UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A phytosociological study of fir and spruce forests on the plateau of Cape Breton Island, Nova Scotia Smith, Richard T. 1974

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1975_A6_7 S65_8.pdf [ 11.67MB ]
Metadata
JSON: 831-1.0100007.json
JSON-LD: 831-1.0100007-ld.json
RDF/XML (Pretty): 831-1.0100007-rdf.xml
RDF/JSON: 831-1.0100007-rdf.json
Turtle: 831-1.0100007-turtle.txt
N-Triples: 831-1.0100007-rdf-ntriples.txt
Original Record: 831-1.0100007-source.json
Full Text
831-1.0100007-fulltext.txt
Citation
831-1.0100007.ris

Full Text

A PHYTOSOCIOLOGICAL STUDY OF F I R AND ON THE PLATEAU OF CAPE BRETON  SPRUCE FORESTS  ISLAND, NOVA  SCOTIA  I  by RICHARD B.Sc,  A THESIS OF  Acadia  T. SMITH University,  SUBMITTED I N P A R T I A L  1970  FULFILLMENT  THE REQUIREMENTS FOR THE DEGREE OF OF SCIENCE  MASTER  in  t h e Department of Botany  We  accept  required  THE  this  thesis  as conforming  to the  standard  U N I V E R S I T Y OF B R I T I S H November  1974  COLUMBIA  In p r e s e n t i n g t h i s  thesis  an advanced degree at  further  fulfilment  of  the  requirements  the U n i v e r s i t y of B r i t i s h Columbia, I agree  the L i b r a r y s h a l l make it I  in p a r t i a l  freely  available  for  this  thesis  f o r s c h o l a r l y purposes may be granted by the Head of my Department  of  this  thesis for  It  financial  of  gain s h a l l not  BOTANY  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8. Canada  Date  A p r i l 17, 1975  or  i s understood that copying or p u b l i c a t i o n  written permission.  Department  that  reference and study.  agree 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 copying o f  by h i s r e p r e s e n t a t i v e s .  for  be allowed without my  ABSTRACT  .  The present study was designed to: a) employ phytosociological methods to characterize the major spruce and f i r forests of the Cape Breton Plateau, b) measure specific climatic and edaphic factors and relate these to the forest vegetation and c) assess the boreal nature of the Plateau forests through comparisons with boreal forests i n neighbouring regions of eastern Canada. Climatic measurements were made from June to l a t e August during a two year period. These included continuous recordings of temperature and wind and weekly measurements of precipitation. Daily maximum and minimum temperatures and weekly precipitation were used for climatic characterization of the area and f o r comparison with D.O.T. meteorological data at Cheticamp and Ingonish Beach i n the lowlands of Cape Breton. Soils were sampled, where possible, i n each forest stand. Profiles were described and samples were taken for quantitative analysis of texture, nitrogen, phosphorus, carbon, pH, available water, and exchangeable calcium, potassium, magnesium and sodium. Vegetation study resulted i n the recognition of three forest associations.  The most widespread of these i s the Abies  balsamea  spinulosa  - Diyopteris  f i r association.  - Hylocomium  vmbratvm. or upland  This i s the most productive of the three associations.  I t forms the climatic climax of the area, and occurs on the betterdrained s o i l s of low ridges.  Stands of this type have r e l a t i v e l y  closed tree canopies i n which Abies balsamea  i s predominant and  ii Betula  papyvifera  occurs frequently but with low densities. Shrub  layers are poorly developed because of poor light conditions, and the herb and bryophyte layers are moderately to well developed. The Picea mariana  - Plevjrozivm  scnvebevi  or black spruce  association i s common, and develops both on poorly-drained organic s o i l s i n low lying areas, and on thin stony s o i l s on ridges. Tree growth i s very poor i n these areas.  Stands of this type lack a w e l l -  defined tree canopy and are chracterized by dense growths of stunted, wind pruned Picea mariana  which rarely exceed 3 m i n height. Low  shrub species, many of which also occur i n raised bogs, are abundant, while herb and bryophyte growth i s poor. The third forest type recognized i s the Abies balsamea Osrrunda cinnamomea  - Sphagnum cavillaceum  -  or swamp f i r association.  This has a rather limited distribution and occurs low lying sheltered areas, on poorly drained organic s o i l s . Site conditions here are poorer for tree growth than are those of the upland f i r association, and Abies balsamea, lower  the dominant species, forms an open canopy with  densities and higher numbers of standing dead trees than i n  upland f i r stands. Beneath the open canopy, light conditions are . favourable, and the shrub, herb and bryophyte layers are well developed. The forest soils studied are acid and have low levels of t o t a l nitrogen and exchangeable calcium, sodium, potassium and magnesium. Although differences among the s o i l s of the three associations for the chemical factors analysed were few, the organic s o i l s beneath the swamp f i r and the black spruce stands of low lying areas have high moisture contents and probably are poorly aerated. areas.  This could be responsible for poor ,tree growth i n these  iii E a r l i e r workers have noted that the coniferous forests on the Plateau d i f f e r from the mixed climatic climax forests of the lowland areas of Cape Breton, and have suggested that climatic rather than edaphic factors are responsible. In the present study, comparisons of climate for the two areas corroborated this view, indicating that summer maximum and minimum Plateau temperatures are several degrees lower than those of the lowland areas. A second opinion i s that although the Plateau forests have . been c l a s s i f i e d as similar to those of the remainder of Nova Scotia, they are more boreal i n nature. In the present study the Plateau forest associations were found to be f l o r i s t i c a l l y richer than boreal forests i n Newfoundland and southeastern Quebec, but because they contain most of the major species of the boreal forest types, i t i s concluded that they should be considered a southern extension of the boreal forest.  iv  ACKNOWLEDGEMENTS Gratitude i s expressed for invaluable assistance given by a number of persons during completion of the present study.  The wardens  of the Cape Breton Highlands National Park were very cooperative and their assistance i n solving l o g i s t i c problems during the summer f i e l d seasons i s greatly appreciated.  Thanks are also expressed to James  Roy and Paul Forwood for care taken i n the gathering of data. Preparation of the f i r s t draft of this paper was greatly aided by the assistance of Sherran Johnson.  F i n a l l y , I am deeply i n debt to my  supervisor, Dr. Charles B e i l , who generously provided patient instruction and guidance throughout a l l stages of the study.  CONTENTS Page I.  II.  III.  IV.  INTRODUCTION 1.  Objectives  1  2.  Previous Investigations  2  3.  The Study A r e a  . . .  3  METHODS 1.  V e g e t a t i o n Sampling  17  2.  Vegetation Analysis.  17  3.  Soil Analysis  21  4.  C l i m a t i c Measurements  22  THE CLIMATE OF THE PLATEAU 1.  Temperatures  25  2.  Precipitation.  3.  Wind . . .  32  4.  R e l a t i v e Humidity  35  5.  Discussion . .  35  . .  29  DESCRIPTIONS OF THE FOREST ASSOCIATIONS 1.  The Upland F i r A s s o c i a t i o n .  '. 44  2.  The B l a c k Spruce A s s o c i a t i o n  49  3.  The Swamp F i r A s s o c i a t i o n  53  4.  S u c c e s s i o n a l Communities  57  5.  Discussion  60  6.  Comparison o f t h e P l a t e a u A s s o c i a t i o n s w i t h B o r e a l F o r e s t s i n E a s t e r n Canada  68  .vi  (  Page V.  VI.  VII. VIII. IX. X. XI.  FOREST SOILS 1.  Morphological  Characteristics.  . . . .  2.  P h y s i c a l and Chemical C h a r a c t e r i s t i c s .  3.  Discussion  80 89 105  AUTECOLOGY OF MAJOR TREE SPECIES 1.  Abies  balsamea  2.  Picea  maviana  3.  Picea  glauca  4.  Betulo.  5.  Discussion  (Balsam F i r ) .  106  ( B l a c k Spruce)  .  (White S p r u c e ) .  papyrifera  . .  (White B i r c h )  CONCLUSIONS.  119 i20 121  FINAL DISCUSSION SUMMARY.  108  128 . •  133 -143  LITERATURE CITED  145  APPENDICES  149  LIST OF TABLES Table 1.  Page Climate summaries f o r D.O.T. s t a t i o n s i n northern Cape Breton  8  2.  D e s c r i p t i o n of vegetation l a y e r s  3.  The Domin-Krajina scale of cover abundance  4.  Location and d e s c r i p t i o n of meteorological station's  23  5.  D a i l y maximum and minimum temperatures a t P l a t e a u and D.O.T. s t a t i o n s . D a i l y temperature ranges f o r the Cape Breton Plateau  26  and D.O.T. s t a t i o n s  30  7.  P r e c i p i t a t i o n t o t a l s f o r the Cape Breton P l a t e a u . . . . . .  31  8. 9.  Wind measurements on the Cape Breton Plateau D i s t r i b u t i o n of constant species among f o r e s t associations  34  6.  10. 11. 12. 13.  . 19  '. 61  P h y s i c a l and chemical c h a r a c t e r i s t i c s of upland f i r soils  88  P h y s i c a l and chemical c h a r a c t e r i s t i c s of swamp f i r soils.  90  P h y s i c a l and chemical c h a r a c t e r i s t i c s of b l a c k spruce s o i l s i n depressions  92  P h y s i c a l and chemical c h a r a c t e r i s t i c s of b l a c k spruce s o i l s on ridges  14.  18  Mensurational data f o r major tree species. . . .  . 94 109  viii  LIST OF FIGURES Figure  Page  1.  The Plateau from the Lox-zlands  2.  The Plateau from McKenzie Mountain  3.  Map of the study area  4 '. . . .  4 6  4. Maximum and minimum temperatures at Plateau station 01. .. . 28 5.  Maximum and minimum temperatures at Plateau station 02. . . 28  6. Maximum and minimum temperatures at Plateau station 11. . . 28 7. Precipitation totals at Cape Breton Plateau climatic stations  . 33  8. Maximum and minimum temperatures at Cheticamp, N.S. ; . . .  39  9. Maximum and minimum temperatures at Ingonish Beach, N.S  39  10.  Maximum and minimum temperatures at Buchans, Newfoundland  41  11.  Precipitation totals at D.O.T. stations  12.  The upland f i r association  45  13.  Understory vegetation i n an unshaded area  47  14.  Understory vegetation i n a shaded area  47  15.  Dryopteris  16.  Black spruce stands developed around open peat bogs . . . .  17.  Black spruce stand showing wind-trimmed trees  18.  Black spruce stand showing the abundance of low shrubs. . . 52  19.  A stand of the swamp f i r association  20.  A successional community i n which Abies i s dominant  spinuZosa  ...  i n an upland f i r stand  42  48 50  . . 50  56 balsamea  58  ix  Figure  21.  Page  A  s u c c e s s i o n a l community  papyrifara  Betv.la  i n which  58  i s dominant  22.  A soil  profile  i n an upland  23.  A soil  profile  i n a swamp f i r s t a n d  24.  D i s t r i b u t i o n o f Abies diameter  25.  26.  among  81  . .  83  stem m  classes  Regression  balsamea  o f h e i g h t v s . D.B.H. d a t a  for  . . . . . . . . .  o f h e i g h t v s . D.B.H. d a t a  for  114  Abies  i n the upland f i r a s s o c i a t i o n  D i s t r i b u t i o n o f s t a n d i n g dead among d i a m e t e r c l a s s e s  Abies  113  Abies  i n t h e swamp f i r a s s o c i a t i o n  Regression  balsamea.  28.  bo.lsamea  G r a p h o f a g e v s . D.B.H. o f Abies  balsamea  27.  f i r stand  115  balsamea 117  1  I.  INTRODUCTION  1.  Objectives  A l t h o u g h s e v e r a l s t u d i e s have been made o f the Cape B r e t o n Plateau  f o r e s t s , knowledge of them i n many ways s t i l l remains  deficient.  For the most p a r t , i n v e s t i g a t o r s have r e c o g n i z e d  communities on the P l a t e a u  on the b a s i s of t r e e s p e c i e s  g i v i n g inadequate c o n s i d e r a t i o n vegetation. Forest  composition,  to c h a r a c t e r i s t i c s o f u n d e r s t o r y  E n v i r o n m e n t a l f a c t o r s have been p o o r l y  s o i l s o f the area have been p o o r l y  (191S) and Comeau (1971)  investigated.  s t u d i e d , and o n l y  gathered weather data.  Finally,  s e v e r a l w r i t e r s have suggested t h a t the P l a t e a u v e g e t a t i o n to t h e b o r e a l f o r e s t s o f e a s t e r n  Canada and should  f o r e s t s and n e i g h b o u r i n g b o r e a l  Nichols although i s similar  be c l a s s e d as p a r t  of the same, no d e t a i l e d comparisons have been made between  The p r e s e n t  forest  Plateau  regions.  study was designed t o employ p h y t o s o c i o l o g i c a l  methods to q u a n t i t a t i v e l y and q u a l i t a t i v e l y c h a r a c t e r i z e t h e s t r u c t u r e and  c o m p o s i t i o n o f f o r e s t a s s o c i a t i o n s on the P l a t e a u .  this information  i s r e l a t e d to data obtained  Furthermore,  from a n a l y s e s  o f s o i l s and  c l i m a t e , and e c o l o g i c a l r e l a t i o n s h i p s d e t e r m i n i n g the i d e n t i t y o f f o r e s t communities a r e examined. w i t h those o f v e g e t a t i o n southeastern  studies  Results  from t h i s study a r e compared  i n Newfoundland  Quebec ( L i n t e a u , 1955), and Labrador  (Damman, 1964), ( W i l t o n , 1964).  2. Few Plateau.  vegetation  One  Investigations  s t u d i e s have been conducted on  of the e a r l i e s t was  which o n l y v e r y noted.  Previous  general  a f o r e s t survey by Macoun (1898) i n  c h a r a c t e r i s t i c s of the f o r e s t v e g e t a t i o n  In a l a t e r study  (Fernow et ^1. , 1912)  examined as p a r t of an economic study of the The by N i c h o l s  first  (1918).  detailed vegetation This included  p l a n t communities and topography, and Several Killam  the Cape B r e t o n  the P l a t e a u  f o r e s t s were  f o r e s t s of Nova S c o t i a .  study of the area was  the r e c o g n i t i o n and  conducted  d e s c r i p t i o n of  a s s o c i a t i o n s , which were r e l a t e d to c l i m a t e  placed  i n a general  forest classification  and  scheme.  l a t e r i n v e s t i g a t i o n s i n c l u d e those o f H a l l (1949) and  (1951) i n which p o l l e n p r o f i l e s from peat bogs on the  were examined i n an attempt to determine the sequence of communities s i n c e g l a c i a t i o n . by C o l l i n s (1950, 1951)  The  present  Plateau  plant  from a s e r i e s of p l o t s l o c a t e d a l o n g  coverage were made.  McDonald  Plateau  f o r e s t s were s t u d i e d  i n which a number o f q u a n t i t a t i v e measurements such as frequency and  were  transects,  density,  (1958) c a r r i e d out  s i m i l a r study of the f o r e s t s l o c a t e d on the upper s l o p e s  a  l e a d i n g to  the  Plateau. The  most r e c e n t  study i s an e c o l o g i c a l a n a l y s i s of  a s s o c i a t i o n s o c c u r r i n g i n r a i s e d bogs on the P l a t e a u which p h y t o s o c i o l o g i c a l methods were used and edaphic f a c t o r s were c o n s i d e r e d  plant  (Comeau, 1971)  both c l i m a t i c and  i n r e l a t i o n to the  vegetation.  in  3  3.  The Study Area  L o c a t i o n and Physiography  . ;  2  Cape B r e t o n , a l a r g e i s l a n d o f over 10,000 km  , forms the  n o r t h e a s t e r n t i p o f Nova S c o t i a and i s c e n t e r e d around a p o i n t a t a p p r o x i m a t e l y 46°N and 61°W.  I t i s b o r d e r e d by the A t l a n t i c Ocean on  the south and e a s t , and the G u l f o f S t . Lawrence and S t r a i t on the n o r t h and west r e s p e c t i v e l y .  Northumberland  I t s northernmost t i p i s  s i t u a t e d a p p r o x i m a t e l y 80 km southwest o f Newfoundland. The i s l a n d  i s composed of two p e n i n s u l a s , a s m a l l e r s o u t h -  e a s t e r n p o r t i o n formed of g e n t l y r o l l i n g lowlands and s t e e p l y uplands, and a n o r t h e a s t e r n p e n i n s u l a composed of a l a r g e  folded  central  t a b l e l a n d or p l a t e a u surrounded by c o a s t a l lowlands near sea l e v e l i n elevation.  The P l a t e a u , over 30,000 ha i n a r e a , s l o p e s upward from an  average e l e v a t i o n of about 90 m i n the southern p a r t of the i s l a n d to an average of over 450 m at the n o r t h e r n end, and has been c o n s i d e r e d a r e s i s t a n t fragment of an upland r e g i o n once e x t e n s i v e throughout the M a r i t i m e P r o v i n c e s ( G o l d t h w a i t e , 1924). From the Lowlands  the top of the P l a t e a u appears r a t h e r  flat  ( F i g . 1 ) , but i s i n f a c t composed of low r i d g e s and broad s h a l l o w valleys  (Fig.lfc).  Near the edge o f the P l a t e a u t h i s type of  topography i s f r e q u e n t l y i n t e r r u p t e d by steep w a l l e d gorges eroded by streams d r a i n i n g the i n t e r i o r ^ ( F i g . 2 ) . The s i d e s of the P l a t e a u are steep and o f t e n bear l a r g e areas o f t a l u s . The a r e a s e l e c t e d f o r study i s l o c a t e d on the n o r t h e r n p a r t o f the P l a t e a u p a r t l y w i t h i n the Cape B r e t o n H i g h l a n d s N a t i o n a l Park.  Here  the P l a t e a u reaches i t s maximum h e i g h t and has an average e l e v a t i o n o f  4a  Figure 1. The P l a t e a u as seen from the lowlands showing the apparent evenness of the summit. ( Photo by Roy )  Figure 2.  The Plateau as seen from McKenzie Mountain showing stream d i s s e c t i o n . ( Photo by Roy )  4b  5  about 450 m.  V e g e t a t i o n was  approximately  10,000 ha.  of  s t u d i e d i n two  The  f i r s t was  the B i g Southwest Brook, the second (Fig. 3  River  Geology and  locations  c e n t e r e d around the headwaters near  the head of the  Red  ).  Soils  The most r e c e n t G e o l o g i c a l Survey map d e s c r i b e d the bedrock as a combination and  totalling  of the a r e a  of r e s i s t a n t Precambrian  f e l d s p a r s c h i s t s and c h l o r i t e g n e i s s e s , t o g e t h e r w i t h  pockets of l i m e s t o n e . the remainder  (Neale,  quartz  localized  These make up most of the bedrock of the P l a t e a u ;  c o n s i s t of v a r i o u s h y b r i d r o c k s formed from l a t e r  i n t r u s i o n s i n t o the Precambrian Although  1963)  igneous  formations.  F e r n a l d (1925) regarded  the P l a t e a u as one  of the  few  areas i n e a s t e r n Canada to remain i c e - f r e e d u r i n g the P l e i s t o c e n e epoch, most w r i t e r s have s i n c e h e l d t h a t the a r e a was  glaciated.  Hichox  (1962)  found d e p o s i t s s u g g e s t i n g the Cape B r e t o n h i g h l a n d s formed the c e n t e r of a l a t e r e t r e a t or l o c a l readvance of the c o n t i n e n t a l i c e s h e e t , Neale  (1963) noted an abundance of g l a c i a l  till  on the P l a t e a u .  The P l a t e a u s o i l s have been p o o r l y s t u d i e d , but be c l a s s e d as shallow, stony P o d z o l s and o r g a n i c peats 1963).  and  i n g e n e r a l can  (Cann et  al.  ,  They are c o n s i d e r e d r e l a t i v e l y u n f e r t i l e , f r e q u e n t l y p o o r l y  d r a i n e d , and are d e r i v e d from a t h i n l a y e r of sandy loam g l a c i a l  till.  \.  Climate The A t l a n t i c P r o v i n c e s are s i t u a t e d  such t h a t f r e q u e n t meetings  take p l a c e between c o n t i n e n t a l a i r from the west, southward moving c o l d air  from Labrador,  and moist  a i r from the A t l a n t i c Ocean.  Consequently,  NORTHERN CAPE BRETON ISLAND ?  S c » l * I X.5 Kilo<n*tcrj to I c« or  =L»^^^^c Contour XnWv&l  1:40.000 Kilor»»t»r«  l»0 M»*re»  Figure 3. Map of northern Cape Breton showing the Study Area.  t I M H O  U^tonmt  P M K  -  B.unrfor^  Stu<J«j A r e a s Cllma+lf fti&'tien*  l l l l l ® Ol  storms a r e f r e q u e n t and temperature f l u c t u a t i o n s a r e common. and Brown, 1966).  (Chapman  Winter seasons a r e c o l d and snowy but f r e q u e n t l y  i n t e r r u p t e d by warm p e r i o d s , summers a r e c o o l w i t h common foggy i n t e r v a l s , and growing seasons a r e o f t e n d e l a y e d i n the s p r i n g by the passage o f c o l d a i r from the Labrador  current.  The two m e t e o r o l o g i c a l s t a t i o n s n e a r e s t the study a r e a a r e l o c a t e d a t I n g o n i s h Beach on the east c o a s t of n o r t h e r n Cape B r e t o n and Cheticamp  on the west c o a s t .  Both s t a t i o n s a r e a t lowland  e l e v a t i o n s ; I n g o n i s h Beach has an e l e v a t i o n a t 4.5 m and Cheticamp i s at sea l e v e l .  Ten-year summaries o f temperature f o r I n g o n i s h Beach and  p r e c i p i t a t i o n f o r b o t h areas (Canadian Department o f T r a n s p o r t , 1964, 1965) (Table 1) i n d i c a t e t h a t a t I n g o n i s h Beach temperature i s 51.8°F 35.1°F  t h e mean annual maximum  (10.5°C), the mean annual minimum temperature i s  (1.7°C), and the mean annual average i s 43.1°F  (6.1°C).  F e b r u a r y i s the c o l d e s t month a t t h i s l o c a t i o n , w i t h a mean average temperature of 22.3°F (18.3°C).  (-5.6°C) and J u l y i s the warmest month a t 65.6°F  Mean minimum temperatures a r e below f r e e z i n g f o r f i v e months  of t h e y e a r . The east c o a s t a t I n g o n i s h Beach r e c e i v e s more p r e c i p i t a t i o n than the west c o a s t a t Cheticamp.  On an annual b a s i s , I n g o n i s h Beach  r e c e i v e s an average o f 53.7 i n (136.3 cm) o f r a i n , 126.1 i n (320.3 cm) of snow, and has an average t o t a l p r e c i p i t a t i o n of 66.3 i n (168.3 cm). At Cheticamp  the y e a r l y average i s 29.2 i n (74.1 cm) o f r a i n ,  118.3 i n (300.5 cm) o f snow, and 41.0 i n (104.1 cm) o f t o t a l precipitation.  In January, the w e t t e s t month o f the year a t both  l o c a t i o n s , I n g o n i s h Beach r e c e i v e s an .average t o t a l  precipitation  Table 1. Ten-Year Climatic Summaries for D.O.T. Stations i n Northern Cape Bre  Location  Annual Mean Annual Mean Annual Mean Annual Mean Annual No. of Months Mean Annual Mean Snow (cm.) Total Prewith Mean . Rain (cm.) Average Max. Temp. Min. Temp. cipitation Min. Temp. ( °C) Temp. ( °C) (•°c) (cm.) Below ( °C)  Cheticamp N.S. 46 38'N lat. 61 Ol'W long. elev. 0 m. Ingonish Beach 46 38'N lat. 60 25*W long. elev. 4.5 m.  10.5  1.7  1.7  5.0  74.1  300.5  104.1  136.3  320.3  168.3  00  (80 i n , 20.3  cm)  Few  almost double t h a t of Cheticamp  (4.43  q u a n t i t a t i v e data have been c o l l e c t e d  the P l a t e a u ; no permanent weather s t a t i o n s e x i s t l i m i t e d to those r e p o r t e d  i n vegetation studies.  t h e r e , and  reported  that the mean d a i l y maximum on the P l a t e a u  minimum (48°F) was  lower than at I n g o n i s h  d a i l y temperatures on the P l a t e a u the c o a s t a l Lowlands  Nichols  are  (1918)  (74°F) was  higher  the mean d a i l y  (56°F).  He  f u r t h e r noted  that  showed a l a r g e r mean range (26°F) than  (15°F).  N i c h o l s b e l i e v e d f r e e z i n g temperatures o c c u r r e d d u r i n g a l l months of the year the P l a t e a u o c c u r r e d  records  From temperatures  over a f i v e - d a y p e r i o d i n August, 1917,  (71°F) and  cm).  f o r the c l i m a t e of  recorded  than the c o a s t a l Lowlands at Ingonish  i n , 11.2  and  noted that i n 1915,  on September 8,  on the  Plateau  the'first  frost  on  18 days e a r l i e r than i n the  Lowlands. N i c h o l s d i d not measure p r e c i p i t a t i o n , but observations coast.  that the P l a t e a u r e c e i v e d more r a i n and  He noted t h a t the P l a t e a u had  c l o u d s , but  from  snow than  the  fogs c r e a t e d by  low  s e v e r a l measurements w i t h atmometers i n d i c a t e d t h a t on c l e a r  days e v a p o r a t i o n believed  frequent  suggested  r a t e s were h i g h e r  t h i s d i f f e r e n c e was  weather on the  due  on the P l a t e a u  than at Ingonish.  He  to h i g h winds, a common f e a t u r e of  Plateau.  More r e c e n t c l i m a t i c * measurements were r e p o r t e d by Comeau (1971) who  found t h a t temperature d a t a c o l l e c t e d from a 77-day p e r i o d  from June to September i n 1970 maximum and  showed t h a t b o t h the average weekly  the average weekly minimum temperatures on the P l a t e a u were  s e v e r a l degrees c e n t i g r a d e lower than those at c o a s t a l Lowland  s t a t i o n s Cheticamp and  Ingonish  Beach.  H i s d a t a d i d not,  however,  i n d i c a t e g r e a t d i f f e r e n c e s i n d a i l y temperature ranges among the  three  areas. Comeau r e p o r t e d p e r i o d amounted to 41.12  t h a t p r e c i p i t a t i o n on the P l a t e a u d u r i n g cm,  79%  falling  r e c e i v e d l e s s at t h i s time, 38.53 cm 28.15  cm at Cheticamp.  i n August.  falling  The  at Ingonish  lowland Beach  this areas  and  Comeau suggested these d i f f e r e n c e s i n c l i m a t e  between the P l a t e a u and  Lowland areas were l a r g e enough to produce  differences i n vegetation.  F o r e s t C l a s s i f i c a t i o n of the Area The  f o r e s t s of much of Nova S c o t i a have been  considered  t r a n s i t i o n a l between the b o r e a l c o n i f e r o u s f o r e s t s o f n o r t h e r n and  the deciduous f o r e s t s of the n o r t h e r n  1935).  States  (Nichols,  1918,  T h i s i s because of the presence i n Nova S c o t i a of b o r e a l t r e e  s p e c i e s such as Picea and  United  Canada  glauca,  s p e c i e s such as Acer  americana,  Abies  saccharum,  balsamea, Fagus  and Betula  grandifolia,  papyrifera,. and  c h a r a c t e r i s t i c of the Deciduous F o r e s t Region.  Ulmus Nichols  (1935) termed t h i s t r a n s i t i o n a l r e g i o n the Hemlock-White Pine  -  N o r t h e r n Hardwoods Region. Nichols were d i s t i n c t  (1918) b e l i e v e d t h a t the Cape Breton  Plateau forests  from those of the r e s t of Nova S c o t i a , c o n s t i t u t i n g a I:  southern  extension  of the b o r e a l N o r t h e a s t e r n  F o r e s t C l i m a t i c Formation.  Evergreen  T h i s , he r e p o r t e d , was  Coniferous  shown by  the  absence on the P l a t e a u of many s p e c i e s such as Fagus grandifolia, saccharum, northern  and Cape  Quercus Breton.  rubra,  which were common i n the Lowlands of  Acer  11  Halliday Breton  Plateau  (1937) and  Rowe (1959, 1972)  both p l a c e d the Cape  f o r e s t s i n the A c a d i a n F o r e s t Region, a u n i t s i m i l a r  N i c h o l s ' Hemlock-White P i n e - N o r t h e r n Hardwoods Region. not r e c o g n i z e any b o r e a l c h a r a c t e r i s t i c s among the P l a t e a u n o t i n g the c o n c l u s i o n s of Macoun (1898) who d i s t i n c t l y non-boreal,  considered  to  Halliday did forests,  the f o r e s t s  a f t e r f i n d i n g no p l a n t s shared  i n common w i t h  Labrador. Rowe, however, r e p o r t e d nature,  the P l a t e a u f o r e s t s were b o r e a l i n  and were s i m i l a r to the New  A c a d i a n F o r e s t Region and Collins  Brunswick Upland S e c t i o n of  the Gaspe S e c t i o n o f the B o r e a l F o r e s t Region.  (1951) found t h a t the P l a t e a u f o r e s t s were c h a r a c t e r i z e d  by a dominance o f b o r e a l t r e e s p e c i e s and two  the  f e a t u r e s he c o n s i d e r e d  a s m a l l t o t a l s p e c i e s number,  t y p i c a l of b o r e a l f o r e s t s .  He noted  the  P l a t e a u f o r e s t s were s i m i l a r to b o r e a l f o r e s t s on I s l e Royale, d e s c r i b e d by Cooper (1913) and and  i n Labrador  ( H u s t i c h , 1949;  should be c l a s s e d as p a r t o f the B o r e a l F o r e s t  Formation.  In a c l a s s i f i c a t i o n of the M a r i t i m e P r o v i n c e s ecoregions  and  a distinct  ecoregion,  glauca,  Abies  zones, Loucks (1961) regarded  balsamea,  f o r e s t s of Quebec and Union.  Betula  payrifera,  Newfoundland and  into  the Cape B r e t o n  f o r e s t e d by a m i x t u r e of Picea and  Hare, 1950),  Plateau  mariana,  Picea  s i m i l a r to the  boreal  the n o r t h e r n  t a i g a of the  as  Soviet  (  In summary, a l t h o u g h forest' c l a s s i f i c a t i o n s  the P l a t e a u f o r e s t s appear i n major  ( H a l l i d a y , 1937;  Rowe, 1959,  the t r a n s i t i o n a l A c a d i a n F o r e s t Region, most authors  1972) have  as p a r t of considered  the v e g e t a t i o n to be v e r y s i m i l a r to t h a t of the B o r e a l F o r e s t Region.  12  Since the forests of the Cape Breton Plateau have been regarded by many as similar to the Boreal Forest Region, yet were c l a s s i f i e d as part of the Acadian Forest Region, a comparison between boreal forests in eastern Canada and those of the Plateau i s desirable. This warrants a review of literature describing general features characteristic of eastern boreal forests and of studies of boreal forests in regions near northern Cape Breton. General Characteristics of Boreal Forests in Eastern Canada Boreal forests extend i n northern Canada as a wide belt of vegetation from Newfoundland to the Rocky Mountain f o o t h i l l s .  These  regions are characterized by long harsh winters and short cool summers, and the forests are made up of a few hardy dominants and have low t o t a l species numbers (Hare, 1954). In eastern Canada the boreal forest i s bordered i n the north by the arctic tree line and in the south by the Great Lakes - St. Lawrence Region (Rowe, 1959).  According to Hare (195o), dominant tree  species of boreal forests east of Manitoba include Pioea glauca, mariana,  Larix  banksiana.  stands. balsamifera,  laricina,  Abies  balsamea,  Picea  and in restricted areas, Pinus  Deciduous species are usually abundant only in successional These include Betula and several Alniis  papyrifera,  Populus  tremuloides,  Populus  species.  According to Rowe (1959), i n southeastern sections of the boreal forest, Abies balsamea,  Picea  glauca,  and Betula  papyrifera  the most abundant tree species on well drained mineral s o i l s . balsamea  are Abies  i s commonly the dominant species here whereas forests occurring  on p o o r l y d r a i n e d m i n e r a l and mariana.  Larix  laricina  numbers.  In n o r t h e r n  organic  i s u s u a l l y present r e g i o n s of Quebec and  c o n d i t i o n s are more severe, P. P.  glauca,  A.  favourable  balsamea  mariana  B.  and  Pioea  s o i l s are dominated by on these  s i t e s but  i n smaller  O n t a r i o , where c l i m a t i c  i s dominant i n most areas  papyrifera  are r e s t r i c t e d  and  to the most  s i t e s such as r i v e r v a l l e y s (Rowe, 1959).  Hare (1950) suggested p l a n t a s s o c i a t i o n s c o u l d be i n boreal f o r e s t s only with d i f f i c u l t y , i s s m a l l and  recognized  s i n c e the t o t a l number o f  s o i l s are h i g h l y v a r i a b l e .  He  suggested i n s t e a d  species  the  r e c o g n i t i o n of t h r e e broad s t r u c t u r a l types among b o r e a l f o r e s t s east Manitoba.  The  most n o r t h e r l y of these  r e g i o n in. which tundra Quebec.  Permafrost  and  i s the f o r e s t Tundra Ecotone, a  b o r e a l f o r e s t meet i n n o r t h e r n  i s common here,  of  and  forests, limited  f a v o u r a b l e a r e a s , are composed m o s t l y of Piaea  Labrador  and  to the most  mariana.  Immediately  south of t h i s zone i s the Open B o r e a l Woodland Zone, c h a r a c t e r i z e d by stands  of w i d e l y  spaced Piaea  v e g e t a t i o n i n appearance and l i c h e n s and  ericaceous  mariana. has  shrubs.  s t r u c t u r e i s produced by  T h i s type resembles savannah  a ground v e g e t a t i o n dominated  Hare suggested t h i s p e c u l i a r stand  the h o r i z o n t a l r o o t i n g h a b i t of the  response to c o n d i t i o n s i n which temperatures i n a l l but of s o i l a r e too low  f o r moisture e x t r a c t i o n .  Abies  stands  balsamea,  trees, a  the upper l a y e r s  The most s o u t h e r l y of  t h r e e i s the Main B o r e a l F o r e s t Zone, i n which p r o d u c t i o n h i g h e s t and  mariana,  and Picea  glauea.  The  southern  by boundary  of the zone i s marked by an i n t r u s i o n of n o n - b o r e a l s p e c i e s such as  Thuja oooidentalis,  Pinus  strobus,  Fraxinus  nigra,  the  i s the  are composed of c l o s e d t r e e l a y e r s dominated  Picea  by  and Betula  lutea.  