Translation of Rowes (1974)a vegetation classification to the vegetation types (TEMVEG) used in the Terrestrial Ecosystem Model.
This Region comprises the greater part of the forested area of Canada, forming a continuous belt from Newfoundland and the Labrador coast westward to the Rocky Mountains and northeastward to Alaska. The white and black spruces are characteristic species; other conifers are tamarack which is absent only in the far northwest, balsam fir and jack pine prominent in the eastern and central portions, and alpine fir and lodgepole pine in the extreme western and northwestern parts. Although the forests are primarily coniferous, there is a general admixture of broadleaved trees such as white birch and its varieties, trembling aspen and balsam poplar; the latter two species playing an important part in the central and south-central portions, particularly in the zone of transition to the prairie. In turn, the proportion of black spruce and tamarack rises northward, and with increasingly rigorous climatic and soil conditions the closed forest gives way to the subarctic open lichen-woodland which finally merges into tundra. In the east, a considerable intermixture of species from the Great Lakes-St. Lawrence forest such as eastern white and red pines, yellow birch, sugar maple, black ash, and eastern white cedar occurs.
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Map Symbol |
TEMVEG |
Description from Map Legends of Rowe (1974)a |
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B.la |
Laurentide - Onatchiway:
The Section comprises the Laurentide uplands and the more southern portions of the Laurentian peneplain from the Saguenay River eastward to Sept-Iles. On the north side the boundary marks a change in dominance by balsam fir to that of black spruce on upland sites (in B.1b), while to the south as well as centrally around the Lake St. John valley the Section is bounded by forests whose composition places them in the Great Lakes- St. Lawrence Forest Region. Within this and the following Section, the bulk of the pulpwood supply of the province of Quebec is found. The forests are predominantly coniferous. Balsam fir dominates on hill slopes and on other moist well-drained sites, while black spruce is prominent on thin-soiled plateaus and on poorly-drained land. White spruce is distributed throughout, though of little numerical importance. White birch is the common hardwood associate of the fir and spruce; trembling aspen and jack pine are secondary species which dominate where fires have been frequent, especially surrounding the Lake St. John lowland. Balsam poplar, eastern white cedar, eastern white pine and tamarack are locally common while several of the tolerant hardwoods -- sugar maple and yellow birch -- occur at low altitudes in the southern parts. The terrain is rolling and in part mountainous. Broadly speaking, the entire area is underlain by crystalline rocks of Precambrian age. Swift streams in sharply cut trenches mark areas of steep gradient adjacent to Lake St. John, the Saguenay and St. Lawrence rivers; farther back, on the gentler topography of the Laurentide uplands, streams radiate out in broader valleys. On the surface drift, soils of the ferro-humic and humo-ferric podzol groups are commonly developed. Shallow and deep peats characterize dwarf-shrub uplands and moss-bog lowlands, respectively. |
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B.lb |
Chibougamau - Natashquan:
Along the south-facing slopes of the Laurentian peneplain, between the productive fir-spruce forests of the preceding section and the subarctic lichen-woodland to the north, lies a productive forest belt in which black spruce is the most abundant tree. The prominence of this species both on peaty lowland sites and on well-drained upland drift and rock, plus the relative scarcity of white spruce and balsam fir, makes for a limited variety of cover types. Groves of white birch occur here and there throughout the Section, but the other boreal hardwoods -- trembling aspen and balsam poplar -- are less conspicuous except in the immediate vicinity of rivers and lake shores. Jack pine is confined to the western side of the Section. Evidences of a severe fire history are seen both in the upland heath barrens and open woodlands of the north and in the barren rock hills along the St. Lawrence River to the south. The topography varies from rugged in the east where drainage is southward in deep valleys, to gently rolling or almost level in the west where , as in the Chibougamau area, less deeply incised rivers meander over sand plains and drain westward. Climatic conditions are less favourable for forest growth than in B.1a, due to a colder climate and a shorter growing season. Humo-ferric podzol profiles are typically developed in the surface materials, particularly in association with dwarf shrubs and spruce cover. Peaty phase gleysols occupy the narrow swamps between hills, while relatively fertile ferro-humic podzols are locally developed on richer tills in association with balsam fir. |
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B.2 |
Gaspé: The Section comprises the plateau-like highlands of the Gaspé, which are a northeastward extension of the Appalachian mountain system. Here are two islands of boreal forest, the larger coinciding generally with the uplands of the peninsula (though extending down to the south shore of the Gulf of St. Lawrence), and the smaller west of the Matapedia River valley, extending from Quebec into northwestern New Brunswick. The major forest cover types are dominated by conifers, though mixed conifer-hardwood stands are not uncommon. Balsam fir, black spruce and white spruce, often in combination with white birch, form the characteristic cover types. In addition to pure stands of balsam fir and black spruce, mixed stands of fir-spruce often with eastern white cedar are common. Forest cover is continuous except on the exposed portions of the plateaus where climate-induced alpine tundra occurs, adjacent to which both fir and spruce show strong wind effects. On the lower slopes of the Section, and in the river valleys at its edges, there are local representations of species such as eastern white pine, sugar maple, and yellow birch from the adjacent Great Lakes - St. Lawrence Forest Region, as well as some red spruce from the Acadian Forest Region. Elevations on the irregular, rugged plateaus range up to an average of 3,000 feet, with Mount Jacques Cartier reaching an altitude of 4,160 feet. Numerous small streams, deeply cut into the underlying soft sedimentary rocks, radiate outward in all directions from the uplands. Thin humo-ferric podzol profiles, with rather heavy but poorly structured Bfh horizons, are common in the well-drained position, while acid peats are developed in areas of poor drainage. | |
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B.3 |
Gouin:
The Section covers a relatively flat plateau on the height of land between the James Bay and St. Lawrence watersheds in Quebec, from which streams flow to all points of the compass. To the north are many of the headwaters of the Chibougamau River and of streams flowing into Lake St. John. In the eastern part is the large chain of lakes from which the St. Maurice River flows; to the south lie parts of the Lièvre, Gatineau and Ottawa rivers, and to the west is situated the upper part of the Bell River. As on many sandy areas, jack pine is particularly conspicuous to the casual traveller because most of the roads follow the well-drained sand flats. Black spruce, the usual associate of jack pine, is abundant not only in the muskeg of water catchment areas but also on the sand plains where, like the pine, its establishment is favored by frequent fires. Both species are found in open stands with a lichen ground cover but more commonly in closed-crown types where, however, productivity is rarely high. Mixedwoods of trembling aspen, balsam poplar, white birch, white spruce and balsam fir, occupy the upland till sites and the alluvium along rivers and lakes. Such mixed stands are similar to those of Section B.1b, though somewhat less rich in shrub and herb undergrowth. The plateau is underlain by gneisses and granites of Precambrian age. Relief is low, and the streams and rivers run slowly, meandering in shallow beds over the sand plains or traversing the local bedrock or till deposits in short, rapid stretches. On the shallow tills, fluvial terraces and glacial outwash, humo-ferric podzol profiles which generally lack either an ortstein or placic horizon have been developed. Peaty soils occupy the extensive poorly-drained sites. | |
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B.4 |
Northern Clay:
Occupying the central portions of the gentle northward slopes of the Laurentian plateau in Quebec and Ontario, the forests of this Section are conditioned by widespread surface deposits of water-worked tills and lacustrine materials, and by a nearly level topography -- inheritances from glacial Lake Ojibway. It is bounded on the north by marine clays over sedimentary and igneous rocks of the Hudson Bay Lowlands Section (B.5), where the forests tend to be stunted and open-grown, and on the south by rolling glaciated uplands where the appearance of species from the Great Lakes - St. Lawrence Forest Region marks a transition zone. The impressive characteristic of the "Clay Belt" is the seemingly endless stretches of stands of black spruce which cover the gently rising uplands as well as the lowland flats, alternating in the latter position with extensive sedge fens and sphagnum-heath bogs. Tamarack is an infrequent companion of the black spruce except in young stands. Extensive areas of spruce-cedar swamp occur but eastern white cedar reaches tree size only at the swamp borders and is rather less common in the east than in the west. Improvement in drainage, due either to slight changes in relief, to shallowly buried coarse drift or to position besides rivers and lakes is reflected in fine hardwood or mixedwood stands of trembing aspen, balsam poplar, balsam fir, white spruce and black spruce. Jack pine has a dominant position on many of the drier sites such as outwash deposits, old beaches and eskers; white birch is also prominent on sandy soils. The area is underlain mainly by Precambrian volcanic and granitic rocks, with lesser sediments. During glaciation the bedrock was partly covered by drift which in turn was modified by wave action and/or the deposition of lacustrine materials. Driftless areas of bedrock were also covered by lacustrine deposits, and therefore, the topography is generally unbroken and relatively level with only occasional hills and ridges. Eskers and outwash plains which cross the "Clay Belt" from north to south are partially or entirely covered by the lacustrine deposits. The absence of surface rock, the extensive poorly-drained flats, relatively few lakes, and clay-banked, rather sluggish streams are characteristic. Gray luvisols have developed on the calcareous upland clays and modified tills, with peaty phase gleysols widespread on the flats particularly in the Quebec sector. There are large areas of shallow organic soils, mostly composed of sphagnum moss but with woody peat beneath. On the more siliceous shallow tills to the south and on sand ridges, a humo-ferric podzol profile is usual. |
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B.5 |
Hudson Bay Lowlands: An area of Palaeozoic sedimentary bedrock overlain with marine clay and beach sand deposits borders the south and west sides of James Bay and the west side of Hudson Bay north to Churchill. It extends back to an elevation of about 500 feet above sea level, and is characterized by a flat topography and poor drainage. The rivers cross this coastal plain in roughly parallel courses with a minimum of cross-drainage, their low alluvial banks providing suitable conditions for good growth of forests. Back from the rivers lie immense areas of swamp, bog and muskeg. The vegetation of the Section has in general a "subarctic" appearance because of the prominence of an open woodland of black spruce and tamarack in the muskegs and patterned fens. Frequently, too, the organic surface supports a dense cover of light-coloured lichens. However, on the riverbank levees, where conditions of better drainage obtain, forests of white spruce, balsam fir, trembling aspen, balsam poplar and white birch occur, in quality similar to those within the Northern Clay Section (B.4). The south James Bay area contains most of the exploitable timber resources, and logging activity for lumber and pulpwood is largely confined to areas in the vicinity of the major rivers. Here also are found outposts of such species as white elm, black ash and eastern white cedar. Jack pine is sparingly present. Northwestward the percentage of peatland and of lakes increases, and the prevalent forest is of stunted open-grown black spruce and tamarack. On the west side of James Bay, as on the coast of Hudson Bay in general, black spruce does not appear to be as well adapted to the sea-shore environment as white spruce, and the latter species forms the maritime treeline. The surface materials of the marine flats are calcareous clays, derived by glacial action from the underlying Palaeozoic sediments and deposited in sea waters. In the Kesagami Lake area, the deposits are shallow over igneous rock of the Precambrian Shield. Organic soils predominate, some associated with perennially frozen ground. In the well-drained position on alluvium and on ridges, weak eutric brunisol soil profiles have developed. |
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B.6 |
East James Bay: Crustal uplift on the eastern side of James Bay has resulted in terraced topography resembling a series of steps descending from east to west. The highest well-defined terraces in the glacial drift are at approximately 300 feet above present sea level, though river action has exposed stratified marine clays and sands which extend up the valleys between the rolling rock hills to elevations of more than 500 feet. As a consequence of the deep soils, conditions for forest growth are more favorable than those found over the northern parts of Quebec and Labrador to the east or than those of the poorly-drained coastal plains of James Bay and Hudson Bay to the west. The richest forests occur below the highest marine limit on the modified deposits of glacio-fluvial materials. In the sheltered valleys white and black spruce, balsam poplar, trembing aspen, white birch and balsam fir reach merchantable sizes; poor-growing black spruce, jack pine and tamarack are found on the thin tills of the intervening rock uplands. The limits of the Section to the east are indicated by a marked diminution in the abundance and quality of white spruce, balsam fir and balsam poplar, species apparently favoured by the marine influences. Back from the shore line there are limited areas of low-lying swamps, and on dry highlands the subarctic type of open lichen-woodland appears. The pre-glacial hilly topography of the Precambrian rock uplands has been partly subdued by a covering of stony till and, at lower elevations, by the terraced marine deposits which blanket the surface near the coast and fill the inland valleys. Through the latter, swift streams are presently cutting narrow channels in the stratified sands and clays. Humo-ferric podzol soil development can be expected on the upland drift, and peaty phase gleysols on the lowlands. |
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B.7 |
Missinaibi - Cabonga: Along the height of land in central Ontario and Quebec is a Section of intermediate nature. It is basically of the Boreal Forest Region in-sofar as the bulk of the species and their distribution are concerned but contains within it certain species from the Great Lakes - St. Lawrence Forest Region either as scattered individuals or as more or less isolated patches. In position it stretches from the middle St. Maurice Valley along the higher southward slopes of the Laurentians in Quebec to the south side of Lake Abitibi, from whence westward to a point just northeast of Lake Superior it occupies the height of land between Hudson Bay and the Great Lakes. Its northern boundary coincides very generally with the northernmost limits of eastern white pine, red pine, yellow birch, sugar maple and eastern hemlock. The predominant forest is mixed in character, consisting of an association of balsam fir, black spruce and white birch with scattered white spruce and trembling aspen, this appearing as a dominant type on middle slopes. In recent years birch dieback has been severe, and the balsam fir has suffered from the devastation of the spruce budworm. The results of the disease are seen in vast areas of open, snag-filled forests in which a proliferation of shrubs such as mountain maple and hazel retard regeneration of the valuable softwoods. Here and there will be found, on heavier-textured ridges and on upper north slopes in particular, groves or single trees of both sugar maple and yellow birch -- a condition most commonly encountered in the Quebec portion. On rocky shores, and also on ridges, there is some presence of eastern white and red pine, though these species were mostly removed by logging several decades ago. Sand terraces along the rivers are dominated by jack pine, which species also associates with black spruce on poor, rocky soils. The black spruce, with tamarack, covers large areas of wet organic soils, and eastern white cedar accompanies black spruce in another common lowland association. There are numerous occurrences of black ash and white elm; red spruce is scattered here and there along the southern boundary in Quebec. The topography is rolling, but with numerous flats along the rivers and lake sides. The underlying granitic, volcanic and sedimentary rocks are of Precambrian age, and from them the shallow till overburden has inherited varying degrees of fertility, from poor in the eastern portion where magnetite and other iron-bearing minerals are undesirable components, to richer in the central and western portions where rocks such as greenstone occur. In western Quebec there has been some water modification of the surface drift -- probably relating to glacial lakes Ojibway and Barlow -- and silty surface deposits are frequent. The soil profile is typically a hummo-ferric podzol, and on the poorer acid drift with heath-and-conifer cover the presence of cemented pans (ortstein) has been observed. |
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B.8 |
