stations for the Months of May, June, July, August and September (1968) 241 30. Dendrogram of the 131 Plots Obtained by the Weighted-Pair-Group Method of Cluster Analysis 253 31. Dendrogram of the 131 Plots Obtained by the Weighted-.Variable-Group Method of Cluster Analysis 254 32. A Soil Profile Characteristic of Grassland Areas 262 33. Topographic Sequence of Forest Associations Developed on Sandy Outwash Deposits 268 34. Topographic Sequence of Forest Associations Developed on Glacial Drif t (with a clay matrix) 270 35. Topographic Sequence of the Associations Present i n the Major Valleys of the Fraser Plateau 272 xv LIST OF FIGURES (Continued) Figure Page 36. A Deep Water-Cut Ravine in the Chilcotin Valley 274 37. Topographic Relationship Between the Opuntio -Stipetum comatae and the Agropyretum spicati 276 38. An Illustration of the Effect of Exposure on the Development of Associations in the Chilcotin Valley 276 39. Topographic Sequence of the Associations Present in the Upland Areas of the Fraser Plateau 278 40. Topographic Relationships of the Calamagrostido -Pseudotsugetum *glaucae, the Stipetum richardsonii and the Antennario - Poetum secundae 280 41. Topographic Sequence of the Associations Present i n Saline-Alkaline Habitats 282 42. Topographic Sequence of Associations Formed in Glacial Stream Depressions and their Relationship to Associations of Upland Habitats 284 43. Proposed Successional Relationships of the Associations and Subassociations of the Cariboo Zone 288 xvi LIST OF APPENDICES Appendix I II III IV Table IV-A IV-B Scales used for Estimating Species Significance and Sociability Checklist of Plants Explanatory Notes for Vegetation, Environment and So i l Tables Summary of the Temperature Data for the Microclimatic Stations Weekly Temperature Summaries for the Microclimatic Stations Monthly Temperature Summaries for the Microclimatic Stations Page 322 323 332 338 339 342 x v i i ACKNOWLEDGEMENTS The writer wishes to thank Dr. V. J. Krajina for suggesting the topic of investigation and for his guidance, assistance and encouragement during a l l phases of this study. Thanks are also due to Dr. C. D. Bird for identifying the lichen collections; to Mr. Frank Boas for identifying the bryophyte collections; to Dr. V. Bednar for identifying the Carex collection and for help with the vegetation synthesis; to Mr. M. K. Wali for aid with the chemical analyses of the soils and also for many helpful suggestions and discussions; to Mr. B. von Spindler for performing certain chemical analyses on the so i l s ; to Dr. W. B. Schofield and Dr. G. E. Rouse for suggestions on the preparation of this thesis; to Mr. D. I. Grant, Mr. B. T. Koshman and Mr. Rod Watt for assistance i n the f i e l d and to the Department of Botany for supplying space and equipment. Special thanks are due to "the Watts of Big Creek" who gave the writer food, shelter and companionship during the f i e l d portion of this study. This study was supported in part by a National Research Council Post Graduate Scholarship awarded to the author and by a National Research Council operating grant (No. A-92) awarded to Dr. V. J. Krajina, both of which are gratefully acknowledged. x v i i i I INTRODUCTION The natural vegetation of British Columbia has, to date, been l i t t l e studied. Several authors have, however, made general vegetation classifications. Whitford and Craig (1918) divided the province into forest types. Halliday (1937), using a regional approach in his Forest Types of Canada, divided B r i t i s h Columbia into seven regions. Later Rowe (1959) provided a similar division of the province. These studies were based primarily on forest vegetation and climate. Krajina (1965) provided a more detailed division of British Columbia, based on vegetation, climate and s o i l s . He divided the province into seven biogeoclimatic regions and eleven biogeoclimatic zones. Forest as well as non-forest vegetation was considered i n this division. A detailed characterization of these zones based on the ecological function of forest trees i s given by Krajina (1969) . Within this zonal framework a series of ecological investigations on the vegetation of British Columbia i s in progress. The present study i s part of this and i s concerned with the Cariboo - Aspen - Lodgepole Pine -Douglas-fir Parkland Zone. For convenience, in this dissertation the name of the Zone has been shortened to, simply, Cariboo Zone. The Cariboo Zone, i s part of the Canadian Cordilleran Forest Region (Krajina 1965) and has a dry continental subhumid climate. The Zone is located i n the rain shadow area east of the Coast Mountains and for the most part i s forested but also contains areas of native grassland. The present study was concentrated in the southern part of the Cariboo Zone. Previous studies of vegetation which make reference to this area 2 are relatively few. Dawson (1876) in his report on geological explorations in British Columbia mentioned that the forests along the Fraser River occur at relatively high elevations and are dominated by Pseudotsuga menziesii and Pinus contorta. He further stated that the benches along the major rivers are warmer, open prairie like and clothed with bunch-grass in which Artemisia spp. and cactus occur. Whitford and Craig (1918) referred to the area as being mostly forested by Pseudotsuga menziesii with Pinus contorta present extensively as a result of f i r e s . They mentioned an Artemisia tridentata (sage brush) type to be present along the Fraser and Chilcotin Rivers which is bordered by an open grassland, dominated by Agropyron spicatum, that extends up to meet the forest. Ilvessalo and Kujala, two Finnish foresters, c l a s s i f i e d Canadian forests based on understory vegetation. The Arctostaphylos, Calamagrostis -Arctostaphylos and Calamagrostis types described by Ilvessalo (1929) correspond to forest communities of the Cariboo Zone. Similarly, Kujala (1945) in a more comprehensive work described a "semi-arid interior region" which encompasses most of the Cariboo Zone. He also recognized an Arctostaphylos type, an Arctostaphylos - Calamagrostis type and a Calamagrostis type. These types were present under canopies of Pseudotsuga menziesii or Pinus contorta. Neither of these Finnish authors referred to the more arid treeless vegetation, common i n the area. Tisdale (1947) made an ecological study of the grasslands of the southern interior of British Columbia which included part of the present study area. He recognized three grassland zones, located at successively higher elevations, and a l l dominated by Agropyron spicatum. He described a number of associations (Clements 1936) within each zone and paid particular attention to retrogressive changes which take place as a result of grazing. 3 McLean and Marchand (1964), classified the grasslands of the area into condition classes with reference to the degree of grazing. The s o i l s and climate of the grasslands of B r i t i s h Columbia were br i e f l y discussed by van Ryswyk et a l . (1965), based largely on the work of Tisdale. Illingworth and Arlidge (1960) described some lodgepole pine forest s i t e types from the interior of Br i t i s h Columbia; their Calamagrostis and Calamagrostis - Arctostaphylos site types are represented i n the study area. Hamet-Ahti (1965) in a brief description of vegetation zones of British Columbia placed the region along the lower Fraser River, encompassing the present study area, i n her Hemiboreal Zone. She did not make any detailed investigation i n this area and mentioned only that pseudotsuga menziesii i s the dominant species. South of the study area, Brayshaw (1955, 1965) described associations of the Bunch Grass - Ponderosa Pine Zone, many of which are similar to communities of the Cariboo Zone. Further to the south, in eastern Washington and adjacent Idaho, Daubenmire (1942, 1952) has described associations from steppe and forest vegetations. In the grassland regions of Washington, Daubenmire (1942) recognized the same three zones that Tisdale later recognized for Br i t i s h Columbia. In dealing with the forest areas Daubenmire (1952) distinguished four zones of which the Pseudotsuga menziesii zone shows a close similarity to the forested parts of the Cariboo. It i s apparent from this brief literature review that previous to the present study the Cariboo Zone has been ecologically poorly documented. This investigation on the vegetation and environment of the Cariboo Zone was i n i t i a t e d in 1967 and continued through 1968. The main objectives were: 4 (1) to obtain q u a n t i t a t i v e and q u a l i t a t i v e data on e x i s t i n g vegetation; (2) to obtain s i m i l a r data on the p h y s i c a l environment with p a r t i c u l a r emphasis on physiographic and edaphic f a c t o r s ; and (3) to present these data i n the form of a f l e x i b l e c l a s s i f i c a t i o n of recognizable ecosystem u n i t s . From such a c l a s s i f i c a t i o n s p a t i a l as w e l l as successional r e l a t i o n -ships of ecosystem units can be i n t e r p r e t e d . D e tailed a u t e c o l o g i c a l information was not obtained i n t h i s study. However, the autecology, of at l e a s t the dominants, can be i n f e r r e d from the ecosystematic data provided. A l l previous studies which have dea l t with t h i s area have been concerned e i t h e r with f o r e s t or with grassland; none have attempted to deal with both vegetation types i n d e t a i l . The present study includes d e s c r i p t i o n s of both types as w e l l as data on t h e i r e c o l o g i c a l r e l a t i o n s h i p s . Thus i t i s b elieved that the information obtained could be u s e f u l as an a i d i n land management o f t h i s economically important region. 5 II CONCEPT AND APPROACH In current plant ecology there exist two concepts on the nature of vegetation, namely the continuum concept and the community concept. Proponents of the continuum adhere to the idea that vegetation varies continually in space and time and that recognizable vegetation units do not exist. The continuum concept has recently been reviewed in detail by Mcintosh (1967). Adherents of the community concept believe that vegetation i s composed of a mosaic of homogeneous vegetation units (plant communities), which occur repetitively, as recognizable entities i n similar habitats i n any area with a similar vegetation history. A review of the literature dealing with communities and their classification has been made by Whittaker (1962). A possible third concept on the nature of vegetation i s available from an amalgamation of these two as put forward by Poore (1955, 1956, 1964). Here, vegetation i s regarded to be continuous but to contain distinct and repetitive reference points or "noda". Noda are formed by abstraction from large numbers of similar stands and thus approximate the associations of phytosociology. This nodal concept of vegetation has been adopted i n the present study. The basic unit of study i n this dissertation i s the plant associa-tion as proposed at the Third International Botanical Congress of 1910 (according to Braun-Blanquet 1932) and modified by Krajina (1960) to include environment. It i s by definition considered to be ecosystematic. The association i s formed by abstraction from sampled communities which are vegetationally and environmentally homogeneous. The association as used here i s comparable to the biogeocoenosis type of Sukachev (1944, 1945) 6 and the ecosystem of Tansley (1935) while the individual plant communities (plots) are comparable to the biogeocoensis of Sukachev (1944, 1945) and Krajina (1965, 1969). A system of selective sampling was employed in this study in preference to a random or systematic scheme (Greig-Smith 1964). By this technique the infrequently occurring communities as well as the commonly occurring ones are adequately sampled and thus a more complete description of the area i s possible. If, on the other hand, a random sampling scheme had been used, the common communities would be sampled more often than the rare ones and a great many more samples would be required to provide the same descriptions. Recently there has been a trend in ecology to replace subjective methods of vegetation analysis with objective more quantitative ones. Although objective methods may yie l d an increase in accuracy they are time consuming to use. In view of this fact traditional phytosociological subjective methods of analyses have been used in this study. It i s believed that any loss in accuracy which may be inherent in the methods i s compensated for by their rapidity; thus allowing more communities to be studied. Transitional communities were not sampled in this work, instead emphasis was placed on the description of the vegetation noda. This provides a clearly defined ecological framework of plant associations. It i s believed that most transitional communities occurring in the Cariboo Zone can be placed with accuracy into this framework. In a general synecological study, such as this, i t i s not possible, nor practical to measure in detail a l l the factors operating in a holocoenotic environment (Billings 1952). Therefore some of the information presented in the association descriptions i s only observational being inferred from measured 7 factors or landscape position of the sampled communities. The inclusion of such data may be c r i t i c i z e d , and perhaps justly so. However, i t i s reasoned that i f careful thought and understanding accompanies such observations and inferences, the data, although subjective, are of value. Hopefully, the inclusion of these data w i l l make the ecology of this zone more meaningful and understandable. Certainly by discussing a l l the seemingly important factors and not simply the quantitatively measured ones, this study w i l l be of more use as a basis for detailed autecological studies and management practices. In general the approach used i n this study i s regarded to be ecosystematic. Traditional phytosociological methods are coupled with detailed environmental measurements to f a c i l i t a t e the descriptions of the associations. 8 III REGIONAL DESCRIPTION Area of Study Defined The area covered by this study i s the Southern Subzone of the Cariboo - Aspen - Lodgepole Pine - Douglas-fir Parkland Zone (Krajina 1965, 1969). Geographically the study area i s divided into two parts. One part extended from Williams Lake (52°10' N - 122°05'W) north to McAllister (52°27', 122°23*). The other part was centred in the Chilcotin region and extended from Riske Creek (51°57'N - 122°32'W) southwest to Big Creek (51°44' N, 123°02'W) and southeast to the Gang Ranch (51°33,N, 122°22'W). The area north of Williams Lake i s predominantly forested with Pseudotsuga menziesii as the dominant species. The Chilcotin region, on the other hand, i s largely an area of grassland with forested h i l l s and valleys (Fig. 1 and 2). Agropyron spicatum i s the dominant grass and the forests are mostly composed of Pseudotsuga menziesii, Pinus contorta and Populus tremuloides. Phytogeographically, this area l i e s north of the distributional limits of Pinus ponderosa, as defined by Brayshaw (1955). It i s south of the distributional limits of Picea mariana, and Picea glauca i s only marginally represented. The forested areas show greatest similarity to the Douglas-fir Biogeoclimatic Zone (Krajina 1965). The grassland areas of the Chilcotin valley are very similar to those to the south in the Thompson and Nicola valleys as described by Tisdale (1947). Physiography The area studied forms the central portion of the physiographic region designated as the Interior Plateau which has a length of 560 miles and a maximum width of 235 miles (Holland 1964). The Plateau i s flanked by the Coast and Cascade Mountains on the west and by the Rocky Mountains and Columbia 9 F i g . 1. The C h i l c o t i n River v a l l e y showing the r e l a t i o n s h i p between grassland and f o r e s t vegetation. The e f f e c t of g l a c i a t i o n i s evident by the U-shape of the v a l l e y and the rounded ridge tops. The T e r t i a r y s i l t c l i f f s , common along the r i v e r , can be seen i n the lower right-hand corner. F i g . 2. The upland region of the Fraser Plateau showing the gently r o l l i n g country and c h a r a c t e r i s t i c pattern of vegetation. The ridge tops, g u l l i e s and v a l l e y s are forested while grassland associations dominate the open slopes. Pseudotsuga men z i e s i i var. glauca i s the dominant tree species with •.Populus"tremuloides and Picea glauca occurring i n the g u l l i e s and v a l l e y s . Agropyron spicatum and Poa spp. are the dominant grasses. 10 Mountains on the east and southeast. Drainage of the central region of the Interior Plateau i s to the west by way of the Fraser River and i t s tributaries. The study centred on the Fraser Basin and Fraser Plateau parts of the Interior Plateau. The area north of Williams Lake i s in the Fraser Basin which i s an irregularly shaped area of low r e l i e f extending from Williams Lake, northward to McLeod Lake. It has a f l a t or gently r o l l i n g surface and for the most part l i e s below the elevation of 3000 feet. The underlying bed rock i s mostly of Permian or ear l i e r age and belongs to the Cache Creek Group (Tipper 1959). It consists largely of chert, a r g i l l i t e , limestone and greenstone. There are some localized areas of plateau lavas. These are mostly basalt and andesite of Miocene age although some lavas may be as young as Pleistocene (Tipper 1959). The plateau lavas are generally not thick, probably 500-1000 f t at the most. Most of the basin i s covered by g l a c i a l d r i f t and alluvium, and bed rock i s exposed i n only a few places. These deposits average in depth from 25 to 50 f t although i n some places they are as deep as 600 to 700 f t (Tipper 1959). Ice movement during the Pleistocene has been judged to have been northward as based on the orientation of drumlins formed in the g l a c i a l d r i f t (Holland 1964). The Fraser Plateau l i e s west of the Fraser River and includes the part of the study area centred in the Chilcotin region. It i s a f l a t to gently r o l l i n g country with large areas of undissected upland at elevations between 3000 and 5000 f t . The Plateau i s cut by deep U-shaped, glaciated valleys, whose floors l i e at elevations of 1400 to 2000 f t . The geology of the Fraser Plateau i s poorly understood and only general statements are possible. Most of the Plateau i s underlain by gently dipping plateau lava flows (Tipper 1959, Holland 1964). These are of late Miocene or Pliocene age and consist mostly of olivine basalts and andesites. 11 The flows have steep escarpments along the rivers and almost horizontal upper surfaces. The existing lava i s concentrated largely between the elevations of 3000 and 4500 f t and i s believed to represent the remains of a large lava plain from which tongues extended along the major valleys and depressions. These lavas provide a parent rock for the s o i l which i s rich i n basic cations, especially magnesium and calcium. Below the lavas along the Chilcotin River are exposed large c l i f f s of s i l t and silstone which are believed to be of Tertiary age. Most of the Plateau i s covered by gl a c i a l d r i f t and i t i s estimated that less than 5% bedrock i s exposed (Holland 1964). Much of the d r i f t was moulded into drumlin—like landforms during the Pleistocene and these provide most of the r e l i e f . During the last glaciation, the ice movement across the Plateau i s believed to have been i n a north to northeastward direction. Fig. 1 and 2 i l l u s t r a t e the physiography of the Chilcotin region. Soils At the present time there i s no published description of the soil s of this region. Based on observations made during this study i t appears that soil s representative of a l l six orders of the Canadian s o i l c l a s s i f i c a t i o n scheme are present in this area. Soils classed in the Chernozemic and Brunizolic Orders are the most common. It appears that the most common s o i l forming process i s melanization. Soils of the Gleysolic, Regosolic and Solonetzic "Orders are of localized importance. Soils belonging to the Podzolic order are rare in this region. However, there i s evidence that Podzolization i s occurring as integrades to the Podzolic Order from the Brunizolic and Chernozemic .Orders are present. A detailed account of the soil s i s given with the association descriptions. 12 Climate The climate of the area i s controlled largely by the presence of the Coast Mountains to the west which act as an ef f i c i e n t barrier to the westerly wind. Air masses moving eastward from the Pacific lose most of their moisture i n passing over the mountains. Thus the study area i s i n a rain-shadow region and i s di s t i n c t l y dry. The climate i s characterized as microthermal subhumid continental (Dfb) according to Kfippen's cla s s i f i c a t i o n (Chapman 1952; Krajina 1965) and as subhumid according to that of Thorthwaite (Sanderson 1948). c In Table 1 climatic summaries are presented for Big Creek and Williams Lake, the two closest Meteorological Stations. The temperature and precipitation data are based on a 30 year average for Big Creek and on a 10 year average for Williams Lake("Temperature Normals for Br i t i s h Columbia" 1965 and "Precipitation Normals for Br i t i s h Columbia" 1965). At Big Creek, which i s at the western boundary of the study area, the mean annual temperature i s 36.3° F. The mean monthly temperatures are above 32°F for the months of April through October, the highest being 56.4°F in July and the lowest being 13.2°F in January. The highest mean maximum monthly temperature i s 71.5°F i n July and the lowest mean minimum monthly temperature i s 1.8°F i n January. The annual precipitation averages 12.63 inches and occurs as a summer maximum with 6.06 inches recorded during the months of June through September. The average annual snowfall i s 49 inches occurring mainly in the months of November through March but snow has been recorded for every month of the year except July and August. Based on the data from the Williams Lake Meteorological Station, the area appears warmer and more moist than that of Big Creek. At Williams Lake the mean annual temperature i s 43.5°F. The mean monthly temperatures are above 32°F for months of March through October, the Table 1 Temperature and Precipitation Summaries for Big Creek and Williams Lake, British Columbia Recording Station Mean Annual Temp (degrees) No. Months with Mean Temp Above 32°F Mean Max Monthly Temp (degrees F) Mean Min Monthly Temp (degrees F) Mean Annual Precipi-tation (inches) Mean Annual Snowfall (inches) Big Creek 51°44' N, 123°02' W Elevation - 3720' 36.3 71.5 1.8 12.63 49.0 Williams Lake 52°10' N, 122°05' W Elevation - 1945' 43.5 80.0 14.1 14.9 40.9 0 o highest being 64.4 F in July and the lowest being 22.2 F i n January. The highest mean maximum monthly temperature i s 80.0°F in July and the lowest mean minimum monthly temperature i s 14.1°F in January. The mean annual precipitation i s 14.9 inches of which 8.2 inches occurs during May to September. The mean annual snowfall i s 40.9 inches occurring mainly i n the months of December through February. Snow has never been recorded in June, July or August. Detailed temperature observations on a microclimatic scale were made as part of this study and are presented in Chapter VI. 15 IV THE ECOSYSTEM UNITS The ecosystem i s a basic unit in ecology and can be defined as an energy driven complex of organisms and i t s controlling environment (Billings 1965). . Tansley (1935) originated the concept of the ecosystem and considered i t to be flexible, and fundamental to ecology. He recognized that ecosystems could exist at different biological levels of organization and be of various sizes and kinds. In this study the concept i s similarly applied. Ecosystems are considered here to be both concrete and abstract and to vary from detailed to very broad levels of organization. Ecosystem units are dealt with at levels of organization ranging from the concrete and detailed level of the plant community (individual plot) through the abstract and successively broader levels of the subassociation, association alliance and order. A l l of these units are applied within the zonal ecosystem concept of Krajina (1965). Comparable ecosystematic structures have been developed in British Columbia by Orloci (1964) and Brooke (1966). Methods of Analysis Two reconnaissance trips were made at the beginning of the study (1) — one i n May 1967, to the area north of Williams Lake and one in July 1967 to the Fraser Plateau. During these t r i p s , observations were made on the com-position and structure of the vegetation and a comprehensive collection of plants was obtained and identified. As a result, a l i s t of tentative plant associations based on dominance and physiognomy was prepared. Potential communities for sampling were located i n accordance with the tentative associations and the following selection c r i t e r i a : J. Krajina accompanied the author on both tr i p s . 16 (1) A cornmunity had to be uniform in composition and structure, f l o r i s t i c a l l y and environmentally, (i.e. homogeneous). (2) A community had to be large enough to allow the incorporation of a sample plot of predetermined size. This ensured that edge effect would be minimal and that association fragments (Braun-Blanquet 1932, page 25) would not be sampled. (3) A community had to occur as a repeatable ecological unit throughout the study area. A l l communities were sampled using a single plot method. Forest communities were sampled with a 20 m x 20 m (400 sq m, 1/10 acre) plot and non-forest communities were sampled with a 10 m x 10 m (100 sq m, 1/40 acre) plot. Plots were subjectively placed i n communities selected for study using a Brunton compass and metallic tape. This careful placement of sample plots allowed an accurate description of associations with a minimum of samples. The vegetation was analyzed following the quantitative and qualita-tive phytosociological methods developed by Ztirich Montpellier School (Braun-Blanquet 1932, Becking 1957, Krajina 1933). Percentage cover estimates were made for the following vegetation layers where present. A—Tree Layer—woody plants over 33" in.height. Sublayers - over 66 f t A 2 " 49 f t to 66 f t A 3 - 33 f t to 49 f t B—Shrub Layer—woody plants between 1 f t and 33 f t i n height Sublayers B x - 6 f t to 33 f t (high shrub) B 2 - 1 f t to 6 f t (low shrub) C—Herb and Dwarf Shrub Layer—Herbaceous plants and woody plants less than 12 inches high. 17 D—Bryophyte and Lichen Layer E—Epiphytic Layer Species were l i s t e d by strata 'and a subjective estimate of species significance was made for each, using the eleven point Domin-Krajina scale (Krajina 1933). Estimates of sociab i l i t y or dispersion patterns were made for l i s t e d species using an eleven point scale after Krajina (1933). Both scales are given in Appendix I. Unknown species were assigned a descriptive name and collected for positive determination. Quantitative and qualitative data were obtained on the physiographic factors of slope angle, exposure, latitude, longitude, elevation, landform type, and pattern of topography. Notes were made on the evidence of f i r e history, amount of grazing and the type and degree of erosion. Estimates of the percentage of ground surface covered by humus and l i t t e r , exposed mineral s o i l , decaying wood and rock were also made for each plot. A total of one hundred and thirty one plots was analyzed. Plant Identification and Nomenclature Unknown vascular plants collected were identified using the following manuals: "Vascular Plants of the Pacific Northwest", Vol. 2-5 (Hitchcock et a l . 1955-1964); "The Flora of Idaho" (Davis 1952) ; "Illustrated Flora of the Pacific States" (Abrams 1940-1951); "Flora of Alberta" (Moss 1959); "Flora of Alaska" (Hulten 1968); "Manual of the Grasses of the United States" (Hitchcock 1950) ; "The L i l y Family (Liliaceae) of British Columbia" (Taylor 1966); "The Ferns and Fern A l l i e s of Bri t i s h Columbia" (Taylor 1963). Lichen collections were identified by Dr. C. D. Bird of the University of Calgary. Bryophyte collections were identified by Mr. F. M. Boas. Carex collections were identified by Dr. V. Bedner, Dr. V. J. Krajina identified some of the more d i f f i c u l t vascular plants and checked the identifications of a l l specimens of V 18 the family Gramineae. A l l plant collections are deposited as voucher specimens in the Herbarium of the Department of Botany, University of British Columbia. The authorities for species referred to in the text and tables are given in Appendix II. Variety status of species i s not indicated in the text or tables but i s assigned where appropriate in the checklist (Appendix II). It should be mentioned that the dominant tree species, Pseudotsuga menziesii, referred to in this dissertation i s the interior variety glauca. r S o i l Sampling and Analyses One s o i l p i t was dug in each plot and the profil e described by horizon. The following were included i n the descriptions: horizon depth and thickness; evidence of mottling; presence of coarse fragments; efferves-cense with dilute HC1; and root distribution. A total of 432 s o i l samples w a s collected for chemical and textural analyses. Soil samples were screened through a 2 mm screen and the less than 2 mm size fraction collected. To determine the source of the parent material some of the coarse fragments collected were tentatively identified by Dr. G. E. Rouse of the Department of Botany and Geology. Textural analysis on the less than 2 mm size fraction of the mineral soi l s was done by the revised hydrometer method (Bouyoucos 1951) , using a reciprocal shaker to agitate the s o i l suspension. The textural cla s s i f i c a t i o n followed was that of the United States Department of Agriculture (sand = 2.00 to 0.05 mm; s i l t - 0.05 to 0.002 mm; clay, less than 0.002 mm). This method was selected because of i t s simplicity and rapidity. It should be noted that the hydrometer method does not c a l l for soils to be pretreated by HC1 to destroy carbonates and with H2O2 t o destroy organic matter. These materials are dispersed and measured i n the main group 19 separates (Bouyoucos 1951). Chemical analyses were made on the less than 2 mm size fraction of the s o i l s . Determinations of carbon, total nitrogen,total phosphorus and cation exchange capacity were done by Mr. B. von Spindler of the Department of Soil Science, University of Bri t i s h Columbia. The determinations of pH and exchangeable calcium, magnesium, potassium and sodium were performed in the Department of Botany. Carbon determinations were made using a Leco total carbon analyzer and the results were expressed directly in per cent total carbon. Total nitrogen, which i s expressed as a percentage, was measured by a macro Kjeldahl method (NH-j d i s t i l l e d i n boric acid, and titrated with sulphuric acid). Carbon:nitrogen ratios were calculated from these data. The dilute acid-fluoride extraction method (method 1) of Bray and Kurtz (1945) as adapted by the Department of S o i l Science, University of Bri t i s h Columbia was used to colorimetrically determine total phosphorus (Metson 1961). To extract the exchangeable cations (calcium, magnesium, sodium and potassium), s o i l samples were leached with 1 N ammonium acetate (pH adjusted to 7) and f i l t e r e d gravimetrically following a method adapted by the Department of S o i l Science, University of Br i t i s h Columbia from Peech et a l . (1947). The concentrations of the cations were then determined from the leachates on a Perkin-Elmer, model 303, atomic adsorbtion spectrophotometer. The results were expressed i n meg/100 g of s o i l . For so i l s with high salt concentrations, the exchangeable cation determinations w i l l be slig h t l y high as the leaching process tends to extract, otherwise unavailable cations from soluable salts. Cation exchange capacity (CEC) was determined using the leached s o i l after washing with ethyl alcohol and then d i s t i l l a t i o n of ammonia into boric acid and t i t r a t i o n with dilute sulphuric acid (method of Department of 20 S o i l Science, U n i v e r s i t y of B r i t i s h Columbia). S o i l pH was determined with a Beckman model N pH meter on s o i l samples mixed to a paste consistency and allowed to e q u i l i b r a t e (Wilde and Voigt 1955). Vegetation Synthesis and C l a s s i f i c a t i o n Synthesis of the a n a l y t i c a l data was the second phase of t h i s study. Sampled p l o t s were grouped according to the c r i t e r i o n of f l o r i s t i c s i m i l a r i t y i n t o associations following standard p h y t o s o c i o l o g i c a l methods. Constancy and average species s i g n i f i c a n c e were c a l c u l a t e d f o r species by a s s o c i a t i o n . Constancy i s a s y n t h e t i c character expressing the frequency of occurrence o f a species w i t h i n an a s s o c i a t i o n when a l l sample p l o t s are of the same s i z e . I t was c a l c u l a t e d by expressing the number of p l o t s of occurrence as a percentage of the t o t a l p l o t s . Constancy percentages were expressed on the following f i v e - c l a s s s c a l e . Class Percentage I 0-20 II 21-40 II I 41-60 IV 61-80 V 81-100 Average species s i g n i f i c a n c e i s considered as an i n d i c a t i o n of the importance of a species w i t h i n an a s s o c i a t i o n . I t was c a l c u l a t e d by summing the species s i g n i f i c a n c e estimates and d i v i d i n g by the number of p l o t s i n the a s s o c i a t i o n . The associations were r e l a t e d and compared using constancy and average species s i g n i f i c a n c e data i n a synthesis table (Table 83, page 223 ). Only species which had occurred i n at l e a s t one a s s o c i a t i o n with a constancy of 60% or greater were used i n formation of the t a b l e . Thus the e f f e c t of 21 sporadic species was removed. From the table, characteristic species were determined for each association. These are species which reach maximum importance (high constancy and high average species significance) i n the association under consideration. Associations for which good characteristic species could not be found were reduced to the rank of subassociations for which characteristic species are not necessary and habitat conditions become paramount for differentiation (Krajina 1933). Differential species (Braun-Blanquet 1932, p. 59, Krajina 1933) were determined for a l l subassociations. The associations were united into the higher units of alliances and orders. Environmental as well as f l o r i s t i c data were used i n the forma-tion of higher units to ensure an ecosystematic cl a s s i f i c a t i o n . Characteristic species were determined for each category formed. Finally the characteristic combination of species (Braun-Blanquet 1932e Krajina 1933, Brooke 1966) was determined for each association. These are species, which taken as a group, best characterize the association under consideration and show i t s f l o r i s t i c relationships to the corresponding alliance and order. The ecosystem units were named following standard phytosociological practice to indicate systematic rank. Unit designations are formed from the generic name of a characteristic species as follows: Order: - e t a l i a Alliance: -ion Association: -etum Subassociation: -etosum Description of the Plant Associations In this section the associations and where appropriate, the subassociations, are characterized environmentally and f l o r i s t i c a l l y . Each 22 H i e r a r c h i c a l Arrangement of the Ecosystem Units Described for the Cariboo Zone SUBASSOCIATION ASSOCIATION Caricetum ros t r a t a e C a r i c i o n rostratae C a r i c e t a l i a rostratae Carico - Salicetum monticolae S a l i c i o n monticolae S a l i c e t a l i a Scirpetum v a l i d i S c i r p i o n v a l i d i S c i r p e t a l i a v a l i d i P u c c i n e l l i o -Hordeetum j u b a t i D i s t i c h l o -Spartinetum g r a c i l i s D i s t i c h l i o n s t r i c t a e P u c c i n e l l i e t a l i a a i r o i d i s , Muhlenbergio -Betuletum glandulosae Muhlenbergio -Betulion glandulosae B e t u l e t a l i a glandulosae juncetosum b a l t i c i antennario -poetosum secundae Poo - Elymetum c i n e r e i Antennario -Poetum secundae Agropyro -Balsamorhizetum s a g i t t a t a e Stipetum r i c h a r d s o n i i Agropyretum s p i c a t i Agropyro -Artemisietum t r i d e n t a t a e Opuntio - Stipetum comatae Agropyro -Juniperetum scopulorum S t i p i o n columbianae Agropyrion s p i c a t i Koelerio -Agropyretalia s p i c a t i calamagrostido - ) Arctostaphylo - Junipero -Pseudotsugetum *glaucae pseudotsugetosum *glaucae ) Calamagrostido -) Pseudotsugetum *glaucae pinetosum contortae ) Rhytidiadelpho - Pleurozio -Pseudotsugetum *glaucae Arctostaphylo -Pseudotsugion *glaucae Calamagrostido -Pseudotsugion *glaucae Pseudotsugetalia menziesii poo - calamagrostido -populetosum tremuloidis l o n i c e r o -caricetosum leptopodae Poo - Calamagrostido -Populetum tremuloidis Carico - Piceetum glaucae Poo - Calamagrostido -Populion tremuloidis Carico - Piceion glaucae P i c e e t a l i a glaucae Equiseto - Piceetum glaucae Equiseto - Piceion glaucae habitat i s rated trophotopically and hygrotopically according to the scheme of Progrebniak (1930), and Krajina (1969). The soi l s are classed according to the Canadian System of Soil Classification (N.S.S.C.C. 1965). Comparisons, where necessary, are made to the Canadian System of Soil Classification (N.S.S.C.C. 1968). The associations are described and discussed by alliances and orders following the scheme presented i n Table 2. The ecosystem units are arranged, physiognomically, into two sections, namely, non-forest vegetation and forest vegetation. Within the non-forest section, units are arranged along a gradient of decreasing moisture from the Caricion rostratae to the Agropyrion s p i c a t i . Within forest vegetation section the ecosystem units are arranged along an increasing moisture gradient from the Arctostaphylo — Pseudotsugion *glaucae to the Equiseto - Piceion glaucae. The presentation of the ecosystem units according to this scheme allows the relationships between them to be easily recognized. The complete synthesis table l i s t i n g characteristic species for a l l associations, alliances, and orders i s given at the end of this chapter on page 2.23as Table 83. The explanations for symbols and abbreviations used in the vegetation, environment and s o i l s tables are given i n Appendix III. Caricetalia rostratae Caricion rostratae Caricetum rostratae (ref. Tables; 3, 4, 5, 6, 83, and Fig. 3) Characteristic Combination of Species Order, Alliance and Association Characteristic Species Calamagrostis neglecta Carex aquatilis Carex rostrata Hippuris vulgaris 24 Table 3 Caricetum rostratae Plot Data Number of Plots Plot No. Plot Size (m2) Date analyzed Elevation (ft) Locality Physiography Landform Relief shape Exposure Slope gradient (°) Layer coverage (%) C layer D layer Plot coverage (%) Humus and l i t t e r Water Soil Hygrotope Trophotope Erosion Drainage Horizon depth (in) surface subsurface 1 2 3 4 5 114 112 104 113 115 100 100 100 100 100 30/8 26/8 14/8 26/8 27/8 1968 1968 1968 1968 1968 3400 2460 3500 3500 3550 FP - FP FP FP FP 51°44' 51044. 51°44' 51°43' 51°44' 122°52' 122 0 53 ' 122°39' 122°54' 122°53 91 8 95 100 86 12 96 100 shallow lake ... f l a t ... ,..neutral..., 0 90 6 98 100 85 10 100 100 hydric to (hygric) permesotrophic . n i l ...... impeded .... 89 6 100 100 0-12 12-35+ 0-13 13-26+ 0-12 12-28+ 0-14 4-26+ 0-12 12-24+ Parent material sediments Table 4 Caricetum r o s t r a t a e Number of P l o t s 1 2 3 4 5 P l o t No. 114 112 104 113 115 P l o t S i z e (m2) 100 100 100 100 100 E l e v a t i o n ( f t ) 3400 3460 3500 3500 3550 C Layer Sporadic species C Layer 8 Calamagrostis canadensis 9 Carex p r a e g r a c i l i s Avg Species Constancy S i g n i f i c a n c e 1 Carex r o s t r a t a 8.6 8. ,5 8. 7 8 .6 8. .6 V 8. 0 2 Carex a q u a t i l i s 6.3 6. ,3 7. 3 5 .3 6. ,3 V 6. 0 3 Calamagrostis neglecta 2.1 3. ,2 4. 2 3 .2 3. .1 V 3. 0 4 Hip p u r i s v u l g a r i s - 2. , 1 2. 2 2 .1 1. ,1 IV 1. 4 5 Ranunculus s c e l e r a t u s - 2. ,+ 1 .+ II 0. 6 6 Epilobium p a l u s t r e 1.1 + , ,+ II 0. 3 D Layer 7 Drepanocladus aduncus 4.2 5. ,2 5. ,2 4 .2 4. ,2 V 4. 4 TOTAL SPECIES ( i n c l . sporadics) 7 5 4 6 5 114(1.1) 113(1.1) 10 Juncus b a l t i c u s 114(1.1) D Layer 11 Amblystegium serpens 114(1.1) 26 The Caricetalia rostratae i s considered to be related to the European Phragmitietalia described by Koch (1926), mainly on the basis of habitat s i m i l a r i t i e s . Similarly, the Caricion rostratae has a strong a f f i n i t y with the European Magnocaricion elatae (Koch 1926). The Caricetalia rostratae i s represented i n the Cariboo Zone by a single alliance and a single association. The Caricetum rostratae develops on the Fraser Plateau i n shallow, well drained, lakes at elevations over 3200 f t above sea level. The lakes are formed in g l a c i a l stream depressions and are interconnected by small streams. Water movement through the lakes i s continuous although slow. In the shallow parts of these lakes the Caricetum rostratae forms closed communities while in deeper parts of the lakes open communities develop and bodies of open water are present. The only release from submergence of this association occurs near the edges of the lakes where the water recedes below the s o i l surface i n the late f a l l . However, even i n such cases, the s o i l remains saturated and free water i s always present. The hygrotope i s therefore rated as hydric but may occasionally be lowered to subhydric. This association i s considered to be aquatic. From 95% to 100% of the surface of the association i s covered by a layer of Carex l i t t e r which i s present as a floating mat during submergence. There i s no evidence of surface erosion but rather because of the aqueous situation, some deposition of mineral s o i l i s probably taking place. The s o i l has two horizons. The surface horizon varies from 12 to 14 inches in thickness and contains an accumulation of organic matter with measured carbon ranging from 2.5% to 42.3%. The subsurface horizon i s a strongly gleyed mineral horizon. Organic matter, as a result of deposition, i s present in this horizon, and the percentage of measured carbon ranges from 1.4% to 13.4%. 27 The s o i l i s formed from a parent material Of sediments. Plots 114 and 115, because of a high sand and gravel content probably represent f l u v i a l sediments, while the other plots, a l l of which have finer sediments, are probably of a lacustrine origin. However, because the soils were under water sedimentation bands were not observed. The textural class of the surface horizon ranges from sandy loam to clay loam. These measurements are only approximate because the organic matter content may interfere with the texture determination (Bouyoucos 1951). The subsurface horizon varies i n textural class from sandy loam to loam. In both horizons the s i l t and sand fraction i s greater than the clay fraction which i s similar to the soils on the surrounding uplands. The s o i l reaction i s neutral to alkaline in both horizons with measured pH values ranging from 7.4 to 8.1. The cation exchange capacity i s high i n the surface horizon corresponding to the accumulation of organic matter and decreases considerably in the subsurface horizon as does the organic matter content. Exchangeable cations and phosphorus are present i n high concentrations near the surface and decrease i n amount down the p r o f i l e . Exchangeable calcium i s generally present i n higher amounts than exchangeable magnesium due possibly to the higher s o l u b i l i t y of calcium salts in water, particularly carbonates and sulfates, and to the higher calcium content of organic matter. The habitat i s considered to be permesotrophic to eutrophic because of the favourable pH and high concentrations of exchangeable cations. Nitrogen i s present in moderate amounts in the surface horizon but the carbon:nitrogen ratios are relatively high indicating that the organic matter accumulated in this horizon may not contain sufficient nitrogen for i t s decomposition and thus a competition for nitrogen between higher plants and microorganisms may result. Nitrogen i s present i n lower amounts in the subsurface horizon but the carbon:nitrogen ratios are more favourable which Number of Plots Plot No. Surface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments Subsurface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments Table-5 Soil Texture Caricetum rostratae 1 2 3 4 5 114 112 104 113 115 L CL SiL SL L 14 30 22 8 12 36 49 54 34 44 50 21 24 58 44 None SL L SL L SL 11 24 9 23 10 11 41 47 44 17 78 35 44 33 73 g. None None None g. 29 Table 6 Soil Chemical Analysis Caricetum rostratae Number of Plots Plot No. Surface Horizon 1 114 2 112 3 104 4 113 5 115 C% N% C/N P ppm Na K Ca Mg CEC PH 42.3 1.35 31.3 36.0 2.08 .52 29.0 40.2 103.7 7.4 11. 