14  Hare (1950) found that while no c o r r e l a t i o n appeared between these zones and moisture regions, they did correspond to thermal e f f i c i e n c y or potential evapotranspiration (P.E.) (Thornthwaite, 1948). The northern border of the Forest-Tundra Ecotone followed a P.E. isopleth of 12.0 to 12.5 i n and the southern boundary of the Main Boreal Forest zone was similar to a P.E. of 18.5 i n to 19.0 i n . LaRoi (1967) examined the vasular f l o r a of 60 stands i n 24 sections of the Boreal Forest Region recognized by Rowe (1959).  He  reported that the number of constant species was small, and although 291 species were recorded, only 6% occurred i n 60% or more of the stands. Stands dominated by Picea  glauca  and Abies  more species than those dominated by Picea  balsamea  generally contained  mariana,  and species  d i v e r s i t y was greatest i n south-central stands north of the Great Lakes. In spruce-fir stands Abies Saskatchewan, Picea papyrifera  glauca  balsamea  was present throughout, and  Betula  was an important associate east of the Rocky Mountain  h i l l s and south of Great Slave Lake. balsamifera  was common east of  Populus  tremuloides  foot-  and Populus  occurred i n most of the spruce-fir stands west of central  Ontario, and Picea  mariana,  although a frequent subdominant of central  stands was uncommon i n eastern and western areas.  Pinus  banksiana  was  found i n only four stands, located i n Saskatchewan and i n Ontario. Black spruce stands east of Manitoba commonly had Abies balsamea  as an associate.  Picea  glauca,  this type i n the A t l a n t i c Provinces.  however, was rare i n stands of  15  Eastern Boreal Forest  Studies  Newfoundland Damman (1964) c a r r i e d out an e c o l o g i c a l study  of the f o r e s t s  of the E x p l o i t s R i v e r i n c e n t r a l Newfoundland, an a r e a c l a s s i f i e d Rowe (1959) as p a r t of the B o r e a l F o r e s t Region. p h y t o s o c i o l o g i c a l methods i n w h i c h , f i v e subdivided  study  employed  a s s o c i a t i o n s were d e s c r i b e d  into various subassociations. and  The  by  His r e s u l t s  and  presented  floristic  composition  c h a r a c t e r i s t i c s p e c i e s groups f o r each  estimates  of cover-abundance f o r each s p e c i e s , d e s c r i p t i o n s of  profiles,  and  type,  soil  a d i s c u s s i o n of e c o l o g i c a l r e l a t i o n s h i p s among the p l a n t  communities. Southeastern  Quebec  Linteau  (1955) c o n s t r u c t e d  a s i t e c l a s s i f i c a t i o n of the f o r e s t s  of s o u t h e a s t e r n  Quebec, n o r t h of the St. Lawrence R i v e r , i n the  F o r e s t Region.  S i t e types were r e c o g n i z e d  according  to dominant  i n v a r i o u s v e g e t a t i o n l a y e r s , and were d e s c r i b e d i n d e t a i l s p e c i e s abundance, presence l i s t s of s p e c i e s .  (frequency)  and  Boreal  using  s o c i a b i l i t y as w e l l  These types were r e l a t e d to a number of  species  as  site  c o n d i t i o n s i n c l u d i n g s o i l s and were grouped i n t o s i x major u n i t s .  Labrador A broad c l a s s i f i c a t i o n of the f o r e s t s of Labrador was Wilton  made by  (1964) i n which, through a m o d i f i c a t i o n of an e a r l i e r work  ( H u s t i c h , 1949), f i v e f o r e s t types were r e c o g n i z e d .  Wilton's  objective  16  was t o c r e a t e site  conditions,  ecological forest site  a classification  f o r the e n t i r e area,  description of plant  types  of p r o d u c t i v i t y types,  communities.  a r e consequently broad,  conditions,  rather  correlated  with  t h a n make a d e t a i l e d Descriptions  and c o n s i s t  ofh i s  of descriptions of  s t r u c t u r a l c h a r a c t e r i s t i c s , and l i s t s  o f common  species. These of  boreal  three  studies  f o r e s t communities.  compared w i t h claims  that  Forest  Region.  then,  present  In following  r e s u l t s of the present  the Plateau  study,  f o r e s t s should  fairly  detailed  sections,  these a r e  i n an attempt  be c l a s s e d  descriptions  as part  to judge of the Boreal  17  I I . METHODS 1. Vegetation Sampling A preliminary survey of the study area was made prior to sampling.  This indicated the presence of three broad forest types  distinguished by topographic position, physiognomy, and dominant species.  Stands that were topographically and f l o r i s t i c a l l y uniform  and were free from extensive disturbance were selected for study from these types.  In addition to these, three disturbed areas with  successional vegetation were examined. Stands were sampled using single plots subjectively located i n areas representative of the stand as a whole.  Stands with well  developed tree layers were sampled with plots measuring 20 m by 20 m, and those lacking tree layers with 10 m by 10 m plots. 2. Vegetation Analysis Seven vegetation layers were recognized, based on height and physiognomy (Table 2).  The extent of development of each layer was  determined by an estimate of total percentage cover.  Species were  l i s t e d for each layer and were rated with the 11-point Domin-Krajina scale of cover-abundance (Becking, 1957) (Table 3).  These figures were  converted to percentage cover using the mid-point of each coverabundance class. Tree species densities were determined by layer, and various  Table 2 .  D e s c r i p t i o n of Vegetation Layers.  Height  Code  Physiognomy  Trees  Shrubs  A  l  A  2  B  l  B  2  •,  Limits  9 m or g r e a t e r 3.5 m t o 9 m  1. 8 m t o 3.5 m 30 cm t o 1.8 m  Herbs and Dwarf Shrubs  C  l e s s than 30 m  Bryophytes  Dw  growing on wood  Dh  growing on humus  and L i c h e n s  Table 3.  Class  The Domin-Krajina Scale of Cover-Abundance (Becking, 1957).  Cover-Abundance Limits  Class Midpoint (% coverage)  +  single occurrence  0.5%  1  seldom, cover negligible  1.0%  2  very scattered, cover negligible  2.0%  3  scattered, cover to 5% of plot  2.5%  4  common, cover 5% to 10%  7.5%  5  often, cover 10% to 20%  15.0%  6  very often, cover 20% to 30%  25.0%  7  abundant, cover 30% to 50%  8  abundant, cover 50% to 75%  62.5%  9  abundant, cover 75% to 95%  85.0%  10  abundant, cover 95% to 100%  97.5%  40.0%  20 tree measurements were made including the D.B.H. (diameter at breast height) of a l l trees and determinations of ages and heights of trees selected from the range of diameter classes.  In addition, densities of  standing dead and wind-thrown trees were noted. F l o r i s t i c a l l y similar stands were grouped subjectively into associations.  Descriptions of these are presented i n association  tables (Appendix I) i n which species are l i s t e d , by layer, i n order of decreasing constancy.  Constancy i s an expression of the frequency with  which a species was found i n a particular association.  Species of equal  constancy are arranged i n decreasing order of average cover-abundance. Computation of these averages was such that only stands i n which a particular species occurred were included, thus avoiding exceptionally low values for species with low constancy. In addition to the above tables, a summary table (Table 9 ) i s presented i n which constant species (those occurring i n 70% or more stands) are arranged such that for each association characteristic species groups are formed. Vascular plants were identified by Dr. C. E. B e i l , University of B r i t i s h Columbia, and the author. Roland and Smith (1969).  Nomenclature for these follows  Bryophytes excluding species of Sphagnum were  identified by Dr. R. R. Ireland, National Museum of Canada, Ottawa, and Dr. C. E. B e i l .  Sphagnum  University of Toronto.  species were determined by Dr. J. H. Sparling,  Moss nomenclature i s according to Crum et  at.  (1973) and liverworts were named according to Schuster (1953). Several lichen determinations were made by Dr. C. E. B e i l , and follow Hale and Culberson (1970).  A reference collection of vascular plants  collected i n the f i r s t f i e l d season are housed at the E. C. Smith Herbarium Acadia University, N.S.; those collected i n the second season are located with the bryophytes and lichens at the University of B r i t i s h Columbia. 3.  S o i l Analysis  Soil samples were taken by horizon from a single p i t dug i n each vegetation plot, and profiles were described and c l a s s i f i e d according to the Canadian System of S o i l Classification (Canada Dept. of Agriculture, 1970).  Samples were a i r dried, sieved, and the less than  2 m fraction retained for analysis.  A l l analyses, aside from those  designated otherwise, were performed by the author. Selected s o i l samples were analysed for t o t a l nitrogen ( %) and total phosphorus (ppm) using a Technicon Auto Analyzer preceded by wet ashing i n sulphuric acid and hydrogen peroxide.  These determinations  were made by the s o i l s laboratory, Nova Scotia Dept. of Agriculture, Truro, N.S. The exchangeable cations sodium, magnesium, potassium, and calcium were gravimetrically extracted from 50 g s o i l samples using neutralized 1 N sodium acetate solutions (Jackson, 1958).  Cation  concentrations were measured with an atomic absorption spectrophotometer (Perkin-Elmer, Model 303) and expressed as meq/100 g of s o i l . Cation Exchange Capacities were determined for several s o i l samples according to the sodium saturation method (Jackson, 1958). These results were expressed as meq/100 g of s o i l . Percent organic matter was determined as the loss of weight following ignition of s o i l samples at 400°C. Selected samples collected  22  i n 1970 were a n a l y z e d by the S o i l s L a b o r a t o r y , Nova S c o t i a Department of A g r i c u l t u r e ; d e t e r m i n a t i o n s f o r those taken i n 1971 were made by the author. S o i l pH r e a d i n g s were made w i t h a pH meter (Radiometer, 25) on 1 : 2.5 s o i l  : water suspensions  prepared  from l O g s o i l  Model samples.  Texture a n a l y s e s were c a r r i e d out on s e l e c t e d s o i l s u s i n g the hydrometer method (Bouyoucos, 1951). used  U.S.D.A. t e x t u r a l c l a s s e s were  i n which the l i m i t s f o r sand a r e 2.00 mm to 0.55 mm,  silt,  0.05 mm  to 0.002 mm and c l a y , l e s s than 0.002 mm. A soil's ability was  to r e t a i n water i n a form u s a b l e by p l a n t s  measured as p e r c e n t a v a i l a b l e water, the d i f f e r e n c e between  permanent w i l t i n g percentage 1960).  and f i e l d  c a p a c i t y (Buckman and Brady,  A p r e s s u r e p l a t e e x t r a c t o r was used  to determine  b o t h of t h e s e ,  s u b j e c t i n g s o i l s f o r 48 hours t o one t h i r d atmosphere o f p r e s s u r e f o r field  c a p a c i t y , and 15 atmospheres f o r permanent w i l t i n g  4.  percentage.  C l i m a t i c Measurements  S e v e r a l c l i m a t i c s t a t i o n s were e s t a b l i s h e d on the P l a t e a u d u r i n g the 1970 and 1971 f i e l d  seasons.  were as near as p o s s i b l e to the sampling  The l o c a t i o n s o f these district.  S i n c e the number of  m o n i t o r i n g instruments was l i m i t e d , each s t a t i o n d i f f e r e d the types of measurements made (Table 4 ) .  (Fig. 3 )  s l i g h t l y as t o  R e s u l t s from the P l a t e a u  s t a t i o n s were compared w i t h those from Department o f T r a n s p o r t  stations  a l o n g the c o a s t of n o r t h e r n Cape B r e t o n and i n C e n t r a l Newfoundland (Table 4 ) . i  Temperatures were monitored  c o n t i n u o u s l y on the P l a t e a u w i t h  23  Tabled .  Location  Location  and D e s c r i p t i o n of M e t e o r l o g i c a l  Period of Measurement  Elevation  Stations  Parameters  Cheticamp, N.S. (DOT S t a t i o n )  46°33'N 61°01'W  0 m  continuous  daily precip., d a i l y min., max., mean temp.  I n g o n i s h Beach, N.S. (DOT S t a t i o n )  46°38'N 60°24'W  4.5 m  continuous  daily precip., d a i l y min., max., mean temp.  Cape Breton P l a t e a u S t a t i o n 01 (open bog)  46°43'N 60°39'W  480 m  June-August 1970 - 77 days  continuous temp., weekly p r e c i p . , weekly wind v e l o c i t y , t o t a l wind.  Cape Breton P l a t e a u 46°42'N S t a t i o n 02 60°36'W (open heath b a r r e n )  510 m  June-August 1970 - 77 days  continuous p r e c i p . , weekly p r e c i p .  Cape B r e t o n P l a t e a u S t a t i o n 03 ( f i r forest)  46°42'N 60°36'W  480 m  June-August 1970 - 62 days  d a i l y max., min. temp., o c c a s i o n a l r e l . humid.  Cape B r e t o n P l a t e a u S t a t i o n 11 (open bog)  46°60'N 60°40'W  405 m  June-August 1971 - 54 days  c o n t i n u o u s temp., weekly p r e c i p . , weekly wind v e l o c i t y , t o t a l wind.  Cape B r e t o n P l a t e a u 46°50'N S t a t i o n 12 60°24'W (open heath b a r r e n )  225 m  June-August 1971 - 54 days  weekly p r e c i p . , weekly max., min. temp.  Cape B r e t o n P l a t e a u 46°45'N S t a t i o n 13 60°51'W (open heath b a r r e n )  420 m  June-August 1971 - 54 days  weekly p r e c i p . , weekly max., min. temp.  Buchans, Newfoundland (DOT S t a t i o n )  48°45'N 56°50'ti  270 m  continuous  daily precip., d a i l y max., min. temp.  Glenwood, Newfoundland (DOT S t a t i o n )  49°00'N 54°50'W  60 m  continuous  daily precip., d a i l y max., min. temp.  the thermographs housed at ground l e v e l i n Stevenson screens. Precipitation was measured weekly i n stainless steel rain gauges, and cumulative miles of wind were recorded with a t o t a l i z i n g anemometer placed at a height of 2 m above ground l e v e l .  These wind data were  supplemented with weekly measurements of wind velocity. The present project was, i n 1970, undertaken as part of a broad study of the Plateau, which included other vegetation types. Weather monitoring during this period was a cooperative effort and consequently some of the data summarized below was also presented by Comeau (1971).  25  III.  THE CLIMATE OF THE PLATEAU  The r e g i o n a l c l i m a t e o f ah a r e a i s an i m p o r t a n t a s p e c t o f environment f o r v e g e t a t i o n .  F a c t o r s such as temperature  regimes,  p r e c i p i t a t i o n , and r e l a t i v e h u m i d i t y p l a y c r u c i a l r o l e s i n t h e d e t e r m i n a t i o n o f s i t e c o n d i t i o n s under which v e g e t a t i o n d e v e l o p s .  A  s t u d y o f c l i m a t i c c o n d i t i o n s on t h e Cape B r e t o n P l a t e a u i s p a r t i c u l a r l y v a l u a b l e from t h e v i e w p o i n t t h a t d i f f e r e n c e s i n v e g e t a t i o n between t h e P l a t e a u and Lowland areas of Cape B r e t o n have been a t t r i b u t e d t o c l i m a t e ( N i c h o l s , 1918; C o l l i n s , 1950; Comeau, 1971). In a d d i t i o n t o t h e summaries of temperature,  wind and  p r e c i p i t a t i o n p r e s e n t e d below, t h e o r i g i n a l r e s u l t s o f c l i m a t i c measurements a r e g i v e n i n Appendix 1.  III.  Temperatures  A summary o f d a i l y maximum and minimum t e m p e r a t u r e s on t h e P l a t e a u d u r i n g t h e summers of 1970 and 1971 (Table 5)  i n d i c a t e s that  the l o w e s t temperatures o f t h e three-month p e r i o d were r e c o r d e d i n June (0°-C i n 1970, 3°C i n 1971) and t h e h i g h e s t f o r 1970 i n J u l y (31°C) and f o r 1971 i n August (28°C). Mean maximum t e m p e r a t u r e s f o r t h e s t a t i o n s i n 1970 a r e h i g h e s t i n J u l y and n e a r l y e q u a l i n June and August (Table 5 ) w h i l e those f o r s t a t i o n 11 i n 1971 a r e lowest i n June and h i g h e s t i n August.  Means of  d a i l y minimums a r e l o w e s t i n June f o r b o t h y e a r s , and, w i t h t h e e x c e p t i o n of s t a t i o n 03, a r e h i g h e s t i n August.  Table 5 Summaries of Daily Maximum and Minimum Temperatures at Plateau Stations and D.O.T,. Stations at Ingonish Beach, Cheticamp, and Buchans Monthly Mean (°C)  Location  Month  Location  June 1970 (17 days)  C.B. Plateau Station 01 C.B. Plateau Station 02 C.B. Plateau Station 03 C.B. Plateau Station 11  Daily Daily Daily Daily Daily Daily Daily Daily  Max. Min. Max. Min. Max. Min. Max. Min.  19.0 8.8 20.6 10.0 20.5 8.7 15.3 8.1  Cheticamp, N.S.  C.B. Plateau Station 01 C.B. Plateau Station 02  Daily Daily Daily Daily  Max. Min. Max. Min.  21.7 11.9 22.1 12.2  Cheticamp, N.S.  June 1971 (06 days) July 1970 (31 days)  Ingonish Beach, N.S. Buchans, Nfld.  Ingonish Beach, N.S. Buchans, Nfld.  (26 days) July 1971 (31 days) August 1970 (29 days)  C.B. Plateau Station 03 C.B. Plateau Station 11  Daily Daily Daily Daily  Max. Min. Max. Min.  22.7 12.7 21.2 12.2  C.B. Plateau Station 01 C.B. Plateau Station 02  Daily Daily Daily Daily  Max. Min. Max. Min.  20.7 12,6 21.2 13.4  Cheticamp, N.S. Ingonish Beach, N.S Buchans, Nfld.  (21 days) August 1971 (16 days)  C.B. Plateau Station 03 C.B. Plateau Station 11  Daily Daily Daily Daily  Max. Min, Max. Min.  19.1 12.3 22.0 15.0  Monthly Mean (°C) Daily Max. Daily Min. Daily Max. Daily Min. Daily Max. Daily Min.  20.4 11.4 21.5 11.6 20.0 7.7  Daily Max. Daily Min. Daily Max. Daily Min. Daily Max. Daily Min,  23.1 14.9 24.5 14.5 21.9 11.4  Daily Max. Daily Min. Daily Max. Daily Min. Daily Max. Daily Min.  22.6 15.3 23.8 . 15.5 21.4 12.2  27 Mean maximum and mean minimum temperatures vary only s l i g h t l y among the three stations established i n 1970.  These were compared  using Duncan's New Multiple Range Test (Steel and Torrie, 1960) and were not found to be significantly different (a = 0.05).  Differences  between means for the 1970 and 1971 stations are larger, but may be related to the fact that only six days of June and 16 days of August were used for measurement i n 1971. Temperature regimes for the areas studied can be further characterized and compared by examining the frequency with which temperatures of various groups occurred. Frequencies are determined for each of 12 three-degree classes, for both daily maximum and minimum temperatures.  Frequencies are expressed as a percentage of the total  number of days involved at each location. Figures 4 and 5 show that the most frequent groups of maximum temperatures at both stations 01 and 02 i n 1970 are those including temperatures from 16°C to 21°C, which occurred with a frequency of 50.7% at station 01 and 43.7% at station 02.  Maximum temperatures below 19°C  were s l i g h t l y more frequent at station 02 (32.7%) than at station 01 (29.9%) and maximums above 25°C also occurred more often at station 02 (31.5%) than at station 01 (22.1%). Minimum temperatures from 7°C to 12°C were most common at station 01, where they occurrjed on 41.6% of a l l days, while at station 02 a s l i g h t l y higher group was most frequent (13°C to 18°C), with a frequency of 48.6%. Minimum temperatures below 10°C were more frequent at station' 01 (36.4%) than at station 02 (29.1%), as were minimums above 15°C (station 01, 28.6%; station 02, 26.4%).  28 , T » m p * r a t v r o Class**  I  E3  M  IV  V  V I VII  VIM  IS  SI  Xlt Tcm^oratvre  Claot««  n  r , nr i  rVSastmwfn  |  1  2 s  i  18  |  IS  Minimum  2*  Figure 4. X Frequency of D a l l y Maximum and Minimus  Figure 6. 2 Frequency of D a i l y Kaxinua and Minimus  Temperatures at Plateau S t a t i o n 01 i n Various Classes  Temperatures at Plateau S t a t i o n 11 i n Various Classe  Temperature Ctoitoft  19  H  i i  Class  >: to  Explanation of F i g u r e *  m rv v vi vn. viu ix X xt xa I  II  III  Maxknvm  IV V VI VII  M•* "  VIII  t •  12 X  SI  »  XII  t J -  f  Mfrtrmwai  i»-  H  Figure 5. 2 Frequency o f D a l l y Maximum and Kintoua T ^ o p c r a t u i ^ at Plateau S t a t i o n 02 i n Various Classes  Tecperat-re bilow 0 0-3 4-6 7-9 10 - 12 13 - 15 16 - 18 19 - 21 22 - 24 25 - 27 28-30 abora 30  29 Maximum temperatures between 19°C and 25°C formed the most frequent group at s t a t i o n 11 i n 1971, w i t h a 56.6% occurrence ( F i g u r e d ) . Maximum temperatures below 19°C at t h i s s t a t i o n (28.4%) were s l i g h t l y lower i n frequency than at s t a t i o n 02, but s i m i l a r to 01. Maximum temperatures above 25°C occurred much l e s s frequently at s t a t i o n 11 (15.1%) than at e i t h e r of the 1970 s t a t i o n s . The most frequent minimum temperatures at s t a t i o n 11 were those from 10°C to 15°C, occurring w i t h a frequency of 50.9%. Minimums below 10°C occurred on fewer days (21.5%) at t h i s s t a t i o n than at s t a t i o n s i n 1970, while those above 15°C had a frequency of 27.5%, s i m i l a r to those of 1970. Averages of d a i l y temperature ranges, or the d i f f e r e n c e s between d a i l y maximum and minimum temperatures (Table 6 ) from 1970 s t a t i o n s are highest i n June i n which means vary from 10.1°C to 11.8°C among the three s t a t i o n s . from 6.7°C to 8.0°C.  August mean ranges are the lowest, varying  D a i l y temperature ranges varied considerably,  ranges at s t a t i o n 02 varying i n June from 4.0°C to 23.0°C, i n J u l y from 1.0°C to 19°C and i n August from 1.0°C to 14.°C. Mean ranges d i d not d i f f e r considerably among the three 1970 s t a t i o n s .  Mean temperature  ranges f o r June and August at s t a t i o n 11 i n 1971 are lower than those for 1970, but these d i f f e r e n c e s again may be produced by the f a c t that few days of these months were'monitored i n 1971.  The mean range f o r  J u l y at s t a t i o n 11 i s s i m i l a r to those of 1970. !  2.  Precipitation  P r e c i p i t a t i o n t o t a l s f o r the three-month period i n 1970 (Table 7 ) v a r i e d considerably between s t a t i o n s 01 and 02; the former  30 Table 6. Summaries o f D a i l y Temperature Ranges at P l a t e a u S t a t i o n s  and D.O.T. S t a t i o n s a t  Ingonish Beach, Cheticamp, and Buchans  Year  Month  1970  June  1971 1970  July  1971 1970  August  1971  I  Station  Mean Range (°C)  Mean Range (°C)  Location  01  10.1  Cheticamp, N.S.  9.0  02  10.5  I n g o n i s h Beach, N. S.  9.8  03  11.8  Buchans,  11  7.1  01  9.8  Cheticamp, N.S.  02  9.9  I n g o n i s h Beach, N. S.  10.0  03  9.8  Buchans,  10.3  11  9.0  01  8.0  Cheticamp, N.S.  7.0  02  7.8  I n g o n i s h Beach, N. S. .  8.3  03  6.7  Buchans,  9.9  11  7.0  Nfld.  Nfld.  Nfld.  12.5  8.2  31 T a b l e 7. Precipitation Totals and  at Plateau  Stations  D.O.T. S t a t i o n s a t I n g o n i s h Beach,  Cheticamp, and Buchans  from June to August  Total Precipitation (cm)  Total Precipitation (cm)  Year  No. of Days  1970  79  01  40.90  I n g o n i s h Beach, N.S.  38.48  79  02  30.50  Cheticamp,  26.26  44  11  31.32  Buchans,  44  12  28.17  44  13  28.70  1971  I  Station  Station  N.S.  Nfld.  37.40  32 received 40.90 cm, the l a t t e r only 30.50 cm. In 1971 a l l stations received similar amounts of precipitation.  These were similar to that  of station 02 i n 1970, but as the 1971 period of measurement was 33 days shorter than that of 1970, t o t a l precipitation for the two years may have differed. The distributions of r a i n f a l l recorded at station 01 i n 1970 and at 11 i n 1971 (Figure 7 ) were not uniform. In 1970 r e l a t i v e l y l i t t l e rain was received i n July and early August, and 70% of the t o t a l f e l l within a 14-day period i n August.  In 1971, a peak i n r a i n f a l l i n  early July was followed by a period of r e l a t i v e l y low precipitation for the remainder of the month, and a r i s e similar to that of 1970 occurred during the middle of August.  R a i n f a l l distributions at other Plateau  stations were similar to those mentioned above. 3. Wind In the 17-day measurement period of June, 1970, a t o t a l of 4700.9 km of wind was measured at station 01 (Table 8 ), equivalent to an average of 334.1 km per day or 13.0 km per hour.  A number of spot  wind velocities were determined; of those taken i n June, the highest was 28.7 km per hour.  9013.1 km were recorded at this station i n July,  equal to an average of 300.1 km per day, or 12.4 km per hour. The maximum measured velocity for this month was 25.1 km/hr. Wind I,  measurements i n August, 1970 resembled those of July. Wind was recorded for only s i x days i n June 1971 at station 11 (Table 8 ); during this period the mean per day was 236.2 km and per .i  hour was 9.7 km. Much less wind blew i n July 1971 than i n July of the  16 i  June 13  to  19  to  July 27  Figure  to  6  to  August 13  to  6  7. Weekly P r e c i p i t a t i o n T o t a l s Plateau Climatic  to  13  to  a t Cape  19  to  Breton  Stations.  00  w  j i  34  T a b l e 8. Summaries of Wind Measurements on the Cape Breton P l a t e a u , a t s t a t i o n s and  Month June  July  August  01 (1970)  11 (1971) d u r i n g June t o August  Station  No. o f Days  Mean per day ' , (Km)  Mean per hr (Km)  Maximum per h r (Km)  Monthly Total (Km)  01  17  334.1  13.0  28.7  4700.9  11  06  236.2  9.7  16.3  2126.2  01  31  300.1  12.4  25.1  9013.1  11  31  224.6  9.3  19.3  6739.3  01  29  270.5  12.1  27.4  8925.8  11  16  262.4  11.3  19.3  3675.6  previous year; i n 1971 a t o t a l of 6739.3 km was recorded, equivalent to 224.6 km/day, or 9.3 km/hr. The maximum spot reading for this period was 19.7 km/day. The mean wind per day and per hour for August 1971 was only s l i g h t l y lower than that of the previous year. 4.  Relative Humidity  The only relative humidity readings taken on the Plateau during the study period were those made by Comeau (1971) twice daily beneath an Abies balsamea of 1970.  canopy over a 21-day period in June and July  Morning readings averaged 81.7% and ranged from 41.0% to  93.0%, while evening readings averaged 72.4% and varied from 42.0% to 93.0%. Although daily weather conditions were not recorded, low cloud banks were commonly present on the Plateau as dense fog.  Little  additional precipitation was measured at these times, but exposed vegetation nevertheless appeared to receive considerable amounts of moisture. 5.  Discussion  The preceding results show that during the three-month period in 1970, minimum temperatures were lowest i n June and highest i n August, while maximum temperatures were highest i n July.  Although  temperature means did not d i f f e r greatly between the two stations i n 1970, frequencies of maximum and minimum temperature groups did. Both very low and high daily maximum temperatures were more common at station 02 than at station 01, but low and high minimum temperatures were more frequent at station 01.  In other words, over the three month  36  p e r i o d of measurement, maximum temperatures at s t a t i o n 01 were g e n e r a l l y more s t a b l e than at s t a t i o n 02, r e v e r s e was  where extremes were more common.  t r u e f o r minimum temperatures.  S t a t i o n s 01 and  d i f f e r e d markedly i n terms of l o c a t i o n ; 01 was and  02 on a dry b a r r e n  area.  temperatures were g e n e r a l l y s i m i l a r .  used i n 1971.  T h i s may  speeds recorded  being  The  i n the two  d i f f e r e n c e s t h a t were  a short  period  i n August.  by r a p i d r u n o f f and  d u r i n g both y e a r s was  very  low  rainfall  periods,  i n some areas at times of i n June  D i f f e r e n c e s , however, were l e s s than t h r e e  High wind v e l o c i t i e s are p r o b a b l y more c r i t i c a l d u r i n g  blasting.  Extensive  around r a i s e d bogs on Tne  i s subjected  to d r i f t i n g  high and km  the P l a t e a u  per  winter  snow and  damage of t h i s type i s common i n v e g e t a t i o n  ice in  ( N i c h o l s , 1913).  r e s u l t s of t h i s study d e s c r i b e  f o r the summers of 1970  so  Such i r r e g u l a r i t i e s i n d i s t r i b u t i o n  erosion  months, when exposed v e g e t a t i o n  unevenly  i n the three-month p e r i o d d i d  Mean wind v e l o c i t i e s were g e n e r a l l y h i g h e s t  lowest i n August.  than t h a t  areas.  could create r e l a t i v e l y dry conditions during  climate  than i n  a l s o have accounted f o r d i f f e r e n c e s i n wind  d i s t r i b u t e d ; most of the r a i n f a l l i n g  hour.  i n 1971  l o c a t e d i n a much l a r g e r bog  P r e c i p i t a t i o n on the P l a t e a u  rainfall.  have  have been produced by d i f f e r e n c e s i n l o c a t i o n , the  measurement s i t e i n 1970  followed  areas may  A l t h o u g h h i g h maximum and  low minimum temperatures were s l i g h t l y l e s s f r e q u e n t  during  bog,  Thermographs were l o c a t e d a t ground  s t r o n g l y a f f e c t e d the temperatures r e c o r d e d .  observed may  02  located i n a raised  l e v e l , hence d i f f e r e n c e s i n heat c o n d u c t i v i t y of the two  1970,  The  and  1971,  a s p e c t s of the  but  are not  Plateau  necessarily  and  37  typical.  In a d d i t i o n , no q u a n t i t a t i v e i n f o r m a t i o n as to w i n t e r  conditions exist.  A long-term,  year-round  climatic  study would be n e c e s s a r y f o r  a c l e a r u n d e r s t a n d i n g of the c l i m a t e o f the a r e a .  Comparisons w i t h Lowland Cape B r e t o n and Newfoundland Both N i c h o l s (1918) and Comeau (1971) suggested the P l a t e a u i s d i f f e r e n t  the c l i m a t e of  from t h a t o f Lowland s t a t i o n s a t I n g o n i s h  Beach and Cheticamp on the c o a s t , and Loucks (1962) b e l i e v e d the P l a t e a u to be c l i m a t i c a l l y s i m i l a r to Buchans, Newfoundland.  I t seems  a p p r o p r i a t e , then, t o compare the r e s u l t s f o r the P l a t e a u p r e s e n t e d above w i t h r e c o r d s f o r the same p e r i o d from D.O.T. s t a t i o n s a t these locations.  S i n c e the p e r i o d o f measurement on the P l a t e a u i n 1970 was  l o n g e r than t h a t o f 1971, the r e s u l t s from the former year a r e used f o r comparisons. These comparisons  must, however, be t r e a t e d w i t h r e g a r d g i v e n  to the f a c t t h a t w h i l e instruments on the P l a t e a u were l o c a t e d a t ground l e v e l ,  those a t D.O.T. s t a t i o n s were p o s i t i o n e d a t a h e i g h t o f  4 ft.  (1965) suggested  Geiger  depending degrees  t h a t such d i f f e r e n c e s i n h e i g h t c o u l d ,  upon weather c o n d i t i o n s , produce  i n temperature.  Adjustments  cannot  the P l a t e a u , s i n c e a p p a r e n t l y temperature consistent.  d i f f e r e n c e s of several be made to d a t a c o l l e c t e d on  d i s c r e p a n c i e s a r e not  In s p i t e o f t h i s * p r o b l e m , i t does seem worthwhile t o  compare c l i m a t i c measurements from the Lowland areas of Cape Breton and c e n t r a l Newfoundland w i t h those o f the P l a t e a u . In 1970, June maximum temperatures stations differed  little.  a t the P l a t e a u and Lowland  At Cheticamp and I n g o n i s h Beach these  38 averaged 20.4°C and 21.5°C respectively (Table 5 ), less than three degrees higher than means for Plateau stations. month at the Lowland on the Plateau.  Stations,  Mean minimums for this  however, were 1° to 3° higher than those  Similarly, i n July and August averages of both  minimum and maximum temperatures at both Cheticamp and Ingonish Beach were 2° to 3° higher than those for Plateau stations. When the frequency of occurrence of various maximum and minimum temperatures of the entire period at the Lowland stations i s examined (Figs. 8,9  ), i t i s seen that maximum temperatures were below 19°C for  about 20% of the days under consideration.  In contrast, this temperature  group had a frequency of about 30% on the Plateau.  At Cheticamp and  Ingonish 35% and 40% of the total number of days had maximum temperatures above 25°C, whereas at station 01 on the Plateau these occurred with a frequency of 22%.  Plateau station 02 was more similar to the Lowland  stations i n this respect, having a frequency of 31%. Differences i n minimum temperatures between the two areas appear to be greater.  On the Plateau minimums were below 10°C on 29%  and 36% of the days measured, while at Cheticamp and Ingonish Beach only 19% and 14% of these days had temperatures below this level.  