Central Plateau: North of the rugged and rocky Lake Superior coastal strip, a relatively level plateau-like country extends northeastward in a gentle slope to the sparsely forested coastal plain around James Bay. On its western side the Section is in contact with the Nipigon basin and the transitional forests of the upper English River; eastward it meets the "Clay Belt" and the transitional forests of the preceding Section (B.7). Extensive sand and gravel deposits, and low rocky outcrops, provide a favourable environment for the prevalent jack pine. Black spruce types are well developed, from those occupying the shallow swamps to those of maximum productivity on the better-drained level or undulating land. Mixture of the two conifers is common and white birch and trembling aspen occur within the same association. On the more restricted and favourable sites, such as river banks, lake shores and drumlinized till uplands where conditions of soil texture and drainage are optimum, communities of trembling aspen, white spruce, balsam fir, black spruce, balsam poplar and white birch are found. Such mixedwood types tend to develop a strong shrub understorey, making it difficult to solve the problem of natural softwood regeneration. In the eastern portions there is some presence of eastern white cedar or tamarack in low positions, each usually associated with black spruce. Areas of bog, muskeg and upland rock barren occur throughout, the latter condition aggravated by frequent fires. The streams are relatively slow-flowing in their meandering courses over the plateau, except to the south where descent is rapid to Lake Superior. Glacial advance from the north covered the Precambrian granites and the intrusives with a calcareous drift and the presence of balsam poplar and white spruce on some of the moulded, morainic loams and clays seems to be correlated with the considerable lime content of these materials. On such soils, gray luvisol profiles are usual. There are local areas of very calcareous soils supporting stands of stunted black spruce. The coarser outwash and terrace deposits are leached of their lime, and podzolization is more active in them. Peaty phase gleysols and gleyed humo-ferric podzols are found on the low areas. |
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B.9 |
Superior: The forest conditions of the Great Lakes - St. Lawrence Forest Region found on the east and west sides of Lake Superior do not extend north of the lake. A climate of greater severity would appear to be at least partly responsible for the generally boreal nature of this Section which lies along the north shore, roughly from Michipicoten westward to Thunder Bay. The forests are extremely variable, ranging from mixed types with luxuriant shrub undergrowth to floristically poor, single-dominant coniferous types. A relatively stable mixed forest of white spruce, balsam fir, white birch and trembling aspen is characteristic of the deep, medium-textured valley soils. On till slopes and the tops of low hills, the same association of species is found but with the birch more prominent and some black spruce also appearing. Here the red-berried showy mountain ash is conspicuous as a tall shrub or small tree. The higher, more rocky elevations, and the coarser materials in the valleys bear jack pine and white birch, with black spruce of poor form. Some of the imperfectly drained, ponded silts and fine sands of the lowlands produce exceptionally fine pulpwood stands of black spruce, and yields on such soils equal the best of eastern Canada. Tamarack or eastern white cedar are usual companions of black spruce on the wet soils. The Section has been subjected to severe burning which has everywhere favoured an increase in the proportion of trembling aspen, white birch and pine (Pinus spp.). There is a limited occurrence of species from the Great Lakes - St. Lawrence Forest Region, with eastern white pine and red pine particularly evident on the terraces in the central portion between Lake Nipigon and Lake Superior. Also, in the river valleys there is some black ash, and in the eastern districts outliers of sugar maple and yellow birch occupy favourable hilltop positions. For the most part the topography is rough to rugged on the highlands, with steeply rising basaltic trap rock and associated talus slopes a striking physiographic feature. Between the hills, wide river valleys extend northward, and in these valleys as well as along the lake shore are found deep lacustrine, ponded, deltaic and terrace deposits from glacial Lake Algonquin and its predecessors. Above the old lake levels a thin glacial drift lies over the Precambrian granites, sedimentary and volcanic rocks and later basic intrusives. Rock outcrop at the surface is extensive both in the eastern and western parts. The soils are podzolized but not to the extent of infertility except on the coarsest deposits. |
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B.10 |
Nipigon: The Nipigon basin in which this Section lies is enclosed on three sides by the higher lands of the Central Plateau (B.8), and on the south by the Superior Section (B.9) to whose lowland forests its vegetation shows some similarity. In post-glacial times the basin was flooded by an arm or bay of Lake Warren or Lake Algonquin, and bedded lacustrine sands and clays were laid down both in the vicinity of the present lake and farther back in the valleys of the in-draining rivers. Subsequent crustal uplift has apparently separated these from similar deposits along the shore of Lake Superior. The simple topographic pattern is matched by a rather uniform forest, with black spruce dominating most of the communities. Exceptionally productive pure stands of this species clothe low rises, extending upslope into dry, open jack pine stands and downslope into fen types with tamarack. There are few open bog or muskeg types. In general, the forests of the north and northwest parts are poorer than those of the south and west. Areas with better-drained more favourable soil conditions support mixed stands of trembling aspen, white birch, black spruce, white spruce and balsam fir, the last-named pair of species achieving prominence particularly on sites protected from recurrent fire. On the islands of Lake Nipigon, red and eastern white pines occur in well-drained habitats. The topography is rolling though relief is somewhat low, with gentle rises on the valley sides to the higher portions of the divides. On the west side of the lake, younger Precambrian diabase and some sedimentary rocks form rugged exposures. Elsewhere the bedrock is composed of older Precambrian rocks, buried under the deep lake deposits in the basin or thinly covered with shallow, sandy morainic materials at higher elevations. In the latter position, thin soils over bedrock are common, and on deeper materials, shallow humo-ferric podzols with faint cementation in the subsoil occur. Organic accumulation is moderately deep on the poorly-drained lowlands. |
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B.11 |
Upper English River: The Section includes the upper drainage basin of the English River and part of the headwaters of the Albany River. It marks a transition between the Great Lakes - St. Lawrence forest to the south and the boreal forest to the north and east. The main body of the forest cover consists of black spruce and jack pine with mixtures of white spruce, balsam fir, trembling aspen and white birch. Jack pine stands are extensive on the dry sand plains and rocky uplands, and black spruce dominates in peat-filled depressions; mixtures of the two species are frequent in intermediate habitats. Tamarack is not abundant. Red and eastern white pines, as scattered individuls or isolated clumps, here reach their northern limits. In addition, yellow birch, largetooth aspen and eastern white cedar are reported. The strongly glaciated terrain has a rough, rolling topography with some plateau features, although relief is not great. Occassional morainic ridges, deep-soiled lacustrine flats and till plains occur, but in general the soil mantle is thin over the granitic Precambrian bedrock and in places it has been completely removed by the scouring of ice and water. Fires have been frequent, contributing to erosion of thin-soiled uplands. Humo-ferric podzol profiles, where developed on the finer-textured surface materials, provide excellent conditions for tree growth, but large areas are covered by thin, coarse-textured soils over bedrock of poor potentiality for forest production. |
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B.12 |
Hamilton and Eagle Valleys: Certain of the river valleys along the eastern border of the Labrador plateau support a forest which in its richer composition and better quality of growth stands distinctly apart from the subarctic vegetation of the adjacent uplands. The largest part of this outlier of the southern boreal forest is in the valley of the Hamilton (recently named Churchill) River, 500 to 800 feet below the surface of the surrounding country. Other segments of the Section occur on the Kaipokok, Eagle, Hawke and Alexis rivers, just inside the forest-tundra transition (B.32). Conifers form the matrix of the forest cover, and the most prevalent species over the range of sites is black spruce which plays the role of pioneer invader after fire and participates in the more stable types as well. In pure stands, or mixed with balsam fir and white birch, it occupies the poorly-drained flats and the shallow soils of the upland slopes. On the deeper lowland soils where conditions for forest growth are more favourable, prominent associates of the black spruce are balsam fir, white spruce which here grows to a large size, white birch, balsam poplar and occupying the northern part of its range, trembling aspen. On elevated sandy terraces and on the upper slopes of the hills where transition is made to the subarctic forest, open lichen-woodland dominated by black spruce appears on the dry sites and closed coniferous forest of spruce-fir on the moist sites. Occasional small stands of pure white birch and trembling aspen mark areas of past disturbance by landslide or fire. Jack pine does not extend into this Section, and tamarack though present is not abundant. The lowland position, effecting an ameliorization of the climate, is one feature of the environment favouring tree growth. Another is the presence of fine-textured surface deposits -- derived in part at least from underlying metamorphosed Precambrian rocks or younger basic intrusives -- which fill the broad valley bottoms and stand as terrace materials beside the rivers and lakes. The poorer upland soils seem to have resulted from the weathering of a thin sandy till and to some extent from a breakdown in situ of the gneissic bedrock. Humo-ferric podzols are usual in the well-drained position, while on wetter sites there is extensive development of sedge-and-moss peat. |