6. .5 .21 .9 .0 .76 .50 15.2 14.5 24.8 7.8 4.9 .23 21.3 10.0 .87 .30 12.8 24.6 36.4 7.9 17.3 .83 20.8 16.0 2.28 .86 29.8 3.8 45.3 8.0 32.2 .96 46.7 13.0 1.36 1.24 34.8 28.2 76.3 7.5 Subsurface Horizon C% 13.4 1.3 N% .69 .08 C/N 19.4 16.3 P ppm 11.0 9.0 Na .72 .74 K .43 .16 Ca 18.8 17.9 Mg 6.7 10.1 CEC 32.8 22.0 pH 7.6 7.7 .0 ,15 .0 .0 .61 .35 17.8 20. 15. 17. 40. 7. 1.4 .09 15.6 8.0 1.1 .19 7.1 19.9 10.7 8.1 8.4 .45 18. 7. 17 7 7 0 38 53 9 1 26.8 7.8 30 suggests that nitrogen i s available for the growth of higher plants. Compared to t e r r e s t r i a l s o i l s , the aeration of these submerged soils i s considered to be poor even though some water movement i s occurring. Thus a reducing atmosphere w i l l exist and anaerobic decomposition w i l l be favoured over aerobic decomposition. This probably results i n a reduction i n the rate of decomposition which w i l l l i m i t the a v a i l a b i l i t y of nitrogen and other nutrients bound in the accumulated organic matter. The soi l s of the Caricetum rostratae are classed either as Orthic Humic Gleysols (horizon sequence Ah, Cg) i f the surface horizon has less than 30% organic matter or as Rego Gleysols (horizon sequence L-H, Cg) i f the surface horizon contains more than 30% organic matter. The Caricetum rostratae i s structurally simple, consisting of a well developed C layer with a coverage ranging from 85% - 91% and a poorly developed D layer covering 6% - 12% of the sampled area. Carex rostrata and Carex aguatilis are constant dominants with average species significances of 8.0 and 6.0 respectively. Calamagrostis  neglecta i s the only other constant dominant and i s present with an average species significance of 3.0. Hippuris vulgaris, although occurring with a constancy of only class IV and an average species significance of 1.4, i s considered as a characteristic species because i t i s exclusive to this association. Calamagrostis canadensis i s present as a sporadic species where the pH i s close to neutral. The sporadic occurrence of Juncus balticus and Carex praegracilis, both characteristic of semi-terrestrial and t e r r e s t r i a l sites, indicates the shallowness of the water. The D layer i s composed largely of one species> Drepanocladus  aduncus which occurs as a constant species with an average species significance of 4.4. The Caricetum rostratae has a history of slight grazing, as the 31 Fig. 3. The Caricetum rostratae showing the dense growth of Carex rostrata and Carex aquatilis. The open body of water, in which Hippuris vulgaris can be seen, i s typical of this association. Fig. 4. The Carico - Salicetum monticolae showing the closed nature of the shrub layer dominated by Salix spp. The dominance of the C layer by Carex rostrata and Carex aquatilis shows the similarity of this association to the Caricetum rostratae. 32 shallow water communities are grazed i n the late f a l l . In very dry years the Caricetum rostratae may be cut as "swamp hay" on some parts of the Fraser Plateau. Sal i c e t a l i a Salicion monticolae Cario (rostratae) - Salicetum monticolae (ref. Tables; 7, 8, 9, 10, 83, and Fig. 4) Characteristic Combination of Species Alliance and Association Characteristic Species Salix arbusculoides Salix monticola Aster junciformis Calamagrostis canadensis Galium trifidum Mnium rugicum Rhynchostegiella compacta Important Companion Species Carex aquatilis Carex rostrata Calamagrostis neglecta Juncus balticus The Salicetalia i s an order proposed to unite associations character-ized by Salix species. In this study i t i s represented by one alliance, the Salicion monticolae, and one association, the Carico (rostratae) - Salicetum monticolae. The Carico - Salicetum monticolae i s found along the stream channels connecting shallow lakes located in g l a c i a l stream depressions. It also develops in local depressions which were formerly parts of shallow lakes. The surface topography of this association i s f l a t and the exposure i s neutral. It usually adjoins the Caricetum rostratae but i s a few feet higher in r e l i e f . This association i s flooded annually and remains submerged during the early part of the growing season. By mid-summer the water table has Table 7 .Carico (rostratae) - Salicetum monticolae Plot Data Number of Plots Plot No. Plot Size (m2) Date analyzed Elevation (ft) Locality Physiography Landform Relief shape 1 2 3 4 5 127 128 126 129 130 100 100 100 100 100 4/9 4 /9 30/8 5/9 5/9 1968 1968 1968 1968 1968 3200 3250 3300 3300 2600 FP FP FP FP FP 5 1 ° 4 4 ' s i " ^ 1 5 1 ° 4 4 ' 5 1 ° 4 4 ' 51°42 1 2 2 ° 5 1 ' 1 2 2 ° 5 1 ' 1 2 2 ° 4 8 ' 1 2 2 ° 4 8 ' 1 2 2 ° 5 7 ' Depres-sion edge of stream channel f l a t Exposure Slope gradient (°) 0 0 0 0 0 Layer coverage (%) Bi layer 52 58 48 52 48 B2 layer 22 24 18 24 18 C layer 88 84 94 86 91 D layer 29 26 45 35 36 Plot coverage (%) Humus and l i t t e r 96 96 95 93 96 Water 100 (temporary) Soi l Hygrotope hydric - hygric Trophotope Erosion Drainage Horizon depth (in) surface subsurface permesotrophic ..... n i l .... impeded ... 0-10 10-30+ 0-11 11-26+ 0-13 13-26+ 0-11 11-38+ 0-10 10-32+ Parent material organic matter and sediments Table 8 Carico (rostratae) - Salicetum monticolae Number of Plots 1 2 3 4 5 Plot No. 127 128 126 129 130 Plot Size (m ) 100 100 100 100 100 Elevation (ft) 3200 3250 3300 3300 3600 sub Avg Species Pi Layer layer Constancy S i g n i f i c a n c e 1 S a l i x monticola 1 7.3 8.2 5.3 6.3 6.2 V 6.4 2 5.1 5.2 4.2 3.2 4.2 - 3.8 2 S a l i x arbusculoides 1 2.1 3.3 4.4 5.4 5.4 V 4.2 2 3.2 4.2 3.2 5.2 3.2 - 3.6 3 S a l i x brachycarpa 2 3.2 4.2 - - 3.2 V 2.0 4 S a l i x b a r c l a y i 2 2.+ - 2.+ — II 0.8 c Layer 5 Carex r o s t r a t a 7.5 8.6 8.6 8.4 8.5 V 7.8 6 Carex a q u a t i l i s 6.4 6.4 6.5 6.3 6.7 V 6.2 7 Calamagrostis neglecta 4.1 5.2 5.1 4.2 5.2 V 4.6 8 Aster junciformis 2.1 3.2 3.2 4.1 3.2 V 3.0 9 Juncus b a l t i c u s + .+ + .+ 2.1 1.+ 1.+ V 1.0 10 Calamagrostis canadensis 3.2 - 1.+ 1.1 2.1 IV 1.4 S a l i x brachycarpa - 2.2 1.+ 2.1 1.+ - 1.2 11 Taraxacum o f f i c i n a l e - 1.+ 2.+ 2.+ 1.1 IV 1.2 12 Galium t r i f i d u m - 2.1 1.+ - 2.1 III 1.0 13 Hordeum jubatum 1.+ - - I I I 0.4 D Layer 14 Drepanocladus aduncus 6.2 5.2 7.3 6.2 6.2 V 6.0 15 Rhynckestegiella compacta 3.2 3.2 2.2 3.2 3.2 V 2.8 16 Mnium rugicum - 3.2 4.2 4.2 3.2 IV 2.8 17 Bryum w e i g e l l i i - 2.2 3.1 - - II 1.0 TOTAL SPECIES ( i n c l . sporadics) 16 16 19 15 14 Sporadic species C Layer 18 Carex p r a e g r a c i l i s 19 Epilobium pulustre 127(3.2) 126(+.+) 21 Poa i n t e r i o r 126(+.+) 22 Polygonum hydropiperoides 126(+.+) 23 T r i g l o c h i n palustre 127(1.+) 35 generally receded to below the s o i l surface but free water i s always present in the profile within approximately six inches of the surface. Soil drainage i s thus rated as impeded. This habitat i s considered to be hydric to hygric and the Carico - Salicetum monticolae i s judged to be a semi-terrestrial association. The s o i l surface i s covered by an extensive l i t t e r layer composed of the leaves of Salix and Carex. This material forms the major source of s o i l organic matter. The s o i l consists of two recognizable horizons. The surface horizon i s an organic-mineral one, varying from 10 to 13 inches i n thickness and has a carbon content ranging from 14% to 26.5%. It overlies a predominantly organic horizon with measured carbon ranging from 14.5% to 45.3%. The subsurface horizon i s regarded to be the surface horizon of a previously formed Humic Gleysol or Rego Gleysol. The present s o i l appears to have been formed by deposition of alluvium carried in during flooding and organic matter formed i n s i t u . The s o i l i s considered to be regosolic and to be evolving from a s o i l similar to that of the Caricetum rostratae. It i s classed as a buried s o i l . Texturally, the surface horizon varies from a sandy loam to a s i l t y loam. Sand and s i l t are most abundant s o i l particles and are mixed with pa r t i a l l y decomposed organic matter. No particles are present greater than 2 mm i n size. These results are only approximate because the organic matter content may interfere with the texture analysis. Texture was not analyzed for the sub-surface horizon because of the high organic matter content. The surface horizon has a circumneutral reaction with pH values ranging from 6.4 to 7.4. The subsurface horizon i s weakly alkaline with pH values in the range of 7.4. Exchangeable cations are present i n high amounts with calcium dominating the exchange complex. The high exchangeable calcium concentrations, Table 9 Soil Texture Carico - Salicetum monticolae Number of Plots Plot No. Surface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments Subsurface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments 1 2 3 127 128 126 L SL SL 23 10 13 42 38 34 35 52 53 SL SL SL 9 10 11 35 38 35 56 52 54 None 37 Table 10 Soil Chemical Analysis Carico - Salicetum monticolae Number of Plots 1 2 3 4 5 Plot No. 127 128 126 129 130 Surface Horizon C% 17.1 26.5 15.3 23.8 14.7 N% .84 1.07 .64 .87 .63 C/N 20.4 24.8 23.9 27.4 23.3 P ppm 23.0 28.0 14.0 9.0 17.0 Na .44 .54 .92 1.04 1.32 K .16 .24 .38 .34 .88 Ca 25.6 17.0 59.6 44.2 42.0 Mg 16.4 20.2 20.4 23.0 19.6 CEC 46.3 88.3 60.3 71.5 42.5 pH 7.1 6.4 6.4 6.5 6.6 Subsurface Horizon C% 40.7 37.8 N% 1.34 1.06 C/N 30.4 35.7 P ppm 36.0 16.0 Na 1.52 .36 K .46 .12 Ca 35.8 31.1 Mg 27.8 17.2 CEC 111.7 84.0 pH 7.6 7.2 45.3 21.0 14.5 .99 1.06 .21 45.8 19.8 21.4 18.0 18.0 7.0 .68 1.68 .82 .28 .76 .54 46.8 31.0 65.8 14.6 13.0 20.4 136.5 74.8 20.6 7.4 7.4 7.4 38 which increase with depth are thought to be due partly to the high s o l u b i l i t y of calcium salts and partly to the release of calcium from decomposing plant remains. Phosphorus occurs in relatively high concentrations and increases in concentration down the profil e as does the organic matter content. Because of the circumneutral s o i l reaction phosphorus i s readily soluble and available. The cation exchange capacity i s very high, because of the high amount of organic matter, and a maximum value of 136.5 meg/100 g was recorded i n the subsurface horizon. This habitat i s rated as permesotrophic. Nitrogen con-centrations are high and increase with depth. However, the carbon:nitrogen ratios are also high, especially i n the lower horizons. This indicates that the organic matter present contains insufficient nitrogen to satisfy the microflora requirements and thus a competition for nitrogen between microflora and higher plants may result. Aeration i s poor because these soi l s are water saturated. Under such conditions a reducing atmosphere exists and anaerobic decomposition i s favoured over aerobic decomposition which results in slow decomposition and an accumulation of organic matter. The odour of ammonia and hydrogen sulfide, both products of reduction from plant remains, was noticed to be present i n the subsurface horizons. Structurally, the vegetation of the Carico - Salicetum monticolae consists of four recognizable horizons. The C layer i s best developed with percentage cover ranging from 84% to 94%, followed by the B-^ layer which varies in cover from 48% to 58%. The B^ and D layers are less well developed with cover ranges of 18% to 24% and 26% to 45% respectively. The B^ layer i s dominated by Salix monticola which i s present with a constancy of Class V and an average species significance of 6.4. The only other species of this layer i s Salix arbusculoides which has an average species significance of 3.8. 39 The layer i s composed of Salix arbusculoides, Salix brachycarpa and Salix barclayi. The presence of woody plants i n a dominant role i n this association i s indicative of the elevated topographic position and semi-terrestrial s o i l s . The C layer i s dominated by Carex rostrata with an average species significance of 7.8 and Carex aquatilis with an average significance of 6.2. These species, which are characteristic of the Caricetum rostratae, are important companion species i n this association even though the habitat has been altered from their optimal one. The Carico - Salicetum monticolae habitat i s considered to be i n a state of flux; t e r r e s t r i a l enough to allow the establishment of Salix spp. but s t i l l aqueous enough to be within the amplitude of the aquatic Carex spp. Juncus balticus, a species characteristic of t e r r e s t r i a l subhygric to hygric sites i s present here as a constant non-dominant with an average species significance of 1.0. Calamagrostis canadensis occurs with a constancy of Class IV and i s believed to be present because of the weakly acidic to neutral reaction of the surface horizon. However, this habitat i s s t i l l within the amplitude of Calamagrostis neglecta (characteristic of the Caricetum rostratae) which i s a constant species here, with an average species significance of 4.6. Aster junciformis, and Galium trifidum because of their exclusive-ness for this association are considered as characteristic species. Drepanocladus aduncus with an average species significance of 6.0 i s the major species of the D layer. Rhynchostegiella compacta and Mnium  rugicum are the only other important constituents of the D layer. These species occur mostly at the base of willow clumps where they are sl i g h t l y elevated above the s o i l surface. The Carico - Salicetum monticolae appears to have a history of slight grazing by cattle as well as browsing by native ungulates. The Sc i rpetum v a l i d i developed around the edges of an a l k a l i n e pond which i s formed i n a p o s t -g l a c i a l s t ream d e p r e s s i o n . S p a r t i n a g r a c i l i s dominates the foreground v e g e t a t i o n b o r d e r i n g the Sc i rpe tum v a l i d i . 41 Scirpetalia v a l i d i Scirpion v a i i d i Scirpetvim v a l i d i (ref. Tables; 11, 12, 13, 14, 83, and Fig. 5) Characteristic Combination of Species Order, Alliance and Association Characteristic Species Scirpus validus Chenopodium rubrum Ranunculus sceleratus Rumex maritimus The Scirpetalia i s considered to be closely related to the European Order Juncetalia maritimi L*Br. B l . 1939 (cited from Szafer 1966)] as both contain associations with similar habitat characteristics. One alliance and one association compose this Order i n the Cariboo Zone. The Scirpetum v a l i d i i s found i n alkaline ponds formed in shallow post-glacial stream depressions i n the upland areas (over 2900 f t elevation) of the Fraser Plateau. Some of the larger ponds have intermitent drainage outlets, however most have no visible inlets or outlets. Their water levels appear to be maintained mostly by runoff. These ponds appear stagnant and contain high concentrations of soluble salts. The Scirpetum v a l i d i develops around the edges of these ponds and remains submerged for most of the growing season. Only by late August has the water receded, due largely to evaporation, to expose the s o i l surface. However, water may s t i l l be extracted from the surface horizon by squeezing and free water persists in the subsurface horizon. Soil drainage i s regarded to be impeded. Therefore the habitat of this association i s considered to be hydric to sub-hydric. The surface topography i s f l a t and the exposure i s neutral. There i s no evidence of erosion; instead, because of the topographic position sedimentation i s probably taking place. ~~ 42 Table 11 Scirpetum v a l i d i Plot Data Number of Plots 1 2 3 4 5 Plot No. 116 118 117 119 120 Plot Size (m2) 100 100 100 100 100 Date analyzed 27/8 1968 28/8 1968 28/8 1968 29/8 1968 29/8 1968 Elevation (ft) 2900 2950 2970 3050 3500 Locality FP 51°46' 122°32' FP 51°46' 122°33' FP 51047' 122°32' FP 51°46' 122°35' FP 51°43' 122°47 Physiography Landform Relief shape Exposure Slope gradient (°) f l a t .... ....neutral... 0 0 0 0 0 Layer coverage (%) C layer 96 4 94 6 96 11 80 3 92 6 Plot coverage (%) Humus and l i t t e r Water 91 100 96 100 96 100 89 100 92 100 Soil Hygrotope Trophotope Erosion Drainage Horizon depth (in) surface subsurface 0-12 12-24+ hydric to hygric . hypereutrophic . n i l impeded 0-13 13-24+ 0-16 16-25+ 0-15 15-26+ 0-12 12-26+ Parent material sediments Table 12 Scirpetum v a l i d i Number of P l o t s P l o t No. P l o t S i z e (m2) E l e v a t i o n (ft) C Layer 1 Scirpus v a l i d u s 2 Chenopodium rubrum 3 Rumex maritimus 4 Ranunculus s c e l e r a t u s 5 Hordeum jubatum D Layer 6 Drepanocladus aduncus 116 118 117 119 120 100 100 100 100 100 2900 2950 2970 3050 3500 9.6 9.7 9.7 8.5 9.5 3.2 3.2 2.2 4.3 3.3 5.3 2.2 3.3 2.2 2.2 2.1 1.1 2.1 - 2.2 + .+ - + „ + 3.2 3.2 4.2 3.2 3.2 Constancy V V V IV II Avg Species S i g n i f i c a n c e 8.8 3.0 2.8 1.0 0.2 3.2 TOTAL SPECIES ( i n c l . sporadics) Sporadic species 7 Juncus b a l t i c u s 120(+.+) 8 Mentha arvensis var. g l a b r a t a 117(1.+) 9 Polygonum coccineum 116(2.+) 10 P o t e n t i l l a anserina 11 P u c c i n e l l i a a i r o i d e s 12 Tanacetum vulgare 118(1.+) 116 (+.+) 119(1.1) 44 The s o i l surface i s covered by a layer of dead Scirpus validus stems which form a floating mat during times of submergence. This material i s decomposed slowly and forms the major source of organic matter i n the s o i l . The s o i l consists of a dark surface horizon varying from 12 to 16 inches in thickness overlying a light coloured gleyed subsurface horizon. Measured carbon in the surface horizon varies from 4.6% to 27.1% with three plots containing more than 20% carbon. There i s no measureable carbon i n the subsurface horizon. Texturally, the surface horizon has a very low clay content while in the subsurface horizon clay i s the dominant textural fraction. The sampled subsurface horizons are classed as clays, s i l t y clay loams and clay loams. No particles greater than 2 mm in size were found i n either horizon. Because of the high content of fine material, the parent material i s considered to be formed from pond sediments. However, the textural difference between the two horizons suggests that the s o i l i s evolving through deposition. Wind blown s i l t s from the surrounding upland mixed with organic matter form the surface'horizon. These soils are expected to eventually become t e r r e s t r i a l . The s o i l reaction i s alkaline with pH values ranging from 7.6 to 7.9 in the surface horizon and from 8.0 to 8.1 in the subsurface. Magnesium i s available in greater amounts than calcium i n both horizons possibly because magnesium rich rocks were the original s o i l source and because the higher clay content of these soils results in magnesium being extracted from the clay l a t t i c e . The exchangeable cations are present i n substantially higher amounts in the surface horizon than i n the subsurface horizon due to secondary deposi-tion and capillary rise of dissolved salts of exchangeable bases during periods when the s o i l surface i s exposed to evaporation. The high calcium and magnesium values coupled with a high cation exchange capacity indicate that these soils are very rich and the habitat i s therefore considered to be Number of Plots Plot No. Surface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragment Subsurface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragment Table 13 Soil Texture Scirpetum v a l i d i 1 2 3 4 5 116 118 117 119 120 SL L L SL SiL 1 16 14 20 3 44 50 48 17 52 55 35 38 64 45 CL C L SiC CL 30 67 24 47 34 42 17 45 43 36 28 14 31 10 30 None cn 46 Table 14 Soil Chemical Analysis Scirpetum v a l i d i Number of Plots Plot No. 1 116 2 118 3 117 4 119 5 120 Surface Horizon C% 27.1 24.7 22.0 4.6 13.4 N% 1.08 1.34 .92 .15 .64 C/N 25.1 16.2 23.9 30.6 20.9 P ppm 24.0 16.0 19.0 9.0 21.0 Na 1.8 1.15 1.58 .68 .91 K .64 .53 .88 .89 .67 Ca 27.6 13.4 23.8 11.2 17.1 Mg 36.4 16.7 24.0 19.3 21.4 CEC 96.4 82.6 96.4 33.8 42.6 pH 7.6 7.8 7.6 7.8 7.9 Subsurface Horizon C% 0 0 N% .10 .08 C/N 0 0 P ppm 7.0 8.0 Na .41 .40 K .75 .21 Ca 9.6 9.6 Mg 15.1 14.4 CEC 18.3 16.9 pH 8.0 8.0 0 9. 9 14 18 8 .08 .0 .48 .37 .1 .4 .3 .1 0 .11 0 3.0 .64 .55 11.2 16.2 16.1 8.1 .08 0 10.Q .97 .81 9.1 13.2 22.9 8.0 47 hypereutrophic. Nitrogen may possibly be a limiting factor, as i t i s present in the subsurface horizon only as traces (.08% to 0.1%). There i s more nitrogen in the surface horizon but the relatively high carbon:nitrogen ratios suggest that most of i t i s unavailable to higher plants. The soil s are also poorly aerated because of their water-logged conditions. The low available nitrogen and poor aeration suggests that decomposition occurs slowly which accounts for the organic matter accumulation. These soils are classed i n the Gleysolic Order as either Orthic Humic Gleysols, i f the organic matter content of the surface horizon i s less than 30%, or as Rego Gleysols i f the organic matter content of the surface horizon i s greater than 30%. The Scirpetum v a l i d i i s f l o r i s t i c a l l y simple. Most of the C layer coverage i s contributed by Scirpus validus which dominates the association with an average species significance of 8.8. Chenopodium rubrum and Rumex  maritimus are constantly present beneath the Scirpus validus cover. Ranunculus  sceleratus i s the only other vascular plant occurring with regularity. Several species, including Hordeum jubatum, Juncus balticus, Potentilla anserina and Puccinellia airoides occur sporadically at the drier edges of the habitat. A l l plants present here can tolerate alkaline conditions and are capable of growing submerged. Only one bryophyte, Drepanocladus aduncus, occurred with measureable cover. This species was most common i n cattle hoof prints in parts of the association longest released from submergence. Scirpus validus i s also present in a truly aquatic community of the large fresh water lakes in the region. This community, however, was not studied. 48 Puccinellietalia airoidis Distichlion strictae The order Puccinellietalia airoidis i s proposed for the inclusion of t e r r e s t r i a l alkaline-saline associations which have characteristically solonetzic s o i l s . It i s related to the European Puccinellio - Salicornietalia (Br.-Bl. -de Leeuv 1936) but i s distinguished by higher sodium:calcium ratios. The Puccinellietalia airoidis i s represented in the Cariboo Zone by one alliance, the Distichlion strictae. This alliance i s formed in depressions or on the edges of alkaline ponds in the upland area of the Fraser Plateau. The habitats are strongly alkaline with high salt concentrations and are frequently flooded. The Distichlion strictae i s characterized by Puccinellia airoides, Hordeum jubatum, Spartina g r a c i l i s , D i s t i c h l i s s t r i c t a and Carex praegracilis. The D i s t i c h l i s association described by Daubenmire (1942) in central Washington would most like l y be placed in this alliance. Two associations are recognized in this a l l i a n c e — t h e Puccinellio-Hordeetum jubati and the Distichlo - Spartinetum g r a c i l i s . They are distinguished, f l o r i s t i c a l l y , largely on the basis of dominance of the major characteristic and constant species. 1. Puccinellio (airoidis) - Hordeetum jubati (ref. Tables,- 15, 16, 17, 18, 83 and Fig. 6) Characteristic Combination of Species Order and Alliance Characteristic Species Aster pansus Carex praegracilis D i s t i c h l i s s t r i c t a Hordeum jubatum Puccinellia airoides Spartina g r a c i l i s Association Characteristic Species Eleocharis palustris Elymus glaucus Ranunculus cymbalaria Triglochin palustris 49 Important Companion Species Juncus balticus Potentilla pennsylvanica The Puccinellio - Hordeetum jubati occurs on the edges of alkaline ponds or i n drainage pathways. The surface topography i s f l a t and the expo-sure i s neutral. This association i s flooded i n the spring, but the water level i s well below the s o i l surface for most of the growing season and by late summer free water i s not found anywhere i n the p r o f i l e . However, the B horizon remains moist and water can be extracted from the C horizon by squeezing. The hygrotope of this habitat varies from hydric i n the spring to hygric for the remainder of the season. There i s no evidence of erosion i n this association. Based on the topographic position and s o i l texture the drainage i s regarded as impeded to imperfect. Much of the water loss from the s o i l i s probably accomplished through evapo-transpiration. The s o i l surface i s covered by a thin layer of l i t t e r but some mineral s o i l was exposed i n a l l communities studied (6 to 12%). The s o i l has an A, B, C, horizon sequence formed on a parent material of sediments. The C and B horizons are strongly gleyed and a few mottles are present i n the A horizon as well. With the exception of plots 123 and 124 organic matter accumulation i s present in the A horizon and to a lesser extent also i n the B horizon. In plots 123 and 124 there was no measureable evidence of melanization Texturally the s o i l i s composed of sand, s i l t and clay size particles except for plot 124 where a few gravels were also found in the B and C horizons. There i s apparent eluviation of clay from the A horizon resulting in an accumulation of clay i n the B horizon. Measured clay in the B ranges from 24% to 61%. Sampled B horizons are classed texturally as clay loams to clays. The corresponding C horizons are s i l t loams to clay loams. Table 15 Puccinellio (airoidis) - Hordeetum jubati Plot Data Number of Plots 1 2 3 4 5 Plot No. 122 121 123 124 125 Plot Size (m2) 100 100 100 100 100 Date analyzed 29/8 28/8 29/8 30/8 30/8 1968 1968 1968 1968 1968 Elevation (ft) 2950 2980 3000 3440 3440 Locality FP FP FP FP FP 51°46' 51°46' 41°47' 51°45' 51°45' 122°31' 122°34' 122°32' 122o40' 122°40' Physiography Landform drainage drainage path ...... edge of pond path 2R,@!L 3 . 6 f S help 6 « « o « € 6 c c « c o o o « « a « 4 c e o f Id t •«•>*•••••••••••••«•• Exposure neutral Slope gradient (°) 0 0 0 0 0 Layer coverage (%) C layer 88 92 86 86 85 D layer 28 46 18 14 10 Plot coverage (%) Humus and l i t t e r 92 94 88 92 94 Mineral s o i l 8 6 12 8 6 Soil Hygrotope ............... hydric to hygric Trophotope hypereutrophic Erosion n i l Drainage impeded Horizon depth (in) A 0-5 0-3 0-4 0-5 0-4 B 5-11 3-12 4-12 5-11 4-11 C 11^ -22+ 12-22+ 12-22+ 11-24+ 11-25+ Parent material sediments 51 Table 16 P u c c i n e l l i o ( a i r o i d i s ) - Hordeetum j u b a t i Number of Plots 1 2 3 4 5 Plot No. 122 121 123 124 125 Plot Size (m2) 100 100 100 100 100 Elevation (ft) 2950 2980 3000 3440 3440 Avg Species C Layer Constancy S i g n i f i c a n c e 1 Hordeum jubatum 8.4 7.3 7.4 8.3 7.3 V 7.4 2 P u c c i n e l l i a a i r o i d e s 3.2 4.2 5.2 4.2 3.2 V 4.8 3 Carex p r a e g r a c i l i s 3.3 4.2 3.2 5.4 5.3 V 4.0 4 Aster pansus 2.1 4.1 2.1 4.1 4.1 V 3.2 5 Spartina g r a c i l i s 3.1 + .+ 3.1 4.2 4.2 V 2.9 6 D i s t i c h l i s s t r i c t a 3.+ + .+ 2.1 3.1 3.1 V 2.3 7 Ranunculus cymbalaria 2.2 3.2 2.2 2.2 2.2 V 2.2 8 P o t e n t i l l a pennsylvanica 1.1 1.1 1.+ 2.2 3.2 V 1.6 9 Juncus b a l t i c u s 4.1 5.3 3.2 4.2 - IV 3.2 10 Eleocharis p a l u s t r i s 3.1 +. + 2.1 - 1.1 IV 1.3 11 Elymus glaucus - 3.1 - 2.1 3.2 III 1.6 12 T r i g l o c h i n p a l u s t r i s - + .+ 1.+ - 2.+ III 0.7 13 Carex p r a t i c o l a 1.1 - - 1.1 1.1 III 0.6 14 Scirpus validus 1.+ 1.+ - - - II 0.4 D Layer 15 Drepanocladus aduncus 6.3 6.2 4.2 5.2 4.2 V 5.0 TOTAL SPECIES ( i n c l . sporadics) 14 15 14 15 12 Sporadic species 16 Agropyron spicatum 123(+.+) 17 Calamagrostis neglecta 121(2.+) 18 Elymus hirsutws 123(4.2) 19 Poa j u n c i f o l i a 124(+.+) 20 Poa l o n g i l i g u l a 122(2.+) 21 Poa pratensis 124(1.+) 22 T r i g l o c h i n maritima 124(2.+) 52 The s o i l reaction i s strongly alkaline i n a l l horizons because of the accumulation of basic cations and clay resulting from deposition coupled with the imperfect drainage. Measured pH values range from 7.8 to 8.9. Exchangeable calcium and magnesium are present in very high amounts with magnesium being substantially higher than calcium. This suggests that a magnesium rich parent rock was the source of the s o i l . Although the high amounts of available magnesium may be caused by the high clay accumulation, as magnesium i s an important constituent of the clay l a t t i c e . Total nitrogen measured i s low and decreases to only trace amounts in the C horizon. However, the carbon:nitrogen ratio of the A and B horizons i s also low, indicating that sufficient nitrogen i s present to satisfy the requirements of the microbial population of the s o i l . This together with the fact that s o i l aeration i s adequate throughout most of the growing season w i l l ensure active aerobic decomposition thus maintaining a nutritionally rich habitat. Exchangeable sodium i s high, particularly in the A horizon (concentrations of up to 6.8 meq/100 g were measured) which may cause some inhibition to plant growth. A thin layer of crusted salts i s present on the s o i l surface of most communities by late summer. This results from capillary rise and eva-poration of ground water. Although s o i l s a l i n i t y was not measured, i t i s probable that the A horizons of these soils contain a high concentration of salts which w i l l limit extensively the flora capable of growing in this habitat. The high concentrations of exchangeable cations in the A horizon, relative to the lower horizons, suggests that there are soluble salts composed of the measured bases present. The high cation exchange capacity and large amounts of exchangeable bases indicate that this habitat i s nutritionally very r i c h . However, the strong salt concentrations may limit the a v a i l a b i l i t y of these ions through the creation of unfavourable osmotic pressures. The trophotbpe of this ' Table 17 Soil Texture Puccinellio (airoidis) - Hordeetum jubati Number of Plots 1 2 3 4 5 Plot No. 122 121 123 124 125 A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments SiL 4 58. 38 CL 34 42 24 None SiL 25 52 23 None SiL 13 54 33 Data not avail-able None CL 31 42 27 None CL 29 39 32 None C 61 29 10 None CL 39 30 31 None CL 36 28 36 C 60 28 12 g-SiCL 34 48 18 g-CL 25 46 30 SiL 24 54 22 None L 22 48 30 None 54 Table 18 Soil Chemical Analysis Puccinellio (airoidis) - Hordeetum jubati Number of Plots 1 2 3 4 5 Plot No. 122 121 123 124 125 A Horizon C% 10.1 12.8 0 0 14.0 N% .63 .68 .07 .12 .61 C/N 16.0 18.8 0 0 22.9 P ppm 18.0 14.0 5.0 5.0 14.0 Na .59 1.06 2.9 4.9 6.9 K .52 .63 9.4 1.67 1.23 Ca 8.5 6.6 5.5 1.28 5.5 Mg 18.3 24.4 41.0 5.3 21.1 CEC 88.1 36.5 17.3 13.2 43.5 pH 7.9 8.5 7.8 8.9 8.5 B Horizon C% N% C/N P ppm Na K Ca Mg CEC pH 6.3 .26 24.2 8.0 1.30 .54 8.1 18.2 27.5 8.2 0 .06 0 8.0 .48 .13 13.1 12.5 17.3 8.1 0 9. 6 20 13 8 .06 0 87 64 5 3 5 1 7.5 .41 18.3 8.0 7.10 .92 8.1 15.6 42.6 8.5 C Horizon C% 0 0 0 0 6.1 N% .08 .08 .06 .08 .28 C/N 0 0 0 0 21.8 P ppm 4.0 6.0 6.0 6.0 4.0 Na 1.39 .38 .41 .76 5.7 K .48 .27 .14 .57 .83 Ca 9.3 8.4 14.7 10.5 8.3 Mg 17.8 19.0 15.2 15.9 14.5 CEC 3.8 13.7 12.2 23.1 26.8 pH 8.1 8.5 7.8 8.4 8.5 55 habitat i s considered to be hypereutrophic. Because of the high pH, clay accumulation and s a l t concentrations, the soi l s are placed i n the Solonetz Great Group and potentially into the Brown Solonetz Subgroup. However, because of their weak solonetzic charac-t e r i s t i c s they are recognized to intergrade towards the Chernozemic Order and might well be placed as Gleyed Solonetzic Dark Brown Chernozems. Structurally this association i s simple, having only two layers of vegetation, a well developed C layer and a poorly developed D layer. The C layer has a percentage cover of 86% to 92% while the D varies in cover from 10% to 46%. The Puccinellio - Hordeetum jubati i s dominated by Hordeum jubatum which i s constantly present with an average species significance of 7.4. Puccinellia airoides and Carex praegracilis are constant co-dominants with lower species significances, 4.8 and 4.0 respectively. Aster pansus, Spartina  g r a c i l i s , D i s t i c h l i s s t r i c t a , and Ranunculus cymbalaria are present as constant non-dominants. Potentilla pennsylvanica occurs with low significance but increases in importance in drier communities of the association. Eleocharis  palustris, Elymus glaucus and Triglochin palustris, although recorded only as non-constants, are considered as characteristic species because of their preference for this association. Eleocharis palustris, Triglochin palustris and Ranunculus cymbalaria together with Juncus balticus are good indicators of the hydric to hygric conditions. The D layer i s composed largely of one species, Drepanocladus aduncus, which occurs with a Constance of class V and an average species significance of 5.0. The regularly occurring species form a characteristic flora which i s capable of tolerating a hygrotope varying from submergence to par t i a l desiccation as well as extremely alkaline conditions with high concentrations 56 Fig. 6. The Puccinellio - Hordeetum jubati shown here bordering the Scirpetum v a l i d i . Hordeum jubatum forms almost closed stands i n this association. Fig. 7. The Distichlo - Spartinetum g r a c i l i s showing the characteristic dominance of Spartina g r a c i l i s and the sporadic occurrence of Hordeum jubatum. The Scirpetum . v a l i d i can be seen in the upper l e f t and the lighter coloured slope at the top of the picture i s dominated by the Antennario - Poetum secundae. 57 of soluble salts. Species like Agropyron spicatum, Calamagrostis neglecta and Poa pratensis which are less tolerant of these conditions occur only sporadically. The Puccinellio - Hordeetum jubati appears to have a history of only slight grazing, the effects of which are noticeable by the disturbance of the s o i l surface. 2. Distichlo (strictae) - Spartinetum g r a c i l i s (ref. Tables; 19, 20, 21, 22, 83, and Fig. 7) Characteristic Combination of Species Order and Alliance Characteristic Species Aster pansus Carex praegracilis D i s t i c h l i s s t r i c t a Hordeum jubatum Puccinellia airoides Spartina g r a c i l i s Association Characteristic Species Agropyron trachycaulum Atriplex truncata Grindelia squarrosa Polygonum aviculare Suaeda depressa Important Companion Species Juncus balticus Poa j u n c i f o l i a The Distichlo - Spartinetum g r a c i l i s i s found on three related landforms—old pond bottoms, drainage pathways and edges of alkaline ponds. The surface topography i s either f l a t or very gently sloping and the exposure i s neutral. Measured slope gradients vary from 2° to 5°. Communities of the Distichlo - Spartinetum g r a c i l i s occurring in the pond bottom depressions and the drainage pathways are flooded for short periods in the spring. Those on slopes above the alkaline ponds are rarely submerged but probably benefit from seepage temporarily. S o i l drainage i s 58 Table 19 Distichlo (strictae) - Spartinetum g r a c i l i s 1 - 2 3 4 5 6 052 053 081 080 048 049 100 100 100 100 100 100 19/8 19/8 18/7 18/7 11/8 11/8 1967 1967 1968 1968 1967 1967 2930 2930 2970 3000 3050 3090 FP FP FP FP FP FP 51°50' 51°50' 51°46' 51°47' 51°47' 51°47' 122°30' 122°30" 122°31' 122°32' 122°33' 122°34 Plot Data Number of Plots Plot No. Plot Size (m2) Date analyzed Elevation (ft) Locality Physiography Landform old pond bot- drainage edge of drainage ..torn depression.. path pond path Relief shape straight f l a t f l a t straight straight f l a t Exposure SE neutral neutral NE SW neutral Slope gradient 2 0 0 3 5 0 Layer coverage (%) C layer 84 88 84 82 67 82 D layer 0 0 0 0 3 3 Plot coverage (%) Humus and l i t t e r 90 97 90 88 79 86 Mineral s o i l 10 3 10 12 21 14 Soil Hygrotope subhygric - (hydric) Trophotope hypereutrophic Erosion n i l n i l n i l . slight n i l n i l water Drainage imperfect moderate moder- moderate ate to well Horizon depth (in) A 0-7 0-8 0-6 0-7 0-8 0-6 B 7-16 8-16 6-13 7-14 8-24 6-16 C 16-30+ 16-28+ 13-24+ 14-26+ 24-39+ 16-35+ Parent material shallow sediments shallow sediments over gla c i a l . ... over glacial d r i f t .... dr i f t ? 59 Table 20 Distichl o ( s t r i c t a e ) - Spartinetum g r a c i l i s Number of Plots 1 2 3 4 5 6 Plot No. 52 53 81 80 48 49 Plot Size (m2) 100 100 100 100 100 100 Elevation (ft) 2930 2930 2970 3000 3050 3090 Avg Species C Layer Constancy Significance 1 Spartina g r a c i l i s 8.6 8.5 8.3 8.3 7.4 7.5 V 7.7 2 Aster pansus 5.5 6.4 4.2 4.2 3.2 5.3 V 4.5 3 D i s t i c h l i s s t r i c t a 4.3 3.2 3.1 4.1 5.2 6.4 V 4.2 4 Poa j u n c i f o l i a 4.2 2.2 4.1 3.1 3.1 1.1 V 2.8 5 Carex praegracilis 3.2 4.3 3.1 3.2 2.1 - V 2.5 6 Hordeum jubatum 2.2 1.2 2.1 2.1 - 1.1 V 1.3 7 P u c c i n e l l i a airoides 2.2 1.2 3.1 1.+ - - IV 1.2 8 Agropyron trachycaulum + .+ 2.2 - 2.+ - 1.1 IV 0.9 9 Comandra umbellata - + .+ - 1.+ +.+ 1.1 IV 0.5 10 Juncus balticus 3.2 4.3 - 2.1 - - III 1.5 11 Suaeda depressa 2.1 2.1 4.2 - - - III 1.3 12 Antennaria umbrinella - - - 2.2 1.+ 2.1 III 0.8 13 Artemisia f r i g i d a - - - 1.+ 3.1 + .+ III 0.8 14 Lepidium densiflorum - - 1.+ 2.+ 2.+ - III 0.8 15 Taraxacum o f f i c i n a l e - - - 1.+ 1.+ +.+ III 0.3 16 G r i n d e l l i a squarrosa 3.1 - - - 2.+ - II 0.8 17 Polygonum aviculare - - - - 3.1 2.1 II 0.8 18 Chenopodium leptophyllum - - 2.+ 2.+ - - II 0.7 19 Erigeron acr i s - - 2.+ 1.+ - - II 0.5 20 Orthocarpus hispidus - - - - 2.+ 1.+ II 0.5 21 Poa secunda - - 2.1 1.1 - - II 0.5 22 Antennaria dimorpha - - - - 1.+ 2.1 II 0.3 23 Atriplex truncata - - - - 1.+ 1.+ II 0.3 24 Koeleria g r a c i l i s - - - - 1.1 1.+ II 0.3 D Layer (Lichens) 25 Cladonia pocillum - - - - 3.+ 3.1 II 1.0 TOTAL SPECIES(incl.sporadics) 14 13 15 18 18 17 Sporadic species 26 Agoseris glauca 053(+.+) 27 Carex pr a t i c o l a 052(1.1) 28 Chenopodium freemontii 081(1.2) 29 Elymus glaucus 052(2.2) 30 Erigeron speciosus 048(+.+) 31 Poa pratensis 080(3.1) 32 P o t e n t i l l a pennsylvanica 08K+. + ) 33 Ranunculus cymbalaria 081(2.1) 34 Smilacina s t e l l a t a 053(2.+) 35 Salicornia rubra 052(1.1) 36 Viola adunca 049(2.1) 60 classed as moderate to imperfect. Runoff i s light and was observed to cause slight water erosion in only one plot. The hygrotope varies from hydric for a short time in the spring to subhygric for most of the growing season. The s o i l surface i s covered by a thin l i t t e r layer varying i n extent from 79% to 97% of the surface area. In a l l communities studied exposed mineral s o i l was present. The s o i l i s formed from a parent material of sediments overlying g l a c i a l d r i f t . In plots 048 and 049 however, the finer material may be of aeolian origin rather than sediments. Three distinct horizons are recognizable in the p r o f i l e . The A horizon which i s dark brown contains an accumulation of organic matter with measured carbon ranging from 3.8% to 24.8%. It i s six to eight inches in thickness and contains no coarse fragments. Texturally the sampled A horizons range from s i l t loams to sandy loams. Underlying the A i s a lighter coloured B horizon. Some organic staining i s evident here although carbon i n measureable amounts, was recorded only in plot 081. Clay accumulation was present i n three of the sampled communities. S i l t and sand sized particles are the most abundant and the textural classes range from s i l t loams to loamy sands. Coarse fragments of gravel size were present in a l l samples. The C horizon i s present at a depth of 13 to 24 inches and has a high accumulation of carbonates as revealed by a strong effervescense with hydrochloric acid. Sampled C horizons range from sandy loams to sandy clays. Coarse fragments ranging i n size from gravels to stones were present in a l l samples. There are a few mottles present i n the C horizon which i s indicative of the restricted drainage. The s o i l reaction i s alkaline in a l l horizons and measured pH values range from 7.8 to 8.4. The cation exchange capacity and the concentrations of the exchangeable cations are very high indicating that the habitat i s nutritionally r i c h . Cation concentrations are highest near the surface and 61 decrease with depth. Magnesium i s present in higher amounts than i s calcium, suggesting a magnesium rich parent source of the s o i l . Concentrations of exchangeable sodium are very high in this association particularly in the A horizon where sodium concentrations of up to 27 meg/100 g were measured. This high sodium level may interfere with the exchange complex and limit plant growth. Nitrogen i s present in low amounts i n the A horizon and decreases through the B horizon to just trace amounts in the C horizon. The carbon: nitrogen ratios are highest i n the A horizon and decreases with depth indicating that nitrogen competition between the microflora and higher plants may occur near the surface. A study of the plant root distribution shows the roots to be massed i n the A horizon; only a few reach as low as the C horizon. Thus the edaphic conditions of the A horizon appear to have the greatest effect on growth of plants. The Distichlo - Spartinetum g r a c i l i s i s judged as hypereutrophic because of the medium texture of the s o i l , basic s o i l reaction and high accumulation of cations. A white salt crust probably resulting from capillary rise and evaporation of ground water containing soluble salts, was observed on the surface of four communities studied (052, 053, 081, 049). However, a second possible source of this salt crust i s from salts deposited in solution during times of flooding. These would remain at or near the surface because i n these habitats the effect of evapo-transpiration i s greater than that of leaching. The salt layer of plot 052 was analyzed and found to contain 245 meg/100 g of sodium, 250 meg/100 g of magnesium, 28 meg/100 g of calcium and 4.68 meg/100 g of potassium. This suggests that the salts present are largely those of sodium and magnesium. Number of Plots Plot No. A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments Table 21 Soil Texture Distichlo (strictae) - Spartinetum g r a c i l i s 1 2 3 4 5 6 052 053 081 080 048 049 SiL SL SiL LS SL SL 7 9 12 3 8 5 52 42 51 18 47 49 41 49 37 79 45 46 None L 21 48 31 g-L 23 33 44 g. LS 2 26 72 g. SiL 14 51 35 g-SiL 0 59 41 g-SiL 1 61 38 g-CL 33 27 40 g.c.s. L 24 26 50 g.c, CL 33 31 36 g.c. SCL 27 23 50 g.c. SL 3 47 50 g.c.s, SL 1 48 51 g.c. to 63 Table 22 Soil Chemical /Analysis Distichlo (strictae) - Spartinetum g r a c i l i s Number of Plots 1 2 3 4 5 6 Plot No. 052 053 081 080 048 049 A Horizon C% 14.7 24.8 11.3 3.8 9.5 8.9 N% .78 .97 .46 .18 .23 .41 C/N 18.8 25.6 24.6 21.1 41.3 21.7 P ppm 16.0 16.0 23.0 9.0 13.0 16.0 Na 8.43 10.95 27.2 7.3 1.20 13.47 K 1.79 1.41 2.51 1.56 2.56 2.31 Ca 4.0 8.3 7.0 5.8 5.5 16.8 Mg 31.7 34.2 20.1 19.2 10.6 38.3 CEC 61.7 69.3 62.3 24.3 52.3 52.4 pH 8.0 8.2 8.2 8.4 7.8 7.8 B Horizon c% 0 0 4.7 0 0 0 N% .11 .03 .16 .12 .61 .10 C/N 0 0 29.4 0 0 0 P ppm 4.0 3.0 17.0 12.0 7.0 6.0 Na 8.61 1.76 4.0 1.01 7.39 2.06 K .83 .51 1.63 .3 1.73 1.47 Ca 5.5 7.5 8.4 8.5 7.8 11.6 Mg 21.7 11.8 16.0 13.5 28.3 44.8 CEC 12.1 12.0 26.8 21.4 21.4 24.3 PH 8.3 8.2 8.1 8.4 8.3 8.0 C Horizon C% 0 0 0 0 0 0 N% .08 .06 .21 .04 .07 .10 C/N 0 0 0 0 0 0 P ppm 4.0 5.0 5.0 4.0 5.0 5.0 Na 2.17 2.18 1.38 .98 8.96 2.17 K 1.60 .18 .36 .39 1.67 1.60 Ca 8.5 10.0 7.3 4.3 7.5 10.3 Mg 13.0 11.5 15.6 15.5 12.8 13.0 CEC 14.3 9.9 12.9 11.7 24.7 14.3 pH 8.3 8.3 8.1 8.2 8.3 8.3 64 Because of the capillary rise of ground water, the A horizon i s also expected to contain strong concentrations of soluble salts. The higher concentrations of sodium as compared to calcium i n both the A horizon and the salt crust, indicates that the s o i l i s of a sodic nature. This i s supported by the presence of Suaeda depressa which is characteristic of sodic soils and by the only sporadic occurrence of Salicornia rubra which i s more characteristic of alkaline-calcic s o i l s . The soi l s of the Distichlo - Spartinetum g r a c i l i s are classed in the Solonetz Great Group and tentatively into the Brown Solonetzic Subgroup of the Canadian s o i l c l a s s i f i c a t i o n scheme. However, because of their relatively weak solonetzic characteristics they are thought to grade strongly toward the Chernozemic Order where they would be classed as Dark Brown Solonetzic Chernozems. The Distichlo - Spartinetum g r a c i l i s i s dominated by Spartina  g r a c i l i s which i s constantly present with an average species significance of 7.7. Aster pansus and Di s t i c h l i s s t r i c t a are constant co-dominants with average species significances of 4.5 and 4.2 respectively. A l l three of these species are indicators of alkaline habitats. The remaining constant species are: Carex praegracilis, Poa j u n c i f o l i a , and Hordeum jubatum. Puccinellia airoides and Juncus balticus are important non-constants which are probably established because of the alkaline, hygric conditions. Atriplex truncata, Suaeda depressa, Grindelia squarrosa, and Polygonum aviculare, although present with low constancy, are considered as characteristic because of their exclusiveness to this association. Orthocarpus hispidus, Poa secunda, Antennaria dimorpha, and Koeleria g r a c i l i s occur in the drier parts of the association. The bryophyte and lichen occurrence i n this association i s almost negligible. Only one species, Cladonia pocillum was recorded. The apparent absence of bryophytes i s probably due to the strong concentrations of salts on The Muhlenbergio - Betuletum glandulosae showing the characteristic hummocky surface topography formed by the clumps of Betula glandulosa. Muhlenbergia richardsonis i s the dominant species between the hummocks. Young trees of Picea glauca are common in this association suggesting a successional advancement to forest. 