In addition,  minimums above 15°C occurred with frequencies of 50% and 44% at the two Lowland stations, compared with frequencies of 29% and 26% at Plateau stations 01 and 02. At Buchans, Newfoundland, maximum temperatures i n June, 1970 averaged 20.0°C (Table 5 ), varying l i t t l e from those for the Plateau. Minimum temperatures for this month at Buchans, however, averaged 7.7°C, and were 1° to 3° lower than mean minimums on the Plateau.  July and  Ton-jxvature  i  35  Classei  i i III iv v vi vii VIII ix  x  x:  I  xn  II  Temperature Classes  Dl IV V VI VII VIII IX. X XI  XII  -I  F i g u r e 8. % Frequency o f D a i l y Max/jaum and Ilinimun: Temperatures a t Cheticamp, N.'S. i n V a r i o u s  Classes  F i g u r e 9.  Z Frequency o f D a i l y Maximum and Minimum  Temperatures a t Ingonish Beach,N.S. i n Various  Classes  August means of both maximum and minimum temperatures  a t Buchans a l l  d i f f e r e d l e s s than 2° from means a t P l a t e a u s t a t i o n s . Graphs of the f r e q u e n c i e s w i t h which temperatures Buchans ( F i g . IO ) show t h a t maximum temperatures  Occurred  were below 19°C  of the days c o n s i d e r e d , about 5% fewer than on the P l a t e a u . temperatures two  areas.  i n the  were not below  10°C  more o f t e n than a t P l a t e a u s t a t i o n 01, but minimums were above 15°C 14% of the time, compared w i t h 29% and Mean temperature  ranges  26% a t P l a t e a u  only  stations.  f o r June a t Cheticamp and  Beach (Table 6 ) a r e s l i g h t l y lower  26%  Maximum  above 25°C o c c u r r e d w i t h about the same frequency In Newfoundland minimum temperatures  on  at  Ingonish  than those of the P l a t e a u s t a t i o n s .  J u l y and August means f o r Cheticamp a r e a l s o lower  than those of the  P l a t e a u , but means f o r I n g o n i s h Beach d u r i n g these months a r e equal to or h i g h e r than those of the P l a t e a u a r e a s .  Mean ranges  f o r a l l three  months a t Buchans are s l i g h t l y h i g h e r than those of the P l a t e a u . P r e c i p i t a t i o n a t I n g o n i s h Beach f o r the three-month p e r i o d resembled and  t h a t of the P l a t e a u i n both t o t a l amount r e c e i v e d (Table 7  in distribution  ( F i g . II  ).  R a i n f a l l a t Cheticamp was  d i s t r i b u t e d but t o t a l r a i n f a l l was  12 cm l e s s than t h a t of  similarly Ingonish  Beach, owing to the f a c t t h a t d u r i n g the week of August 6 to 13 camp r e c e i v e d much l e s s than d i d the o t h e r Cape Breton a r e a s . p r e c i p i t a t i o n a t Buchans, Newfoundland was Breton, but F i g u r e II  Wind and  ChetiTotal  s i m i l a r to t h a t of Cape  shows t h a t the d i s t r i b u t i o n was  uniform, w i t h more r a i n f a l l i n g  )  much more  i n J u l y at Buchans than a t o t h e r a r e a s .  r e l a t i v e humidity comparisons among the t h r e e areas  a r e not p o s s i b l e , s i n c e these are not measured a t the D.O.T. s t a t i o n s .  41  Temperature Classes I  II  III  IV  V  VI  VII  VIII  IX  X  XI  XII  30 H 25 A  20-  15-  Maximum V  10-  j -  u  c »N°5H 10  M inimum 15-  20-  25-  30-  I, Figure  10.  %  F r e q u e n c y - o f D a i l y Maximum a n d Minimum  Temperatures Various i  a t Buchans, Newfoundland i n  Classes.  Figure  II.  Weekly  Precipitation  i n Newfoundland  and  Totals  a t D.O.T.  Labrador.  Stations  43  I n summary, August areas  was  generally  a t Cheticamp  small,  and  Lowlands ground  and  however, c o u l d be  level  thus  accounted  but  than  Precipitation those  recorded At  lower two in  than  at  areas  differed  o n l y by  Although slightly that  cooler  than  the d i f f e r e n c e s  vegetation. on  the  The  vegetation the growing  than  season  and lowland  were  by  the  I t seems  temperatures  effect  of height  i n the above  1965).  of  the  the Plateau  summer, P l a t e a u  only.  were g e n e r a l l y  the  same on  the Plateau  as  stations.  Daily  June  temperatures those  temperature  for July  ranges  were and  slightly August  were g e n e r a l l y  d u r i n g June. . P r e c i p i t a t i o n  i n the  at  the  higher two  s m a l l amounts.  that  of  between  results  are  caused  i n J u n e w e r e h i g h e r on  summer c l i m a t e o f  the P l a t e a u f o r the  coastal  previously.  the  July  differences  trend of higher  the P l a t e a u , w h i l e  particularly  of  have been  mentioned  (Geiger,  Buchans, Newfoundland,  Newfoundland,  might  at Cheticamp  totals  that  Temperature  f o r the remainder  those  a r e a s were s i m i l a r .  than  for, since  ranges  the Lowland  t h o s e on  warmer  day  a continuous  temperature  were h i g h e r  one  location  consistent  i n the Lowlands,  ranges  degrees  f o r any  that  i s not  t h e P l a t e a u d u r i n g June,  Ingonish Beach.  i n instrument  Daily than  c l i m a t e of  several  differences  differences unlikely,  the  do  those  the Lowlands,  i t is difficult  the  are  two  suggest,  first  the P l a t e a u tends  few  areas  however,  i s several  weeks l a t e r  that  to  suggest affect  climatic conditions poorer  In o t h e r words, on  be  g r e a t enough to  w e e k s o f summer a r e  i n the Lowlands.  to  the P l a t e a u .  for the onset  of  44  IV. 1.  DESCRIPTIONS OF FOREST ASSOCIATIONS The Upland F i r  Dryopteris  spinulosa  (Abies  balsamea  - Hylocomium  -  umbratum)  Association (Table I , Appendix I ) This i s the most common of the three associations, forming the major part of the forest vegetation on the Plateau. well-drained s o i l s of low ridges.  I t i s found on  Maximum slope gradients i n these  areas are 4°, exposures are variable, and ground surfaces are characteristically hummocky, due to an abundance of decayed wood ).  (Fig.tr  The overstory vegetation of this association varies somewhat i n density.  The uppermost (A^) layer ranges i n coverage from 25% to 65%  and i s predominantly composed of  Abies  balsamea,  which has an average  coverage of 40.8%. The only other species found i n this layer i s glauca,  Picea  which occurred i n 30% of the stands studied, with an average  cover of only 4.3%.  The low tree layer (A^) varies i n coverage from 2%  to 52% and averages 34.6%. Only two species form this layer: balsamea,  again dominant, covering an average of 32.3%, and  Abies Betula  with an average coverage of 6.1%.  papyrifera,  I.  Shrub layers are sparsely developed i n the upland f i r association, i n many stands probably because of poor light conditions. The high shrub layer (B ), composed of  Abies  balsamea  transgressives,  .i  occurred i n only 70% of the stands, and has an average coverage of 2.5%.  45 a  F i g u r e 1Z .  The  upland  created height.  f i rassociation  by abundant (Photo  by  fallen Roy)  showing logs.  t h e hummocky The  stake  microrelief  i s 1 m.  in  45b  46  The low shrub l a y e r  decora,  balsamea  Betula  payrifera,  and Picea  constancy and  present i n a l l  Abies  t o t a l coverage. cover of 3.3%.  (B^) was  glauca  stands and averaged  6%.  dominates the l a y e r w i t h an average Amelanchiev  bartramiana,  Sorbus  a l s o occur i n t h i s l a y e r , but w i t h lower  abundance.  The herb and dwarf shrub (C) i s the b e s t developed v e g e t a t i o n l a y e r , having an average cover of 81.2%.  Development  of t h i s l a y e r i s  o f t e n v e r y i r r e g u l a r and appears to be determined i n p a r t by conditions.  F i g u r e s 13 and 14  development between the other  demonstrate these d i f f e r e n c e s i n  two a r e a s a d j a c e n t to each o t h e r , one shaded and  unshaded. Dryopteris  spinulosa  i s the dominant s p e c i e s of the C l a y e r  ( F i g . 15 ), and has an average coverage of 26.5%. an important subdominant, o c c u r r i n g i n a l l average coverage o f 19.8%. unshaded a r e a s , and may Abies  balsamea  Cornus  canadensis  respectively.  is  stands s t u d i e d w i t h an  T h i s s p e c i e s i s p a r t i c u l a r l y abundant i n  cover as much as 40% of the t o t a l stand  s e e d l i n g s and Oxalis  montana  are a l s o  area.  characteristic  members of the C l a y e r , h a v i n g average coverages of 12.5% and  17.8%  Seventeen other s p e c i e s which have c o n s t a n c y v a l u e s of  70% or more a r e found i n t h i s l a y e r ; of t h e s e , Coptis acuminatus,  light  Clintonia  borealis  coverages o f 5% o r more.  and Trientalis  borealis  trifolia,  Aster  have average  ),  Bryophytes and l i c h e n s growing on humus (Dh l a y e r ) a r e common i n the upland f i r  association.  55%, and v a r i e s from 20% to 90%.  T o t a l coverage of the l a y e r averages Development  of the l a y e r i s p r o b a b l y  c o n t r o l l e d m o s t l y by b o t h l i g h t and dense shading, i n some stands  47a  Figure 13.  The u n d e r s t o r y v e g e t a t i o n beneath  an unshaded a r e a  i n an upland f i r s t a n d , showing the r e l a t i v e  F i g u r e 1^ .  of Dryovier-is  spinulosa,  Cornus  ma.crovkyZ^.  (Photo by  Roy)  canadensis,  abundance and  SoZidago  A shaded a r e a o f the same stand as above, showing the r e l a t i v e s p a r s e n e s s o f the u n d e r s t o r y v e g e t a t i o n . EyZocomiviTi virbvatvm here.  (Photo by  i s the major b r y o p h y t e  Roy)  species  47b  48a  Figure 1 5 .  An upland f i r stand showing the abundance o f spinulosa. stands.  Shrub l a y e r s a r e n e a r l y absent (Photo by  Roy)  Dryopteris  i n these  48b  hindering bryophyte growth. The most common species of the Dh layer are umbratum  and  Pleurozium  Hylocomium  these intermingle to form large  schreberi;  discontinuous mats on humus hummocks.  H.  i s the more  umbratum  abundant of the two, having an average coverage of 29.0%, compared with 11.9% for  P.  In shallow depressions between the hummocks,  shreberi.  where runoff water may accumulate, small patches of often occur.  capillacewn  Sphagnum  This species was present i n 90% of the  stands, and has an average coverage of 12%.  Four additional, but less  abundant species occurring in this layer with high constancy are Dicranum  majus,  Polytrichum  Rhytidiadelphus  loreus,  Ptilium crista-castrensis,  and  commune.  Abundant windthrown and standing dead trees provide suitable microhabitats for a number of bryophytes and lichens (Ddw layer), whose total coverage varies from 4% to 20% and averages 10.5%.  Constant  species of this layer are:  trilobata,  Brachythecium  Dicranum  fuscescens,  s t a r k e i , Hypnum pallescens,  Plagiothecium  and several species of  A l e c t o r i a americana,  2.  The Black Spruce Pleurozium  schreberi)  Bazzania  (Picea  laetum,  Cladonia.  mariana  -  Association  (Table II , Appendix I ) The black spruce association most commonly occurs on the plateau as a band of vegetation i n low-lying and poorly-drained areas surrounding raised bogs.  The association may also be found i n erosion  trenches of peat bogs (Comeau, 1970) (Figure I  ) and, occasionally, on  50a  Figure 16 .  Open peat bogs on the Plateau around which the b l a c k spruce a s s o c i a t i o n commonly develops.  (Photo by B e i l )  Figure 17 . A black spruce stand showing wind-trimmed appearance of Picea 2.5 m. 3 m.  mariana  stems that grow above approximately  The t a l l e s t trees here are l i t t l e more than (Photo by Forwood)  50b  the  thin  rocky The  layers water  soils  soils  o f mixed  present  Picea mariana layers  shrub  layers,  of  55.2%  high,  of t h i s  P. mariana  41.4%  height  form to  this  Most  trees,  i n which the basal  a metre.  This  In  this  o p e n i n g s between  muoronata  and  occurring  with  constant  Abies  that  mariana  varies  of height,  included  Viburnum  a n d Kalmia  i n the  an a v e r a g e c o v e r a g e  3  m  stands;  those  ice blasting  a peculiar  growth  extend h o r i z o n t a l l y layering,  P. mariana  ( F i g . 18 ) .  and  cassinoides,  a  f o r up  vegetative  in this  association.  occur i n  Nemopanthus  abundant  8.5%  are  i n height.  snow a n d  a r e t h e most  of  these,  respectively.  Amelanchier  Other  bartramiana,  angustifolia.  c o v e r a g e o f t h e h e r b and  dwarf  shading  by  P. mariana  20%  to  68%,  i n coverage from  reproduction  the v a s c u l a r  of shrub s p e c i e s  thickets  canadense  flat.  two  have  p r o d u c e d by  a number  P. mariana  probably because of dense layer  be  Ground  Although densities  i n only  o f t h e stems  upper  The  i s greatest  have  pruned by  i s common among  association the  layer  a v e r a g e c o v e r a g e s o f 13.1%  species  Total  may  that  layer.  are severely  portion  is  seldom exceeding  of the  regardless  Rhododendron  balsamea,  growth,  deformity  form of r e p r o d u c t i o n  clumps  thick  B horizon.  in all  I t s development  i n t h e B^  shows p o o r  that  species  by  or l e s s .  and m i c r o r e l i e f  association.  as p a r t  ( F i g . 17 ) .  is level,  i s the dominant  and  coloured  a t d e p t h s o f one m e t e r  T r e e s were c l a s s e d reach  are characterized  by a r e d d i s h  where i t forms dense  i n t h e B^  do  areas  underlain  topography of these areas  plant  ridges.  i n low-lying  peat  i s usually  of low  i s dominant, w i t h  and  shrub l a y e r and  shrub  averages  (C) i s l o w , species.  48.4%.  an a v e r a g e c o v e r a g e o f  P. 9.1%,  The  52a  Figure \Z . A black, spruce stand showing the abundance of low shrubs i n openings between dense growths of Picea Shrub species seen here are Viburnum Ledum groenlandicum,  by Roy)  and Rhodendron  mariana.  cassinoides. canadense.  . (Photo  52b  f o l l o w e d by Rhododendron canadensis, trifolia,  Vaccinium Gaultheria  canadense  w i t h an average o f 8.3%.  angustifolium,  C\intonia  hispidula,  borealis,  and Nemopanthus  angustifolia,  Taxus  canadensis,  coverages but occur l e s s  and Ledum  Coptis  mucronata  s p e c i e s w i t h average coverages o f 3.0% o r g r e a t e r .  Cornus  are constant  Kalmia  groenlandicum  have s i m i l a r  frequently.  Bryophytes and l i c h e n s o f t h e Dh l a y e r a r e abundant here r a n g i n g i n t o t a l coverage from 65% to 95%, and a v e r a g i n g 76.3%. Pleurozium  schreberi  and Sphagnum  capillaceum  a r e t h e dominant  species,  o c c u r r i n g w i t h average coverages o f 27.8% and 25.3% r e s p e c t i v e l y , and are accompanied  by l e s s abundant s p e c i e s such as Bazzania  Dicranum  Hylocomium  majus,  splendens,  trilobata,  and s e v e r a l Cladonia  species.  Only two c o n s t a n t s p e c i e s a r e found i n t h e Ddw l a y e r o f t h i s association.  These a r e P t i l i d i u m c i l i a r e  has an average coverage of about may  2%.  and Dicranum  fuscescens;  The poor development  each  o f the l a y e r  be due to a l a c k o f both l i g h t and decayed wood i n t h e dense s t a n d s .  3.  The Swamp F i r (Abies  Osmunda cinnamomea Association  balsamea  - Sphagnum  -  capillaceum)  ( T a b l e HI , Appendix ] )  The swamp f i r a s s o c i a t i o n i s r a r e on t h e Cape B r e t o n P l a t e a u ; stands a r e s m a l l and a r e found o n l y on c e r t a i n l o w - l y i n g s i t e s a t t h e bases o f seepage s l o p e s and a l o n g streams, where ground water i s abundant and near t h e s u r f a c e f o r most o f the y e a r . these areas i s l e v e l , and the m i c r o r e l i e f  i s flat.  The topography o f These  sites are  more p r o t e c t e d than a r e those o f t h e b l a c k spruce a s s o c i a t i o n .  54  The  s o i l s i n t h e s e a r e a s have t h i c k o r g a n i c l a y e r s u n d e r l a i n  by Ae and B h o r i z o n s . The t a l l  t r e e l a y e r i s n o t as w e l l developed i n t h e swamp f i r  a s s o c i a t i o n as i n t h e upland f i r a s s o c i a t i o n ; i n t h e swamp f i r a s s o c i a t i o n t h e A^ o n l y averages averages Abies  The A^,, however,  38.9% and i s s i m i l a r t o t h a t of t h e upland f i r a s s o c i a t i o n .  balsamea  i s the,dominant  s t a n d s , w i t h an average  s p e c i e s i n b o t h l a y e r s o f swamp f i r  coverage o f 19.2% i n t h e A^ l a y e r , and 34% i n  F r e q u e n t l y Picea  the A^.  17.4% i n coverage.  glauca  i s p r e s e n t as w e l l ;  i t was found i n t h e  A^ l a y e r i n 57% o f t h e stands examined b u t has an average o n l y 3%.  coverage o f  I t o c c u r s i n t h e A^ w i t h a c o n s t a n c y o f 71%, and an average  coverage o f 8%. The p o o r e r development o f t h e A^ l a y e r . i n swamp f i r stands results i n better light fir  stands.  c o n d i t i o n s a t u n d e r s t o r y l e v e l s than i n upland  T h i s , together with the higher s o i l moisture, allows a  g r e a t e r development o f t h e shrub l a y e r s 'in t h e swamp f i r a s s o c i a t i o n . The h i g h shrub l a y e r average rugosa  ( B ^ ) , composed m a i n l y o f Abies  coverage o f 13%.  In 43% o f t h e s t a n d s , Picea  has an  mariana  and Alnus  were a l s o p r e s e n t i n t h i s l a y e r , but were not abundant.  shrub l a y e r i s b e t t e r developed It  balsamea,  and has an average  The low  coverage of 40.4%.  i s composed o f seven s p e c i e s w i t h constancy v a l u e s o f 70% o r more.  The most abundant o f these i s Abies  balsamea,  coverage o f 19.6%, f o l l o w e d by Alnus c o n d i t i o n s , w i t h an average o f 19.0%.  rugosa,  Picea  glauca,  Nemopanthus  an i n d i c a t o r o f wet s o i l  Other c o n s t a n t ' s p e c i e s i n  d e c r e a s i n g o r d e r o f abundance a r e Amelanchier decora,  o c c u r r i n g w i t h an average  mucronata,  ba/rtrajniano,, and Betula  Serous papyrifera.  55  The h i g h l i g h t and m o i s t u r e c o n d i t i o n s a l s o f a v o u r the development  o f a dense herb and dwarf  shrub l a y e r , which i n t h i s  a s s o c i a t i o n averages 92% i n coverage. l a y e r i s Osmunda cinnamomea  The most abundant  ( F i g . 19 ) .  species i n t h i s  The coverage of t h i s  Dryopteris  averages 42.5%, but on f a v o u r a b l e s i t e s may r e a c h 85%. spinulosa 11.5%.  species  o f t e n grows t o g e t h e r w i t h t h i s s p e c i e s , c o v e r i n g an average o f these Cornus  Beneath  canadensis  and Coptis  trifolia  o f t e n form  l a r g e p a t c h e s , w i t h mean coverages o f 14.0% and 12.5% r e s p e c t i v e l y . Abies  balsamea  s e e d l i n g s a r e a l s o common, c o v e r i n g an average of 11.8%.  Seventeen a d d i t i o n a l s p e c i e s w i t h c o n s t a n c y o f 70% or more compose the C l a y e r of t h i s a s s o c i a t i o n . acuminatus,  Aralia  Of t h e s e , Solidago  nudicaulis,  Oxalis  montana  macrophylla,  and Sorbus  Aster  decora  were  found i n a l l p l o t s and have average coverages g r e a t e r than 4%. Bryophytes and l i c h e n s of the Dh l a y e r form an average Sphagnum capillaceum  of 43.6% i n t h i s a s s o c i a t i o n .  and has an average coverage o f 27.9%. mium umbratum,  Pleurozium  i s usually schreberi  dominant,  and  Hyloco-  w i t h average coverages of 7.5% and 5.5% r e s p e c t i v e l y , a r e  common, p a r t i c u l a r l y on d r i e r s i t e s such as humus hummocks. trilobata,  coverage  Dicranum  majus,  c o n s t a n t but a r e l e s s  and Ptilium  crista-castrensis  Bazzania  are also  abundant.  The Ddw l a y e r averages 13.6% i n coverage, and i s composed o f n i n e s p e c i e s w i t h constancy vjalues g r e a t e r than 70%. d e c r e a s i n g o r d e r o f abundance: trilobata,  Ptilidium  Hypnum pallescens, s e v e r a l Cladonia  Rhytidiadelphus  ciliare,  Dicranum  fuscescens,  Tetraphis  geniculata,  Alectoria  species.  loreus,  These a r e , i n Bazzania  Plagiothecium americana,  laeturn, and  56a  Figure 19 . A stand of the swamp f i r association showing the abundance of  Osmunda  cinnamonea.  The tree strata of these stands  are r e l a t i v e l y open, allowing understory species to grow in abundance.  (Photo by Roy)  56b  57 4. Successional Communities (Table [V , Appendix I ) In a number of areas on the Plateau successional communities have developed following the disturbance of upland f i r stands. These 2 areas are relatively small, usually covering less than about 1000 m . In the areas examined, windfalls were not more abundant than those usually found i n undisturbed stands, and most of the trees present were standing dead.  This suggests that tree mortality was perhaps a result  of insect infestation or p a r t i a l wind damage that i n turn led to decay or infestation.  Although serious outbreaks of spruce budworm on the  Plateau have been reported (Recks, 1953), i t i s not known that these would result i n small, isolated areas of extensive damage as found i n the study area. No evidence of f i r e was found anywhere i n the study area. Three of these areas were examined.  The tree layers, where  present, were very reduced and were composed of Abies  balsamea.  In  plots 12 and 14 only A^ layers were present, with coverages of 7.5% and 25%, and plot 13, a l l that remained was an A^ layer with a coverage of 15%. Shrub layers were well developed i n a l l three areas, being composed of saplings that were released from the suppression of overstory shading after disturbance. In stands 12 and 13 the composed solely of Abies papyrifera  balsamea  layer was  (Fig. 2,0), whereas i n stand 14  was the dominant species and few A., balsamea  Betula  individuals  were present (Fig. 11 ). The B^ layer of the three stands had an average coverage of  58a  F i g u r e 2.0.  A successional saplings  a r e dominant.  destroyed by  F i g u r e 2,1  and  in The  some m a t u r e  A.  w h i c h Abies overstory  balsamea  balsamea i s not remain.  completely (Photo  Forwood)  A successional is  community  dominant.  dead.  community Most  (Photo by  i n which  of the mature  Forwood)  Betula trees  papvyvifeva seen here  are  58b  59 61.6%.  In stands 12 and 13 Betula  papyrifera  and Abies balsamea were  equally abundant i n this layer, while i n stand 14, Betula dominant. Rubus idaeus  was also present i n the B^; i t occurred with a  coverage of 7.5% i n stand 13 and 15% i n stands 12 and 14. decora,  Prunus  was  payrifera  pennsylvanica,and  Ribes  glandulosum  Sorbus  were also present  but less abundant i n two of the three stands. The C layer of the three stands was similar i n coverage to that of the upland f i r association, averaging 78.3%. Although i n the disturbed areas species d i v e r s i t i e s of the C layer were lower than those of the upland f i r stands, most of the species present i n the successional communities were also present i n upland f i r stands. The most abundant of these species i n the disturbed stands were Cornus canadensis,  Dryopteris  spinulosa,  had average coverages of about 11%. species included Oxalis Trientalis  borealis.  montana,  Other less abundant but constant  Aster  Rubus idaeus  and Abies balsamea', a l l  acuminatus,  and  Carex trisperma,  and Ribes glandulosum  were common i n  the disturbed areas, with average coverages of 8.3% and 7.5% respectively, but are not usually found i n undisturbed upland f i r stands.  These species appear to be suited to growing under the exposed  conditions of the disturbed areas, and successfully compete with the dense sapling growths.  Other species, such as Athyrium  Dryopteris  and Spreptopus  Phegopteris,  roseus,  Filix  -  femina,  may prefer the more  shaded conditions of undisturbed stands, where competition with saplings i s less intense.  5. The  Discussion  f o r e s t a s s o c i a t i o n s d e s c r i b e d above may be compared by  c o n s i d e r i n g t h e d i s t r i b u t i o n o f c o n s t a n t s p e c i e s ( o c c u r r i n g i n 70% o r more o f the stands s t u d i e d ) among them. l a y e r and arranged  These s p e c i e s a r e l i s t e d by  such t h a t groups by a s s o c i a t i o n form  (Table 9  ).  T o t a l numbers o f c o n s t a n t s p e c i e s a r e h i g h e s t i n t h e swamp f i r a s s o c i a t i o n , which has a t o t a l o f 40, a r e s l i g h t l y lower i n t h e upland fir  s t a n d s , t o t a l l i n g 34, and a r e lowest i n b l a c k spruce s t a n d s ,  t o t a l l i n g o n l y 28. The e x p l a n a t i o n f o r t h e r e l a t i v e l y h i g h number o f c o n s t a n t s p e c i e s i n swamp f i r stands i s perhaps  t h a t s i t e c o n d i t i o n s here a l l o w  the e s t a b l i s h m e n t o f s p e c i e s c h a r a c t e r i s t i c o f b l a c k spruce stands as w e l l as s p e c i e s c o n s t a n t i n upland  f i r stands.  In f a c t , most s p e c i e s  c o n s t a n t i n t h e swamp f i r a s s o c i a t i o n a r e a l s o c o n s t a n t members o f a t l e a s t one o f t h e o t h e r two a s s o c i a t i o n s .  The swamp f i r s i t e s must then  share p h y s i c a l c h a r a c t e r i s t i c s w i t h those o f b l a c k spruce stands and upland f i r s t a n d s . association.  Fewer s p e c i e s a r e c o n s t a n t i n t h e b l a c k spruce  A comparison  o f c o n s t a n t s p e c i e s by l a y e r f o r t h e t h r e e  a s s o c i a t i o n s i n d i c a t e s t h a t a l t h o u g h low shrub s p e c i e s a r e more numerous i n b l a c k spruce s t a n d s , herb, dwarf shrub, and bryophyte fewer  species are  i n t h e b l a c k spruce a s s o c i a t i o n than i n t h e o t h e r s .  whereas a  t o t a l o f 31 and 33 c o n s t a n t C and D l a y e r s p e c i e s a r e found (  i n the  upland f i r and swamp f i r a s s o c i a t i o n s , t h e b l a c k spruce a s s o c i a t i o n has o n l y 20. perhaps and  The e s t a b l i s h m e n t and growth o f herb and b r y o p h y t e  species i s  l i m i t e d i n b l a c k spruce stands because o f c o m p e t i t i o n f o r l i g h t  space w i t h dense growths o f shrubs and b l a c k spruce.  Table 9 .  . Distribution of Constant Species among Forest Associations  Upland F i r Association  Swamp F i r Association  Black Spruce Association  A^ layer Abies balsamea  100  (40.8)  100  (32.3)  a  86  (19.2)  100  (34.2)  A„ layer Abies balsamea  •k  Betula papyrifera  70  ( 6.1)  Picea glauca  71 (8.5)  layer Abies balsamea  70  (2.5)  100  (13.2)*  Picea mariana  71 (3.5) 100  (52.8)  B£ layer Kalmia angustifolia  .86 (4.0)  Picea mariana  •  100  (41.4)*  Viburnum cassinoides  100 (6.6)  Rhododendron canadense  100 (8.5)  * k  Nemopanthus mucronata Amelanchier bartramiana Abies balsamea  95  (3.4)  Betula papyrifera  70  (4.0)  Sorbus decora Alnus rugosa  86  (2.8)  100  100  (7.4)  100 (5.6)  100  (19.6)  100 (4.5)  *  71 (2.0) 100 (3.6) 71  •k  (14.0)  (13.1)  ON  Picea glauca  C layer Dryopteris Phegopteris Athyrium Filix-femina Osmunda claytoniana Moneses uniflora Acer spicatum  100 95 85 80 70  Betula papyrifera  95  Streptopus roseus  95  71  (2.9)  71  (1.9) (2.4)  *  (3.8) (4.2)*. A  (2.6) A (1.6) A (2.1) A (4.4) A  (1.9) (5.1)* (5.3) .  100 100 100  Trientalis borealis  100  Solidago macrophylla  90  Sorbus decora  90  Aster acuminatus  85  (2.1) (9.2)  Aralia nudicaulis  85  (4.7)  100  (26.5)* (17.8)*  100  86  Dryopteris spinulosa Oxalis montana  100  Cornus canadensis Abies balsamea  100 100  Coptis t r i f o l i a Clintonia borealis  100 100  Maianthemum canadense  100  (5.8) (4.3)*  95  (2.0)  100  (19.8)*  100 100  A  (7.9) A (4.8) A (8.7) (5.4) (11.5) (4.6)  100  (11.8)  100 86  100 100  (12.5) (3.9)  100 100  (3.9) (4.5)  100  (3.6)  71  (2.1)  100  (2.0)  100  (2.1)  Osmunda cinnamomea  100 100  (2.6)  Gaultheria hispidula .  100  (42.5) (2.3)  100  Vaccinium angustifolium  (3.1)  86  (1.8)  100  (6.4)  Amelanchier bartramiana Picea glauca  A  (12.5) (8.0) A  (14.6) A  (6.4) (2.0)  A  A A A  Viburnum cassinoides Taxus canadensis Carex trisperma Linnaea borealis  100  (2.6)  71 ((1.1) 86 (4.5)  71  (4.1)  71  (2.9)  71  (3.0) '  100  Ledum groenlandicum Rhododendron canadense Rub us Chamaemorus Picea mariana Kalmia angustifolia Epigaea repens D layer Tetraphis geniculata Sphagnum magellanicum  71  Rhytidiadelphus loreus Bazzania trilobata  90 (1.8) 80 (2.4)  Hypnum palbescens  75 (2.0) (29.0)  (1.6)"  71  (2.1)*  86  (2.0)  71  A  100  71  100 A  100 100  !  (4.9)'  100  A  Hylocomium umbratum  71 (2.9)  (1.9) (1.6) (4.9) (1.4)  *  (8.3)  :  (2.2)'  100  (9.1)  86  (7.9)  86  (2.7)'  100  (10.3)  ;  1  Alectoria americana  85 (1.8)  100  P t i l i u m crista-castrensis  80 (1.8)  100  (1.8)  100  (27.8)  100  (7.5)  100  (3.9)*  100  (25.3)  100  (1.7)*  100  (2.0)*  Pleurozium schreberi  100  (11.9)  A  Dicranum majus  95 (5.0)  100  (2.4)  Sphagnum capillaceum  90  100  (27.9)  Cladonia spp.  95 (1.3)  100  Dicranum fuscescens  70 (2.1)  (1.4) (1.7)  (12.1)  ;  86 (4.1)  Plagiothecium laetum  70  (2.0)  Polytrichum commune  75  (2.1)  Brachythecium  75  (1.9)  curtum  86  100  Ptilidium c i l i a r e  (1.7)"  (1.9)  '  100  (2.1)*  100  (5.9)*  A l e c t o r i a orchroleuca Polytrichum juniperinum  "' >  Hylocomium splendens  The f i r s t value i s Constancy (%) and the second i s Average Coverage Values marked with an  *  (%)  denote associations i n which a species i s most constant and abundant  65 A number o f t h e s p e c i e s distribution, include  being  constant  Coptis  bartramiana  trifolia  Maianthemum Clintonia  These several  studied.  These  reasons.  T h e y may  species, being  habitats  and  they  have  which are f a i r l y associations  canadense  be  association;  fuscescens canadensis  i n a l l three  be more t o l e r a n t t h a n  able  associations for  some o f t h e  to occupy a wider d i v e r s i t y other  species.  of  On  other micro-  the  other  t o l e r a n c e r a n g e s b u t demand  common i n a l l t h r e e  species i n one  are constant  particular  of the s i t e s  on w h i c h  these  conditions  the  a s s o c i a t i o n , o r a r e much i n others.  of c e r t a i n  site  These  are  i n some  c o n d i t i o n s found  in  two a s s o c i a t i o n s . are limited  include  as  Dryopteris  Moneses uniflora  apparently'grow w e l l  on  f i r stands,  one  f o r a n a s s o c i a t i o n , and  i n d i c a t e the e x i s t e n c e  species  i n only  a s s o c i a t i o n than  Osmunda claytoniana,  upland  Dicranum  constant  r a t h e r narrow  of the other Five  majus  Cornus  as d i s t i n g u i s h i n g s p e c i e s  i n s t a n c e s may  schreberi  develop.  Other more a b u n d a n t  Pleurozium Dicranum  s u c c e s s f u l l y compete w i t h  may  crista-castrensis  capillaceum  s p e c i e s may  constant  by  types  Ptilium  borealis  Sphagnum  neither  are widespread i n  i n a l lvegetation  balsamea  Amelanchier  useful  9  the f o l l o w i n g :  Abies  hand,  i n Table  the Plateau  and  constant  species  Phegopteris, and only  Acer on  to the upland f i r  Athyrium spicatum.  the c e r t a i n  are unable to t o l e r a t e  certain  Pilix-femina, These  sites  species  occupied  conditions i n  66 other  vegetation  requirements,  Dryopteris  Without a knowledge  however,  unfavourable. associations,  types.  Five  i ti sdifficult  other  species  Oxalis  to pinpoint  are frequently  b u t a r e more a b u n d a n t  spinulosa,  of the i n d i v i d u a l  i n upland  montana,  species'  which c o n d i t i o n s a r e  found i n other  f i r stands.  These a r e :  Cornus canadensis  a n d Hylocomium  only  f i r association.  umbratum. Several These  include  magellanicum, require the  species a r e constant  Alnus  rugosa, Tetraphis  and  conditions. factors  drained  sites  combined  such as  Picea  o f upland  i n abundance  with spruce  f i rstands,  stands  surround.  typically  angustifolia, schreberi abundant  also  have  light  canadense,  commonly o c c u r s i n black  spruce  Additional  prefer from  i s distinguished species,  species  splendens, i n other  growth  the betteroccupying  conditions.  Ledum groenlandicum,  Hylocomium  characteristics,  the species'  most  (Comeau, 1 9 7 1 ) w h i c h  These  may  light  these  but a r e prevented  by t h e c o n s t a n c y o f s e v e r a l bog communities  species  favourable  may a c t u a l l y  spruce a s s o c i a t i o n  common i n r a i s e d  Rhododendron  sites  glauca,  Sphagnum  of moisture characteristic of  relatively  because o f poor  The b l a c k  only  Some o f t h e s e  s u c h a s c o m p e t i t i o n may d i s c o u r a g e  Others,  associations  Osmunda cinnamomea,  geniculata.  