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B.13a |
Northeastern Transition: This is a broad band of subarctic forest which extends across central Labrador and Quebec, bounded on the north by the extensive "hemi-arctic" or forest-tundra transition (B.32) and on the east and west by narrow coastal strips of the same Section. The southern boundary is marked by an abrupt decrease in the prevalence of open lichen-woodland and a commensurate increase in closed-canopy coniferous forest on mesic sites. The land is a patchwork of lakes and rivers, bogs, swamps and muskeg, with areas of upland barrens and of forest, the characteristic form of the latter being the open, park-like woodland of black spruce with an associated ground cover of light coloured lichens. Closed forest stands are less common, although they do appear -- dominated by the ubiquitous black spruce -- where sites are of the moist, seepage type, as on mid-slopes and in shallow peaty draws. Species associating to some extent with black spruce in upland types on the less acidic and better drained soils are balsam fir and white spruce, the latter usually conspicuous in its sporadic occurrence due to a taller growth form than the other conifers. On the lowlands, where muskeg and bog stretch for miles, an open wet woodland type of black spruce is developed particularly on acidic geological materials. Strips of tamarack frame the lakes and water courses, or form strings in fens on calcareous substrata. Jack pine is confined to the southwestern half of the Section, trembling aspen is uncommon except along the southern boundary, balsam poplar occurs infrequently along streams, and white birch has a limited abundance on the upper slopes of hills, particularly in the south. The topography varies from flat to rolling, and though there are some quite rugged places, the relief is generally low. The geological foundation is of acid Precambrian rock, but a central strip of the Section, bordering on the Koksoak River, is underlain with altered sedimentary rocks on which a somewhat richer forest flora is found. Sandy to silty-clay glacial drift blankets the surface, drumlinized or thin over bedrock on the uplands, and deeper in terrace or outwash deposits in the valleys. Hummo-ferric podzols, dystric brunisols, gleysols, regosols and peats are present, and permafrost is a common ground feature over much of the area. |
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B.l3b |
Fort George: East of James Bay, in the area surrounding Sakami Lake and the lower Fort George River, lies a till-covered lowland with a gradual upward slope to the east. There is here, in general, a better forest cover than in the adjacent Northeastern Transition Section (B.13a), and extensive areas on both upland and lowland are clothed with open or closed stands of conifers. North of the Fort George River the jack pine is abundant on low, stony morainic ridges, while black spruce with an undergrowth of dwarf shrubs occupies the shallow organic soils of the intervening clay-filled depressions. Southward the uplands are more hilly, bearing open lichen-floored stands of black spruce with some white spruce and balsam fir. There are large areas of muskeg and open bog. The bedrock is largely composed of Precambrian granites and gneisses, with limited inclusions of schists, greenstone and quartzitic rock. It is overlain by a mantle of glacial drift, commonly moulded into drumlin landforms or, especially in the western two thirds, re-sorted by water action due to marine submergence. Rock outcrop is a prominent feature on the higher lands. Although the soils have not been investigated, hummo-ferric podzol and dystric brunisol profiles are to be expected on the well-drained uplands. |
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B.14 |
Lower English River: This Section includes that portion of the English River drainage area which at one time was under the influence of glacial Lake Agassiz. It is bounded to the south by the Great Lakes - St. Lawrence forest, on the west by the main basin of Lake Agassiz in the Manitoba Lowlands Section (B.15), and on the north and east by strongly glaciated Precambrian uplands. Mixed stands of trembling aspen, balsam poplar and white spruce provide the chief forest cover on the well-drained sites. Other common boreal species, balsam fir, white birch and jack pine, are also present -- the pine frequenting the sandier soils as is usual but also extending to clay and silt soils after fire. Shallow bogs are occupied by black spruce and tamarack. Eastern white pine and red pine from the adjacent Great Lakes - St. Lawrence forest have a limited presence on the rocky parts of the river banks as well as on lake shores and sand ridges. Green ash, white elm and bur oak are found also on riverine sites, apparently intrusives from the neighboring sections to the west and southwest. The post-glacial deposition of lacustrine materials produced a rather low relief in the area. However, the levelness of the stratified sand-and-clay surface deposits is somewhat relieved by occasional features of higher relief such as morainic ridges, rock outcrop and fluvial terraces. |
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B.15 |
Manitoba Lowlands: Included here is the forested area within the low, level basin of south-central Manitoba, bounded on the west by the Cretaceous escarpment and on the north and east by the shallowly mantled rock outcrop of the Precambrian Shield. Southward the Section comes in contact with the Aspen-Oak forest (B.16), the boundary between the two following the distribution limits of the boreal conifers. The prevailing vegetation on the flat, poorly-drained land consists of forest patches of black spruce and tamarack, with intervening swamps and meadows. Good stands of white spruce, trembing aspen and balsam poplar, sometimes in mixture with balsam fir and white birch, occur on the better-drained alluvial strips bordering rivers and creeks. In the central interlake area, the effects of repeated fires and poor sites (shallow, limestone soils) are reflected in stands of scrubby, worthless aspen -- these constituting a major problem so far as land use is concerned. Low ridges throughout are generally forested with jack pine or trembling aspen, though in the southern parts bur oak is common on such sites. Also present locally are white elm, green ash, Manitoba maple and eastern white cedar. The underlying bedrock is Palaeozoic limestone, and the overlying beds are mainly lacustrine clays deposited in glacial Lake Agassiz or modified tills. Conspicuous ridges of sand and gravel mark beaches formed at successive levels as the post-glacial lake drained, and characteristic of the old lake bottom is a succession of low, narrow, parallel rises with swampy depressions between. The influence of the limestone parent materials can be seen in the soils which tend toward humic gleysol and organic (peat) profiles. In areas long under forest, shallow gray luvisol profiles have developed on this highly calcareous substratum. |
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B.16 |
Aspen - Oak: In west-central Canada, the southern edge of the boreal forest meets the prairie on a crescentic front which extends from the International Boundary in Manitoba to central Alberta and the foothills of the Rocky Mountains. The deciduous element of the boreal forest extends into this broad transition zone beyond the conifers, forming continuous closed forest where local conditions are suitable, or groveland where elements of the prairie are intermixed. The front along which the two major formations meet is not static and at present the forest appears to be encroaching on the grassland (as it is also in the forest-prairie ecotone of interior British Columbia). While climatic fluctuations, past and present, are doubtless reflected in the vegetational shift, more direct importance may be attached to recent elimination of prairie fires and to reduction of grazing pressure. The southeastern portion of this transition zone is placed in the present Section. Trembing aspen is the prevalent species, occurring in the prairie proper as small patches of bushy trees ringing wet depressions, and as continuous good-growth stands along the northern boundary. Balsam poplar is found locally throughout, usually in the moister locations. Bur oak is conspicuous along the rivers and on such suitable sites as shallow dry soils and south or west slopes, but in general its distribution is sporadic within the matrix of the dominant poplar vegetation. On alluvial soils white elm is a common species, growing to a large size and reaching the western limit of the Section with no marked falling off of growth. With it are associated green ash, Manitoba maple, eastern cottonwood, and occasionally, in the southeast, basswood and black ash. The topography is varied from flat or undulating on the eastern side where influenced by the horizontally bedded Palaeozoic limestones and Lake Agassiz deposits, to rolling or rough on the morainic uplands of the central Cretaceous escarpment. Farther westward the terrain consists of a complex of old lake basins and glacial landforms. Soil development is to black chernozem profiles under the influence of hardwood cover on well-drained and poorly-drained sites, respectively. |