66 the s o i l surface. This association appears to have a history of only moderate grazing. Betuletalia glandulosae Muhlenbergio (richardsonis) - Betulion glandulosae Muhlenbergio (richardsonis) - Betuletum glandulosae (ref. Tables; 23, 24, 25, 26, 83, and Fig. 8) Characteristic Combination of Species Order, Alliance, and Association Characteristic Species Betula glandulosa c Salix brachycarpa Erigeron acris Muhlenbergia richardsonis Sisyrinchium sarmentosum Cladonia cariosa Important Companion Species Arctostaphylos uva-ursi Carex praegracilis Aster pansus Juncus balticus Poa juncifolia Hordeum jubatum Potentilla anserina Koeleria g r a c i l i s Aster campestris Carex concinna Rosa acicularis Antennaria anaphaloides The Order Betuletalia glandulosae i s considered characteristic of subalpine and subarctic regions where i t was previously described by Lambert (1968). In the Cariboo Zone, this Order i s represented by a single alliance and a single association. The Muhlenbergio - Betuletum glandulosae i s an association of restricted distribution on the Fraser Plateau. It develops at elevations greater than 3000 feet above sea lev e l , in depressions, at the base of exposed 67 Table 23 Muhlenbergio (richardsonis) - Betuletum glandulosae Plot Data Number of Plots 1 2 3 4 5 Plot No. 135 131 134 133 132 Plot Size (m2) 100 100 100 100 100 Date analyzed 10/9 6/9 10/9 9/9 6/9 1968 1968 1968 1968 1968 Elevation (ft) 3050 3100 3100 3200 3400 Locality FP FP FP FP FP 51°43' 51°44' 51°44' 51°44' 51°44' 122037' 122°48' 122°38* 122°51' 122°50 Physiography Landform i o e « s « e c * « depression Relief shape ........ > e o « e * c * o o hummocky Exposure ........ .. neutral Slope gradient (°) 0 0 0 0 0 Layer coverage (%) A3 layer - 4 - -B\ layer 6 - 0 2 B2 layer 56 48 52 68 44 C layer 82 86 88 74 82 D layer 18 18 14 12 8 Plot coverage (%) Humus and l i t t e r 94 92 92 92 94 Mineral s o i l 4 6 6 . 6 4 Soil Hygrotope (hydric) - hygric - (subhygric) . eutrophic Erosion n i l Drainage Horizon depth (in) A 0-6 0-6 0-5 0-7 0-4 B 6-14 6-12 5-8 7-10 4-16 C 14-25+ 12-20+ 8-22+ 10-25+ 16-24+ Parent material alluvium Table 24 Muhlenbergio (richardsonis) - Betuletum glandulosae Number of Plots 1 2 3 4 5 Plot No. 135 131 134 133 132 plot Size (m2) 100 100 100 100 100 Elevation (ft) 3050 3100 3100 3200 3400 sub Avg Species A Layer laver Constancy Significance 1 Picea glauca 3 - i.+ - - - III 0.6 B Laver Picea glauca 1 - 2.+ - - 3.+ 1.0 2 Betula glandulosa 2 6.3 7-3 7.3 8.4 7.3 V 7.0 3 S a l i x brachycarpa 2 3.3 2.1 3.3 2.1 2.1 V 2.4 C Laver 4 Muhlenbergia richardsonis 7.4 7.4 7.4 7.4 8.4 V 7.2 5 Arctostaphylos uva-ursi 5.3 5.3 3.2 4.2 5.3 V 4.4 S a l i x brachycarpa 4.3 4.2 5.3 4.2 5.3 4.4 6 Carex p r a e g r a c i l i s 5.3 2.2 3.2 2.1 4.3 V 3.2 7 Juncus b a l t i c u s 3.2 3.2 3.2 2.1 4.2 V 3.0 8 Aster pansus 3.2 2.+ 3.1 3.1 3.1 V 2.8 9 Koeleria g r a c i l i s 3.2 1.1 3.1 3.2 2.1 V 2.4 10 Poa j u n c i f o l i a 2.1 2.1 1.1 2.1 3.1 V 2.0 11 Rosa a c i c u l a r i s 2.1 3.1 1.1 1.+ 3.1 V 2.0 12 Agropyron spicatum 2.1 2.1 3.1 1.1 1.1 V 1.8 13 V i o l a adunca 2.+ 1.+ 2.1 3.2 1.1 V 1.8 14 A c h i l l e a m i l l e f o l i u m 1.+ 1.+ 2.+ 2.+ 2.+ V 1.6 15 Antennaria anaphaloides 2.+ 2.2 1.+ 1.1 2.1 V 1.6 16 Erigeron a c r i s 1.+ 2.+ 1.+ 2.+ 2.+ V 1.6 17 V i c i a americana 2.1 1.1 1.1 2.1 2.+ V 1.6 18 Taraxacum o f f i c i n a l e 2.+ 1.+ 2.+ 1.+ 1.+ V 1.4 19 Carex concinna - 4.2 4.2 3.2 3.2 IV 2.8 20 P o t e n t i l l a pennsylvanica 4.2 - 4.2 1.+ 2.+ IV 2.2 21 Sisyrinchlum sarmentosum 1.+ 1.+ 2.+ 1.+ IV 1.0 22 Aster campestris 1.+ 1.+ 1.+ 1.+ - IV 0.8 23 Orthocarpus hispidus 1.+ - 1.+ 1.+ +.+ IV 0.7 24 Smilacina s t e l l a t a 1.+ + .+ + .+ + .+ - IV 0.5 25 Anemone m u l t i f i d a - + .+ + .+ +.+ IV 0.4 26 Antennaria umbrinella - 2.2 2.2 1.1 - III 1.0 27 Agoseris glauca 2.+ - 1.+ +.+ - III 0.7 Picea glauca 1.+ 1.+ - - + .+ 0.5 28 Hordeum jubatum + .+ - + .+ - + .+ III 0.3 29 P o t e n t i l l a anserina 1.+ - - - 1.+ II 0.4 30 Senecio pauperculus - 1.+ - 1.+ - II 0.4 31 Thalictrum occidentale +.+ - + .+ - - II 0.3 32 Stipa r i c h a r d s o n i i - - +.+ - II 0.2 33 Parnassia p a l u s t r i s + .+ - +.+ - - II 0.2 D Laver (Brvophvtes) 34 Amblystegium serpens 5.2 5.2 4.2 4.2 4.2 V 4.4 35 Ceratodon purpureus 3.2 4.2 2.2 3.2 3.2 V 3.0 36 Tortula r u r a l i s - 3.2 - - 1.+ II 0.8 (Lichens) 37 P e l t i g e r a canina var. rufescens 1.+ 3.2 2.2 2.2 1.1 V 1.8 38 Cladonia cariosa - 1.2 - 1.+ 2.2 III 0.8 39 Cladonia chlorophaea - - - 1.+ II 0.3 40 P e l t i g e r a malacea - +.+ - - + .+ II 0.2 TOTAL SPECIES ( i n c l . sporadics) 37 34 35 35 36 Sporadic species B Layer 41 S a l i x bebbiana C Laver 42 Agropyron subsecundum 43 Aster c i l i o l a t u s 44 Astragalus dasyglottis 45 Calamagrostis neglecta 46 Cerastium arvense 47 Fragaria v i r g i n i a n a 48 P o t e n t i l l a g r a c i l i s 135(2.1) 132(2.1) 135(2.1) 134 (+. + ) 131(2.1) 133<+.+) 133(+.+) 135(2.1) 49 P u c c i n e l l i a airoides 50 S a l i x monticola 51 Solidago canadensis 52 V i o l a canadensis D Layer 53 Blastenia sinapisperma 54 Cladonia coniocraea 55 Cladonia g r a c i l i s 56 C e t r a r i a ericetorum 57 Distichium capillacftum 134(+.+) 135(1.1) 133(1.1) 135(+.+) 132(1.1) 132(+.+) 132(+.+) 131(2.2) 135(2.2) 69 slopes. These depressions are formed i n g l a c i a l stream courses which appear as shallow valleys. The surface topography is hummocky and the exposure i s considered to be neutral. So i l drainage i s judged to vary from imperfect to moderate. Free water i s present i n the profile for part of the year as evidenced by the mottling of the C horizon. Occasionally, during the spring and early summer, the association may be submerged for a short time. By late summer the s o i l of the B horizon i s moist and water may be obtained from s o i l of the C horizon by squeezing. Temporary runoff and seepage are additional factors regarded as important in maintaining the moisture conditions of this habitat. The hygrotope of this association i s considered to range from sub-hygric to hygric arid occasionally i n the spring, up to hydric. The Muhlenbergio - Betuletum glandulosae, or a variation, has been observed to be more common i n open meadows of the subalpine zone. It i s believed to be present in the Cariboo Zone largely due to local r e l i e f features which allow a cool microclimate to develop. The g l a c i a l stream courses containing the depressions with the Muhlenbergio - Betuletum glandulosae appear to act as cold a i r drainage pathways from the surrounding uplands. The local depressions further amplify this phenomenon as they trap cold a i r and thus act as frost pockets. A phenological observation supports this. Leaves of Betula and Salix were observed to be damaged by frost earlier in the autumn than were plants in neighbouring habitats. These depressions are also snow pockets and i n early March, 1969, were observed to have snow depths 2 to 4 times greater than those of the surrounding slopes. The snow accumulation i s thought to protect the vegetation against freezing, particularly during c r i t i c a l seedling stages and to provide a source of moisture at the beginning of the growing season. Over 90% of the s o i l surface i s covered by a thin l i t t e r layer 70 composed mostly of the leaves of Betula and Salix. This forms a constant source of organic matter which i s incorporated into the s o i l . The s o i l has a chernozemic A horizon varying in thickness from four to seven inches overlying a B horizon i n which some melanization has occurred. Below the B horizon i s a li g h t colored C horizon. The s o i l i s formed from a parent material of alluvium. In plots 131 and 132, sand i s the dominant s o i l fraction with rounded gravels and cobbles present i n a l l horizons. In the remaining soils coarse fragments are absent, and s i l t and clay sized particles predominate. The soil s range from gravelly sandy loams to clay loams. There i s evidence of eluviation of clay from the A horizon as a result of leaching i n plots 131, 134, and 135. The corresponding clay accumulation in the B horizon i s accompanied by a weakly columnar structure which suggests that solonization of the s o i l may be occurring. The cation exchange capacity of these s o i l s i s high as are the concentrations of exchangeable cations indicating that the sites are edaphically r i c h . The cation exchange capacity decreases from the A to the C horizon corresponding to the decrease i n measured carbon. Total nitrogen i s relatively low i n the A and B horizons but the carbon:nitrogen ratios are also low. Thus i t i s apparent that decomposition occurs readily and that there i s ample nitrogen available to satisfy the microflora requirements. Concentration of exchangeable sodium i s generally low with the exception of the A and B horizons of plot 134 which had sodium concentrations of 6.6 and 9.3 meg/100 g respectively. Since the pH of both horizons i s high (over 8.5), the excess sodium may cause a dispersal of s o i l colloids and the development of a structure unfavourable to water entry and root growth. The increased sodium content of the B horizon i s indicative of leaching. Exchangeable calcium i s present in higher con-centrations in the B horizon than in the A horizon suggesting that the A i s being degraded by leaching. This i s supported by the pH values which are Table 25 Soil Texture Muhlenbergio (richardsonis) - Betuletum glandulosae Number of Plots Plot No. A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments 1 135 2 131 3 134 4 133 5 132 SiL 15 49 36 None LS 3 21 76 g.c. L 26 34 40 None CL 34 40 26 None SL 16 15 69 g.c. L 25 49 26 None SCL 26 15 59 g.c. CL 37 37 26 None SCL 22 28 50 None SL 15 18 67 g.c. SiC 41 44 16 None SL 12 9 79 g.c. CL 38 42 21 g. SiCL 29 53 18 None LS 6 14 80 g.c. 72 Table 26 Soil Chemical Analysis Muhlenbergio (richardsonis) - Betuletum glandulosae Number of Plots Plot No. 1 135 2 131 3 134 4 133 5 132 A Horizon C% N% C/N P ppm Na K Ca Mg CEC pH 5.0 .37 13, 12, 17 20 31 8 5 0 76 13 5 1 0 0 9.8 .43 22.8 7.0 .37 1.12 13.7 19.8 38.5 7.9 6.1 .28 21.8 7.0 6.6 2.35 5.8 19.3 26.9 8.9 10 11 3 1 8 ,4 .22 .9 .0 .6 .18 .3 20.0 18.5 8.2 7.0 .41 17.5 12.0 1.12 1.63 9.9 21.4 32.6 8.1 B Horizon C% .fi N% C/N P ppm Na K Ca Mg CEC PH 2.4 .21 11.4 10.0 .48 .23 15.4 11.2 16.8 7.9 0 5. 17 15 10 8 ,12 .0 .32 .96 .0 ,3 .4 .3 8.3 • 57 14.6 17.0 9.30 2.20 7.2 19.6 42.1 9.0 28. 7. 1. .4 .05 .0 .0 .4 .66 9.3 20.5 10.0 8.7 11, 9, 12 14 14.8 8.4 1 18 7 0 45 96 6 7 C Horizon c% 0 0 0 0 0 N% .17 0.10 .13 .06 .10 C/N 0 0 0 0 0 P ppm 6.0 4.0 3.0 3.0 5.0 Na .46 .34 3.4 .87 .46 K .23 .42 1.10 .68 .98 Ca 28.7 13.1 9.8 12.8 9.8 Mg 12.5 10.0 12.5 11.9 14.1 CEC 8.3 4.6 10.8 6.3 11.3 pH 7.6 8.1 8.5 8.5 8.0 73 highest in the B horizon possibly as a result of i l l u v i a t i o n of basic cations. The s o i l reaction i s alkaline in a l l horizons. The trophotope of this habitat i s considered to be eutrophic. The so i l s of the Muhlenbergio - Betuletum glandulosae are classed as Gleyed Dark Grey Chernozems or Gleyed Solonetzic Dark Grey Chernozems. The soils of plots 132 and 135 are developed over a buried melanized horizon which indicates that vegetation other than that now present once occupied these depressions. It i s possible that the buried horizons developed under vegetation similar to the Caricetum rostratae as this association presently occupies neighbouring habitats in the stream depressions. Structurally the Muhlenbergio - Betuletum glandulosae consists of a well developed layer and a well developed C layer with cover ranges of 44% to 68% and 74% to 88% respectively. The D layer i s poorly developed with a percentage cover varying from 8% to 18%. There i s also a very poorly developed B^ layer (present in two plots) and a weakly developed layer (present in one plot). Picea glauca forms the A-j and B^ layers and i t s presence i s indicative of the cool hygric conditions of this habitat as Picea glauca grows only in moist sites in the Cariboo Zone. Betula glandulosa and Salix brachycarpa constitute the B 2 layer with average significances of 7.0 and 2.4 respectively. Salix, because of i t s growth form, i s more common in the C layer where i t has an average significance of 4.4. Both species are boreal-subarctic elements (Krajina, personal communication) and are thus considered to be indicators of the cool microclimate of this association resulting from cold a i r drainage. Muhlenbergia richardsonis, a species characteristic in the Cariboo Zone of moist alkaline areas with heavy snow accumulation, dominates the C layer with an average significance of 7.2. Arctostaphylos uva-ursi i s constantly 74 present and attains i t s best growth on the drier hummocks which are rarely flooded. Additional species on the hummocks include: Koeleria g r a c i l i s , Agropyron spicatum, Poa jun c i f o l i a , Potentilla pennsylvanica and Aster  campestris. The presence of Carex praegracilis, Aster pansus, Juncus balticus, Hordeum jubatum, Sisyrinchium sarmentosum, Potentilla anserina, Parnassia  palustris and Puccinellia airoides reflects the hygric to hydric alkaline conditions that prevail between the hummocks. Carex concinna, Rosa acicularis, Antennaria anaphaloides and Vicia americana together with Arctostaphylos uva- ursi and Picea glauca are forest species which occur in this association. They are thought to be present because of the cool frost-pocket microclimate. The most important bryophyte species i s Amblystegium serpens with an average significance of 4.4. Ceratodon purpureus and Tortula ruralis are the only other bryophytes occurring i n two or more plots. n The lichen flora i s poorly developed and confined mostly to the hummocks. The most important species are Peltigera canina var. rufescens, Cladonia cariosa, C. chlorophaea and Peltigera malacea. This association appears to have a history of moderate grazing. Koelerio (gracilis) - Agropyretalia spicati Extensive areas of the Cariboo Zone are represented by associations described in the Koelerio - Agropyretalia s p i c a t i . The soil s of these associations are formed from fine textured parent materials considered to be aeolian in origin. The habitats are rated trophically from permesotrophic to eutrophic and hygrotopically from very xeric to submesic. The order i s charac-terized^ by Agropyron spicatum, Arabis h o l b o e l l i i , Artemisia f r i g i d a , Erigeron  f l a g e l l a r i s , Koeleria g r a c i l i s , Tragopogon dubius, Tortula ruralis and Cladonia  pocillum. This order i s believed to encompass the grass type described by Whitford and Craig (1918) and the lower, middle and upper grassland zones 75 proposed by Tisdale (1947). It i s similar to the Palouse grasslands of Washington as described by Daubenmire (1942) . Two alliances are recognized for the Koelerio - Agropyretalia s p i c a t i — t h e Stipion columbianae and the Agropyrion spi c a t i . Stipion columbianae The Stipion columbianae i s an upland alliance occurring on the Fraser Plateau at elevations over 2500 f t . Hygrotopes of this alliance range from xeric to submesic. It i s characterized by cool temperatures, and frosts are frequent even during the summer (see page240 ) . The growing season i s shorter than that of the Agropyrion s p i c a t i . This alliance i s characterized by: Antennaria rosea, A. umbrinella, Aster campestris, Astragalus dasyglottis,  Carex praticola, Cerastium arvense, Festuca saximontana, Juncus balticus, Orthocarpus hispidus, Poa juncif o l i a, Poa pratensis, Potentilla pennsylvanica and Stipa columbiana. Astragalus dasyglottis, which i s a halophilous species and Juncus balticus which i s a hygrophilous species are representative of moist, saline sit e s . Thus, these species are considered to have only minor importance as characteristic species of the Stipion columbianae. The middle and upper grassland zones of Tisdale (1947) would be included i n this alliance. The alliance appears to be similar to the Agropyron -Poa Zone described by Daubenmire (1942) i n Washington. Agropyrion spicati The Agropyrion spicati i s confined to low elevations and reaches i t s best development on the slopes and bottoms of the major river valleys. Hygrotopes of this alliance range from very xeric to xeric. It i s characterized by a warmer climate and summer temperatures over 90° are common (see page ). Summer frosts are very infrequent and thus i t i s considered to have a long growing season. The alliance i s characterized by: Calochortus macrocarpus, 76 comandra umbellata, Lithospermum ruderale, Lomatium macrocarpum, Opuntia f r a g i l i s , Diploschistes canadensis, Lecidea decipiens, and Physcia muscigena. Previously described vegetation types in Br i t i s h Columbia which would be included in this alliance are: the sagebrush type and Agropyron  spicatum grass type of whitford and Craig (1918); the grassland formation of Halliday (1937); the bunch grass prairie of Rowe (1959); the lower grassland zone of Tisdale (1947) and the Agropyron spicatum (grassland) associations of Brayshaw (1955, 1965). This alliance resembles the sagebrush-grass type of Pickford (1932) and Stoddart (1941) in Northern Utah and the Agropyron-Artemisia zone of Daubenmire (1942) in Southeastern Washington. Stipion columbianae L Poo (juncifoliae) - Elymeturn cinerei (ref. Tables; 27, 28, 29, 30, 83, and Fig. 9) Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Arabis h o l b o e l l i i Artemisia fr i g i d a Erigeron f l a g e l l a r i s Koeleria g r a c i l i s Tragopogon dubius Tortula ruralis Cladonia pocillum Cladonia pyxidata Alliance Characteristic Species Antennaria rosea Antennaria umbrinella Aster campestris Astragalus dasyglottis Carex praticola Cerastium arvense Festuca saximontana Juncus balticus Orthocarpus hispidus Poa j u n c i f o l i a Poa pratensis Potentilla pennsylvanica • • • • • • -•'•>• The Poo - Elymetum c i n e r e i as developed on an o l d a l l u v i a l t e r r ace. The dominant Elymus cinereus occurs i n widely spaced clumps suggesting vegetative propagation. 78 Alliance Characteristic Species (Cont'd) Stipa columbiana Association Characteristic Species Elymus cinereus " Important Companion Species Populus tremuloides Carex praegracilis Smilacina s t e l l a t a The Poo - Elymetum cinerei occurs as isolated pockets either on old stream terraces or on benches below slopes with permanent seepage. In this study the sampled plots were a l l located on stream terraces at the base of exposed slopes but none were permanent seepage slopes. Measured slope gradients ranged from 0° to 4° and the exposure was generally neutral. The surface topography i s f l a t to straight. There i s no evidence of surface erosion in this association and the s o i l drainage i s considered to be moderate. The s o i l i s developed on a parent material of alluvium. Three horizons are present—a chernozemic A horizon varying in thickness from three inches to four inches, overlying a lighter coloured B horizon which ranges in thickness from three inches to 10 inches and a mineral C horizon which shows a strong effervescence with hydrochloric acid indicating the presence of carbonates. Texturally the sampled A horizons ranged from sandy loams to s i l t y loams and no particles greater in size than two mm were present. The B horizon i s finer textured and the samples were predominantly loams. There i s an accumulation of clay here, accompanied by a slight columnar structure in plots 037 and 073. This suggests that the A horizon is being eluviated as a result of leaching. The C horizon i s generally coarser and samples ranged from loams to loamy sands. Particles of gravel size or larger were present i n three sampled C horizons. So i l moisture content appears to increase downward in the p r o f i l e . Table 27 Poo (juncifoliae) - Elymetum cinerei Plot Data Number of Plots 1 2 3 4 5 Piot No. 073 075 072 037 136 Plot Size (m2) Date analyzed 4/7 5/7 4/7 2/8 11/9 1968 1968 1968 1967 1968 Elevation (ft) 2850 2900 3000 3040 3150 Locality FP FP FP FP FP 51°48' 51°48' 51°48' 51°47' 51°35' 122°37' 122°39' 122°37' 122°38' 122°24' Physiography Landform old Relief shape f l a t straight straight concave f l a t Exposure neutral SE W SE neutral Slope gradient (°) 0 2 1 4 0 Layer coverage (%) B 2 layer - 8 4 - • 2 C layer 88 92 91 80 86 D layer 10 8 15 38 16 Plot coverage (%) Humus and l i t t e r 94 94 95 86 97 Mineral s o i l 6 6 5 14 3 Soil Hygrotope submesic Trophotope eutrophic Erosion ni l Drainage Horizon depth (in) A 0-5 0-5 . 0-5 0-4 0-5 B 5-15 5-11 5-11 4-7 5-9 C 15-30+ 11-32+ 11-26+ 7-27+ 9-26+ Parent material alluvium 80 Table 28 Poo ( j u n c i f o l i a e ) - Elymetum c i n e r e i Number of P l o t s 1 2 3 4 5 P l o t No. 073 075 072 037 136 P l o t S i z e (m2) 100 100 100 100 100 E l e v a t i o n ( f t ) 2850 2900 3000 3040 3150 sub Avg Species 1 Populus tremuloides 2 4. , + 3. , + 3. , + I I I 2. 0 C Layer 2 Elymus cinereus 7. 3 7. . 2 7. .2 7. . 3 7 . 3 V 7. .0 3 Poa j u n c i f o l i a 7. 2 4. .1 7. .2 4. ,1 4. . 1 V 5. ,2 4 Poa p r a t e n s i s 3. 1 5. ,1 3. . + 3. 2 4. , 2 V 3. ,6 5 Taraxacum o f f i c i n a l e 4. 2 3. ,1 3. , + , + 3. ,+ V 2. ,8 6 A s t r a g a l u s d a s y g l o t t i s 1. 1 4 . 1 1. .+ 2. . 1 +. . + V 1. 7 7 A c h i l l e a m i l l e f o l i u m 1. + 1. , + 1. ,+ 4 . 1 + . , + V 1. ,5 8 Cerastium arvense 2. 1 3. . 1 3. , 1 4. . 3 IV 2. ,4 9 Carex p r a e g r a c i l i s 3. 1 2 . 1 4. , 1 2. .1 IV 2 . ,2 10 S m i l a c i n a s t e l l a t a 3. .1 2. .1 4, . 1 2 .1 IV 2. .2 11 S t i p a columbiana 2. .1 3. .1 3. .2 2. .1 IV 2 , .0 12 Juncus b a l t i c u s 3. .1 2. .1 3. .2 1. . + IV 1. .7 13 A s t e r campestris 2. , 1 3. .1 2. .+ 1. .1 IV 1. .6 14 V i o l a adunca 3. . 1 1. .1 2. .1 2, .1 IV 1. .6 15 Tragopogon dubius 1. , + 1. .+ 2, . + 1 .+ IV 0. .9 16 Carex concinna 1. .1 1, .2 6 .3 II I 1. .6 17 E r i g e r o n f l a g ' e l l a r i s 1. . 1 2. . 2 3, .1 I I I 1, .2 18 Festuca saximontana 1, .1 3. . 1 2, . 1 I I I 1, .2 19 K o e l e r i a g r a c i l i s 3, . 1 1. . + 1. . 1 I I I 1, .6 Populus tremuloides +. . + +. , + 1. . + 0. . 4 20 Anemone m u l t i f i d a +, , + +, . + +. . + I I I 0. . 2 21 Antennaria rosea 5, .2 + . + II 1. .1 22 S t i p a r i c h a r d s o n i i 3, . 1 1. . 1 II 0. . 8 23 Antennaria u m b r i n e l l a 1. . 2 2, . 2 II 0 . 6 24 V i c i a americana 1, . 1 2 .+ II 0. .6 25 Agropyron spicatum +. . + 2 .2 II 0, .5 26 A r t e m i s i a f r i g i d a 1. . 1 2 , . 1 11 0 .6 27 Galium boreale 1. . + 1 .+ II 0. . 4 28 P o t e n t i l l a pennsylvanica 1. . 1 1. .+ II 0. .4 D Layer (Bryophytes) 29 T o r t u l a r u r a l i s 4. .2 3, . 1 4 . 2 3, . 2 5. . 3 V 3 , . 8 30 Ceratodon purpureus 3. .1 1, . 1 2, . 1 2, .1 IV 1. .4 31 Amblystegium serpens 1. . 1 3, .2 3 .2 II I 1. .4 32 Bryum argenteum 1. . 1 1 .1 1 . + I I I 0. .5 33 Brachythecium salebrosum 1. . + 3. .2 II 0. .7 (Lichens) 34 C l a d o n i a p o c i l l u m 2. . 2 3, . 1 3, . 1 6. . 4 2 . 1 V 3. .2 35 P e l t i g e r a malacea 2 . 1 3. . 2 3 . 1 III 1. .4 TOTAL SPECIES ( i n c l . sporadics) 30 30 29 34 20 Sporadic s p e c i e s B Layer 36 Amelanchier a l n i f o l i a 073(3.+) 37 Symphoricarpos o c c i d e n t a l i s 073(4.2) C Layer 38 Agropyron subsecundum 075(2.1) 39 A g r o s t i s c x a r a t a 073(2.1) 40 A l l i u m cernuum 075(+.+) 41 Antennaria dimorpha 037(3.2) 42 A r a b i s h o l b o e l l i i 037(+.+) 43 Aster pansus 136(3.1) 44 Carex obtusata 037(3.1) 45 Hordourn jubatum 136(+. + ) 46 Muhlenbergia r i c h a r d s o n i s 073(1.+) 47 Orthocarpus h i s p i d u s 4 8 Penstemon procerus 49 Poa i n t e r i o r 50 Rosa a c i c u l a r i s 51 S i l e n e s c o u l e r i 52 S i s y r i n c h i u m sarmentosum 53 Solidago m u l t i r a d i a t a 54 S p a r t i n a g r a c i l i s D Layer 55 C l adonia pyxidata 56 P e l t i g e r a canina var. rufescens 57 Polytrichum junipcrinum 037(2.+) 075 (+. + ) 072(1.1) 037(1.+) 037 (1. + ) 073 (1. + ) 037(+.+) 073(2.1) 072(2.1) 037(2.1) 037(2.2) 81 The A horizon i s always dry and the B horizon i s only slightly moist. However, the C horizon i s always very moist and sometimes moisture can be exuded from the s o i l by squeezing. The higher moisture content of the C horizon i s thought to be caused partly by a high water table and partly by lateral movement of water downslope due to temporary seepage. However, free water i s probably seldom present as there i s no evidence of mottling in the C horizon. The hygrotope of the Poo - Elymetum cinerei i s considered to range from submesic up to mesic. Moisture i s believed to be an important factor in controlling the distribution of this association as the characteristic species, Elymus  cinereus, i s dependent on moist habitats. Over 90% of the s o i l surface i s covered by a thin layer of l i t t e r . Measured carbon in the A horizon i s correspondingly high, suggesting an accumulation of organic matter. The amount of carbon decreases through the B horizon and carbon i s only sl i g h t l y present i n the C horizon. The carbon: nitrogen ratios of the A horizons are relatively high indicating that the nitrogen content of the incorporated organic matter i s not sufficient to satisfy the microfloral requirements. Thus a competition for nitrogen between the microflora and higher plants may occur. The carbon:nitrogen ratios of the B and C horizons are lower, suggesting that the nitrogen present here i s available to higher plants. The cation exchange capacity i s high in the A horizon largely due to the incorporated organic matter. Recorded values range from 36.0 meg/100 g to 126.4 meg/100 g. i t decreases through the B horizon and i s relatively low in the C horizon because of the coarse texture of the s o i l . Exchangeable calcium and magnesium are present in moderate amounts with magnesium generally higher than calcium. A high concentration of exchangeable sodium i s present especially in the B horizon where concentrations of up to 17.12 meg/100 g were measured. This excess of sodium i s at the expense of potassium, as sodium w i l l Table 29 Soil Texture Poo (juncifoliae) - Elymetum cinerei Number of Plots 1 2 3 4 5 Plot No. 073 075 . 072 037 136 A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments SL 9 34 57 L 16 43 41 None LS 4 15 81 g. SL 3 45 52 SiL 2 53 45 None SiL 4 74 21 None SiL 1 52 47 None SL 3 41 56 g. SL 3 45 52 g. SL 9 46 45 L 24 38 38 g-L 20 41 39 g.c. SL 9 50 41 L 11 43 45 None L 22 37 41 None 83 Table 30 Soil Chemical Analysis Poo (juncifoliae) - Elymetum cinerei Number of Plots 1 2 3 4 5 Plot No. 073 075 072 037 136 A Horizon C% 17.4 14.6 37.4 12.7 19.3 N% .84 .61 1.16 .46 .63 C/N 20.7 23.9 32.2 27.6 . 30.6 P ppm 11.0 12.0 31.0 9.0 19.0 Na 7.51 .36 .27 1.21 .64 K 2.48 2.41 1.96 6.83 2.14 Ca 9.2 • 11.5 10.3 6.5 10.7 Mg 28.2 7.9 9.6 4.6 8.7 CEC 36.0 83.5 126.4 46.5 94.0 pH 8.2 6.8 7.0 7.1 7.5 B Horizon c% 0 1.4 7.1 7.0 17.1 N%- .08 .12 .41 .09 .84 C/N 0 11.7 17.3 7.78 20.4 P ppm 4.0 10.0 8.0 10.0 16.0 Na 3.53 .40 3.34 17.12 . 1.42 K .61 1.63 1.51 6.12 2.51 Ca 12.5 6.6 5.6 6.5 11.7 Mg 15.8 6.3 9.8 14.1 16.3 CEC 12.9 31.8 32.7 34.8 90.6 pH 8.5 6.1 6.8 8.5 8.1 C Horizon C% N% C/N P ppm Na K Ca Mg CEC pH 0 .10 0 3.0 .66 .33 12.8 6.8 4.7 8.4 8 11 1 1 6 .9 .34 .5 .0 .4 .42 .6 15.7 13.0 8.2 0 .07 0 9.0 1.12 .63 9.4 14.0 16.8 8.5 0 .06 0 3.0 7.98 .30 14.5 14.7 18.0 8.9 0 8. 2. 6. 13. .13 .0 ,38 .42 ,6 .5 16.3 9.3 84 replace potassium on the exchange complex. Also, the high sodium coupled with pH i n the range of 8.5 may cause the dispersion of s o i l colloids resulting in a structure unfavourable to root development and water entry. In such soils a further development may occur i n which dispersed clay i s moved down the p r o f i l e and forms a dense layer with columnar structure which i s inpenetrable to plant roots and water. This process appears to be occurring in plots 037 and 072. The s o i l reaction i s neutral to alkaline at the surface and becomes strongly alkaline with depth. Measured pH values of the C horizon range from 8.2 to 9.3. This increase i n pH could be due to a leaching of soluble salts by ground water and seepage. With the exception of plots 037 and 072 the s o i l s of this association are c l a s s i f i e d into the Orthic Dark Brown Chernozemic subgroup of the Canadian Soi l Classification System. Plots 037 and 072 are c l a s s i f i e d as Solonetzic Dark Brown Chernozems because of their high sodium contents and columnar B horizons. They are considered to be intermediate between the Solonetzic and Chernozemic Orders. Structurally, the Poo - Elymetum cinerei consists of a well developed C layer with a percentage cover ranging from 80% to 92%, a poorly developed D layer with a coverage ranging from 8% to 38% and a weakly developed B 2 layer with a percentage cover ranging from 2% to 8%. The B 2 layer i s composed entirely of transgressives of Populus  tremuloides which are probably stems from root suckers of Populus clones occurring on the same stream terraces. Their presence i s indicative of a relatively high water table. The C layer i s dominated by Elymus cinereus which i s constantly present with an average significance of 7.0. It i s the only characteristic species of this association. Poa ju n c i f o l i a , a characteristic species of moist 85 alkaline habitats i s the only other constant dominant with an average species significance of 5.2. Poa pratensis, Achillea millefolium, and Astragalus dasyglottis are constant non dominants, a l l present with low species significance. Smilacina s t e l l a t a and Juncus balticus with average species significances of 2.2 and 1.7 respectively are indicative of the moist habitat. Cerastium arvense, Stipa columbiana, Aster campestris, Koeleria  g r a c i l i s , Erigeron f l a g e l l a r i s , and Festuca saximontana occur as non constants with low significance. These species are more characteristic of the exposed slopes occupied by the Antennario - Poetum secundae and their presence is probably because of the very dry, less alkaline A horizon i n which most are rooted. The high alkalinity, moist subsoil as well as the presence of soluble salts i n this association i s indicated by the presence of the following halophytic species: Carex praegracilis, with a constancy of Class IV; Aster  pansus, Hordeum jubatum; and Spartina g r a c i l i s . The D layer i s dominated by Tortula ruralis and Cladonia pocillum with average species significances of 3.8 and 3.2 respectively. No other bryophytes or lichens contribute significantly to the structure of this layer. The Poo - Elymetum cinerei appears to be closely related to the Elymetum cinerei (mentioned by Brayshaw 1965) which occupies a l l u v i a l flood plains of the Thompson River Valley. The two d i f f e r , however, by the fact that the Poo - Elymetum cinerei i s developed on Chernozemic rather than on Regosolic soi l s and that i t has a large compliment of dry steppe-like plants. It i s possible that the Poo - Elymetum cinerei represents a r e l i c t association of a once more widely spread Elymetum cinerei. The association presently exists in isolated pockets where basic cations have accumulated and where the water table i s relatively high. The Poo - Elymetum cinerei maintains i t s identity through the presence of Elymus cinereus which i s probably surviving only by asexual reproduction, as at the present time the s o i l surface appears to be too dry for 86 the establishment of seedlings of Elymus cinereus. The Poo - Elymetum cinerei appears to have a history of moderate but selective grazing as Poa ju n c i f o l i a and Poa pratensis are more heavily grazed than Elymus cinereus. 2. Antennario (dimorphae) - Poetum secundae (ref. Tables; 31, 32, 33, 34, 83, and Fig. 10, 11) Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Arabis h o l b o e l l i i Artemisia frigida Erigeron f l a g e l l a r i s Koeleria g r a c i l i s Tortula ruralis Tragopogon dubius Cladonia pocillum Cladonia pyxidata Alliance Characteristic Species Antennaria rosea Antennaria umbrinella Aster campestris Astragalus dasyglottis Carex praticola Cerastium arvense Festuca saximontana Poa j u n c i f o l i a Poa pratensis Potentilla pennsylvanica Stipa columbiana Association Characteristic Species Antennaria dimorpha Lepidium densiflorum Poa secunda The Antennario - Poetum secundae i s the most common grassland association at higher elevations on the Fraser Plateau. It reaches i t s best development at elevations greater than 3000 feet. Here the climate i s cool and the growing season relatively short. The association occurs on gentle but exposed slopes. The measured slope gradients ranged from 1° to 7° . 87 Table 31 P l o t Data Number of Plots Plot No. Plot Size (m2) Date analyzed Elevation (ft) L o c a l i t y Physiography Landform R e l i e f shape Exposure Slope gradient (°) Layer coverage (%) C layer D layer P l o t coverage Humus and l i t t e r Mineral s o i l Rock S o i l Hygrotope Trophotope Erosion Drainage Horizon depth (in) Parent material Antennario (dimorphae) -antennario - poetosmn secundae Poetum secundae juncetosum b a l t i c i 1 2 . 3 4 5 6 7 8 9 10 11 12 033 071 026 030 054 029 055 077 079 078 076 082 100 100 100 100 100 100 100 100 100 100 100 100 30/7 2/7 26/7 26/7 22/8 28/7 23/8 14/7 16/7 16/7 13/7 19/7 1967 1968 1967 1967 1967 1967 1967 1968 1968 1968 1968 1968 3050 3150 3250 3300 3360 3400 3420 3300 3300 3350 3420 3540 FP FP FP FP FP FP FP FP FP FP FP FP 51*47' 51*42' 51-48• 51*49' 51*36' 51*48' 51*36' 51*46' 51*48' 51*47' 51*43' 51*44' 122*39' 122*36' 122*36' 122*35' 122*33' 122*36' 122*33' 122*52' 122*54' 122*53' 122*50' 122*51 exposed ridge slope top st r a i g h t f l a t SE neutral . . . s t r a i g h t . . .exposed slope convex .. . s t r a i g h t . 74 4 75 24 1 75 15 75 25 0 70 2 66 33 1 83 1 84 15 1 76 15 80 17 3 76 20 2 xer i c .permesotrophic. depres-sion ....concave... neutral sw 0 1 76 76 9 6 78 80 20 18 2 2 ...base of slope s t r a i g h t concave s t r a i g h t HW SW SE 3 2 2 82 8 85 13 2 .submesic.. .eutrophic. 86 12 89 11 0 ei 22 88 11 1 s l i g h t water . . s l i g h t water, .well . . . s l i g h t water, .moderate 0-4 4-9 9-21* 0-5 5-15 15-28+ 0-4 4-11 11-25+ 0-6 6-14 14-24* 0-5 5-12 12-24+ 0-5 0-5 5-15 5-11 15-26+ 11-24+ .aeolian deposit over g l a c i a l d r i f t . 0-5 0-6 0-5 0-5 0-5 5-12 6-11 5-11 5-11 5-14 12-28+ 11-26+ 11-24+ 11-24+ 14-26+ aeolian deposit over g l a c i a l d r i f t 88 32 Antennario (dimorphae) - Poetum secundae antennario - poetosum secundae juncetosum b a l t i c i Number of P l o t s P l o t No. P l o t S i z e E l e v a t i o n ( f t ) 1 Poa secunda 2 Antennaria dimorphia 3 A r t e m i s i a f r i g i d a 4 An t e n n a r i a u m b r i n e l l a 5 Poa j u n c i f o l i a 6 Cerastium arvense 7 K o e l e r i a g r a c i l i s 8 P o t e n t i l l a p e n n s y l v a n i c a 9 Antennaria rosea 10 A s t r a g a l u s d a s y g l o t t i s 11 A s t e r campestris 12 A c h i l l e a m i l l e f o l i u m 13 Festuca saximontana 14 Taraxacum o f f i c i n a l e 15 Agropyron spicatum 16 S t i p a columbiana 17 A l l i u m cernuum 18 A r a b i s h o l b o e l l i i 19 Juncus b a l t i c u s 20 Poa p r a t e n s i s 21 Carex p r a t i c o l a 22 E r i g e r o n f l a g e l l a r i s 23 S o l i d a g o m u l t i r a d i a t a 24 Lappula r e d o w s k i i 25 Lepidium d e n s i f l o r u m 26 E r i g e r o n compositus 27 Tragopogon dubius 28 Chenopodium l e p t o p h y l l u m 29 E r i g e r o n speciosus 30 Carex obtusata 31 Eriogonum h e r a c l e o i d e s 32 Comandra umbellata 33 Linum l e w i s i i 34 Lomatium macrocarpum 35 Orthocarpus h i s p i d u s 36 S i l e n e s c o u l e r i 37 Geum t r i f l o r u m 38 Rosa a c i c u l a r i s 39 Agropyron subsecundum 40 Anemone m u l t i f i d a 41 A s t r a g a l u s t e n e l l u s 42 A n t e n n a r i a n e g l e c t a 43 C r e p i s tectorum 44 Agropyron trachycaulum 45 Androsace s e p t e n t r i o n a l i s 46 S t i p a r i c h a r d s o n i i D Layer (Bryophytes) 47 T o r t u l a r u r a l i s 48 Bryum argenteum (Lichens) 49 C l a d o n i a p o c i l l u m 50 P e l t i g e r a malacea 51 C l a d o n i a p y x i d a t a 52 C a l o p l a c a s t i l i c i d i o r u m 53 Parmelia c h l o r o c h r o a 1 2 3 4 5 6 7 033 071 028 030 054 029 055 100 100 100 100 100 100 100 30S0 3150 3250 3300 3360 3400 3420 10 11 12 077 079 078 076 082 100 100 100 100 100 3300 3300 3350 3420 2540 Avg Species S i g n i f i c a n c e Avg Species S i g n i f i c a n c e Constancy A s s o c i a t i o n Avg Species S i g n i f icance 3.2 4.1 6.2 3.1 5 3 5.3 5.2 4 4 5 2 4 1 5 1 5.2 2.1 4.2 V 4 3 4.2 5.2 4.3 3.2 4 2 5.3 6.3 4 4 4 2 4 2 4 2 2.1 4.2 2.8 V 3 8 3.1 3.1 5.3 2.2 5 2 5.3 4.3 3 9 4 1 3 2 5 2 3.1 3.1 3.6 V 3 8 3.2 6.3 2.1 2.1 6 2 3.3 5.3 3 9 3 1 3 2 3 2 3.2 3.2 3.0 V 3 5 2.2 - 6.2 2.1 6 3 4.3 S.2 3 6 1 1 5 1 1 1 - 3.1 2.0 V 3 2 1.1 2.1 1.+ 3.2 2 1 2.1 2.2 1 B 6 2 4 2 4 2 5.2 4.1 4.6 V 3 0 2.1 4.2 2.1 2.1 6 3 3.1 7.3 3 7 2 1 2 1 1 1 2.1 2.1 1.8 V 2 9 2.1 3.+ 3.1 3.+ 3 + 3.+ 4.2 3 0 3 1 1 + 2 + 3.+ 3.+ 2.4 V 2 8 6.3 2.2 6.3 3.3 3 2 6.4 3.2 4 0 1 1 2 2 1.+ - 0.8 V 2 7 2.+ 2.+ 3.+ 1.+ 2 + 3.+ 3.+ 2 3 2 + 2 3 1 2.+ 2.+ 2.2 V 2 3 - +.+ 3.1 3.1 2 + 2.1 2.2 1 8 3 3 + 3 + 3.+ 3.1 3.0 V 2 3 3.+ +.+ - 1.+ 3 1 3.1 3.+ 1 9 2 + 2 + 3 + +. + 2.+ 1.9 V 1 8 2.1 3.+ 1.+ - 1 1 1.1 2.1 1 3 1 1 3 1 2.1 3.1 1.8 V 1 5 1.+ 1.+ 1.1 1.1 1 + 2.+ +. + 1 1 2 + 2 + 1 + - - 1.4 V 1 2 2.1 - 2.1 2.1 3 2 2.1 3.2 2 0 2 1 1 1 - 2.1 1.0 IV 1 5 1.+ 2.1 + . + 7.3 +. + +.+ 1 6 2 + 2 1 2.1 - 1.2 IV 1 1 1.+ +. + 2.+ - + + 1.+ 2.+ 1 0 3 + - 1.+ 0.8 IV 0 9 + .+ 1.+ - - - 0 3 2 1 1 + + + 2.+ 1.+ 1.3 IV 0 7 - - - - 2 1 - - 0 3 7 1 7 2 7 2 7.2 7.1 7.0 I I I 3 1 - 4.2 - 3.3 - - 0 9 3 1 3 2 3.1 5.1 2.8 I I I 1 7 - - - - + + - 3.+ 0 5 3 + 3 2 3 1 3.1 2.1 2.8 I I I I 5 7.3 1.+ +. + - 3.2 - 1 6 4 1 2 1 - - 1.2 I I I 1 5 - + .+ 1.+ 2.+ 2.+ - 0 8 2 + 1 1 3 1 - - 1.2 I I I 1 0 - 2.+ - +. + - - 0 4 2 + 2 + 2.+ 1.+ 1.4 I I I 0 9 - - 2.+ 1.+ 2.* +. + 0 8 1 + t + - 2.+ 0.7 I I I 0 B 1.+ +. + 2.1 - 2.1 2.2 1 1 - - _ I I I 0 6 1.+ 2.+ + .+ - 1 + 2.+ 1.+ 1 1 - - _ I I I 0 6 - + .+ - - - - 0 1 2 + 1 + 1 + 1.+ - 1.0 I I I 0 5 2.1 - - - 2 1 - - 0 4 1 + 1 1 1 + - - 0.6 I I I 0 5 2.2 3.1 3.2 - - 3.1 1 6 - - I I 0 9 3 2 2 1 3 1 2.1 - 2.0 I I 0 8 - - +. + - 2 + - 2.+ 0 6 2 + - - 0.4 11 0 5 1.+ - - - - 2.1 0 4 1 + + + - - 0.3 II 0 3 1.+ - - - - 1.+ 0 3 1 + - - 0.2 I I 0 3 1 + 1 + - 1.+ 0.6 11 0 3 + .• - - - - 0 1 + + - - 0.1 I I 0 1 2 2 3 2 - - 1.0 I 0 4 2.+ 3.+ • - - - 0 7 - - _ I 0 4 + . + 0 1 2 1 - - 0.4 I 0 3 2.+ 2.+ - - - - 0 6 _ - _ I 0 3 - - 2.+ - 1.1 - 0 4 - _ I 0 3 - - 2.+ - + . + - 0 4 - - _ I 0 2 - - - - - - 1 + 1 • - - 0.4 I 0 2 - 1.+ - - - - 0 1 1 + - - 0.2 I 0 1 + .+ - - - - - 0 2 - - - I 0 1 1 + +. + ~ 0.2 1 0 1 3.2 4.2 +.+ 4 2 +. + 3.1 2 2 3 2 4 2 3 2 4.2 5.3 3.8 V 3 0 3 1 2.1 0 9 2 1 1 1 1 + 2.2 3.2 1.8 I I I 1 4 3.2 3.2 2.1 1.1 3 2 2.1 2.1 2 3 3 1 3 1 3 1 3.2 2.1 2.8 V 2 5 1.1 - 2 1 - - 0 4 1 + 3 2 2.2 2.1 1.6 I I I 1 0 2 1 1 + 3.2 1.+ 1.4 II 0 7 - 1.1 - - - - 0 1 - 2.1 0.4 I 0 3 2.1 2.1 0 6 I 0 3 TOTAL SPECIES ( i n c l . s p o r a d i c s ) 32 33 29 22 25 27 33 Sporadic s p e c i e s C Layer 66 C l a d o n i a chlorophaea 082(1 + ) 54 A r t e m i s i a campestris 055(1 + ) 60 Polemonium pulcherrimum 076(2 1) 67 C l a d o n i a nemoxyna 055(1 1) 55 Bromus anomalus 055( + + ) 61 P o t e n t i l l a d i v e r s i f o l i a 077(1 + ) 68 C o r n i c u l a r i a a cuteata 071(2 1) 56 Chenopodium f r e m o n t i i 082(2 + ) 62 Sedum stenopetalum 078(1 1) 69 Dermatocarpon hepaticum 082(1 1) 57 Delphinium b i c o l o r 079(1 + ) 63 Senecio pauperculus 079(2 1) 70 P e l t i g e r a lepidophora 082 (1 *) 58 Heuchera c y l i n d r i c a 078(1 +) 64 S t i p a comata 033( + + ) 71 D i p l o s c h i s t e s canadensis 078( + + ) 59 Pinus c o n t o r t a 033 <• 65 Zygadenus gramincus 078(1 + ) 89 Slope exposure does not appear to be a controlling factor as slopes of a l l exposures are present. The surface topography varies from concave through straight to convex. There was evidence of slight water erosion in most plots studied suggesting that some surface runoff takes place. However, erosion by wind appears to be of more importance as dust storms were frequently observed in areas occupied by this association. Wind erosion i s thought to be affecting the vegetation both by removal of the surface s o i l as well as by s o i l blast by wind-carried particles. The s o i l drainage i s considered to range from moderate to well drained. The hygrotope of this association i s rated from xeric up to submesic. The s o i l surface i s covered by a thin l i t t e r layer varying in extent from 66% to 86% of the total surface area. Mineral s o i l was exposed in a l l plots studied and in most plots a few rocks were present on the surface. This exposure of mineral s o i l may greatly increase s o i l moisture loss by evaporation. The s o i l i s developed from a parent material consisting of a thin layer of aeolian deposits overlying g l a c i a l d r i f t . Three horizons are recognizable. At the surface i s a chernozemic A horizon developed in fine material and varying from four inches to six inches in thickness. Sampled A horizons range texturally from sandy loams to loams. Coarse fragments are generally absent but occasionally a few gravels are present. The B horizon varies in thickness from five inches to 10 inches. There i s a substantial increase in the clay content of the B horizons and texturally they range from sandy loams to clay loams with clay loams and loams being the most prevalent. Coarse fragments ranging in size from gravels to stones are constantly present. Beneath the B horizon i s a light coloured C horizon which effervesces with dilute hydrochloric acid indicating the presence of carbonates, probably Table 33 Soil Texture Antennario (dimorphae) - Poetum secundae antennario - poetosum secundae juncetosum b a l t i c i imber of Plots 1 2 3 4 5 6 7 8 9 10 11 12 Lot No. 033 071 028 030 054 029 055 077 079 078 076 082 Horizon Textural class L SL SL L SiL SL SL SL SiL SiL SL SL Clay (%) 11 8 8 14 5 7 7 3 11 10 2 2 S i l t (%) 42 38 ' 44 46 53 35 43 39 59 50 48 38 Sand (%) 47 54 48 40 42 52 50 58 30 40 50 • 60 Coarse fragments None None g. None g- None g. None None g- g- None Horizon Textural class L SiL CL CL L CL SL L SiL CL L SL Clay (%) 19 4 27 28 20 29 7 11 26 31 19 9 S i l t (%) 32 58 31 27 38 27 44 39 51 34 31 25 Sand (%) 49 38 42 45 42 44 49 50 23 35 50 66 Coarse fragments g. g.c. g.c. s. g.c.s. g.c.s. g.c. g.c.s. g- g- g.c. g.c.s. g-C.Horizon Textural class L L CL L L CL L L LS L SL SL Clay (%) 25 26 36 24 23 29 22 19 3 18 6 9 S i l t (%) 31 27 28 57 30 28 33 36 24 42 34 33 Sand (%) 44 47 36 39 47 43 45 45 73 40 60 58 Coarse fragments g.c. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s 91 Table 34 Antennario (dimorphae) - Poetum secundae antennario - poetosum secundae juncetosum baltici Number of Plots 1 2 3 4 5 6 7 8 9 10 11 12 Plot No. 033 071 028 030 054 029 055 077 079 078 076 082 A Horizon C% 6.7 18.3 10.5 8.3 12.4 9.8 21.0 19.3 8.1 18.1 21.5 8.4 U\ .32 .9 .82 .64 .74 .87 .96 1.16 .37 .76 1.13 .31 C/N 20.9 20.3 12.8 12.9 16.8 11.3 21.9 16.6 21.9 23.8 19.0 27.1 P ppm 12 19.0 10.0 11.0 16.0 9.0 13.0 16.0 19.0 18.0 18.0 13.0 Na 1.74 .11 1.52 1.17 1.18 1.87 .12 .26 .22 .20 .14 .24 K 1.54 1.07 1.28 1.79 1.28 1.79 2.05 1.44 .87 .80 1.16 1.33 Ca 7.5 7.4 6.5 6.0 9.5 7.0 7.8 8.7 7.9 8.4 10.4 12.5 Mg 4.9 5.5 5.7 5.2 5.3 4.7 7.1 6.8 6.6 6.0 5.9 6.6 CEC 12.5 76.1 37.5 32.7 68.4 42.5 61.3 61.5 64.3 121.5 78.4 38.9 PH 7.3 7.3 6.9 6.6 7.0 6.5 6.6 6.6 6.7 6.9 6.8 6.5 B Horizon C% 5.8 3.4 0 2.1 6.3 0 4.8 4.9 7.1 2.3 2.8 8.3 N% .41 .19 .05 .17 .30 .05 .09 .24 .29 .14 .15 .32 C/N 14.1 17.9 0 12.3 21.0 0 53.3 20.4 24.5 16.4 18.7 25.9 P ppm 13 14.0 8.0 8.0 12.0 6.0 10.0 13.0 9.0 6.0 8.0 12.0 Na .91 .15 1.65 1.52 .97 1.30 .76 2.58 .52 .81 .22 .45 K .77 .59 .14 .22 1.09 .22 1.09 .94 .57 .89 .73 .89 Ca 7.5 6.3 6.0 4.5 7.5 6.0 5.3 22.4 8.3 5.8 8.6 11.8 Mg 5.8 6.5 9.6 7.3 6.4 7.4 11.2 32.8 10.7 11.0 7.8 12.4 CEC 16.4 24.7 11.3 19.5 31.4 21.6 26.4 26.3 33.8 18.1 25.8 41.6 pH 7.4 7.3 7.8 7.6 7.3 7.4 7.3 7.4 7.1 7.3 6.5 7.1 C Horizon C» 0 1.0 0 0 0 0 0 0 3.3 2.8 0 0 N% .07 .07 .03 .26 .08 .05 .03 .10 .19 .17 .11 .07 C/N 0 14.3 0 0 0 0 0 0 17.4 16.5 0 0 P ppm 8.0 10.0 7.0 5.0 9.0 6.0 8.0 6.0 18.0 5.0 8.0 4.0 Na 2.09 .69 1.83 2.13 .74 2.00 .79 .63 1.17 1.22 .46 .59 K .09 .32 .13 .123 1.15 .13 1.35 .90 1.01 .70 .51 .64 Ca 11.0 9.3 8.0 10.5 10.5 8.5 10.2 5.3 13.5 5.1 13.0 12.2 Hg 10.7 5.8 11.8 12.6 9.3 7.0 13.1 12.2 12.2 11.1 17.3 11.8 CEC 10.7 18.3 12.8 24.7 19.3 8.4 16.3 13.8 38.1 12.7 15.4 13.1 pH 8.6 8.0 8.2 8.2 8.3 8.4 8.3 7.7 7.8 7.5 7.6 7.9 92 calcium carbonate. Texturally, the sampled C horizons range from loamy sands to clay loams with again loams and clay loams being the most prevalent. Coarse fragments were present i n a l l samples taken. These fragments are dominated by basalt suggesting that this material may be a prime source of the s o i l . A study of the root distribution in these profiles shows that most of the plant roots are concentrated i n the fine material of the A horizon. Root concentration decreases with depth and only a few roots are present in the C horizon. The s o i l reaction i s circumneutral i n the A horizon but becomes alkaline with depth. The A horizon contains a relatively high amount of organic matter as judged from measured carbon, which ranged from 6.7% to 21%. The humic acids released from this material may account for the relatively low pH values of the surface s o i l (6.5 to 7.3). Percent carbon and thus organic matter decreases down the prof i l e and i s generally absent i n the C horizon. Correspondingly the cation exchange capacity and phosphorus values are high in the A horizon and decrease down the p r o f i l e . Exchangeable cations are present in high amounts and increase in concentration with depth suggesting that there i s a movement of s o i l colloids down the prof i l e as a result of leaching. Calcium dominates the exchange complex in the A horizon, possibly due to the high calcium content of the incorporated organic matter. At lower levels magnesium i s present in higher amounts than calcium suggesting that the parent material i s magnesium rich. Carbon:nitrogen ratios are generally low, indicating that the organic matter contains sufficient nitrogen for decomposition and that a minimum of nitrogen competition between microflora and higher plants w i l l occur. Nitrogen i s present in high concentrations in the A horizon and 93 decreases to very Low dtuuaunts i n £ horizon.. The Antennario - Poetum Sff^JIHIIjJtiff* X S ii'nii l^y^ffH^Tngyj^ tCO fae jjT»g*yrmt"aj j^l? pippTi T f 'to? tffei'ifr rrrijjirr.T r» The s o i l s erf t h i s association are classified: into the Dark Brown . Cfayir|,|<!