Although black  there.  these  glauca,  t h e c o m b i n a t i o n o f an abundance  swamp f i r s o i l s  other  Picea  i n t h e swamp  are  Picea  from t h e other of which a r e also the black  mariana,  Rubus chamaemorus,  a n d Epigaea associations,  spruce  repens.  Kalmia  Pleurozium  b u t i s much more  stands.  groups a r e formed by s p e c i e s which a r e c o n s t a n t i n  two o f t h e t h r e e  associations,  or are constant  i n a l lbutare  67 particularly affinities  abundant  between  i n two t y p e s  the pairs  only.  These s p e c i e s  of associations  indicate  which share  them  i n this  way. Ten o f t h e s e a r e s h a r e d associations.  Solidago nudicaulis, loreus,  Sorbus  Dryopteris and Hypnum Several  roseus, Aster  Oxalis  f i r a n d swamp f i r  Trientalis  borealis,  acuminatus,  Aralia  montana,  Rhytidiadelphus  pallescens.  other  hispidula,  Taxus canadensis.  decora,  spiriulosa,  species are constant  swamp f i r a s s o c i a t i o n s .  Gaultheria  Streptopus  These a r e :  macrophylla,  by t h e upland  These  No b r y o p h y t e  i n t h e b l a c k s p r u c e and  Nemopanthus  include  Vaccinium  only  angustifolium, or l i c h e n  mucvonata,  Viburnum  species f a l l  cassinoides, into  and  this  category. i  The p r e v i o u s d i s c u s s i o n  association  shares  constant  spruce  associations,  upland  f i r association.  similarities of  these  whereas  also  constant  ranges.-  '  the upland  tree  layers  f i r and b l a c k  related  tothe  t o physiognomic  and p o o r l y developed  to the upland  i n both  t h e swamp f i r  f i r a n d swamp f i r a s s o c i a t i o n s .  spruce  a number o f c o n s t a n t  are constant  both  although  i t i s more c l o s e l y  the reverse i s true f o rblack shares  that  T h i s may i n p a r t b e r e l a t e d  t h e upland  i s much^less s i m i l a r  species  species with  floristically  have d e f i n i t e  association but  between  suggests  of these  stands.  species with  i n t h e swamp f i r a s s o c i a t i o n  those  layers,  The b l a c k  spruce  swamp f i r s t a n d s ,  f i r association. types;  shrub  Both  that  R e l a t i v e l y few a r e shared a r e  a n d may h a v e w i d e t o l e r a n c e  68 6.  Comparison of the P l a t e a u A s s o c i a t i o n s w i t h B o r e a l F o r e s t s i n E a s t e r n Canada  As p r e v i o u s l y mentioned i n the i n t r o d u c t i o n , some c o n t r o v e r s y e x i s t s over the q u e s t i o n of whether or not the P l a t e a u f o r e s t s  are  b o r e a l , and a comparison o f r e s u l t s from t h i s study w i t h those of n e i g h b o u r i n g b o r e a l r e g i o n s would be v a l u a b l e . an examination  The  f o l l o w i n g , then, i s  of f o r e s t v e g e t a t i o n s t u d i e s i n c e n t r a l Newfoundland  (Damman, 1964), s o u t h e a s t e r n Quebec ( L i n t e a u , 1955) ( W i l t o n , 1964), and  and  Labrador  a comparison of these w i t h the P l a t e a u a s s o c i a t i o n s .  Newfoundland C e n t r a l Newfoundland f o r e s t s dominated by Abies  balsamea  grouped by Damman (1964) i n t o the balsam f i r - w h i t e b i r c h  association.  F i v e s u b a s s o c i a t i o n s were r e c o g n i z e d i n t h i s a s s o c i a t i o n . Lycopodium  were  Of these  Dryopteris  -  the upland  f i r a s s o c i a t i o n of Cape Breton than are the o t h e r  balsam f i r i s s e l e c t e d as b e i n g more s i m i l a r  l a y e r dominated by Dryopteris The  Dryopteris  composition. papyrifera  -  and Picea  f i r a s s o c i a t i o n and  balsam f i r f o r e s t are s i m i l a r  In both types, Abies glauca  a  spinulosa.  t r e e l a y e r s of the upland  - Lycopodium  to  sub-  a s s o c i a t i o n s , s i n c e i t o c c u r s on a p p a r e n t l y s i m i l a r s o i l s and has herb  the  balsamea  the  i n species  i s dominant, w h i l e  occur i n s m a l l numbers.  Tree  Betula  layer  I:  coverages  are a l s o s i m i l a r in, the two  t r e e s tend t o be s e v e r a l metres t a l l e r  types, a l t h o u g h the Newfoundland than those on the P l a t e a u .  Newfoundland and Cape B r e t o n stands have p o o r l y developed a l t h o u g h A.  balsamea  and B.  papyrifera  shrub  Both  layers,  s a p l i n g s are more f r e q u e n t i n  69  the Cape Breton association. The herb layer of the Newfoundland forest type i s more poorly developed than that of the upland f i r association, having a maximum coverage of 65%, compared with an average of 81.2% i n the Cape Breton association, while moss layer coverages are similar i n both areas. Both the herb and moss layers of the Newfoundland subassociation are f l o r i s t i c a l l y poorer than those of the upland f i r association. upland f i r association has a t o t a l of 34 constant species. not  The  Damman did  calculate constancy, thus those species occurring i n two of the  three stands of h i s subassociation are here considered of equal value to the constant species of Cape Breton associations f o r the purposes of type characterization.  These t o t a l 18 i n number, of which 12 are also  constant i n the upland f i r association. Abies Acer  balsamea  Hylocomium  spicatum  Betula  They are as follows: umbratum  Maianthemum  papyrifera  Moneses  canadense uniflora  Cornus canadensis  Pleurozium  schreberi  Dryopteris  Ptilium  crista-castrensis  spinulosa  Several others are constant i n the Newfoundland type, but are uncommon or absent i n the Cape Breton association. salebrosun,  Hylocomium  Streptopus  splendens,  amplexifolius,  These are  Lycopodium  and/, Viola  Brachythecium  annotinum,  Picea  glauca,  incognita.  Five of the remaining 26 species constant i n Cape Breton commonly occur i n other subassociations of the Newfoundland balsam f i r white b i r c h association. groenlandica  (C. trifolia)  3  These are: Bazzania Clintonia  borealis,  trilobata, Dicranum  Coptis majus,  and  70 Polytrichum  commune. In a d d i t i o n t e n o t h e r s p e c i e s a r e p r e s e n t , a l t h o u g h non-constant,  i n t h e balsam f i r w h i t e b i r c h a s s o c i a t i o n . Amelanchier Aralia  bartramiana  nudicaulis  They i n c l u d e :  Dryopteris  phegopteris  Rhytidiadelphus  toreus  Athyrium.  Filix-femina  Solidago  macrophylla  Cladonia  spp.  Sphagnum  capillacewn  Dicranum  fuscescens  Streptopus  roseus  Thus, o f t h e 34 s p e c i e s c o n s t a n t i n t h e Cape B r e t o n upland f i r a s s o c i a t i o n , 27 a r e p r e s e n t i n t h e Newfoundland balsam f i r w h i t e b i r t h association.  Only 17 o f t h e s e , however, a r e common i n any o f t h e sub-  a s s o c i a t i o n s , and o n l y 12 a r e common i n the s u b a s s o c i a t i o n w h i c h most resembles  the upland f i r type.  A l t h o u g h Damman may have d e f i n e d h i s  a s s o c i a t i o n s and s u b a s s o c i a t i o n s more n a r r o w l y than those o f t h i s s t u d y , the Cape B r e t o n a s s o c i a t i o n g e n e r a l l y appears t o be r i c h e r i n b o t h number o f s p e c i e s and s p e c i e s ' abundance than t h e Newfoundland association.  Many o f t h e Cape B r e t o n s p e c i e s which a r e p r e s e n t b u t  uncommon i n Newfoundland, may i n Newfoundland be a t o r near t h e n o r t h e r n l i m i t o f t h e i r geographic  range.  B l a c k spruce f o r e s t s i n Newfoundland were grouped i n t o two a s s o c i a t i o n s , t h e Kalmia Forests.  The Kalmia  - C o n i f e r F o r e s t s , and t h e B l a c k Spruce Moss  - C o n i f e r F o r e s t s o c c u r on poor s o i l s , some o f  w h i c h a r e p o o r l y - d r a i n e d , and l i k e t h e b l a c k s p r u c e f o r e s t s i n Cape B r e t o n , have a w e l l - d e v e l o p e d shrub l a y e r i n w h i c h Kalmia i s abundant.  angustifolia  The B l a c k Spruce-Moss F o r e s t s , on t h e o t h e r hand, a r e  m o s t l y o f f i r e o r i g i n , occur on u p l a n d s i t e s o r i g i n a l l y o c c u p i e d by  71  Abies  balsamea  f o r e s t s , and have v e r y s p a r s e shrub l a y e r s .  reasons the Kalmia  For these  - C o n i f e r F o r e s t s a r e c o n s i d e r e d more s i m i l a r to the  Cape Breton b l a c k spruce a s s o c i a t i o n , and the f o l l o w i n g comparisons are  made w i t h t h a t type. The Kalmia  subassociations. appears  - C o n i f e r type was f u r t h e r s u b d i v i d e d i n t o t h r e e Of these, t h e Sphagnum - Kalmia  subassociation  to be most s i m i l a r to the Cape B r e t o n a s s o c i a t i o n , and i s  s e l e c t e d f o r comparison. The stands o f the Newfoundland f o r e s t s t r u c t u r a l l y from those on the P l a t e a u .  type  differ  While the t r e e s o f the  P l a t e a u stands a r e v e r y dense and s h r u b - l i k e i n n a t u r e , w i t h few exceeding 3.5 m i n h e i g h t , those i n Newfoundland form a d e f i n i t e l a y e r t h a t appears  to be l e s s dense and ranges  (7.5 m) t o 33 f t (9.9 m).  tree  i n h e i g h t from 25 f t  T h i s suggests t h a t h a b i t a t c o n d i t i o n s on t h e  Newfoundland s i t e s a r e g e n e r a l l y more f a v o u r a b l e f o r t r e e growth. Floristically,  the b l a c k spruce a s s o c i a t i o n i n Cape Breton i s  r i c h e r than the Sphagnum-Kalmia-black  spruce f o r e s t s i n Newfoundland.  27 s p e c i e s a r e c o n s t a n t i n the Cape B r e t o n f o r e s t are  c o n s t a n t i n the Newfoundland type.  type, w h i l e o n l y 15  Most o f the s p e c i e s c o n s t a n t  i n Newfoundland however, a r e a l s o c o n s t a n t i n Cape B r e t o n .  These  include: Abies  balsamea\..  Bazzania  trilobata  Kalmia Picea  angustifolia mariana  Cladonia  spp.  Pleurozium  schreberi  Cornus  canadensis  Sphagnum  capillaceum  Gaultheria Hylocomium  hispidula umbratum  Vaccinium  angustifolium  Ptilium  crista-castrensis  72 The  remaining  three  species  idaea,  dicranum  absent  i n Cape B r e t o n ;  scopavium,  Several  Sphagnum-Kalmia found  Other  as  species  These  are are,  also  groenlandica  summary,  then,  fairly  although  black  by  Abies  similar  ciliare.  Conifer  Forest  association  subassociation t h e two t y p e s  repens  Maianthemum  canadense  Nemopanthus  mu.cronata  trifolia). Viburnum  cassinoides  about h a l f o f t h e s p e c i e s  constant  Forest,  a l l but three  of the species The f o r e s t  a r e present i n  constant types  i n Newfoundland  o f t h e two  areas  floristically. only  balsamea  -  Although  these a r e  a s s o c i a t i o n a r e common i n t h e  i n Cape B r e t o n .  swamp- f i r " a s s o c i a t i o n " i n forest  (C.  only  spruce  - Conifer  Damman d e s c r i b e d dominated  -  Epigaea  fuscescens  and i n t u r n most  constant  forests,  a n d Ptilidium  Kalmia  borealis  Dicranum  Newfoundland,  i n the  spruce  frequently-  i n none o f t h e Newfoundland s u b -  trisperma  Coptis  Kalmia  In the black  bartramiana  Clintonia  Newfoundland  a r e uncommon i n t h e  include:  ' . Carex  t h e Cape B r e t o n  , are infrequent or  i n Newfoundland., b u t a r e m o r e  are constant  Amelanchier  in  species  Ledum groenlandicum  but are present  a whole.  In  Plateau  subassociations.  canadense,  associations,  undulatum  vitis-  -  Cape B r e t o n  Cape B r e t o n  Vacciniwn  i n Newfoundland,  Dicranum  and  subassociation  i n other  Rhododendron  constant  one f o r e s t  and o c c u r s  Cape-Breton.  type  on- s i t e s  i n Newfoundland similar  Th±s~±s-• the-Garex'  that i s  to those  -  o f the. •  balsam f i r ' •  of the balsam f i r - w h i t e b i r c h a s s o c i a t i o n . do d e v e l o p  under  apparently.similar habitat  c o n d i t i o n s , o n l y a few o f t h e s p e c i e s which i n Cape B r e t o n the swamp f i r a s s o c i a t i o n from t h e upland These a r e Carex  Newfoundland t y p e . Linnaea  borealis,  cinnamomea, i s absent  and Taxus  t h e most abundant herb i n t h e Newfoundland  f i r t y p e were p r e s e n t i n t h e  trisperma,  canadensis.  distinguish  Gaultheria  hisvidula,  On t h e o t h e r hand, Osmunda  s p e c i e s of t h e swamp f i r a s s o c i a t i o n ,  forests.  Quebec Linteau  (1955) r e c o g n i z e d a number of broad  s o u t h e a s t e r n Quebec dominated by Abies  balsamea.  f o r e s t groups i n  Of t h e s e , o n l y the  Herb and F e r n F o r e s t s group has a w e l l - d e v e l o p e d herb l a y e r . the most s i m i l a r o f these t o t h e upland Breton Plateau.  f i r a s s o c i a t i o n on t h e Cape  T h i s group i s composed o f t h r e e cover t y p e s , based on  the s p e c i e s c o m p o s i t i o n o f t h e u n d e r s t o r y v e g e t a t i o n . Dryopteris-Oxalis  l a y e r i n which  i s r e l a t i v e l y abundant. . The Dryopteris-Oxalis  l i k e t h e upland from g l a c i a l As  dryopteris cover  f i r a s s o c i a t i o n , o c c u r s on w e l l - d r a i n e d s o i l s  type, developed  till. Dryopteris-  i n t h e upland f i r a s s o c i a t i o n , t r e e l a y e r s o f t h e  Oxalis  type, a r e composed l a r g e l y o f Abies  Betula  papyrifera  developed.  Of t h e s e , t h e  t y p e i s t h e most s i m i l a r t o t h e upland f i r  a s s o c i a t i o n on t h e P l a t e a u , h a v i n g a herb spinulosa.  I t i s thus  and Picea  glauca,  The herb and bryophyte  p o o r l y developed  balsamea  w i t h low d e n s i t i e s o f  and shrub l a y e r s a r e p o o r l y l a y e r s , however, a r e much m o r e  than those o f t h e Cape B r e t o n a s s o c i a t i o n . . Only 11  s p e c i e s occur i n t h e Quebec type w i t h a presence o f 2 0 % . o r m o r e . t h e s e , e i g h t a r e a l s o c o n s t a n t i n t h e upland f i r  association...  Of  These  are Abies  balsamea,  Clintonia  (Pleurozium  schreberi),  Maianthemum  canadense,  delicatulum  Calliergon  Cornus canadensis, Oxalis  remaining t h r e e , Dicranum Thuidium  borealis,  montana,  scoparium,  schreberi  Dryopteris  and Solidago  spinulosa, macrophylla.  Plagiothecium  denticulatum,  The and  were not found i n upland f i r s t a n d s .  E l e v e n other c o n s t a n t s p e c i e s of the upland f i r a s s o c i a t i o n are  present but l e s s common i n the Dryopteris-Oxalis  those above.  type than a r e  They a r e :  Amelanchier  bartramiana  Aralia  nudicaulis  Aster  acuminatus  Ptilium  crista-castrensis  Moneses Sorbus  Coptis groenlandica (C. trifolia)  uniflova decora  Sphagnum Streptopus  Dryopteris  capillaceum roseus  phegoptoris Trientalis  borealis  Thus, a t o t a l o f 14 c o n s t a n t s p e c i e s of the upland f i r association Oxalis  i n Cape B r e t o n , a r e absent from the Quebec  type, i n d i c a t i n g t h a t g e n e r a l l y  floristically  Dryopteris-  the Quebec f o r e s t s a r e  l e s s s i m i l a r to the Cape B r e t o n f o r e s t s than a r e those i n  Newfoundland. The b l a c k spruce a s s o c i a t i o n s i m i l a r to the Peat Moss and Dwarf occur on p o o r l y - d r a i n e d s o i l s Two  (  i n Cape Breton appears to be most  Shrub F o r e s t group i n Quebec.  and have a w e l l developed shrub l a y e r .  cover types a r e r e c o g n i z e d i n Quebec f o r t h i s group, of which the  Sphagnum-Rubus  type most resembles the Cape B r e t o n  The s o i l s of the Sphagnum-Rubus part  Both  association.  type a r e w a t e r - s a t u r a t e d f o r  of the y e a r , and have t h i c k humus l a y e r s , as do most of those  beneath b l a c k spruce stands i n Cape B r e t o n . stands, however,  U n l i k e the Cape Breton  t h e Quebec f o r e s t s have a f a i r l y w e l l developed t r e e  layer. The Sphagnum-Rubus  type, l i k e a l l o f the b o r e a l f o r e s t  d e s c r i b e d above, i s f l o r i s t i c a l l y association.  types  poorer than t h e Cape B r e t o n  Most o f t h e s p e c i e s common i n b l a c k spruce stands i n  Quebec a r e a l s o common i n Cape B r e t o n , but a l a r g e number of t h e cons t a n t Cape B r e t o n s p e c i e s a r e r e s t r i c t e d Quebec f o r e s t s . Sphagnum-Rubus  i n o c c u r r e n c e or absent i n the  Only 16 s p e c i e s a r e found i n 20% or more of t h e stands, t h i r t e e n of which a r e c o n s t a n t i n the Cape  B r e t o n a s s o c i a t i o n as w e l l .  Abies  These a r e :  balsamea  Ledum  Carex trisperma  Picea  Calliergon schreberi (Pleurozium schreberi)  Ptilium  Chiogenes (Gaultheria  hispidula hispidula)  Clintonia  borealis  Coptis Cornus Kalmia  groenlandica  (C.  Rubus  groenlandicum mariana crista-castrensis chamaemorus  \ccinium Vacciniwn (V.  trifolia)  canadensis angustifolia  The remaining t h r e e s p e c i e s common i n Quebec a r e :  (V. myrtilloides),  Smilacina  prifolia,  other Cape Breton s p e c i e s , Eylocomium bartramiana Quebec.  pennsyli pennsylvanicum angustifolium)  Vaccinium  and Sphagnum palustre. splendens  and  canadense  Two  Amelanchier  a r e p r e s e n t but uncommon i n the Sphagnum-Rubus  f o r e s t s of  ! The above 15 s p e c i e s which a r e p r e s e n t i n both Cape B r e t o n and  Quebec make up o n l y about 55% of t h e t o t a l c o n s t a n t i n t h e b l a c k spruce  association Quebec,  i n Cape B r e t o n .  are particularly  Nemopanthus  mucronatus,  frequent  Viburnum  Sphagnum capillaceum,  lying  i n Cape B r e t o n .  cassinoides,  types  appear  Abies  study  well-drained  sites.  range of s i t e s  canadense,  f o r southeastern  on t h e P l a t e a u .  by  Picea  i s restricted t h a t A.  It i s possible  i n Cape B r e t o n  Rhododendron  described  t o be o c c u p i e d  balsamea  These a r e :  ailiare.  t o t h e swamp f i r a s s o c i a t i o n  wet s i t e s  Linteau's  o f those which a r e not found i n  and Ptilidium  None o f t h e c o v e r correspond  Several  mariana  I n Quebec, l o w forests,  as a dominant balsamea  Quebec  and i n  t o more  occupies  a wider  t h a n i n Quebec.  Labrador Wilton which only as  tree  species.  As  the Labrador type  by  low d e n s i t i e s  of  river  i n both forest  i s composed  Picea types  types f o r Labrador o f  Herb  type,  i n distribution  glauca  Abies  balsamea  productive  forest  to certain  areas,  f i r association,  mostly of and  i s poorly  In Labrador these a r e  has  valleys.  i n t h e Cape B r e t o n u p l a n d  of  species.  Forest  I t i s o n e o f t h e most  i n L a b r a d o r , and i s r e s t r i c t e d  many o f w h i c h a r e f e r t i l e  layer  five  one, t h e F i r - S p r u c e - B i r c h / R i c h  t h e dominant  types  (1964) d e s c r i b e d  Betula  Abies  the tree  balsamea,  papyrifera.  accompanied The shrub  d e v e l o p e d , and i s composed  Sorbus  decora,  Acer  layer  spicatum,  o f few  Alnus  I,  crispa, are  also  Alnus  rugosa,  a n d Viburnum  common i n t h e u p l a n d Herb  apparently  well  o f w h i c h o n l y t h e f i r s t two  f i r association.  and b r y o p h y t e l a y e r s  less  edule,  i n the Labrador forests a r e  developed than a r e those  i n Cape B r e t o n .  In  77 Labrador,  these l a y e r s a r e composed o f o n l y 13 c h a r a c t e r i s t i c s p e c i e s ,  whereas a t o t a l of 31 a r e c o n s t a n t i n the upland Breton.  f i r a s s o c i a t i o n of Cape  E i g h t o f the s p e c i e s mentioned f o r Labrador  the Cape Breton a s s o c i a t i o n . Clintonia Cornus  Oxalis  canadensis spinulosa  Maianthemum Other Labrador  These a r e :  borealis  Dryopteris  repens,  splendens  were o c c a s i o n a l l y found  Climacium  dendroides  Spruce/Sphagnum Cape B r e t o n .  montana  Pleurozium  schreberi  Ptilium  crista-oastrensis  canadense  s p e c i e s , Goody era  forest  Listera  cordata,  and  i n the Cape Breton f o r e s t s ,  and Mnium ciliare  Of the Labrador  a r e a l s o common i n  Hylocomium while  were absent.  types dominated by Picea  mariana,  the  type i s most s i m i l a r t o the b l a c k spruce a s s o c i a t i o n i n Both f o r e s t groups occur i n p o o r l y d r a i n e d a r e a s , o f t e n  a l o n g the edges o f open bogs, and t r e e s p e c i e s c o m p o s i t i o n s a r e s i m i l a r . Trees i n the Labrador  type, however, a r e l a r g e r and more w i d e l y  spaced  than those on the P l a t e a u . W i l t o n ' s d e s c r i p t i o n o f the u n d e r s t o r y v e g e t a t i o n i n b l a c k spruce f o r e s t s i s b r i e f , but g e n e r a l l y suggests  t h a t i n the Labrador  f o r e s t s u n d e r s t o r y s p e c i e s a r e fewer than those i n Cape B r e t o n .  Only  seven s p e c i e s a r e mentioned f o r Labrador, whereas 20 a r e c o n s t a n t i n the Cape Breton b l a c k spruce / a s s o c i a t i o n .  Four o f the Labrador s p e c i e s ,  Ledum groenlandicum,  Rubus chamaemorus,  Pleurozium  schreberi,  Sphagnum spp. a r e a l s o common i n Cape B r e t o n . Chamaedaphhe calyculata,  Kalmia  polifolia,  f r e q u e n t l y occur i n the Cape Breton  and  The remaining s p e c i e s ,  and Equisetum  association.  arvense  do not  78  The of  above d i s c u s s i o n  the selected  Cape B r e t o n total  Plateau.  forest  Since  number o f c o n s t a n t  associations, This  Labrador  designed fairly  common  are also  of forest  Labrador  indicate  balsamea  and  similar  sites  stands  types  common  and  mariana  are very  forest  forest  that  These  Plateau  areas,  a number o f  associations  i n Quebec,  the tree  on t h e  Newfoundland, and  Although  growth o f  i n Cape B r e t o n species  than on  layers  of the species  but generally  Abies  composition of  T h e h e r b and b r y o p h y t e  c o n t a i n most  types,  floristically.  of the  d e s c r i b e d as  have an a d d i t i o n a l  i n Quebec,  Newfoundland,  include:  bartramiana  Aralia  nudicaulis  Aster  acuminatus  Athyrium  Filix-ffemina  Brachythecium Dicranum  Hulten  forest  a r e uncommon o r a b s e n t  Amelanchier  '  percentage of the  ignored.  types  similar.  associations  i n the other  Labrador.  three  i n those of the  i n Labrador,  appears t o be poorer  i n the other  number o f s p e c i e s  forest  species  y e t b e c a u s e h i s s t u d y was  a number o f s i m i l a r i t i e s .  Pieea  compared  Cape B r e t o n  boreal  common  a small  descriptions,  s p e c i e s may h a v e b e e n  and s e l e c t e d  o f t h e common  a r e p e r h a p s much r i c h e r  The a b o v e c o m p a r i s o n s b e t w e e n Plateau  most  i n t h e Cape B r e t o n  forests  survey  that  these represent  by W i l t o n ' s  as a broad  types  species  the Plateau  i s indicated  indicates  Dryopteris  (1964) i n d i c a t e d  curtum  majus  phegopteris  Nemopanthus  mucronata  Osmunda  claytoniana  Osmunda cinnamomea Rhytidiadelphus Sphagnum  phegopteris that  Dryopteris  Streptopus  Athyrium-Filix-femina,  loreus  capillaceum roseus Osmunda cinnamomea,  and  Osmunda claytoniana  have o n l y s c a t t e r e d d i s t r i b u t i o n i n n o r t h e r n  Canada, and L a R o i (1967) found them i n o n l y a few b o r e a l f o r e s t Streptopus  roseus  in boreal forests,  and Aralia,  however, a r e f a i r l y widespread  (LaRoi, 1967) i n s p i t e of the f a c t  i n f r e q u e n t i n Newfoundland I t appears, then, resembling  nudicaulis,  that b o r e a l f o r e s t types  c e n t r a l Newfoundland, s o u t h e a s t e r n  For these reasons,  Rowe (1959, 1972).  structurally,  f o r e s t a s s o c i a t i o n s a r e found i n  Quebec, and p a r t s o f Labrador.  m a j o r i t y o f s p e c i e s c h a r a c t e r i s t i c of these  should be c o n s i d e r e d  t h a t they were  (Damman, 1964) and Quebec ( L i n t e a u , 1955).  the two most common P l a t e a u  the P l a t e a u .  stands.  types a r e a l s o common on  the f o r e s t s of the Cape Breton  Plateau  p a r t of the B o r e a l F o r e s t Region d e s c r i b e d by The comparative r i c h n e s s of the u n d e r s t o r y  v e g e t a t i o n o f the Cape Breton  f o r e s t s , both i n numbers o f s p e c i e s and  i n s p e c i e s ' abundance, however, suggests t h a t they be c l a s s e d as a distinct  The  s e c t i o n w i t h i n t h i s Region.  I,  80  V.  General  FOREST SOILS  c h a r a c t e r i s t i c s of s o i l p r o f i l e s examined on  Plateau  suggest the e x i s t e n c e of f o u r s o i l t y p e s .  drained  s o i l s beneath upland  swamp f i r stands,  poorly drained  l o w - l y i n g a r e a s , and  valid  1.  L-F-H  These  particularly in Nevertheless,  r e l a t i n g them to v e g e t a t i o n .  Morphological C h a r a c t e r i s t i c s f i r stands  above the parent  have p r o f i l e s c o n s i s t i n g of  m a t e r i a l or C h o r i z o n :  h o r i z o n , a leached Ae h o r i z o n , and  Horizons  in  f o r the purposes of g e n e r a l l y d e s c r i b i n g the  S o i l s beneath upland  (Fig. 2 2 ) .  stands  on r i d g e s .  a f a i r amount of v a r i a b i l i t y ,  f o r e s t s o i l s of the P l a t e a u and  L-F-H  stands  well-  s o i l s under  s o i l s below b l a c k spruce  c h a r a c t e r i s t i c s , i s found i n each.  these a r e c o n s i d e r e d  three horizons  poorly drained  s o i l s of b l a c k spruce  groups are broad, and terms of c h e m i c a l  f i r stands,  These a r e :  the  an i l l u v i a t e d  an  organic  B horizon  A composite d e s c r i p t i o n of these p r o f i l e s i s as f o l l o w s :  Mean Depth (cm) 10.3  - 0  Description  c o n i f e r needles and herbaceous l i t t e r u n d e r l a i n by v e r y dark brown (10YR2/2, I; dry and wet) f i b r o u s mor humus; white f u n g a l hyphae present;^abundant c o a r s e , medium, and f i n e r o o t s ; boundary smooth and abrupt; h o r i z o n t h i c k n e s s 6.3 cm to 15.2 cm; pH 3.4-4.6. 1  S i z e and abundance c l a s s e s f o r r o o t s are as d e s c r i b e d i n Table I , Appendix II . 0  81a  Figure 22.  A s o i l p r o f i l e i n an upland f i r stand. The Ae horizon here i s very thin and gravel sized fragments are common i n the lower horizons. Few roots are found below the upper B horizon. ( Photo by Roy  )  82 Description  Horizons  Mean Depth (cm)  Ae ( A e j )  0 - 10.6  gray (10YR 5/1, d r y ) to v e r y d a r k gray (10YR 3/1, m o i s t ) s i l t y loam to sandy loam; p l e n t i f u l medium and f i n e r o o t s ; g r a n u l a r s t r u c t u r e ; abrupt and smooth t o wavy boundary; h o r i z o n t h i c k n e s s 1.3 cm to 25.4 cm; pH 4.2 to 5.2.  10.6-37.9  y e l l o w i s h r e d (5YR 4/6, d r y ) t o dark r e d d i s h brown (5YR 3/2, m o i s t ) ^ s i l t y loam to sandy loam; 5 to 25% g r a v e l ; compacted; few to v e r y few medium and f i n e r o o t s ; average maximum r o o t i n g depth 34.2 cm; g r a n u l a r s t r u c t u r e ; compacted; boundary g r a d u a l and i r r e g u l a r ; h o r i z o n t h i c k n e s s 6.8 cm t o 12.8 cm; pH 4.5 to 5.7.  37.9  +  l i g h t y e l l o w i s h brown (10YR 6/4, d r y ) to dark brown (7.5 YR 4/4, m o i s t ) loam t o sandy loam; 5% to 25% g r a v e l and c o b b l e s ; compacted; g r a n u l a r s t r u c t u r e ; r o o t s absent; pH 5.0 to 5.9.  Swamp f i r stands a r e developed on s o i l s c h a r a c t e r i z e d by the presence of a v e r y t h i c k , w a t e r - s a t u r a t e d L-F-H h o r i z o n . are  w e l l developed Ae and B h o r i z o n s  common i n these s o i l s , and Ae h o r i z o n s .  (Fig. 2 3 ) .  Beneath t h i s  Groundwater seepage i s  p a r t i c u l a r l y a t the boundary between  P r o f i l e c h a r a c t e r i s t i c s a r e summarized  t h e L-F-H  as f o l l o w s :  Description  Horizons  Mean Depth (cm)  L-F-H  35.9-0  b l a c k mixed peat; abundant c o a r s e , medium and f i n e r o o t s ; boundary abrupt and smooth; I h o r i z o n t h i c k n e s s 18.0 cm t o 60.9 cm; i'pH 4.0 to 4.7.  Ae  0-14.2  gray (10YR 6/1 d r y , 10YR 5/1, m o i s t ) s i l t y loam t o sandy loam; g r a n u l a r s t r u c t u r e ; p l e n t i f u l medium and f i n e r o o t s ; abrupt, way boundary; h o r i z o n t h i c k n e s s 7.6 cm to 23.0 cm; pH 4.2 to 4.9.  1  C l a s s e s used f o r r o c k fragments a r e o u t l i n e d  Appendix II .  i n T a b l e II,  83a  Figure 23.  A s o i l p r o f i l e i n a swamp f i r stand. The L-F-H layer i s r e l a t i v e l y thick and composed of fibrous moss peat. The upper B horizon i s dark, showing i l l u v i a t i o n of organic matter leached from above. ( Photo by Roy )  83b  84 Mean  Horizons  Description  Depth  (cm)  Most drained These  soils  soils,  horizon  14.2-25.3  y e l l o w i s h r e d (5YR 4/6, d r y ) t o d a r k r e d d i s h b r o w n (2.5YR 3/4, m o i s t ) s i l t y l o a m t o l o a m ; 0% t o 5% g r a v e l a n d c o b b l e s ; g r a n u l a r s t r u c t u r e ; compacted; few t o v e r y few medium a n d f i n e r o o t s ; a v e r a g e maximum r o o t i n g d e p t h , 29.2 cm; c l e a r , wavy b o u n d a r y ; h o r i z o n t h i c k n e s s 8.0 cm t o 15.0 cm; pH 4.8 t o 5.1.  25.3  y e l l o w i s h r e d (5YR 5/2 d r y , 5YR 4/8, m o i s t ) s i l t y l o a m t o l o a m y s a n d ; 5% t o 25% g r a v e l a n d 0% t o 5% c o b b l e s ; granular s t r u c t u r e ; compacted; r o o t s a b s e n t ; pH 5.0 t o 5.7.  black that like  composed  encountered.  spruce appear  those  Below t h i s  as  a r e found  saturated  beneath  o f mixed  Morphological  stands  peat, horizon  features  i n depressions,  f o rat least  swamp  f i r stands,  part  of these  soil  o f the year.  have a t h i c k L-F-H  beneath which seepage B and C h o r i z o n s  on p o o r l y  i s usually  a r e developed.  profiles  may b e  summarized  follows:  Horizon  Mean  Depth  Description  (cm) L-F-H  - 0  d a r k r e d d i s h b r o w n (5YR 2/2, d r y , m o i s t ) m i x e d p e a t ; commonly w a t e r s a t u r a t e d ; a b u n d a n t c o a r s e , medium a n d f i n e r o o t s ; a b r u p t , smooth boundary; h o r i z o n t h i c k n e s s 20 cm t o 104 cm; pH 3.2 t o 4.5.  0 - 19.7  y e l l o w i s h r e d (5YR 5/6, d r y ) t o r e d d i s h b r o w n (5YR 4/4, m o i s t ) s i l t y l o a m t o s a n d y l o a m ; 0% t o 5% g r a v e l ; g r a n u l a r s t r u c t u r e ; compacted; v e r y few f i n e r o o t s ; a v e r a g e maximum r o o t i n g d e p t h , 47.1 cm; c l e a r , wavy b o u n d a r y ; h o r i z o n t h i c k n e s s 10.4 cm t o 35.6 cm; pH 4.4 t o 4.9.  55.8  85  Horizon  Description  Mean Depth (cm) 19.7  +  p a l e brown (10YR 6/3, d r y ) to dark brown (10YR 4/3, m o i s t ) s i l t y loam to sandy loam; 5% t o 25% g r a v e l and c o b b l e s ; g r a n u l a r s t r u c t u r e ; compacted, r o o t s absent; pH 4.9 to 5.6.  Some o f the b l a c k spruce  stands  r i d g e s ; the s o i l s here a r e d i f f e r e n t are described separately.  s t u d i e d a r e l o c a t e d on low  from those  The s o i l s on r i d g e s have a t h i n n e r L-F-H  h o r i z o n , and u n l i k e the w e t t e r b l a c k spruce The  i n l o w - l y i n g areas and  s o i l s , have an Ae h o r i z o n .  B and C h o r i z o n s o f the s o i l s on r i d g e s a r e v e r y stony,  i s not u s u a l l y encountered.  and seepage  The p r o f i l e o f these may be summarized as  follows:  Description  Horizon  Mean Depth (cm)  L-F-H  14.2  - 0  l i t t e r of c o n i f e r o u s needles and herbaceous m a t e r i a l , u n d e r l a i n by v e r y dark brown f i b r o u s mor humus; white f u n g a l hyphare p r e s e n t ; abundant r o o t s o f a l l s i z e s ; boundary smooth and abrupt; h o r i z o n t h i c k n e s s 12.7 cm t o 15.2.cm; pH 4.5 t o 4.7.  Ae  0 -  5.0  gray t o v e r y dark gray s i l t y loam to sandy loam; p l e n t i f u l medium and f i n e r o o t s ; g r a n u l a r s t r u c t u r e ; boundary abrupt and smooth; t h i c k n e s s 2.5 cm to 7.6 cm, pH 4.6.  5.0 - 24.1  24.1  +  dark r e d d i s h brown sandy loam; very f i n e r o o t s ; mean r o o t i n g depth 23.3 cm; 5% to 25% g r a v e l and c o b b l e s ; g r a n u l a r s t r u c t u r e ; compacted; boundary g r a d u a l and i r r e g u l a r ; h o r i z o n t h i c k n e s s 17.8 cm t o 20.3 cm; pH 5.3. dark brown sandy loam; r o o t s absent; 25% to 50% g r a v e l , 5% to 25% c o b b l e s ; g r a n u l a r s t r u c t u r e ; compacted; pH 5.05 to 5.50.  