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B.17 |
Aspen Grove: The western portion of the forest-grassland transition, very similar to the eastern (B.16), is covered by this Section. To a large extent it coincides with the black and dark gray chernozem soil zones of Saskatchewan and Alberta. Outliers are recognized within the prairie proper as on the Cypress Hills in southewestern Saskatchewan, and also within the forestland of the north where limited areas of grassland occur in the Peace River country. Only trembing aspen is abundant in the natural stands. Balsam poplar is frequently present on moist lowlands, and occasionally it is also prominent on uplands after fire. White birch has a sporadic distribution but is usually found only on rough, borken land. There is a clear gradation in the heights reached by mature stands of trembing aspen from forest to prairie, the good growth attained in continuous stands to the north falling off to the low bluffs and patches in depressions and around sloughs in the south. River valleys traversing the eastern part of the Section in Saskatchewan and Manitoba support scattered stands of eastern cottonwood, green ash and Manitoba maple. The topography is variable but generally rolling. Surface materials are deep tills and glacio-lacustrine deposits, mainly of loam to clay loam texture and moderately calcareous. Black chernozem profiles are predominant, though signs of podzolic degradation in the form of dark gray chernozem profiles can be recognized under the aspen stands. Interspersed with the aspen bluffs in the original vegetation were prairie and meadow patches, but most of these have disappeared today under the advance of agriculture. |
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B.18a |
Mixedwood: Extending from southwestern Manitoba to northeastern British Columbia and adjacent District of Mackenzie is a large and important forest area. It is roughly coincident with that part of the Cretaceous Upland north of the aspen and aspen-oak woodland, and is recognized by the appearance in abundance of the needle-leaved conifers. It is bounded on the northeast by the more level Palaeozoic and Precambrian lowlands and on the west by the appearance of Cordilleran forest elements, particularly lodgepole pine. Along this latter boundary, the forest is broken up by patches of grassland and aspen groves, as well as by lodgepole pine outliers of the Lower Foothills Section (B.19a). A related northwestern part (B.18b), described in the following Section, is climatically more severe than the main body of the area here being considered, and balsam fir is absent from it. The characteristic forest association of the well-drained uplands is, as the name implies, a mixture in varying proportions of trembling aspen and balsam poplar, white and Alaska birches, white spruce and balsam fir, the last two species especially prominent in old stands. The cover type of greatest areal extent is the trembling aspen, a result of the ability of this species to regenerate readily following disturbance. In addition to its usual dominance on sandy areas, jack pine enters into the forest composition on the drier till soils, and mixes with black spruce on the plateau-like tops of the higher hills. Lower positions and the upper water-catchment areas develop black spruce and tamarack muskeg in which, however, the accumulation of peat is not deep. There is a minor occurrence of white elm, green ash, Manitoba maple and bur oak along the edges of the Section, noticeably in the southeast. The relief of the area is not extreme except locally in the eastern part. It is chiefly the result of pre-glacial erosion of the soft bedrock shales, which produced such features as the Cretaceous escarpment and associated hills in the vicinity of the Manitoba-Saskatchewan border, and the Missouri Coteau farther to the west. Subsequent glaciation modified the landscape, resulting in the present topography characterized by rolling morainic deposits on the uplands and smoother glacio-lacustrine deposits on the lowlands. The characteristic soil development is to the gray luvisol rather than podzolic profiles. |
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B.18b |
Hay River: This Section represents the northern extension of the mixedwood forest, somewhat modified by a more rigorous climate (colder and drier) and a more level terrain than obtains in the previous Section to the south and east. It is in contact with the riverine forests of the Peace and Slave rivers on the east, with the upper Liard on the west and with the lowlands of Great Slave Lake and the Mackenzie River on the north, and it encloses an outlier of the Lower Foothills Section (B.19a) on the Caribou Hills. The qulity of the forest growth is not as good as that to the south, and the abundance of white spruce in mixture with trembling aspen is less. Black spruce covers a large part of the land, commonly forming stands on the plateau-like uplands as well as in the lowland habitats where it is usually found. Jack pine is abundant on the eastern side of the Section, less so in the central and western parts. Along the western boundary there is a limited distribution of lodgepole pine. Shaly and sandy Cretaceous sedimentary rock underlies most of the Section, though in the escarpment area on the north and east the bedrock is of Devonian age and is largely limestone. Glacial advance over the latter formations incorporated a high proportion of calcareous material in the surface drift, with the result that soil profiles are frequently high in lime and hence shallowly leached. |
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B.19a |
Lower Foothills: In the foothills of the Rocky Mountains, and at low elevations in the front ranges, a transition forest between Boreal and Subalpine Forest Regions is found. The extensive eastern part of this forest ecotone covers low hills and plateaus between 4,000 and 3,000 feet in elevation in the south, descending to about 2,500 feet farther in the north. Three small outliers have been identified beyond its eastern boundary; one on the Caribou Hills (northern Alberta), a second centrally located on the Pelican Mountains, and the third on the Cypress Hills (extreme southeast Alberta and adjacent Saskatchewan). The distinctive tree species is the lodgepole pine which, with trembing aspen and balsam poplar, has assumed a dominant position over much of the area in the wake of fire. In older forest stands white spruce is an important constituent and black spruce is frequently present too. White birch and tamarack have scattered representation and with the above species on appropriate well-drained or poorly-drained sites, respectively. Both balsam fir and alpine fir are common locally in the main body of the Section, although the over-all importance of these species in the forests is small. The topography is rolling, with some plateau areas among low to high rounded hills. The main rivers flow eastward in broad incised valleys. Glaciation from the east and to a lesser extent from the Cordilleran region covered the Mesozoic sedimentary rocks with a drift of variable composition, on which the usual soil development of upland sites is to gray luvisol profiles or related podzolic types depending on the calcareousness of the parent materials. |
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B.19b |
Northern Foothills: The Section fronts the Rocky Mountains in the Peace River district of northeastern British Columbia, and extends an arm around the north side of the main range to the Kechika drainage and the upper Rocky Mountain trench. Its altitudinal range extends from approximately 5,000 feet, where it begins to merge with the alpine tundra, to its contact with the forests of the upper Liard at about 3,000 feet, or lower in the interior mountain valleys. In position relative to the alpine tundra which it partly surrounds, the Section occupies a zone comparable to that of the subalpine forests farther south. However, no Engelmann spruce is present here. The dominating trees are white spruce, black spruce and lodgepole pine, in mixture forming a variety of types. The black spruce-white spruce-pine type is distinctive of the high plateaus, though it also occupies areas of low relief on fine-textured soils. In stands predominantly of white spruce the alpine fir is a common associate, its relative abundance increasing up the slopes of the mountains. The broadleaved trees are not abundant, although some white birch varieties are scattered through upland stands, trembling aspen appears on south-facing slopes, and balsam poplar is present on lowland alluvium. Black spruce occupies the usual lowland niche on organic soils. In general the forest stands are rather patchy and open, and their productivity is not high. The topography varies from level on the riverine flats and terraces to rolling and strongly dissected on the hills and lower mountain slopes. Some eutric brunisol soils have been reported on calcareous alluvial sites, and gray luvisol soils on the upland tills. Regosols are common on colluvial materials, and peats in the poorly-drained positions. |
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B.19c |