>i/'a<||T<r Great ©roup a*™* parofaatnlly/ into the Qrt&ic subgroup. Stnriwtl luxaTi ly,, the wq^tateioa consists of tara l a y e r s — a moderately w e l l developed C lay tag with a j^rrorotrage Oiimw-T* vr+nrfTyj, from. 71% to 86% and a poorly developed D) layer with a ciuwerage r c H i tying Prrtiiiu 1% to 22 %. The C l a y e r i s dronriinvatgdi b y Foa a<p<rwn«feB with am average species sigaiifican.ee of 4.3. amlffpiimaria (iEiiiiioEpfiiai,, gjrtoiiiiisrria frigida., antennaria - qiiiiyinrx r^ryl T *3t ^-w^ J^^ T^TI fftrrT ^  ^  are jj|,TP^iffifttWr^' as <t!>iit,|^r^"a!W>^"" *j^wfjw'frt*iii.'fiTr^yn'r,g. Other constant <t-pf*rritfaf inclLTadier Cerastionii a r u w i ^ g , PfrffiTi<ig'*ia <jr-*"-fTf «t, Potentilla gffTMffiy/lv^TtTg-a r j t j | H t - g i « r f i i u 4 f f ii» gameta,, ffiadl, rai^ET.Tgf da&;y,<jjjlm<Ltis „ &stter campestris, arni Festaca rv^-rmirmAt-spntj*, flijjaiuqiiypgni spicd:lmm wi'mp*~ with a constancy of class and an arrearage species «ET«pnT-fff ff-amm» ©f U.S. Striipa1 colamtrfffirra has an average species significance of only JI.©, brat sometimes iix local pockets assumes greater dominance,, for ggannale plot (9)3(1!) where i t has a species significance of 7.0. This i s perhaps becanse tat IL tier" maistnre- conditions exist i n these local depressions. Tui ' "ii£, I I i f^T i - T j c sm& rT;a»rffifftrr,ia. poxsjlinm.,, with average species significances of 3.0i and 2.5 respecttixrely,. are largely responsible for the structure of the D layer. T h u ^ iSnrttenmairio — Poefcnmi c j j u j ^ m i i t y t T«S represented: fay two subassociations namely, the antennario^ — poetosnnt secemdae and: the joneetosanr b a l t i c i . Ecologically they appear to d i f f e r i n moisture conditions of the habitat as controlled by txipoufgrfpfriTtc position. eorre&p«nn<itngrly ttke two have sli g h t l y different floristeic strnctaxes. 94 Fig. 10. The Antennario - Poetum secundae antennario-poetosum secundae showing the effects of grazing. Antennaria  dimorpha forms the dominant grey patches. Fig. 11. A close-up view of the Antennario - Poetum secundae juncetosum b a l t i c i showing the structure of the vegetation. Poa secunda, and Festuca saximontana are the dominant grasses and are intermixed with Artemisia fr i g i d a and Juncus balticus. The grey patch.in the centre i s a clump of Antennaria dimorpha. The community shown has been only l i g h t l y grazed i n recent years. 95 Antennario (dimorphae) - Poetum secundae 1. antennario (dimorphae) - poetosum secundae (ref. Fig. 10) Differential Species Allium cernuum Carex obtusata Erigeron compositus Androsace septentrionalis The antennario - poetosum secundae i s the driest and most wide-spread of the two subassociations. It occupies ridge tops and exposed slopes with gradients ranging from 3° to 7°. The surface topography ranges from straight to convex. The s o i l i s well drained and the hygrotope i s rated as xeric. Because of i t s exposed position, this subassociation i s strongly wind affected resulting i n l i t t l e snow accumulation during the winter. Slopes containing the antennario - poetosum secundae are usually snow free by the end of March. The s o i l reaction i s neutral i n the A horizon and increases in alkal i n i t y with depth. Measured pH values for the C horizon ranged from 8.0 to 8.6. The clay content of the C horizon i s relatively high (22% - 36%) and the s o i l has a very hard consistence. Erigeron compositus and Androsace septentrionalis are characteristic species of this subassociation. These and the d i f f e r e n t i a l species, Allium  cernuum and Carex obtusata are indicative of well drained xeric sit e s . Antennaria dimorpha, an association dominant, reaches i t s highest importance in this subassociation. Similarly Koeleria g r a c i l i s , Antennaria rosea, Antennaria umbrinella and Agropyron spicatum occur with higher significance in this part of the association because of the drier, better drained habitats. Poa ju n c i f o l i a i s present here, with an average species significance of 3.6 96 as compared to a significance of 2.0 in the juncetosum b a l t i c i . This increase i n significance i s thought to be because of the higher alkalinity of the antennario - poetosum secundae habitat. Antennario (dimorphae) - Poetum secundae 2. juncetosum b a l t i c i (ref. Fig. 11) Differential Species Juncus balticus Carex praticola Eriogonum heracleoides Chenopodium leptophylum Lappula redowskii Orthocarpus hispidus Bryum argenteum The juncetosum b a l t i c i i s a moister subassociation found at the base of exposed slopes and i n large shallow depressions. Slope gradients are almost negligible, ranging from 1° to 2°. The surface r e l i e f shape i s usually concave but ranges up to straight. Because of i t s topographic position this subassociation i s considered to benefit from temporary seepage and runoff from the slopes above. Snow accumulation i s greater and the duration i s longer in these habitats which have been observed to be snow covered u n t i l near the end of Ap r i l . S o i l drainage i s considered to be moderate and the hygrotope i s judged to be submesic. Texturally, the s o i l i s coarser than that of the antennario - poetosum secundae, particularly in the C horizon where the clay content i s much lower and percentage sand ranges from 45% to 73%. The sampled C horizons are cla s s i f i e d as loamy sands to sandy loams. This coarser s o i l w i l l allow a greater water movement to occur as a result of percolation and seepage. The s o i l reaction i s slightly acidic in the A horizon but becomes sli g h t l y alkaline with depth. It i s , however, less alkaline than the antennario - poetosum secundae. Measured pH values for the C horizon vary 97 from 7.5 to 7.9. Juncus balticus, indicative of moist habitats, occurs as a constant dominant with an average species significance of 7.0. Cerastium arvense, Carex praticola, Poa pratensis, and Aster campestris occur with a higher significance i n this moister subassociation. Eriogonum heracleoides, Orthocarpus  hispidus, Geum triflorum, and Stipa richardsonii, a l l characteristic of semi-protected moist habitats occur in the Antennario - Poetum secundae only i n this subassociation. Chenopodium leptophylum, Lappula redowskii and Bryum  argenteum because of their exclusiveness for this subassociation are considered as characteristic species. The Antennario - Poetum secundae because of i t s altitudinal position and extensiveness, forms the main part of the early summer cattle range. Therefore, this association has a history of severe grazing. The antennario - poetosum secundae appears to be more heavily grazed than the juncetosum b a l t i c i , partly because of i t s more open position on the slopes and partly because, being drier, i t has less chance for recovery from grazing. In some heavily grazed areas the grasses are less than four inches high and rarely produce seed. This grazing pressure i s responsible for the reduction in importance of grasses, particularly Agropyron spicatum and the increase in dominance of Antennaria spp., Artemisia frigida and Cerastium arvense. Grazing also appears to be increasing the effect of wind erosion here by removing the vegetative cover and disturbing the s o i l surface. 3. Agropyro (spicati) - Balsamorhizetum sagittatae (ref. Tables; 35, 36, 37, 38, 83, and Fig. 12) Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Artemisia frigida Tragopogon dubius 98 Order Characteristic Species (cont'd) Koeleria g r a c i l i s Arabis h o l b o e l l i i Tortula ruralis Cladonia pocillum Cladonia pyxidata Alliance Characteristic Species Antennaria umbrinella Stipa C o l u m b i a n a Festuca saximontana Carex praticola Antennaria rosea Cerastium arvense Poa ju n c i f o l i a Poa pratensis Potentilla pennsylvanica Association Characteristic Species Balsamorhiza sagittata Eriogonum heracleoides Penstemon procerus Important Companion Species Lomatium macrocarpum Geum triflorum Poa secunda Zygadenus gramineus Brachythecium salebrosum The Agropyro - Balsamorhizetum sagittatae i s found at elevations of over 2500 f t on the Fraser Plateau. It occurs either on slopes protected by continuous forest or i n gullies on exposed slopes. Measured slope gradients ranged from 4° to 13° on slopes with southerly and northerly exposures. Because of i t s topographic position and r e l i e f shape, which i s generally concave, this association i s considered to be subxeric to submesic. There i s evidence of slight water erosion suggesting that surface runoff i s concentrated i n the gully habitats. The association i s also considered to benefit from temporary seepage from slopes bordering the g u l l i e s . The s o i l surface i s covered by a l i t t e r layer ranging in extent from 85% to 97% of the surface area. Mineral s o i l was exposed in a l l plots 99 Table 35 Agropyro (spicati) - Balsamorhizetum sagittatae Plot Data Number of Plots 1 2 3 4 5 Plot No. 094 095 066 063 098 Plot size (m2) 100 100 100 100 100 Date analyzed 2/8 1968 ' 3/8 1968 21/6 1968 11/6 1968 5/8 1968 Elevation (ft) 2800 2850 2880 3000 3320 Locality FP 51048' 122°37' FP 51°48' 122°37' FP 51°47' 122°42' FP 51°47' 122°35" FP 51°47' 122°35' Physiography Landform gully gully protected slope gully protecte< slope Relief shape Exposure straight N SE SE NE N Slope gradient (°) 11 13 4 6 10 Layer coverage (%) Bi layer B2 layer C layer D layer 88 12 1 85 5 2 6 84 20 1 90 31 2 91 36 Plot coverage (%) Humus and l i t t e r Mineral s o i l Rock 85 12 3 85 13 2 96 3 92 8 97 2 1 Soil Hygrotope subxeric Trophotope eutrophic , Erosion slight water slight water n i l n i l slight water Drainage Horizon depth (in) A B C 0-5 5-12 12-24+ 0-6 6-13 13-23+ 0-5 5-21 21-32+ 0-8 8-22 22-30+ 0-5 5-11 11-24+ Parent material gla c i a l d r i f t ? g l a c i a l d r i f t ? aeolian deposit over glacial d r i f t 100 Table 36 Agropyro ( s p i c a t i ) - Balsamorhizetum s a g i t t a t a e S p o r a d i c s p e c i e s B Layer Number of P l o t s 1 2 3 4 5 P l o t No. 094 095 066 063 098 2 P l o t S i z e (m ) 100 100 100 100 100 E l e v a t i o n ( f t ) 2800 2850 2880 3000 3320 sub Avg Species B Layer l a y e r Constancy S i g n i f i c a n c e 1 Pseudotsuga m e n z i e s i i 1 - - 3.+ - - I I I 1.2 2 - - - - 2.+ 0.4 2 Rosa a c i c u l a r i s 2 - 4.3 3.+ 3.1 I I I 2.0 C Layer 3 Balsamorhiza s a g i t t a t a 7.1 7. 1 5.3 6.3 7.3 V 6.4 4 A n t e n n a r i a u m b r i n e l l a 6.2 6.2 3.2 4.3 4.2 V 4.6 5 Agropyron spicatum 5.2 5.2 3.1 5.4 3.1 V 4.2 6 S t i p a Columbiana 4.2 4.2 4.1 3.1 4.1 V 3.8 7 F e s t u c a saximontana 2.1 1.1 2.1 3.2 4.1 V 2.4 8 Poa secunda 4.1 3.1 2.1 3.3 4.1 V 2.4 9 A c h i l l e a m i l l e f o l i u m 2.+ 2.+ 3.+ 2.+ 2.+ V 2.2 10 A r t e m i s i a f r i g i d a 3.1 3.1 + .+ 2.2 1.1 V 1.9 11 Carex p r a t i c o l a 1.+ + .+ 2.1 2.1 2.1 V 1.5 12 Tragopogon dubius 1.+ 1.+ 1.+ 2.+ + .+ V 1.1 13 A n t e n n a r i a r o s e a 3.1 3.1 2.1 3.2 - IV 2.2 14 Eriogonum h e r a c l e o i d e s 3.2 3.1 - 3.+ 2.1 IV 2.2 15 Taraxacum o f f i c i n a l e 1.+ - 1.+ 4.2 2.+ IV 1.6 16 Zygadenus gramineus 2.+ - 2.+ 3.+ 1.+ IV 1.6 17 Lomatium macrocarpum 1.+ 1.+ - 2.+ 1.+ IV 1.0 18 Cerastium arvense - - 5.1 5.3 4.2 I I I 2.8 19 A s t e r pansus - - 3.1 2.1 2.1 I I I 1.4 20 Penstemon procerus - - 3.+ 2.+ 2.1 I I I 1.4 21 K o e l e r i a g r a c i l i s - - 2.1 2.+ 2.1 I I I 1.2 22 Heuchera c y l i n d r i c a - - 2.+ 2.1 1.+ I I I 1.0 23 Geum t r i f l o r u m 2.1 - - 1.+ 1.+ I I I 0.8 Pseudotsuga m e n z i e s i i + .+ - + .+ - + .+ 0.4 24 A r a b i s h o l b o e l l i i + .+ + .+ + .+ - - I I I 0.3 25 A s t r a g a l u s miser - - 7.1 5.3 - I I 2.4 26 A n t e n n a r i a dimorpha 2.1 4.2 - - - I I 1.2 27 Comandra umbellata 3.1 2.+ - - -I I 1.0 28 E r i g e r o n s p e c i o s u s - - 2.+ - 3.2 II 1.0 29 S t i p a comata 2.1 3.1 - - - II 1.0 30 A r n i c a s o r o r i a - - 1.+ 3.+ - II 0.8 31 Dodecatheon p a u c i f l o r u m - - 2.+ 2.+ - I I 0.8 32 Hieracium umbellatum 2.1 - 2.1 - - I I 0.8 33 E r i g e r o n compositus 2.1 2.1 - - - I I 0.8 34 Delphinium b i c o l o r - - 1.+ 2.+ - I I 0.6 35 S o l i d a g o m u l t i r a d i a t a - 2.+ - - 1.1 II 0.6 36 Linum l e w i s i i + .+ 1.+ - - - I I 0.3 37 Lappula r e d o w s k i i - + .+ - 1.+ - I I 0.3 D Layer (Bryophytes) 38 T o r t u l a r u r a l i s 3.2 3.1 4.2 6.3 5.3 V 4.8 39 Brachythecium salebrosum 2.1 - 2.2 2.1 4.3 IV 2.0 (Lichens) 40 C l a d o n i a p o c i l l u m 3.2 3.1 4.2 4.1 5.2 V 3.8 41 P e l t i g e r a malacea 2.1 1.1 2.1 2.1 3.1 V 1.8 42 C l a d o n i a p y x i d a t a 4.2 1.1 2.2 ~~ I I I 1.4 TOTAL SPECIES ( i n c l . s p o r a d i c s ) 33 30 35 36 33 43 Amelanchier a l n i f o l i a 095(1. ,+> 54 Poa j u n c i f o l i a 063(+. . + ) C Layer 55 Poa p r a t e n s i s 066(2. . + ) 56 P o t e n t i l l a p e n n s y l v a n i c a 095(1. . + ) 44 A l l i u m cernuum 066(2. . + ) 57 S a x i f r a g a o c c i d e n t a l i s 063(2, . + ) 45 Anemone m u l t i f i d a 094(1. . + ) 58 S i l e n e s c o u l e r i 094(+, . + ) 46 Chenopodium le p t o p h y l l u m 095(+. . + ) 59 S t i p a r i c h a r d s o n i i 098(3, .2) 47 C r e p i s a t r a b a r b a 063(1. . + ) D Layer 098(2 .1) 48 Descurainea p i n n a t a 063(+, . + ) 60 Bryum argenteum 49 Lepidium d e n s i f l o r u m 095(+. . + ) 61 C a l o p l a c a jungermanniae 098(2. .1) 50 Lithospermum r u d e r a l e 094(3. .2) 62 C a n d e l a r i e l l a v i t e l l i n a 094(3, .2) 51 Opuntia f r a g i l i s 095(1. .1) 63 C e t r a r i a e r i c e t o r u m 066(2 .1) 52 Poa f e n d l e r i a n a 098(2. . + ) 64 C l a d o n i a chlorophaea 063(3, .2) 53 Poa i n t e r i o r 098(2. .1) 65 P e l t i g e r a canina v a r . r u f e s c e n s 066(1, .1) 101 studied and three plots had rocks present on the s o i l surface. The s o i l i s developed from a parent material of aeolian deposits overlying g l a c i a l d r i f t . However, in the gully habitats the parent material may be mostly g l a c i a l d r i f t as the fine surface material appears to have been removed by surface runoff. Three distinct horizons are recognizable. The surface horizon i s a dark coloured chernozemic A horizon ranging in thickness from five inches to eight inches. It overlies a lighter coloured humified B horizon with a thickness range of six inches to 16 inches. The C horizon i s very light coloured and appears to be cemented possibly by calcium. It i s the only horizon which shows a reaction with hydrochloric acid, indicating the presence of carbonates, probably calcium carbonate. Texturally, the A horizon i s composed largely of sand and s i l t sized particles. A l l sampled A horizons are c l a s s i f i e d as sandy loams. In two plots, no coarse fragments were present in the A horizon; in the others a few gravels and cobbles were found. The sampled B horizons ranged from sandy loams to s i l t loams. The concentration of clay increases in the C horizon but in a l l plots sand composed over 40% of the sample with a maximum of 75% in plot 094. Coarse fragments ranging from gravels to stones were present in a l l samples. Because of the coarse texture, the soils are considered to be well drained and water movement from seepage w i l l be increased. A study of root distribution shows that the roots are largely con-centrated in the surface horizon. However, the roots of Balsamorhiza sagittata penetrate deeper and are present into the C horizon. The s o i l reaction i s circumneutral in the A horizon and becomes alkaline with increasing depth. Measured pH values of the C horizon ranged from 7.8 to 8.1. The higher alkalinity of the lower horizons may be due to the higher concentrations of basic cations. Table 37 Soil Texture Agropyro (spicati) - Balsamorhizetum saggitate Number of Plots 1 2 3 4 5 Plot No. 094 095 066 063 098 A Horizon Textural class SL Clay (%) 2 S i l t (%) 43 Sand (%) 54 Coarse fragments g.c. B Horizon Textural class SL Clay (%) 16 S i l t (%) 28 Sand (%) 55 Coarse fragments g.c.s. C Horizon Textural class LS Clay (%) 4 S i l t (%) 21 Sand (%) 75 Coarse fragments g.c.s, SL 6 47 47 g.c. SL 3 31 66 g.c.s. L 28 28 43 g.c.s, SL 1 38 61 None SL 5 33 61 g.c.s. SL 6 32 62 g.c.s. SL 3 45 52 None SL 2 39 59 g.c. L 23 31 46 g.c.s. SL 3 49 48 g-SL 6 34 40 g.c.s. CL 31 28 42 g.c.s. o to 103 Table 38 Soil Chemical Analysis Agropyro (spicati) - Balsamorhizetum sagittatae Number of Plots Plot No. 1 094 2 095 3 066 4 063 5 098 A Horizon C% N% C/N P ppm Na K Ca Mg CEC pH 7.3 .41 17.8 13.0 2.5 .57 9.5 12.5 28.6 6.8 15 13 1 8 6 41.7 7.4 3 48 2 0 21 4 2 1 22.0 1.14 19.3 13.0 .24 1.23 18.4 5.3 67.9 6.7 11.8 .46 25.7 23.0 .33 1.09 11.3 5.2 63.6 7.4 36. 1. 28. 1. 13, 1, 108, 6, 1 26 7 25.0 .39 03 3 6 3 6 B Horizon C% N% C/N P ppm Na K Ca Mg CEC PH 6.7 .31 21. 8, 1 14 5.7 26.4 7.5 6 0 17 05 3 4.8 .41 11.7 9.0 .22 1.11 12.1 7.6 22.8 7.5 3.1 .42 7-4 6.0 .16 .21 ,8 .1 ,1 .1 7 5 16 7 4.7 .32 14.7 12, 12 5 21 7 0 32 84 3 4 2 3 6.8 .29 23.4 15.0 .24 .30 18.9 3.9 65.0 7.2 C Horizon C% 1.4 0 0 0 0 N% .09 .05 .08 .04 .06 C/N 15.6 0 0 0 0 P ppm 7.0 8.0 6.0 8.0 10.0 Na .19 .35 .46 .47 .39 K .82 .82 .18 .12 .23 Ca 22.9 14.7 11.8 12.3 15.4 Mg 6.4 9.6 7.7 7.7 5.5 CEC 17.3 23.4 10.8 20.1 13.1 pH 7.8 7.9 8.0 8.1 7.7 104 Measured carbon content of the A horizon varies from 7.3% to 36.1% indicating that organic matter i s being incorporated into the s o i l . Lesser amounts of carbon are present in the B horizon and carbon was measureable in only one plot. The presence of carbon in the lower horizons suggests the movement of surface materials down the pro f i l e as a result of good drainage in these coarse textured s o i l s . The concentrations of available phosphorus, exchangeable potassium, and total nitrogen appear to be closely related to the amount of organic matter in the s o i l and decrease i n amounts with increasing depth. The carbon:nitrogen ratios are generally low suggesting that the organic matter in the s o i l contains sufficient nitrogen to satisfy the microbial populations and thus nitrogen w i l l be made available to higher plants. The cation exchange capacity i s high in the A horizon but decreases with depth due to the increased coarseness of the s o i l . Exchangeable calcium and magnesium are present in high concentrations and tend to increase in amount with depth, probably as a result of leaching. This association i s considered to be eutrophic. These soils are cl a s s i f i e d as Orthic Dark Brown Chernozems. Structurally the Agropyro - Balsamorhizetum sagittatae has four vegetation layers. The B^ layer i s present only in one plot with a percentage cover of 2%. The B 2 i s poorly developed and has a percentage cover ranging from 1% to 6%. The C and D layers are better developed with percentage covers ranging from 84% to 91% and 5% to 36% respectively. Pseudotsuga menziesii i s the only species present in the B^ layer and i t also occurs with low significance in the B 2 and C layers. The presence of Pseudotsuga menziesii i s indicative of the coarser soi l s and better moisture conditions of this habitat. Rosa acicularis, with an average species significance of 2.0, i s the dominant species of the B^ layer. The C layer i s dominated by Balsamorhiza sagittata with an average 105 species significance of 6.4. This species appears to be confined to coarser textured soi l s i n the Cariboo Zone. Other constant dominant species include: Agropyron spicatum, Antennaria umbrinella and Stipa columbiana. Festuca  saximontana, Poa secunda, Achillea millefolium, Carex praticola, Artemisia  frigida and Tragopogon dubius are present as constant non-dominant species. Non-constant species which are considered as important components of the characteristic combination of species for this association include: Antennaria  rosea, Zygadenus gramineus, Lomatium macrocarpum, Cerastium arvense, Koeleria  g r a c i l i s and Geum triflorum» Arnica sororia, Dodecatheon pauciflorum, and Delphinium bicolor, occur only with a constancy of class II, but are exclusive to this association. Eriogonum heracleoides and Penstemon procerus are considered as characteristic species because of their high preference for this association. Tortula ruralis with an average species significance of 4.8 dominates the D layer. The only other bryophyte of importance i s Brachythecium  salebrosum, whose presence indicates a moderately moist habitat. Cladonia  pocillum, Peltigera malacea, and Cladonia pyxidata are the most important lichen species. In the Cariboo Zone the Agropyro - Balsamorhizetum sagittatae appears to be developed only on coarse textured, sandy s o i l s , where water i s available in the lower horizons. It has a history of burning as judged by the f i r e scars on trees in close proximity to sampled plots. This may effect the distribution of the association as light burning has been reported to increase vegetative reproduction of Balsamorhiza sagittata (Brayshaw 1955) . The association also has a history of moderate grazing which does not appear to have altered i t s structure. Fig. 12. The Agropyro - Balsamorhizetum sagittatae showing the characteristic dominance of Balsamorhiza sagittata and Agropyron spicatum. The association i s developed in a gully protected by continuous forest. Fig. 13. The Stipetum richardsonii showing the scattered occurrence of Pinus contorta and the proximity of continuous forest. The herb layer (C) i s dominated by Stipa richardsonii which forms almost closed stands. 107 4. Stipetum richardsonii (ref. Tables; 39, 40, 41, 42, 83, and Fig. 13) Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Arabis h o l b o e l l i i Artemisia frigida Erigeron f l a g e l l a r i s Koeleria g r a c i l i s Tragopogon dubius Tortula ruralis Cladonia pocillum Cladonia pyxidata Alliance Characteristic Species Antennaria rosea Aster campestris Astragalus dasyglottis Carex praticola Cerastium arvense Festuca saximontana Juncus balticus Orthocarpus hispidus Poa pratensis Potentilla pennsylvanica Stipa columbiana Association Characteristic Species Astragalus tenellus Carex obtusata Geranium viscosissimum Stipa richardsonii Important Companion Species Pinus contorta Rosa acicularis Erigeron speciosus Bromus anomalus Geum triflorum Brachythecium salebrosum The Stipetum richardsonii i s found at elevations of greater than 3000 feet on the Fraser Plateau. It occurs either on protected slopes or in shallow gu l l i e s . The slope habitats can be divided into three types; in a l l of them the protection i s provided by continuous forest. These are: 108 Table 39 Stipetum r i c h a r d s o n i i P l o t Data Number of P l o t s 1 2 3 4 5 • ' 6 7 P l o t No. 027 026 024 035 021 050 038 P l o t Size (m2 ) 100 100 100 100 100 100 100 Date analyzed 25/7 23/7 22/7 31/7 21/7 12/8 3/8 1967 1967 1967 1967 1967 1967 1967 El e v a t i o n (ft) 3100 3160 3200 3320 3400 3480 3600 L o c a l i t y FP FP FP FP FP FP FP 51°42' 51°43' 5 1 0 4 3 . 51°47' 51°45' 51°47' 51°47' 122°39' 122°38' 122°38' 122°40' 122°42' 122°36' 122°37 Physiography Landform g u l l y R e l i e f shape . . . s t r a i g h t . . . . convex concave convex s t r a i g h t convex Exposure E NW NE SE NE NE E Slope gradient' (°) 4 6 4 4 3 7 2 Layer coverage (%) Bj la y e r 3 - - - - - 8 B 2 l a y e r 1 1 2 3 - - 1 C laye r 100 98 98 92 95 96 98 D laye r 11 75 8 18 14 68 86 P l o t coverage Humus and l i t t e r 100 100 100 96 99 98 98 Mineral s o i l - - - 4 1 2 2 S o i l Hygrotope Trophotope Erosion Drainage Horizon depth (in) A B C n i l ...(subhygric) - submesic - (subxeric)... permesotrophic - eutrophic n i l n i l s l i g h t n i l n i l water n i l 0-5 0-6 0-5 5-12 6-17 5-13 12-27+ 17-30+ 13-26+ . w e l l . 0-5 5-14 14-30+ 0-4 0-7 0-6 4-9 7-16 6-14 9-24+ 16-34+ 14-24+ Parent ma t e r i a l t h i n a e o l i a n deposit over g l a c i a l d r i f t ? 109 Table 40 Stipetum richardsonii Number of Plots 1 2 3 4 5 6 7 Plot No. 027 026 024 035 021 050 038 Plot~Size (m2) 100 100 100 100 100 100 100 Elevation (ft) 3100 3160 3200 3320 3400 3480 3600 sub Avg Species B Layer layer Constancy Significance 1 Pinus contorta 1 3.+ _ _ - - _ _ III 0.4 2 - 3.+ 3.+ 2.+ - - - 1.1 2 Rosa a c i c u l a r i s 2 - 2.+ - 3.+ - - - V 0.9 C Layer 3 Stipa richardsonii 9.7 9.6 9.7 6.2 8.4 8.5 9.6 V 8.3 4 Carex praticola 3.2 3.2 2.1 5.3 4.2 3.1 4.3 V 3.4 5 Cerastium arvense 3.3 3.3 3.2 2.2 3.1 2.1 2.1 V 2.3 6 Anemone multifida 1.+ 2.1 2.+ 4.1 2.2 1.+ 2.1 V 2.0 7 Agropyron subsecundum 2.1 - 3.2 2.1 2.2 2.1 3.1 V 2.0 8 Stipa columbiana - 2.2 2.1 1.1 2.1 4.3 2.2 V 1.9 9 Erigeron speciosus 2.+ 3.1 2.+ - 2.+ 2.+ 2.1 V 1.9 10 Antennaria rosea 2.2 2.2 2.1 2.2 2.3 1.1 2.1 V 1.7 11 Carex obtusata 2.2 2.2 3.2 - 1.+ 2.1 2.2 V 1.7 12 Taraxacum o f f i c i n a l e 1.+ 1.2 3.2 2.+ 2.2 1.+ 1.1 V 1.6 13 Achillea millefolium 2.+ 1.+ 1.1 2.1 1.+ 1.+ 1.+ V 1.4 14 Koeleria g r a c i l i s 1.1 2.1 + .+ 2.1 1.+ 1.1 2.1 V 1.4 15 Aster campestris 1- + 1.1 1.+ 1.1 2.1 2.1 1.1 V 1.3 16 Artemisia f r i g i d a + .+ 1.+ + .+ 1.+ 2.1 1.+ 2.2 V 1.1 Rosa a c i c u l a r i s 1.+ 1.+ + .+ 1.+ + .+ 3.+ + .+ 1.1 17 Erigeron f l a g e l l a r i s + .+ 1.+ 1.+ 2.1 1.+ - 1.+ V 0.9 18 Solidago multiradiata 2.1 - 2.1 - 3.2 4.2 3.1 IV 2.0 19 Astragalus dasyglottis + .+ - 2.1 3.2 3.+ - 3.1 IV 1.6 20 Bromus anomalus 2.1 - 3.2 3.1 2.2 - 1.1 IV 1.6 21 P o t e n t i l l a pennsylvanica 1.+ - 2.1 + .+ 3.2 - 1.+ IV 1.1 22 Tragopogon dubius + .+ - + .+ 1.+ 1.+ + .+ - IV 0.5 23 Geum triflorum 2.1 1.+ - - 3.+ 2.1 - III 1.1 24 Agropyron spicatum - 2.2 - 1.+ 3.2 - 1.2 III 1.0 25 Orthocarpus hispidus + .+ - 1.+ - 1.+ 3.1 - III 0.8 26 Astragalus tenellus - 1.1 - 1.1 1.+ 2.1 - III 0.7 27 Geranium viscosissimum + .+ - - 2.2 - - 2.2 III 0.6 Pinus contorta 1.+ 1.+ 1.+ 1.+ - - - 0.6 28 Poa pratensis 1.1 - 1.+ - 2.1 - - III 0.6 29 Astragalus miser - 2.2 - - 4.2 - - II 0.9 30 Agoseris glauca - - - 2.+ - - 2.+ II 0.6 31 Galium boreale - 2.+ - - 2.2 - II 0.6 32 Elymus glaucus - - - - - ' 1.1 2.1 II 0.4 33 Heuchera c y l i n d r i c a 2.1 - - - - - 1.+ II 0.4 34 Lithospermum ruderale -' - - 1.1 - - 2.1 II 0.4 35 Zygadenus gramineus - - - - 1.+ - 1.+ II 0.4 36 Festuca saximontana - - - 1.2 1.1 - - II 0.3 37 Chenopodium leptophyllum - - - + .+ + .+ - - II 0.1 38 Eriogonum heracleoides + .+ - + .+ - - - - II . 0.1 39 Lomatium macrocarpum - - - - + .+ + .+ - II 0.1 40 Silene scouleri - - + .+ + .+ - - - 1 1 0.1 D Layer (Bryophytes) 41 Brachythecium salebrosum 4.3 8.7 3.2 4.3 3.2 7.3 8.7 v 5.3 42 Tortula ruralis. - 2.1 3.2 3.2 5.3 3.2 3.2 V 2.7 43 Polytrichum juniperinum 2.1 2.1 - 1.+ - - 4.3 III 1.3 4 4 Ceratodon purpureus - - 2.1 - 2.1 1.+ 2.2 III 1.0 45 Eurhynchium pulchellum 1.1 1.1 - 1.1 - 1.1 - III 0.6 (Lichens) 46 Cladonia pocillum 3.2 3.3 2.2 4.2 2.1 3.1 2.1 V 2.7 47 Peltigera canina var. rufescens 1.1 3.2 3.2 2.1 1.1 3.1 3.2 V 2.3 4 8 Cladonia pyxidata - — ~ 2.2 - 3.2 II 0.7 TOTAL SPECIES ( i n c l . sporadics) 33 28 34 39 38 35 34 Sporadic species B Layer 49 Amelanchier a l n i f o l i a C Layer 50 Arabis h o l b o e l l i i 51 C a s t i l l e j a miniata 52 Danthonia spicata 53 Juncus balticus 54 Lathyrus ochroleucus 55 Poa i n t e r i o r 56 Sedum stenopetalum 026(2.+) 035(1.+) 050(1.+) 021(1.1) 021(3.1) 035(+.+) 024(1.+) 035(+.+) 57 Sisyrinchium sarmentosum 58 V i c i a americana D Layer 59 Hedwigia c i l i a t a 60 Hypnum revolutum 61 Drepanocladus uncinatus 62 Cladonia cariosa 63 Cladonia chlorophaea 64 Peltigera lepidophora 65 Peltigera malacea 024(1.+) 027(+.+) 035(1.+) 050(1.1) 050(1.1) 050(1.1) 050(2.1) 035(2.1) 038(2.2) 110 (1) Habitats which occur on the edge of continuous exposed grassland slopes next to the forest border. These are the most common habitats of the Stipetum richardsonii. (2) Habitats which are park-like openings in the continuous forest. (3) Habitats on open sloping ridges bordered by gullies containing forest. The gully habitats extend downslope from forested ridges and dissect the exposed slopes occupied by the Antennario - Poetum secundae. Thus the Stipetum richardsonii i s always in close proximity to the continuous forest and i s regarded as a forest boundary association. Because of i t s topographic position the effect of wind i s negligible in this association which results i n a deep snow accumulation. This i s believed to be an important source of available moisture at the beginning of the growing season. The Stipetum richardsonii i s non-specific with reference to slope exposure and occurs on gentle slopes with gradients ranging from 2° to 7°. The surface topography varies from concave to convex. Generally, there i s no evidence of surface erosion except for the gully habitats where slight water erosion may occur. The s o i l surface i s covered by a thick l i t t e r layer ranging in extent from 96% to 100% of the available surface area. This l i t t e r may substantially reduce moisture loss by evaporation from the s o i l surface as well as increase the surface moisture retention. The soils are well drained and appear to benefit from temporary seepage and runoff. The hygrotope of the Stipetum richardsonii i s considered to vary from subhygric for short periods in the spring following snow melt, to submesic for most of the growing season, and then be reduced to subxeric for a short period in the late summer. The s o i l has an A,B,C, horizon sequence and i s developed from a parent material of thin aeolian deposits overlying g l a c i a l d r i f t . Although, in plots 027, 026, 050, the parent material may be only g l a c i a l d r i f t as the textural I l l difference between the surface and subsurface horizons is small. The A horizon i s dark brown in color and varies i n thickness from four inches to seven inches. The B horizon is lighter in colour with a thickness of five to 11 inches and overlies a light coloured C horizon which appears to be cemented, possibly by calcium. The C horizon also shows a strong efferve-scence with hydrochloric acid, indicating the presence of carbonates, probably calcium carbonate. The texture of the sampled A horizons ranged from sandy loams to s i l t loams with sandy loams being the most prevalent. Coarse fragments are generally absent from the A horizon except for three plots i n which gravels were found. In the lower horizons there i s an increase i n clay content over that of the A horizon, with the maximum clay concentration present i n the C horizon. Here, measured clay ranged from 23% to 39%. The B and C horizons contain coarse fragments ranging in size from gravels to stones. The higher clay content and unsorted material of these horizons i s characteristic of the g l a c i a l d r i f t . Texturally the sampled B horizons ranged from sandy loams to clay loams and the sampled C horizons ranged from loams to clay loams. In both horizons loams are the dominant textural class. Plant roots are concentrated in the fine material of the A horizon with a lesser number present in the B horizon. Very few roots reach as low as the cemented C horizon. Exchangeable cations are present in moderate amounts with calcium dominating the exchange complex. The highest amounts of calcium and magnesium are present i n the C horizon suggesting a movement down the p r o f i l e of these cations. Calcium i s also present in relatively high amounts in the A horizon which could be coupled with calcium release form the decomposing organic matter. Percentage carbon and thus organic matter i s highest i n the A horizon and decreases down the p r o f i l e . The C horizon contains no measureable carbon. Table 41 Soil Texture Stipetum richardsonii Number of Plots Plot No. A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments 1 027 2 026 3 024 4 035 5 021 6 050 7 038 SL SL SL L SL SiL L 6 3 7 12 6 3 14 19 47 49 40 45 53 38 75 50 44 48 49 44 48 g. g. None None None g- None L SL L L L CL L 23 17 20 23 16 30 23 34 24 30 33 35 29 37 43 59 50 44 49 41 43 g.c. g.c.s. g.c. g.c. g. g.c.s. g.c. L L L L CL L SiCL 25 23 25 27 33 24 39 33 30 26 30 30 40 44 42 47 49 43 37 36 17 g.c.s. g.c.s. g.c.s. g.c. g.c.s. g.c.s. g.c.s. Number of Plots 1 Plot No. 027 A Horizon c% 7 N% •41 C/N 17.1 P ppm 6.0 Na 1.04 K 1.03 Ca 7.0 Mg 6.0 CEC 38.5 pH 6.9 B Horizon c% 0 N% .07 C/N 0 P ppm 4.0 Na 1.26 K .33 Ca 5.5 Mg 7.1 CEC 12.4 pH 7.3 C Horizon C% 0 N% .03 C/N 0 P ppm 4.0 Na 1.35 K .14 Ca 8.5 Mg 9.9 CEC 11.3 pH 8.3 Table 42 Soil Chemical Analysis Stipetum richardsonii 2 3 4 026 024 035 8.9 6.3 8.7 .74 .42 .31 12.0 15.0 28.1 3.0 6.0 11.0 .83 .96 .10 1.28 1.54 7.05 8.0 5.5 10.0 4.8 4.9 5.8 40.9 25.9 36.7 6.5 6.3 6.7 0 1.0 5.2 .07 .11 .24 0 9.1 21.7 4.0 3.0 4.0 .96 .52 .44 .20 .26 6.41 6.0 4.5 8.0 6.5 6.6 9.7 13.6 15.4 23.5 7.4 7.5 7.6 0 0 0 .03 .06 .08 0 0 0 3.0 2.0 5.0 1.17 .56 .48 .14 .15 .28 8.0 5.5 19.5 6.6 6.6 14.5 18.0 18.3 16.3 8.1 8.4 8.4 113 5 6 7 021 050 038 14.3 34.1 17.5 .83 1.08 .84 17.2 31.6 20.8 12.0 23.0 22.0 .23 .10 .47 .77 2.24 6.41 9.6 15.0 15.0 4.8 7.6 5.9 43.8 98.5 61.7 6.8 7.2 6.8 6.4 3.4 4.0 .51 .09 .14 12.5 37.8 28.6 11.0 12.0 7.0 1.33 .79 .44 .67 1.6 ' 6.56 6.9 6.8 11.0 7.5 11.1 7.5 28.4 26.3 31.8 6.8 7.6 7.6 0 0 0 .06 .02 .08 0 0 0 9.0 8.0 5.0 1.29 1.69 .48 .15 .15 .28 2.3 15.0 19.5 6.5 9.7 14.5 12.9 12.0 16 ."3 8.2 8.1 8.4 114 Similarly total phosphorus, cation exchange capacity and exchangeable potassium are highest i n the A horizon and decrease with depth. The carbon:nitrogen ratios are generally low suggesting that nitrogen i s available for higher plants. The nitrogen content i s highest i n the A horizon and decreases to trace amounts in the C horizon. The reaction of the A horizon i s circumneutral with measured pH values ranging from 6.3 to 7.2. The s o i l reaction becomes more alkaline with depth and pH values for the C horizon range from 8.1 to 8.4. This alkaline reaction i s probably due to the higher concentration of basic cations. The Stipetum richardsonii i s considered to be permesotrophic to eutrophic. The soils of this association are c l a s s i f i e d as Orthic Dark Brown Chernozems. Structurally the Stipetum richardsonii consists of four vegetation layers. The B^ layer was present only in two plots and the B 2 has a percentage cover of only 1% to 3%. Thus the shrub layers are considered to be poorly developed. The C layer i s very well developed and has a percentage cover ranging from 92% to 100%. The D layer i s variably developed and ranges in cover form 8% to 86%. Pinus contorta and Rosa acicularis are the only species present in the B^ and B2 layers. Pinus contorta i s thought to be here because the snow accumulation and generally moist habitat w i l l favour the establishment of tree seedlings. Stipa richardsonii dominates the C layer with an average species significance of 8.3. It i s largely responsible for the physiognomy and cover of this layer. Carex praticola i s a constant subdominant with an average species significance of 3.4. Both species appear to favour moist habitats. Constant nondominants indicative of moist conditions include: Anemone multifida, Agropyron subsecundum, Erigeron speciosus, Rosa acicularis, Stipa columbiana 115 and Carex obtusata. Antennaria rosea, Koeleria g r a c i l i s , Aster campestris, Artemisia f r i g i d a and Astragalus dasyglottis are constant grassland species occurring with low species significances. Non-constant species considered as indicative of the moist habitat conditions of this association are: Poa  pratensis, Solidago multiradiata, Bromus anomalus, Geum triflorum and Orthocarpus  hispidus. Erigeron f l a g e l l a r i s , Potentilla pennsylvanica and Agropyron  spicatum occur with low species significance i n the more exposed parts of the association. Astragalus tenellus and Geranium viscosissimum, both occurring with low species significance, are considered as characteristic species because of their preference for this association. The D layer i s composed largely of one species, Brachythecium  salebrosum which i s present with an average species significance of 5.3. This species forms a very extensive mat under the Stipa richardsonii l i t t e r and i s indicative of the moist s o i l surface. Tortula r u r a l i s , Cladonia pocillum, which are more characteristic of exposed dry habitats, are present here, with low species significance. The only other constant species of this layer i s Peltigera canina var. rufescens. The Stipetum richardsonii has a history of only light grazing i n which certain plants are selected. Agropyron spicatum and Rosa acicularis appear to be heavily grazed. Stipa richardsonii, however, i s hardly grazed at a l l possibly because of i t s sharply awned f r u i t s . Parts of this association also appear to have a history involving f i r e as judged by the presence of charcoal i n the s o i l profiles. The occurrence of Pinus contorta here, may be / related to this f i r e history, as Pinus contorta regenerates quickly in suitable habitats following f i r e . Agropyrion spicati 1. Agropyretum spicati (ref. Tables; 43, 44, 45, 46, 83, and Fig. 14) 116 Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Artemisia frigida Arabis h o l b o e l l i i Koeleria g r a c i l i s Tragopogon dubius Tortula ruralis Cladonia pocillum Cladonia pyxidata Alliance Characteristic Species Lithospermum ruderale Lomatium macrocarpum Calochortus macrocarpus Opuntia f r a g i l i s Diploschistes canadensis Physcia muscigena Association Characteristic Species Crepis atrabarba Heuchera cylindrica Linum lewisii Zygadenus gramineus Peltigera lepidophora Important Companion Species Artemisia campestris The Agropyretum spicati occurs at elevations below 3000 feet on the Fraser Plateau and thus i s restricted to the major river valleys. It i s formed on the steep sides of water eroded ravines, on exposed slopes and on ridges. The sampled plots were located on slopes with northerly exposures and gradients ranging from 23° to 4 3 0 . The northerly exposures of these habitats cause them to be microclimaticaly cooler and more moist than the neighbouring habitats. They also remain snow covered longer in the spring (see page246 ). The surface topography ranges from straight to convex. So i l surface i s covered by a thick layer of Agropyron spicatum l i t t e r which w i l l aid in s o i l moisture conservation by decreasing surface evaporation. However, some mineral s o i l was exposed in a l l plots sampled. The hygrotope of this association is rated as subxeric. Table 43 Agropyretum spicati Plot Data Number of Plots 1 2 3 4 5 Plot No. 087 060 064 043 031 Plot Size (m2) 100 100 100 100 100 Date analyzed 24/7 6/6 16/6 8/8 29/7 1968 1968 1968 1967 1967 Elevation (ft) 1800 2120 2200 2210 2400 Locality FP FP FP FP FP 51°49' 51°48* 51°50' 51°48' 51°50' 122°33' 122°33' 122°32' 122°30" 122°32" Physiography Landform side of exposed ravine slope Relief shape straight convex concave straight convex NW N NW NW NW Slope gradient (°) 43 23 28 36 27 Layer coverage (%) A3 layer - 12 - - -B2 layer - 2 1 - -C layer 88 84 88 91 70 D layer 40 39 35 32 3 Plot coverage (%) Humus and l i t t e r 94 96 97 94 76 Mineral s o i l 6 4 3 6 24 Soil Hygrotope .......... ......... Trophotope ......... . eutrophic Erosion slight water Drainage .......... ......... Horizon depth (in) A 0-8 0-7 0-8 0-13 0-5 B 8-14 7-19 8-19 13-24 5-10 C 14-34+ 19-36+ 19-26+ 24-37+ 10-24+ Parent material aeolian deposit aeolian - • • aeolian deposit over over gla- deposit gl a c i a l d r i f t c i a l d r i f t 118 Table 44 Agropyretum s p i c a t i Number of Plots Plot No. Plot Size (m2) Elevation (ft) B Laver 1 2 3 4 5 087 060 064 043 031 100 100 100 100 100 1800 2120 2200 2210 2400 sub laver Constancy Avg Species S i g n i f i c a n c e 1 Artemisia t r i d e n t a t a 2 - 2.1 2.+ - - II 0.8 C Laver 2 Agropyron spicatum 8.2 8.4 8.3 9.7 8.6 V 8.2 3 Artemisia f r i g i d a 2.1 3.2 3.1 3.2 3.2 V 2.8 4 Heuchera c y l i n d r i c a 2.1 4.2 4.2 1.+ 2.1 V 2.7 5 Lomatium macrocarpum 2.1 3.+ 3.+ 2.+ 3.+ V 2.6 6 Zygadenus gramineus 2.+ 2.+ 1.+ 1.+ 2.+ V 1.6 7 Arabis h o l b o e l l i i 1.1 1.+ 1.1 1.+ 1.+ V 1.0 8 Taraxacum o f f i c i n a l e + .+ + .+ 2.+ 1„+ 1.+ V 1.0 9 Tragopogon dubius + .+ 1.+ 1.+ + .+ 2.+ V 1.0 10 K o e l e r i a g r a c i l i s - 3.1 2.1 3.3 4.3 IV 3.0 11 Solidago multiradiata 3.+ 1.+ 2.1 2.2 - IV 1.6 12 Crepis atrabarba - 2.+ 2.+ 2.1 1.+ IV 1.4 13 Lithospermum ruderale - 1.1 2.1 1.1 2.1 IV 1.0 14 Antennaria umbrinella 3.2 5.2 4.3 - - III 2.4 15 Artemisia campestris - - 2.1 2.1 2.+ III 1.2 16 Linum l e w i s i i - - 1.1 + .+ 1.+ III 0.5 17 Antennaria rosea - - 1.1 3.2 - II 1.0 18 Geum t r i f l o r u m 2.1 2.2 - - - II 0.8 19 Opuntia f r a g i l i s - - - 2.1 3.2 II 0.8 20 Sedum stenopetalum 1.+ 1.+ - - - II 0.4 21 Calochortus macrocarpus 2.+ - - - II 0.4 22 A c h i l l e a m i l l e f o l i u m 1.+ + .+ - - - II 0.3 D Laver 23 S e l a g i n e l l a densa 4.2 - 2.2 - II 1.2 (Bryophytes) 24 T o r t u l a r u r a l i s 4.3 3.2 4.2 3.2 2.2 V 3.2 25 Ceratodon purpureus 3.2 2.1 1.1 2.1 1.+ V 1.8 26 Eurhynchium pulchellum 4.1 - 3.2 + .+ - III 2.2 (Lichens) 27 Cladonia pocillum 4.2 5.3 5.3 5.2 2.1 V 4.2 28 D i p l o s c h i s t e s canadensis 2.1 2.1 2.1 2.1 3.1 V 2.2 29 P e l t i g e r a canina var. rufescens 3.2 3.2 - 2.2 - I I I 1.6 30 P e l t i g e r a lepidophora - 2.2 2.1 2.2 - III 1.2 31 Cladonia pyxidata - 4.2 4.2 - - II 1.6 32 Cladonia chlorophaea 3.2 2.2 - - - II 1.0 33 P e l t i g e r a malacea 2.2 3.1 - - - II 1.0 34 Ochrolechia u p s a l i e n s i s 1.1 1.+ - - II 0.4 TOTAL SPECIES ( i n c l . sporadics) 30 28 27 25 21 Sporadic species A Layer 35 Pseudotsuga menziesii C Laver 36 Agoseris glauca 37 A l l i u m cernuum 38 Antennaria dimorpha 39 Chenopodium leptophyHum 40 Chrysothamnus nauseosus 060(3. + ) 064(1.+) 087 (2. + ) 031(2.1) 064(+. + ) 043 (2.. + ) 41 Erigeron speciosus 42 Poa secunda 43 Saxifraga o c c i d e n t a l i s 44 Woodsia oregana D Layer 45 Amblystegium serpens 46 Physcia muscigena 47 Thrombium epigaeum 060(2. + ) 031(1.1) 087(2.+) 087 (1.1) 087(1.+) 087(2.+) 031(1.+) 119 The s o i l has an A,B,C, horizon sequence and i s formed from a parent material of aeolian deposits overlying g l a c i a l d r i f t . Because of the high percentage of sand in the lower horizons, the d r i f t may actually be outwash material. Plot 060, however, appears to be formed only on aeolian material as no g l a c i a l d r i f t was encountered to a depth of 40 inches. The A horizon, which varies in thickness from five to 13 inches, i s well melanized and contains no coarse particles. Texturally the sampled A horizons are cl a s s i f i e d as s i l t y loams or sandy loams. The B horizon has a thickness ranging from five inches to 12 inches and i s lighter i n colour than the A horizon because of a lower organic matter accumulation. Sand sized particles are the dominant fraction in sampled B horizons, which range texturally from sands to sandy clay loams. Coarse fragments were present in three samples. The C horizon i s very light coloured and generally devoid of organic matter. It effervesces strongly with hydrochloric acid indicating the presence of carbonates, probably calcium carbonate. Sampled C horizons were composed largely of sand sized particles and are c l a s s i f i e d as sands, sandy loams or s i l t loams. Gravels, cobbles and stones were present i n a l l profiles except 060. The coarse fragments present are mostly basalts and other lavas; these w i l l provide an alkaline parent material. Serpentine was also present and this w i l l release magnesium on weathering which may account for the high magnesium values of the s o i l . Cation exchange capacity i s high in the A horizon because of the relatively large amounts of incorporated organic matter (measured carbon ranges from 4.6% to 13.1%). Cation exchange capacity decreases with depth corresponding to the increased coarseness of the texture of the lower horizons. Exchangeable cations are present in high amounts with calcium dominating the exchange complex. The highest concentrations of calcium and magnesium occur i n the C layer indicating a movement of these elements down the p r o f i l e . The high calcium concentrations Number of Plots Plot No. A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments Table 45 Soil Texture Agropyretum spicati 1 087 2 060 3 064 4 043 5 031 SL SiL SL SiL SL 2 10 2 4 3 35 53 50 51 45 63 37 48 45 52 * • None S SL SL SL SCL 1 18 3 8 23 13 32 47 38 25 86 51 50 55 52 gravels None None g. g.c. S SiL SL SL SL 1 13 6 11 14 4 54 24 19 13 96 32 70 70 73 g.c.s. None g. g.c. g.c.s. to o 121 Number of Plots Plot No. Table 46 Soil Chemical Analysis Agropyretum spicati 1 087 2 060 3 064 4 043 5 031 A Horizon C% N% C/N P ppm Na K Ca Mg CEC PH 13.1 .42 31.2 26.0 .33 .29 12.8 4.8 57.6 7.4 11.8 .53 22. 