2. The  P h y s i c a l and  Chemical  t e x t u r e of m i n e r a l s o i l s beneath upland  w i t h depth.  a v e r a g i n g 11.70% of a l l t h r e e h o r i z o n s . (avg. 48.59%) and  less clay  the h i g h e s t c l a y  sand  content,  the C h o r i z o n has  the  (avg. 60.03%) of the t h r e e .  The average  i s not as great i n swamp f i r  sand c o n t e n t here v a r i e s from 51.67% i n the B  h o r i z o n to 54.50% i n the C h o r i z o n ( T a b l e 11 ) and average  varies  B h o r i z o n s o i l s have more sand  (avg. 5.66%), and  T e x t u r a l v a r i a t i o n w i t h depth soils.  f i r stands  The uppermost m i n e r a l h o r i z o n , the Ae, has the lowest  c o n t e n t , a v e r a g i n g 44.50% ( T a b l e 10 ), and  most sand  Characteristics  of 8.03%  i n the B to 5.00%  c l a y ranges  from  an  i n the C h o r i z o n .  The m i n e r a l s o i l s beneath b l a c k spruce stands i n d e p r e s s i o n s a r e more f i n e l y averages  o n l y 29.90% i n the B h o r i z o n s o i l s and  while s i l t s o i l s may  forms an average  of about 60%  i n both  32.0%  Sand content i n the C h o r i z o n ,  (Table 1 2 . ) .  These  thus be more p o o r l y d r a i n e d than those beneath the o t h e r  vegetation  types.  Soil a r e not  t e x t u r e d than the o t h e r s o i l groups.  t e x t u r e d a t a f o r s o i l s o f b l a c k spruce stands on r i d g e s  available. A v a i l a b l e water, a measure of a s o i l s ' a b i l i t y to r e t a i n water  in  a form t h a t can be e x t r a c t e d by p l a n t s , i s d i r e c t l y  c o n t e n t s of s i l t ,  c l a y , and o r g a n i c matter.  correlated  In a l l of the  a n a l y z e d , a v a i l a b l e water i s h i g h e s t i n the o r g a n i c L-F-H upland of  f i r s o i l s , t h i s h o r i z o n has an average  23.36%.' M i n e r a l s o i l s have much lower  h o r i z o n of these s o i l s having an average  soils horizon.  a v a i l a b l e water  In  percentage  a v a i l a b l e water, the B of 10.03%.  with  A v a i l a b l e water percentages soils  are s l i g h t l y  f o r t h e L-F-H peat o f swamp f i r  lower, a v e r a g i n g 15.51%, w h i l e those f o r t h e B and C  h o r i z o n s , a v e r a g i n g 13.11% and 12.22% r e s p e c t i v e l y , a r e s i m i l a r to those of  t h e upland  f i r soils.  B l a c k spruce s o i l s percentages  i n d e p r e s s i o n s have h i g h e r A v a i l a b l e Water  than t h e o t h e r P l a t e a u f o r e s t s o i l s .  The L-F-H averages  37.89%, and the m i n e r a l B and C h o r i z o n s have f a i r l y h i g h a v e r a g i n g 31.58 and 16.73 r e s p e c t i v e l y . percentages  percentages,  The h i g h A v a i l a b l e Water  o f these h o r i z o n s r e l a t i v e to those o f t h e o t h e r s o i l s i s  perhaps r e l a t e d  to t h e f a c t t h a t t h e b l a c k spruce s o i l s  have h i g h  silt  contents. A v a i l a b l e Water percentages on r i d g e s a r e lower  determined  than the b l a c k spruce s o i l s  f o r b l a c k spruce  soils  i n d e p r e s s i o n s , but t h e  d a t a a r e too few t o be c o n s i d e r e d i n d i c a t i v e of a poorer a b i l i t y t o r e t a i n water ( T a b l e l 3 ) . Organic matter  i n t h e L-F-H h o r i z o n o f upland  from 30.19% t o 89.92%, and averages  64.75%.  f i r soils  Some o f t h e lower  varies  values  may be a r e s u l t o f p a r t i a l i n t e r m i x i n g o f m i n e r a l and o r g a n i c matter by s o i l organisms. lowest  In t h e m i n e r a l h o r i z o n s , o r g a n i c matter  content i s  i n t h e l e a c h e d Ae, a v e r a g i n g 4.19%, and h i g h e s t i n the B  h o r i z o n , a v e r a g i n g 5.90%, p r o b a b l y a r e s u l t o f i l l u v i a t i o n . The L-F-H o f swamp fjir s o i l s content of fir  than t h a t o f upland  has a h i g h e r o r g a n i c  f i r soils,  l e s s o r g a n i c and m i n e r a l s o i l m i x i n g soils.'  soils  Organic matter  matter  a v e r a g i n g 73.51%, perhaps because i n t h e t h i c k e r L-F-H of swamp  c o n t e n t s i n t h e m i n e r a l h o r i z o n s of these  a r e comparable to those o f t h e upland  f i r soils.  Again,  the B  T a b l e 10 .  Horizon  L-F-H  Ae  A  b  R  C  N A' R  B  C  P h y s i c a l and Chemical  C h a r a c t e r i s t i c s of Upland  F i r Soils  Available Water (%)  Sand (%)  Silt (%)  Clay (%)  Organic Matter (%)  Total Nitrogen (%)  C - N Ratio  4  -  -  -  4  -  -  23.36  -  -  -  64.75  -  -  13.41 -30.41  -  -  -  30.19 -89.92  2  2  2  2  9  8  8  12.87  44.50  .43.80  11.70  4.19  0.12  31.37  5.31  37.60  37.40  11.20  1.30  0.06  18.00  -20.45  -51.40  -50.20  -12.20  -8.21  -0.32  -90.00  10  8  8  -  N  3  3  3  3  A  10.03  48.59  45.73  5.66  5.90  0.10  43.87  R  6.88  43.00  33.80  3.00  3.27  0.07  32.00  -12.89  -57.40  -59.00  -8.80  -12.58  -0.17  -62.00  N  3  3  3  3  4  2  2  A  15.65  60.03  31.63  8.33  4.44  0.05  59.00  R  12.30  51.30  23.00  4.20  1.82  0.04  30.00  -21.40  -67.40  -44.50  -11.20  -8.80  -0.06  -88.00  oo oo  Table 10 .  Ca (meq/lOOg)  Mg (meq/lOOg)  19  19  19  19  12  0.70  0.81  1.24  0.68  4.24  0.22  0.20  0.23  0.18  3.40  -  -1.61  -2.02  -2.26  -1.52  -4.60  2  8  12  12  12  12  A-  18.65  349  0.22  0.13  0.24  0.06  4.66  R  15.50  125  0.08  0.02  0.06  0.03  4.20  -21.80  -950  -0.33  -0.29  -0.55  .> -0.17  -5.20  C.E.C.  d  N  2  A  97.24  R  80.22 -114.27  Ae  B  C  K (meq/lOOg)  Na (meq/lOOg)  Horizon L-F-H  (Continued)  N  p (ppm) _  pH  9  N  3  8  20  20  20  20  12.-  A  36.53  540  0.22  0.10  0.12  0.07  5.12  R  27.10  270  0.03  0.01  0.10  0.03  4.50  -44.02  -920  -1.04  -0.32  -0.26  -0.37  -5.75  N  2  2  20  20  20  20  12  A  12.14  385  0.12  0.07  0.05  0.05  5.34  R  11.82  375  0.03  0.01  0.02  0.02  5.00  -12.47  -395  -0.40  -0.28  -0.10  -0.18  -5.85  Number of samples.  'Average.  C  Range.  N a t i o n Exchange Capacity expressed i n meq/lOOg. 00 VD  T a b l e 11 .  P h y s i c a l and Chemical  Available Water  Horizon  (%)  L-F-H  N A  Sand . (%)  4  a  15.51  b  R°  B  C  4  4  Total Nitrogen  Clay  (%)  (%)  (%)  (%)  -  5  3  -  7.12  _  N  Organic Matter  Silt  ' .  -  -27.64 Ae  C h a r a c t e r i s t i c s of Swamp F i r S o i l s  -  -  -  - .  4  3  ,73.51  1.72  25.00  56.46  1.39  18.00  -93.67  -1.91  -29.00  5  4  C - N Ratio  2  2  A  12.93  53.25  39.20  7.39  3.69  0.08  34.00  R  4.44  45.00  34.20  4.00  1.50  , 0.05  33.00  -21.12  -58.80  -51.00  -10.40  -7.50  -0.12  -35.00  5  -  N  5  5  5  5  A  13.11  51.67  40.27  8.03  4.87  R  2.05  34.00  20.40  2.80  0.64  -22.92  -76.80  -62.00  -15.00  -11.10  N  • 2  2  2  A R  2  .  3  12.22  54.50  40.50  5.00  2.95  7.51  33.00  20.00  4.00  1.75  -16.94  -76.00  -61.00  -6.00  -4.17  Table 11 .  C.E.C.  Horizon L-F-H  1  N A  99.3 -  R  Ae  C  Na (meq/lOOg)  Ca (meq/lOOg)  Mg (meq/lOOg)  K (meq/lOOg)  3  6  6  6  6  3  380  0.91  1.47  1.44  0.28  4.22  320  0.75  0.30  0.20  0.04  4.00  -480  -1.15  -2.70  -2.20  -0.82  -4.70  pH  3  2  5  5  5  5  3  A  20.52  232  0.18  0.29  0.25  0.04  4.63  8.02  140  0.05  0.04  0.07  0.03  4.20  -44.88  -325  -0.33  -0.74  -0.68  -0.05  -4.90  N  3  1  5  5  5  5  3  A  10.94  140  0.13  0.25  0.07  0.05  5.00  R  9.32  -  0.03  0.01  0.03  0.02  4.80  -13.22  -  -0.31  -0.86  -0.20  -0.09  -5.10  N  2  1  3  3  3  3  3  A  11.97  545  0.21  0.05  0.10  0.09  5.36  R  9.76  -  0.10  0.02  0.03  0.06  5.00  -14.20  -  -0.30  .-0.09  -0.25  -0.15  -5.70  Number of samples. Average.  P (ppm)  N R ~  B  (Continued)  Range. ^Cation Exchange Capacity (meq/lOOg).  Table 12 . P h y s i c a l and Chemical C h a r a c t e r i s t i c s of Black Spruce S o i l s i n Depressions  Horizon L-F-H  B  C  Available Water (%)  Sand (%)  Silt (%)  Clay (%)  Organic Matter (%)  Total Nitrogen (%)  C - N Ratio  N  a  2  -  -  -  2  -  -  A  b  37.89  -  -  -  94.31  -  -  R  C  33.19  -  -  -  91.97  -  -  -42.59  -  -  -  -96.65  -  -  N  2  2  2  2  2  1  1  A  31.58  29.90  61.20  11.60  9.46  1.91  32.00  R  28.19  27.80  50.80  6.00  9.02  -  -  -34.97  -32.00  -71.60  -17.20  -9.90  -  -  ,  s  N  1  1  1  1  1  -  -  A  16.73  32.00  62.80  5.20  4.23  -  -  R  -  -  -  -  —  —  —  vO  Table U .  C. E. C.  Horizon L-F-H  B  Na (meq/lOOg)  Ca (meq/lOOg)  Mg (meq/lOOg)  -  5  5  5  5  5  pH  2  A  104.40  -  0.86  1.21  3.58  0.14  4.00  R  91.72  -  0.60  0.47  0.98  0.04  3.20  -117.09  -  -1.27  -1.87  -6.25  -0.42  -4.50  1  1  5  5  5  5  5  24.28  145  0.18  0.43  0.56  0.07  4.73  -  -  0.05  0.09  0.11  0.03  4.92  -  -  -0.33  -0.95  -1.87  - -0.10  -4.90  N  1  -  5  5  5  5  5"  A  13.66  -  0.22  0.11  0.13  0.11  5.22  R  -  -  0.05  0.05  0.03  0.04  4.90  -  -  -0.38  -0.15  -0.34  -0.23  -5.63  N R  'Number of samples. 'Average.  K (meq/lOOg)  P (ppm)  N  A~.=-  C  (Continued)  Range. ^Cation Exchange Capacity (meq/lOOg).  Table 13  Available Water  Horizon L-F-H  Ae  Silt  (%)  (%)  Clay (%)  Total Nitrogen  C - N Ratio  (%)  (%)  1  1  1  0.09  41  a  1  -  -  A  b  25.41  -  -  R  C  -  -  -  -  -  -  -  1  1  1  -  -  -  0.90  0.04  _  _  '1  N R  C  Sand  (%)  Organic Matter  N  A... _  B  P h y s i c a l and Chemical C h a r a c t e r i s t i c s of Black Spruce S o i l s on Ridges  -  N  1  A  20.23  -  R  -  N A R  63.4  '  22  1  1  -  6.54  0.09  45 -  -  _  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  —  —  -  -  VO  •c-  Table 13 . (Continued) C.E.C.  Horizon L-F-H  Ae  d  C  Na (meq/lOOg)  Mg (meq/lOOg)  K .(meq/100g) 2  2  0.13 0.05 -0.21  4.65 4.55 -4.75  pH  1 13.44  1  2  225  R  -  -  ' -  -  . 0.27 0.19 -0.36  -0.37  2 0.26 0.10 -0.42  -  1 40  1 0.20  1 0.10  1 0.12  1 0.02  1 4.60  -  -  -  -  -  -  -  1 13.88  1 420  2 0.20  -  -  -  -  -  -  -  -  -  -  N A R  N A R  2 0.28 0.19  2 0.27  2 0.04  2 5.32  -  •2 0.15 0.14  0.03  -  5.30  -  -0.17  -0.51  -  -5.35  2 0.15  2 0.06  2 0.04  2 5.27  -  2 0.12 0.06  -  -  -  -0.18  -  -  0.03 -0.05  5.05 -5.50  'Number of samples. Average.  Ca (meq/lOOg)  N A  N . A R  B  P (ppm)  Range. d  Cation Exchange Capacity (meq/lOOg).  horizon while  soils  have t h e h i g h e s t  organic matter  t h e Ae and C h o r i z o n s have l e s s ,  content,  4.87%,  averaging  w i t h means o f 3.69%  and  2.95%  respectively. Organic in  depressions,  a higher average  matter  organic matter  9.46%,  of  indicated  i s similar  Plateau,  the a v a i l a b i l i t y  ratios Total  ranges  from  t h e Ae.  Total  ratios, these  averaging  (0.90%) w h i l e  25.00,  B  f i r soils. soils  horizons  o f upland  of the losses.  carbon-  ratios  f o r these  i n t h e Ae t o  59.00  soils  above, a v e r a g i n g a r e lower.  f i r soils  t o an average are f a i r l y  of  0.12%  high,  i n t h e C. f i r soils  1.72%,  while  T h e Ae o f t h e s e  i s higher  than  carbon-nitrogen  soils  i s similar  f i r soils.  o n e n i t r o g e n d e t e r m i n a t i o n was made f r o m  i n depressions;  the  r a t e s and l e a c h i n g  i n the C horizon,  respects to that of upland Ohly  soils  soils  soils  high.  n i t r o g e n o f t h e L - F - H o f swamp  of the mineral  matter  T h e Ae h o r i z o n o f t h e s e  o f n i t r o g e n may b e l o w , s i n c e  o f 0.05%  31.37  from  w i t h an  the black spruce  to the B of upland  nitrogen of the mineral  Carbon-nitrogen  soils,  a r e low i n t h e f o r e s t  are often f a i r l y  an average  means r a n g i n g  that  nitrogen levels  than  organic matter  respect  group a l s o has  on r i d g e s f o r o r g a n i c  (Table 13).  little  soils  to that of the others.  organic matter  63.4%  i n this  soils  of spruce  of this  the B of other  perhaps because o f slow decomposition  In a d d i t i o n , nitrogen  spruce  t h e L-F-H has l e s s  Total  in  of black  on r i d g e s h a s v e r y  horizon  than  i n t h e peat  B horizon  The  the C i s similar  depressions, averaging  soils  in  content  while  are highest  94.31%.  averaging  Analysis  in  contents  t h e B h o r i z o n had a t o t a l  black  spruce  n i t r o g e n content of  1.91%, and a carbon-nitrogen ratio of 32.00. Total nitrogen i n one of the black spruce soils on ridges was measured at 0.09% i n the L-F-H and B horizons, and 0.04% i n the Ae. Carbon-nitrogen ratios for these three horizons are 41.00, 45.00, and 22.00 respectively. The Plateau s o i l s have low concentrations of exchangeable calcium, magnesium, potassium and sodium, perhaps because of low concentrations i n the parent material as well as leaching losses. In the L-F-H horizon of upland f i r s o i l s , exchangeable calcium and magnesium are the most abundant, with averages of 1.47 meq/100 g and 1.44 meq/100 g, respectively. Exchangeable sodium i s s l i g h t l y less abundant i n this horizon (avg. 0.91 meq/100 g) and potassium i s the least abundant, averaging 0.28 meq/100 g. In the Ae horizon, cation concentrations are lower, ranging from an average of 0.06 meq/100 g for potassium, to an average of 0.24 meq/100 g for magnesium.  Concentrations  are similar i n the B horizon with the exception of magnesium, which has a lower average concentration of 0.12 meq/100 g. Cation levels are lowest in the C horizon; here averages range from 0.05 meq/100 g for potassium and magnesium to 0.12 meq/100 g for sodium. In the L-F-H of swamp f i r s o i l s , calcium and magnesium are the most abundant, averaging 1.47 meq/100 g and 1.44 meq/100 g respectively, followed by sodium, with an average of 0.91 meq/100 g, and potassium with an average of 0.28 meq/100 g. As i n upland f i r s o i l s , the Ae i s poorer i n a l l four cations; average concentrations range from 0.04 meq/100 g for potassium to 0.29 meq/100 g for calcium.  The B  horizon of these s o i l s i s similar to the Ae i n levels of a l l except  98  magnesium, which i s lower here, averaging only 0.07 meq/100 g. Unlike upland f i r s o i l s , magnesium and potassium levels are s l i g h t l y higher i n the C horizon than i n the B horizon, averaging 0.10 meq/100 g and 0.09 meq/100 g, respectively, while sodium and calcium are lower i n the C, having averages of 0.21 meq/100 g and 0.05 meq/100 g respectively. Exchangeable sodium and calcium are s l i g h t l y more concentrated in the L-F-H of black spruce soils i n depressions than i n swamp f i r and upland f i r s o i l s . soils.  Potassium levels, however, are lower i n black spruce  In the black spruce s o i l s , sodium averages 0.86 meq/100 g,  calcium has a mean of 1.21 meq/100 g, and potassium averages 0.14 meq/100 g. Magnesium, however, has a very high average of 3.58 meq/100 g i n this horizon. The B horizon of these s o i l s i s also high i n magnesium, which averages 56 meq/100 g. Whereas average concentrations of potassium and sodium i n this horizon at 0.07 meq/100 g and 0.18 meq/100 g, are similar to those of the B of swamp f i r s o i l s , calcium i s more abundant here, averaging 0.43 meq/100 g. In the C horizon, levels of a l l measured cations except calcium are similar to those of the C of swamp f i r s o i l s .  Calcium i s more abundant i n the  black spruce s o i l s , averaging 0.11 meq/100 g. Although only two examples of black spruce s o i l s on ridges were examined, cation levels appear to be lower i n the L-F-H of these than i n other forest s o i l s of/, the Plateau. Averages i n the black spruce soils range from 0.13 meq/100 g for potassium, to 0.28 meq/100 g for calcium. Single determinations for each cation i n the Ae indicate lower cation concentrations here.  These range from 0.02 meq/100 g for  potassium to 0.20 meq/100 g for sodium.  Average levels are higher i n  99 the Ae of other s o i l groups, but are based on more determinations. The B horizon has similar average concentrations of potassium and sodium to those of the B of most other s o i l groups, while calcium levels, averaging 0.15 meq/100 g are most similar to that of upland f i r s o i l s . Magnesium has an average of 0.27 meq/100 g, higher than that of upland f i r and swamp f i r s o i l s , but lower than black spruce s o i l s i n depressions.  In the C layer of black spruce s o i l s on ridges, average  concentrations of sodium, magnesium, and potassium are similar to those of upland f i r soils while the average for calcium i s s l i g h t l y higher i n the black spruce s o i l s . Cation Exchange Capacities (C.E.C.) of the Plateau s o i l s are generally highest i n the L-F-H where organic matter contents are high, and lowest i n the C horizons where organic matter contents are low. In upland f i r s o i l s , the L-F-H has an average C.E.C. of 97.24 meq/100 g,. the B averages 36.53 meq/100 g, and the Ae and C have means of 18.65 meq/100 g and 12.14 meq/100 g respectively (Table 10 ). The L-F-H, Ae, and C horizons of swamp f i r s o i l s have average Cation Exchange Capacities (Table 11 ) similar to those of upland f i r s o i l s , while the B horizon of swamp f i r s o i l s has a lower average C.E.C. (10.94 meq/100 g) than the upland f i r s o i l s . The L-F-H of black spruce s o i l s i n depressions has an average Cation Exchange Capacity of 3,04.40 meq/100 g, higher than the L-F-H of a l l other forest s o i l s , while the B and C horizons have averages similar to those of swamp f i r s o i l s (Table 12. ). Only two determinations of C.E.C. were made for black spruce s o i l s on ridges (Table 13 ); these are both much lower than those above.  100 Average of  upland  in  t h e Ae,  levels  f i r soils  i n t h e L-F-H  t h e Ae,  with  horizons  of  these  The  few  ,13  with  of  t h e Ae  t h e L-F-H average  PH  and  an  similar  and  average  pH  of  and  545  and  ppm  levels  vegetation  are  4.66,  ppm,  and  for  phosphorous phosphorus  i s less  lowest  i n the  are  i n t h e L-F-H  B and  C an  soils  of other  4.65,  B and  of  ( T a b l e II ) .  are  similar  acid,  a result  has  C h o r i z o n pH  an  are  average  of  acid  where  an  average  pH  readings similarly  o f 4.63,  a r e more a c i d  The  (  and  horizons,  an  than  acid,  the  the  concentrations of a c i d  o f t h e L-F-H. 4.73,  to  B  the  L-F-H  pH  averages  C h o r i z o n has  an  other  organic only  average  pH  soils.  h o r i z o n of b l a c k spruce slightly  higher  than  an  5.36.  i n depressions  because of h i g h  peat  t h e L-F-H  t h e Ae  average  C  generally increase  Swamp f i r s o i l s  o f 4.52,  B averages  L-F-H  the  in  soils  i n these  analyzed  f i r soils, and  is  abundant  respectively spruce  lowest  types.  soils  respectively.  the  thick  the  to those The  ppm,  made f o r b l a c k  forest  average  spruce  i n the  that of  ppm  In upland  5.34  5.00,  540  Single determinations  140  values  studied, probably  material  380  that phosphorus  averages  having  of  i s available  horizons  c o n i f e r o u s o r g a n i c m a t e r i a l , l e a c h i n g , and  depth.  Black  4.00,  of  averaging  c o n c e n t r a t i o n s a r e h i g h e s t and  slightly  5.12  are  the P l a t e a u  material.  organic matter  soils  soils  ppm.  i n the m i n e r a l  I n swamp f i r s o i l s ,  L-F-H, a v e r a g i n g 232  B,  data  soils.  determinations  of  phosphorus  i n the No  beneath other  accumulation  average  ppm.  these  ) suggest  soils  4.24,  of  a mean o f  All  parent  349  i n the  of  ( T a b l e s 12  an  are highest  averaging  most a b u n d a n t  those  concentrations of  soils  that of  on  r i d g e s has  the upland  an  f i r soils,  101 but the mineral horizons of the two s o i l groups have s i m i l a r pH readings. 3. D i s c u s s i o n The p r o f i l e d e s c r i p t i o n s and a n a l y t i c a l r e s u l t s presented above i n d i c a t e a number of d i f f e r e n c e s among the s o i l groups; many of these are  s i g n i f i c a n t w i t h respect to vegetation. One of the more obvious d i f f e r e n c e s l i e s i n the accumulation of  organic matter i n the L-F-H horizons. Whereas the upland f i r and black spruce s o i l s on ridges have r e l a t i v e l y t h i n L-F-H horizons, those beneath swamp f i r stands and black spruce stands i n depressions have very t h i c k organic horizons. These s o i l s are located i n areas where seepage i s abundant, and are water-saturated f o r much of the year.  Lutz  and Chandler (1946) reported that such conditions depress s o i l temperatures and create anaerobic c o n d i t i o n s , r e s u l t i n g i n low decomposition rates and an accumulation of r e l a t i v e l y undecomposed peat. The thickness of the organic horizon, except as a p o t e n t i a l seedbed, i s i n i t s e l f l e s s important to vegetation, than are c h a r a c t e r i s t i c s such as nutrient content and a v a i l a b i l i t y , water content, and s o i l aeration. In the t h i c k organic horizons of the swamp f i r s o i l s and black spruce s o i l s i n depressions concentrations of most of the exchangeable cations are equal to or higher than those of upland f i r soils.  Exchangeable magnesium, calcium, and sodium are more  concentrated i n the peat soils!, while i n these potassium i s generally l e s s concentrated. High s o i l water content as observed i n the swamp f i r and black spruce s o i l s i s u s u a l l y accompanied by poor s o i l a e r a t i o n , which i n turn  102 i s p a r t i a l l y responsible f o r the accumulation aerated s o i l s are unfavourable  of organic matter.  Poorly  f o r many p l a n t s , low oxygen and high  CO^ l e v e l s r e s u l t i n g i n poor root growth, a decreased absorption of both water and n u t r i e n t s and often the accumulation (Buckman and Brady, 1960),  of t o x i c compounds,  Since species d i f f e r widely i n terms of  tolerance of oxygen d e f i c i e n c i e s (Lutz and Chandler, 1946), judgments concerning the s u i t a b i l i t y of s o i l s to p a r t i c u l a r species on t h i s b a s i s must be made w i t h due consideration of the species'  requirements.  Although oxygen concentrations were not measured i n t h i s study, the abundant seepage observed i n the l o w - l y i n g areas on the Plateau suggests the s o i l s there are poorly aerated and i n t h i s respect l e s s favourable f o r vegetation than those i n higher areas of b e t t e r drainage. The combination of poor a e r a t i o n and high a c i d i t y that may e x i s t i n swamp f i r and black spruce s o i l s i n depressions often i n h i b i t s ammonification and n i t r i f i c a t i o n .  A v a i l a b l e nitrogen l e v e l s may also be  lowered by d e n i t r i f i c a t i o n , the reduction of n i t r a t e s to gaseous nitrogen,  (Lutz and Chandler, 1946).  Consequently, although  total  nitrogen concentrations obtained i n t h i s study f o r the poorly drained s o i l s are comparable to those f o r upland f i r s o i l s , a v a i l a b l e nitrogen l e v e l s may be low i n the wet areas. A l l of the Plateau s o i l s examined, with the exception of those beneath black spruce stands ih depressions, have Ae horizons, a feature of podzol s o i l s .  Podzol s o i l s are formed by a process i n which  organic acids are transported downward through the s o i l p r o f i l e by seepage, removing bases from the uppermost mineral s o i l .  These are  replaced by hydrogen, and s o i l a c i d i t y here increases, leading to an  103  i n s t a b i l i t y of iron and aluminum, which, together with c o l l o i d a l organic matter, tend to settle i n the lower levels of the p r o f i l e , (Lutz and Chandler, 1946).  Podzol s o i l s are usually recognized, then, by an  accumulation of iron and aluminum complexes i n the B horizons.  Since  neither of these have been measured i n this study, no definite c l a s s i f i c a t i o n of the Plateau s o i l s has been made. The presence of an Ae horizon and the reddish colour of the B horizon i n many of the s o i l s does suggest, however, that leaching of the upper s o i l and i l l u v i a t i o n of the lower horizons i s taking place.  The expected lower cation  concentrations i n the Ae compared to those of the B horizon are not always found i n the Plateau s o i l s .  In swamp f i r and upland f i r s o i l s ,  the reverse i s sometimes found, indicating that they may generally be juvenile. Although the black spruce s o i l s on ridges and the black spruce soils i n depressions support the same vegetation type, the two d i f f e r in many respects.  Whereas the s o i l s i n depressions are very wet and  have thick organic horizons, those on ridges appear to have better drainage and have much thinner organic horizons.  Unlike those of low-  lying areas, the L-F-H of soils on ridges have lower organic matter contents and cation concentrations than any of the other s o i l s studied. Few trends are apparent among the results of analyses for exchangeable cations, beyond /those mentioned above.  In the s o i l s of  humid regions, the four cations measured usually occur i n decreasing order of abundance as follows: calcium, magnesium, potassium, and sodium, determined by the relative strengths by which each cation i s absorbed to the s o i l micelles, (Lutz and Chandler, 1946).  In the L-F-H  104 of  a l l except  are  t h e most  while  spruce  abundant.  This  i n t h e Ae o f u p l a n d  t h e most In  the black  concentrated,  the three  abundant,  concentrations  than  true  f i r soils,  of a l l s o i l s ,  penetrate  no d e e p e r  are  particularly  the  B and C h o r i z o n s  impermeable flowing  shallow  the s o i l  i n black  spruce  by the frequent a t t h e upper  conditions,  i n a number o f u p l a n d  nitrogen,  penetration  a n d , i n many  soils  That  these  observation  soils.  soils, Root  on r i d g e s .  i s also hindered  summary, c o n c e n t r a t i o n s  f i r soils  systems  In a l l s o i l s may b e  of l a t e r a l  by v e r y  seepage  stony  and a l l b l a c k  Plateau  beneath black poor  are nutritionally  spruce  stands  than  those  spruce  poor.  concentrations  likely  t o be p o o r l y  equal  aerated  Among  or ridges are the least  soil spruce  stony.  these,  total  soils  of the  the soils  favourable,  being  The o r g a n i c  s o i l s oi  a n d swamp f i r a s s o c i a t i o n a r e p o s s i b l y  o f the upland  cation  cations,  indicate the forest  i n c a t i o n s and n i t r p g e n , and v e r y  low-lying black  fertile  o f exchangeable  and c a r b o n n i t r o g e n r a t i o s  Cape B r e t o n  the  i n a l l of the Plateau  on r i d g e s . In  both  lower  B h o r i z o n , whereas t h e s o i l s  Root  soils  i s the least  of the B horizon.  t o be compacted.  beneath a r e dry. found  are juvenile.  cations.  the upper p a r t  appear  i s suggested  through  potassium  i n t h e L-F-H h o r i z o n s  than  calcium, i s  where i t has m a r k e d l y  Maximum r o o t i n g d e p t h s a r e s h a l l o w R o o t s a r e most a b u n d a n t  than  some o f t h e s o i l s  i n t h e Ae h o r i z o n s ,  the other  and magnesium  i n t h e Ae o f swamp f i r s o i l s ,  sodium, r a t h e r  suggesting  horizons  particularly  on r i d g e s , c a l c i u m  i s also  again  uppermost  soils  f i r a s s o c i a t i o n ; the former  t o those  o f the upland  and p e r h a p s n i t r o g e n  f i r soils,  poor.  less  have but are  105 Although the well-drained s o i l s have a c i d , greyish A horizons, i n d i c a t i v e of p o d z o l i z a t i o n , r e s u l t s suggest that the s o i l s are generally immature. In an e a r l i e r s e c t i o n , r e s u l t s of vegetation analyses from t h i s study are compared with d e s c r i p t i o n s of boreal f o r e s t s i n southeastern Quebec (Linteau, 1955) and c e n t r a l Newfoundland (Damman, 1964). These studies and an a d d i t i o n a l paper f o r Newfoundland (Damman, 1971) include d e s c r i p t i o n s of s o i l s beneath the various f o r e s t types, and i t seems appropriate to b r i e f l y compare these with the r e s u l t s obtained for the Plateau. S o i l s beneath Abies balsamea f o r e s t s i n Quebec have thinner L-H and Ae horizons than those on the Plateau.  In a d d i t i o n , the L-H of  the Quebec s o i l s i s l e s s a c i d , and has higher concentrations of exchangeable magnesium, potassium, and calcium than that of s o i l s beneath upland f i r s o i l s on the Plateau.  Phosphorus l e v e l s , on the  other hand, are much lower i n the Quebec s o i l s . Poorly-drained s o i l s beneath Picea mariana i n Quebec s i m i l a r l y have thinner and l e s s acid organic horizons than those of the Plateau, and have much higher concentrations of exchangeable calcium.  Exchange-  able potassium l e v e l s , however, are s i m i l a r i n the two s o i l types, and both magnesium and phosphorus l e v e l s are lower i n the Quebec s o i l s . Although no nitrogen), determinations are a v a i l a b l e f o r the humus of upland f i r and poorly-drained black spruce s o i l s on the Plateau, l e v e l s i n the Quebec s o i l s are s i m i l a r to the average L-F-H of swamp f i r s o i l s . Forest s o i l s on the Plateau beneath upland f i r stands  106 morphologically resemble well-drained s o i l s i n Newfoundland classed as Iron Podzols (Damman, 1964).  These are found beneath balsam f i r f o r e s t s ,  and l i k e the s o i l s of the Plateau, have a f a i r l y t h i c k , acid L-F-H horizon (11.5 cm.) underlain by Ae and B horizons, extending to a depth of 38 cm.  As i n the Plateau s o i l s , a c i d i t y increases s l i g h t l y with  depth. The F and H horizons of A. balsamea  forest s o i l s i n Newfound-  land (Damman, 1971) have much higher concentrations of potassium and calcium than do those of the Plateau s o i l s , whereas the mineral horizons of the Newfoundland s o i l s , have lower l e v e l s of both of these cations than the Plateau s o i l s .  In the Newfoundland s o i l s , organic  matter contents (% l o s s on i g n i t i o n ) are lower i n the Ae horizon and higher i n the B horizon than i n the Plateau s o i l s , suggesting the Plateau s o i l s are more j u v e n i l e .  Phosphorus concentrations are much  lower i n a l l horizons i n the Newfoundland s o i l s than i n the Plateau soils. The Plateau s o i l s beneath black spruce stands on poorlydrained s i t e s are most s i m i l a r to those s o i l s i n Newfoundland classed as Peat Bog s o i l s (Damman, 1964).  In these, the peat l a y e r i s over  12 i n (30.5 cm) i n thickness, has low pH values of 4.0 or lower, and i s underlain by gleyed mineral s o i l having poor horizon development. The organic horizons^of s i m i l a r s o i l s beneath Kalmia  heath i n  Newfoundland (Damman, 1971) have higher concentrations of potassium and calcium than those of the black spruce s o i l s i n poorly-drained areas on the Plateau, whereas the B and C horizons of the Newfoundland are poorer i n these cations than those of the Plateau s o i l s .  107 In a d d i t i o n , Damman (1971) noted that root systems i n the Newfoundland s o i l s , as i n the Plateau s o i l s , are f a i r l y shallow.  In  the f i r f o r e s t s o i l s of Newfoundland nearly a l l of the l a r g e r roots were found w i t h i n 20 cm of the s o i l surface, few extending beyond the upper B horizons, and most of the small roots were concentrated i n the organic horizons. These comparisons i n d i c a t e , then, that the p r o f i l e s of s o i l s beneath upland f i r stands and those below black spruce stands i n depressions resemble those beneath s i m i l a r vegetation types i n Quebec and Newfoundland.  The Plateau s o i l s are generally more acid than those  of Quebec, and have l e s s calcium and magnesium i n the L-H l a y e r s than s o i l s i n both Quebec and Newfoundland.  .i  108  VI.  AUTECOLOGY OF MAJOR TREE SPECIES  The performance of major tree species i s an important feature of forest communities.  Factors such as reproductive success, growth  rates, and productivity, often reflect site conditions as well as characteristics of the stands themselves.  The following i s an  examination of some of these factors, displayed by four major tree species i n the three forest associations on the Plateau. 