Upper Foothills: This long, narrow strip of forestland extends parallel to the front range of the Rocky Mountains, from the aspen parkland of southern Alberta to the more alpine environment of northeastern British Columbia where it merges with the Northern Foothills Section (B.19b). It lies adjacent to and above the Lower Foothills Section (B.19a), and comprises the western part of the transition from boreal to subalpine forest. The foothills reach as high as 6,000 feet in altitude and are forested to their summits with conifers. A distinctive feature in comparison with the lower-lying forests to the east is the relative scarcity of mixedwood stands, for trembling aspen, balsam poplar and white birch are only sparsely represented. In addition to lodgepole pine, which is predominant, a major species is the typical white spruce rather than the Engelmann-white spruce complex which occupies the same altitudinal zone in subalpine forests. Black spruce is a frequent constituent of the forests north of the Red Deer River, but its occurrence is sporadic to the south. Alpine fir is somewhat less prevalent than in the neighboring mountains, while tamarack is scattered in distribution and rare at the higher altitudes. The Section is typified by high rounded hills and deep valleys. The uplifted and folded Mesozoic and late Palaeozoic sediments which form the bedrock are overlain by glacial deposits and colluvial material, and the mature soils show podzolic or gray luvisol development. |
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B.20 |
Upper Churchill: This Section in west-central Saskatchewan occupies an area of low relief, mostly below the 1,500-foot contour, bounded by the Precambrian Shield on the north and the Saskatchewan uplands of the south. Extensive stands of jack pine occupy the sand plains and low ridges, while intervening poorly-drained areas are forested with black spruce and tamarack. White spruce and trembling aspen are of less importance here than on the upland tills of the Mixedwood Section (B.18a) to the south, though both species, and also balsam poplar, are well represented where drainage conditions are favourable. Balsam fir and white birch are present but not abundant. Large areas of swamp, bog and muskeg are common. The area was occupied by Lake Hyper-Churchill at an early stage in the retreat of the last continental glacier, hence the flat or undulating surface. The sandy nature of the lacustrine and till deposits has possibly been inherited, in part at least, from a thin basal sandstone on the Precambrian basement at the north side of the Section, even though the main bedrock is dolomite or limestone of Devonian age. Soil profiles under jack pine forest on the sandy tills and lacustrine plains are strongly leached, the whiteness of the eluviated horizon (Ae) showing up strikingly wherever the surface humus is removed as along bush trails. On heavier materials, for example on some of the modified tills or banded lacustrine deposits, gray luvisol profiles have developed in association with white spruce and trembling aspen forests. |
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B.21 |
Nelson River: The Section includes a strip of land lying along the east shore of Lake Winnipeg and, northward, the clay belt surrounding the upper Nelson River in central Manitoba. It is bounded geographically by the lakes of the Palaeozoic lowlands on the west, and by the appearance of abundant Precambrian rock outcrop on the east and on the north. The northern boundary is also marked by a change from southern closed forest to open subarctic forest. Stands of black spruce make up a large part of the forest cover, but proximity to the numerous and extensive swamps that lie back from the rivers is reflected in a restriction of growth. Where drainage is better as along the sides of rivers, on islands or on low ridges, good stands of white spruce with some balsam poplar, white birch, trembling aspen, and balsam fir are customary, with possibly more trembling aspen and balsam poplar under such conditions on the east side of Lake Winnepeg. Extensive and repeated fires have, however, fragmented all the forest cover, and large areas support small-growth trembling aspen, white birch, and scattered white and black spruce, or jack pine and trembling aspen, or grassy scrub on rocky barrens. Tamarack is present with black spruce in the swamps; isolated occurrences of green ash and Manitoba maple are reported on some of the river banks, and there is a little bur oak in the southern arm of the Section. The area was covered by glacial Lake Agassiz, and the consequent deposition of lacustrine clays and sands has had the effect of levelling what was formerly an irregular and rolling Precambrian surface. The lacustrine deposits are shallow on the rocky uplands and deeper in the valleys, extending back along the latter considerable distances from the present-day lakes. On the well-drained materials, podzolic profiles normally develop. Gleysols are typical of poorly-drained slopes, while moss and woody peat characterize the spruce-tamarack muskegs. |
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B.22a |
Northern Coniferous: On the southwestern part of the Precambrian Shield, from western Ontario to western Saskatchewan, is a Section where climatic conditions allow reasonable tree growth and the development of closed forests wherever depth of soils is adequate. It is bounded on the north by the subarctic open forest, and is divided into a western and an eastern part by the northward extension of the Lake Agassiz lowlands (Nelson River Section, B.21). Black spruce is the predominant tree, forming stands on the thin soils of the uplands as well as the poorly-drained lowlands, and associated on these two positions with jack pine and tamarack, respectively. Frequent fires have favoured the spread of jack pine and are probably responsible also for the general though scattered representation of white birch over the majority of sites. In river valleys, around some of the lakes and on south-facing slopes, where more favourable conditions of soil and local climate obtain, white spruce, balsam fir, trembling aspen and balsam poplar form mixed stands of good growth. The area is within a region where glaciation was intense, and the resulting relief is irregular, with rocky parallel ridges separating poorly drained depressions and innumerable narrow lakes. Drift deposits on the uplands are thin in some places and absent in others where rock barrens of Precambrian granites and gneisses are exposed. The deeper drift of slopes and valleys shows humo-ferric podzol profile development, while the less well-drained areas are peat-filled. |
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B.22b |
Athabasca South: The Section comprises a broad lowland in northern Saskatchewan and northeastern Alberta, bounded by Lake Athabasca and the subarctic open woodland on the north, and by the preceding Section on the south. Sandy soils derived by glacial action from the underlying sandstones (probably late Precambrian) have favoured forests of jack pine which are frequently park-like in structure due to rigorous climatic conditions and the frequency of fires. Moister sandy flats and the finer-textured soils bear black spruce and tamarack. Trembling aspen, balsam poplar and white spruce are uncommon except along river valleys and lake shores where good growth is made. In the southern parts, balsam fir is associated with these last-named species. Relief is generally low, relieved only by deeply cut river valleys. Near Lake Athabasca there are wide areas of unstabilized dune sand, and farther south some remarkable drumlin fields. Ridges of morainic materials and of stratified drift contribute to the rolling topography. Humo-ferric podzols, gleysols and organic (peat) soils are present. |
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B.23a |
Upper Mackenzie: The Section is roughly V-shaped, with the arms extending upstream from the confluence of the Liard and Mackenzie rivers to the Fort Nelson River and the lower Peace River, respectively, and with the elongated apex reaching downstream to Norman Wells. It includes a large part of the riverine forest of the Mackenzie drainage, and because in the north the valley flood-plain environment is much more favourable for tree growth than that of the uplands, it coincides with some of the best timber producing land in the northwest. White spruce and balsam poplar form the main cover types on alluvial flats bordering the rivers. Few other species participate in forests of this particular site though balsam fir, and the white and Alaska birches are prominent south of Lake Athabasca. On the benches above the flood plains, extending back variable distances to the highlands, there is an entirely different forest pattern. Large areas of sandy soils are occupied by jack and lodgepole pines, trembling aspen and , in the moist to wet positions, by black spruce and tamarack. In contrast to its importance on the riverside alluvium, white spruce plas a minor role in the upland communities. Excellent merchantable stands of white spruce grow along the flood plains of the Liard and lower Peace rivers, with possibly more balsam poplar intermixed with the spruce in the former than in the latter locality. Scattered lodgepole pine accompanies trembing aspen, white birch and white spruce on rocky till slopes and sandy terraces above the Liard, but on the highlands bordering the Slave River jack pine is the usual associate of these latter species. Within the northernmost strip of the Section, adjacent to the Mackenzie River, the abundance of balsam poplar and trembling aspen decreases from south to north. Here the benchlands, where forested, bear mixtures of white birch and white spruce which grow well wherever the permafrost table is sufficiently deep to allow adequate rooting. Black spruce stands are common on slopes as well as in the permafrost muskegs that commonly border the river flood plains. Topographic conditions are everywhere very similar, the alluvial flats being bordered by low benchlands and terraces which in turn give way to undulating or rolling uplands with isolated ridges and low hills. The bedrock of Devonian and Cretaceous age is mostly buried deeply under glacial tills or more recently deposited lacustrine and alluvial materials. From south to north the frequency of frozen ground as a normal condition of the forest substratum increases, and though the full significance of this phenomenon to site productivity is not yet understood, it is believed to be of considerable importance. Gray luvisols and eutric brunisols are developed on well-drained sites in the southern parts, though immature profiles are more usual in alluvium. Northward the presence of permanent ground frost prevents soil profile development. There are large areas of swamp and peat. |