13. ,3 .0 .12 .61 8.8 5.7 43.6 7.0 4.7 .29 16.2 7.0 .12 .45 7.2 4.7 12.9 6.9 22 12 6 11 4 41 7 .4 .28 .9 .0 .13 .41 ,0 .3 .6 .3 4.6 .26 17.7 9.0 1.30 1.03 6.5 4.9 16.3 7.7 B Horizon C% N%' C/N P ppm Na K Ca Mg CEC PH 1.3 .17 7.6 2.0 .28 .22 11.9 4.1 4.9 8.2 12 15 6 10 5 19 7 ,7 ,30 ,3 .0 .61 .37 .1 ,9 ,7 .8 3.1 .42 7.4 6.0 .17 .21 11.4 6.3 16.1 7.7 2.1 .09 23.3 8.0 .39 ••. 23 17. 5. 22. 8. 16 8 1 9 7 12 7 .7 .16 ,9 ,0 .22 .29 .0 .8 .2 .9 C Horizon C% 0 2.3 0 0 0 N% .05 .15 .08 .03 .06 C/N 0 15.3 0 0 0 P ppm 3.0 5.0 4.0 5.0 3.0 Na .41 4.20 .57 .57 1.61 K .17 .61 .18 .25 .17 Ca 15.8 11.8 19.6 21.5 9.0 Mg 4.2 7.1 7.5 9.8 10.2 CEC 3.4 18.3 5.0 8.9 6.8 pH 8.3 8.4 8.4 8.5 8.4 122 support the idea that the carbonates present are probably calcium carbonate. Exchangeable sodium i s present i n low amounts so probably w i l l not interfere with the exchange complex. The highest concentration of exchangeable potassium i s in the A horizon and this cation decreases in amount with depth. Similarly the concentrations of total phosphorus and total nitrogen decrease from the surface down the p r o f i l e . A l l of these elements appear to be closely correlated with the amount of organic matter i n the s o i l which also decreases with depth (organic matter i s estimated from the measured carbon). The carbon:nitrogen ratios are sufficiently high in some of the sampled A horizons to suggest that a competition for nitrogen between the microflora and the higher plants may occur. However, carbon:nitrogen ratios in the B horizons are generally very low, thus nitrogen i s probably available for higher plants. The s o i l reaction i s neutral to slig h t l y alkaline in the A horizon with measured pH values ranging from 6.9 to 7.7. Alkalinity increases with depth and pH values of the C horizon range form 8.3 to 8.5. The higher pH values of the C horizon are most lik e l y due to the higher concentrations of basic cations, particularly calcium. These soil s are considered to be eutrophic because of the high ava i l a b i l i t y of nutrients and the favourable pH. The soils are cl a s s i f i e d as Orthic Brown Chernozems. A study of the root distribution showed that roots were concentrated in the A and B horizons with only a few roots extending into the C horizon. The Agropyretum spicati generally consists of two vegetation layers, a well developed C layer and a moderately well developed D layer. However, occasionally a poorly developed B layer or even an A^ layer may be present. In sampled plots, the C layer had a percentage cover of 70% to 91% and the D layer a cover of 3% to 40%. The A layer, when present, (plot 060) i s composed of Pseudotsuga  menziesii which occurs with low species significance. Generally P. menziesii 123 grows poorly in these dry habitats with fine textured s o i l s . The B layer, present only in two plots, was composed solely of Artemisia tridentata with very low species significance. Agropyron spicatum dominates this association with an average species significance of 8.2, and i s largely responsible for the physiognomy and structure of the C layer. Heuchera cylindrica, Zygadenus gramineus, Crepis atrabarba and Linum lewisii are considered as characteristic species because of their high preference for this association. Other constant species occurring with low significance include; Artemisia frigida, Lomatium  macrocarpum, Tragopogon dubius, Koeleria g r a c i l i s . Lithospermum ruderale, Artemisia campestris, Opuntia f r a g i l i s , Sedum stenopetalum and Calochortus  macrocarpus a l l occur as non-constants with low significance and are characteristic of the dry exposed habitat. Cladonia pocillum with an average species significance of 4.2 and Tortula ruralis with an average species significance of 3.2 dominate the D layer. Diploschistes candensis and Ceratodon purpureus are the only other constant D layer species. The presence of Eurhynchium pulchellum indicates the moist s o i l surface conditions existing under the l i t t e r layer. Peltigera lepidophora i s the only non-vascular species considered as characteristic for this association. The Agropyretum spicati i s generally very heavily grazed in the Cariboo Zone which i s resulting in a reduction in the area covered by this association. However, on very steep slopes the grazing i s considerably less and here, the association appears to be only moderately grazed. Communities, f l o r i s t i c a l l y very similar to the Agropyretum spica t i , were observed on steep open slopes with southerly exposures in the forested areas. These slopes were always bordered by associations of the Pseudotsugetalia menziesii. None of these communities were sampled in the present study. 124 Pig. 14. The Agropyretum spicati shown here as developed on a steep slope i n near virgin condition. The association i s characterized by an almost complete cover of Agropyron spicatum. Fig. 15. The Agropyro - Artemisietum tridentatae showing the dominance of Artemisia tridentata which averages between three and five feet in height. The association i s developed on a level river terrace on a fine textured regosolic s o i l . Agropyron spicatum and Artemisia frigida dominate the C layer. 125 2. Agropyro (spicati) - Artemisietum tridentatae (ref. Tables; 47, 48, 49, 50, 83, and Fig. 15) Characteristic Combination of Species Agropyron spicatum Arabis h o l b o e l l i i Artemisia frigida Erigeron f l a g e l l a r i s Koeleria g r a c i l i s Tragopogon dubius Tortula ruralis Cladonia pocillum Cladonia pyxidata Alliance Characteristic Species Calochortus macrocarpus Comandra umbellata Lithospermum ruderale Lomatium macrocarpum Opuntia f r a g i l i s Diploschistes canadensis Lecidea decipiens Physcia muscigena Association Characteristic Species Artemisia tridentata Artemisia dracunculus Sisymbrium l o e s e l i i Candelariella v i t e l l i n a Important Companion Species Stipa comata The Agropyro - Artemisietum tridentatae occurs near the bottoms of the major valleys and i s best developed at elevations below 2000 feet. It i s usually formed on gently sloping river terraces located at the base of steep valley slopes. Fine textured s o i l i s constantly deposited on these terraces as a result of wind and water erosion of the slopes above. TheQ association also occurs on steep ravine sides, but i s not as well developed on such sites. The association reaches i t s best development on northerly exposures and Artemisia tridentata was observed to grow only marginally on slopes with southerly exposures. 126 Table 47 Agropyro ( s p i c a t i ) - Artemisietum tr i d e n t a t a e Plot Data Number of Pl o t s P l o t No. P l o t Size (m2) Date analyzed El e v a t i o n (ft) L o c a l i t y Physiography Landform R e l i e f shape Exposure Slope gradient (°) Layer coverage (%) B2 la y e r C layer D l a y e r P l o t coverage (%) Humus and l i t t e r Mineral s o i l Decaying wood S o i l Hygrotope Trophotope Erosion Drainage Sample depth (in) 1 2 3 Parent material 1 2 3 4 5 6 039 040 047 046 041 045 400 400 400 400 400 400 5/8 5/8 10/8 10/8 6/8 9/8 1967 1967 1967 1967 1967 1967 1540 1540 1600 1620 1800 2020 FP FP FP FP FP FP 51°50' 51°50' 51°48' 51°48' 51o49. 51°481 122°34' 122°34' .122°38' 122°38' 122°34' 122°28 r i v e r terrace f l a t n e u t r al 0 59 56 25 66 25 8 NW 2 84 18 5 61 27 12 NE 6 70 66 32 74 23 3 s t r a i g h t N 5 61 38 33 72 25 3 , x e r i c .. eutrophic s l i g h t water ... well ... 0-6 12-18 20-50+ Regosol 0-6 0-6 0-6 12-18 12-18 12-18 25-35+ 20-36+ 22-36+ NW 3 55 71 20 74 22 4 side of ravine NE 33 78 20 5 53 42 5 moderate water 0-6 0-5 12-18 5-18 20-36+ 18-36+ aeolian deposits a e o l i a n deposit over g l a -c i a l d r i f t ! 127 T a b l e 48 Agropyro ( s p i c a t i ) - A r temisietum t r i d e n t a t a e Number of P l o t s P l o t No. P l o t S i z e (m2) E l e v a t i o n ( f t ) 1 039 400 1540 2 040 400 1540 3 047 400 1600 4 046 400 1620 5 041 400 1800 6 045 400 2020 B Layer sub l a y e r Constancy Avg S p e c i e s S i g n i f i c a n c e 1 A r t e m i s i a t r i d e n t a t a 2 8. .4 8 .5 8.5 8 .5 8, .5 9.6 V 8. ,2 2 Chrysothamnus nauseosus 2 - 2 .3 2.3 I I 0. ,7 C Layer 3 K o e l e r i a g r a c i l i s 5, .3 4 .2 5.2 5 .3 5. .2 4.2 V 4 . ,7 4 Agropyron spicatum 3, .2 3 .2 4.2 6 .3 6, .2 5.3 V 4 . ,5 5 A r t e m i s i a f r i g i d a 3, .3 3 .2 3.1 3 .2 3, .1 2.2 V 2. , 8 A r t e m i s i a t r i d e n t a t a 3, .3 2, .2 2.1 2 .2 3, .2 3.3 2. ,5 6 Opuntia f r a g i l i s 3, .2 2.1 3 .2 2. .2 2.1 V 2. ,0 7 Lomatium macrocarpum 2, .3 2 .1 2.+ 2 .1 4, .+ 1.+ V 1. . 8 8 A c h i l l e a m i l l e f o l i u m 2, . 1 2 .2 3.1 2. .1 + .+ V 1. ,4 9 Taraxacum o f f i c i n a l e 2, .2 1 . + 2.+ 1 .1 1. .+ - V 1. ,2 10 S o l i d a g o m u l t i r a d i a t a 3. .1 1 .1 +. + + . + +, . + 1.+ V 0. ,9 11 A r a b i s h o l b o e l l i i +, . + + . + - 1 . + 1. . + + . + V 0. ,6 12 E r i g e r o n f l a g e l l a r i s 3, .2 2 .2 2.1 3 .2 - IV 1. ,7 13 Lithospermum r u d e r a l e 2, .2 2 .2 - +, 1.+ IV 0. ,9 14 A r t e m i s i a dracunc u l u s +, . + + .+ + .+ + . + - IV 0. .3 15 S t i p a comata 5, .3 2 .1 - 3. .2 - I I I 1. .7 16 A n t e n n a r i a r o s e a 2, .2 3.1 2 . + - I I I 1. .2 17 Sisymbrium l o e s e l i i 4 .1 1.+ 3 . + - I I I 0. .8 18 E r i g e r o n compositus 2. , + +. + + . + - I I I 0. .5 19 A g o s e r i s g l a u c a + . + - + . + +, .+ - I I I 0. .3 20 A n t e n n a r i a u m b r i n e l l a 4, .3 - 2. .2 - I I 1. .0 21 Sporobolus c r y p t a n d r u s 3.2 2 .2 - I I 0. •8. 22 A n t e n n a r i a dimorpha 2.1 2 .1 - I I 0. 23 Poa secunda 2.1 2 . 1 - I I 0. .1 24 A n t e n n a r i a n e g l e c t a +. + 1 .+ - I I 0. .3 25 Comandra u m b e l l a t a - 1. , + 1.+ I I 0. .3 26 C r e p i s a t r a b a r b a 1. . + 1 . + - - I I 0. .3 27 E r i g e r o n s p e c i o s u s 1. - 1. - I I 0. .3 28 P o t e n t i l l a p e n n s y l v a n i c a 1 . + - + , + - I I 0. .3 29 Linum l e w i s i i +. + + . + - I I 0. .2 30 Tragopogon dubius 1. . + - +. . + - I I 0. . 2 D Layer (Bryophytes) 31 T o r t u l a r u r a l i s 5, . 3 3 . 2 4.3 4 .3 4 .2 3.1 V 3, .8 32 Ceratodon purpureus 2 .1 2 . 1 1.1 2 . 1 - IV 1, . 2 33 Eurhynchium p u l c h e l l u m 1. .1 1 .1 - - I I 0. .3 (Lichens) 34 C l a d o n i a p o c i l l u m 5. .3 3 .2 5.4 4 . 2 5. .3 3.2 V 4 . 2 35 L e c i d e a d e c i p i e n s 2. .1 1 . + 2.1 2 . 1 1. . + - V 1. . 3 36 C a n d e l ^ r i e l l a v i t e l l i n a 2, . 1 1.1 1 .1 1. . + - IV 0, .8 37 Dermatocarpon hepaticum 4 .+ 4 . + - I I 1. . 3 3 8 Thrombium epigaeum 3.2 3 .2 - I I 1. .2 39 C l a d o n i a chlorophaea - 3 . 1 2 . 1 - I I 0 , .8 40 P e l t i g e r a c a n i n a v a r . r u f e s c e n s 2 .1 2 . 1 - - I I 0. , 7 41 P h y s c i a muscigena - 2 .1 2.1 I I 0, .7 42 C a l o p l a c a s t i l i c i d i o r u m 2.1 1 . 1 - I I 0, . 5 4 3 Collema tenax 1 - 1 . + I I c, , 3 TOTAL SPECIES ( i n c l . s p o r a d i c s ) 35 26 30 31 25 S p o r a d i c s p e c i e s B Layer 44 Symphoricarpos o c c i d e n t a l i s C Layer 45 A r n i c a s o r o r i a 46 A r t e m i s i a campestris 47 A s t r a g a l u s d a s y g l o t t i s 48 C a l o c h o r t u s macrocarpus 49 Carex p r a t i c o l a 50 C r e p i s tectorum 51 Eriogonum h e r a c l e o i d e s 52 Heuchera c y l i n d r i c a 039(+. . + ) 040(3. .3) 53 Poa j u n c i f o l i a 040(2. .2) 54 Poa p r a t e n s i s 047(+. . + ) 55 Zygadenus gramineus 040(+, .+) 040(+. . + ) 039(2. .2) D Layer 039(+. . + ) 039(2. .1) 56 Brachythecium salebrosum 039(2. .1) 039(1. .1) 57 C l a d o n i a p y x i d a t a 045(3 .1) 039(2. . + ) 58 D i p l o s c h i s t e s canadensis 047(3. .2) 041(+. . + ) 59 F u l g e n s i a b r a c t e a t a 045(1. . + ) 128 The s o i l surface of the Agropyro - Artemisietum tridentatae i s covered by a thin layer of l i t t e r which i s mostly composed of leaves and decaying stems of Artemisia tridentata. However, mineral s o i l was exposed in a l l plots sampled, thus evaporation from the s o i l surface i s believed to occur readily. The s o i l i s well drained although moderate surface runoff occurs as there i s evidence of slight water erosion. The association i s rated as xeric. With the exception of plot 045 which was located on a steep slope, the s o i l i s formed from a parent material of aeolian deposits and has no discernible horizonation. In plot 045 the parent material appears to be aeolian deposits overlying g l a c i a l d r i f t and the s o i l has an A,B,C, horizon sequence. The A horizon i s melanized and five inches thick; the B horizon i s lighter coloured and 13 inches thick and the C horizon i s ligh t coloured and appears to be cemented. The lower levels of a l l profiles effervesced with hydrochloric acid indicating the presence of carbonates. The sampled surface horizons vary texturally from sandy loams to s i l t loams with s i l t sized particles being the dominant s o i l fraction. Clay content increases in the second sample (B) and these are cl a s s i f i e d as sandy loams, s i l t s or loams. Clay content i s generally greater s t i l l in the third sample and these range texturally from sandy loams to clay loams. Soil pits were dug to a depth of over forty inches and no coarse particles were found; with the exception of plot 045 which had gravels and cobbles present i n the lower horizons. The s o i l reaction i s neutral to alkaline near the surface and becomes alkaline with depth. Measured pH values at the surface ranged from 7.1 to 8.0 and those of the third sample from 8.2 to 8.6. Exchangeable cations are present in moderately high amounts, with calcium dominating the exchange complex. Calcium and magnesium both increase in 129 amounts with depth indicating that some enrichment of the lower horizons i s occurring. The higher calcium concentrations iri the lower horizons may in part account for the higher alkalinity of the s o i l . Exchangeable sodium i s present in low amounts so most l i k e l y w i l l not alter the exchange complex. The concentration of exchangeable potassium i s high in the surface sample with a range of 6.1 meg/100 g to 6.7 meg/100 g, and decreases with depth. This suggests that the l i t t e r of Artemisia tridentata contains a high concentration of potassium. It appears that some organic matter i s being incorporated into the s o i l , as estimated from the presence of carbon in measureable amounts. The percentage of measured carbon i s highest in surface horizons and decreases down the p r o f i l e . Similarly, available phosphorus which i s present i n low amounts decreases with depth. Total nitrogen i s present i n low to moderate amounts and decreases down the pr o f i l e . The carbon:nitrogen ratios are generally low indicating that the organic matter i n the s o i l contains sufficient nitrogen for decomposition, thus nitrogen w i l l be available for higher plants. The cation exchange capacity i s high in the surface horizon and corresponds to the higher amounts of organic matter present. It decreases only slightly with depth because of the fine textured s o i l s . Based on the available chemical data this association i s considered to be eutrophic. With the exception of plot 045 the so i l s are cla s s i f i e d as Orthic Regosols because of their lack of horizon development. Plot 045 i s c l a s s i f i e d as an Orthic Brown Chernozem. The deposition of s o i l from the slopes above i s believed to be helping to maintain the soils in a regosolic condition. Three vegetation layers are present in the Agropyro - Artemisietum tridentatae. The shrub (B2 ) layer has a percentage cover ranging from 55% to 78% under which i s developed a herb (C) layer with a coverage ranging from 18% to 20%. The Bryophyte and lichen layer i s moderately well developed Table 49 Soil Texture Agropyro (spicati) - Artemisietum tridentatae Number of Plots 1 2 3 4 5 6 Plot No. 039 040 047 046 041 045 Sample 1 Textural class SL SiL SiL SL SiL SL Clay (%) 6 12 8 7 7 6 S i l t (%) 45 61 53 47 51 32 Sand (%) 49 27 39 46 42 62 V^ r L>4> ^ »7_> "w ••- W M l l l W 11 U *J Sample 2 Textural class SL SiL L L SiL SL Clay (%) 9 9 20 24 14 8 S i l t (%) 44 59 45 46 52 24 Sand (%) 47 32 35 30 34 68 Coarse fragments None None None None None g. Sample 3 Textural class SL SiL L CL SiL SL Clay (%) 10 25 26 31 19 9 S i l t (%) . 46 61 40 40 57 30 Sand (%) 44 14 34 29 24 Coarse fragments None None None None None g.c.s. ° 131 Table 50 Soil Chemical Analysis Agropyro (spicati) - Artemisietum tridentatae Number of Plots 1 2 3 4 5 6 Plot No. 039 040 047 046 041 045 Sample 1 C% 4.8 7.0 13.5 10.6 16.4 7.1 N% .17 .28 .69 .63 .84 .41 C/N .28.2 25.0 19.6 16.8 19.5 17.3 P ppm 5.0 6.0 7.0 15.0 8.0 17.0 Na .12 .44 .27 .13 .34 .13 K 6.1 6.41 6.4 6.7 6.33 6.4 Ca 11.0 18.0 11.5 11.0 9.0 9.5 Mg 2.25 6.0 4.7 4.8 5.2 2.3 CEC 28.6 22.8 48.0 33.7 52.8 24.8 pH 8.0 7.8 7.1 7.5 7.3 8.0 Sample 2 C% 3.6 9.4 6.1 3.4 1.9 3.9 N% .21 .26 .29 .17 .07 .28 C/N 17.1 36.2 21.0 20.0 27.1 13.9 P ppm 5.0 6.0 8.0 8.0 5.0 13.0 Na .67 5.0 .53 .96 1.10 .13 K 8.2 6.6 .28 .26 6.13 .34 Ca 16.5 6.0 21.5 19.0 7.5 16.5 Mg 6.92 10.3 6.7 9.8 9.6 3.3 CEC 24.3 45.3 32.6 28.5 27.6 18.4 pH 8.4 8.0 8.1 8.3 8.0 7.9 Sample 3 C% 0 2.3 3.4 0 0 0 N% .05 .13 .23 .04 .03 .11 C/N 0 17.7 14.8 0 0 0 P ppm 2.0 5.0 5.0 9.0 4.0 3.0 Na 1.4 1.4 1.41 1.8 1.99 .42 K 5.4 6.7 .34 .38 5.89 .23 Ca 16.5 10.0 22.5 17.5 22.5 16.0 Mg 11.2 9.3 9.8 9.2 15.9 4.8 CEC 16.5 21.7 23.7 19.3 20.4 8.9 pH 8.4 8.6 8.4 8.5 8.3 8.2 132 with a percentage cover ranging from 5% to 33%. The association i s dominated by Artemisia tridentata with an average species significance of 8.2. The only other shrub species present i s Chrysothamnus nauseosus. These xerophytic shrub species which are characteristic of semi-arid climates (annual precipitation from five to seven inches), are established in subhumid regions, such as the Cariboo Zone only on fine textured s i l t - c l a y s o i l s . In these soi l s a substantial part of the moisture i s held i n hygroscopic condition and i s unavailable to plants. Because of this such sites are essentially drier than would be anticipated in a subhumid climate. The C layer i s dominated by Koeleria g r a c i l i s and Agropyron spicatum with average species significance of 4.7 and 4.5 respectively. Other constant species includes Artemisia f r i g i d a , Opuntia f r a g i l i s , Lomatium macrocarpum, Solidago multiradiata and Arabis h o l b o e l l i i . Artemisia dracunculus, with a constancy of class IV, and Sisymbrium l o e s e l l i i with a constancy of class III, are considered as characteristic species because of their high preference for this association. Other non constant species important i n the definition of the Agropyro - Artemisietum tridentatae are: Erigeron f l a g e l l a r i s , Lithospermum ruderale, Stipa comata, Sporobolus cryptandrus, Comandra umbellata and Linum l e w i s i i . In this dry habitat lichens compose more of the structure of the D layer than do bryophytes. The most important bryophytes are Tortula ruralis with an average species significance of 3.8 and Ceratodon purpureus with an average species significance of 1.2. Eurhynchium pulchellum and Brachythecium  salebrosum occur with low constancy near the base of Artemisia tridentata plants where more moisture i s available. Cladonia pocillum and Lecidea decipiens are the dominant lichens 133 with average species significances of 4.2 and 1.3 respectively. Candelariella  v i t e l l i n a , Dermatocarpon hepaticum, Thrombium epigaeum, Cladonia chlorophaea, Physcia muscigena, and Diploschistes canadensis occur with low constancy but are indicative of the xeric habitat. The regularly occurring species of this association form a group which i s characteristic of xeric, alkaline habitats as well as fine textured s o i l s . The Agropyro - Artemisietum tridentatae has a history of moderate to severe grazing as i t forms a major part of the spring cattle range. Grazing may actually favour the development of this association. Through grazing, a reduction i n the density of shallow rooting grass species w i l l occur, which . in turn w i l l allow some moisture to penetrate into the s o i l and become available to deeply rooting shrub species, like Artemisia tridentata. 3. Opuntio (fragilis) - Stipetum comatae (ref. Tables; 51, 52, 53, 54, 83, and Fig. 16) Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Artemisia f r i g i d a Erigeron f l a g e l l a r i s Arabis h o l b o e l l i i Koeleria g r a c i l i s Tragopogon dubius Tortula ruralis Cladonia pocillum Alliance Characteristic Species Lomatium macrocarpum Comandra umbellata Calochortus macrocarpus Opuntia f r a g i l i s Lecidea decipiens Diploschistes canadensis Physcia muscigena 134 Association Characteristic Species Stipa comata Sporobolus cryptandrus Thrombium epigaeum The Opuntio - Stipetum comatae i s found at low elevations on the Fraser Plateau and reaches i t s best development near the bottoms of the major valleys. Here, a warm climate and long growing season prevail. The association occurs on gently sloping terraces with south or southwest exposures. Measured slope angles ranged from 2P to 130. These terraces are located at the base of steep slopes on which the Agropyretum spicati i s developed and appear to benefit from deposition of s o i l eroded by wind and water from the steep slopes. The terraces are greatly dissected by water formed ravines and thus the habitat of the Opuntio - Stipetum comatae has the appear-ance of sloping ridges. The slopes are snow free earlier than any other areas; sometimes being bare as early as February 15. Thus moisture loss by evaporation may begin early i n the season. The s o i l surface i s covered by an extensive but very thin layer of l i t t e r which does l i t t l e to prevent moisture loss. Evaporation and surface drying in some areas i s severe enough in the summer to cause cracking of the s o i l surface. The s o i l i s well drained and very l i t t l e surface runoff occurs. The hygrotope of this association i s considered to be very xeric. Plant roots are matted i n the top 15 inches of the s o i l and very few roots were found at lower depths. This surface root concentration could be a response to water penetration, as moisture w i l l seldom be present in the lower horizons. The s o i l i s developed from a parent material of aeolian material overlying gl a c i a l d r i f t with the exception of plot 062 in which the parent material appears to be only aeolian deposits. In the profiles of plots 062 and 044 no horizon development was apparent whereas in the remaining profiles Table 5 1 Qpuntio (fragilis) - Stipetum comatae Plot Data Number of Plots 1 2 3 4 5 Plot No. 062 044 059 032 042 Plot Size (m2) 100 100 100 100 100 Date analyzed 10/6 8/8 8/9 29/7 8/8 1968 1967 1967 1967 1967 Elevation (ft) 1700 1920 2000 2150 2260 Locality FP FP FP FP FP 51°50' 51°50' 51°50' 51°50' 51°50' 122°31' 122°30' 122°30' 122°32' 122°30' Physiography Landform river terrace exposed Relief shape straight straight convex straight straight Exposure SW S SW SW SW Slope gradient (°) 2 4 4 13 13 Layer coverage (%) B2 layer 5 - - 3 -C layer 81 88 84 88 82 D layer 12 5 15 4 14 Plot coverage (%) Humus and l i t t e r 85 90" 91 90 85 Mineral s o i l 15 10 9 10 15 Soil Hygrotope Trophotope eutrophic Erosion slight slight slight water n i l water water n i l Drainage Horizon depth (in) Regosol Regosol A 0-6 0-18 0-7 0-7 0-8 B 6-12 18-23 7-17 7-15 8-17 C 24-30+ 23-30+ 16-30+ 15-27+ 17-28+ Parent material aeolian deposit ..aeolian deposit over glacial d r i f t 136 Table 52 Opuntio ( f r a g i l i s ) - Stipetum comatae Number of Plots 1 2 3 4 5 Pl o t No. 062 044 059 032 042 Pl o t Size (m2) 100 100 100 100 100 El e v a t i o n (ft) 1700 1920 2000 2150 2260 Avg Species C Layer Constancy S i g n i f i c a n c e 1 S t i p a comata 7.2 8.5 8.4 8.5 8.4 V 7.8 2 Sporobolus cryptandrus 6.1 3.1 4.2 3.2 5.2 V 4.2 3 Artemisia f r i g i d a 1.1 5.2 5.2 4.2 3.1 V 3.6 4 Opuntia f r a g i l i s 4.2 3.1 4.3 3.2 4.2 V 3.6 5 K o e l e r i a g r a c i l i s 2.1 3.2 3.1 2.1 2.1 V 2.4 6 Lomatium macrocarpum 3.+ 1.+ 2.+ 3.1 3.+ V 2.4 7 Tragopogon dubius 2.+ 1.+ + .+ 1.+ + .+ V 1.0 8 Arabis h o l b o e l l i i + .+ 1.+ 1.+ + .+ + .+ V 0.7 9 Comandra umbellata - 1.1 1.+ 3.2 2.1 IV 1.4 10 Chenopodium leptophyllum 2.+ + .+ - 1.+ - III 0.7 11 Artemisia campestris - - 2.1 2.1 - II 0.8 12 Chrysothamnus nauseosus - - - 1.+ 1.+ II 0.4 13 P o t e n t i l l a pennsylvanica 1.+ + .+ - - - II 0.3 14 Taraxacum o f f i c i n a l e + .+ + .+ - - - II 0.2 IS Cirsium undulatum + .+ + .+ - - - II 0.2 D Layer (Bryophytes) 16 T o r t u l a r u r a l i s 2.1 3.1 3.1 2.2 3.2 V 2.6 (Lichens) 17 Cladonia pocillum 4.1 3.2 4.2 3.2 3.2 V 3.4 18 Lecidea decipiens 3.1 2.1 2.1 3.1 2.1 V 2.4 19 Thrombium epigaeum 2.1 2.1 1.1 2.1 3.1 V 2.0 20 D i p l o s c h i s t e s canadensis 2.1 2.1 3.1 - 2.1 IV 1.8 21 Physcia muscigena 3.1 3.1 - - - II 1.2 22 Dermatocarpon hepaticum 2.1 1.1 - - - II 0.6 23 Fulgensia bracteata 2.1 1.1 II 0.6 TOTAL SPECIES ( i n c l . sporadics) 27 24 16 19 17 Sporadic species B Layer 24 Artemisia t r i d e n t a t a C Layer 25 Agropyron spicatum 26 Agoseris glauca 27 Androsace s e p t e n t r i o n a l i s 28 Calochortus macrocarpus 29 Crepis atrabarba 30 Descurainea pinnata 31 Erigeron compositus 062(3.+) 032(2.1) 032(1.1) 059(1.+) 044(3.1) 044(+.+) 062(1.+) 032(1.1) 32 Erigeron f l a g e l l a r i s 33 Lappula redowskii 34 Lepidium densiflorum 35 Lepidium virginicum 36 Zygadenus gramineus D Layer 37 C a n d e l a r i e l l a v i t e l l i n a 38 P e l t i g e r a canina var. rufescens 39 Physcia s t e l l a r i s 042(1.1) 062 (2. + ) 062(+.+) 062(1.+) 044(+.+) 042(3.3) 062(2.1) 062(1.1) 137 an A,B,C, horizon sequence was present. The A horizon i s seven to eight inches thick and contains an accumulation of organic matter. It overlies a lighter coloured, less melanized B horizon ranging i n thickness from eight to nine inches. The C horizon i s very light coloured and effervesces moderately with hydrochloric acid indicating a carbonate accumulation. In plots 044 and 062 a slig h t effervescence occurred indicating that some carbonate accumulation i s taking place. Texturally, the surface horizons are cl a s s i f i e d as sandy loams to s i l t loams and no coarse fragments were present i n any of the samples taken. With the exception of plot 062, which i s medium textured throughout, the so i l s increase in coarseness with depth and the sampled C horizons are composed largely of sand. Coarse fragments ranging i n size from gravels to stones were present i n a l l samples. These coarse particles are mostly basalts, thought to originate from local outcrops. The s o i l reaction i s sl i g h t l y alkaline near the surface and increases i n a l k a l i n i t y with depth. Measured pH values for the C horizon range from 8.2 to 8.5. This alkaline reaction i s due partly to weathering of the basic basaltic parent rock and partly to the secondary accumulation of basic cations in the C horizon as a result of leaching. Exchangeable calcium and magnesium are present in high amounts and increase s l i g h t l y i n concentration with depth indicating that some movement down the pr o f i l e due to leaching and drainage i s occurring. Exchangeable sodium i s present i n low amounts so should not interfere with the exchange complex. Exchangeable potassium and total phosphorus occur i n the surface horizons i n high concentrations and decrease i n amount down the p r o f i l e . Nitrogen i s present only in moderate amounts i n the A horizon and decreases to just trace amounts in the C horizon. However, the carbon:nitrogen ratios are generally low, suggesting that nitrogen i s present in sufficient amounts to satisfy the microflora Table 53 Soil Texture Opuntio (fragilis) - Stipetum comatae Number of Plots Plot No. 1 062 2 044 3 059 A Horizon Textural class SL Clay (%) 4 S i l t (%) 39 Sand (%) 57 Coarse fragments None B Horizon Textural class SL Clay (%) 2 S i l t (%) 43 Sand (%) 55 Coarse fragments None C Horizon Textural class SiL Clay (%) 4 S i l t (%) 50 Sand (%) 46 Coarse fragments None SiL 4 51 44 None SL 9 37 54 LS 8 19 73 g.c. SL 5 41 54 None SL 9 32 59 LS 6 11 83 g.c.s, 4 032 5 042 SL 3 48 48 None SL 8 46 45 g.c. LS 4 9 87 g.c.s. SiL 4 51 45 None SiL 6 53 41 g-SL 10 38 51 139 Table 54 Soil Chemical Analysis Opuntio (fragilis) - Stipetum comatae Number of Plots 1 2 3 4 5 Plot No. 062 044 059 032 042 A Horizon C% 7.2 6.4 7.3 3.8 14.6 N% .32 .41 .41 .14 .69 C/N 22.5 15.6 17.8 27.1 21.2 P ppm 11.0 9.0 13.0 6.0 21.0 Na .11 .12 .10 .28 .13 K .36 6.59 .77 1.09 5.38 Ca 8.6 11.5 7.5 5.0 9.0 Mg 2.3 4.3 2.9 5.8 5.6 CEC 31.7 34.6 34.8 19.3 41.8 pH 7.8 7.8 7.4 7.7 7.4 B Horizon C% 0 3.3 2.1 2.4 3.5 N% .13 .31 .13 .18 .14 C/N 0 10.6 16.2 13.3 25.0 P ppm 6.0 8.0 14.0 6.0 10.0 Na .14 .50 .12 .11 6.0 K .31 .30 .16 2.17 .24 Ca 11.7 20.5 13.8 8.0 8.0 Mg 3.5 7.9 4.8 10.8 7.7 CEC 8.4 26.7 23.5 13.7 27.3 pH 7.7 8.2 8.1 8.3 8.0 C Horizon C% 0 0 0 0 0 N% .05 .07 .09 .03 .06 C/N 0 0 0 0 0 P ppm 3.0 6.0 6.0 7.0 7.0 Na .83 .74 .91 .17 1.28 K .44 .26 .10 2.17 .25 Ca 12.5 22.5 13.3 8.5 21.5 Mg 5.6 8.1 5.9 7.1 9.5 CEC 7.1 5.6 4.1 3.8 13.1 pH 8.2 8.4 8.5 8.4 8.5 140 requirements as well as those of the higher plants. Percentage carbon ranges from 3.8% to 14.6% in the surface horizon indicating that organic saatter i s being incorporated into the s o i l . The amount of carbon decreases i n the B horizon to a range of 2.1% to 3.3%. No carbon was measureable in the C horizon. Even i n the profiles which do not have disti n c t horizons some organic matter accumulation occurs at the surface. The cation exchange capacities are high i n the sampled surface horizons ranging from 19.3 meg/100 g to 41.8 meg/100 g. Cation exchange capacity decreases rapidly with depth due to a decrease i n organic matter content and an increase i n sand content of the s o i l . Cation exchange capacities of the sampled C horizons ranged from 3.8 meg/100 g to 13.1 meg/100 g. The habitat of this association i s considered to be eutrophic. The s o i l s of the Opuntio - Stipetum comatae are cl a s s i f i e d either as Regosols (plots 044 and 062) or as Orthic Brown Chernozems although these do not appear to be well developed, and may actually be Rego Brown Chernozems. The lack of s o i l development here, i s possibly due partly to the extreme dryness of the habitat where evaporation appears to be a controlling factor and partly to constant deposition of fine s o i l from the slopes above as a result of erosion by wind and water. Structurally the Opuntio - Stipetum comatae has a well developed C • layer with a percentage cover ranging from 81% to 88% and a poorly developed D layer with a percentage cover ranging from 5% to 15%. In two plots sampled, isolated individuals of Artemisia tridentata occurred with low significance and thus constituted a fragmentary B horizon. The association i s dominated by Stipa comata with an average species significance of 7.8. Sporobolus cryptandrus i s a constant associate of high species significance, averaging 4,2. These species are both characteristic for the association and appear to be dependent on xeric habitats with regosolic 141 s o i l s . Artemisia fr i g i d a and Opuntia f r a g i l i s which are indicative of dry habitats occur with species significances of 3.6. Other constant species include: Koeleria g r a c i l i s , Lomatium macrocarpum, Tragopogon dubius and Arabis h o l b o e l l i i . Bryophytes are noteably lacking from the D layer and only Tortula  rur a l i s occurred with any degree of dominance. Lichens are more common under these xeric conditions and form most of the structure of this layer. Cladonia  pocillum, Lecidia decipiens, and Thrombium epigaeum are the constant species. Diploschistes canadensis i s the only other lichen species of importance and occurs with an average significance of 1.8. The Opuntio - Stipetum comatae has a history of moderate to severe grazing. Because of i t s topographic position and corresponding early release from snow this association forms an essential part of the early spring cattle range. Grazing at this time i s concentrated on the vegetation produced i n the preceding season. By the time active new growth begins, grazing pressure has usually been reduced and thus the association i s able to regain i t s vigor substantially. However, continued cropping may result in a serious reduction of organic matter accumulation i n the s o i l and therefore essential elements like nitrogen and phosphorus could become limiting. The Opuntio - Stipetum comatae also appears to be promoted to some extent by grazing as the dominant, Stipa comata, can withstand grazing pressures better than other dominants of this area, for example, Agropyron  spicatum. Tisdale (1947) and Brayshaw (1955) reported that this association i s largely promoted by grazing. L42 Fig. 16. The Opuntio - Stipetum comatae shown here as developed on a gently sloping terrace. Stipa comata dominates the association and gives i t a characteristic appearance. Fig. 17. The Agropyro - Juniperetum scopulorum on a steep south facing slope. It i s dominated by Juniperus scopulorum, Artemisia tridentata and Agropyron spicatum and i s characteristic of unstabilized slopes. 143 4. Agropyro (spicati) - Juniperetum scopulorum (ref. Tables; 55,56, 57, 58, 83, and Fig. 17) Characteristic Combination of Species Order Characteristic Species Agropyron spicatum Artemisia frigida Erigeron f l a g e l l a r i s Arabis h o l b o e l l i i Koeleria g r a c i l i s Tortula ruralis Alliance Characteristic Species Comandra umbellata Lithospermum ruderale Opuntia f r a g i l i s Diploschistes canadensis Lecidea decipiens Association Characteristic Species Chrysothamnus nauseosus Juniperus scopulorum Important Companion Species Artemisia tridentata Artemisia dracunculus Stipa comata Sporobolus cryptandrus The Agropyro - Juniperetum scopulorum occurs on steep exposed slopes or on the steep sides of water cut ravines. Measured slope gradients range from 28° to 44°. The exposures are usually southerly, although two plots had northwest exposures. The surface topography ranges from straight to convex. The s o i l surface i s partly covered by a thin layer of l i t t e r ranging in extent from 42% to 88% of the surface area. A large amount of mineral s o i l was exposed i n a l l plots sampled and i n four plots rocks were present on the s o i l surface. The soi l s of this association are considered to be well drained and the hygrotope i s rated as xeric. There i s evidence of surface erosion varying in intensity from moderate to extreme which i s caused by surface runoff water. Erosion due to 144 Table 55 Agropyro ( s p i c a t i ) - Juniperetum scopulorum P l o t Data Number of P l o t s 1 2 3 4 5 6 7 Pl o t No. 092 093 083 084 085 086 017 P l o t Size (m2) 100 100 100 100 100 100 100 Date analyzed 31/7 31/7 20/7 20/7 20/7 24/7 8/7 1968 1968 1968 1968 1968 1968 1967 El e v a t i o n (ft) 2000 2050 2100 2160 2200 2200 2560 • L o c a l i t y FP FP FP FP FP FP WL 51°48' 51°48' 51°48' 51°48' 51°48' 51°50' 52°26' 122°33' 122°33' 122°32' 122°31' 122°32 ' 122°34' 122°20 Physiography Landform R e l i e f shape Exposure Slope gradient (°) Layer coverage (%) A3 l a y e r B2 l a y e r C la y e r D l a y e r P l o t coverage (%) Humus and l i t t e r Mineral s o i l Rock S o i l Hygrotope Trophotope Erosion Drainage Sample depth (in) 1 2 3 Parent material exposed slope convex S 36 68 12 10 72 28 convex S 33 20 62 10 8 71 26 3 .side of ravine s t r a i g h t . SW 28 36 12 14 42 48 8 NW 44 4 52 72 40 88 11 very x e r i c .permesotrophic NW 34 8 43 52 21 64 32 subxeric (eutrophic) S 33 22 61 24 6 55 45 4 exposed slope SW 33 11 52 5 58 32 10 strong extreme extreme moderate moderate strong moderate water water water water water water water 0-6 12-18 24-30 aeoli a n deposit 0-6 12-18 g l a c i a l d r i f t 0-6 12-18 24-30 g l a c i a l d r i f t . well 0-6 12-18 24-30 0-6 12-18 24-30 0-6 12-18 0-6 12-18 24-30 ae o l i a n depo-s i t over gla-. . c i a l d r i f t . . . g l a c i a l g l a c i a l d r i f t d r i f t 145 Table 56 Agropyro (spicati) - Juniperetum scopulorum Sporadic species C Layer 74 A c h i l l e a millefolium 25 Arctostaphylos uva-ursi 26 Astragalus miser 27 Koeleria g r a c i l i s 28 Linum l e w i s i i 29 Lithospermum ruderale Number of Plots 1 2 3 4 5 6 7 Plot No. 092 093 083 084 085 086 017 Plot Size (m2) 100 100 100 100 100 100 100 Elevation (ft) 2000 2050 2100 2160 2200 2200 2560 sub Avg Species A L a y e r layer Constancy Significance 1 Pseudotsuga menziesii 3 5.+ - 3.+ 4.+ 5.+ - IV 3.0 B Layer 2 Juniperus scopulorum 2 7.4 8.4 6.3 7.3 6.4 7.6 4.+ V 6.4 3 Artemisia tridentata 2 4.3 4.3 4.3 4.3 5.3 4.2 - V 4.2 4 Chrysothamnus nauseosus 2 2.2 3.2 3.3 2.2 2.1 3.2 - V 2.5 C Layer 5 Agropyron spicatum 4.2 4.2 4.2 8.3 7.2 5.2 5.2 v 5.3 6 Artemisia f r i g i d a 4.2 3.1 3.1 3.1 3.1 4.1 5.2 V 3.5 Artemisia tridentata 2.1 1.+ 2.1 2.1 2.1 1.+ - 1.4 Chrysothamnus nauseosus 2.+ 1.+ 1.1 - 2.+ 1.+ 1.+ 1.1 Juniperus scopulorum 2.1 1.1 1.1 - 2.1 2.1 - 1.2 7 Comandra umbellata 1.1 - 1.+ +. + - 1.+ 3.+ IV 0.9 8 Artemisia dracunculus 2.+ - 2.1 1.+ 2.+ - - III 1.0 9 Solidago multiradiata - - - 3.1 2.+ 2.+ - III 1.0 10 Artemisia campestris - - - - - 3.+ 5.1 II 1.2 11 Erigeron f l a g e l l a r i s - - - 4.2 - - 2.2 II 0.8 12 Stipa comata 3.2 - +. + - - - - II 0.7 13 Opuntia f r a g i l i s 2.2 - - - - - 2.2 II 0.6 14 Sporobolus cryptandrus 1.+ - - - - 1.+ - II 0.2 15 Arabis h o l b o e l l i i + .+ - - - - - + .+ II 0.1 D Layer (Bryophytes) 16 Tortula r u r a l i s 4.2 3.2 4.3 6.3 4.3 4.2 3.1 v 4.3 17 Ceratodon purpureus - 3.2 2.2 3.2 3.2 - - II 1.6 18 A b i e t i n e l l a abietina'' - - - 4.3 4.2 - - II 1.3 (Lichens) 19 Dermatocarpon hepaticum 3.2 2.2 2.1 1.1 2.2 1.1 - V 1.6 20 Lecidea decipiens 2.2 2.2 3.1 1.1 2.2 1.1 - V 1.6 21 Fulgensia fulgescens 1.1 1.1 1.1 - - - - III 0.4 22 Diploschistes scruposus - 2.1 2.1 - - 1.1 - II 0.7 23 Physcia s t e l l a r i s 2.1 ~ 2.1 — II 0.6 TOTAL SPECIES ( i n c l . sporadics) 19 15 21 18 16 14 17 017(2.2) 083(2.1) 083(1.+) 0 1 7 ( 1 . + ) 0 1 7 ( 2 . 0 1 7 ( 2 . 2 ) D Layer 30 C a n d e l l a r i e l l a v i t e l l i n a 017(1.+) 31 Collema tenax 083(2.+) Diploschistes canadensis 017(1.+) Lecidea auriculata 017(1.+) 32 33 34 Peltigera canina var. 35 Peltigera malacea rufescens084 (3.2) 084 (2.2) 146 wind also occurs in these habitats as evidenced by the presence of unstabilized sand dunes and the frequent occurence of dust storms. The s o i l i s formed from parent materials of aeolian deposits, aeolian deposits overlying g l a c i a l d r i f t or on g l a c i a l d r i f t . The g l a c i a l d r i f t here appears to be a coarse outwash material. No distinct horizons were present in the sampled s o i l s . The s o i l i s relatively coarse textured and sampled soils ranged from loamy sands to s i l t loams. There i s no significant textural change with depth. With the exception of plot 092 which i s formed on aeolian deposits, coarse fragments ranging i n size from gravels to stones were present i n a l l samples. The s o i l reaction i s alkaline and does not change significantly with increasing depth. Measured pH values range from 7.3 to 8.4. Exchangeable cations are present in moderate amounts and there i s no indication of con-centration changes down the p r o f i l e . Calcium i s the most abundant cation followed by magnesium. The high concentration of these cations i s probably because the parent rock of the s o i l i s mostly basalt and this may also account for the alkaline reaction of the s o i l . Exchangeable sodium and potassium were present in low amounts in a l l samples. There i s very low accumulation of organic matter in this association and carbon was measureable in the surface samples of only three plots. Correspondingly, available phosphorus and total nitrogen are present i n low quantities. Cation exchange capacity i s only moderately high partly because of the lack of organic matter in the s o i l and partly because of the coarseness of the s o i l . Trophically this association i s considered to be permesotrophic up to eutrophic. The soi l s are c l a s s i f i e d as Orthic Regosols as they are practically unaltered from the original parent material. The lack of s o i l development in this association i s probably due to the general unstabelness of the slopes. These are being actively eroded and thus vegetation colonization and accompanying Table 57 Soil Texture Agropyro (spicati) - Juniperetum scopulorum Number of Plots Plots No. 1 092 2 093 3 083 4 084 5 085 6 086 7 017 Sample 1 Textural class LS SL Clay (%) ' 2 8 S i l t (%) 22 " 34 Sand (%) 76 58 Coarse fragments None g.c. Sample 2 Textural class LS Clay (%) 1 S i l t (%) 25 Sand (%) 74 Coarse fragments None g.c.s. Sample 3 Textural class SL Clay (%) 4 S i l t (%) 34 Sand (%) 62 Coarse fragments None g.c.s. SL 3 41 55 g.c. SiL 8 52 40 g.c. SiL 1 51 48 g.c.s* SL 5 44 51 None SL 5 38 57 g. SL 2 42 56 g. SL 1 41 58 None SL 2 41 56 g. SL 2 35 63 g.c. SL 16 24 60 g.c. L 21 31 48 g.c. g.c.s. SL 18 24 58 J g. SL 15 17 68 g.c. SL 15 17 68 g. c. 148 Table 58 Soil Chemical Analysis Agropyro (spicati) - Juniperetum scopulorum Number of Plots 1 2 3 4 5 6 7 Plot No. 092 093 083 084 085 086 017 Sample 1 C% 0 0 0 2.0 4.1 3.4 0 N% .08 .10 .10 .15 .09 .31 .05 C/N 0 0 0 13.0 45.6 10.9 0 P ppm 0 11.0 5.0 4.0 13.0 3.0 2.0 Na .29 .25 1.18 .67 3.3 .45 1.06 K .34 .82 .17 .12 .16 .56 .29 Ca 14.6 18.2 12.8 19.4 18.5 14.0 6.2 Mg 1.8 4.1 5.8 4.7 7.5 8.3 3.3 CEC 0 34.7 13.6 8.4 23.7 8.1 18.3 PH 7.9 8.1 7.9 8.0 7.9 7.7 7.3 Sample 2 C% 0 - 0 N% .12 - .08 C/N 0 - 0 P ppm 5.0 - 7.0 Na .47 - 5.6 K .65 - .72 Ca 16.9 - 11.1 Mg 5.7 - 7.6 CEC 4.8 - 7.3 pH 8.1 - 8.2 0 3.3 0 0 .06 .18 .08 .05 0 27.5 0 0 7.0 6.0 3.0 5.0 2.3 3.5 .41 1.05 .16 .29 .68 .16 12.6 12.3 14.9 7.6 7.2 6.3 7.4 3.3 13.1 18.9 3.8 16.4 8.0 7.8 7.8 8.2 Sample 3 C% 0 - 0 N% .07 - .05 C/N 0 - 0 P ppm 5.0 - 6.0 Na .27 - 7.10 K .85 - .77 Ca 16.2 - 15.4 Mg 4.7 - 9.3 CEC 4.6 - 11.6 pH 7.9 - 8.1 0 1 . 