1. Abies  Abies  balsamea  (balsam f i r )  seedlings occur i n a l l three forest associations,  balsamea  but are most abundant in the upland f i r association.  In these stands,  seedbeds composed of several moss species and decaying wood appear to be favourable for seedling establishment, and densities of average 16,162 stems/ha (Table 14 ) .  A.  balsamea  Seedlings are much less abundant i n  the swamp f i r association, where densities average 5,950 stems/ha.  In  these stands, seedbeds consist largely of sphagnum mosses, whose thickness, moisture-retaining capacity, and high growth rate may hinder seed germination and seedling establishment. competition for light with low shrubs and probably severe, and  A.  balsamea  In black spruce stands, Picea  mariana  reproduction i s  seedlings are uncommon, averaging only  1,160 stems/ha. Although i n upland f i r stands densities of young seedlings are high, very'low sapling numbers (avg. 187 stems/ha) indicate high seedling mortality.  This may be a result of poor light conditions at  Table H .  Summary of Mensurational Data for Major Cape Breton Plateau Tree Species  Densities (stems/ha) Species  Basal  Association  Area (m /ha) 2  Seedlings upland f i r  swamp f i r  balsamea  black spruce  Picea  black spruce  mariana  Picea  upland f i r  glauca  swamp f i r  Betula  upland f i r  papyrifera swamp f i r  Live Trees  Height  (yrs)  (m)  16,162  187  1,390  41.1  56.0  9.6  7,550  0  925  31.7  26.0  3.3  -24,425  -450  -1,750  -52.2  -134.0  -13.8  A  5,950  1,212  842  22.9  93.2  8.0  R  1,400  425  550  16.7  54.0  3.9  -12,325  -2,275  -1,650  -49.7  -139.0  •12.0  A  1,160  400  100  0.4  R  700  0  0  -5,100  1,400  -400  -1.4  A  2,400  4,200  6,827"  13.8  44.2  2.7  R  100  2,500  4,700  8.6  24-80  -7,400  -5,900  •11,100  -17.8  A  105  7  11  0.6  R  0-300  0-50  0-75  0-4.9  R  Abies  Saplings  Age  0  A  337  77  75  2.6  R  100-675  0-175  0^175  0-6.1  A  1,360  355  33  1.2  R  0-3,250  0-2,475  0-125  0-18.9  A  702  260  5  0.1  R  0-3,325  0-1,325  0-5  0-0.1  1.8-3.7  Average Range These data represent individuals i n the B  1  stratum rather than i n the A strata.  o  110  ground levels, since  A.  saplings are common only i n areas where  balsamea  windfalls have created openings i n the tree strata. Swamp f i r stands have more open tree strata, and conditions appear to be much more favourable for the growth of young trees. Although  A.  balsamea  seedlings are less abundant here than i n upland  f i r stands, seedling survival i s probably greater, since sapling densities are higher, averaging 1,212 stems/ha. In black spruce stands  A.  balsamea  seedlings are very few, but  favourable light conditions probably compensate for other factors and saplings of this species average 400 stems/ha i n density, more than twice that of upland f i r stands. In the tree strata,  Abies  balsamea  i s most successful i n the  upland f i r association where l i v e trees have an average density of 2  1,390  stems/ha and an average t o t a l basal area of 41.1 m /ha.  In the  swamp f i r association, both densities and stand basal areas are lower, 2  averaging 842 stems/ha and 22.9 m /ha, respectively. In the black spruce association, exposure to adverse weather prevents most tree species from reaching tree height (3.5m), and densities of Abies  balsamea  i n the tree layer average only 100 stems/ha. 2  The total basal area of this species averages only 0.4 m /ha i n these stands. Graphs of the distribution of l i v e  A.  balsamea  trees among  diameter classes i n the upland f i r and swamp f i r associations (Fig.24 ) are i n some respects similar.  The curves have a similar shape, and  both indicate that i n both associations, the stem diameters of most A. balsamea  trees are f a i r l y similar.  Few trees with very small or very  45 40 -  5  10  15  20  Stem  Diameter  25  30  (cm)  I Figure  2<t. T h e D i s t r i b u t i o n Stem D i a m e t e r  Classes  i Fir  of Mature  Associations.  A b i e s balsamea  i n t h e Swamp F i r a n d  among Upland  112  large  diameters  suggests  that  particular  a r e found  i n either  the majority of trees  associations,  trees  a b u n d a n t , b u t i n swamp f i r s t a n d s ,  that  comprising  trees  are less  the upland  association these  not  abundant  f i r sites  vary  from  smaller trees  than  i n upland  always  accompanied  through  54 y e a r s  the  trees  but  a r e based  balsamea  those  class  average  9.6  heights  vary  m.  This  A.  f i r stands,  balsamea  that  suggesting  i n the upland f i r 56.0  years.  A  graph  i n c r e a s e s i n age a r e  t o have been  t r e e s measured  In a  suppressed,  than  association  range  3.9 m t o 12.0  comparison  height  and'diameter  stands  ( F i g s . 26, 2 7  data  Heights from  ).  tend  T h e s e show  that  suggest  f i r stands, resemble  similarly  m and  selected  o f 8.0  by l i n e a r  i n upland  slightly  s e l e c t e d by  3.3 m t o 13.8  illustrated  balsamea  t o be  of trees  m and have a n a v e r a g e  i s further f o r A.  i n upland  sample might  trees  I n t h e swamp f i r a s s o c i a t i o n ,  from  those  These d a t a  vary  closely.  A. balsamea  i n swamp f i r s t a n d s .  i n this  years.  A larger  f i r a s s o c i a t i o n more f i r stands,  i n swamp f i r s t a n d s  93.2  are older  on few d e t e r m i n a t i o n s .  In upland  diameter  growth appears  i n swamp f i r s t a n d s  than  a r e more a b u n d a n t , a n d  by c o r r e s p o n d i n g i n c r e a s e s i n diameter.  t o 139 y e a r s a n d a v e r a g e  of the upland  taller  a r e most  competition f o r l i g h t .  A g e s o f A.  that  to a  a r e more p r o d u c t i v e .  (Fig."2.5) i n d i c a t e s  number o f c a s e s d i a m e t e r  from  the stands belong  26 t o 134 y e a r s , a n d a v e r a g e  a g a i n s t D.B.H.  probably  generally  15 cm t o 20 cm i n d i a m e t e r  Age d e t e r m i n a t i o n s f o r s e l e c t e d  of  This  age group.  In b o t h  larger  association.  m  ( T a b l e 14 ).  regressions of  f i r a n d swamp f i r  relationships  between h e i g h t and  113  UPFR 140*4-  iao... no... 100... 90... BO... XX X X X  XX ^ x xx  X X  x  x* X  x x  x  x  1  0.  x  25  Graph in  ^  x  x  x X  * \  x  *  X X  10.  1  1  15. i . SO. :  • •B-H.  Figure  X  x 1  5»  X  * X  X x  X  1  1  1  S5-  30.  35.  (CM 3  o f A g e v s . D.B.H. o f M a t u r e A b i e s  the Upland F i r A s s o c i a t i o n .  balsamea  1  h  40* 45.  114  UPFR 15.+  X  1E.1  X X X X /  X  ) K  $  9-4-  6.1  3-1  0«  Figure  10«  26.  Linear Abies  15.  Regression balsamea  H  h  SO* E5« 30* •»B'H« (CM)  of Height  i n the Upland  v s . D.B.H. D a t a  35«  for  F i r Association.  40*  45-  115  SWFR 15.+  1S.1  x _  9«  X  2  x  H  !±f  x  X  X  x>  X  X  XX  G.  X  X  XX  3-1  i  1  0.  5.  1  1  1  1  1  1  10.  15.  20.  E5.  30.  35.  •'•B'H* (CM)  Figure  2.7. L i n e a r Abies  Regression balsamea  of Height  v s . D.B.H. D a t a f o r  i n t h e Swamp F i r A s s o c i a t i o n  1  b  40. 45.  116 diameter growth are the same i n both associations, but i n upland f i r stands conditions are more favourable for height growth, and trees of a particular diameter are t a l l e r i n upland f i r stands than i n swamp f i r stands. Mortality among A. balsamea trees i n the upland f i r and swamp f i r associations may be generally compared by considering the relative abundance of standing dead tress i n each.  Although common i n both  associations, standing dead are more abundant i n swamp f i r stands. In these they form an average of 38.5% of the t o t a l stand density, compared with an average of 29.6% i n upland f i r stands.  Standing dead  trees in swamp f i r stands also have a larger basal area, averaging 2 12.0 m /ha, than those in upland f i r stands, whose basal area averages 2 10.0 m /ha.  A graph of the percentages of total stand densities formed  by standing dead trees by diameter class (Fig. 1% ) indicates that i n upland f i r stands 80% or more of a l l stems under 10 cm i n diameter are standing dead, whereas i n swamp f i r stands these diameter classes have relatively low percentages of standing dead.  Trees greater than 15 cm  in diameter, however, are composed of more standing dead i n swamp f i r stands than i n upland f i r stands. Mortality, then, i s high among small trees i n upland f i r stands, probably because of competition with t a l l e r trees for l i g h t .  Since tree densities are less dense i n swamp  f i r stands, competition would not be as severe, and mortality among small trees i s lower. More mature trees, however, are thinned out to a greater extent i n swamp f i r stands possibly because edaphic conditions here do not support volumes as great as those on upland f i r sites. In upland f i r stands, therefore, trees which survive competition to reach  117  90  0 .1  —  —  5  10  15  20  Stem Diameter  Figure 28  25  30  (cm)  D i s t r i b u t i o n of Standing Dead Abies balsamea among Stem Diameter Classes i n the Upland F i r and Swamp F i r Associations.  i  35  118  canopy height seem to have better chances of survival than those i n swamp f i r stands. The above results indicate that habitat conditions i n upland f i r stands are generally more favourable for those of swamp f i r stands.  A. balsamea  trees than are  Upland f i r sites support a greater tree  volume, indicated by higher densities, higher basal area and lower mortality, than the swamp f i r stands.  Trees i n swamp f i r stands also  tend to be smaller in height and D.B.H. than-those i n upland f i r stands. These differences i n productivity between the two associations are probably controlled by edaphic factors.  The organic soils of swamp f i r  stands are typically very wet and thus probably are poorly aerated. This may be unfavourable for the growth of A.  balsamea,  although  definite statements to this effect would have to be preceded by an analysis of both species' tolerance l i m i t s and the actual oxygen content of the s o i l s . 2. Picea Picea  mariana  mariana  (black spruce)  trees occasionally are found i n the swamp f i r  association, but are common only i n the black spruce association, where they are dominant.  Seedlings of this species vary i n density here from  100 to 7,400 stems/ha i n these stands, and average 2,400 stems/ha. Actual regeneration of P.  mariana  i s probably greater, however, since  vegetative reproduction by layering i s very common. Densities of P.  mariana  i n the shrub layers are very high.  Individuals of low shrub height (.3 m to 1.8 m) have an average density of 4,200 stems/ha and those of high shrub height (1.8 m - 3.5 m) average  119  6,827 stems/ha (Table 1* ). Very few trees exceed 3.5 m to be classed in the tree strata, because exposure to strong winds and winter storms has a pruning effect on leader growth.  The high densities of this  species may be related to the prevalence of layering as a means of reproduction.  Individuals arising i n this way might, as a result of  attachment to the present, be able to survive crowded conditions better than seedlings. Although densities of P. volumes are low.  mariana  are high i n these stands,  The average height i s 2.7 m, and because stem 2  diameters are very small, t o t a l basal area averages only 13.8 m /ha, in spite of high densities. Although stem diameters of P.  mariana  are consistently small,  a wide range of ages are found, suggesting growth i n a number of cases i s poor. Ages of selected trees average 44.2 years, but range from 24 years to 80 years. 3. Picea  glauca  Piaea  glauca  (white spruce)  occurs i n both upland f i r and swamp f i r stands,  but i s not abundant i n either.  Seedlings are scarce, possibly because  of poor seed sources as well as poor light conditions.  In upland f i r  stands seedlings average only 105 stems/ha, and i n swamp f i r stands 337 stems/ha.  Densities may be higher i n swamp f i r stands because mature l,  trees are more abundant and form a larger seed source than i n upland f i r stands. Similarly, and perhaps for the same reasons as above, P.  glauca  saplings are rather few i n upland f i r stands. Densities here average  120 only 7 stems/ha compared with an average of 77 stems/ha i n swamp f i r stands. As previously noted, mature P. glauca  trees are more abundant  in swamp f i r stands, having an average density of 75 stems/ha and an 2 average basal area of 2.6 m /ha. In upland f i r stands, P. glauca may be unable to compete with A. balsamea as young trees; consequently 2 mature trees average only 11 stems/ha i n density and 0.6 m /ha i n basal area. Because so few P. glauca  trees were found i n the associations,  few age data are available for this species. 4. Betula  Betula  papyrifera  papyrifera  (white birch)  i s usually dominant i n successional forest  communities on the Plateau, but i s a r e l a t i v e l y minor component of mature forests.  As a mature tree, the species i s most abundant i n  upland f i r forests, scarce in swamp f i r forests, and very rare on black spruce sites. Seedlings are most common i n upland f i r stands, where densities average 1,360 stems/ha.  Since B. papyrifera  i s generally considered  intolerant of shade, (Oosting and Reid, 1944), the more open stands of the swamp f i r association would seem to be more favourable for seedling establishment.  They are less abundant here than i n upland f i r stands,  however, averaging 702 stems/lia. mature B. papyrifera  This may be a result of a scarcity of  i n swamp f i r stands, or unfavourable seedbed  conditions, as suggested above for Abies balsamea seedlings. Although densities of B. papyrifera  seedlings are lower than  those of A. balsamea,  B. papyrifera  saplings are more abundant. In  upland f i r stands these average 355 stems/ha, and i n swamp f i r stands average 260 stems/ha. These saplings are usually found beneath canopy openings created by a windfall or other localized disturbance. A. balsamea  outnumber B. papyrifeva  more rapid growth of B. papyrifeva  as seedlings in these areas, but the allows them to be classed as saplings  soon after the opening has been created. In the tree layers of upland f i r stands, B. papyvifeva  has an 2 average density of 33 stems/ha and an average basal area of 1.2 m /ha. Trees of this species are much less abundant i n swamp f i r stands, averaging only 5 stems/ha, with an average basal area of only 2 0.1 m /ha, indicating swamp f i r sites are less favourable for mature B. papyrifeva  than are upland f i r sites.  Swamp f i r sites are probably  less favourable because of periodic flooding of the s o i l s , although the certainty of this could not be established without further study. Standing dead B. papyrifera  trees are more than twice as abundant as  l i v e trees of this species, averaging 67.5 stems/ha i n upland f i r stands.  A number of these were perhaps k i l l e d by disease in the past,  while others were possibly individuals that developed i n windfall areas u n t i l overtopped by A. balsamea.  The frequent occurrence of windfalls  in upland f i r stands may explain why B. papyrifera  i s able to maintain  i t s e l f here. 5. Discussion Advance growth as produced by Abies balsamea i n the upland f i r i  and swamp f i r associations i s common in forests throughout the species'  .122 range (Bakuzis, 1965). balsamea  C o l l i n s (1953) reported an abundance of A.  seedlings i n f o r e s t s on the Plateau, and Candy (1951) gave an  average" density of 2,970/acre (7,335/ha) f o r ' s e e d l i n g s i n Cape Breton, which i s w i t h i n the range of those noted i n t h i s study. B i l l i n g s (1951) reported that A. balsamea  Oosting and  seedlings i n f o r e s t s of the 2  northern Appalachians s i m i l a r l y average 2.7/100 m  (13,750/ha).  The high m o r t a l i t y among these seedlings suggested e a r l i e r f o r upland f i r stands i s also found i n other areas.  Oosting and Reid (1944)  reported that i n northwestern Maine F o r e s t s , 60% to 90% of a l l A., balsamea  seedlings d i e w i t h i n the f i r s t two years of l i f e .  Other  authors i n d i r e c t l y i n d i c a t e s i m i l a r c o n d i t i o n s , noting higher  seedlings  but very low d e n s i t i e s of i n shrub l a y e r s ( B u e l l & N i e r i n g , 1957). Opinions vary as to what the major causes of these high mortality rates.  Zon (1914) believed A. balsamea  could grow i n dense  shade as a young seedling, but i n l a t e r years required more l i g h t . Others (Cooper, 1913; Hutchinson, 1918; Oosting and Reid, 1944) Believed A. balsamea  to be generally shade i n t o l e r a n t .  This may e x p l a i n  ppor seedling s u r v i v a l i n upland f i r stands, since most of these have closed canopies and consequently low l i g h t i n t e n s i t i e s at levels.  ground  Place (1955) suggested that on wet s i t e s , A.. balsamea  are often smothered by rapidly-growing  seedlings  species of sphagnum mosses.  Smothering and shading by dense growths of ferns and low shrubs were also implicated as causes of poor seedling growth (Place, 1952). These f a c t o r s may account f o r low seedling d e n s i t i e s i n swamp f i r stands on the Plateau.  Sphagnum mosses are abundant here, and d e n s i t i e s of the  f e r n Osmunda einnamomea are u s u a l l y high.  Place (1965) b e l i e v e d that  123 on well-drained s i t e s , drought i s the major cause of seedling mortality in the f i r s t season, and additional losses may occur during winter from smothering by heavy accumulations of ice and snow. On the Plateau, drought may be an additional cause of seedling deaths. The distribution of summer precipitation on the Plateau i n both 1970 and 1971 was unevenly distributed, and during periods of July, l i t t l e rain was received. During these periods, seedlings whose roots had not extended below the l i t t e r and upper humus layers to more moist s o i l may have been k i l l e d . Mature A. balsamea  trees i n boreal forests of southeastern  Quebec vary from 565/acre to 625/acre (1395/ha - 1544/ha) (Linteau, 1955), which i s similar to the average i n the upland f i r association on the Plateau (Table 14).  However, tree heights i n the Quebec stands  (56 ft/16.8 m) are greater than those i n Plateau stands. western Newfoundland stands dominated by A. balsamea, 2  Similarly, i n  with t o t a l basal  areas averaging 42.5 m /ha (Damman, 1971), are similar to the average for upland f i r stands on the Plateau, but again the Newfoundland stands are generally t a l l e r , averaging 10;8 m in height. Thus, although t o t a l basal areas and densities i n Quebec and Newfoundland stands are similar to those on the Plateau, timber volumes are probably lower i n the Cape Breton stands. The maximum age of Abies  balsamea  reported i n the present  study (139 yrs.) i s similar to those of other areas.  Linteau (1955)  gave a maximum age of 140 years for A. balsamea stands in southeastern Quebec, and Wilton (1964), reported that mature A. balsamea  i n the  boreal forests of Labrador average 125 years i n age and have a maximum  124 age of 220 years.  Oosting and B i l l i n g s (1951) stated that the l i f e  expectancy of A. balsamea  i n the northern Appalachians i s about 148  years, and Bakuzis (1965) reported that i n even the more favourable parts of i t s range, A. balsamea Abies  balsamea  seldom exceeds 200 years i n age.  i s commercially important, i n many areas, and  damage to stands has received much a t t e n t i o n .  Zon (1914) and Wilton  (1964) believed the species i s c h a r a c t e r i z e d by a shallow r o o t i n g habit making large trees h i g h l y vulnerable to windthrow. Cooper (1913) and Nichols (1918) stated that A. balsamea b r i t t l e , r e s u l t i n g i n extensive damage by breakage.  Zon  (1914),  stems are often  Both types of  damage were commonly found on the Cape Breton Plateau i n the present study.  W i n d f a l l s are common, and stem decay was frequently found,  p a r t i c u l a r l y among l a r g e r trees.  According to Bakuzis (1965), fungal  decay or "heart r o t " i s common among mature A. balsamea,  frequency of  i n f e c t i o n increasing with age such that most trees 100 years of age and over are damaged. Insect i n f e s t a t i o n s , p a r t i c u l a r l y those of the spruce budworm (Choristoneura balsamea  fumiferans)  stands.  are an a d d i t i o n a l cause of damage i n A.  Although no recent spruce budworm damage was found i n  t h i s study, i n f e s t a t i o n i n the past has been reported. and Cuming (1966)  Reeks (1953)  reported that l a r g e areas of forest i n the Cape  Breton Highlands N a t i o n a l Pau.k and adjacent areas suffered severe spruce budworm d e f o l i a t i o n . the Plateau.  Damage was apparently most extensive on  Spruce budworm populations remained l a r g e f o r about three  years u n t i l a sharp d e c l i n e was reported i n 1956  (Forbes, et al. , 1956).  Although no d e f o l i a t i o n has been reported since that time, according to  125 B a s k e r v i l l e (1950), Abies  balsamea  stands damaged by spruce budworm are  more susceptible to the fungal i n f e c t i o n s that produce "heart r o t " and "top r o t " . This might account f o r the high frequency of t h i s type of damage among A. balsamea  on the Plateau.  Reproduction of Betula balsamea  papyrifera  i n f o r e s t s dominated by A.  i s described as poor by many authors (Cooper, 1913; C o l l i n s ,  1951; Oosting and Reid, 1944; N i c h o l s , 1918; W i l t o n , 1964).  The major  reason given i s that the species requires an abundance of l i g h t f o r seedling success. papyrifera  This may explain low seedling d e n s i t i e s f o r B.  on the Plateau. As noted e a r l i e r , mature B.  papyrifera  trees are frequently encountered on the Plateau, but d e n s i t i e s are low. Fernow (1912) estimated that i n northern Cape Breton B.  papyrifera  formed only 3% of the f o r e s t volume, and C o l l i n s noted that about 14% of the Plateau f o r e s t s were made up of a combination of B. Picea  glauca,  and Sorbus  americana.  these low d e n s i t i e s of B. papyrifera  According to McDonald (1958),  on the Plateau are a r e s u l t of  severe depletions by a disease known as 'birch dieback'. regions, however, B. papyrifera  In other  i s s i m i l a r l y a frequent, but minor  component of f o r e s t s dominated by A. balsamea. papyrifera  papyrifera,  In Newfoundland B.  has a high frequency but low coverage i n balsam f i r - white  b i r c h f o r e s t s (Damman, 1964), and i n Labrador, the species forms no more than 1% of the t o t a l tree coverage i n s i m i l a r forest types (Wilton, 1964).  Linteau (1955) found B. papyrifera  was f a i r l y common i n young  f i r stands, but reduced to scattered i n d i v i d u a l s i n many o l d e r stands. S i m i l a r l y , LaRoi (1967) reported that B. papyrifera  was present i n  every boreal white-spruce balsam f i r stand examined southeast of Great  126 Slave Lake, but indicated that t o t a l basal areas f o r the species were generally low.  I t appears, then, that the frequent but low-density  presence of B. papyrifera  among upland f i r stands on the Plateau i s not  unusual f o r A. balsamea-dominated Poor reproduction  of Piaea  forests. glauca  i n Abies  balsamea  forests,  as noted i n the present study, has been reported by several w r i t e r s . Cooper (1913) suggested that P. glauca  seedlings are shade i n t o l e r a n t ,  and on I s l e Royale were thus l a r g e l y confined to canopy openings created by w i n d f a l l s . P. glauca  Nichols (1918) reported a s i m i l a r s i t u a t i o n f o r  seedlings i n the Cape Breton Plateau f o r e s t s , and i n  Labrador f o r e s t s , although seed sources f o r Picea  glauca  seem to be  adequate, germination i s poor and seedlings of t h i s species form l e s s than 1% of a l l advance growth (Wilton, 1964). In comparing of seedling growth on various types of seedbeds i n New Brunswick, Place (1955) found that P. glauca  seedlings i n i t i a l l y  had a slower rate of root growth than d i d A. balsamea glauca  seedlings.  P.  seedlings would thus have more d i f f i c u l t y e s t a b l i s h i n g themselves  on t h i c k l i t t e r layers before they were k i l l e d by drought. Fernow (1912) and Nichols (1918) both considered mature P. glauca  trees to be common i n Cape Breton Plateau f o r e s t s , Fernow  estimating the volume of species formed from 15% to 25% of northern Cape Breton f o r e s t s .  C o l l i n s (1951), however, indicated P. glauca  l e s s abundant on the Plateau. In Labrador, P. glauca  trees are  trees form l e s s  than 5% of the f o r e s t volume (Wilton, 1964), and i n the balsam f i r - w h i t e b i r c h f o r e s t s of Central Newfoundland (Damman, 1964), P. glauca have both low coverage and frequency.  trees  In a d d i t i o n , L a R o i s (1967) 1  127  survey of boreal forests indicated that except for southeastern Newfoundland, Picea  glauca  occurred i n . a l l stands, but i n stands east  of Gaspe, had low basal areas resembling those of B. papyrifera.  Low  densities of this species i n upland f i r forests on the Plateau, therefore, i s not unusual for boreal forests i n eastern Canada. As noted above, Picea mariana  on the Cape Breton Plateau  reproduces mostly by layering. Several writers (Damman, 1964; Wilton, 1964, Vincent, 1965) contend that this type of vegetative reproduction, is prevalent among P. mariana  growing i n wet habitats. In comparing  trees formed by layering with those developed from seedlings, Wilton noted that those of vegetative origin usually have curved trunks, sometimes described as "butt sweep". This may explain the peculiar growth form that i s characteristic of most P. mariana  trees growing i n  depressions. On the Cape Breton Plateau, P. mariana on sites dominated by Abies balsamea.  trees were rarely found  Although Nichols (1918)  commented that P. mariana was l o c a l l y an important component of A. balsamea  forests on the Plateau, Collins (1951) spoke of the species  only as a dominant of a separate community type. mariana  i s a frequent although minor component of balsam-fir-white birch  forests (Damman, 1964), and i n Labrador, P. mariana A.  In Newfoundland P.  balsamea  i s as abundant as  on poor sites, sdldom occurs i n mesic.  Productivity among forests on the Plateau i s lowest i n black spruce stands.  Although edaphic factors may p a r t i a l l y account for t h i s ,  growth of P. mariana  trees, particularly i n exposed low-lying stands  near bogs, i s also discouraged by ice and snow blasting i n winter (Nichols, 1918).  128a The appear  3.5  average of  those  and L a b r a d o r ,  f t  (11.4  m)  communities  soils  morphologically  were p o o r e r  apparently similar  along  1964),  on t h e P l a t e a u habitats i n  i n t h e Cape B r e t o n  and W i l t o n ' s  indicate  (1964)  soils  photographs  stand heights a r e greater  C o m p a r i s o n s made i n a n e a r l i e r black spruce  stands  i n Newfoundland  section  on t h e P l a t e a u and indicated  t h e Cape This  and c a l c i u m .  fordifferences  i n growth  i n t h e two a r e a s .  addition,  Newfoundland  and L a b r a d o r  as s e v e r e as those  stands  t h e edges o f bogs i n Newfoundland  potassium  account  i c e storms  develop  i n exchangeable  partially  and  stands  stands  few t r e e s  i n Labrador  beneath  similar  whereas  (Damman,  i n Cape B r e t o n .  between peat  soils  f o r growth than  m, b l a c k s p r u c e  38  similar  than  on which b l a c k s p r u c e  to be p o o r e r  Newfoundland reach  sites  Breton  might In  s t a n d s may n o t b e s u b j e c t e d t o w i n d  on t h e P l a t e a u .  128b  VII.  Previous associations, Plateau, area.  The  chapters Plateau and  of  Cape The  ridges,  than  those  between  three forest  spruce  fairly  the  results  on  each  the the  of  these  among t h e  three  the  t h e P l a t e a u and  on  climate of  from  relationships  have  associations  of  low  ridges.  have s o i l s  Low-lying  black  of  s u c c e s s i o n a l s t a t u s of  associations,  those  i n Lowland  common, and  of  the  Black  distinct.  The  three, occurs  spruce  stands  on  may  upland  the  also  fairly develop  nutritionally  poorer  on  the P l a t e a u o f t e n have poorer horizons.  develop.  often occurs  On The  these  black spruce  i n exposed  as  those  bordering  thick,  and  underlying mineral horizons are poorly developed.  fir  and  b l a c k spruce  stands  are  compared  found  f o r poor  with upland  this  is  very  common, and  beneath  association  organic layers  less  found  such  tree  and  swamp f i r a n d  The  are  soils  areas  the  bogs.  stands  of  sites,  drainage,  peat  fir  on  f i r stands.  t h i c k peat  associations  the P l a t e a u are developed  w h i c h a r e more s t o n y a n d  upland areas  on  edaphically  t h e most w i d e s p r e a d  beneath  here  the  ecological  t o p o g r a p h i c a l l y and  soils  but  soils  forest  s p e c i e s performances  some o f  forests  of  Breton.  association,  well-drained  of  tree  descriptions  characterization  utilizes  associations,  s i t e s which are fir  and  a partial  in a discussion  relationships  areas  on  as  soils,  following  forest  DISCUSSION  c h a p t e r s have p r e s e n t e d  forest  as w e l l  FINAL  type  growth  f i r stands.  are Swamp  i n swamp Soil  129  chemical analyses made i n the present studies i n d i c a t e d that aside from L.F.H. horizons beneath black spruce stands being poorer i n exchangeable cations and t o t a l nitrogen, s o i l s beneath the three associations are, on the average, s i m i l a r i n terms of exchangeable sodium, calcium, magnesium, and potassium, t o t a l n i t r o g e n , phosphorus, and pH. Nevertheless, the swamp f i r and black spruce s o i l s i n depressions have t h i c k organic horizons that appear to be poorlydrained and consequently water-saturated f o r most of the growing season. Poorly-drained organic s o i l s such as these are often poor i n a v a i l a b l e nitrogen and are l i k e l y to be poorly aerated, a c o n d i t i o n which i n h i b i t s root metabolism (Lutz and Chandler, 1946; Wilde, 1946).  The  swamp f i r and black spruce s o i l s are, i n these respects, l i k e l y to be l e s s favourable f o r growth than those beneath upland f i r stands. Although s o i l s beneath swamp f i r stands are s i m i l a r i n many respects to those of black spruce stands i n l o w - l y i n g areas, swamp f i r stands are s t r u c t u r a l l y more s i m i l a r to upland f i r stands. d e f i n i t e tree l a y e r s dominated by Abies  balsamea,  Both have  and i n both types,  shrub l a y e r s are more poorly developed while herb l a y e r s are b e t t e r developed  only i n more sheltered areas.  S o i l s here again are poorly  drained and have t h i c k organic horizons, but u s u a l l y have w e l l developed Ae and B horizons as w e l l , i n d i c a t i n g the occurrence of v e r t i c a l seepage.  I,  The s i t e s on which the black spruce a s s o c i a t i o n develops are the l e a s t favourable, as i n d i c a t e d by stand p r o d u c t i v i t y . mariana  Picea  i s ' the only tree species which can grow i n abundance i n the  poorly drained areas surrounding bogs and on n u t r i t i o n a l l y poor s o i l s  130  on r i d g e s .  Growth i s v e r y poor on these s i t e s ; stands a v e r a g i n g 44  years o f age have a mean h e i g h t o f l e s s than t h r e e metres.  Although  stem d e n s i t i e s of t r e e s i n these stands a r e h i g h (Avg. 6,827/ha), stem diameters r a r e l y exceed (13.8  10 cm.,  and  t o t a l b a s a l areas are  low  m /ha). 2  Swamp f i r s i t e s are more f a v o u r a b l e than those of b l a c k spruce stands, but are l e s s p r o d u c t i v e than upland f i r s i t e s . balsamea,  Trees of  Abies  the dominant s p e c i e s i n both a s s o c i a t i o n s , have a lower  average d e n s i t y , t o t a l b a s a l a r e a , and h e i g h t i n swamp f i r stands than those i n upland f i r stands. fir  In a d d i t i o n , s t a n d i n g dead t r e e s i n swamp  stands a r e , on the average, more numerous and  areas than those i n upland f i r s t a n d s .  