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B.23b |
Lower Mackenzie: The lower part of the valley of the Mackenzie, from about the Great Bear River to the delta, defines the area of this Section. It is enclosed, east and west by upland subarctic woodland and by transitional forest-tundra. The dominant environmental feature is permafrost, which underlies all soils at depths depending on texture and topographic position, moistness of site and vegetative cover. Where the permafrost table is not high, as on some of the well-drained benchlands, white spruce attains sawlog size, but on fine-textured alluvium the growth of trees is poor, and scrubby types of forest composed of willows and alder with stunted white spruce and black spruce prevail. Trembling aspen and balsam poplar are not abundant, the usual position of these two species on upland sites being taken over by Alaska birch. There are great expanses of stunted black spruce on the more level, poorly-drained terrain, but tamarack -- a common associate on such sites farther south -- is not present. In general, through the Section as a whole, there is far more nonforested than forested land. The underlying horizontally bedded sedimentary rocks, of Cretaceous age in the west (Peel Plateau) and Devonian age in the eastern part, control the low relief in this broad, relatively level plain. The entire area was glaciated, and the bedrock is covered with drift and recent alluvial deposits, the latter being calcareous. The influence of ground frost, seen in such common features of the uplands as solifluction terraces and patterned ground (polygons), is also reflected within the soils where little evidence of profile development can be seen. |
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B.24 |
Upper Liard: An irregular area spread along the boundary between the Yukon Territory and British Columbia, this Section includes a large part of the land draining to the Liard and Fort Nelson rivers north of the Northern Foothills Section (B.19b), with whose forests it has much in common. It is characterized by level landforms above the river courses, supporting stands of lodgepole pine, black spruce, white spruce and trembling aspen. On the north and west sides it comes from in contact with the sparsely-forested Yukon plateau, and on the east with the more productive Lower Mackenzie and Hay River sections (B.23b, B.18b), neither of the latter containing any quantity of lodgepole pine. Good forest growth is found here, particularly on soils of the alluvial flats. The dominant trees in the latter position are white spruce and balsam poplar, the two species forming pure stands more frequently than mixtures. Above the river flood plains, black spruce and lodgepole pine form extensive pure and mixed stands. White spruce grows locally with trembling aspen and white birch on the most favourable sites, and with alpine fir as the treeline is approached on the higher lands. Past fires are responsible for an abundance of lodgepole pine stands, particularly on the sandy terraces which border the Liard in the western part of the Section. Black spruce and tamarack occur in low positions, although the former species is also prominent on upland fine-textured soils and on shaded slopes where lodgepole pine is its common associate. The topography is that of a plain dissected by wide river valleys, these bordered by broad terraces which in turn give way to rolling uplands with low hills. The soil materials are derived from glacial, colluvial and alluvial deposits. Perennially frozen ground is not common, and the northwestern part of the Section appears to be climatically the most favourable forest-growing area in the Yukon Territory. |
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B.25 |
Stikine Plateau: Included here are the forested parts of the area between the Cassiar and Coast mountains in northwestern British Columbia. The forest cover is scant and largely confined to the valleys; the boundaries of the Section are set altitudinally by the change from forest to alpine tundra on the mountain slopes. An open mixture of trembling aspen, white spruce and lodgepole pine, interspersed with grassy areas, constitutes the prevailing vegetation pattern. Alaska birch has a scattered representation, black cottonwood appears on the river banks, and there is some alpine fir toward the treeline. Engelmann spruce, present in the Sections to the south, does not reach this area. Black spruce is not a prominent tree and apparently tamarack is absent. The plateau is composed of several tablelands, separated by broad valleys and deeply cut at the margins by smaller streams. The bedrock is chiefly sediments with some lava, over which lies an uneven cover of glacial debris on the uplands, and of alluvial and colluvial deposits in the valleys. |
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B.26a |
Dawson: In the Yukon Territory the forests are largely confined to the plateau region of the south and west, a dissected basin of sedimentary and intrusive rocks ringed by high mountains. The major rivers, entrenched one to two thousand feet below the hilltops of the rugged upland surface, occupy narrow, steep-sided valleys. Because the plateau lies in a rain shadow, glaciation was incomplete during the Pleistocene era. One part of the unglaciated area, south of the Ogilvie Mountains and surrounding the Dawson Range and the Yukon River valley, is the subject of this description. Alluvial flats are not common landforms here, hence the mixture of white spruce and balsam poplar so typical of the broad river valleys east and south of the Yukon Territory is not a prominent forest type. The chief forest habitat, the valley slope, bears stands of white spruce (some of the Porsild variety) either pure or mixed with small groves of Alaska birch or with trembling aspen. These hardwood species, though maintained on many different sites by fires, are best suited to the warmer local climates, and trembling aspen in particular favours grassy dry hilltops and steep south-facing slopes where ground frost is minimal. The most favourable white spruce site is on lower slopes, high enough to be above the valley floors where cold air collects. In the valley bottom position, as well as on exposed uplands and in boggy areas, where the permafrost table is high, stunted stands of black spruce and white spruce are usual. On levees adjacent to the rivers, growth of the white spruce is potentially good although the usual vegetation is dense alder and willow scrub. On upland slopes there is some alpine fir associated with the black and white spruces, and at 3,000 to 4,000 feet altitude the stunted forest changes to dwarf birch and then to an alpine tundra. Tamarack is not present in this Section, and lodgepole pine has only a scattered distribution. Surface deposits are mainly residual, due to breakdown in situ of the underlying Precambrian and Tertiary rock. There has been a significant accumulation of volcanic ash in some places, and this apparently has some adverse effects on the rooting of trees. The soils are of variable petrography, but in general the effects of parent material are masked by the prevailing youthfulness of profile development. Some shallow, eutric brunisols have been noted. |
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B.26b |