9 - 0 .07 .12 - .05 0 15.8 - 0 5.0 6.0 - 6.0 3.2 .66 - .57 .29 .20 - .13 15.5 20.8 - 6.7 5.5 7.0 - 13.0 17.9 17.3 - 11.9 8.0 8.1 - 8.4 149 organic matter accumulation i s limited. Structurally, this association has four vegetation l a y e r s — a poorly developed tree layer (A), a well developed shrub layer (B), a well developed herb layer (C) and a moderately well developed bryophyte and lichen layer (D). Juniperus scopulorum dominates the association with an average species significance of 6.4. Artemisia tridentata and Chrysothamnus nauseosus are constant associates of the shrub layer with average species significances of 4.2 and 2.5 respectively. A l l three species are also present in the C layer with lower species significances. Juniperus scopulorum because of i t s low spreading growth form tends to stabilize the s o i l surface and conserve surface moisture which may favour the growth of arboreal species. Pseudotsuga menziesii i s the only tree species present and occurs with low abundance. It i s always associated with a mat of Juniperus scopulorum. Agropyron spicatum i s the dominant species of the C layer and occurs as isolated bunches. Vegetative spread of this species appears to be limited by surface runoff. The only other constant species i s Artemisia frigida which i s characteristic of exposed habitats. Other species characteristic of this association but occurring with lower constancy and species significance include: Comandra umbellata, Artemisia dracunculus, Erigeron f l a g e l l a r i s , Opuntia f r a g i l i s , Stipa comata, Sporobolus cryptandrus, and Arabis h o l b o e l l i i . Artemisia  campestris, a species characteristic of dry habitats with coarse textured soil s i s present here, but with low species significance and constancy. A l l species composing the C layer have very low soci a b i l i t y values indicating the open dispersed pattern of the individual plants. This appears to be caused largely by the severe surface erosion. The D layer i s dominated by bryophytes which occur mostly in patches at the bases of woody plants where moisture i s available. Tortula ruralis 150 i s the dominant bryophyte with an average species significance of 4.3. Ceratodon purpureus and Abietinella abietina are the only other bryophytes of importance and both occur with low constancy and significance. The only constant lichen species are Dermatocarpon hepaticum and Lecidea decipiens, both occurring with a species significance of 1.6. The Agropyro - Juniperetum scopulorum differs from other members of the Agropyrion spicati by the greater dominance of woody plants. It i s thought that the coarse s o i l favours the growth and development of these species. Also their deep rooting habit makes them more successful than shallow rooting herb species in this well drained habitat where erosion results in the constant removal of surface s o i l . The Agropyro - Juniperetum scopulorum appears to have a history of light burning as evidenced by the moderate f i r e scars on some of the trees. Grazing i s negligible here, probably because of the inaccessibility of this association. Pseudotsugetalia menziesii Most of the forested area of the Cariboo Zone i s composed of communities cl a s s i f i e d into the Pseudotsugetalia menziesii. The soil s of these communities are formed on coarse textured parent materials of glac i a l d r i f t . The habitats range trophically from submesotrophic to permesotrophic, and hyrotopically from subxeric to subhygric. The Pseudotsugetalia menziesii i s believed to reach i t s most northern extension i n the Cariboo Zone. F l o r i s t i c a l l y , because of i t s geographical, location, the order i s enriched by many Canadian boreal species in this zone. The Order i s characterized by: Pseudotsuga menziesii, Arctostaphylos  uva-ursi, Carex concinnoides, Hieracium umbellatum, Spiraea b e t u l i f o l i a , Dicranum polysetum, Cladonia chlorophaea, Cladonia g r a c i l i s , Cladonia mitis, Cladonia 151 rangiferina, and Peltigera aphthosa. Two alliances are recognized for the Pseudotsugaetalia menziesii— the Arctostaphylo (uva-ursi) - Junipero (communis) - Pseudotsugion *glaucae and the Calamagrostido (rubescentis) - Pseudotsugion *glaucae. Arctostaphylo (uva-ursi) - Junipero (communis) -Pseudotsugion *glaucae. The Arctostaphylo - Junipero - Pseudotsugion *glaucae has a restricted distribution and appears to be confined to coarse subxeric outwash s o i l s . It i s represented by a single association in the Cariboo Zone. The Arctostaphylos type described by Ilvessalo (1929) and the Arctostaphylos association described by Brayshaw (1965) would be included i n this alliance Calamagrostido (rubescentis) - Pseudotsugion *glaucae The Calmagrostido - Pseudotsugion *glaucae i s widely spread in the Cariboo Zone and i s present on submesic to subhygric habitats. It i s characterized by: Calamagrostis rubescens, Aster conspicuus, Hypnum revolutum, Polytrichum juniperinum and Rhytidiadelphus triguetrus. The Pseudotsuga -Calamagrostis association and the Pseudotsuga - Arctostaphylos - Calamagrostis association described by Brayshaw (1965); the Calamagrostis - Arctostaphylos and Calamagrostis types described by Ilvessalo (1929); the Arctostaphylos -Calamagrostis and Calamagrostis types described by Kujala (1945) and the Pseudotsuga - Calamagrostis association described by Daubenmire (1952) would be included in this alliance. This alliance i s represented by two associations in the Cariboo Zone. Arctostaphylo (uva-ursi) - Junipero (communis) - Pseudotsugion *glaucae Arctostaphylo (uva-ursi) - Junipero (communis) - Pseudotsugetum *glaucae (ref. Tables; 59, 60, 61, 62, 83, and Fig. 18) Characteristic Combination of Species 152 Order Characteristic Species Pseudotsuga menziesii Arctostaphylos uva-ursi Carex concinnoides Hieracium umbellatum Spiraea b e t u l i f o l i a Dicranum polysetum Cladonia chlorophaea Cladonia g r a c i l i s Cladonia mitis Cladonia rangiferina Peltigera aphthosa Alliance and Association Characteristic Species Juniperus communis Prunus virginiana Apocynum androsaemifolium Artemisia campestris Gaillardia aristata Oryzopsis pungens Selaginella densa Cladonia nemoxyna Important Companion Species Pinus contorta Amelanchier a l n i f o l i a Shepherida canadensis Rosa acicularis Allium cernuum Agropyron spicatum Fragaria virginiana Solidago multiradiata Stipa richardsonii Tortula ruralis The Arctostaphylo - Junipero - Pseudotsugetum *glaucae develops on slopes with a surface topography which i s convex or straight. The slopes are moderately steep with measured gradients ranging from 17° to 24° and have southerly exposures. Snow accumulation i s low and duration short on these sites which are usually snow free by March 30. The s o i l surface i s covered by an extensive but very thin layer of l i t t e r composed mostly of Pseudotsuga menziesii leaves. In a l l sampled plots mineral s o i l was exposed, and in four plots rocks were present on the surface. The surface of sampled plots showed evidence of only slight water erosion 153 Arctostaphylo (uva-ursi) - Junipero (communis) -Pseudotsugetum *glaucae P l o t Data Number of Plots 1 2 3 4 5 6 7 Plot No. 016 057 058 018 009 010 056 Pl o t Size (m2) 400 400 400 400 400 400 400 Date analyzed 7/7 28/8 29/8 8/7 27/6 28/6 27/8 1967 1967 1967 1967 1967 1967 1967 Elevation (ft) 2500 2600 2650 2700 2800 2800 2850 L o c a l i t y WL WL WL WL WL WL WL 52°17' 52°17' 52°17' 52°27" 52°12' 52°12' 52°12' 122°14 ' 122°14' 122°13 ' 122°21' 122°13' 122°14' 122°13 Physiography Landform slope (outwash terrace) slope slope (outwash terrace' ( t a l l u s ) , R e l i e f shape convex s t r a i g h t convex s t r a i g h t s t r a i g h t s t r a i g h t convex Exposure SW SE SE SE SW SW SW Slope gradient (°) 21 19 17 24 22 23 21 Layer coverage (%) Aj layer - - - - 4 - 14 A 2 layer 9 24 9 17 12 10 16 A 3 layer 3 12 15 2 4 2 3 layer 5 5 6 15 13 5 1 B 2 layer 41 27 26 31 34 32 16 C layer 54 76 79 23 48 42 62 D layer 28 44 55 5 18 12 41 Plot coverage (%) Humus and l i t t e r 86 97 92 88 56 65 89 Mineral s o i l 12 3 7 4 43 33 9 Decaying wood 2 - 1 1 1 - -Rock - - - 7 2 2 3 S o i l Hygrotope Trophotope Erosion Drainage Horizon depth (in) L-H 1/2-0 1/2-0 1/2-0 1/2-0 1/2-0 n i l 1/2-0 Bl 0-10 0-4 0-4 0-6 0-3 0-4 0-5 B 2 10-25 4-14 4-23 0-14 3-19 4-22 5-24 C 25-56+ 14-41+ 23-50+ 14-30+ 19-48+ 22-58+ 24-42+ Parent material sandy outwash colluvium ....sandy outwash over outwash 60 Arctostaphylo (uva-ursi) - Junipero (communis) - Pseudotsugetum *glaucae 154 Number of P l o t s P l o t No. P l o t S i z e <m2) E l e v a t i o n ( f t ) 1 2 3 4 5 6 7 016 057 058 016 009 010 056 400 400 400 400 400 400 400 2500 2600 2650 2700 2800 2800 2850 A Layer-1 Pseudotsuga m e n z i e s i i 2 Pinus contorta B Layer 4.* 3.* 5.* 4.+ 4 3.+ 4.+ 4 .• 4.1 4.1 5.* 3.* 3. * 4. » 3.* 1.* l.« 4.+ 2.* 5.+ 5.* 3.+ Constancy Avg Species S i q n i f i c a n c e 1.1 4.4 3.1 1.3 1.1 3 Juniperus communis 2 7 5 5 3 6 4 4 3 6 5 6 4 5 4 V 5 6 Pseudotsuga m e n z i e s i i 1 3 + 4 + 3 + 1 + 5 2 3 1 3 + 3 1 2 2 + 3 + 3 + + + 1 + 1 + 2 1 1 8 4 Shepherdia canadensis 2 1 + 3 1 1 1 3 3 2 2 2 2 3 1 V 2 1 5 Rosa a c i c u l a r i s 2 + + 2 + 2 2 2 1 1 1 2 + 2 2 V 1 6 6 Amelanchier a l n i f o l i a 2 + -f 3 2 1 1 1 + + * 2 1 V 1 1 7 Spiraea b e t u l i f o l i a 2 2 2 2 2 2 1 1 1 V 1 0 8 Prunus v i r g i n i a n a 2 3 2 2 1 2 1 I I I 0 9 9 Juniperus scopulorum 2 5 2 + + II 0 8 Pinus contorta 1 2 2 + 3 1 + + 0 0 7 1 10 Arctostaphylos uva-ursi 7.5 8 6 8 5 4 3 7 5 6 4 7 5 V 6 7 11 Carex concinnoides 4.2 4 3 6 3 4 2 3 2 3 3 4 2 V 3 7 12 Oryzopsis pungens 3.1 4 2 4 2 2 1 3 1 4 2 V 2 9 13 Apocynum androsaemifolium 3.1 4 + 4 + + + 2 + 1 + 5 1 V 2 8 14 Agropyron spicatum 2.1 2 1 2 1 3 2 3 1 2 1 3 2 V 2 4 15 A r t e m i s i a campestris 2.+ 2 + 2 1 1 + 3 + 3 + 1 + V 2 0 16 Solidago m u l t i r a d i a t a 1.1 2 1 2 1 2 + 2 + 2 2 3 1 V 2 0 17 A s t e r c i l i o l a t u s 2.+ 2 + 1 + 3 + 1 + 2 1 + + V 1 6 Spiraea b e t u l i f o l i a 1.+ 2 + 2 + 3 + + + 2 2 .+ + 1 6 18 A c h i l l e a m i l l e f o l i u m 1.+ 1 + 1 + 2 2 1 + 1 + 2 + V 1 4 19 F r a g a r i a v i r g i n i a n a 1.+ 2 + 2 1 1 + 1 + 2 1 1 + V 1 4 20 A l l i u m cernuum 2.+ 2 1 + + + 2 1 + + + V 1 3 Rosa a c i c u l a r i s 2.+ 1 1 1 + 1 + 1 + 1 + 2 + V 1 3 21 Anemone m u l t i f i d a 2.1 1 + 1 + + + + + 2 1 + + V 1 1 Pseudotsuga m e n z i e s i i + .+ 1 + 1 + 1 + 1 + 0 6 22 Lathyrus ochroleucus 1.+ 2 1 3 1 I I I 0 9 23 Hieracium umbellatum 1.+ i + 1 + 2 + I I I 0 7 24 S t i p a r i c h a r d s o n i i + .+ 2 + 2 2 I I I 0 6 25 G a i l l a r d i a a r i s t a t a + .+ 1 1 + I I I 0 4 26 A r a b i s h o l b o e l l i i - 1 + + + + + I I I 0 3 Juniperus communis - 1 + 1 1 0 3 27 Galium boreale 1.+ 1 + II 0 3 28 v i c i a americana 1 + II 0 2 29 Festuca saximontana - + + + + II 0 1 30 V i o l a adunca +.+ + + II 0 1 D Laver 31 S e l a g i n e l l a densa 5.3 6 3 6 4 4 4 4 4 6 5 V 4 4 (Bryophytes) 32 T o r t u l a r u r a l i s 4.2 4 3 4 3 3 2 3 3 3 2 3 2 V 3 4 33 Ceratodon purpureus 4.2 3 2 3 2 2 1 2 1 3 2 2 1 V 2 7 34 Dicranum polysetum 2.1 3 2 2 2 + + 2 1 IV 1 2 35 Pleurozium s c h r e b e r i 1.1 2 2 2 1 2 1 III 0 9 (Lichens) 36 Cladonia p o c i l l u m 3.3 4 2 4 1 4 2 3 2 3 2 4 2 V 3 6 37 Cladonia g r a c i l i s 3.1 3 1 3 1 3 1 2 1 3 2 3 1 V 3 3 38 P e l t i g e r a malacea 2.1 3 1 3 1 2 1 2 2 2 1 3 2 V 2 4 39 D i p l o s c h i s t e s canadensis 1.1 1 + 1 + 1 1 1 + 1 + V 0 9 40 P e l t i g e r a canina var. rufescens 2.2 2 1 1 1 3 3 3 1 IV 1 6 41 Cladonia nemoxyna 2.2 2 1 2 3 1 1 2 1 IV 1 3 42 Cladonia pyxidata 1.+ 2 1 2 1 2 + 2 1 IV 1 3 43 Cladonia m i t i s 2.1 2 1 1 1 2 1 I I I 2 9 44 Cladonia chlorophaea 3.2 3 2 3 1 2 1 III 1 6 45 Cladonia r a n g i f e r i n a - 2 1 1 1 2 1 I I I 0 9 46 Stereocaulon tomentosum 2.1 3 2 II 0 7 47 C e t r a r i a ericetorum 2.1 2 1 II 0 6 48 P e l t i g e r a canina var. s p u r i a - 2 1 1 + II 0 4 49 Cladonia f i m b r i a t a 1.+ 1 + II 0 3 50 P e l t i g e r a aphthosa 1.+ 1 + II 0 3 51 P e l t i g e r a canina var. canina - 1 + 1 1 II 0 3 52 P e l t i g e r a lepidophora 1.1 1 1 II 0 3 TOTAL SPECIES ( i n c l . sporadics) Sporadic species B Layer 53 Populus tremuloides 54 Symphoricarpos o c c i d e n t a l i s C Layer 55 Acer glabrum 56 Antennaria neglecta 57 Antennaria p a r v i f o l i a 58 Ceanothus sanguineus 59 K o e l e r i a g r a c i l i s 60 Oryzopsis a s p e r i f o l i a Epiphytes 71 A l e c t o r i a g l a b ra 72 C e t r a r i a canadensis 73 Hypogymnia physodes 74 L e t h a r i a v u l p i n a 75 Parmelia s u l c a t a 76 C e t r a r i a h a l e i 77 Hypogymnia v i t t a t a 78 Usnea glabrescens 79 C e t r a r i a s c u tata 80 Lecanora subrugosa 81 Parmeliopsis ambigua 058<+.+> 018(3.1) 018(+.+> 009{+. + ) 018(2.1) 018(+.+) 018(3.2) 057(2.1) (V) (V) (V) (V) (V) (IV) (IV) (IV) (III) (III) (III) 61 Cladonia cenotea 62 Cladonia c o c c i f e r a 63 Cladonia cornuta 64 Cladonia c r i s p a t a 65 Dicranum fuscescens 66 Eurhynchium pulchellum 67 Hedwigia c i l i a t a 68 Parmelia chlorochroa 69 P e l t i g e r a h o r i z o n t a l i s 70 Rhacomi trium heteros t i chum. 82 Parmeliopsis hyperopta 83 Usnea h i r t a 84 Usnea s o r e d i i f e r a 85 Candelaria concolor 86 C e t r a r i a p i n a s t r i 87 Lecanora cadubr i ae 88 A l e c t o r i a americana 89 C e t r a r i a p l a t y p h y l l a 90 C e t r a r i a glauca 91 Usnea a l p i n a 9 2 Usnea g l a b r a t a 016(1.1 057(2.1 058(2.1 016 (2.2 057 (1.+ 057(1.1 018(1.+ 018I+.+ 018(1.+ 018(3.1 (III (III (III (II (II (II (I (I (I (I (I 155 indicating that surface runoff i s minimal. The s o i l has three mineral horizons formed under a thin L-H horizon. The surface horizon i s a dark coloured horizon ranging i n thickness from three inches to 10 inches and i t overlies a lighter coloured B2 horizon varying i n thickness from eight inches to 19 inches. Below the B 2 horizon i s a C horizon of undetermined depth. In two plots the C horizon showed a slight effervescence with hydrochloric acid, indicating the presence of carbonates. A study of the root distribution shows that roots are mostly concentrated in the surface horizons and only a few roots reach as deep as the C horizon. With the exception of plot 018, a l l horizons are composed mostly of sand and the sampled soil s are c l a s s i f i e d texturally, as sands. In plot 018 the horizon i s c l a s s i f i e d as a loam with only 39% sand. However, sand increases in amount with depth and 90% of the C horizon i s composed of sand. Coarse fragments ranging in size form gravels to stones were present in a l l sampled horizons. These fragments are mostly cherts, quartzites and shales which belong to the Cache Creek Group (geological formation after Tipper 1959). The Parent material of the s o i l s i s sandy g l a c i a l outwash with the exception of plot 018. In plot 018, which i s located at the base of a rock out-crop, the parent material i s considered to be colluvium overlying g l a c i a l d r i f t . The s o i l s of this association are very rapidly drained because of their coarse texture. The hygrotope of the Arctostaphylo - Junipero - Pseudotsugetum *glaucae i s rated as subxeric. Based on geomorpholocical evidence the slopes containing this assoc-iation are considered to be parts of outwash terraces. Plot 018 appears to be an exception and is thought to occur on a talus slope. The s o i l reaction i s circumneutral at the surface with pH values in the B horizon ranging from 6.7 to 7.1. It becomes alkaline with depth and pH Arctostaphylo (uva-ursi) Table 61 Soil Texture - Junipero (communis) - Pseudotsugetum *glaucae Number of Plots Plot No. 1 016 2 057 3 058 4 018 5 009 6 010 7 056 Horizon Textural class S S Clay (%) 5 2 S i l t (%) 3 2 Sand (%) 92 96 Coarse fragments g.c. g.c. B2 Horizon Textural class S S Clay (%) 0 5 S i l t (%) 0 7 Sand (%) 100 88 Coarse fragments g.c. g.c.s. C Horizon Textural class S S Clay (%) 1 0 S i l t (%) 1 1 Sand (%) 98 99 . Coarse fragments g.c.s. g.c.s. S 5 7 88 g.c. S 2 2 96 g.c.s. S 0 0 100 g.c.s. L 25 36 39 g.c.s. LS 4 25 71 g.c.s. S 1 9 90 g.c.s. S 2 0 98 g. s 1 0 99 g.c. S 5 5 90 g.c. S 4 5 91 g. S 2 4 94 g. s 2 0 98 g.c. S 5 5 90 g.c. S 1 1 98 g.c. LS 5 10 85 g.c.s. 157 Number of Plots 1 Plot No. 016 L-H Horizon Table 62 Soil Chemical Analysis Arctostaphylo (uva-ursi) - Junipero (communis) Pseudotsugetum *glaucae 2 '3 4 5 057 058 018 C% N% C/N P ppm Na K Ca Mg CEC pH Horizon C% N% C/N P ppm Na K Ca Mg CEC PH B2 Horizon 22.5 1.06 21.2 16.0 .88 .43 17.1 2.9 45.0 6.9 1.5 .08 18.8 5.0 1.06 .11 4.2 1.3 7.1 6.9 009 31.8 1.62 19. 15. .6 .0 .17 .51 17.5 3.7 42.6 6.3 2.0 .09 22.2 13.0 .10 .77 4.8 .9 12.0 6.9 24.0 1.17 20.5 18.0 .18 .71 14.0 2.8 51.7 5.7 7.3 .41 17.8 13.0 .10 .19 4.5 1.1 34.8 6.9 18.6 .93 20.0 12.0 .68 1.44 16.1 5.7 48.5 7.1 4.9 .31 15.8 12.0 1.03 .68 No L-H 9.8 12.3 28.8 7.5 2.2 .16 13.8 5.0 .07 .26 3.45 .78 11.7 6.8 6 010 16.3 .81 20.1 24.0 .17 .47 10.2 1.73 19.3 7.1 3.4 .22 15.5 9.0 .09 .28 3.2 .8 13.5 6.7 7 056 36.8 1.49 24.7 18.0 .19 .46 13.0 2.2 41.5 6.1 3.4 .18 18.9 5.0 .09 .45 10.0 1.2 26.1 7.1 c% 0 0 2.1 2.9 0 0 0 N% .03 .13 .13 .30 .02 .06 .10 C/N 0 0 16.2 9.7 0 0 0 P ppm 6.0 6.0 14.0 16.0 6.0 13.0 4.0 Na .45 .10 .09 .57 .09 .09 .09 K .03 .17 .04 .62 .15 .13 .09 Ca 6.5 4.5 4.0 14.8 3.25 2.7 4.5 Mg 8.0 1.0 1.7 15.7 .98 .82 1.9 CEC 3.4 6.1 23.5 19.2 8.3 16.4 4.7 pH 8.2 6.9 7.0 8.0 6.9 6.9 6.5 jrizon C% 0 0 0 3.3 0 0 0 N% .02 .11 .09 .21 .03 .05 .08 C/N 0 0 0 15.7 0 0 0 P ppm 3.0 5.0 6.0 10.0 4.0 8.0 5.0 Na 1.4 .08 .09 1.35 .09 .09 .09 K .05 .10 .03 .56 .06 .07 .05 Ca 4.7 7.0 5.3 23.0 4.15 3.0 3.5 Mg 7.2 .8 .8 22.3 .75 1.4 1.9 CEC 6.0 0 4.1 18.8 10.1 4.4 0 pH 8.0 7.9 8.0 8.3 7.8 7.3 7.0 158 values of the C horizon range from 7.0 to 8.3. This suggests that the parent material i s alkaline. The lower pH values at the surface are probably due to incorporation into the s o i l of humic acids derived from the L-H horizon which has pH values ranging from 5.7 to 7.1. Available phosphorus and total nitrogen are present in relatively high amounts in the L-H horizon and the carbon:nitrogen ratios are low indicating that the organic matter contains sufficient nitrogen for decomposition. There i s an accumulation of organic matter i n the horizon as judged by the presence of carbon which ranges from 1.5% to 7.3%. In the B^ horizon nitrogen i s present i n low amounts but the carbon:nitrogen ratios are also low indicating that n i t r i f i c a t i o n i s taking place and that nitrogen i s available to higher plants. The amount of carbon decreases with depth and i s present i n the B£ horizon of only two plots and in the C horizon of only one plot. Similarly, total phosphorus and total nitrogen decrease i n amounts from the surface down the p r o f i l e with nitrogen being present in only trace amounts in the lower horizons. Exchangeable cations are present i n the mineral s o i l i n low amounts with calcium dominating the exchange complex. The calcium concentration of the l i t t e r i s substantially higher than that of the mineral s o i l because of the high amount of calcium present in the l i t t e r of Pseudotsuga menziesii (Daubenmire 1953). Exchangeable sodium and magnesium are present i n very low amounts as i s potassium which decreases constantly with depth. The cation exchange capacity i s very high in the L-H horizon because of the high amount of organic matter present. It decreases sharply through the mineral horizons. The lower cation exchange capacity i s due partly to the lower concentration of organic matter and partly to the coarse texture of the s o i l . These soils do not appear to be rich and thus are considered to be submesotrophic to oligotrophic. The soi l s are cl a s s i f i e d as Orthic Brown Wooded soil s because they have an L-H horizon, a brownish B horizon and a weakly acidic to slig h t l y 159 alkaline s o i l reaction. Structurally, the vegetation of this association i s composed of four layers. The tree layer i s represented by three sublayers of which the A2 i s best developed with a percentage cover ranging from 9% to 24%. The shrub layer consists of two sublayers—a poorly developed B^ layer with a coverage ranging from 1% to 15% and a well developed B2 layer with a coverage ranging from 16% to 41%. The herb layer (C) has a percentage cover ranging from 23% to 79% and the D layer i s variably developed with a percentage cover ranging from 5% to 55%. Pseudotsuga menziesii dominates the association and i s present in a l l three sublayers of the tree layer. It has a low density and forms an open canopy. The only other tree species present i s Pinus contorta which occurs in the A2 and A^ layers but only with a constancy of class III. The B^ layer consists entirely of transgressives of Pinus contorta and Pseudotsuga menziesii which occur aggregated in microhabitats suitable for seedling establishment. Both species are also represented i n the B2 layer but only Pseudotsuga menziesii seedlings are present i n the C layer. The B2 layer i s dominated by Juniperus communis with average species significance of 5.6. This species i s indicative of dry exposed habitats. Other constant shrub species include % Shepherdia canadensis, Rosa acicularis, Amelanchier a l n i f o l i a and Spiraea b e t u l i f o l i a . Arctostaphylos uva-ursi, which i s characteristic of dry forest habitats, i s the most important species of the C layer with an average species significance of 6.7. Carex concinnoides is a constant associate with an average species significance of 3.7. Oryzopsis pungens, Apocynum androsaemifolium, and Artemisia campestris, a l l of which reach their best development on dry exposed sites, are constant species characteristic for the association. Gaillardia aristata although only present with a constancy of class III, i s also 160 considered as characteristic because of i t s exclusiveness for this association. Agropyron spicatum, Achillea millefolium, Allium cernuum, Stipa richardsonii, Arabis h o l b o e l l i i and Festuca saximontana are present because of the rapidly drained so i l s and open tree canopy which provides an exposed habitat. The presence of these species coupled with the absence of Calamagrostis rubescens i s indicative of the dryness of this forest association. Selaginella densa, a characteristic species for the association, dominates the D layer with an average species significance of 4.4. The most significant bryophytes are Tortula ruralis and Ceratodon purpureus with average species significances of 3.4 and 2.7 respectively. Dicranum polysetum and Pleurozium schreberi are present with low significance at the base of woody plants where more moisture i s available. Lichens are more important than bryophytes in this submesic habitat with the dominant species being Cladonia pocillum and C. g r a c i l i s , which have average species significances of 3.6 and 3.3 respectively. The only other constant species are Peltigera malacea and Diploschistes canadensis. Important non-constant species include: Peltigera canina var. rufescens, Cladonia nemoxyna, C. pyxidata, C. mitis, C. chlorophaea and C. rangiferina. The epiphytic growth in this association i s poorly developed probably because of the dry southerly exposures. Alectoria glabra, Cetraria canadensis, Hypogymnia physodes, Letharia vulpina and Parmelia sulcata are the only constant species. A l l studied plots of this association were located north of Williams lake on south exposures. The association also occurs on the Fraser Plateau at low elevations in the major valleys on coarse textured terraces. However, here i t i s on northerly exposures because the general climate i s drier and warmer. 161 Fig. 18. The Arctostaphylo - Junipero - Pseudotsugetum *glaucae showing the characteristic open forest development. This association i s developed on sandy g l a c i a l outwash and i s dominated by Pseudotsuga menziesii, Juniperus communis and Arctostaphylos uva-ursi. Fig. 19. The Calamagrostido - Pseudotsugetum *glaucae calamagrostido -pseudotsugetosum *glaucae showing the excellent development of Pseudotsuga menziesii. The climax stature of this association i s indicated by the abundant Douglas-fir regeneration. Calamagrostis rubescens i s the dominant C layer species. 162 The Arctostaphylo - Junipero - Pseudotsugetum *glaucae has been burned in recent history as evidenced by f i r e scarred trees. The association also has a history of slight grazing which does not appear to have altered the vegetation structure. Calamagrostido (rubescentis) - Pseudotsugion *glaucae 1. Calamagrostido (rubescentis) - Pseudotsugetum *glaucae (ref. Tables; 63, 64, 65, 66, 83, and Fig. 19, 20, 21) Characteristic Combination of Species Order Characteristic Species Pseudotsuga menziesii Arctostaphylos uva-ursi Carex concinnoides Hieracium umbellatum Spiraea b e t u l i f o l i a Dicranum polysetum Cladonia chlorophaea Cladonia g r a c i l i s Cladonia mitis Cladonia rangiferina Peltigera aphthosa Alliance Characteristic Species Aster conspicuus Calamagrostis rubescens Hypnum revolutum Polytrichum juniperinum Rhytidiadelphus triquetrus Association Characteristic Species Astragalus miser Cetraria ericetorum Cladonia cornuta Stereocaulon tomentosum Important Companion Species Rosa acicularis Shepherdia canadensis Solidago multiradiata Lathyrus ochroleucus Vicia americana Anemone multifida Erigeron speciosus 163 63 Plot Data Number of Plots calamagrostido Calamagrostido (rubescentis) pseudotsugetosuin Pseudosugetum "glaucae i contortae Plot No. Plot Size (m2) Date analyzed Elevation (ft) Locality Physiography Landform Relief shape Slope gradient (") Layer coverage (») Aj layer A 2 layer A 3 layer Bj layer B 2 layer C layer D layer Plot coverage (%) Humus and l i t t e r Mineral Soil Decaying wood Soil Nygrotope Trophotope Erosion Drainage Horizon depth (in) L-H 061 400 7/6 1968 006 400 23/6 1967 51*47" 52*25' 122*34' 122*23' 007 400 24/6 1967 S2*25' 122*23' 067 400 25/6 1968 51*46' 122*34' 013 400 3/7 1967 52*26' 122*22' 014 400 5/7 1967 52*26' 122*22' slope bench convex ... .concave. Slope straight convex straight .submesic - mesic .-permesotrophic. n i l well 2-0 1-0 1-0 0-9 0-5 0-4 9-21 5-21 4-29 21-30+ 21-32+ 29-36+ 2-0 0-11 1-0 0-20 1-0 0-19 051 400 18/8 1967 51*46' 122*37' 023 400 22/7 1967 51*43' 122*38' 025 400 23/7 1967 51*43' 122-38' 034 400 31/7 1967 51*47* 122*40' 069 400 1/7 1968 51*48' 122*48' 070 400 2/7 1968 51*48' 122°48' . .concave straight concave f l a t . N NE NW neutral 088 400 26/7 1968 51*43' 122*55' gully gully slope bench Blope ....mesic.... .tnesotrophic. n i l well 2-0 2-0 0-10 0-3 3-15 10-30* 15-27+ 2-0 0-13 13-26 26-36+ 1-0 0-10 10-19 19-32+ 1-0 0-13 1-0 0-7 2-0 0-6 Parent material .glacial d r i f t glacial d r i f t 164 64 Calanagroatldo (rubeacantla) • calamagrostido - peeudotsugatoau* 'glauca* F**udotaug*tua 'olaucae pknetoau* contort O t l 006 007 0(7 0 t l O i l 400 400 400 400 400 400 2SO0 2«50 1*10 3(00 1850 29O0 T 1 • 10 11 12 13 051 021 0JS 034 049 070 O i l 400 400 400 400 400 400 400 1000 1025 JOTS 1120 3400 3400 3*50 Populus tremuloldc* 7 Spiraea b a t u l i f o l l e • Juniperus communis > Aaelanchier • l n i f o t i * 10 Juniperus acopulorun C Layer 11 C a l a n a g r o i t i a rube*cent 1] Arctottaphyloa u v i - u m 13 Astragalus o i l e r 14 Galium boreale t l Solidaqo n u l t i r a d l a t a Pseudotsuga Rieniles i i I t A c h i l l e a a l l l e t o U u * 17 Aster conspicuua I I L i t h y r u t ochroleucus 1* V l e i * amer lean* 20 Anemone n u l t i f i d a 21 Agropyron apicatun Rosa a c i c u l a r i s 32 Fragaria v i r g i n i a n a 23 Hieraciun umbellatum 24 A l t e r c i l i o l a t u a 25 Erigeron apecioaui I t A l l i u a cernuun Pinua contorta 17 Taraaacun o f f i c i n a l * 21 Geranium vlscoslisimum Spiraea b e t u l i f o l k a 39 Care* concinnoides 30 Carea coneinns 31 Antennaria neglect* 32 Antennaria anaphaloidea 33 Antennaria rosea 34 Ceum t r i f l o r urn 35 Arnica c o r d i f o l i a 36 S t i p a r i c h a r d s o n i i 37 pyrole vlrens )• Agoaeria glauca 39 Elynus hirautua 40 LIthaapernun ruderale 41 Mahonla aquifolium 43 v i o l a adune* *1 Agropyron aubsccundun 44 Disporum trachycerpua 45 P o t e n t i l l a pennsylvanlca 4S Linnaea b o r e a l i a 47 Antennaria umbrinelle 41 Oryiopsia pungent 49 Poa i n t e r i o r 50 Ceraetiure arvense 51 Epiloblum anguatifolium S3 Sytnphoricarpos O c c i d e n t * t i l 3) Kauchera c y l i n d r i c a Populus treouloides Juniperua scopuloruai 34 S t i p a Columbiana 5( Dleranum polyaetum 57 Eurhynehium pulchelluai SI Hyloconiun splendcni 59 Rnytldiadelphua t r i q u e t f u s 40 Ceratadon purpureua t l Dicranun fusceacens t l Hypnum revolutum 63 p t i l i u m c r i s t a - c a r t r e n i i * 44"DrepanocIadua uncinatua 13 P o l y t r i c h i a juniperir.ua-t t Tiffenla a u a t r i a c a t7 DicranuB accparium t l Hrachythecium salebroaun 19 Hnium splnulosum 70 T o r t u l a r u r a l i a 71 P e l t i g e r a malacea 72 P e l t i g e r a aphthoae 73 Cladonia g r a c i l i s 74 P e l t i g e r a canina var. .-ufesc 75 Cladonia r e n g i f e r i n a 7t Stereocaulon toaientosujn 77 C e t r a r i a e r i c e t o r u n 71 P e l t i g e r a canina var. canlnj T9 Cladonia cornuta •0 Cladonia mitts I t Cladonia chloropnaea •2 Cladonia pyxidata 13 Cladonia p o c i l l u a i •4 C e t r a r i a c u c u l l e t a IS Cladonia arbuscule I t Cladonia multiformis 17 B a c i d i a aphaeroides I I B l a a t e n i a sinapisperm* •9 Lecidea bcrcngerlana 7.4 fi.l 4.4 1.2 S.4 4.2 4.3 2.2 2.3 3.2 3.2 1.3 1.2 - - 3.1 1.2 3.1 2.3 1.2 1.2 1.2 t . 2 2.2 2.; 4.1 2.1 2.1 S.2 ).t 1.3 1.7 2 2.1 - I.I 2 3.1 2.* i . : * 2.* 1.* 2.' .3 7.4 l . f 3.1 I.* 2.1 2.2 2.2 1.2 7.4 7.3 6.3 3.2 1.1 4.2 1.1 1.1 1.2 1.2 1.2 4.1 1.2 TOTAL SPECIES ( i n c l . aporadics 1 Ac;ropyron trachycaului 1 Agrostis acabra ] Antennaria p a r v l f o l l a I A r m a r i a l a t e r i f l o r a ( Artemisia campestrii S Aater eampeatrla i l l i r a , Epiphyses 1 IS A l a c t o r i a a l a n r * J i t Mypc-jymnla phyaodei 117 L e t h a r i a vi.lplna 111 P a r M l t a Bulcata 119 P i r M l I o p i L i aatilgua 120 P a r M l i o p i l a hyper opt a 12 1 Uanea^labreecene 132 C e t r a r i a canadenal* 12) Arceuthobiuin anarlcanum 124 C e t r a r i a p l n a a t r l 125 C e t r a r i a m e r r e l l l l U t Lecanora v a n a 007(...( 02X1.1) 013(2.1) 025(1.1) 011(1.1) 02SH *) 0)4 I* 02512.11 007(*.•) 070(2.*) 070(1.1) (V) (IV) (111) ( I I I I ( I I I ) I I I I ) 103 ledum stenopataluai 10) Senecio pauperculue 104 S s i l a c l n a a t e l l a t a 105 Anblyetagiuv serpent lOt C e t r a r i a n i v a l i s 107 Cladonia cenotea 101 Cladonia furcata 10* Cladonia scabrluacula 110 Pannaria p e i i i o i d a a 111 P e l t i g e r a venoaa 112 P o h l i a crude 11) P o l y t r i c h i a p i l i f e r u a i 114 M t y t i d l u * rugoau* 131 (Jenaa hkrte 121 A l a c t o r i a ajwrlcen* 129 C e t r a r i a ha l e i 1)0 C e t r a r i a erlcetorvam 1)1 C e t r a r i n qlauca 1)3 Uinea a o r e d i l f e r a D ) A l a c t o r i a glabra 1)4 l u a l l l a punctata IIS HypOvY*>nia v i t t a t a I)« Uanea glebrata 1)7 Uanaa e ^ a b r a t a 1II l a n t h o r l a f a l l a * 0tl(l.») 0 t 7 [ l . l ) 011(1.1) Of7(3.1) 165 Important Companion Species (Cont'd) Allium cernuum Pleurozium schreberi Eurhynchium pulchellum The Calamagrostido-Pseudotsugetum *glaucae i s the most common forest association in the Cariboo Zone being widespread on the Fraser Plateau as well as i n the area north of Williams Lake. It occurs i n shallow gullies, on level benches or on slopes with gentle to moderately steep gradients. Measured slope gradients ranged from 2° to 21° . No specific slope exposure appears to favour the development of this association and a l l exposures were represented by the sampled plots. The surface topography i s varied with convex, concave, straight and f l a t r e l i e f shapes represented. There i s no evidence of surface erosion and the soi l s are rated as being well drained. The hygrotope of this association i s considered to be subhygric up to mesic. The s o i l surface i s covered by a thin layer of l i t t e r varying i n extent from 92% to 98% of the total surface area. Decaying wood was present on a l l plots sampled and a small amount of mineral s o i l was exposed in seven plots. The s o i l i s developed from a parent material of glacial d r i f t and has the following horizon sequence: A thin L-H horizon overlying a brownish coloured B horizon and a light coloured C horizon which in some samples effervesced sl i g h t l y with hydrochloric acid. In some soil s the B horizon is subdivided into a B^ and B 2 horizon. The surface mineral horizon (B^) i s medium textured and composed predominately of s i l t s and sands. The sampled horizons are c l a s s i f i e d as loams, sandy loams, or clay loams. Coarse fragments, mostly of gravel size, are constantly present. In most so i l s the clay content increases with depth and the C horizon i s finer textured. However, in the three plots (067, 013, 014) there was an increase i n sand content, and,„the C horizons were coarser than the corresponding surface horizons. Sampled C horizons have 166 a range of textural classes from sands to s i l t clay loams. Coarse fragments varying in size from gravels to stones were present in a l l samples. The s o i l reaction i s acidic to neutral at the surface and increases in a l k a l i n i t y with depth. Measured pH values for the L-H horizon ranged from 4.7 to 7.1. The B horizon i s weakly acidic to neutral with pH values ranging from 6.0 to 7.3 and the C horizon i s circumneutral to alkaline with pH values ranging from 6.5 to 8.1. The B-^  horizon appears to be enriched with organic matter originating from the L-H horizon. Measured carbon ranges from 2.7% to 9.3% in the B horizon and decreases down the p r o f i l e . Carbon i s generally not detectable i n the C horizon. Total nitrogen i s present in high amounts in the L-H horizon, decreases to moderate concentrations in the B horizon and i s present in low amounts in the C horizon. The carbon:nitrogen ratios are also high in the L-H horizon suggesting that decomposition and n i t r i f i c a t i o n takes place slowly. However, i n the B horizon the carbon:nitrogen ratios are more favourable indicating that nitrogen i s available for plant growth. Available phosphorus i s present in high amounts in the L-H horizon with values ranging from 10% to 32%. It decreases in the mineral s o i l with depth corresponding to the decrease i n organic matter content. Similarly, exchangeable potassium i s present in high concentration in the L-H horizon and decreases in concentration slightly in the mineral s o i l . Exchangeable sodium i s present in low to moderate amounts in a l l horizons but i s slightly higher at the surface. High amounts of exchangeable calcium and magnesium occur in the mineral s o i l with calcium reach-ing a maximum concentration of 16.8 meq/100 g and magnesium a maximum of 10.4 meq/100 g. Calcium i s present in greater concentrations than magnesium and both cations tend to be present in higher amounts in the C horizon than in the B horizon. However, the highest concentrations of calcium are in the L-H horizon where values range from 7.1 meq/100 g to 37 meq/100 g. This i s because the l i t t e r o Table 65 Soil Texture Calamagrostido (rubescentis) - Pseudotsugetum *glaucae calamagrostido - pseudotsugetosum *glaucae pinetosum contortae Number of Plots Plot No. 1 061 2 006 3 007 4 067 5 013 6 014 7 051 8 023 9 025 10 034 11 069 12 070 13 088 Bi Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B2 Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments L 13 50 38 g-SiL 3 61 36 9-SL 13 23 64 L 18 47 35 g-L 13 47 40 SCL 27 24 49 L 20 36 44 g-SCL 31 22 47 g.c.s. g.c.s. SCL 32 25 43 L 17 40 43 g.c. No B 2 LS 0 16 84 SL 11 20 69 No B 2 S 3 3 94 SL 19 28 53 g.c.s. g.c.s. No B 2 S 3 6 92 g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. L 27 31 42 g.c. No B 2 L 23 36 42 L 13 38 49 g-L 23 32 45 L 19 39 42 g.c. SCL 21 28 51 L 27 32 41 SCL 21 25 54 CL 30 36 34 g-CL 28 38 34 g.c.s. g.c.s. g.c. SiCL 34 50 16 SL 8 41 51 NO B 2 L 14 35 51 SL 3 32 65 No B 2 SL 16 30 54 SL 9 30 61 g.c.s. g.c.s. g.c. No B 2 L 23 33 44 g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. g.c.s. 168 B2 Horizon C% N% C/N P ppm Na K Ca Mg CEC pH C Horizon Table 66 S o i l Chemical Analysis Calamagrostido (rubescentis) - Pseudotsugetum *glaucae calamagrostido - pseudotsugetosum 'glaucae pinetosum contortae 5.9 .20 29.5 13.0 .13 .37 6.6 6.6 28.3 6.9 1.8 .11 16.4 6.0 .11 1.10 11.2 5.1 12.0 6.8 .06 3.0 .43 .54 11.7 1.9 12.4 6.5 No B 2 No B 2 No B 2 No B 2 0 .02 0 4.0 .87 4.87 7.5 4.6 18.5 6.8 0 .03 0 6.0 .69 .18 5.0 6.1 21.7 7.5 1.3 .11 11.8 7.0 1.30 .38 7.0 7.4 18.3 7.4 No B 2 No B 2 Number of Plots 1 2 3 4 5 6 7 8 9 10 11 12 13 Plot NO. 061 006 007 067 013 014 051 023 025 034 069 070 088 L-H Horizon C% 46.2 42.8 22.0 45.4 18.4 32.8 21.4 33.4 32.8 32.7 41.6 16.3 . N% 1.64 1.63 .84 1.47 .87 .98 .88 1.07 1.10 .92 1.09 .94 C/N 28.2 26.3 26.2 30.9 21.1 33.5 24.3 31.2 29.8 35.5 38.2 17.3 * P ppm 32.0 31.0 17.0 18.0 13.0 18.0 18.0 10.0 15.0 21.0 12.0 13.0 Data Na .17 .18 .19 .19 1.23 .11 .18 2.78 1.72 1.30 .64 .34 not K 2.36 1.33 1.74 2.26 .65 1.28 6.15 .24 1.03 1.28 1.42 .88 a v a i l Ca 27.8 7.1 18.3 37.0 16.2 20.1 20.5 12.0 22.2 10.0 24.8 26.0 able Mg 12.8 4.8 4.8 6.6 3.0 5.5 7.0 7.0 14.6 5.7 12.8 6.2 . CEC 94.7 88.4 58.7 87.0 39.4 83.7 64.8 63.4 71.8 84.3 72.9 34.7 pH 6.0 6.8 6.7 5.7 7.1 6.6 5.4 , 5.6 4.9 4.7 5.2 5.3 '• Bi Horizon c% 7.1 0 4.8 6.0 0 4.9 2.6 7.5 3.8 3.4 2.7 0 9.3 N% .29 .04 .25 .24 .05 .29 .13 .72 .23 .21 .12 .12 .58 C/N 24.5 0 19.2 25.0 0 16.9 20.0 10.4 16.5 16.2 22.5 0 16.0 P ppm 11.0 7.0 4.0 3.0 4.0 5.0 9.0 16.0 4.0 16.0 16.0 4.0 7.0 Na .08 .09 .09 .11 .13 .88 .09 .69 1.26 1.13 .19 .18 .31 K 1.09 .97 .68 .94 .35 1.18 1.99 2.56 .27 .38 .37 .36 .83 Ca 7.5 7.4 8.0 10.0 4.9 9.4 7.25 10.0 7.0 7.5 8.3 5.5 8.5 Mg 5.7 2.0 2.7 4.1 2.5 3.5 3.5 5.3 6.7 6.6 3.8 2.8 5.8 CEC 32.5 17.4 18.3 18.3 21.2 22.0 16.3 31.0 13.6 21.7 34.6 7.6 36.5 pH 6.8 7.3 6.9 6.8 6.5 6.8 6.2 7.4" 6.9 6.6 6.2 6.0 6.2 No B 2 c% 3 8 0 0 0 0 0 0 0 0 0 1.8 2.6 5.8 N% 16 .03 .04 .13 .05 03 .06 .03 .03 .06 .16 .16 .16 C/N 23 8 0 0 0 0 0 0 0 0 0 11.3 16.3 36.3 P ppm 8 0 2.0 3.0 5.0 5.0 6 0 6.0 6.0 3.0 5.0 7.0 9.0 5.0 Na 31 .12 .50 .12 .28 16 .10 .74 1.13 1.69 .40 .32 .20 K 27 .87 .51 .33 3.13 17 1.73 1.03 .15 .37 .60 .41 1.12 Ca 5 9 9.9 16.8 5.7 3.5 5 9 9.0 10.5 9.0 8.5 7.8 9.1 8.4 Mg 6 7 4.8 1.1 2.7 2.4 2 6 4.9 4.8 5.8 7.0 10.4 8.9 6.9 CEC 18 6 13.5 10.0 4.9 12.2 7 4 22.5 13.5 24.8 9.8 23.1 20.5 19.9 pH 7 3 7.0 6.5 7.0 6.7 7 4 6.8 8.1 8.0 8.0 7.5 6.5 7.1 169 Pseudotsuga menziesii i s rich in calcium (Daubenmire 1953). The high concentrations of calcium and magnesium i n the mineral s o i l may in part account for the alkaline reaction of the C horizon. The cation exchange capacity of the L-H horizon i s very high with values ranging from 34.7 meg/100 g to 94.7 meg/100 g. It decreases in the mineral s o i l but i s s t i l l high because the s o i l has a high clay content. Cation exchange capacity ranges from 7.6 meg/100 g to 36.5 meg/100 g in the B horizon and 4.9 meg/100 g to 24.8 meg/100 g i n the C horizon. These soils are considered to be edaphically rich and the association i s rated as mesotrophic to permesotrophic. The soi l s of this association are classed as Orthic Brown Wooded soils because they have an L-H horizon, a brownish B horizon and a weakly acidic to alkaline s o i l reaction. c Structurally, the association consists of four vegetation l a y e r s — a well developed tree layer, a poorly developed shrub layer, a well developed herb layer and a well developed bryophyte and lichen layer. The tree layer has three sublayers of which the A2 is the best developed. Pseudotsuga menziesii i s the only constant tree species. The shrub layer consists of two sublayers. The B^ i s composed entirely of tree transgressives of which Pseudotsuga menziesii i s the most common species. The layer i s dominated by Rosa acicularis with an average species significance of 2.5. Shepherdia canadensis, Juniperus communis, Amelanchier a l n i f o l i a and Juniperus scopulorum are a l l present as non-constant species with lower significances. Symphoricarpos occidentalis, which has a constancy of class III, i s indicative of the permesotrophic habitat. The herb layer (C) has a percentage cover ranging from 42% to 90%. It i s dominated by Calamagrostis rubescens with an average species significance of 6.9 and Arctostaphylos uva-ursi with an average species significance of 3.3. 170 Astragalus miser, which i s characteristic of this association i s a constant associate with an average species significance of 2.6. Galium boreale, Solidago multiradiata, Achillea millefolium, Aster conspicuus and Pseudotsuga  menziesii (as seedlings) are the only other constant species of the C layer. The presence of Agropyron spicatum, Cerastium arvense, and Heuchera cylindrica i s indicative of the grassland influence on this forest association. Non-constant C layer species important in the characterization of this association include: Lathyrus ochroleucus, V i c i a americana, Anemone multifida, Fragaria  virginiana, Hieracium umbellatum, Erigeron speciosus and Allium cernuum. The bryophyte and lichen layer (D) varies from poorly developed to well developed as indicated by i t s percentage cover which ranges from 5% to 72%. The constant bryophyte species are: Pleurozium schreberi, Dicranum  polysetum, Eurhynchium pulchellum. Important non-constant species include: Hylocomium splendens, Rhytidiadelphus triquetrus, Ceratodon purpureus, Dicranum  fuscescens and Hypnum revolutum. Lichens are less important in the structure of the D layer than are bryophytes and no constant species are present. Common species of constancy class IV include: Peltigera malacea, P. aphthosa, Cladonia g r a c i l i s , Peltigera  canina var. rufescens and Cladonia rangiferina. Stereocaulon tomentosum, Cetraria ericetorum and Cladonia cornuta, although present with low constancy, are considered as characteristic species of the association. The epiphytic flora i s moderately well developed and the constant species are: Alectoria glabra, Hypogymnia physodes, Letharia vulpina, Parmelia  sulcata, Parmeliopsis ambigua, Parmeliopsis hyperopta and Usnea glabrescens. The Clamagrostido - Pseudotsugetum *glaucae i s used primarily for logging as these sites are very productive for Douglas—fir. It i s grazed only l i g h t l y because Calamagrostis rubescens appears to have a low p a l a t i b i l i t y for cattle. 171 The Calamagrostido - Pseudotsugetum *glaucae i s divided into two subassociations which are: (1) the calamagrostido - pseudotsugetosum *glaucae and (2) the pinetosum contortae. These are differentiated on the basis of species composition of the tree layer, minor f l o r i s t i c differences of the B and C layers and small habitat differences. Calamagrostido (rubescentis) - Pseudotsugetum *glaucae 1. calamagrostido (rubescentis) - pseudotsugetosum *glaucae (ref. Fig. 19) Differential Species Spiraea b e t u l i f o l i a Carex concinnoides This i s the drier of the two subassociations and i s rated as mesic. It reaches best development on exposed slopes at low elevations. It i s most common north of Williams Lake, in the continuous forest area, where i t occurs usually on southerly exposures. Snow accumulation i s low and snow duration short in this subassociation with most sites being snow free by mid-April. The s o i l reaction has a narrower range than that described for the association. The L-H horizon i s weakly acidic to neutral with pH values ranging from 6.0 to 7.1. The B and C horizons are circumneutral with pH ranges of 6.5 and 7.3 and 6.5 to 7.4 respectively. This and the drier hygrotope appear to be the only edaphic conditions which differentiate the calamagrostido - pseudotsugetosum *glaucae. F l o r i s t i c a l l y , the calamagrostido - pseudotsugetosum *glaucae i s differentiated by the presence of Spiraea b e t u l i f o l i a with an average species significance of 2.7 and Carex concinnoides with an average species significance of 2.3. Antennaria neglecta, Elymus hirsutus, Mahonia aquifolium and Disporum  trachycarpum are present in the Calamagrostido - Pseudotsugetum *glaucae only in this subassociation but with low constancy and significance. 172 The subassociation i s dominated by Pseudotsuga menziesii which occurs in the A,B, and C layers. It i s the only tree species present and forms an open canopy. Rosa acicularis dominates the shrub layer with an average species significance of 1.7 but i s less important here than in the pinetosum contortae. The drier habitat i s reflected i n the poorer development of the C layer which has a percentage cover ranging from 42% to 78%. Clamagrostis  rubescens i s the dominant species with an average species significance of 6.0 which i s considerably lower than i t s rating in the pinetosum contortae. Similarly because of the drier habitat and low degree of shade the D layer i s less well developed than i t s counterpart i n the pinetosum contortae Pleurozium schreberi i s the dominant species but with a lower species significance than in the pinetosum contortae. Lichens are more abundant in this subassociation with Peltigera malacea, and Peltigera canina var. rufescens being the most important species. The calamagrostido - pseudotsugetosum *glaucae i s considered to be in climax state and appears to be represented by two varieties of different hygrotopes although these were not distinguished i n this study. The sub-association described here represents the drier variety which i s developed at low elevations on exposed slopes. The second variety develops i n the Cariboo Zone at higher elevations (over 3000 ft) and i s common throughout the Douglas-f i r Zone. Here a cooler moister climate prevails which w i l l produce a moister hygrotope. Of the sampled plots, 061 and 067 most closely approximate this moist variety as they occur on north exposures, have more acidic surface s o i l reactions and have well developed bryophyte and lichen layers with Pleurozium  schreberi reaching a species significance of 6 and 7 respectively. This subassociation appears to have been burned in recent history based on the presence of f i r e scarred trees. Following f i r e , regeneration i s 173 considered to be by Pseudotsuga menziesii, because at the low elevations where this subassociation develops, Pinus contorta appears unable to compete successfully for control of the edaphically rich, dry sites. However, in the moist variety mentioned above, regeneration following f i r e would probably be by Pinus contorta as this species i s more common in the higher elevations where i t i s established quickly on newly available sites. Calamagrostido (rubescentis) - Pseudotsugetum *glaucae 2. pinetosum contortae (ref. Fig. 20 and 21) Differential Species Pinus contorta Geranium viscosissimum Carex concinna Geum triflorum Linnaea borealis Populus tremuloides Epilobium angustifolium The pinetosum contortae i s considered as a moister subassociation and i s rated as mesic. It is most common on the Fraser Plateau and i s best developed at higher elevations where the climate i s cooler. Sampled plots ranged in elevation from 3000 feet to 3650 feet. It i s formed on slopes and gullies with northerly exposures or on level benches. Snow duration i s longer than in the calamagrostido - pseudotsugetosum *glaucae. The sites may also benefit from seepage i n the early spring. The s o i l reaction of the L-H and B horizons is more acidic than in the calamagrostido -pseudotsugetosum *glaucae but the C horizon has a similar circumneutral to alkaline reaction. Measured pH values of the L-H horizon range from 4.7 to 5.4 and pH values of the B horizon range from 6.0 to 7.4. The lower surface pH values are thought to result from the l i t t e r of Pinus contorta which i s more acidic than that of Pseudotsuga menziesii. F l o r i s t i c a l l y , this subassociation i s differentiated largely on the 174 Fig, 20. The Calamagrostido - Pseudotsugetum *glaucae pinetosum contortae showing the typical high stem density of generally even-aged lodgepole pine trees. Standing dead trees are common in this subassociation and can be seen on the l e f t of the picture. The subassociation has a well developed herb layer (C) dominated by Calamagrostis rubescens. Fig. 21. The Calamagrostido - Pseudotsugetum *glaucae pinetosum contortae with a well developed understory of Pseudotsuga  menziesii. It w i l l eventually dominate this forest because of i t s shade tolerance and the pinetosum contortae w i l l advance, successionally, to the calamagrotido -pseudotsugetosum *glaucae. 