form h i g h e r t o t a l b a s a l  Thus, the s i t e s on which the  upland f i r a s s o c i a t i o n develops a r e the most f a v o u r a b l e . A l t h o u g h the exposure o f b l a c k spruce stands to s e v e r e wind storms p r o b a b l y accounts i n p a r t f o r the poor growth t h e r e , edaphic c o n d i t i o n s a r e c o n s i d e r e d to be p a r t l y  responsible.  In the upland f i r a s s o c i a t i o n , the abundance of Abies s e e d l i n g s and  the wide age range among t r e e s i n d i c a t e s t h a t  balsamea  these  f o r e s t s are i n a s t a b l e c l i m a x s t a t e .  Very l o c a l i z e d d i s t u r b a n c e s ,  r e s u l t i n g i n the removal  t r e e s , r e l e a s e the abundant A.  balsamea  s e e d l i n g s from s u p p r e s s i o n by shading, and t h i s s p e c i e s i s  predominant balsamea  of o n l y a few  i n the new  growth'.  on the P l a t e a u was  N i c h o l s (1918) b e l i e v e d  t h a t A.  p a r t i c u l a r l y s u s c e p t i b l e to w i n d f a l l , owing  to i t s s h a l l o w r o o t i n g h a b i t , and s m a l l d i s t u r b e d a r e a s such as were c o n s i d e r e d common.  this  He a l s o noted the presence of l a r g e r a r e a s ,  however, such as the s u c c e s s i o n a l stands examined i n t h i s study.  In  131  these,  light  c o n d i t i o n s are markedly  establishment  o f t e n dominate  balsamea for  will  individuals. created  by  The  on  spruce and  considered the  associations these  may  i n stable  are  dominated  by  papyrifera  Abies  balsamea,  trees, to  those  the presence  1918).  and  the  the  possibly  presence  of  and  i n the Lowlands  forest  Picea  strata  Acer  The  t r e e s on type  soils,  of  edaphic these  growth climax  are ranges  forests forests  on  and  Betula  floristically  types  differ,  t r e e s i n the  however,  Lowland  According  successional stage  i t forms an  are  reportedly are  the P l a t e a u .  is a  the  tree species.  are  two  rubrum  to  glauca  that  of  t h e w i d e age  second  forests  favourable  swamp f i r a n d  Both  climatic  scattered  Nichols,  poor  the  dominant  These lowland  strobus  w h i l e on  few  climax  related  climaxes.  o f Cape B r e t o n ,  n e i t h e r of which occurs.as  soils,  to a  t h e most  again because of  forests,  favourable  competition  frequent  climatic  directly  growth by  have  this  the  occupies  the  edaphic  have u n d e r s t o r y  Pinus  A.  these disturbances,  i n the Plate'au f o r e s t s . of  conditions,  resulting  distinguishing  i n some r e s p e c t s r e s e m b l e (Nichols,  these  i n number  explain  t o be  states,  areas  under  stands.  appear  forests  the Lowland  the P l a t e a u  by  of  f i r association  p r o d u c t i o n of advance  which,  similar  storms,  the upland  t o be  In found  wind  that  s e e d l i n g s i s more  i n the  t r e e s are reduced  Vegetation characteristics  factors,  and  and  occurrence  extent  E v e n t u a l l y , however,  the P l a t e a u , i t i s considered  region. black  B. papyrifera.,  trees i n older  Since  papyrifera  vegetation.  repeated  localized  B. papyrifera  sites  t h e new  overtop  to the  s a p l i n g s grow w e l l  B. papyrifera  light,  Betula  growth of  B. papyrifera  successful. and  and  improved  edaphic  climax.  to  on On  132  richer soils, climax,  s u c c e s s i o n proceeds to a predominantly deciduous  i n which Abies  p o s i t i o n , and  balsamea  Betula  dominant.  A l l of these  Acer  rubrum,  t r e e s occupy a r e l a t i v e l y minor  t r e e s of s p e c i e s such as Fagus  saccharum,  lutea  (B.  grandifolia,  alleghaniensis),  and Acer  Acer rubrum  t h e r e as a low  complete absence of these  shrub.  Nichols believed  areas,  suggesting  t h a t on  P l a t e a u , minimum temperatures a r e lower, maximums a r e h i g h e r , p r e c i p i t a t i o n i s g r e a t e r than i n Lowland  between the two  areas,  do not  they do  the  and  areas.  While c l i m a t i c measurements of the present 1971  the  s p e c i e s among P l a t e a u c o u l d be a t t r i b u t e d to  d i f f e r e n c e s i n c l i m a t e between the two  and  are  s p e c i e s are absent on the P l a t e a u , except f o r  which o c c u r s  summers of 1970  forest  study made i n the  indicate differences in precipitation suggest t h a t temperatures are g e n e r a l l y  s e v e r a l degrees lower on the P l a t e a u , e s p e c i a l l y i n e a r l y summer. General  observations  o p i n i o n t h a t low Lowlands.  made d u r i n g t h i s time a l s o c o i n c i d e w i t h  fogs a r e much more f r e q u e n t  R e s u l t s of the present  study,  Lowlands are determined by  climate.  on the P l a t e a u than i n the  then,  c o n c l u s i o n t h a t d i f f e r e n c e s between c l i m a x  Nichol's  support  Nichol's  f o r e s t s on the P l a t e a u  and  133  VIII.  SUMMARY  Phytosociological methods were used in the present study to sample and describe major forest communities on the Cape Breton Plateau. These forests were grouped into three associations, a l l of which are f l o r i s t i c a l l y , topographically, and edaphically d i s t i n c t .  The most  common of these forest types i s the upland f i r or Abies balsamea Dryopteris  spinulosa  - Hylooomium  umbratum  association.  -  This type  occurs on the most favourable sites found on the Plateau, on low ridges, and i s considered to be the climatic climax of the region.  In poorly-  drained sheltered areas, a f a i r l y uncommon association, the swamp f i r or Abies balsamea - Osmunda cinnamomea - Sphagnum capillaceum develops.  association  Soils beneath these stands have thick organic horizons, and  the forest type i s an edaphic climax. spruce or Picea mariana  - Pleurozium  The third association, the black schreberi  association, occurs  primarily on wet organic soils as well, but usually in more exposed areas, such as those near open peat bogs.  This association i s also  found, although less frequently, on thin,^rocky soils on low ridges. Upland f i r stands usually have closed tree canopies, in which Abies  balsamea  i s dominant, with average coverages of 41% for the A^  layer, and 32% for the A^ layer.  Trees of Betula  papyrifera  present as well, but with much lower coverages and densities.  are usually Shrub  layers are poorly developed in these stands, total averages averaging only about 5%. Although several shrub species are f a i r l y common, these  134  layers are comprised primarily of saplings of Abies balsamea and Betula Poor development of the shrub layers i s probably due to  papyrifera.  the fact that understory levels are usually shaded.  Windfalls are  common i n these stands, and where these create openings i n the canopy, shrubs and saplings of tree species are more abundant. The herb and dwarf shrub layer of the upland f i r association i s much better developed, and has an average coverage of 81%. Dryopteris  spinulosa,  with an average coverage of 26%, i s the most  abundant species of the layer. Abies  balsamea  borealis,  Cornus canadensis,  seedlings, Coptis  and Trientalis  borealis  trifolia,  Aster  Oxalis  montana,  acuminatus,  are also abundant.  Clintonia  In addition to  these, a number of species distinguish the upland association from the other two types, by being common i n this type only. Dryopteris  Phegopteris,  Moneses  uniflora.  Athyrium  Filix-femina,  These are:  Osmunda claytoniana,  and  Bryophytes are f a i r l y abundant i n upland f i r stands, where ground surfaces are not heavily shaded.  The Dh layer averages 55% i n  coverage, and i s largely composed of Hylocomium umbratum and  Pleurozium  Other less abundant but frequently occurring species are  schreberi.  Sphagnum capillaceum, cristacastrensis,  Dicranum  magus, Rhytidiadelphus  and Polytrichum  commune.  decayed wood include Bazzania\, trilobata  loreus,  Ptilium  Bryophytes common on  and Dicranum  fuscescens.  Swamp f i r stands have more open tree canopies, again dominated by A. balsamea.  Picea  glauca  trees are also frequently found, but have  low coverages. Unlike upland f i r stands, the swamp f i r stands have poorly developed A layers. q  These average only 17% i n coverage, and as  135  a result, shrub layers below are only p a r t i a l l y shaded.  These are thus  better developed than those of upland f i r stands, with respective coverages of 13% and 40% for the layers Abies balsamea Amelanchier  bartramiana,  and B^ layers.  In both of these  saplings are the most abundant, although Sorbus  decora,  and Nemopanthus  mucronata  are  also common. Favourable light conditions i n swamp f i r stands also allow the C layer to be f a i r l y well developed.  This layer has an average  coverage of 92%, and i s dominated by Osmunda cinnamomea,  covering an  0. cinnamomea an important distinguishing species for  average of 42%.  the association, being common i n none of the other forest types. species abundant i n the C layer of this association are: spinulosa,  Cornus  canadensis,  and Coptis  Other  Dryopteris  trifolia.  Among bryophytes of the Dh layer i n this association, Sphagnum i s the most abundant, with an average coverage of 28%.  capillaceum  Other common species include Pleurozium and Bazzania  trilobata.  Hylocomium  umbratum,  Common bryophytes growing on decayed wood i n  this type include Rhytidiadelphus Dicranum  schreberi,  loreus,  Ptilidium  ciliare,  and  fuscescens.  The black spruce association structurally d i f f e r s from the two other Plateau forest types by lacking a definite tree canopy. mariana  Picea  individuals, the most) abundant species i n a l l except the ;  bryophyte strata, instead form dense thickets of about three metres i n height.  Coverages are high, averaging 55% i n the B^ layer, and 41% i n  the B^ lay'er.  A number of shrub species are abundant i n spaces between  the P. mariana  thickets; these include Nemopanthus  mucronata,  136 Rhododendron and  Kalmia  canadense,  Viburnum  augustifolia.  Abies  cassinoides, balsamea  Amelanchier  saplings  are  bartramiana, frequently  found  i n t h e s e s t a n d s , but a r e never abundant h e r e . . The dense development of t h e s e shrub l a y e r s d i s c o u r a g e s t h e growth o f herb and dwarf shrub s p e c i e s below.  The C l a y e r has  an  average coverage of 48%, and i s p r e d o m i n a n t l y composed o f shrub s e e d l i n g s and P. mariana species and  i n c l u d e Cornus  Gaultheria  advance growth. canadensis,  Constant herb and dwarf  Clintonia borealis,  Coptis  shrub  trifolia,  hispidula.  B r y o p h y t e s i n t h e s e s t a n d s a r e not as s e r i o u s l y a f f e c t e d by s h a d i n g , and those growing on humus have an average coverage of 77%. The most abundant of t h e s e s p e c i e s a r e Pleurozium Sphagnum  capillaceum.  trilobata,  species.  Dicranum  Two  schreberi  These a r e u s u a l l y accompanied by majus,  Hylocomium  splendens,  and  and Bazzania  several  Cladonia  c o n s t a n t s p e c i e s form t h e D dw l a y e r of t h i s a s s o c i a t i o n ;  they are P t i l i d i u m c i l i a r e  and  Dicranum  fuscescens.  I n a d d i t i o n t o s a m p l i n g s t a n d s o f the t h r e e f o r e s t a s s o c i a t i o n s , t h r e e s u c c e s s i o n a l s t a n d s on upland f i r s i t e s were examined.  In a l l  t h r e e of these s t a n d s , the t r e e c a n o p i e s have been e s s e n t i a l l y d e s t r o y e d , p o s s i b l y by l o c a l i z e d wind storms.  The dominant v e g e t a t i o n  i n t h e s e a r e a s i s composed of young s a p l i n g s .  I n two of t h e s t a n d s  examined, Abies  balsamea  and B e t u l a p a p y r i f e r a s a p l i n g s were b o t h  abundant, w h i l e i n the t h i r d , few A. balsamea shrub l a y e r s c o n s i s t e d m o s t l y o f B. papyrifera.  were p r e s e n t , and  the  I t appears, then, that  a l t h o u g h B\ p a p y r i f e r a t r e e s a r e o n l y s c a t t e r e d i n mature s t a n d s , the s p e c i e s i s f a r more abundant i n s u c c e s s i o n a l s t a g e s .  Often i t i s  137 dominant  i n disturbed  areas,  until  A l t h o u g h many a u t h o r s boreal,  i n the forest  (1956, 1972), transitional question  Acadian  o f whether  which  Although  The  number  of species  forest  morphological  soils  features  beneath upland  upper  loam,  described  (Wilton,  black  and t r e e  spruce  species  types  are also  o f southern  types f i r  composition.  richer,  especially listed  as  common o n t h e P l a t e a u .  f o r e s t s and t h o s e the Plateau  by  1964).  and upland  a l l b u t a few o f t h e s p e c i e s  although  of the Plateau of p r o f i l e s  f i r stands  and a r e o f t e n  B horizon, Soils  these  comparisons  i n each a r e a , f o r e s t  i n the Boreal  forests contain  regions,  were sampled  suggest  they  should  a be  swamp  fairly  f i r soils  a r e o v e r l a i n by t h i c k peat  groupings.  a r e moderately well drained,  but are concentrated  below  by a s s o c i a t i o n ,  four broad  L - F - H (10 cm) u n d e r l a i n b y Ae a n d B h o r i z o n s . sandy  of the  t o answer t h e  1955) a n d i n L a b r a d o r  forest  characteristic  part  f o r e s t s i n Newfoundland  the Plateau  indicate that  a n d Rowe  boreal.  The  thin  (1937)  associations are f l o r i s t i c a l l y  between  f o r e s t s as  forests are boreal,  i n d i c a t e d that  species,  balsamea.  the Plateau  In an attempt  t o t h e Cape B r e t o n  i n t h e more n o r t h e r n  Region  A.  are considered  i n terms o f physiognomy  similarities  Soils  (Linteau,  are similar  Forest  and  and b o r e a l  generally  the Plateau  considered  Region.  by  of Halliday  or not the Plateau  terms o f herbaceous  common  are  Forest  (1964) i n Q u e b e c  associations,  in  classifications  these  These comparisons exist  have c l a s s e d  the f o r e s t s of the area  w e r e made b e t w e e n Damman  overtopped  stony.  Roots  and have a  The m i n e r a l extend  soils  into the  i n t h e L-F-H h o r i z o n . a l s o have Ae and B h o r i z o n s , b u t  l a y e r s , averaging  35 cm. i n t h i c k n e s s .  138 Again most of the roots are found i n the organic horizon.  This peat  layer i s u s u a l l y wet, and seepage i s often found at the Ae horizon. Black spruce stands are developed  on two s o i l types.  Those i n  low l y i n g areas have s o i l s characterized by t h i c k peat horizons averaging 56 cm i n thickness, underlain by a poorly developed  B horizon.  Roots are r a r e l y found below the organic horizon i n these s o i l s .  Soils  beneath black spruce stands on ridges have thinner organic horizons, developed  over Ae and B horizons.  The mineral s o i l s here are stony, and  very few roots are found i n the B horizon. Chemical a n a l y s i s i n d i c a t e the f o r e s t s o i l s on the Plateau are n u t r i t i o n a l l y poor.  Few d i f f e r e n c e s e x i s t , however, among r e s u l t s  obtained for the s o i l s beneath the three types.  T o t a l nitrogen i n  organic horizons has a concentration of about 2%, but i n mineral horizons i s g e n e r a l l y l e s s than 0.1%. Carbon-nitrogen  r a t i o s are f a i r l y  high, averages ranging from about 25 to nearly 60, suggesting that nitrogen a v a i l a b i l i t y i s low.  The L-F-H of black spruce s o i l s on  ridges i s e s p e c i a l l y poor i n t h i s respect, having a t o t a l nitrogen concentration of only 0.09%, and a carbon-nitrogen r a t i o of 41. Concentrations of exchangeable cations are generally low i n a l l of the Plateau forest s o i l s .  These are highest i n the L-F-H horizons,  where concentrations of calcium and magnesium are about 1.5 meq/100 g. Sodium l e v e l s here are about 0.1 meq/100 g, and potassium  concentrations  are about 0.2 meq/100 g. Again black spruce s o i l s on ridges are generally poorer, l e v e l s of a l l exchangeable cations i n the L-F-H horizon being only about 0.1 meq/100 g.  In a d d i t i o n , the organic s o i l  of black spruce s o i l s i n depressions have high concentrations of  139 exchangeable magnesium, averaging 3.58 meq/100 g. Otherwise, exchangeable c a t i o n concentrations, are similar,beneath the various a s s o c i a t i o n s . In the mineral horizons of these s o i l s , exchangeable c a t i o n l e v e l s are very low, averages ranging from 0.05 to 0.10 meq/100 g. Cation exchange c a p a c i t i e s are highest i n the L-F-H horizons, at about 100 meq/100 g, averages i n the mineral horizons varying from 10 meq/100 g to 30 meq/100 g. A l l of the Plateau f o r e s t s o i l s are a c i d , pH values being lowest i n the L-F-H horizon, at about 4.5, and i n c r e a s i n g s l i g h t l y with depth, to about 5.0 i n the B and C horizons.  The high a c i d i t y of these  s o i l s i s probably due to the acid nature of the coniferous organic m a t e r i a l , as w e l l as leaching a c t i v i t y . Although analyses i n d i c a t e d the organic s o i l s below swamp f i r and black spruce stands g e n e r a l l y have s i m i l a r concentrations of exchangeable cations as those beneath upland f i r stands, the organic s o i l s are poorly drained, and hence may be poorly aerated.  I f this i s  true, the organic s o i l s might be poor for vegetation development. The f o r e s t s o i l s of the Plateau were b r i e f l y compared with s o i l s beneath s i m i l a r vegetation types i n Quebec described by Linteau (1955) and i n Newfoundland (Damman, 1964, 1971).  Comparisons  indicated that Plateau s o i l p r o f i l e s are generally s i m i l a r t o those i n the other regions, with the exception that the Cape Breton s o i l s generally have t h i c k e r and more acid L-F-H horizons than those i n Quebec. In a d d i t i o n , exchangeable calcium and magnesium l e v e l s are generally higher i n Quebec and Newfoundland s o i l s . General c h a r a c t e r i s t i c s of major tree species on the Plateau  140  were described for each of the three associations.  Abies  balsamea,  the  dominant species of both upland f i r and swamp f i r associations, produces advance growth in both associations, indicating both types are in f a i r l y stable climax states.  Seedlings are more abundant i n upland  f i r stands, where seedbed conditions are more favourable. On swamp f i r sites, thick sphagnum moss layers probably smother  young seedlings.  However, light conditions i n swamp f i r stands are more favourable for survival of seedlings that do establish themselves, and A.  balsamea  saplings are much more abundant here than i n upland f i r stands. In upland f i r stands, seedling mortality i s high, probably because of shading and occasional periods of drought. Upland f i r stands are much more favourable for growth of A. balsamea  trees.  Densities here average 1,390 stems/ha, and t o t a l basal  areas average 41.1 m /ha.  On the other hand, swamp f i r stands have an  average tree density of only 842 stems/ha, and an average t o t a l basal 2 area of 22.9 m /ha.  In addition, trees i n swamp f i r stands are smaller  in diameter and height. Standing dead trees are more abundant i n swamp f i r stands, further indicating conditions are less favourable here for growth of A. balsamea Picea  mariana  where i t i s dominant.  trees than are those i n upland f i r stands. i s common only i n the black spruce association, Reproduction on these sites i s f a i r l y successful,  and i s mostly vegetative, by /layering.  This type of regeneration  produces a low, sweeping growth habit.  Densities i n the shrub layers  are high, averaging from 4,000 to 6,000 stems/ha., and the thickets formed by this species are very dense.  Growth i s very poor, and although  the trees have an average age of about 45 years, few individuals grow  141  more than 3 m i n height or 5 cm i n diameter. Piaea  glauoa  i s most abundant i n swamp f i r stands, whereas i n  upland f i r stands, few seedlings or trees of this species are found. The species may prefer the swamp f i r sites because of more favourable light and moisture conditions.  was rarely found i n black  P. glauca  spruce stands. 'Betula  i s often dominant i n successional stages, but  papyrifeva  i s a minor component of mature stands.  Seedlings are most abundant i n  upland f i r stands, where seed sources are usually present. f i r stands, few B.  papyrifera  trees are found, and seedling densities  of this species are lower than i n upland f i r stands. papyrifera  In swamp  Although B.  saplings are also f a i r l y abundant i n upland f i r stands, trees  of this species are only scattered, and standing dead are twice as abundant as l i v e trees. Although many of these probably died i n competition for light with  A. balsamea,  others were possibly k i l l e d by  the birch dieback disease. Nichols (1918) compared the forests of the Plateau with those of the Lowlands of Cape Breton, and noted that although forests dominated by A.  balsamea  are found i n Lowland areas, they are  successional stages, or edaphic climaxes.  The climatic climax of the  Lowlands i s predominantly deciduous, and i s composed of a number tree species absent on the Plateauj. Nichols (1918) believed this situation i s attributable to climatic differences between the two areas.  Weather  stations were established on the Plateau as part of the present study during the'periods from June to September i n 1970 and 1971. Temperatures measured during this period on the Plateau ranged from 0°C to 31°C i n  142 1970 and from 3°C to 28°C i n 1971.  June was the coldest month i n both  years, maximum temperatures averaging about 20°C and minimum temperatures averaging from 8°C to 10°C.  In J u l y and August, mean  maximums were about the same, but minimums were generally higher, averaging about 12°C.  During t h i s period, maximum and minimum  temperatures at Cheticamp and Ingonish Beach i n the Lowlands were generally two or three degrees lower. D a i l y temperature ranges on the Plateau were highest i n June, averaging 10°C to 12°C.  Average ranges at the Lowland s t a t i o n s during  t h i s month were about 9°C. Wind speeds on the Plateau were s l i g h t l y higher i n June, averaging 13 km/hr i n 1970, with a maximum reading of 28.7 km/hr. Average wind speeds f o r J u l y and August were l e s s than 1 km/hr lower, however. P r e c i p i t a t i o n on the Plateau during the 77-day period i n 1970 t o t a l l e d from 30 cm to 40 cm, and i n 1971, t o t a l l e d from 28 cm to 31 cm over a 44-day period.  P r e c i p i t a t i o n at Cheticamp i n 1970 was lower  than that of the Plateau, but was s i m i l a r at Ingonish Beach. These r e s u l t s , then, support N i c h o l s ' b e l i e f that the Plateau i s s l i g h t l y colder than the Lowland areas, although p r e c i p i t a t i o n does not appear to be d i f f e r e n t i n the two regions. Climate at Buchans, Newfoundland i n 1970 appeared to be generally s i m i l a r to that of the Plateau, although minimum temperatures were s l i g h t l y lower i n June, suggesting that the onset of the growing season i n Newfoundland might be l a t e r than on the Plateau.  143  IX.  CONCLUSIONS  From the p r e s e n t study o f c l i m a t e , and f o r e s t v e g e t a t i o n and s o i l s on the Cape Breton P l a t e a u , the f o l l o w i n g c o n c l u s i o n s a r e formed: 1.  Three major a s s o c i a t i o n s can be r e c o g n i z e d among u n d i s t u r b e d forests.  These a r e the upland  spinulosa  - Hylocomium  f i r o r Abies  -  umbratum a s s o c i a t i o n , the Abies  Osmunda cinnamomea - Sphagnum capillaceum and  balsamea  the b l a c k spruce or Picea  mariana  Dryopteris balsamea  -  or swamp f i r a s s o c i a t i o n ,  - Pleurozium  schreberi  association. 2.  The swamp f i r a s s o c i a t i o n , w h i l e b e i n g a d i s t i n c t floristically  s i m i l a r to both the upland  type, i s  f i r and b l a c k  spruce  a s s o c i a t i o n s , whereas these two a s s o c i a t i o n s have fewer s p e c i e s i n common. 3.  The upland  f i r a s s o c i a t i o n i s i n a s t a b l e c l i m a x s t a t e , and i s  c o n s i d e r e d t o be the c l i m a t i c c l i m a x o f the P l a t e a u .  The swamp f i r  and b l a c k spruce a s s o c i a t i o n s a r e a l s o s t a b l e , and a r e edaphic climaxes. 4.  The upland to  f i r and b l a c k spruce f o r e s t s a r e s i m i l a r i n many r e s p e c t s  c e r t a i n b o r e a l f o r e s t types i n s o u t h e a s t e r n Quebec, c e n t r a l I,  Newfoundland, and Labrador, B o r e a l F o r e s t Region. richer  and s h o u l d be c l a s s e d as p a r t o f the  The Cape B r e t o n f o r e s t s a r e f l o r i s t i c a l l y  than those i n the n e i g h b o u r i n g b o r e a l f o r e s t s , and should be  c l a s s e d as a d i s t i n c t  s e c t i o n w i t h i n the b o r e a l r e g i o n .  144  5.  Forest s o i l s and  on  exchangeable  soils  beneath  poorer  than  generally  organic poor  black spruce  similar  soils,  favourable  7.  of  8.  the Lowlands  poorer  lower  than  temperature  the growing  balsamea  on  Although  nutritionally examined  other  are  sites.  i n the p o o r l y - d r a i n e d swamp f i r s t a n d s b e c a u s e  i s very  ranges  season  i n the Lowlands.  Tree  of  at c o a s t a l  are  probably  Although  on  Lowland  a r e h i g h e r on  i s probably  more  those of tree  growth on  c l i m a x v e g e t a t i o n on  the  mortality  black  spruce  the P l a t e a u related  a r e a s , and  s e v e r a l weeks l a t e r  low  are  in  The on  June,  beginning the P l a t e a u  f o g s a r e more common on  f o r the area  received  i n Lowland  Although  minimum t e m p e r a t u r e s , i n J u n e a r e  i s similar  and  to  the P l a t e a u  the P l a t e a u .  summer p r e c i p i t a t i o n  to  the  that  a r e a s j,  Buchans, Newfoundland precipitation  than  are  poor.  Summer t e m p e r a t u r e s  those  i s developed  trees  Plateau,  and  are  sodium.  i s h i g h e r and  f i r stands.  o f Cape B r e t o n  slightly  than  soils  Productivity  between c l i m a t i c  differences.  of  Abies  i n upland  climatic  daily  be  ridges  f i r association  the o t h e r hand,  Differences that  in total nitrogen,  characteristics  forest  may  the upland  f o r growth o f  are lower on  on  b l a c k s p r u c e and  swamp f i r a s s o c i a t i o n .  sites,  poor  aeration.  on w h i c h  rates  stands  among t h e  beneath  and  c a l c i u m , m a g n e s i u m and  chemical  of n u t r i e n t s  soils  soil  Sites  potassium,  other  Availability  6.  the P l a t e a u are a c i d ,  than  totals  those  are  on  similar  several  degrees  t h e P l a t e a u , summer f o r the  two  areas.  lower  at  temperatures  145  X.  LITERATURE CITED  Bakuzis, E. V. and H. L. Hansen. 1965. Minnesota Press, Minneapolis. 445  Balsam F i r . Univ. of pp.  B a s k e r v i l l e , G. L. 1960. M o r t a l i t y i n immature balsam f i r f o l l o w i n g severe spruce budworm d e f o l i a t i o n . For. Chron. 36: 342-345. Becking, R. W. 1957. The Ziirich-Montpellier school of phytosociology. Bot. Rev. 23: 411-488. Buckman, H. 0. and N. C. Brady. s o i l s . MacMillan Co., N.Y.  1960. The nature and properties of 567 pp.  B u e l l , M. F. and W. A. N i e r i n g . 1957. F i r - s p r u c e - b i r c h f o r e s t s i n northern Minnesota. Ecology 38: 602-610. Buoyoucos, C. J . 1951. A r e c a l i b r a t i o n of the hydrometer method for making mechanical analyses of s o i l s . Agron. J . 43: 434-438. Canada Department of A g r i c u l t u r e . 1970. The system of s o i l c l a s s i f i c a t i o n f o r Canada. Queen's P r i n t e r , Ottawa. 249 pp. Canada Department of Transport. 1964. Temperature normals f o r the A t l a n t i c Provinces. C l i m a t o l o g i c a l Div., M e t r o l . Br., Ottawa. Canada Department of Transport. 1965. P r e c i p i t a t i o n normals for the A t l a n t i c Provinces. C l i m a t o l o g i c a l Div., Metrol. Br., Ottawa. Candy, R. H. 1951. Reproduction on cut-over and burned-over land i n Canada (East of the Rocky Mountains). S i l v . Res. Note For. Br. Can. 92. 224 pp. Cann, D. B., J . I. MacDougall, and D. J . Hilchey. 1963. S o i l survey of Cape Breton I s l a n d , N.S. S o i l Survey Rep. No. 12. Chapman, L. J . and D. M. Brown. 1966.. The climates of Canada f o r a g r i c u l t u r e . Dept. of Fprestry and Rural Development, Ottawa. Canada Land Inventory Rep. No. 3. C o l l i n s , E. H. 1950. An a n a l y t i c a l study of some aspects of the boreal forest i n northern Cape Breton. B.A. (honours) Thesis. Acadia Univ., W o l f v i l l e , N.S. (unpublished). i  . 1951. A study of the boreal forest formation i n northern Cape Breton I s l a n d . M.A. Thesis. Acadia Univ., W o l f v i l l e , N.S. (unpublished).  146 Comeau, P. L. 1971. A study of f i v e raised bogs on the Cape Breton Plateau. M.Sc. Thesis. Acadia Univ., W o l f v i l l e , N.S. (unpublished). Cooper, W. S. 1913. The climax f o r e s t of I s l e Royale, Lake Superior, and i t s development. I . Bot. Gax. 55: 1-44. Crum, H. A., W. C. Steere and L. E. Anderson. 1973. A new l i s t of mosses of North America north of Mexico. B r y o l o g i s t 76: 85-131. Cuming, W. D. 1956. The spruce budworm i n the A t l a n t i c region i n 1955 - Nova S c o t i a . Canada Dept. Agr. For. B i o l . Div. S c i . Serv. Bi-Monthly Prog. Rep. V o l . 12 No. 3. Damman, A. W. H. 1964. Some f o r e s t types of c e n t r a l Newfoundland and t h e i r r e l a t i o n to environmental f a c t o r s . Canada Dept. Forestry. For. Res. Br. C o n t r i b u t i o n No. 596. 62 pp. . 1971. E f f e c t of vegetation changes on the f e r t i l i t y of a Newfoundland forest s i t e . E c o l . Monog. 41: 253-270. Fernald, M. L. 1925. The persistance of plants i n unglaciated areas of boreal North America. Amer. Acad. A r t s & S c i . Mem. 15: 237-342. Fernow, B. E., C. D. White and J . H. Howe. 1912. Forest conditions i n Nova Scotia. Canada Commission of Conservation, Ottawa. Forbes, R. S., W. J . C a r r o l l , G. R. Underwood, and F. G. Cuming. 1956. A t l a n t i c Provinces forest insect survey, in Forest insect and disease survey. Canada Dept. Agr. S c i . Serv. For. B i o l . Div. pp. 7-22. Geiger, R. G. 1965. The climate near the ground. Harvard Univ. Press, Cambridge, Mass. 611 pp. Goldthwaite, J . W. 1924. Physiography of Nova S c o t i a . Canada. Mem. 140 177 pp.  Geol. Surv.  H a l l , I . V. 1949. A paleoecological study of f o r e s t successions i n northeastern Cape Breton I . as determined by p o l l e n a n a l y s i s . M.Sc. Thesis. Acadia Univ., W o l f v i l l e , N.S. (unpublished). Hale, M. E. J r . and W.' L. Culberson. 1970. A fourth c h e c k l i s t of the lichens of the c o n t i n e n t a l United States and Canada. B r y o l o g i s t 73: 499-543. H a l l i d a y , W. E. D. 1937. A f o r e s t c l a s s i f i c a t i o n of Canada. For. Serv. B u l l . 89. Hare, F. K. 1950. Climate and zonal d i v i s i o n s of the b o r e a l f o r e s t formations i n eastern Canada. Geogr. Rev. 40: 615-635.  147  1954.  The boreal conifer zone.  Geogr. Stud. 1:  4-18.  Hickox, C. F. J r . 1962. A late pleistocene ice cap centered on Nova Scotia. Geol. Soc. Amer. B u l l . 73: 505-510. Hulten, E. 1964. The circumpolar plants I. vascular cryptogams, conifers, monocotyledons. Kungl. Sv. Vet. Akad. Handl. Ser. 4, Bd. 7, No. 1, 275 pp. Hustich, I. 1949. On the forest geography of the Labrador peninsula. Acta Geogr. 10 (2) Helsingfors. Hutchinson, A. M. 1918. Limiting factors i n relation to specific ranges of tolerance of forest trees. Bot. Gaz. 66: 465-493. Jackson, M. L. 498 pp.  1958.  Soil chemical analysis.  Prentis-Hall Inc.  Killam, I. C. 1951. Paleoecological studies of postglacial forest succession in Cape Breton I. B.Sc. (honours) Thesis. Acadia Univ., Wolfville, N.S. (unpublished). La Roi, G. H. 1967. Ecological studies i n the boreal spruce-fir forest of the North American taiga. I. analysis of the vascular f l o r a . Ecol. Monog. 37: 229-253. Linteau, A. 1955. Forest s i t e c l a s s i f i c a t i o n of the northeastern coniferous section boreal forest region, Quebec. For. Br. Canada. B u l l . 118 85 pp. Loucks, 0. L. 1962. A forest c l a s s i f i c a t i o n for the Maritime Provinces. Proc. N.S. Inst, of Sci. 25: 85-167. Lutz, H. J. and R. F. Chandler, J r . 1946. and Sons, N.Y. 514 pp.  Forest s o i l s .  John Wiley  McDonald, A. C. 1958. A study of the transition zone in northern Cape Breton Island. B.Sc. (honours) Thesis. Acadia Univ., Wolfville, N.S. (unpublished). Macoun, J. 1899. Report on natural history. Canada. 1898. pp. 194A-200A.  Summ. Rep. Geol. Surv.  I:  Neale, E. W. 1963. Geological map of Pleasant Bay, N.S. Canada. Map 1119A.  Geol. Surv.  Nichols, G. E. 1918. The vegetation of northern Cape Breton Island, N.S. Trans. Conn. Acad. Arts & Science. 22: 249-467. . 1935. The Hemlock-White Pine-Northern Hardwood region of eastern North America. Ecology 16: 403-422.  148 Oosting, H. J . and W. D. B i l l i n g s . 1951. A comparison of s p r u c e - f i r f o r e s t s i n the northern and southern Appalachian system. Ecology 32: 84-105. , and J . F. Reed. 1944. E c o l o g i c a l comparison of pulpwood f o r e s t s i n northwestern Maine. Amer. M i d i . Nat. 31: 182-210. Place, I . C. M. 1952. The influence of bracken fern on establishment of spruce and f i r seedlings. Canada Dept. Resources and Development S i l v . L e a f l . No. 70. . 1955. The influence of,seed-bed conditions on the regeneration of spruce and f i r . Canada Dept. Northern A f f a i r s and Nat. Res. For. B u l l . 117. 87 pp. Reeks, W. A. 1953. Spruce budworm surveys i n the Maritime Provinces i n 1953. Canada Dept. Agr. S c i . Serv. For. B i o l . Div. Bi-Monthly Progr. Rep. V o l . 9 No. 6: 1. Roland, A. E. and E. C. Smith. 1969. The f l o r a of Nova S c o t i a . Scotia Museum, H a l i f a x , N.S. 746 pp.  Nova  Rowe, J . S. 1959. Forest regions of Canada. Canada Dept. Northern A f f a i r s and Nat. Res. For. Br. B u l l . 123. 71 pp. . 1972. Forest regions of Canada. Canada Dept. Canadian For. Serv. Publ. 1300. 171 pp.  Environment  Schuster, R. M. 1953. Boreal hepaticae. A manual of the l i v e r w o r t s of Minnesota and adjacent regions. Amer. M i d i . Nat. 49: 257-684. S t e e l , R. G. D. and J . H. T o r r i e . 1960. P r i n c i p l e s and procedures of s t a t i s t i c s . McGraw-Hill Book Co. Inc. Toronto. 481 pp. Thornthwaite, C. W. 1948. An approach toward a r a t i o n a l of climate. Geogr. Rev. 38: 55-94.  classification  Vincent, A. B. 1965. Black Spruce. A review of i t s s i l v i c s , ecology, and s i l v i c u l t u r e . Canada Dept. For. Publ. No. 1100. Wilde, S. A. 1946. Forest s o i l s and forest growth. Botanica, Waltham, Mass. 241 pp.  Chronica  /,  Wilton, W. C. 1964. The f o r e s t s of Labrador. For. Res. Br. No. 1066. 72 pp. Zon, R.  Canada Dept. Forestry  1914. Balsam f i r . B u l l . U.S. For. Serv. 55 1  68 pp.  149  XI  APPENDICES  l,  APPENDIX I VEGETATION TABLES  Table 1.  Association for the Upland F i r Association (Abies balsamea - Dryopteris splnulosa - Hylocomium umbratum)  2  1  Number of P l o t s Plot No.  3  5  4  1  3  4  8  upper slope  ridge top  ridge base  lower slope  6  10  8  7 18  17  19  9  10  11  12  •13  14  15  16  17  18  19  20  22  23  25  26  27  28  ! 29  30  31  32  34  35  2 Plot s i z e (m ) Landform  upper slope  ridge top  ridge bsse  lower slope  ridge base  upper slope  upper slope  upper slope  upper slope  lower i. lower slope Blope  upper slope  lower slope  lower slope  upper slope  lower slope  Relief  Slope  S  N  E  S  SW  u  W  N  NW  W  SE  NW  S  3°  0  0  3°  2°  0  0  2°  .0  2°  2°  4°  3°  4°  2°  2°  3°  2°  2°  1°  Average Coverage  62  40  25  40  47  40  49  40  43  65  40  45  33  30  25  45  28  25  60  40  41.1  40  40  45  40  15  28  25  25  30  28  40  45  52  30  40  40  34.4'  2  1  0  1  2  2  2.5  3  2  1  0.5  7.2  E  Exposure Gradient  neutral neutral  neutral neutral  neutral  S  i  Total Layer Coverage (Z) A^ layer layer  2  40  40  B^ layer  1  48 3  0  0  0  2  15  2  0  0  1  1  3  i  Bj layer  5  12  25  8  10  20  12  18  5  7  2  2  2  2  5  2  C layer  90  90  95  95  90  95  90  90  65  85  58  45  92  83  85  75  93  63  88  53  81.2  Dh layer  25  60  90  80  50  70  30  55  60  65  75  90  30  70  50  75  20  35  40  40  55.5  Ddv layer  15  15  15  20  15  15  18  10  12  15  10  15  6  10  15  5  5  5  5  10  11.8  73  65  85  85  84  85  83  68  81  83  92  81  90  86  93  92  93  87  87  89  84.1  0  0  0  2  2  1  1  0  2  2  '2  0  0  2  0  1  1  0  1  0  0  0  0  0  0  1  0  0  0  0  0  0  0  15  15  15  15  30  18  15  8  16  8  12  8  5  13  12  10  ;  Ground Surface Coverage (X) Humus ~~  Mineral S o i l  2  Exposed Rock  0  0  15  35  25  Decayed Wood  0  0  0  7  0.2 0.8 14.8 Constancy (»  F l o r i s t i c Composition and Species Coverage (X)  Average _ Coverage (X)  layer Abies balsamea  40.0  40.0  62.5  40.0  25.0  40.0  -  -  -  -  40.0  40.0  40.0  40.0  40.0  -  -  -  15.0  Picea glauca  40.0  -  7.5  40.0  40.0  -  2.5  40.0  40.0  15.0  15.0  -  -  15.0  2.5  7.5  62.5  40.0  62.5  ~  —  —  25.0  25.0  25.0  25.0  40.0  25.0  40.0 0.5  0.5  7.5  40.8  100  25.0  62.5  40.0  —  —  —  —  40.0  25.0  40.0  40.0  100  25.0  30  4.3  Aj layer Abies balsamea  2.0  Betula papyrifera  -  7.5  0.5  2.5  1.0  2.5  B^ layer Abies balsamea  _  2.5'  7.5  7.5  &2 layer Abies balsamea  2.0  Betula papyrifera Amelanchier bartramiMa  2.0  Sorbus decora  1.0 0.5  Picea glauca C Layer Dryopteris splnulosa  40.0 7.5  Comus canadenals  15.0  totalis montana  7.5  Abies balsamea Coptls t r i f o l l a  2.0  C l l n t o n i a borealis  2.5  T r l e n t a l l s borealis  7.5 2.5  Malanthemum canadense Dryopteris  2.0  Phegopteris  7.5 7.5  7.5 ' 15.0 7.5  2.0 2.0  2.5  15.0 7.5  2.5  2.0  1.0  40.0 15.0 15.0 7.5  15.0 15.0 15.0 25.0  40.0 40.0 15.0 7.5  25.0  25.0 15.0  25.0 25.0  25.0 15.0  25.0  25.0 40.0 25.0 15.0  —  Moneses u n i f l o r a Acer spicatum  —  Picea glauca  1.0  Dryopteris noveboracensis  2.0  V i o l a pallens  1.0  Carex trisperma  -  Gaultheria h i s p i d u l a  1.0  0.5  Rubus ldaeus  1.0  0.5  1.0 1.0  2.0  - --  25.0  7.5  2.5  7.5  7.5  -  0.5  1.0  Monotropa u n i f l o r a  2.5  100  5.1  2.5  100  4.3  2.0  7.5  2.5  2.0  2.5  2.5  2.5  2.5  2.5  7.5  7.5  2.5  2.5  2.5  100  3.8  15.0  2.5  2.5  -  2.5  15.0  2.0  2.5  2.5  2.5  2.5  2.5  2.0  1.0  1.0  95  4.4  2.5  2.5  15.0  2.5  2.0  2.5  2.5  7.5  2.5  2.5  2.5  2.5  95  4.2  2.5  2.5  2.0 2.5  2.0  2.0  1.0  1.0  2.5  2.0  2.0  —  0.5  1.0  95  2.0  2.5  2.0  2.0  2.0  2.0  1.0  2.0  2.5  --  2.0  2.0  1.0  2.0  95  1.9  7.5  2.5  2.5  2.5  2.5  7.5  2.5  7.5  2.5  7.5  2.5  2.5  2.5  90  5.3  2.5  2.0  2.0  2.0  1.0  2.5  2.5  2.5  2.5  2.0  —  1.0  90  2.1  2.5  2.5  7.5  2.5  2.5  15.0  15.0  15.0  15.0  2.5  7.5  2.5  2.5 7.5 2.0  2.0 15.0 2.5 2.0  7.5  2.0  1.0  2.0  1.0  - _ -  25.0  -  2.5 2.5  15.0  2.0  1.0  1.0  2.0  1.0  2.0  2.0  2.0  2.0  2.5  2.0  2.0  3.5  2.0  2.5  7.5  2.5  1.0  -  -  1 1  2.5 2.0 2.0  7.5 7.5 2.0  2.0 1.0  --  -  1.0  2.0  2.5  2.5  —  —  1.0  7.5  2.0  1.0  2.5  1.0  -  2.0  —  0.5  0.5  canadensis  Lycopodium clavatum  2.5  1.0  2.5  2.0  2.0  2.0  —  Luzula acuminata aquillnum  —  Monotropa Hypopythya Eh layer  7.5  Hylocmlum umbratum  —  —  40.0  25.0  25.0  Pleurozium schreberi  7.5  25.0  Dicranum majus  2.0  -  1.0  Sphagnum capillaceum Rhytldladelphus loreus  2.0  1.0 "2.0  25.0 2.0  25.0  25.0  25.0  2.0  40.0  25.0  2.0  1.0  2.6  2.0  2.5  2.0  2.5  2.0  -  2.5  -  2.5  2.0  __  — —  1.0  1.0  2.0  P t i l i u m crista-castrensls  -  2.0  Polytrichum commune  2.0.  2.5  Dicranum montanum  2.0  —  Cladonla spp.  1.0  —  A l e c t o r l a amerlcana  2.0  -  2.0  2.0  1.0  2.0  2.0  2.0  —  2.0  2.0  —  — ~ 2.6~'  25.0 2.0  1.0  —  —  80  1.6  ! 2 '°  2.0  2.5  1.0  1.0  2.0  70  2.1  1.0  —  —  1.0  1.0  65  7.1  2.5  2.5  3.3  2.0  -  65  2.0  -  2.0 2.0  50  1.7  2.0  - _— -i r  -  2.0  50  —  45  1.6  —  —  —  1.0  —  1.0  2.0  —  1.0  —  45  1.4  —  —  0.5  1.0  —  —  —  —  —  —  45  1.2  0.5  1.0  1.0  1.0  2.5  1.0  40  1.3  —  —  —  -  2.5  0.5  —  0.5  40  1.2 1.9  —  —  —  —  —  —  —  —  -  1.0  —  2.0  35  1.0  0.5  —  1.0  2.0  —  —  —  —  —  20  1.1  0.5  —  —  —  —  1.0  —  —  —  —  20  0.9  —  —  —  —  —  —  2.1  —  —  —  10  1.2  1.0  —  —  —  —  —  —  —  —  —  10  1.0  —  —  —  —  —  —  1.0  1.0  ~  —  10  1.0  —  —  —  0.5  10  0.8  10  0.8  2.5  1.0  2.0  1.0  7.5  40.0  2.0  2.0  —  1.0  7.5  2.6  1.0  —  25.0  2.5  85  0.5  25.0  7.5  1.0  1.0  62.5  2.0  2.0  1.0  25.0  7.5  —  1.0  —  40.0  7.5  2.5  1.0  —  40.0  2.0  4.7  1.0  1.0  15.0  7.5  85  —  15.0  7.5  2.5  —  15.0  7.5  2.5  2.0  15.0 2^5  9.2  2.5  2.0  1.0  40.0  85  15.0  —  —  —  7.5  7.5  —  1.0  1.0  L i s t e r a cordata  7.5  2.5  1.0  0.5  Lycopodium lucldulum  15.0  7.5  1.2  1.0  1.0  Rubus pubescens  2.0  15.0  —  2.0  1.0  2.5  7.5  1.0  1.0 2.0  2.0  2.5  7.5  2.5  —  1  7.5  2 5  1  _25.n 2.0  2.0  1.0  2.0  2.0  2.5  2.0  1.0  2.0  !  7.5  Bazzania  -  trilobata  Hypnum pallescens  2.0  2.0  Brachythecium curturn  2.0  2.0  Dicranum fuscescens  2.0  Plaglothecium laetum Tetraphia geniculata  -  2.0  -  2.0 2.0  2.0  -  2.0  -  1.0  90  1.8  -  2.0  1.0  80  1.8  0  2.0  2.0  2.0  •2.5  2.0  75  2.1  —  —  —  —  —  15  2.0  i 1  2  2.0  1.0  2.0  1.0  1.0  1.0  95  1.3  2.0  1.0  2.0  1.0  1.0  85  1.8  1.0  1.0  2.0  2.0  —  2.0  2.0  1.0  2.0  —  2.0  2.0  2.0  2.0  2.0  —  2.0  2.5  2.5  2.0  2.0  2.0  ~  -  1.0  —  2.0  1  2.0  2.0  2.0  2.0  2.0  2.0  2 5  2.0  o-  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  2.0  A l e c t o r l a orchrolouca  2.0  2.0  2.0  2.0  2.0  -  2.0  1 0  2.0  —  —  2.0  2.0  2.0  2.0  -  2.0  Ptilidiura c i l i a r e  —  2.0  -  —  —  —  Hypnum imponena  —  —  -  2.0  -  2.0 2.0  —  -  _  -  -  2.0  -  2.0  -  80  2.4  "  75  2.0  2.0  75  1.9  70  2.1  - - -  2.0  - - - - - - 2.0  1.0  —  1.0  1.0  —  —  2.0  70  2.0  55  1.9  50  1.9  45  1.9  15  1.3  Sporadic species (occurrence limited to 1 plot) B^ Amelanchier bartramiana  (0.5%)  Epicjaea repens (0.5%)  &2 Acer spicatum (0.5%)  Habenarla obtusata (1.0Z)  C Layer  Llnnaea borealis (2.5%)  Acer rub rum  Pyrola e l l i p t l c a  (I.OX)  Dh P e l t i g e r a apthosa (0.5Z)  Viburnum cassinoides'(1.1%)  Pogonatum alplnum (1.0Z)  Viburnum edule (0.5Z)  Sphagnum  mage H a n i cum  Sphagnum  palustre (1.0Z)  (2.0Z)  Coverage values represent midpoints of the Domin-Krajlna scale of cover-abundance (Becking, 1957) (Table 6 ) kAverage coverages were computed using only plots In which species occurred.  (1.0Z)  12.1  1.0  2.5  2.0  5.0  2.0  2 0'  2.0  -  90  2.0  2.0  2.0  95  7.5  1.4  2.0  2.0  2.5  2.5  2.0  2.0  2.0  7.5  2.0  2.0  1.0  -  2.5  1 0  2.0  2.0  11.9  2.5  2 0  2.0  29.0  100  7.5  2 0  2.0  2.0  2.0  100  7.5  15.0  2.0  2.0  2.0  2.0  1 0  Ddv layer  2.0  25.0  15.0  2.0  1.0  25.0  40.0 15.0  —  1.0  25.0  40 0  7.5 , 7 5  2.0  2 0  -  25.0  —  1.0  —  -  2.0  1.0  —  -  —  1.0  .  1.0  —  1.0  2.0  2.0  1.0  8.0  15.0  7.5  2.0  2.0  2.5  100  2.5  1.0  1.0  12.5  2.5  2.5  2.5 •  2.0  100  2.5  - -  2.5  15.0  2.5  2.5  -  15.0  2.5  15.0  2.0  2.5  17.8  25.0  7.5  1.0  2.5  25.0  100  2.5  —  Osmunda cinnamomea  Pcerldlum  2.5  15.0  7.5  25.0  7.5  - -- -- - •- -- -- -- - -' --- - - .- - -- - -- - - -- - - - -  Ribes glandulosum  Calamagrostis  —  7.5  15.0  2.5  2.0  2.5  7.5  19.8  25.0  2.5  2.5  Osmunda Claytoniana  7.5  7.5  26.5  100  2.5  15.0'  2.5  15.0  15.0  100  15.0  7.5  2.5  —  15.0  15.0  15.0  7.5  15.0  2.5  2.0  15.0  15.0  15.0  25.0  2.5  2.5  2.5  25.0  25.0  7.5  7.5  7.5  40.0  40.0  2.5  2.5  A r a l l a nudicaulis  25.0  25.0  2.5  7.5  2.5  40.0  ,5  2.0  7.5  —  25.0  2.5  7.5  2.5  2.5  7.5  15.0  40.0  7.5  1.0  —  15.0  25.0  1.5  !  2.5  7.5  2.0  7.5  1.3  15  2.5  2.5  2.5  7.5  15.0  40  2.0  2.5  7.5  2.0  2.0  25.0  3.9  5.8  15.0  15.0  25.0  60  100  2.5  2.0  15.0  ~  70  1.0  2.5  2.5  15.0  —  2.0  2.0  7.5  2.0  Sorbus decora  —  1  0.5  2.5  2.5  2.0  Aster acumlnatus  —  15.0  1  —  1.0  j  2.5  —  3.4 4.0  7.5  7.5  2.0  —  95  7.5  2.5  15.0  — —  2.0  2.5  7.5  2.5  2.0 0.52.5  7.5  2.5  —  2.5  7.5  2.5  2.5  2.5  2.5  7.5  1.0  2.5  7.5  7.5  2.0  70  2.5  7.5  2.0  2.5  2.5  7.5  7.5  2.5  2.5  15.0  2.5  0.5  2.5  2.5  1.0 *  7.5  -  i  7.5  2.5  7.5  15.0  0.5  0.5  2.5  15.0  2.5  15.0  15.0  2.5  2.5  6.1  2.5  15.0  2.0  —  15.0  15.0  70  2.5  7.5  —  macrophylla  25.0  2.5  Amelanchier  Solldago  25.0  2.5  Athyrium F i l i x - f e m i n a  2.5  15.0  25.0  7.5  2.0  roseus -  2.0  2.5  0.5  2.5  2.0  2.5  0.5  2.0  1.0  7.5  —  2.5  2.0  15.0  7.5  2.5  - - - - - - - 2.0  7.5  2.5  2.0  32.3  0.5  0.5  7.5  40.0  40.0  0.5  2.5  7.5  Streptopus  2.5  . 25.0  2.0  2.5  Betula papyrifera  bartramiana  7.5  7.5  25.0  Total number of apeciee including sporadics: Total number of species with Constancy 70Z or more: 34  ,'V.jitWo  Table I I . ,  •o  i.. ( j i  'mi L i,:  A s s o c i a t i o n Table f o r the Black Spruce A s s o c i a t i o n (Picea mariana-Pleurozium s h e r b e r i )  1 5  2 6  low area  lower s l o p e '.  Number of P l o t s P l o t No. Plot size  3  4  7  11  low area  upper slope  5 15  6 24  7 33  (m ) 2  Landform  r  Relief  ..flat...  Average Coverage (%)  T o t a l Layer Coverage (%)  0  0  %2 l a y e r  62.5 85  87 90  C layer  55  Dh  85  45 95  A2 l a y e r B^  layer  layer  5  Ddw l a y e r  0 42  0  0  40  22.5  48  42  43  62  55.2  70  60  75  43  20  50  68  38 65  20  63.3 48.4  5  5  76.8 "4.6  98  95.1  80  63 .70  5  8  2  98  98  65 8  0.5  78  Ground Coverage (%)  95  Humus  95  87  95  0...  Exposed M i n e r a l S o i l Exposed Rock  Floristic  2  5  Decayed Wood  2  5  13  5  2  Composition and Species  Coverage ( % )  4.8 Constancy  (%)  a  Average Coverage (%)  A2 l a y e r  0.5  P i c e a mariana B  1  40.0  29  22.5  62.5  100  52.8  layer  62.5  P i c e a mariana Abies balsamea  85.0 2.5  40.0 2.5  40.0 7.5  40.0 2.5  40.0  40.0 2.5  40.0  40.0  15.0  25.0  25.0  2.5  15.0  2.0  15.0  2.5  3.5  71  B, l a y e r  62.5  Nemopanthus mucronata  15.0  65.0 15.0  Rhododendron  15.0  15.0  P i c e a mariana  Viburnum  canadense  7.5  cassinoides  Amelanchier bartramiana  15.0  2.0 7.5  7.5  2.5  Kalmia a n g u s t i f o l i a  2.5  Viburnum edule  1.0  7.5 1.0  Abies balsamea  7.5 15.0 2.5  —  2.0  2.0 2.5  — —  7.5 15.0 2.5 2.5 7.5  —  7.5  41.4  7.5  100 100  2.0  2.5  100  8.5  2.5  2.5  100  6.6  2.0 1.0  2.5  100  5.6  0.5  100  4.5  86  13.1  —  29  4.0 1.0  1.0  1.0  100  9.1  1.0 2.5  2.0 2.5  100  8.3  100  6.4  7.5 2.5  2.5 2.0  100  6.4  100  4.5  2.0 ' i—  2.0  C layer  2.0  P i c e a mariana  15.0  15.0  15.0  15.0  15.0 7.5  15.0 2.5  2.5 7.5  15.0 7.5  Clintonia borealis  2.5 7.5  7.5 2.0  7.5 2.5  15.0 7.5  15.0 2.5 7.5  Coptis  2.5  2.5  7.5  2.5  2.5  7.5  2.5  100  3.9  Gaultheria hispidula  2.5  2.5  7.5  2.5  2.0  2.5  2.0  100  3.1  Nemopanthus mucronata  2.0 2.5  2.5  2.0  7.5  2.5  2.0  100  3.0  Amelanchier bartramiana  2.0 2.5  7.5  1.0  2.0  100  2.6  2.5  •1.0  2.0  2.0 7.5  1.0  Viburnum  2.5  1.0  100  2.6  7.5 2.0  7.5  7.5 1.0  7.9  2.0  — 7.5  15.0 2.5  86  Epigaea repens  7.5 2.5  2.0 2.5  2.7  2.0  2.0  2.5  '2.5  2.5  86  2.0  Taxus canadensis  7.5 7.5  — — — — 2.0  2.0  — — — — 2.0  7.5. 2.0  — 2.5  — 1.0  86  Abies balsamea  Rhododendron  canadense  Cornus canadensis Vaccinium a n g u s t i f o l i u m  trifolia  cassinoides  Kalmia a n g u s t i f o l i a  Carex trisperma  2.5 2.5  Ledum groenlandicum Rubus  Chamaemorus  2.0 2.0 2.0  Osmunda cinnamomea  — 1.0  Sorbus decora  2.0  1.0  Linnaea b o r e a l i s  2.5  2.0  Trientalis borealis  2.0  2.0  S o l i d a g o macrophylla  2.0  2.0  Maianthemum  canadense  2.5  7.5  1.0  71  4.1  1.0  2.0  71  2.9  2.0 2.0  7.5 2.5  1.0 2.0  71  2.0  2.0  — 2.0  71  3.0 2.2 2.1 1.8 1.3 2.2 1.7 2.0 1.0  2.0  2.0 0.5  57 57  2.0  43  2.0 1.0  43 29  1.0  Aralia nudicaulis  71  29  1.0  Dh l a y e r Pleurozium s c h r e b e r i  15.0  40.0  25.0  Sphagnum c a p i l l a c e u m  40.0 15.0  40.0  40.0  Bazzania t r i l o b a t a  15.0  7.5  40.0 2.5 2.5  25.0  25.0  100  27.8  7.5 15.0  7.5 15.0  40.0 2.5  100 100  25.3  2.5  7.5  7.5  100  3.9  2.5  100  5.9  2.5  2.5  100  1.7  — 7.5  2.5  86  4.1  — 2.5  43 43  3.5 2.5  2.5  100  2.1  2.0  100  2.0  2.5  2.5  2.5  2.5  2.5  2.0  Cladonia spp.  2.0 7.5  1.0  1.0 2.5  1.0 7.5  2.0 2.5  2.0 2.5  1.0  — 2.5  — —  — —  2.0  2.0  2.0  2.0  2.5  2.0  2.0  2.0  2.0  crista-castrettsis  Sphagnum subsecundum Spgagnum magellanicum Ddw l a y e r Ptilidium  2.0  ciliare  Dicranum fuscescens  2.0  Hypnum p a l l e s c e n s  2.0  2.0  —  Brachythecium curtum  Sporadic Species (occurrence l i m i t e d t o 1 p l o t )  Ledum groenlandicum (2.OX)  15.0  15.0  2.0  2.0  2.0  2.0  10.3  2.5  Dicranum majus Hylocomium splendens  Ptilium  2.5  25.0  —  2.5  57  2.1  29  2.0  T o t a l number of..species' i n c l u d i n g s p o r a d i c s :  43  T o t a l number o f species w i t h constancy 70% or more:  27  Sorbus decora (1.0%) C layer  Cinna l a t i f o l i a (0.5%) Drosera r o t u n d i f o l i a (1.0%)  P i c e a glauca (2.5%) Streptopus roseus  (o'.5%)  Ddw l a y e r  , - A l e c t o r i a orchroleuca (2.0%) Plagiothecium laetum (2.0%) Ol rO  Species coverage values represent midpoints o f the Domin-Krajina s c a l e o i Cover-Abundance  (Becking, 1957) (Table 6 ).  ''Average coverages were computed using only p l o t s where species occurred.  Table I I I .  A s s o c i a t i o n Table f o r the Swamp F i r A s s o c i a t i o n (Abies balsamea - Osmunda clnnamonea. - Sphagnum capillaceum)  Number of P l o t s  1  2  3  4  5  6  7  P l o t . No.  2  9  16  20  21  36  37  Plot  s i z e (m ) 2  Land form  r i d g e base  lake shore  r i d g e base  depression  Relief  Average Coverage (%)  t o t a l Layer Coverage (%) A^ l a y e r  25  40  5  0  10  17  25  Aj layer  50  40  55  42  45  15  25  38.9  B^ l a y e r  15  15  15  20  15  2  15  13.8  layer  50  55  45  50  58  10  15  40.4  layer  95  90  90  95  90  96  88  92.0  Dh l a y e r  35  50  60  65  35  20  40  43.6  Ddw l a y e r  10  15  15  10  15  15  15  13.6  90  90  92  95  84  90  90  90.6  0  0  0  0  1  2  0  0.4  10  10  15  C  -  17.4  Ground Coverage (%) Humus Mineral S o i l  0.0  Exposed Rock Decayed Wood  10  15  8  10  11.1 Constancy  (Z)  Average Coverage (Z)  F l o r i s t i c Composition and S p e c i e s Coverage (Z) A. l a y e r Abies balsamea  25.0  40.0  P i c e a glauca  2.5  7.5  15  2.5  7.5  2.5 15.0  25  86  19.2  0.5  57  3.3  25.0  100  34.2  71  8.5  100  13.2  43  2.5  43  2.3  Aj layer Abies balsamea  40.0  40.0  40.0  40.0  40.0  P i c e a glauca  15.0  2.5  15.0  2.5  7.5  15.0  15.0  15.0  15.0  15.0  2.5  2.5  layer Abies balsamea  2.5  P i c e a mariana  2.5  Alnus rugosa  2.0  2.5  2.5  15.0  layer  15.0  40.0  25.0  25.0  15.0  2.5  15.0  100  19.6  Amelanchier bartramiana  7.5  2.5  7.5  15.0  15.0  2.0  2.0  100  7.4  Sorbus  decora  7.5  2.5  2.5  7.5  2.5  2.0  0.5  100  3.6  Nemopanthus mucronata  1.0  7.5  1.0  2.5  2.5  86  2.8  Picea glauca  -  -  2.0  2.0  2.5  2.0  0.5  71  2.9  7.5  15.0  -  7.5  -  -  71  14.0  2.5  71  2.0  -  Abies balsamea  Alnus rugosa Betula papyrifera Picea  mariana  Viburnum c a s s i n o i d e s  15.0 2.0 15.0 0.5  C layer  7.5  25.0  -  -  2.0  1.0  2.5  2.5  -  2.5  -  -  -  7.5  2.0  2.0  57  6.9  1.0  57  1.5  Osmunda cinnamomea  85.0  40.0  40.0  40.0  15.0  62.5  15.0  100  42.5  Cornus canadensis  15.-0  15.0  25.0  15.0  15.0  2.5  15.0  100  14.6  7.5  15.0  25.0  15.0  15.0  2.5  7.5  100  12.5  7.5  15.0  25.0  15.0  15.0  2.5  2.5  100  11.8  Coptis  trifolia  Abies balsamea Dryopteris spinulosa  40.0  15.0  7.5  2.0  7.5  7.5  1.0  100  11.5  Solidago macrophylla  2.0  25.0  2.5  7.5  15.0  1.0  2.0  100  7.9  Aralia nudicaulis  7.5  2.5  7.5  2.5  7.5  2.5  7.5  100  5.4  Linnaea b o r e a l i s  2.5  2.0  2.5  2.5  2.5  15.0  7.5  100  4.9  Sorbus  2.0  2.5  15.0  7.5  2.5  2.0  2.0  100  4.8  2.5  7.5  7.5  7.5  7.5  2.0  2.5  100  4.6  7.5'  100  3.9  decora  O x a l i s montana Clintonia borealis  2.5  2.5  7.5  2.5  2.5  2.0  Maianthemum canadense  1.0  2.5  7.5  2.5  2.0  2.0  7.5  100  3.6  Trientalis borealis  2.5  2.5  2.5  2.5  2.5  2.0  2.5  100  2.4  Gaultheria hispidula  2.0  2.5  2.5  2.5  2.0  2.5  2.0  100  2.3  P i c e a glauca  2.5  2.5  2.5  2.5  2.5  1.0  1.0  100  2.1  2.0  2.5  2.5  2.5  2.5  1.0  1.0  100  2.0  7.5  -  7.5  2.5  25.0  7.5  2.5  86  2.5  2.5  2.5  2.0  2.5  86  4.5  Vaccinium a n g u s t i f o l i u m  1.0  2.0  2.0  2.0  -  -  8.7  15.0  2.0  2.0  86  1.8  Nemopanthus mucronata  -  15.0  2.5  1.0  2.0  2.0  71  4.5  Viburnum c a s s i n o i d e s  -  2.0  7.5  2.0  -  1.0  2.0  71  2.9  Streptopus roseus  1.0  2.0  2.0  2.0  2.5  71  Taxus canadensis  2.0  0.5  -  1.9  1.0  1.0  1.1  Alnus rugosa  -  2.5  1.0  2.5  1.0  1.0  2.5  2.0  1.0  -  2.0  Amelanchier Aster  bartramiana  acuminatus  Carex t r i s p e r m a  Calamagrostis canadensis  -  2.0  2.5  Epiqaea repens  1.0  2.0  -  Pyrolla e l l i p t i c a  -  -  D r y o p t e r i s novaboracensis  Habenaria obtusata  2.0  2.0 2.0  2.0  Rubus idaeus  -  -  Iris  -  -  Betula papyrifera  1.0  1.0  -  Rubus Chamaemorus  Picea  mariana  versicolor  2.5  -  2.0  -  -  2.5  -  1.0  71  -  57  1.7  57  1.6  -  43  2.2  -  -  43  1.7  15.0  15.0  29  15.0  -  -  -  29  2.5  2.0  2.5  29  2.3  -  29  2.0  -  29  2.0  2.0  0.5  29  1.3  -  -  -  -  29  1.1  -  -  layer Sphagnum c a p i l l a c e u m  25.0  25.0  40.0  40.0  25.0  15.0  25.0  100  27.9  Pleurozium s c h r e b e r i  2.5  7.5  15.0  15.0  2.5  2.5  7.5  100  7.5  Hylocomium umbratum  2.5  7.5  2.5  15.0  7.5  1.0  2.5  100  4.9  Dicranum majus  2.0  2.5  2.5  2.5  2.5  2.0  2.5  100  2.4  Ptilium  100  1.8  2.0  2.5  2.0  2.0  '1.0  Sphagnum mage H a n i cum  2.5  2.0  2.0  2.0  2.0  Hylocomium splendens  2.0  -  2.0  P o l y t r i c h u m commune  -  -  -  Bazzanla t r i l o b t a  2.0  Ptilidium  crista-castrensls  1.0  2.0  -  -  71  2.1  2.0  2.0  57  2.0  2.0  2.0  29  2.0  2.0  2.0  29  2.0  -  -  -  2.5  2.0  2.0  1.0  2.0  2.0  100  1.9  2.0  2.0  2.0  2.0  1.0  2.0  2.0  100  1.9  Dicranum fuseescens  2.0  2.0  1.0  2.0  2.0  2.0  1.0  100  1.7  Alectoria  1.0  2.0  2.0  1.0  2.0  1.0  1.0  100  1.4  Sphagnum p a l u s t r e  -  layer  ciliare  americana  Cladonia spp.  2.0  1.0  1.0  1.0  2.0  1.0  2.0  100  1.4  Rhytidiadelphus loreus  2.0  2.0  2.0  2.0  2.0  2.0  86  2.0  Plagiothecium laetum  2.0  2.0  2.0  2.0  2.0  1.0  86  1.7  2.0  2.0  -  2.0  1.0  1.0  71  1.6  Tetraphis geniculate  -  2.0  2.0  1.0  2.0  1.0  71  1.6  A l e c t o r i a orchroleuca  2.0  2.0  -  1.0  57  1.5  Hypnum imponens  -  1.0  -  -  1.0  1.0  -  -  Hypnum p a l l e s c e n s  -  r a d i c Species (occurrence l i m i t e d t o 1 p l o t ) «2 l a y e r B e t u l a p a p y r i f e r a (0.5Z) layer Acer spicatum (1.0Z) P i c e a glauca (2.0Z) Bj layer Acer rubrum (0.5%)  -  T o t a l number o f Species i n c l u d i n g S p o r a d i c s : T o t a l number o f s p e c i e s o f Constancy C layer  Prenanthes  70Z o r more:  68 40  t r i f o l i o l a t a (0.5Z)  P t e r i d i u m aquilinum (1%) Viburnum edule (1Z) V i o l a p a l l e n s (2Z) Dh Dicranum montanum (1Z) Sphagnum squarrosum  (1.0Z)  Kalmia a n g u s t i f o l i a (2.0Z) C layer Acer rubrum (2.0%) A s t e r r a d u l a (2.0%) D r y o p t e r i s Phegopteris (1.0Z) Equisetum s y l v a t i c u m (3.0Z) Kalmia a n g u s t i f o l i a (2.0%) Lycopodium clavatum (0.5%) M i t c h e l l a repens (7.5%) Monotropa u n i f l o r u s (1%) Osmunda C l a y t o n i a n a (25%)  a  S p e c i e s Coverage values represent midpoints o f t h e Domin-Krajlna S c a l e o f Cover-Abundance (Becking, 1957) (Table 6 )  'Average Coverages were computed using only p l o t s where s p e c i e s o c c u r r e d .  Table IV. i o n a l Stages of the Upland F i r Associati on. Table f o r Success  Association  1  Number of Plots  12  Plot No. Plot size  .  2  Average Coverage (%)  3 13  14  100  m  .... ridge-top  Landform  ....Hummocky  Relief Layer Coverage (%)  7.5  16.2  15  0  15.0  10  25  27  20.7  50  55  80  61.6  B2 layer C layer  85  80  70  78.3  45  10  30  28.3  Dh layer  8  10  10  7.3  83  92  80  2  3  10  5.0  15  10  10  11.7  A^ layer  25  0  A2 layer  0  layer  Ddw layer Ground Coverage (%) Humus Mineral S o i l Exposed Rock Decayed Wood  85.0  Constancy (%)  F l o r i s t i c Composition and Species Coverage ( % ) a  A^ layer Abies balsamea A  2  layer 15.0  Abies balsamea B^ layer Abies balsamea  2  16.2  33  15.0  25.0  2.5  100  12.5  —  —  —  25.0  33  25.0  Betula papyrifera  15.0  25.0  40.0  100  26.7  Abies balsamea  15.0  25.0  25.0  100  21.7  Rubus idaeus  15.0  7.5  15.0  100  12.5  1.0  15.0  66  8.0  7.5  66  4.8  66  2.5  Betula papyrifera B  10.0  66  7.5"  25.0  layer  (  Sorbus decora  —  Prunus pennsylvanica  2.0  Ribes glandulosum  2.5  2.5  —  15.0  2.5  15.0  100  10.8  15.0  2.5  15.0  100  10.8  15.0  2.0  15.0  100 .  10.7  7.5  2.5  15.0  100  8.3  15.0  7.5  2.5  100  8.3  7.5  7.5  100  7.5  2.5  7.5  7.5  100  5.8  7.5  2.0  7.5  100  5.7  2.0  1.0  7.5  100  3.5  C layer Cornus canadensis Dryopteris  spinulosa  Abies balsamea Oxalis montana Rubus  idaeus  Ribes glandulosum Aster acuminatus Carex trisperma T r i e n t a l i s borealis  • 7.5 •  Coptis t r i f o l i a  2.5  2.5  2.0  100  2.3  Maianthemum canadense  2.5  2.0  2.0  100  2.2  Monotropa u n i f l o r a  1.0  2.0  1.0  100  1.3  Calamagrostis  2.0  40.0  66  21.0  Linnaea borealis  7.5  2.5  66  5.0  A r a l i a nudicaulis  7.5  —  66  4.8  Solidago  2.0  7.5  66  4.8  66  2.0  66  2.0  66  1.8  0.5  66  1.3  canadensis  macrophylla  ,—  — — 2.0  — 2.0  Clintonia borealis  2.1  V i o l a pallens  2.0  2.0  Sorbus decora  1.0  2.5  Amelanchier  2.0  —  Hylocomium umbratum  15.0  2.5  15.0  100  10.8  Pleurozium schreberi  15.0  2.5  2.5  100  6.7  Sphagnum capillaceum  7.5  1.0  7.5  100  5.3  Polytrichum commune  2.0  2.0  2.5  100  2.2  Dicranum majus  2.0  2.0  100  2.0  Polytrichum  2.0  —  2.0 2.0  2.0  2.0  2.0  —  66 66  2.0  fuseescens  2.0  2.0  2.5  100  2.2  A l e c t o r i a americana  2.0  2.0  2.0  100  2.0  A l e c t o r i a orchroleuca  2.0  2.0  2.0  100  2.0  2.0  2.0  66  2.0  2.0  2.0  66  2.0  2.0  66  2.0  bartramiana  — —  layer  juniperinum  •Ptilium c r i s t a - c a s t r e n s i s w layer Dicranum  Plagiothecium laetum  — —  Ptilidium ciliare  2.0  Brachythecium curtum  oradic species  (occurrence  —  limited to 1 p i ot)  layer Viburnum cassinoides (2.0%]  Total number of species including sporadics:  C layer Acer rubrum (0.5%)  47  Total number of species with constancy  Athyrium F i l i x - f e m i n a (2.0%)  of 66% or more:  36  Betula papyrifera (1.0%) Dryopteris Phegopteris  (2.0%)  Gaultheria h i s p i d u l a (7.5%) Picea glauca (0.5%) Prunus pennsylvanica Pyrolla e l l i p t i c a  (0.5%)  (2.0%)  Sphagnum subsecundum (1.0%) D Layer Rhytidiadelphus  loreus (0.5%)  Ddw layer Dicranum montanum (2.0%) Tetraphis geniculata (2.0%) Coverage values represent midpoints of the Domin-Krajina scale of Cover Abundance (Becking, 1957) (Table 6 ).. Average coverages were computed using only plots i n which species  occured.  APPENDIX I I TERMINOLOGY USED I N S O I L  DESCRIPTIONS  157  Table I . Terminology Used For Root Descriptions. ( Canada Department of Agriculture, 1970 ) Abundance Classes  Number Per Unit Area of Surface  very few  less than 1  few  1 to 3  plentiful  4 to 14  abundant  more than 14 Diameter Classes very fine : 0.075 to 1 mm. fine  : 1 to 2 mm.  medium  : 2 to 5 mm.  coarse  : more than 5 mm.  158  Tablell.  Terminology Used for Rock Fragments i n Soils. ( Canada Dept. Agriculture, 1970 ) Size  Name  up to 3 inches i n  gravel  diameter. cobbles  3 to 10 inches i n diameter.  boulders  10+ inches i n diameter. Abundance Classes Class  Area Coverage (%  1  0-5  2  5-25  3  25-50  4  50-75  5  75-100  APPENDIX I I I CLIMATE DATA FOR  THE CAPE BRETON P L A T E A U  160 Table I. Maximum and Minimum Temperatures  ! Recorded on the Cape Breton Plateau  Daily 5  4  7  6  9  8  10  11  12  Temperatures  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  12  13  21  22  23  23  21  25  17  16  21  23  21  18  14  14  21  18  -1  -1  6  12  13  14  18  17  9  7  7  10  12  6  8  4  9  23  22  23  25  23  21  26  26  17  16  21  24  22  19  14  13  19  17  6  17  13 ; 13  17  16  15  11  9  7  9  11  6  8  9  6  8  June 1970 Station  Max.  01  Min.  Station  Max.  02  Min.  8.  31  20  Station  Max.  12  15  23  24  26  24  21  26  18  15  21  26  24  20  03  Min.  1  -1  4  12  13  15  17  16  11  10  6  9  11  4  8  10  3  1* .  i1 1  July 1970 Station  Max.  11  21  21  19  18, 26  24 . 26  18  11  17  19  21  20  23  26  21  23  24  18  16  24  27  29  26  28  27  26  27  01  Min.  9  9  14  13  10 .  8  15  15  17  9  6  6  11  14  17  17  11  7  14  14  9  9  10  16  18  19 • 20  11  12  Max.  11  22  22  19  20  27  25  27  18  11  18  18  22  22  23  26  22  22  23  18  16  25  27  31  26  28  28  27  27  Min. 10  9  13  13  io  15  16  16  9  6  5  10  15  16  17  16  10  14  13  10  9  10  17  17  18  19  14  14  21  21 .20  27  26  27  21  17  17  19  22  21  24  26  22  23  23  19  16  24  26  29  26  28  10  7  14  16  17  9  6  5  14  17  17  15  8  13  16  13  8  15  17  18  Station 02 Station . 03  Max.  . 13  Min.  8  August 1970 Station 01 Station 02  28  20  20  2i  23  22  23  24  20  20  18  27  27  28  28  20  14  21  18  17  17  19  18  19  16  12  11  Min. 16  16  12  7  18  17  16  9  15  13  16  14  18  18 • 19  15  5  2  11  10  9  12  12  12  11  4  4  Max. 29  17  21  21  27  24  19  18  17  26  28  29  27  21  16  20  18  17  16  18  17  18  16  Min. 15  12  10  10  14  14  16  14  16  15  18  18  18  15  12  6  14  9  9  12  12  12  9  27  21  15  19  18  16  17  19  17  18  16  12  12  12  1  15  11  2  9  14  8  12  12  11  14  10  . 9  6  21  13  14  8  17  19  13  10  8  4  ,3  11  Max.  Station  Max.  23  23  19  20  18  24  27  28  03  Min.  16  10  16  13  16  17  16  17  :  1  June 1971 Station  Max.  11  Min.  i  8  Table I  8 July  1971  Station 11  Max.  10  11  12  13  14  15  161 17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  25  21  18  18  20  19  23? 24  27  24  21  18  21  24  26  21  24  24  21  25  24  24  17  11  9  11  12  13  141 15  13  15  14  13  12  14  17  8  6  16  11  6  18  19  19  18  9  16  21  23  24  16  22  Min. 16  9  7  6  2  15  18  12  11  22  26 22  21  17  17  22  24  23  28  28  26  22  22  15  18  18  12 19  20  11  12  8  13  16  17  21  16  14  14  13  16  August 1971 Station 11  Max.  161  (Continued)  14  Table I I 1970 Precipitation Totals for the Cape Breton Plateau Precipitation (cm)  Location  Station  June 27  July 6  June 13  June 19  to June 19  to June 27  0.7  0.4  4.3  2.9  0.4  4.2  0.8  to July 6  July 13  to  to July 13 Aug 6 4.0  Aug 6  Aug 13 to  Aug 19  Aug 19  Aug 30  15.0  3.6  12.9  .8.8  3.1  13. 2  to Aug 13  to  01 Station 02  Table I I I  1971 Precipitation Totals for the Cape Breton Plateau Precipitation  Location  June 25 to July 4  Station  July 4 to July 11  July 11 to July 17  July 17 to July 24  (cm) July 24  Aug 3  Aug 8  to  to  to  Aug 3  Aug 8  Aug 17  9.1  1.0  0.2  3.0  0.5  4.1  13.3  3.0  2.3  0.2  2.0  0.8  3.0  16.7  7.4  0.8  0.2  3.3  1.5  4.6  10.9  11 Station 12 Station 13  Table IV 1970 Wind Measurements for Plateau Station 01 June 14 to  Total Wind  June 20 to  June 27 to  July 6 to  July 11 to  June 20  June 27  July 6  July 11 July 25  2469.7  1931.2  2488.1  1443.8  445.6  270.0  18.9  11.2  July 25 to  July 28 to  Aug 6 to  Aug 13 to  Aug 19 to .  July 28  Aug 6  Aug 13 Aug 19  Aug 30  4597.7  419.7  2338.5  1594.4 1632.5  3361.1  310.6  328.4  261.2  259.8  283.9  285.2  330.6  13.0  13.7  10.8  10.8  11.9  11.9  13.3  (Km)  Mean Wind  284.0 .  Km/day Km/hr  12.0  Table V  June 25 to  Total Wind  1971 Wind Measurements for Plateau Station 11  July 4 to  July 11 to  July 17 to  July 23  Aug 3  Aug 8  to  to  to  Aug 14 to  July 4  July 11 July 17  July 23  Aug 3  Aug 8  Aug 14 Aug 17  2126.2  1730.6  1375.7  1281.2  2351.7  1156.1 1528.7 998.8  233.6  249.7  233.9  214.9  210.6  228.9  9.7  10.5  9.7  9.0  8.7  9.5  (Km ) Mean Wind Km/day Km/hr  263.6 319.6 10.9  13.4  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0100007/manifest

Comment

Related Items