175 constant presence of Pinus contorta which occurs as the dominant tree species. It forms an almost closed canopy with species significances ranging from 5 to 7. Pseudotsuga menziesii i s less important in this subassociation and reaches i t s best development as an understory tree i n the A^ layer. However, Pseudotsuga menziesii transgressives and seedlings are constantly present in the subordinate vegetation layers. Populus tremuloides is present in the tree and shrub layers of this subassociation and i s indicative of the moist conditions. Rosa acicularis i s the dominant shrub species, as i n the calamagrostido - pseudotsugetosum *glaucae, but occurs here with an average species significance of 3.1. Because of the moister hygrotope the C layer i s better developed in this subassociation, with a percentage cover ranging from 63% to 90%. Calamagrostis rubescens i s again the dominant species but occurs here with a higher species significance of 7.7. Geranium viscosissimum, and Geum triflorum are represented in the Clamagrostido - Pseudotsugetum *glaucae only i n this subassociation. Similarly, Linnaea borealis and Epilobium angustifolium are present only here and are considered to be good indicators of the moister conditions that prevail. Antennaria rosea, Stipa richardsonii, Agropyron  subsecundum, Potentilla pennsylvanica and Stipa Columbiana are present i n the pinetosum contortae because of the close proximity of communities of the Stipion columbianae. The bryophyte and lichen layer i s better developed i n this subassociation because of the moister habitat, acidic s o i l surface and higher degree of shade. The most important species are Pleurozium schreberi, Dicranum polysetum and Eurhynchium pulchellum. This subassociation i s considered to be of successional status as the dominant Pinus contorta w i l l eventually be replaced by the more shade tolerant Pseudotsuga menziesii which now occurs as an understory species (Fig. 21). Succession w i l l terminate in a climax community of the moist variety 176 of the calamagrostido - pseudotsugetosum *glaucae because of the cooler climate which prevails in the area now occupied by the pinetosum contortae. The pinetosum contortae i s considered to be strongly affected by f i r e as old charred logs are often present on the s o i l surface and some of the older trees are f i r e scarred. This subassociation i s regarded to be maintained by repeated burning as Pinus contorta appears to be shade intolerant on these moist sites and thus requires open sites for establishment and survival. At these higher elevations colonization of new areas i s by Pinus contorta as Douglas-fir does not seem to be able to compete successfully here, for space, in the early stages of succession. 2. Rhytidiadelpho (triquetri) - Pleurozio (schreberi) - Pseudotsugetum *glaucae (ref. Tables; 67, 68, 69, 70, 83, and Fig. 22) Characteristic Combination of Species Order Characteristic Species Pseudotsuga menziesii Carex concinnoides Arctostaphylos uva-ursi Hieracium umbellatum Spiraea b e t u l i f o l i a Dicranum polyseturn Cladonia chlorophaea Cladonia g r a c i l i s Cladonia mitis Cladonia rangiferina Peltigera aphthosa Alliance Characteristic Species Aster conspicuus Calamagrostis rubescens Hypnum revolutum Polytrichum juniperinum Rhytidiadelphus triquetrus Association Characteristic Species Acer glabrum Betula papyrifera Aralia nudicaulis Arnica co r d i f o l i a Calypso bulbosa 177 Association Characteristic Species (Cont'd) Clematis columbiana Disporum trachycarpum Goodyera oblongifolia Habenaria obtusata Lathyrus nevadensis Oryzopsis asperifolia Pyrola virens Smilacina racemosa Timmia austriaca Mnium spinulosum Important Companion Species Rosa acicularis Shepherdia canadensis Pleurozium schreberi The Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae i s formed on the lower parts of steep slopes or i n gul l i e s , some of which appear to be old stream courses. The surface topography i s generally concave. The slopes are moderately steep and have either north or northeast exposures. Measured slope gradients range from 17° to 29°. The consistent northerly exposures allow a cool moist microclimate to develop. These sites have a long snow duration with snow being observed to be present past the beginning of May. Over 90% of the s o i l surface i s covered by a thick layer of l i t t e r composed largely of dead bryophytes. This l i t t e r layer w i l l effectively decrease moisture loss from the s o i l as a result of evaporation. In a l l sampled plots a small amount of decaying wood was present on the s o i l surface. There i s no evidence of surface erosion and the soils are judged to be moderately well drained. The association i s considered to benefit from temporary seepage because of i t s topographic position. Hygrotopically, this association i s rated as subhygric. The parent material i s g l a c i a l d r i f t i n a l l plots except plots 005 and 015 where the parent material i s alluvium. With the exception of plot 015 the s o i l consists of a thin L-H horizon, a brownish coloured B. horizon (in 178 Table 67 Plot Data Number of Plots Plot No. Plot Size (m2) Date analyzed Elevation (ft) Locality Physiography Landform Relief shape Exposure Slope gradient (") Layer coverage (%) Aj layer A2 layer A3 layer Bi layer B 2 layer C layer D layer Plot coverage (%) Humus and l i t t e r Mineral s o i l Decaying wood Soil Hygrotope Trophotope Erosion Drainage Horizon depth (in) L-H Bl B 2 C Parent material Rhytidiadelpho (triquetri) Pleurozio (schreberi) -Pseudotsugetum *glaucae Pleurozio - Vaccinio Piceetum glaucae 1 2 3 4 5 6 7 002 003 004 008 005 015 020 400 400 400 400 400 400 400 16/6 18/6 20/6 26/6 22/6 6/7 18/7 1967 1967 1967 1967 1967 1967 1967 2550 2600 2650 2800 2850 2950 2800 WL WL WL WL WL WL WL 5 2 ° 1 7 ' 52 0 19' 52 0 14' 5 2 o 2 2 . 5 2 ° 2 4 ' 52 0 26' 5 2 ° 1 3 ' 1 2 2 ° 1 4 ' 1 2 2 ° 1 4 ' 1 2 2 ° 2 2 ' 12Z0\T 1 2 2 ° 2 2 ' 1 2 2 ° 2 2 ' 1 2 2 ° 1 3 base of gully base of head of gully stream slope slope stream course terrac< NE NE N NE NE N NE 18 24 17 24 28 29 9 23 38 22 21 31 13 2 3 4 24 28 15 18 21 5 1 16 16 5 3 32 10 7 3 8 2 11 12 18 12 2 2 2 26 8 63 60 9 11 9 32 76 60 58 84 83 68 66 82 93 95 94 96 91 94 88 2 1 1 1 1 - -5 4 5 3 8 6 12 hygric permesotrophic n i l well sub-mesotrophic 2-0 0-30 30-45+ 1-0 0-24 1-0 0-17 24-46+ 17-34+ . glacial d r i f t . Regosol 1-0 1-0 2-0 0-7 0-12 0-6 7-26 12-21 12-18 26-34+ 21-39+ 24-36+ alluvium a l l u -over vium glacial d r i f t moderate L-H 2-0 Ae 0-5 B 5-12 C 12-25+ alluvium over glacial d r i f t 68 Rhytidiadelpho ( t r l q u e t r l ) - TlrrrtUO (auatrlacae) -pseudotsugetum *glaucae Pleurozio - v a c c l n l o Piceetum glaucae Number of P l o t * Plot No. Plot Size (m1) Elevation (ft) 002 003 400 400 2550 2600 004 400 26S0 001 400 2800 0 0 5 400 2850 015 400 2950 020 400 2800 A Layer 1 Pseudotsuga menziesii 2 Pinus contorta 3 Picca glauca 4 Betula p a p y r i f c r a B Layer Pseudotsuga menziesii 5 Rosa a c i c u l a r i s 6 Shepherdi« canadensis 7 Spiraea b e t u l l f o l i a 8 Acer glabrum Betula papyrifera 10 Symphoricarpos o c c l d e n t a l i s 0.7 0.2 0.5 0.7 0.7 0.3 2.2 0.6 2.5 0.2 0.2 0.4 11 Linnaea b o r e a l i s 12 Calamagrostis rubcscens 13 Pyrola virens Spiraea b c t u l i f o l i a 14 Arnica c o r d i f o l i a Rosa a c i c u l a r i s 15 Disporum trachycarpum 16 Clematis Columbians 17 Fragaria v i r g i n i a n a Pseudotsuga menziesii 18 Pyrola secunda 19 A r a l i a n u d i c a u l i s 20 Aster conapicuus 21 Oryzopais a s p e r i f o l i a 22 Carex concinnoidea 23 Galium boreale 24 Smilacina racemosa 25 Habenaria obtusata 26 Lathyrus ochroleucus Acer glabrum Anelanchier a l n i f o l i * 27 Lathyrua nevadensia 28 Coodyera o b l o n g i f o l i a Picea glauca 29 Rubus idaeus 30 Calypso bulboaa 31 Epilobium angustifolium Shepherdia canadensis 32 Mahonia aquifolium 33 Cornua canadensis 34 Ribea oxyacanthoidea 35 Arctostaphylos uva-ursi 36 Chimaphila umbellota 37 Astragalus miser 38 A c h i l l e a m i l l e f o l i u m 39 Moneses u n i f l o r a 40 Oamorhiza depauperate 41 Smilacina s t e l l a t e 42 V i c i a Americana 43 V i o l a adunca 44 Carex concinna 45 Epilobium wotaonii 46 Galium t r i florum 47 Liliutr. columbiana Betula pap y r i f e r a £ Layer (Bryophytes) 48 Plcuroiium schrebcri 49 Hylocomium splcndens 50 Rhytidiadclphus tr i g u e t r u s 51 Dicranum polysetum 52 Eurhynchium pulchellum 53 P t i l i u m c r i s t a - c a s t r c n a i a 54 Timnia auatriaca 55 Mnium spinulosum 56 Dicranum fuscescena 57 Polytrichum juniperirum SB Hypnum revolutum 59 Dicranum scoparium 60 Drepanocladus uncinatua (Lichens) 61 P e l t i g e r a aphthosa 62 P e l t i g e r a canina var. rufesi 63 Cladonia mi t i s 64 Cladonia g r a c i l i s 65 Cladonia r a n g i f e r i n a 66 PcItigora canina va 67 P e l t i g e r a malacea 6B Lecidea berengerian 69 P e l t i g e r a lepidopho 2.2 2.1 5.2 4.3 3.2 3.2 2.1 1.1 2.5 2.0 2.0 1.7 1.7 1.0 3.0 2.2 l . B 0.9 0.6 0.8 0.8 0.5 0.5 0.4 0.3 0.3 0.3 1.3 0.B 0,7 0.5 0.5 0.4 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 5.9 5.0 4.2 4.0 2.3 2.2 2.6 0.4 0.5 0.5 0.5 0.5 0.5 0.5 TOTAL SPECIES U n c i , sporadical 54 54 49 36 40 44 47_ Sporadic species B Layer 70 Juniperus communis 0 1 5 ( 3 3] 71 Ribes l a c u s t r c 0 1 5 ( 4 2) C Layer 0 Layer 72 Antennaria neglccta 0 0 2 ( 2 2) 82 Cladonia chlorophaea 0 0 8 ( 2 . 1 ) 73 Aquilegia formosa 0081 + + ) 83 Cladonia l u r c a t a 0 0 3 ( 1 . + ) 74 Aster c i l i o l a t u s 0 0 3 1 * + ); 0 2 0 ( 1 . * ) 84 Cladonia poci Hum 0 0 2 ( 1 . * ) 75 Coodyera repens 0 0 2 ( 1 + ) 85 Nephroma hie 1 vet i cum 0 0 4 ( 1 . + ) 76 Hicracium unbellatum 0 0 3 ( 1 •1 86 P e l t i g e r a hori z o n t a l i s 0 0 8 ( 2 . 1 ) 77 M i t e l l a nuda 004<* • I 87 P e l t i g e r a polydactyla 0 0 2 ( 1 . * ) 78 Polyatichum muni turn 0 0 4 1 * •1 B8 Pohlia cruda 0 0 5 ( * . » ) 79 T h c l y p t c r i s orcopter 0 0 4 ( 1 11 B9 Pohlia nutans 002 (-». + ) 80 T r i f o l i u m repens 0031 + + ) 90 Stereocaulon tomentosura 0 0 4 ( * . + ) 81 Vaccinium mcmbranaeeum 004 (1 1)1 0 2 0 ( 2 . 2 ) Epiphytes 91 C e t r a r i a canadcr.if i s (V) 100 Hypogymnia enteromorpha (IV) 109 Basidia sphaeroldea (II) 92 C e t r a r i a h a l e i 101 A l e c t o r l a fremontii (III) 110 C a n d e l l a r i a concolor (11) 93 C e t r a r i a p i n a s t r i (V) 102 A l e c t o r l a glabra (III) 111 Lecanor* cadubriae (II) 94 llypogyfnn ia phyaodea (V| 101 A l e c t o r i a Barmentoaa (III) 112 Uanea glabrescens (III 95 Lethar I J v u lpi na (V) 104 C e t r a r i a glauca (IIII 111 A l e c t o r i a anwjricana (II 96 Parmelis suIcata (V) 105 C e t r a r i a scutata (IIII 114 Brachytheeiurn salebrosum (I) 97 Parme 1 lop* i s ambiqua (V) 106 Cladonia coniocraea (III) 115 B u e l l i a punctata (I) 98 Usnea h i r t a (IV) 107 Parme1iops i a hyperopta (III) 116 Eurhynchium pulchellum (II 99 Uanea s o r e d i i f e r a (IV) 108 P t i l i d i u m pulcherrimum (III) 117 Hypogyauiia v i t t a t a (I) Specie* exclusive to 020 11B Ccocaulon 1ividum 3 1 121 Lyenpodium complunatua 3.1 124 Viburnuai edul* 1.* 119 Habenaria o r b i c u l a t * 1 * 122 Vaccinium cacspltoaun 4.2 125 Populus tranuloldea 120 Lycopodjum annotinum ' i 1 123 Vaccinium n y r t i l l o l d e s 5.2 180 plots 008 and 005 there i s also a horizon), and a light coloured C horizon. The s o i l of plot 015 has a thin L-H horizon overlying an undifferentiated mineral sodium. The surface horizons are medium to coarse textured and range from loamy sands to loams. The sand content increases with depth and sampled C horizons are c l a s s i f i e d as sands, loamy sands or sandy loams. Coarse fragments ranging from gravels to stones are present i n both the B and C horizons of a l l plots except 005 and 015. In these plots coarse fragments are not present in the surface horizon. The coarse fragments collected are mostly cherts, quartzites, and shales belonging to the Cache Creek Group (geological formation Tipper 1959) but there are also a few volcanic tuffs, cinders and lavas present. The reaction of the L-H horizon i s acidic with measured pH values ranging from 5.4 to 6.6. The s o i l reaction becomes neutral to alkaline with depth and pH values of the C horizon range up to 8.2. However, plots 004 and 005 have weakly acidic C horizons with pH values of 6.1 and 6.6 respectively. The range of pH i n the subsurface soi l s i s considered to be related directly to the composition of the parent material as determined from the coarse fragments. Cherts for example w i l l weather out sli g h t l y acidic whereas lavas are more l i k e l y to form alkaline s o i l s . Exchangeable magnesium i s present i n very low amounts but increases sl i g h t l y with depth. These low concentrations suggest that the parent rock had a low magnesium content. Exchangeable calcium i s present i n the L-H horizon i n high concentrations because of the large amount of calcium present in the l i t t e r of Pseudotsuga menziesii (Daubenmire 1953). It i s present i n moderately high amounts in the mineral s o i l and reaches a maximum in the C horizon where measured concentrations range from 4.0 to 10.9 mecr/100 g. The dominance of the exchange capacity by calcium may p a r t i a l l y account for the neutral to alkaline reaction of the mineral s o i l . Available phosphorus i s Rhytidiadelpho (triquetri) Table & Soil Texture - Pleurozio (schreberi) - Pseudotsugetum *glaucae Number of Plots Plot No. 1 002 2 003 3 004 4 008 5 005 Pleurozio - Vaccinio Piceetum glaucae 6 7 015 020 B, Horizon Ae Horizon Textural class SL SL SiL LS SL L SL Clay (%) 13 14 12 10 9 18 10 S i l t (%) 14 26 51 10 39 39 26 Sand (%) 73 60 37 80 52 43 64 Coarse fragments g .c.s. g.c.s. g .c.s g.c.s. None None None. B 2 Horizon B Horizor Textural class No LS SL L L Clay (%) 10 15 13 11 S i l t (%) B 2 6 29 41 42 Sand (%) 84 56 46 47 Coarse fragments s e n t g.c.s. g- None None C Horizon C Horizor Textural class LS SL SL S LS - CL Clay (%) 12 18 15 6 10 Data 29 S i l t (%) 9 24 21 3 8 not 38 Sand (%) 79 58 64 91 82 available 33 Coarse fragments g .c.s. g.c.s. g .c.s. g.c.s. g.c.s. g.c. g. Table 70 S o i l Chemical Analysis Rhytidiadelpho (triquetri) -Pleurozio (schreberi) - Pseudotsugetum *glaucae Vaccinio - Pleurozio Piceetum glaucae Number of Plots 1 2 3 4 5 6 7 Plot No. 002 003 004 008 005 015 020 L-H Horizon L-H Horizon C» 11.9 13.1 28.4 39.1 37.0 41.7 43.7 N% .64 .43 1 .06 1.30 1.26 1.29 1.31 C/N 18.6 30.5 26.8 30.1 29.4 32.3 33.4 P ppm 20.0 16.0 16.0 18.0 26.0 27.0 17.0 Na .18 .18 .19 .77 .20 .37 4.77 K .39 .93 1.18 1.52 1.03 1.23 2.46 Ca 11.4 13.8 23.8 12.5 17.3 21.1 17.8 Mg 1.8 1.7 3.13 3.9 2.5 6.17 2.5 CEC 28.5 22.2 46.9 83.5 67.5 126.1 pH 5.7 6.6 6.0 6.4 5.4 5.6 6.1 Bx Horizon Ae Horizon C* 0 1.1 0 2.3 .8 11.0 4.0 N% .02 .10 .02 .14 .09 .63 .27 C/N 0 11.0 0 16.4 20.0 17.5 14.8 P ppm 9.0 8.0 3.0 7.0 6.0 13.0 4.0 Na .09 .08 .09 .08 .42 .50 1.01 K .09 .25 .51 .38 .46 .65 .24 Ca 5.5 5.5 4.7 5.3 5.5 14.8 3.6 Mg .7 .82 1.15 .82 2.9 6.13 2.5 CEC 16.3 7.8 12.5 16.1 13.9 32.7 18.3 pH 7.S 6.7 6.3 7.0 5.5 6.1 6.3 B2 Horizon B2 Horizon c% 0 0 1.3 0 N% .03 .04 .14 .06 C/N 0 0 9.3 0 P ppm 3.0 6.0 8.0 3.0 Na No No No .09 .37 .53 1.59 K B2 B2 B2 .10 .14 .11 .22 Ca 3.2 3.2 10.9 4.7 Mg .52 1.8 7.5 3.8 CEC 8.4 16.4 16.8 16.5 pH 7.2 5.2 7.0 6.7 C Horizon C Horizon c% 0 0 0 0 0 1.8 0 N% .05 .04 .02 .06 .06 .10 .04 C/N 0 0 0 0 0 18.0 0 P ppm 7.0 4.0 5.0 5.0 4.0 8.0 6.0 Na .08 .09 .44 .08 .47 .43 .49 K .06 .19 .29 .04 .59 .07 .26 Ca 10.9 4.0 6.9 6.9 5.8 10.8 6.8 Mg .8 1.3 4.25 .48 4.8 8.2 3.8 CEC 6.9 4.3 10.0 6.3 8.9 13.6 9.3 PH 8.2 7.0 6.1 8.2 6.6 7.3 7.5 183 present i n high concentrations in the L-H horizon and decreases to moderate amounts in the mineral s o i l . Similarly, the highest concentrations of exchangeable potassium are in the l i t t e r layer and potassium decreases i n concentration with depth. Exchangeable sodium i s present in low amounts i n a l l horizons. The carbon content of the surface mineral horizon i s low and measureable carbon i s present in the C horizon of only plot 015. The low carbon concentration suggests that the addition of organic matter to the s o i l from decomposing l i t t e r and roots occurs slowly. Consequently, total nitrogen i s present in low amounts in the mineral s o i l . Nitrogen i s present i n high amounts in the L-H horizon but the carbon:nitrogen ratios are also high indicating that the organic matter does not contain sufficient nitrogen for decomposition and thus release of nutrients from the l i t t e r w i l l occur slowly. The cation exchange capacity i s high i n the L-H horizon but decreases sharply with depth in the mineral s o i l corresponding to the increasing coarseness of the s o i l . The Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae i s considered to be permesotrophic. Based on the presence of the L-H horizon, the brownish B horizon and the weakly acidic to alkaline s o i l reaction these soi l s are cla s s i f i e d into the Orthic Brown Wooded Subgroup with the exception of plot 015 which i s cla s s i f i e d as an Orthic Regosol. Structurally the association has four recognizable vegetation layers. The tree layer i s represented by a well developed A^ layer with a percentage cover ranging from 13% to 38%, a less well developed ^ layer with a coverage ranging from 3% to 28% and a poorly developed A^ layer with a cover ranging from 1% to 16%. Pseudotsuga menziesii i s the dominant species in a l l layers with species significances up to 7. It forms a moderately closed canopy thus creating habitat of heavy shade. Pinus contorta occurs in the A and A layers but with 184 low constancy and significance. Picea glauca i s present in the tree layer of only two plots but i s present i n a l l three sublayers. The only other tree species present i s Betula papyrifera which occurs i n only one plot with a significance of 2. The shrub layer consists of a high shrub (B^) and a low shrub (B2) layer neither of which is well developed. The B^ layer i s composed largely of tree transgressives of which Pseudotsuga menziesii i s the dominant, followed by Picea glauca with a constancy of class IV. Acer glabrum i s the most important shrub species of this layer. In the B^ layer, Rosa acicularis, Shepherdia canadensis, and Spiraea  b e t u l i f o l i a are the only constant species. Important non-constants include: Acer glabrum, Amelanchier a l n i f o l i a , and Symphoricarpos occidentalis. The only tree transgressives present are those of Pseudotsuga menziesii and Betula papyrifera, both with low significance. The herb and dwarf shrub layer, (C), because of the heavily shaded habitat ranges from poorly to moderately well developed with percentage cover ranging from 9% to 63%. Linnaea borealis dominates the C layer with an average species significance of 2.5. Other constant species characteristic of cool moist forest habitats include: Disporum trachycarpum, Pyrola virens, Arnica  cor d i f o l i a , Clematis Columbiana and Pyrola secunda. Common species present with low significance but important i n the characterization of the association are: Aster conspicuus, Oryzopsis asperifolia, Carex concinnoides, Smilacina racemosa, Habenaria obtusata, Lathyrus ochroleucus, Lathyrus nevadensis, Goodyera  oblongifolia, Calypso bulbosa, and Aralia nudicaulis. The bryophyte and lichen layer (D) i s well developed with a percentage cover ranging from 58% to 84%. Bryophytes are more common than lichens in this moist habitat. Pleurozium schreberi and Hylocomium splendens are constant dominants of the D layer with average species significances of 5.9 and 5.0 185 Fig. 22. The Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae formed near the base of a north facing slope which has temporary seepage. The association i s dominated by Pseudotsuga menziesii and has a very well developed bryophyte layer (D). Fig. 23. The Pleurozio - Vaccinio - Piceetum glaucae formed on fine textured alluvium of an old stream terrace. It i s dominated by Picea glauca and has a very well developed bryophyte layer (D) in which Pleurozium schreberi is the most abundant species. This association is rare in the Cariboo Zone and i t s development i s controlled by edaphic and topographic factors. 186 respectively. Rhytidiadelphus triquetrus and Timmia austriaca, both constant species, indicate that the surface s o i l reaction i s alkaline to only sli g h t l y acidic as neither can tolerate highly acidic conditions. Other constant species include: Dicranum polysetum, Eurhynchium pulchellum, Ptilium crista-castrensis, and Mnium spinulosum. Peltigera aphthosa and Peltigera canina var. rufescens are the only constant lichen species with average species significances of 2.3 and 1.5 respectively. The epiphytic flora i s well developed with the constant species being: Cetraria canadensis, Cetraria halei, Cetraria pinastri, Hypogymnia  physodes, Letharia vulpina, Parmelia sulcata and Parmeliopsis ambigua. The Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae appears to have a history involving f i r e as evidenced by the presence of charcoal i n the s o i l and f i r e scars on the older trees. The effects of grazing are negligible i n this association. A l l studied plots of this association were located north of Williams Lake as the association i s rare and very localized on the Fraser Plateau. Here i t occurs at high elevations on very steep valley slopes with northerly exposures. Piceetalia glaucae The Piceetalia glaucae i s only marginally present in the Cariboo Zone and i s known to occur more extensively in the northern regions of Br i t i s h Columbia which have a cooler more moist climate. In the Cariboo Zone i t occurs on subhygric to subhydric habitats which range trophically from permesotrophic to subeutrophic. This order i s characterized by Picea glauca, Salix bebbiana, Agoseris glauca, Aster c i l i o l a t u s , Delphinium brownii, Epilobium angustifolium, Peasites v i t i f o l i u s , Pyrola secunda, Silene menziesii, Smilacina s t e l l a t a , 187 Thalictrum occidentale and Drepanocladus uncinatus. The Piceetalia glaucae includes three alliances—the Poo -Calamagrostido - Populion,tremuloidis, the Carico - Piceion glaucae and the Equiseto - Piceion glaucae. Each alliance i s represented by a single association. The Pleurozio - Vaccinio - Piceetum glaucae, i s also included into this order. However, because i t i s represented here by only one plot,comparison between i t and other associations of the Piceetalia glaucae are not made. Pleurozio (schreberi) - Vaccinio (myrtilloidis) Piceetum glaucae (ref. Tables; 67, 68, 69, 70, and Fig. 23) This association i s represented only by plot 020. It i s considered to be an association more common i n the Boreal Zone. In the Cariboo Zone i t shows a close f l o r i s t i c similarity to the Rhytidiadelpho - Pleurozio -Pseudotsugetum *glaucae. Plot 020 was located on an old stream terrace at the base of a slope in a narrow valley. The valley i s considered to act as a cold a i r drainage pathway. The terrace has a slope gradient of 9° and a northeast exposure. Because of the topography, a microclimate cooler and moister than those of the surrounding areas has developed here. The habitat has a long snow duration with snow being observed to be present u n t i l near the beginning of June. Soil drainage i s moderate and the association i s believed to benefit from temporary seepage. The hygrotope i s rated as subhygric. The s o i l i s cl a s s i f i e d into the Podzolic Order and has an Ae,B,C, horizon sequence. It i s developed from a parent material of alluvium overlying gravelly g l a c i a l outwash. Texturally, the Ae horizon i s cl a s s i f i e d as a sandy loam, the B horizon as a loam and the C as a clay loam. Coarse fragments of gravel size are present only in the C horizon. The s o i l reaction i s weakly acidic in a l l horizons except the C 188 horizon which has a pH of 7.5. This suggests that the leaching of humic acids from the L-H horizon i s strongly affecting the development of the. s o i l . Exchangeable cations are present i n low amounts and the cation exchange capacity, although high in the L-H horizon decreases sharply with depth. Similarly, total nitrogen and total phosphorus occur i n low concentrations. Trophically, this s o i l i s considered to be submesotrophic to mesotrophic. The association consists of four vegetation layers. The tree layer i s dominated by Picea glauca which reaches i t s best growth in the A^ layer with a significance of 7. The only other tree species present i s Pinus contorta which occurs with low significance. The shrub layer i s dominated by Picea glauca and Shepherdia canadensis. Pseudotsuga menziesii i s present i n this plot as a single transgressive. The C layer i s dominated by Cornus canadensis and Linnaea borealis with species significances of 7.0 and 5.0 respectively. These species also occur i n the Rhytidiadelpho - Pleurozio - Pseudotsugetum *glaucae but with lower significance. Other important species in common between the two associations include: Calamagrostis rubescens, Pyrola virens, Oryzopsis  asperifolia. Arnica cordifolia and Pyrola secunda. Vaccinium myrtilloides and Vaccinium caespitosum >with species significances of 5 and 4 respectively, are dominant, characteristic species because of their exclusiveness for this association. The presence of V. caespitosum i s indicative of the long snow duration. The remaining characteristic species are: Geocaulon lividum, Habenaria orbiculata, Lycopodium annotinum, Lycopodium  complanatum and Viburnum edule. The D layer i s dominated by Pleurozium schreberi with a significance of 8. Constant associates include: Hylocomium splendens, and Ptilium c r i s t a - castrensis. Rhytidiadelphus triquetrus occurs here with a species significance of only 2 because of the more acidic surface s o i l . The only lichen species 189 present in this association i s Peltigera aphthosa with a significance of 3. The Pleurozio - Vaccinio - Piceetum glaucae i s dominated by Canadian boreal elements and i s present i n the Cariboo Zone only i n localized habitats with cool microclimates and fine textured soils with a high moisture retention capacity. Poo (interioris) - Calamagrostido (rubescentis) - Populion tremuloidis Poo (interioris) - Calamagrostido (rubescentis) - Populetum tremuloidis (ref. Tables; 71, 72, 73, 74, 83, and Fig. 24, 25) Order Characteristic Species Picea glauca Agoseris glauca Aster c i l i o l a t u s Delphinium brownii Epilobium angustifolium Pyrola secunda Silene menziesii Smillacina s t e l l a t a Thalictrum occidentale Drepanocladus uncinatus Alliance and Association Species Populus tremuloides Salix glauca Symphoricarpos occidentalis Astragalus alpinus Bromus anomalus Poa interior Potentilla g r a c i l i s Amblystegium serpens Important Companion Species Calamagrostis rubescens Lathyrus ochroleucus Rosa acicularis Vicia americana Agropyron subsecundum Pleurozium schreberi Brachythecium salebrosum The Poo - Calamagrostido - Populetum tremuloidis i s included in the order Piceetalia glaucae because of i t s similarity to associations dominated 190 Table 71 Plot Data Number of Plots Plot No. Plot Size (m2) Date analyzed Elevation (ft) Locality Physiography Landform Relief shape Exposure Slope gradient (°) Layer coverage (%) Aj layer A 2 layer A 3 layer Bj layer B 2 layer C layer D layer Plot coverage (%) Humus and l i t t e r Mineral s o i l Decaying wood So i l Hygrotope Trophotope Erosion Drainage Horizon depth (in) Poo ( i n t e r i o r i s ) - Calamagrostido (int e r i o r i s ) - calamagrostido - populetosum (rubescentis) - Populetum tremuloidis lonicero (involucratae) - caricetosum leptopodae 1 2 3 4 5 6 7 8 9 10 091 105 089 106 107 019 074 110 108 109 400 400 400 400 400 400 400 400 400 400 8/8 16/8 7/8 16/8 18/8 11/7 5/7 20/8 19/8 21/8 1968 1968 1968 1968 1966 1967 1968 1968 1968 1968 3300 3500 3600 3700 3700 2200 3000 3650 3700 3750 FP FP FP FP FP WL FP FP FP FP 51°43' 51°46' 51043' S l M l ' 51°41' 52-16' 51048' 51°41' 51°42' 51-43' 122°46' 123°02' 123°01' 123°03' 122°15' 122°39' 123°03' 1 123°03' 123°03' edge of gully edge of lake bench bottom gully concave f l a t f l a t concave concave straight .neutral. SW SE NE 0 0 0 11 4 8 0 0 0 0 _ _ 10 _ _ 62 . 21 26 23 53 SI 42 60 52 5 21 40 40 42 8 14 12 11 12 - 47 8 4 6 - 5 4 1 1 4 9 5 3 1 20 8 28 3 5 32 73 81 75 76 84 72 94 71 88 91 61 64 66 68 12 6 6 7 6 6 3 4 5 8 100 98 98 99 98 96 98 99 98 99 - 2 2 - - - - - - -- - - 1 2 4 2 1 2 1 subhygric - hygric •mesotrophic to permesotrophic. n i l moderate to well .hygric - subhydric. ...permesotrophic... n i l imperfect L-H 2-0 2-0 2-0 2-0 2-0 L-H 3-0 2-0 2-0 2-0 2-0 A - 0-5 - 0-6 0-4 Bl 0-15 0-4 0-5 0-6 0-5 B 0-6 5-13 0-7 6-12 4-13 B 2 - 4-16 5-15 - 5-13 C 6-24+ 13-28+ 7-26+ 12-23+ 13-24+ C 15-26+ 16-30+ 15-30+ 6-24+ 13-24+ Parent material g l a c i a l . . . g l a c i a l d r i f t . . . d r i f t ? . . g l a c i a l d r i f t . g l a c i a l d r i f t alluvium T a b i . 7 2 Poo ( i n t e r i o r i s ) - Calamagroatido (rubescentis) - Populetum tremuloidis :al*magroetlda - populetoaun treaajloldla (i nvolucrati ricetoaum leptopodae Number of Plots Plot Six* (n> 1 Elevation (ft) 1 Populua tremuloides 091 105 089 106 107 400 400 400 400 400 3300 3500 3600 3700 3700 019 074 110 108 109 400 400 400 400 400 2200 3000 3650 3700 3750 Avg Speclea Significance Asaociatlon Avg Species Significance 2 Pinus contorta 3 R"»* a c i c u l a r i a 4 Symphoricarpos o c c i d e n t a l i s Populus tremuloides 5 S a l i x glauca 6 A w l M c h l a r a l n l f o l l a 7 Lonicer* lnvolucrata 8 ftubua ldaeus 9 Shapherdl* canadensis 10 S a l i x bebblon* 11 Rlbes locustre Pinus contorta 12 Picea glauca C Layer 13 Calamagrostis rubescens 14 Lathyrua ochroleucus 15 Poa i n t e r i o r 16 Thalictrum occidentale 17 Aster c i l i o l a t u s 16 Bromus anomalus Rosa a c i c u l a r i s 19 V i c i a americana 20 A c h i l l e a m i llefolium 21 Fragaria v i r g i n i a n a 22 Galium boreal* 23 Smlleclna s t e l l a t a 24 Agropyron subsecundum 25 Taraxacum o f f i c i n a l e 26 Arctostaphylofl uva-ursi 27 Astragalus alpinus 28 Axenaria l a t e r i f l o r a 29 Erigeron specioaus 30 P o t e n t i l l a g r a c i l i s 31 V i o l a canadensis 32 Epilobium angustifolium 32 Gaum t r i f l o r u m 34 V i o l a adunca 35 Agoserls glauca 36 Carex coneinna 37 Petasites v l t i f o l i u a 38 Carex leptopoda 39 Allium cernuum 40 Heracleum 1anaturn 41 Clnna l a t i f o l i a Symphoricarpos o c c i d e n t a l i s 42 Astragalus miser Rubus ldaeus 43 Actaea rubra 44 Anemone mu l t i f i d a 45 Aster campestris 46 Qsmorhixa chi l e n a i s 47 Antennaria rosea 48 Delphinium brownii Picea glauca 49 Poa j u n c i f o l i a 50 Calamagrostis neglecta 51 Pyrola aecunda S3 P o t e n t i l l a pennsylvanlca Rlbea lacuatra 53 Stipa. columbiana 54 Cqulsetum arvenae 55 Phleum pretense 56 Sllene mensieaii 57 Stipa r i c h a r d s o n i i 56 T r l f o l i u j u repens 59 Cirsium follosum 60 Slymus glaucus 61 Agropyron spicatum 62 Geranium viscosissimum 63 Bromus inermls 64 C a s t l l l e j a ailniata 65 Hleracium umbellatum 66 Lithospermum ruderala 67 Poa pratenaia 68 V i o l a o r b i c u l a t a 69 Calamagrostis canadensis 70 Senecio lndecorus 71 Senecio pauperculus 9. I**yer (Bryophytes) 72 Amblyategium serpens 73 Pleurozium schreberi 74 Brachytheclum salebrosum 75 Ceratodon purpureu* 76 Drepanocladua uncinatus 77 Eurhynchlum pulchellum 78 Tortula r u r a l i s 79 Aulacomnium palustre B0 P t l l i u m c r i s t a - c a a t r e n s i s (Lichens) Bl P e l t i g e r a canina var. rufeac B2 P e l t i g e r a malacea B3 Pel t i g e r a aphthosa 84 P e l t i g e r a canina var. canina 4.2 2.2 4.+ 3.* 7.3 3.2 4.2 3.2 7.5 2.1 3.2 3.+ 4.2 2.1 1.1 2.1 3.1 3.2 2.1 2.1 2.1 3.2 3.1 1.* 2.* 1.* 3.2 6.4 6.4 3.2 3.2 3.2 2.1 2.1 2.2 2.2 2.2 2.1 3.2 3.2 3.2 2.2 3.1 3.2 2.1 2.1 2.1 2.1 3.2 2.2 3.2 3.2 2.2 2.1 1.8 1.5 3.2 2.2 2.0 2.6 2.2 2.2 i.e 2.0 l.B 4.6 2.4 0.8 0.8 0.2 0.4 0.6 0.2 0.2 O.S 0.4 0.4 0.6 3.2 2.6 2.2 0.4 0.2 2.0 1.4 0.8 1.0 0.4 0.6 5.3 7.3 7.6 8.6 7.6 3. * 2.* 2.* 4. * - 3.* 3.* 1.* 2.* 2.* - 2.1 -1.* 2.1 2.+ 2.2 1.1 3.2 1.4 3.3 3.2 - 3.2 2.2 3.3 2.1 3.1 2.1 2.1 2.* 3.2 2.2 2.2 4.2 7.4 2.1 4.3 2.1 3.1 5.3 4.3 5.2 4.2 5.2 3.1 3.1 1. + 2. * 5.2 2.1 2.+ 1.+ 2.1 1.1 2.2 1.-2.1 1.1 1.1 4.1 3.1 3.2 3.3 3.8 3.B 2.0 2.2 2.2 1.8 1.6 0.7 1.6 1.6 0.8 0.4 2.4 1.8 0.4 0.6 0.4 0.6 1.8 0.4 0.6 0.4 0.5 0.8 0.6 0.6 0.3 0.9 0.7 0.7 0.6 0.6 0.6 0.5 O.S 0.2 0.2 0.4 0.4 0.3 0.3 0.2 0.2 0.2 1.7 0.9 0.9 1.0 0.7 0.4 O.S 0.4 0.3 TOTAL SPECIES U n c i , sporadic*) Sporadic species 8 Layer SS Cornus s t o l o n i f e r a 86 Juniperus acopulorum 87 Rib*a oxyacanthoidee 69 Salix laaiandra C Layer 89 Agropyron trachycaulum 90 Antennaria anaphaloidai 91 Carex p r a e g r a c i l i a 92 Caraitium arvenae 93 Clematis columbiana 94 Cornus canadensis 95 Diaporum ttachycarpum 96 Peatuca saximontana 97 Linnaea borealia 074(2.1) 074(1 .•) 074(2.1) 074(1.1) 074(3.1) 106(2.1) 074(1.1) 107(1.1) 019(4.*) 019(2.2) 019(*.+) 106(1.1) 019(2.2) 98 Hahonia aquifolium 99 Oryzopai* a s p a r i f o l l a 100 Poa g r a c i l l i m a 101 Solidago multlradiata 102 Zygadenua gramlneus 103 Barbula convoluta 104 Dicranum polysetum 105 Hylocomium splendens 106 Leptobryum pyriforme 107 peltigera polydactyla 106 Pohlia nutans 109 P y l a i a i a polyantha 110 Tismia auatriaca 019(3.1) 019(3.2) 106(1.1) 107(2.1) 074(*.+> 106(1.*) 019(2.1) 091(3.2) 107(1 .•) 108(1.+) 109(1.+) 074(1.*) 109(2.1) Epiphytes Brachythecium aalebrosum Amblyatagium serpens 111 Xanthoria f a l l a x 112 Buell l a punctata 113 Rypogymnia phyaodee 114 Parmelia exaaperatula U S Peltigera praetaxtata 116 Physcia adscandena 192 by Picea glauca with regard to habitat and species of the C layer. It i s considered possible that this association may advance successionally to an association dominated by Picea glauca. The Poo - Calamagrostido - Populetum tremuloidis i s an association of restricted distribution in the Cariboo Zone and reaches i t s best development at elevations of greater than 3000 feet. It develops on subhygric to hygric habitats formed i n g u l l i e s , on level benches or at the edge of lakes, and on hygric to subhydric habitats formed in valleys on recently exposed stream terraces. It i s most common on level sites but also occurs on gentle slopes with either southerly or northerly exposures. There i s no evidence of surface erosion and s o i l drainage i s considered to vary from imperfect to moderate. The s o i l surface i s covered by a very extensive layer of l i t t e r composed mostly of Populus leaves. The s o i l s are developed from a parent material of either g l a c i a l d r i f t or alluvium. Four vegetation strata are present i n this association. The tree layer i s represented by three sublayers of which the A2 i s best developed. Populus tremuloides i s the dominant tree species with species significance ranging from 7 to 8. The shrub layer has two sublayers and ranges from poorly developed to very well developed. The most important shrubs are Rosa acicularis and Symphoricarpos occidentalis. The herb layer (C) is well developed with percentage cover ranging from 61% to 94%. Calamagrostis rubescens i s the dominant C layer species with an average species significance of 5.3. Lathyrus ochroleucus and Poa interior are constant subdominants with average species significances of 3.5 and 3.3 respectively. Other constant species characteristic of these moist habitats include: Thalictrum occidentale, Aster c i l i o l a t u s , Bromus anomalus, Smilacina s t e l l a t a and Agropyron subsecundum. Astragalus alpinus and Potentilla g r a c i l i s , Poo (interioris) Table 73 Soil Texture - Calamagrostido (rubescentis) - Populetum tremuloidis Number of Plots Plot No. poo - calamagrostido -populetosum tremuloidis 1 091 2 105 3 089 4 5 106 107 lonicero (involucratae) -caricetosum leptopodae 6, 7 8 9 10 019 074 110 108 109 A Horizon Bj Horizon Textural class . L L SL SiL SiCl LS SL S Clay (%) Mo 18 No 16 9 13 33 4 8 3 S i l t (%) 7\ 34 7\ 41 36 52 50 18 17 2 Sand (%) A 48 A 43 55 35 17 78 75 96 Coarse fragments • • g» g. g- g.c.s. None None None None Horizon B2 Horizon Textural class LS L SL CL SiL • SiC LS • LS Clay (%) 3 23 6 31 19 No 47 2 No 5 S i l t (%) 22 25 26 34 51 T") 45 16 14 Sand (%) 75 52 68 35 30 B 2 8 82 B 2 81 Coarse fragments g.c. g- C.S. None g.c. g.c. • None None • None Horizon C Horizon Textural class LS L SL L SL SCL SiL S S S Clay (%) 4 21 3 14 13 30 48 0 2 ' 1 S i l t (%) 15 31 38 39 31 2 44 0 2 3 Sand (%) 81 48 59 47 56 68 8 100 96 96 Coarse fragments g.c.s. g. C.S. g.c. g.c. g.c.s. g.c.s. g- g.c. g.c.s. g.c.s CO 194 Table 74 S o i l Chemical Analysis Poo ( i n t e r i o r i s ) - Calamagrostido (rubescentis) - Populetum tremuloidis poo ( i n t e r i o r i s ) - calamagrostido populetosum tremuloidis lonicero (involucratae) caricetosum leptopodae Number of Plots 1 3 4 5 6 7 8 9 10 Plot No. 091 105 089 106 107 019 074 110 108 109 L-H Horizon L-H Horizon C% 30.6 34 9 44 .0 41 .3 48 4 36.8 41 9 41 6 35. 8 32.9 N% 1.10 1 39 1 .21 1 .49 1 83 .87 1 74 1 03 1. 36 1.26 C/N 27.8 25 1 36 .4 27 .7 26 4 42.3 24 1 40 4 26. 3 26.1 P ppm 9.0 11 0 15 .0 12 .0 10 0 22.0 18 0 15 0 16. 0 8.0 Na .34 38 .40 .32 38 1.23 27 36 32 .28 K 1.76 2 98 3 .26 2 .5 2 88 3.18 1 64 3 52 2.64 3.46 Ca 51.6 34 8 33 .4 36.0 43 2 35.5 25 2 36 8 44. 8 41.6 Mg 15.6 24 8 16 .8 20 .8 23 8 17.0 29 4 13 4 13. 4 13.0 CEC 38.7 61 8 73 .5 81 .5 53 8 84.9 152 0 66 4 39. 8 42.3 PH 6.4 6 3 6 .5 6 .6 6 8 5.9 6 8 6 6 6. 7 6.5 A Horizon Bi Horizon C% 7 0 8 .1 7 0 0 3 1 5 7 0 3.9 N% 48 .28 41 .04 16 20 10 .20 C/N 14 6 28 .9 17 1 0 19 4 28 5 0 19.5 P ppm 16 0 8 .0 13 0 3.0 13 0 6 0 4. 0 6.0 Na No 22 No .12 11 .96 57 14 23 .12 K A 1 18 A 1 .38 1 41 .62 86 1 71 41 .41 Ca 5 9 5 .9 4 9 3.0 7 0 14 4 8. 1 6.7 Mg 8 3 6 .7 4 1 2.0 14 3 9 8 6. 7 3.5 CEC 24 5 31 .8 46 4 19.3 27 5 16 5 3. 9 8.9 pH 6 8 6 .3 6 9 6.3 7 6 6 4 6.6 6.3 B Horizon B 2 Horizon C* 8.3 2 2 .9 3 .4 2 5 0 1 6 0 N% .39 09 .07 .16 19 07 13 .05 C/N 21.3 24 4 12 .9 21 .3 13 2 0 12 3 0 P ppm 10.0 3 0 3 .0 3 .0 7 0 8 0 10 0 0 Na .43 61 .28 .55 54 No 53 21 No .33 K .52 1 52 .96 .86 95 B, 62 12 I .25 Ca 13.0 11 2 10 .9 9 .9 9 3 9 5 9 5 4.6 Mg 3.4 10 8 6 .4 17 .6 6 6 14 6 4 3 3.1 CEC 53.1 16 1 11 .4 7 .4 12 0 19 3 32 4 0 pH 6.5 7 8 6 .3 8 .2 7 5 8 2 6 6 7.0 C Horizon C Horizon c% 1.6 0 0 0 0 0 0 0 0 0 N% .12 06 .12 .13 07 .05 10 07 16 .06 C/N 13.3 0 0 0 0 0 0 0 0 0 P ppm 6.0 3 0 4 .0 6 .0 3 0 5.0 7 0 0 0 0 Na .57 1 14 .34 .68 59 .81 57 16 14 .17 K .74 1 01 1 .14 .61 1 72 .34 38 28 21 .65 Ca 11.7 11 2 13 .0 9 .5 12 1 4.S 10 9 4 2 5. 5 4.2 Mg 5.9 16 8 9 .0 12 .4 16 5 6.0 11 4 2 3 19. 3 1.9 CEC 16.8 11 8 7 .6 17 .4 4 1 12.1 16 1 0 0 0 pH 7.6 8 4 7 .8 8 .5 8 1 7.7 8 2 7 7 7. 8 7.6 195 both non-constants, are considered as characteristic species of this association. The D layer i s very poorly developed because of the heavy l i t t e r layer and has a percentage cover ranging from 3% to 12%. The most important bryophytes are: Amblystegium serpens, Pleurozium schreberi, Brachythecium  salebrosum, and Ceratodon purpureus. The only lichens present are Peltigera spp. and with low significances. The lack of lichens i s indicative of the hygric surface conditions. The epiphytic flora i s also poorly developed with Brachythecium  salebrosum and Amblystegium serpens occurring as the dominant species. The association appears to have a history of slight burning and may actually be promoted by f i r e as Populus tremuloides advances quickly by root suckers into li g h t l y burned areas (Rowe 1953, Moss 1955). The Poo -Calamagrostido - Populetum tremuloidis i s grazed only slightly as Calamagrostis  rubescens appears to have low p a l a t i b i l i t y for cattle. Two subassociations of the association are described, namely, the poo - calamagrostido - populetosum tremuloidis and the lonicero - caricetosum leptopodae. These have different hygrotopes and correspondingly different species compositions. Poo - Calamagrostido - Populetum tremuloidis 1. poo - calamagrostido - populetosum tremuloidis (ref. Fig. 24) Differential Species Shepherdia canadensis Arctostaphylos uva-ursi Astragalus miser Carex concinna Anemone multifida Aster campestris Antennaria rosea Geum triflorum Potentilla pennsylvanica 196 Differential Species (Cont'd) Stipa richardsonii This subassociation i s formed on lake edges, benches or gully bottoms with r e l i e f shapes ranging from f l a t to concave. The soi l s are considered to be moderately drained to well drained and only occasionally i s there evidence of gleying in the lower parts of the C horizon. This is the drier of the two subassociations and i s rated as subhygric to hygric. The soils are developed on a parent material of g l a c i a l d r i f t and are classed as either Orthic Dark Grey Chernozems (plots 105, 106 & 107) with a L-H,A,B,C, horizon sequence or Orthic Brown Wooded Soils (plots 091, & 089) with a L-H,B,C, horizon sequence. The Dark Grey Chernozemic s o i l s are closely related to Dark Grey Wooded Soils but have insufficient degradation of the surface horizon to be placed in the Podzolic Order. In the N.S.S.C. (1968) report they would most l i k e l y be placed as Luvisols. The soils are medium to coarse textured and there i s no significant textural change with depth. Coarse fragments were present in a l l horizons of the sampled soils with the exception of plot 089 which had coarse fragments only in the C horizon. Thus the parent material of plot 089 i s considered to be alluvium overlying g l a c i a l d r i f t . The L-H horizon has a weakly acidic reaction with pH values ranging from 6.3 to 6.8. The s o i l reaction of the mineral s o i l i s weakly acidic to circumneutral at the surface with pH values of 6.3 to 6.9 and becomes alkaline with depth. The pH values of the C horizon vary from 7.6 to 8.4. Exchangeable calcium and magnesium reach their highest concentrations in the L-H horizon where calcium values range from 33.4 meq/100 g to 51.6 meq/100 g, and magnesium values from 15.6 meq/100 g to 24.8 meq/100 g. This i s because the l i t t e r of Populus contains very high amounts of these cations (Daubenmire 1953). Both cations are present in lower amounts in the mineral s o i l and tend 197 to increase in concentration down the p r o f i l e . The higher concentrations of calcium and magnesium with increasing depth may in part account for the increased alkalinity with depth. In three of the sampled C horizons magnesium was present in higher amounts than was calcium which suggests that the s o i l developed from a magnesium rich parent rock. Exchangeable sodium i s present in low amounts in a l l horizons. Exchangeable potassium occurs in high amounts in the L-H horizon and decreases in concentration down the profile as does total phosphorus and percentage carbon. Carbon was not measureable in the C horizon with the exception of plot 091 where a trace amount was present. Nitrogen i s present in high amounts in the L-H horizon but the carbon:nitrogen ratios are also moderately high suggesting that decomposition may be retarded. Nitrogen concentrations are lower in the mineral s o i l and decrease with depth. However, the carbon:nitrogen ratios are also lower indicating that nitrogen i s available to higher plants. The cation exchange capacity i s high in the L-H horizon and decreases down the profile corresponding to the decrease in organic matter content. However, because of the generally loamy texture of the s o i l i t remains high even in the C horizon. These soils are considered to be mesotrophic to permesotrophic. Populus tremuloides i s the only tree species present in this sub-association and reaches i t s maximum importance in the A^ layer where i t has an average species significance of 7.2. Only in plot 089 are Populus trees t a l l enough to form an A( layer which i s poorly developed with a percentage cover of ten percent. The B, layer i s very poorly developed with a percentage cover varying from 0 up to 5%. It i s composed entirely of transgressives of Populus tremuloides and Pinus contorta. 198 The Bjlayer i s moderately well developed and i s dominated by Rosa  acicularis with an average species significance of 3.4. Salix glauca, a boreal subarctic species, i s present with an average species significance of 1.8 and i s most abundant in this subassociation as is Shepherdia canadensis which occurs with an average species significance of 1.6. The C layer of the Poo - Calamagrostido - Populetum tremuloidis i s best developed in this drier subassociation with percentage cover ranging from 71% to 94%. Calamagrostis rubescens dominates the C layer with an average species significance of 7.2. Arctostaphylos uva-ursi, a species characteristic of dry forest habitats, i s a constant subdominant with an average species significance of 4.8. Other species considered as d i f f e r e n t i a l for this subassociation include; Agoseris glauca, Astragalus miser, Carex  concinna, Geum triflorum, Anemone multifida, Aster campestris, Antennaria rosea, Potentilla pennsylvanica and Stipa richardsonii. A l l of these species are i n -dicative of drier sites. Cirsium foliosum, Agropyron spicatum, C a s t i l l e j a miniata, and Lithospermum ruderale are present in the Poo - Calamagrostido -Populetum tremuloidis only in this subassociation but with low species significances. ^ The D layer i s poorly developed with a percentage cover ranging from 6% to 12%. Pleurozium schreberi i s the dominant bryophyte with an average species significance of 3.2. Other important bryophytes include: Brachythecium  salebrosum, Ceratodon purpureus, Tortula r u r a l i s , and Amblystegium serpens. The lichen flora of the Poo - Calamagrostido - Populetum tremuloidis i s best developed in this subassociation. The dominant species are Peltigera  canina var. rufescens with an average species significance of 1.8 and Peltigera  malacea with an average species significance of 1.0. Of the two subassociations of the Poo - Calamagrostido - Populetum tremuloidis this one has the heaviest grazing history because of i t s upland position in close proximity to the open rangeland. 199 Fig. 24. The Poo - Calamagrostido - Populetum tremuloidis poo -calamagrostido - populetosum tremuloidis showing the characteristic dominance of Populus tremuloides and open understory. The herb layer (C) i s well developed in this association and i s dominated by Calamagrostis rubescens. Fig. 25. The Poo - Calamagrostido - Populetum tremuloidis lonicero caricetosum leptopodae showing the excellent development of Populus tremuloides and the characteristic densely developed shrub layer (B) which i s dominated largely by Rosa acicularis. 200 Poo - Calamagrostido - Populetum tremuloidis Z. lonicero (involucratae) - caricetosum leptopodae (ref. F i g . 25) Differential Species Amelanchier a l n i f o l i a Lonicera involucrata Rubus idaeus Salix bebbiana Ribes lacustre Petasites v i t i f o l i u s Carex ieptopoda Heracleum lanatum Cinna l a t i f o l i a Viola canadensis Arenaria laterflora Actaea rubra Osmorhiza chilensis Equisetum arvense This subassociation i s formed on stream terraces or in seepage gul l i e s . The surface r e l i e f shape was f l a t and the "exposure was neutral for a l l plots sampled except 019 which was located on an 8° slope with a northeast exposure. The so i l s are imperfectly drained and moderate to strong gleization i s evident in the C horizon. Because of i t s proximity to streams this sub-association i s considered to be flooded occasionally and thus the hygrotope i s rated as hygric to subhydric. The soi l s are formed on a parent material of alluvium with the exception of plot 019 where they appear to be formed on gl a c i a l d r i f t . They are classed as Orthic Brown Wooded soil s and have an L-H, B,C horizon sequence. The s o i l s are medium to coarse textured ranging from s i l t y clays to sands. Coarse fragments are present only in the C horizon with the exception of plot 019 where gravel sized particles were found right to the surface. The reaction of the L-H horizon i s weakly acidic with pH values ranging from 5.9 to 6.8. The reaction of the mineral s o i l i s weakly acidic to circumneutral at the surface and becomes alkaline with depth. Measured 201 pH values at the surface range from 6.3 to 7.6 whereas in the C horizon pH values range from 7.6 to 8.2. Exchangeable calcium i s present in high concentrations in the L-H horizon because of the large amounts of calcium in Populus l i t t e r (Daubenmire 1953). It occurs in lower concentrations in the mineral s o i l and tends to decrease with depth as does the organic matter content. Exchangeable magnesium is also present in high concentrations in the L-H horizon and decreases i n concentration in the mineral s o i l . Magnesium is present in greater concen-tration than calcium i n three plots suggesting that the parent material i s inherently rich in magnesium. Exchangeable sodium i s present i n low amounts in a l l horizons and thus i s not l i k e l y to interfere with the exchange complex. Potassium occurs with high concentrations in the L-H horizon and decreases down the p r o f i l e . Similarly, total phosphorus and percentage carbon decrease in concentration with depth; carbon i s not detectable in the C horizon. Nitrogen i s present in high amounts in the L-H horizon but the carbon:nitrogen ratios are also high suggesting that decomposition occurs slowly and that nitrogen may be limiting. Nitrogen i s present in lower concentrations in the mineral s o i l and decreases slightly with depth. However, the carbon:nitrogen ratios are more favourable indicating that nitrogen i s available to higher plants. The cation exchange capacity i s very high in the L-H horizon because of the high organic matter content. It i s substantially lower in the mineral s o i l and decreases down the profile as s o i l texture becomes coarser. The soils are considered to be inherently rich in nutrients and to also benefit from secondary enrichment of nutrients brought in during times of flooding. The habitat of this subassociation i s rated as being permesotrophic. The tree layer i s better developed i n this subassociation than in the poo - calamagrostido - populetosum tremuloidis and i s represented by three 202 sublayers. Populus tremuloides i s the dominant species with species significances ranging up to 8. The high shrub layer (B-^  ) i s poorly developed and i s composed largely of transgressives of Populus. The only other species represented i s Salix bebbiana which i s considered as d i f f e r e n t i a l for this subassociation. The B 2 layer i s very well developed in this moist habitat and has a percentage cover ranging up to 81%. The dominant shrub species are Rosa  acicularis and Symphoricarpos occidentalis with an average species significance of 6.8 and 5.2 respectively. Other species indicative of moist habitats and considered d i f f e r e n t i a l for the lonicero - caricetosum leptopodae include: Amelanchier a l n i f o l i a , Lonicera involucrata, Rubus idaeus and Ribes lacustre. The C layer i s not as well developed as i t s counterpart in the poo -calamagrostido - populetosum tremuloidis. Lathyrus ochroleucus i s the constant dominant species with an average species significance of 4.6. Thalictrum  occidentale and Aster c i l i o l a t u s are constant subdominants, both with average species significance of 3.8. Calamagrostis rubescens i s not as abundant in this wetter subassociation and occurs with an average species significance of only 3.4. Species indicative of moist habitats and considered d i f f e r e n t i a l for the subassociation include: Carex leptopoda, Osmorhiza chilensis, Petasites  v i t i f o l i u s , Cinna l a t i f o l i a , Heracleum lanatum, Viola canadensis, Arenaria  l a t e r i f l o r a , Actaea rubra and Equisetum arvense. Geranium viscosissimum, Bromus inermis, Viola orbiculata, Calamagrostis canadensis and Senecio indecorus occur in the Poo - Calamagrostido - Populetum tremuloidis only i n this sub-association. In the D layer of the lonicero -'caricetosum leptopodae, which is poorly developed, bryophytes are more important than lichens because of the hygric habitat. Amblystegium serpens i s the dominant species with an average species significance of 3.2 and Pleurozium schreberi i s a constant associate 203 but with a very low average significance of 1.4. Brachythecium salebrosum, Ceratodon purpureus, Eurhynchium pulchellum and Drepanocladus uncinatus are the only other bryophytes present. The lonicero - caricetosum leptopodae has a history of only very slight grazing, the effects of which do not appear to have altered the structure of the subassociation. Carico (concinnae) - Piceion glaucae Carico (concinnae) - Piceetum glaucae (ref. Tables; 75, 76, 77, 78, 83, and Fig. 26) Characteristic Combination of Species Order Characteristic Species Picea glauca Salix bebbiana Agoseris glauca Aster c i l i o l a t u s Epilobium angustifolium Petasites v i t i f o l i u s Pyrola secunda Silene menziesii Smilacina s t e l l a t a Thalictrum occidentale Drepanocladus uncinatus Alliance and Association Characteristic Species Antennaria anaphaloides Carex concinna Equisetum scirpoides Geocaulon lividum Schizachne purpurascens Senecio pauperculus Aulacomnium palustre Important Companion Species Rosa acicularis Shepherdia canadensis Betula glandulosa Salix monticola Salix brachycarpa Calamagrostis rubescens Arctostaphylos uva-ursi 204 Important Companion Species (Cont'd) Pleurozium schreberi Hylocomium splendens Ptilium crista-castrensis This association develops i n old g l a c i a l stream depressions or occasionally on old stream terraces and often borders the lakes in which the Carico - Salicetum monticolae i s found. The surface topography i s hummocky and the exposure i s considered to be t o t a l . The stream depressions i n which the association occurs appear to act as cold air drainage pathways from the surrounding uplands and thus a cool microclimate i s present. The s o i l surface i s covered by a small amount of decaying wood and by the extensive layer of l i t t e r composed largely of Picea needles. There is no evidence of surface erosion in this association and based on topographic position the s o i l drainage i s considered to vary from moderate to impeded. ^ The soi l s are formed on parent materials of alluvium and are classed either in the Chernozemic or Gleysolic Orders. Plots 068 and 111 have L-H, Ah, B, Cg horizon sequences and are classed as Gleyed Dark Grey Chernozems. These are closely related to Dark Grey Wooded soil s but have insufficient degradation of the surface horizon to be placed in the Podzolic Order. In the 1968, N.S.S.C. report they would probably be placed as Luvisols. Plot 099 has a L-H,Bg, Cg horizon sequence and i s classed as an Orthic Gleysol whereas plots 102 and 103 have L-H, Ah, Cg horizon sequences and are placed as Rego Humic Gleysols. A l l soi l s are strongly gleyed in the subsurface horizons and in plots 099 and 103 free water was present in the lower parts of the C horizon. Thus the s o i l s are considered to be poorly aerated and subjected to reducing conditions for at least part of the growing season. In the spring standing water may be present, temporarily, in the topographically lowest parts of the hummocky surface. There i s , however, no evidence that the association i s ever completely submerged. The hygrotope of the Carico - Piceetum glaucae i s therefore rated as being Table 75 Carico (concinnae) - Piceetum glaucae Plot Data Number of Plots 1 2 3 4 5 Plot No. 099 102 103 068 111 Plot Size (m2) 400 400 400 400 400 Date analyzed 9/8 13/8 14/8 26/6 22/8 1968 1968 1968 1968 1968 Elevation (ft) 3000 3150 3150 3250 3600 Locality FP • FP FP FP FP 51°45 51043. 51°43' 51°43' 51°42' 122°49 ' 122°39' 122°39' 122°40' 122°59' Physiography Landform stream terrace Relief shape hummocky Exposure ..neutral. Slope gradient (°) 0 0 0 0 0 Layer coverage (%) layer 8 22 21 - 42 A 2 layer 38 46 52 13 21 A3 layer 11 . 8 10 45 10 Bi layer 5 4 4 6 5 B 2 layer 26 21 10 14 8 C layer 16 46 42 48 45 D layer 41 58 56 57 38 Plot coverage (%) Humus and l i t t e r 97 96 99 92 98 Mineral s o i l - - - 2 -Decaying wood 3 4 1 6 2 Soil Hygrotope . (hydric) - hygric - (subhygric) Trophotope Erosion . .. n i l .. Drainage moderate moderate Horizon depth (in) L-H 7-0 3-0 2-0 1-0 2-0 A No A 0-13 0-12 0-9 0-4 B 0-14 No B No B 9-24 4-12 C 14-24+ 13-26+ 12-30+ 24-36+ 12-24+ Parent material alluvium T a L l e C a r i c o ( c o n c i n n a e ) - P i e c e t u n g l . i u c a c Number o l P l o t s P l o t No. P l o t Size (m2) E l e v a t i o n ( f t ) 099 10? I l l 068 111 400 400 400 400 400 3000 3150 1)50 3250 3600 3 P o p u l u s t r e n u l o i d c s 4 Rosa a c i c u l a r i s 5 B e t u l a g l a n d u l o s a 6 S h e p h o r d i a c a n a d e n s i s 7 S a l i x n o n t i c o l a 8 S y n p h o r i c a r p o s O c c i d e n t a 1 i 9 S a l i x b r a c h y c a r p a 10 S a l i x b e b b i a n a 11 S a l i x l a s i a n d r e 3.* 3.* 3.- 3. 3.2 2.1 3.1 3.1 3.1 5.2 1.* 3.1 2.* 2.1 3.* 2.1 3.. 12 Carex . 13 A n t e n n a r i a a n a p h a l o i d c s 14 A s t e r c i l i o l a t u s 15 C a l a m a g r o s t i s r u b e s c e n s Rosa a c i c u l a r i s 16 Taraxacum o f f i c i n a l e 17 A c h i l l e a m i l l e f o l i u m IS S e n e c i o p a u p o r c u l u s 19 G c o c a u l o n l i v i d u m 20 S m i l a c i n a s t e l l a t a 21 G a l i u m b o r c a l e 22 A r c t o s t a F h y l o s u v a - u r s i 23 E p i l o b i u n angust i f o l i ur. 24 A g o s e r i s g l a u c a 25 Poa j u n e i f o l i a 26 P y r o l a secunda 27 V i o l a acunca 2B S i l e n e r c n z i c i i i 29 E q u i s e t u r s c i r p o i d o s 30 L i n n a c a b o r c a l i s 31 S c h i z a c h n e n u r p u r a s c e n s 32 V i c i a a r r e r i c a n a 33 M i t f . l l a nuda 34 F r a g a r i a v i r g i n i a n a 35 Anemone n u l t i f i d a 36 T h a l i c t r u i r o c c i d e n t a l e 37 A n t e n n a r i a u n b r i n e l l a 38 Ranunculus a c c i t r a t u s 39 M u h l e n b e r g i a r i c h a r d s o n i s 40 A g r o p y r o n s p i c a t u m 41 A s t r a g a l u s a l p i n u s 42 C a r e x s a l t u c n s i s 43 P o t e n t i l l a a n s e r i n a 44 H a b e n a r i a o b t u s o t a 45 J u n c u s b a l t i c u s 46 P o t e n t i l l a d i v o r i i f o l i a S h e p h e r d i a c a n a d e n s i s 47 C a r e x p r a o g r a c i l t s 49 Pa m a s s i a p a l u s t r i s 49 E q u i s c t u m a r v e n s e 0 L a y e r ( B r y o p h y t e s ) 50 Aulacomniura p a l u s t r c 51 P l e u r o z i u m s c h r c b o r i 52 C e r a t o t l o n p u r p u r e u s 53 Hylocomium s p l c n d e n s 54 P t i l i u m c r i s t a - c a s t r e n s i s 55 Eurhynchium p u l c h e l l u m 56 Dicranum p o l y s c t u m 57 D r e p a n o c l a d u s u n c i n a t u s 58 Dicranum f u s c c s c c n s 59 R h y t i d i a t l c l p h u s t r i q u e c r u s 60 B r a c h y t h o c i u i r s a l e b r o s u m 61 T o r t u l a r u r a l i s 62 D i s t i c h i u m c a p i l l a c o u m 6 3 Hypnum r e v o l u t u n 64 Torcnthypnum n i t e n s 65 A n b l y s t e g i u m s e r p e n s 66 P o l y t r i c h u m j u n i p o r i n u r r 67 Dicranum s c o p a r i u n 68 T o r t e l l a t o r t u o s a ( L i c h e n s I 69 C l a d o n i a c h l o r o p h a c a 70 Pc11 i g e r a aph t h o s a 71 P e l t i g e r a c a n i n a v a i 72 C l a d o n i a g r a c i l i s 7 3 Pc 1 t i g e r a n a l a c c a 74 C l a d o n i a p o c i l l u n 75 C l a d o m a r i t i s 76 P e l t i g e r a c a n i n a var 77 C l a d o n i a c o r n u t a 7B L e c i d e a b c r c n g c r i a n a 79 C e t r a r i a o r i c c t o r u r 80 C l a d o n i a c e n o t c a 61 C l a d o n i a nemoxyna 3.2 5.3 5.3 5.2 4.2 1.1 2.2 3.2 2.1 4.2 3.* 1.1 1.* 1.* 2.* 2.- 2.* 1.* 1.* 3.1 3.1 3.2 2.2 3.2 2.2 1.' 1.1 1. 3.2 3.2 3.2 2.2 2.2 2.2 6.4 5.3 5.3 5.2 3.2 3.2 5.3 4.3 4.3 4.3 3.2 3.2 2.1 1.1 . 1 3.2 2.1 3.2 3.1 2.1 . r u f e s c e n s 3.2 2.1 2.1 3.2 2.1 2.1 3.2 0.6 0.6 0.6 0.4 TOTAL SPECIES ( i n c 1. s p o r a d i c s ) S p o r a d i c s p e c i e s 82 A m e l a n c h i e r a l n i f o l i a 0 66(2. 8 3 J u n i p e r u s coranums 10 3(1. B4 R i b e s l a c u s t r e 1021*. 95 Sa H x g l a u c a 111(1. C Laypr 86 A g r o p y r o n t r a c h y c a u 1 urn 099(2. 67 A r c n a r i a l a t e r i f l o r a 0 6BI1. B8 A s t e r c o n s p i c u u s 1L1I+. B9 A s t e r ] u n c i f o r m i s 103(1. 90 A s t e r p.insus 099 (1 . 91 Carex i l i s p c r m a 102(1. 12 l l r i q c r o n a c r i s 103(1. 93 L a t h y r u s o c h r o l e u c u s 111(1. 94 Moneses u n i f l u r j 09911. E p i p h y t e s 109 A i c c t o r i a q 1 afti a 110 ilypoqymn i J physodes 11 1 C c t r u r u p i n a s t r i 95 O x y t r o p i s campestr 96 P e t a s i t c s v i t i f o l i 97 P y r o l a a s a r i f o l i a 99 C l a d o n i a 100 C l a d o n i a 101 C l o u o n i a 102 C l a d o n i a 105 Psoror.a hypnorum 10 6 Rhyncostea 1e1 l a c o r p a 107 Tor to 11a f r a g i 1 i s lriB T o r t u l a r u r a l i f o r t r i s I 2'i Mypi-gyirn i 0681 1 .-10212.-099 I * . • 102 i ; . 0^8(1.-102 (1 .• 099 I 2 . • 10 3(1.-111(1.. 10 3(1.-099(1.-i Of.8 11 . 102 11.-009(1.-i' 1 i a c lo<j J n t u 1 .i o l ioi>sis h y p c r o p t a u i a itdscvndens 207 hygric, with the depressions between the hummocks being hydric in the spring and the hummocks drying to a subhygric condition during the summer. The soils are medium to coarse textured and tend to become coarser with depth because of an increase in sand content. They are classed, texturally, as s i l t y clay loams, s i l t y loams, sandy loams or sands. Coarse fragments are absent except in the subsurface horizons of 068 and 111 which contained a few gravels and cobbles. The L-H horizon ranges from circumneutral to alkaline with pH values varying from 6.4 to 8.1. The s o i l reaction of the mineral s o i l i s alkaline with pH values ranging from 7.8 up to 8.1 and there i s no significant change in alkalinity with depth. The highest cation concentrations occur in the L-H horizon with calcium dominating the exchange complex. Exchangeable sodium i s present in very high amounts in the l i t t e r with values up to 8.4 meg/100 g but decreases substantially through the mineral s o i l so i s not li k e l y to inhibit plant growth. Exchangeable potassium and total phosphorus are present i n high amounts i n the L-H horizon and decrease with depth corresponding to a decrease i n organic matter content. Exchangeable calcium and magnesium are present i n high amounts in the mineral s o i l and do not significantly change i n concentration with depth. Carbon percentages are high in the L-H and A horizons indicating a large accumulation of organic matter. However, in the subsurface horizons carbon i s not measureable, thus i t appears that the s o i l i s not enriched by organic matter movement down the profil e from the surface. Nitrogen i s present in high amounts in the L-H horizon and decreases in concentration with depth through the mineral s o i l corresponding to the decrease in organic matter content. Similarly, the cation exchange capacity i s very high in the L-H horizon with values ranging up to 138 meg/100 g and decreases with depth in the mineral s o i l to values around 20 meg/100 g. Table 77 Soil Texture Carico (concinnae) - Piceetum glaucae Number of Plots 1 2 3 Plot No. 099 102 103 A Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments B Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments C Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments No A SiL 25 49 26 None SiCL 15 55 30 None Data not avail-able None No B SiL 17 57 26 None S i i 7 49 44 None No B SL 11 30 59 None 068 111 SL SL 2 12 29 20 69 68 None None SiL SL 12 16 49 23 39 61 None g. S SL 0 13 1 12 99 75 209 Table 78 Soil Chemical Analysis Carico (concinnae) - Piceetum glaucae Number of Plots Plot No. 1 099 2 102 3 103 4 068 5 111 L-H Horizon C% N% C/N P ppm Na K Ca Mg CEC PH A Horizon C% N% C/N P ppm Na K Ca Mg' CEC pH B Horizon C% N% C/N P ppm Na K Ca Mg CEC pH C Horizon C% N% C/N P ppm Na K Ca Mg CEC pH 37.6 1.47 25.8 18.0 2.54 .78 34.2 37.0 103.7 7.7 No A 0 5. 17 13, 8, 7, .06 0 41 36 2 7 3 8 0 .12 0 6.0 .50 .73 18.5 15.6 26.2 8.0 46.8 1.72 27.2 27.0 8. 1. 27. 9, 138. 8. 4 82 4 6 0 1 Data not avail-able No B 0 .10 0 5.0 .69 .54 13.9 14.5 20.2 8.1 45.3 1.18 38.4 18.0 2.66 2.52 42.2 38.4 61.4 7.1 11.5 .53 21.7 16.0 1.38 1.21 9.3 20.0 73.1 8.1 No B 0 5. 13 14 20 8 .10 .0 .69 ,54 .9 ,5 .2 .1 36.5 1.25 29.2 19.0 2.58 .94 22.4 32.8 85.3 6.5 7.4 .31 23.9 10.0 1.11 .71 16.5 16.4 24.5 8.2 .11 0 7.0 .47 .40 15.9 9 17 7 0 .10 0 0 .33 .20 6.4 4.4 9 8.0 42.6 1.10 38.7 13.0 .66 2.70 49.6 15.0 62.3 6.4 25. 10. .2 .28 .7 ,0 .23 .51 14.6 7.7 31.1 7.8 35. 9. .4 .04 .0 .0 .29 .67 14.8 10.1 17.1 8.2 0 .06 0 8.0 .21 .51 11.2 7.8 11.8 8.1 210 There appears to be very l i t t l e movement of s o i l colloids down the profile by leaching in these poorly drained s o i l s . The uniform s o i l reaction and nutrient distribution i s thought to be controlled by the fluctuating water table which w i l l cause an upward movement of colloids through capillary r i s e . These soil s are nutritionally rich and the Carico - Piceetum glaucae i s con-sidered to be permesotrophic. Structurally the association consists of four vegetation layers. The well developed tree layer creates a heavily shaded habitat and i s composed of three sublayers of which the has the greatest percentage cover. The shrub layer (B) i s generally poorly developed and consists of two sublayers. The herb layer (C) is well developed as i s the bryophyte and lichen layer (D). Picea glauca, characteristic of these hygric sites, dominates the tree layer with species significances of up to 7. Pinus contorta and Populus t?:emuloides occur with low constancy and species significance in the drier communities of the association. Picea glauca also dominates the high shrub (B^) layer with an average species significance of 3.0. Salix monticola and Salix bebbiana are the only other species present in this layer with average species significances of 1.4 and 1.0 respectively. The B-, layer i s dominated by Rosa acicularis with an average species significance of 3.4. The presence of Betula glandulosa and Salix brachycarpa i s indicative of the cool microclimatic conditions of this association. Shepherdia canadensis i s the only other constant species and occurs on the drier hummocks. The C layer i s dominated by Carex concinna and Antennaria anaphaloides both of which are characteristic of this association. The constant presence of Calamagrostis rubescens suggests that the association i s seldom flooded as this species does not appear to be able to tolerate prolonged submergence. 211 Other constant species are Aster c i l i o l a t u s , Achillea millefolium and Senecio pauperculus. Arctostaphylos uva-ursi occurs with low species significance on hummocks which are drier than the rest of the habitat. Additional species occupying the drier parts of the association include: Geocaulon lividum, Galium boreale, Agoseris glauca, Vicia americana, Fragaria virginiana, Anemone multifida, Antennaria umbrinella and Agropyron spicatum. Equisetum scirpoides, Equisetum arvense, Ranunculus sceleratus, Parnassia palustris and Silene menziesii occur in depressions between the hummocks where the hygrotope varies from hygric to hydric. Species characteristic of moist forest sites include: Smilacina s t e l l a t a , Pyrola secunda, Linnaea borealis, Schizachne purpurascens, Mitella nuda and Thalictrum occidentale. Poa juncif o l i a, Juncus balticus, Potentilla anserina and Carex praegracilis a l l occur with low significance but are indicative of the alkaline, hygric conditions of the surface s o i l promoted by the fluctuating water table. Aulacomnium palustre with an average significance of 5.0 dominates the D layer and reaches i t s best development in the hygric to hydric depressions of the association. Pleurozium schreberi, Ceratodon purpureus, and Hylocomium  splendens are constant subdominants occurring mostly on hummocks and at the base of trees. Other constant bryophytes include : Ptilium crista»-castrensis ,  Eurhynchium pulchellum, Dicranum polysetum and Drepanocladus uncinatus. Lichens constitute less of the structure of the D layer than do bryophytes and reach maximum development in the drier parts of the association. The constant species are Cladonia chlorophaea, Petigera aphthosa, and Peltigera  canina var. rufescens, a l l of which are present with low significance. Additional lichens present with low significance but characteristic of dry sites include: Cladonia g r a c i l i s , C. pocillum, C. mitis and Cetraria ericetorum. The epiphytic flora i s well developed in this deeply shaded cool 212 Fig. 26. The Carico - Piceetum glaucae showing the hummocky development of the ground which is characteristic of the association and controls the distribution of species. Fig. 27. The Equiseto - Piceetum glaucae formed on an a l l u v i a l terrace and showing the excellent growth of Picea glauca. The C layer i s dominated by a dense stand of Equisetum  arvense which gives the association i t s characteristic appearance. 213 habitat. The most important epiphytes are: Alectoria glabra, Hypogymnia  physodes, Cetraria pinastri, Letharia vulpina, Parmelia sulcata, and Usnea  glabrescens. The Carico - Piceetum glaucae has a history of very slight grazing which does not appear to have substantially altered the structure of this association. Equiseto (arvensis) - Piceion glaucae Equiseto (arvensis) - Piceetum glaucae (ref. Tables; 79, 80, 81, 82, 83, and Fig. 27) Characteristic Combination of Species Order Characteristic Species Picea glauca Salix bebbiana Aster c i l i o l a t u s Delphinium brownii Epilobium angustifolium Petasites v i t i f o l i u s Pyrola secunda Silene menziesii Smilacina s t e l l a t a Thalictrum occidentale Drepanocladus uncinatus Alliance and Association Characteristic Species Alnus tenuifolia Cornus stolonifera Lonicera involucrata Ribes lacustre Viburnum edule Actaea rubra Cinna l a t i f o l i a Equisetum arvense Mitella nuda Moneses uniflora Pyrola a s a r i f o l i a Important Companion Species Rosa acicularis Linnaea borealis Eurhynchium pulchellum Pleurozium schreberi 214 Important Companion Species (Cont'd) Hylocomium splendens Ptilium crista-castrensis The Equiseto - Piceetum glaucae i s developed on newly formed a l l u v i a l terraces along streams and rivers on the Fraser Plateau. The terraces are either level with neutral exposures or gently sloping with northerly exposures. The r e l i e f shape varies from f l a t to concave. A cool microclimate prevails in this association as a result of cold a i r movement along the streams and rivers. The s o i l surface i s covered by a thick l i t t e r layer ranging in extent from 90% to 98% of the total surface area. In a l l plots sampled a small percentage of the surface was covered by decaying wood and mineral s o i l was exposed in only one plot. Soil drainage i s rated as moderate to imperfect and free water i s always present in the lower part of the s o i l p r o f i l e . Evidence of gleization in the form of mottling i s consistently present i n the subsurface s o i l s . This association i s frequently flooded. The Equiseto - Piceetum glaucae i s considered to be subhydric up to hydric during times of flooding. The soi l s are developed on a parent material of alluvium and c l a s s i f i e d as follows: Plots 090, 096, 100 and 101 have Gleyed Regosolic soi l s with an L-H, Cg, horizon sequence; plot 097 has a Rego Gleysolic s o i l with an L-H, Cg horizon sequence and plot 036 has an Orthic Humic Gleysolic s o i l with an L-H, Ah, Cg horizon sequence. The soi l s are medium to coarse textured and range from s i l t loams to sands. The soi l s tend to become coarser with depth as sand content increases down the p r o f i l e . Coarse fragments are generally absent but gravels and cobbles were found in the lower part of the C horizon of two plots. The coarse s o i l texture w i l l allow rapid drainage of the surface soi l s following flooding and thus maintain a well aerated s o i l . 215 Table 79 Equiseto (arvensis) - Piceetum glaucae Plot Data Number of Plots 1 2 3 4 5 6 Plot No. 097 096 036 100 101 090 Plot Size (m2) 400 400 400 400 400 400 Date analyzed 5/8 2/8 31/7 9/8 27/8 1/8 1968 1968 1967 1968 1968 1968 Elevation (ft) 2800 2850 3020 3500 3600 3650 Locality FP FP FP FP FP FP 51°48' 51°47' 51044. 51°43' 51044. 122°37' 122°37' 122°38 ' 122°58' 122°56' 122°57 Physiography Landform stream Relief shape concave concave f l a t Exposure NW NW neutral , Slope gradient (°) 9 14 0 0 0 0 Layer coverage (%) Aj layer 41 42 64 51 48 26 A 2 layer 9 24 12 18 18 42 A3 layer 3 12 6 5 4 22 Bi layer 15 11 4 6 8 1 B 2 layer 20 18 9 11 26 4 C layer 96 46 85 64 75 71 D layer 74 86 21 13 23 41 Plot coverage (%) Humus and l i t t e r 98 95 90 98 98 96 Mineral s o i l - 1 - - - -Decaying wood 2 4 10 2 2 4 Soil Hygrotope Trophotope Erosion Drainage hygric - (hydric) .. subeutrophic .. n i l moderate moder-to imperfect ate imperfect Horizon depth (in) L-H surface subsurface 0-13 13-27+ 3-0 0-10 10-22+ 6-0 0-11 11-20+ 2-0 0-10 10-26+ 2-0 0-10 10-26+ 1-0 0-10 10-30+ Parent material alluvium Table 80 E q u i s e t o (arvensis) - Piceetum glaucae Number of P l o t s P l o t No. P l o t S i z e <m2) E l e v a t i o n ( f t ) 097 096 096 100 101 090 400 400 400 400 400 400 2800 2850 3020 3500 3600 3650 A Layer 1 P i c e a g l a u c a Avg Species S i g n i f i c a n c e 2 Populus tremuloides 3 Pseudotsuga m e n z i e s i i 4 Populus t r i c h o c a r p a B Layer 5 L o n i c e r a i n v o l u c r a t a 6 Rosa a c i c u l a r i s 7 Ribes l a c u s t r e Piece glauca 8 Viburnum edule 9 Rubus idaeus 10 S a l i x bebbiana 11 Alnus t e r t u i f o l i a 12 Cornus s t o l o n i f e r a 3.2 4.2 3.2 1.1 4.2 4-3 5-3 4.2 2.1 3.2 3.2 3.2 2.1 3.3 2.2 2.1 3.2 3.2 I I I I I I I I I C Layer 15 Equisetum arvensc 16 Linnaca b o r e a l i s 17 A s t e r c i l i o l a t u s IB Mite 11a nuda 19 P e t a s i t e s v i t i f o l i u s 20 P y r o l a secunda 21 S m i l a c i n a s t e l l a t a 22 Cinna l a t i f o l i a 23 P y r o l a a s a r i f o l i a 24 S i l e n e m e n z i e s i i 25 Lathyrus ochroleucus 26 Moneaea u n i f l o r a 27 E p i l o b i u m a n g u s t i f o l i u m 28 Taraxacum o f f i c i n a l e 29 V i c i a americana 30 Actaca rubra 31 Galium b o r e a l e 32 T h a l i c t r u m o c c i d e n t a l e 33 Agropyron subsecundum 34 V i o l a canadensis 35 Heracleum laneturn Rosa a c i c u l a r i s 36 F r a g a r i a v i r g i n i a n a 37 P y r o l a v i r e n s 38 Poa i n t e r i o r 39 Bromus anomalus 40 Calamagrostis canadensis 41 Habenaria obtusata 42 Delphinium brownii P i c e a glauca 4 3 Rubus pubescens 44 A s t e r conspicuus 45 Carex concinna 46 Carex concinnoides 47 C i r c a e a a l p i n a 48 Equisetum s c i r p o i d e s 49 Galium t r i f l o r u m 50 Gcocaulon l i v i d u m 51 Luzula p a r v i f l o r a Ribes l a c u s t r e 52 U r t i c a d i o i c a D Layer (Bryophytes) 53 Eurhynchium p u l c h e l l u m 54 Hy1ocomiurn splendcns 55 Pleurozium s c h r e b e r i 56 Drepanocladus uncinatus 57 Timmia a u s t r i a c a 5B Brachythecium salebrosum 59 P t i l i u m c r i s t a - e a s t r e n s i s 60 Ceratodon purpureus 61 R h y t i d i a d e l p h u s t r i q u e t r u s 62 Dicranum fuscescens 6 3 Mni urn r u g i cum 64 Amblystegium serpens 65 Marchantia polymorpha (Lichens) 66 P e l t i g e r a aphthosa 67 P e l t i g e r a canina var. canina 68 P e l t i g e r a canina var. r u f e s c e n s 69 P e l t i g e r a h o r i z o n t a l i s 70 Nephroma hel v e t i c u m 5.2 5.1 1.1 3.2 2.2 1.1 2.1 1.1 - 1.1 1.* 1.+ 1.+ 1.* 2.1 1. + 1.* 3.2 1.* 2.* 1.4 1.1 1.+ - 3.1 1.' + 2. + 1.1 4.1 2. 1 1.1 4.2 1.1 2. 1 3.1 2.2 2.1 3.2 2.1 2.2 2.2 2.1 TOTAL SPECIES ( i n c l . s p o radics) 48 60 54 45 39 57 S p o r a d i c s p e c i e s 71 Ribes americanum 036 (3 • ) 90 Goodyera oblo n g i f o l i a 096 (1. + ) 72 S a l i x s i t c h e n s i s 100 ( + •) 91 Goodyera repens 097(1.*! 73 Shepherdia canadensis 096 (• • ) 92 Habenaria s a c c a t a 036(•.*) 93 Osmorhiza depauperata 036 (3. + ) — **ayer 94 Phleum pratense 090(*.*) 74 Agropyron spicatum 100 (2 *) 95 Poa p a l u s t r i s 036(1.*) 75 A l l i u m cernuum 096 (I 96 Rubus idaeus 100(1.1) 76 A r a l i a n u d i c a u l i s 097 (4 3) 97 Senecio indecorus 090 12.*) 77 A r e n a r i a l a t e r i f l o r a 09712 2) 98 Senecio paupcrculus 096 (•.•) 78 A r n i c a c o r d i f o l i a 090 (1 •) 79 A s t e r modestus 036 (• +) - a y e r 80 A s t r a g a l u s americanus 036 (2 + ) 99 C e t r a r i a e r i c e t o r u m 096 (1 .*) 81 Calamagrostis rubescens 096 (2 1) 100 C l a d o n i a m u l t i f o r m i s 096 ( 1 .*) 82 Carex pachystachya 090 ( 3 1) 101 CHmacium dendroides 090(6.4) S3 Carex s a l t u o n s i a 036 (• 102 Cratoneuron f i l i c i n u m 097 13.2) 84 C o r y d a l i s aurca 096 ( + *) 103 Dicranum polysetum 096 (3.2) 85 Disporum trachycarpum 096 11 +) 104 Funar i a hygrometr i ca 096(1.+) 86 Epilobium w a t s o n i i 036(1 •) 105 Leptobryum p y r i f o r m c 096 (•.•) 87 Galium t r i f i d u m 097(2 1) 106 Mnium s p i n u l o s i s 036(•.•) BB Geranium r i c h a r d s o n i i 036 (2 •) 107 Poh1i a cruda 096(*-») 89 C l y c e r i a s t r i a t a 090 (1 + ) 10B T h u i d i um recogni turn 036(1.1) Epiphy ta 109 L c t h a r i a v u l p i n a (IV) 116 A l c c t o r i a sarmcntoaa (II) 110 llypogymnia phyaodon (IV) 117 Hypogymni a aus terodes (II) 111 A l c c t o r i a g l a b r a ( I t i ) 1 IB Parmclia c x a s p c r a t u l a (II) 112 Parmclia s u l c a t a (1)1) ) 19 P a r m c l i o p s i s ambigua (II) ) 13 Rama 1i na tar i nacea (111) 120 Usnea h i r t a (II) 114 Uanea a l p i na (III) 121 A l c c t o r i a americana (I) l i b Usnea g l a b r c s c c n a (III) 122 Usnea comosa (I) 217 The reaction of the L-H horizon i s slightly acidic to alkaline with pH values ranging from 5.8 to 7.8. The low pH value of 5.8 was recorded in plot 096 and i s thought to be due to the high abundance of Pleurozium schreberi. The mineral s o i l has a neutral to alkaline reaction at the surface with pH values ranging from 7.1 to 8.2. Alkalinity increases with depth as organic matter content decreases and the lower parts of the C horizons have pH values ranging from 7.4 to 8.3; on five plots pH values greater than 8.0 were recorded. Exchangeable calcium and magnesium are present in very high amounts in the L-H horizon which suggests that Picea glauca l i t t e r i s rich in these cations. They occur i n high amounts in the mineral s o i l and tend to decrease in concentration down the pr o f i l e . The high concentration of magnesium in the C horizon suggests that the parent material i s magnesium rich. Exchangeable sodium i s present in low amounts in a l l horizons and i s thus not li k e l y to interfere with the exchange complex. Exchangeable potassium i s present in moderately high amounts in the L-H horizon, decreases in concentration down the prof i l e and i s present in only trace amounts in ^ he lower parts of the C horizon. Similarly, available phosphorus i s present in high amounts in the L-H horizon and decreases substantially with depth. Because of the high organic matter content, the cation exchange capacity i s very high in the L-H horizon with values up to 125 meg/100 g. The cation exchange capacity i s lower in the mineral s o i l and decreases down the profile corresponding to a decrease i n organic matter content and an increase in sand content. Nitrogen occurs i n moderate amounts in the L-H horizon but the carbon:nitrogen ratios here are high indicating that the organic matter does not contain sufficient nitrogen for decomposition and a competition for nitrogen between the microflora and higher plants i s li k e l y to result. Nitrogen i s present in low amounts in the mineral s o i l but because of the carbon:nitrogen ratios are generally more favourable Table 8 1 Soil Texture Equiseto (arvensis) - Piceetum glaucae Number of Plots 1 2 3 4 5 6 Plot No. • 097 096 036 100 101 090 Surface Horizon Textural class Clay (%) S i l t (%) Sand (%) Coarse fragments o r g a n i c L 19 45 36 SiL 21 53 26 None SiL 14 48 38 SL 9 18 73 S 1 8 91 Subsurface Horizon Textural class L L L S S S Clay (%) 25 28 * 23 3 3 0 S i l t (%) 33 32 43 6 1 0 Sand (%) 42 40 34 91 96 100 Coarse fragments None g.c. None None None g. JO r-1 CO 219 Table 82 Soil Chemical Analysis Equiseto (arvensis) - Piceetum glaucae Number of Plots 1 2 3 4 5 6 Plot No. 097 096 036 100 101 090 L-H Horizon C% - 52.4 47.8 14.7 23.1 14.6 N% - 1.16 1.46 .68 1.01 .53 C/N - 45.2 32.7 21.6 22.9 27.5 P ppm - 27.0 19.0 12.0 14.0 14.0 Na - .56 2.10 .30 .34 .36 K - .98 6.4 2.72 1.28 2.16 Ca - 34.4 55.0 27.0 16.8 29.8 Mg - 12.6 33.3 11.0 4.4 10.6 CEC - 118.3 126.4 41.1 41.0 41.8 pH - 5.8 7.8 6.4 6.3 6.5 Surface Horizon C% 34.9 0 6.3 4.7 0 0 N% 1.45 .04 .16 .43 .09 .10 C/N 24.1 0 45.6 10.9 0 0 P ppm 12.0 4.0 13.0 8.0 5.0 11.0 Na 1.38 .85 .82 .36 .27 .33 K 2.72 .57 .25 .55 .39 .16 Ca 43.6 14.1 45.5 8.1 10.5 10.1 Mg 32.8 10.2 11.2 12.0 2.4 4.6 CEC 28.4 16.3 32.0 18.5 8.0 34.7 pH 6.8 8.2 7.8 7.2 7.1 7.3 Subsurface Horizon C% 2.6 0 4.2 0 0 0 N% .17 .06 .10 .64 .06 .11 C/N 15.3 0 42.0 0 0 0 P ppm 8.0 5.0 6.0 0 0 0 Na .59 2.5 .36 .39 .34 .18 K .46 .57 .31 .30 .35 .12 Ca 14.6 9.7 32.0 3.1 9.5 3.9 Mg 14.6 12.7 6.3 3.3 14.3 2.4 CEC 18.2 12.5 16.3 0 0 0 pH 8.0 8.3 8.1 8.1 8.1 7.4 220 i t i s available to higher plants. The low nitrogen concentrations are probably a result of the youthfulness of the soil s and high water table as under these conditions very l i t t l e organic matter accumulation can occur. This i s supported by the fact that carbon i s either not measureable or present i n very low amounts in the subsurface s o i l s . The soil s of this association are considered to be continually enriched by nutrients brought in during times of flooding which may in part account for the higher nutritional status of the surface s o i l . The Equiseto - Piceetum glaucae i s considered to be subeutrophic. Structurally, the Equiseto - Piceetum glaucae i s composed of a well developed tree layer which provides a heavily shaded habitat, a moderately well developed shrub layer, a well developed herb layer and a moderately well developed bryophyte and lichen layer. The tree layer consists of three sublayers of which the A^ i s best developed with a percentage cover ranging from 26% to 64%. Picea glauca i s the dominant tree species with species significance of up to 8. Populus tremuloides and Populus trichocarpa are also present but with low constancy and significance. Pseudotsuga menziesii occurs only marginally in this association on parts of the terraces which are no longer flooded, as this species i s unable to tolerate submergence. In the sampled plots i t occurred only on the upper slope of plot 096. The shrub layer has two sublayers of which the B^ i s best developed with a percentage cover ranging from 4% to 26%. Lonicera involucrata and Rosa acicularis are constant dominants with average species significances of 3.3 and 3.2 respectively. Other shrub species characteristic of this cool moist habitat are: Salix bebbiana, Ribes lacustre, Viburnum edule, Rubus idaeus,  Alnus tenuifolia, and Cornus stolonifera. The C layer i s dominated by Equisetum arvense which occurs in nearly pure stands with an average species significance of 6.5. Linnaea borealis, 221 Aster colioalatus and Mitella nuda occur beneath the Equisetum arvense cover as constant subdominants. Other constant species characteristic of the association and indicative of cool hygric sites include: Petasites v i t i f o l i u s , Pyrola secunda, Smilacina st e l l a t a , Cinna l a t i f o l i a , Pyrola a s a r i f o l i a , Silene  menziesii and Moneses uniflora. Additional species although non-constant, typifying the subhydric conditions are: Actaea rubra, Thalictrum occidentale, Viola canadensis, Heracleum lanatum, Calamagrostis canadensis, Equisetum  scirpoides, Delphinium brownii and LTrtica dioica. Calamagrostis rubescens occurs only marginally in this association, on parts of the terraces which are rarely flooded. This suggests that this species cannot tolerate submergence. Species occurring as sporadics but considered as indicative of heavily shaded moist to wet habitats include: Ribes americanum, Aralia nudicaulis, Disporum  trachycarpum, Epilobium watsonii, Glyceria st r i a t a , Goodyera oblongifolia, Goodyera repens and Habenaria saccata. The D layer i s generally well developed with bryophytes being more important than lichens as lichen floras are poorly developed on hygric to hydric sites. Eurhynchium pulchellum i s the dominant bryophyte with an average species significance of 4.2. Hylocomium splendens and Pleurozium schreberi are constant subdominants with average species significances of 3.8 and 3.7 respectively. Pleurozium schreberi reaches a maximum significance of 7 in plot 096 which i s considered to be no longer flooded. Additional important bryophyte species include: Drepanocladus uncinatus, Timmia austriaca, Brachythecium salebrosum, Ptilium crista-castrensis and Rhytidiadelphus  triquetrus. Peltigera aphthosa with an average species significance of 2.0 is the only constant lichen species. Peltigera canina var. canina, P. canina var. rufescens, P. horizontalis and Nephroma helveticum are the only other lichen species which occurred in two or more plots. 222 The epiphytic fl o r a i s poorly developed with Letharia vulpina and Hypogymnia physodes being the most important species. A l l other epiphytic species occur with a constancy of class III or less. The Equiseto - Piceetum glaucae appears to have a history of damage caused largely by floods and wind with minor disturbance resulting from f i r e . Grazing i s considered to be negligible in this association. 223 Table 83. Summary Synthesis Table for the Ecosystem Units of the Cariboo Zone Species are l i s t e d by the order, the alliance or the association for which they are characteristic. The assoc-iations are given in an abbreviated form across the top of the table. Species distribution by association i s shown thus making a f l o r i s t i c comparison of associations possible. Each entry consists of the constancy class (I-V), the average Secies significance and the range of species significance .g. V 1.9(1-3)]. The boxed values indicate the ecosystem unit for which a particular group of species i s characteristic. Species which do not appear to have a f f i n i t y for any particular ecosystem unit are l i s t e d at the bottom of the table as companion species under the headings of: General Companion Species (those which are common in grassland and forest associations); Forest Companion Species (those most common in forest associations); and Forest Companion Species, Boreal Elements (those most common in forest associations but representative of the Boreal Forest). Only species which occurred with a constancy of 60% or greater in at least one association are l i s t e d in the table. • H.j. D . - S . g , M. - B . g . j . b . A. - P.*-?. C. - P . * g . p . * g . p . R. - P . * g . ' P . * . CARICETAXXA ROSTRATAE CARICION ROSTRATAE CARICETUM ROSTRATAE Calaj&agrostis n e g l e c t s Carex a q u a t i l i s Carex r o s t r a t a H i p p u r i s v u l g a r i s SALXCETALIA SALICION MONTICOLAE CARICO - SALICETUM MONTICOLAE S a l i x arbusculoides S a l i x monticola A s t e r j u n c i f o r m i s Calamagrostis canadensis Galium t r i f i d u m Mniust rugicum R h y n c h o s t e g i e l l a compacts, SCIRPETALIA VALIDI SCIRPION VALIDI SCIRPETUM VALIDI Cnenopodiam rubrum Ranuncuius a c e l e r a t u s Rwmex maritimus S c i r p u s v a l i d u s PUCCINELLIETALIA AIROIDIS DISTICHLIOR STRICTAE A s t e r pansus Carex p r a e g r a c i l i s D i s t i c h l i s s t r i c t * Hordeum jubatua P u c c i n e l l i a a i r o i d e s S p a r t i n a g r a c i l i s PUCCINELLIO - HORDEETUM JUBATI E l e o c h a r i s p a l u s t r i s Elymus glaucus Ranunculus cymbal*ria T r i g l o c h i n p a l u s t r i s DISTICHLO - SPARTINETUM GRACILIS Agropyron tra c h y c s u l i a t A t r i p l e x t r u n c a t a G r i n d * 1 l a aquarrosa Polygonum a r v i c u l a r s Suaeda depressa BE1TJLETALIA GLANDULOSAE MUHLENBERGIO - BETULION GLANDULOSAE MUHLENBERGIO - BETULETUM GXANDOLOSAS Bet u l a glandulosa S a l i x brachycarpa E r i g e r o n a c r i s Muhlenbergia r i c h a r d s o n i s S i s y r i n c h i u s t aarmentoeum Cladonia c a r i o s a KOELERIO - AGROPYRETALIA SPICATI Agropyron spicatum A r a b i s h o l b o e l l i i A r t e m i s i a f r i g i d a E r i g e r o n f l a g e l l a r i s K o e l e r i a g r a c i l i s Tragopogon dubiua T o r t u l a r u r a l i s C ladonia p o c i l l u m Cladonia p y x i d a t a STIPION COLUMBIANAE Antennaria rosea Antennaria u m b r i n e l l a Aster campestris A s t r a g a l u s d a s y g l o t t i s Carex p r a t i c o l a Cerastium arvense f e s t u c a saximontana Juncus b a l t i c u s Orthocarpus h i s p i d u s Poa j u n c i f o l i a Poa p r a t e n s i s P o t e n t i l l a p e n n s y l r a n i c a S t i p a Columbian* POO - ELYXETUM CINEREI Elymus cinereus ANTENNARIO - POETUM SECUNDAE Antennaria dimorpha Lepidium densiflorum Poa secunda JUNCETOSUM BALTICI Chenopodium l e p t o p h y l l u a