Central Yukon: The upper drainage of the Yukon River, centred around Whitehorse in the south of the Territory, comprises a Forest Section with many similarities to the preceding one. The area is irregular in shape and encloses numerous mountain chains from the Pelly and Big Salmon ranges on the east to the Coast Range on the southwest. The best forests are found on protected lowlands, with growth grading off as altitude increases. White spruce grows to saw-timber size on lower slopes where the surface mantle is stable, but above approximately 3,000 feet altitude its growth is restricted. On the uplands it associates with alpine fir which however ascends above it to the treeline at 4,000 to 5,000 feet. Interspersed with islands of park-like white spruce, willow and trembling aspen on the mountain slopes are patches of grassland and, in areas of soil instability, erosional barrens. Trembling aspen appears to be sensitive to aspect, and stands of open structure and flat-topped form usually occupy the south and west-facing slopes at moderate altitudes. In the valleys, on water-modified tills and coarse terrace materials, lodgepole pine and white spruce share dominance in closed or open but rarely tall stands. Trembling aspen is a frequent associate of the conifers, and the mixed spruce-pine-aspen type is common here as in other Sections of the northwest. Lodgepole pine is particularly prevalent on dry sandy soils in the southeastern part of the Section; westward and to the north it diminishes and finally disappears as a member of the forest communities. Tamarack too is mostly limited to the eastern side. Black spruce ranges throughout on organic soils of the leveler land-forms where either texture of mineral soil or frozen ground maintain a high water table. It is frequently joined on such sites by white spruce, and in this area the ecological difference between the two species is somewhat blurred. There is only a limited development of the alluvial flood-plain site and hence not much of the productive riverine spruce-poplar type so prominent along the Peace, Liard and Mackenzie rivers. Throughout the Section there is evidence of recent strong glaciation, and the soils are predominantly of unmodified or waterworked glacial drift. In the river valleys, the modified materials tend to be somewhat coarser in texture than those present farther downstream in the more western Sections. Soil development is generally weak, due to the youthfulness of the surface materials and to the dry climate. Eutric brunisols are usual but gray luvisol and eluviated dark brown chernozem profiles also occur. The rooting depth of trees and other plants is in some areas affected by layers of volcanic ash in the soils, and in other places, particularly northward, by permanently frozen ground. |
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B.26c |
Eastern Yukon: The eastern part of the Yukon plateau, bounded on the north and east by the Ogilvie and the Selwyn mountains, respectively, and on the south by the Liard and Stikine plateaus, is somewhat higher and colder than the Section to the west. The effects are seen in the common occurrence of forestless barrens as well as in the general distribution of perenially frozen ground. Aspect has a significant influence on forest vegetation, with south and west slopes favourable to mixed stands of white spruce, trembing aspen, Alaska and Kenai birches but with the north and east slopes frequently non-forested. As in central Yukon, alpine fir occupies suitable sites on the higher slopes, either associated with a white spruce-birch-black spruce type, or alone forming a scrub growth at timberline (usually below 5,000 feet altitude). On lower slopes and valley terraces the forest cover is dominated by white spruce, lodgepole pine and trembling aspen in the southern parts, and by white spruce, birch and black spruce northward and in the mountains. The black spruce also grows in bogs and on permafrost slopes, accompanied on the former site by tamarack and on the latter by Alaska birch. Flood plains are generally narrow in the sharply cut valleys and as a result there is a low representation of balsam poplar forest, Locally, patches of well-formed balsam poplar and white spruce do occur on alluvium, backed by white spruce and white birch on the higher terraces. The entire area was strongly glaciated, and the surface mantle consists of glacial drift, much of it calcareous. On this, as on the limited alluvial deposits of the valleys, soil profile development is poorly defined. Organic (peat) soils are extensively developed due to the widespread interruption of internal drainage by ground frost. |
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B.26d |
Kluane: The Section comprises a narrow strip of forestland at the southwestern corner of the Yukon plateau, fronting the very high St. Elias Mountains in whose rain shadow it lies. In this dry, cold climate, the vegetation has a park-like appearance, and even in the river valleys the forest stands are rarely dense and closed. Grassy openings, alternating with groves of trees, are apparently indicative of locally warm, unfrozen soils. The best forests are the river valley associations of white spruce, trembling aspen and balsam poplar. The spruce does not attain the growth expected of such sites in adjacent Sections to the south and east, and this indicates the poor forest potential of the area. On the benchlands of the valleys the types are composed of white spruce, trembling aspen and Alaska birch. There is no lodgepole pine in the Section, and neither black spruce nor tamarack are prominent species. On peat lands the white and black spruces appear to be ecologically interchangeable. Upland slopes bear an open forest of white spruce with an undergrowth of low willows and birches, giving way to shrubby or grassy "barrens" at about 4,500 feet altitude. The Section comprises broad valleys flanked by hills, mostly rather low, but with some (as at Kluane) rising to an altitude of 6,000 feet. The area was heavily glaciated very recently, and some glaciers still remain. |
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B.27 |
Northwestern Transition: In western Canada the closed coniferous forest passes northward into a zone of open subarctic woodland which extends from Hudson Bay almost to the delta of the Mackenzie River, and includes the areas around Great Bear Lake, east Great Slave Lake, Wollaston Lake and Southern Indian Lake. It in turn gives way to mixed forest-tundra along a boundary running roughly northwest-southeast from Arctic Red River to Churchill. In this forest fringe fronting the tundra, unfavourable climatic conditions, thin soils and frequent fires have combined to reduce the distribution, abundance and size of the tree species. Areas of bog, muskeg and barren rock are intermixed with open stands of dwarfed trees, although on local patches of sheltered, deep, frost-free soil the density and height growth of forest patches can be surprisingly good. Characteristic of the park-like coniferous stands on the upland sites is a ground cover of light-coloured, foliose lichens. The most abundant tree on all sites is black spruce, and with it on the well-drained soils grows white spruce. Other accompanying species are white birch and tamarack, the latter of increased importance in the more northerly parts of the Section. Jack pine is only common in the southern parts especially on sandy soils and uplands. Stunted trembling aspen and balsam poplar extend well toward the northern boundary. Balsam fir is not present; a contrast to its commonness in comparable Sections of the east side of Hudson Bay. Over most of the area the bedrock is of Precambrian granites and gneisses with many scattered irregular areas of sedimentary and volcanic rocks, but south and west of Great Bear Lake the Section extends onto Palaeozoic and Cretaceous sediments. A generally low relief, plus shallow depth of glacial till over bedrock, contributes to the prevalence of water-filled depressions, and vast stretches of the country appear to be almost as much lake as land. Eskers, till ridges and rock knobs are common surface forms. Ground frost is a usual feature of all but the coarsest-textured soils. |
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B.28a |
Grand Falls: This Section, occupying the plateau of central-northern Newfoundland, contains the greatest area of productive forestland in the province. To the south and west it is bounded by highland moss barrens, on the east by the poorer forests of the Avalon peninsula, and on the north by a narrow maritime strip \ differentiated by a contrasting prominence of white spruce. The forests are chiefly coniferous, dominated by balsam fir and black spruce. Regeneration of the black spruce has been favoured by a long fire history with the result that, at the present time, it is the predominant tree on the eastern side of the Section; balsam fir is more important to the west. Open black spruce stands on raw peat, and heath-covered fire barrens are common. White birch is of general though scattered distribution throughout, and small pure stands of the species are especially noticeable in the central and western parts. White spruce has a similarly widespread and scattered occurrence. Trembling aspen plays a pioneering role on some cut-over and burned areas, while balsam poplar is only occasionally seen. Formerly good stands of eastern white pine were in existence, but there is nothing much left of them now. The only red pine in Newfoundland is found here localized in a few areas. The topography is mainly that of a flat to gently rolling plain of low relief sloping to the northeast, with many bogs and muskegs, lakes and rivers, chief among the latter being the Exploits. The underlying strata are mostly Palaeozoic sediments with some intrusive rocks, and the derived glacial tills that cover the surface are relatively fertile. The soils are humo-ferric and ferro-humic podzols on the uplands, gleysols and organic soils (peats) on the lowlands. |
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B.28b |
Corner Brook: The Section embraces southwestern Newfoundland, from the coastal plain of St. George's Bay to the interior lowlands of the Humber River and Grand Lake. It is bounded north and eastward by the poorer forests and barren lands of the Northern Peninsula and the southern Long Range Mountains, respectively. The growth potential is good in this, the second largest area of productive forestland in Newfoundland. Balsam fir, the principal softwood species, grows very well here in association with black spruce and white spruce. Though conifers predominate, the district is characterized by small stands of deciduous trees in which white birch is a dominant and trembling aspen plays a lesser role. Eastern white pine, black ash, balsam poplar and yellow birch occur here and there as minor species, the yellow birch being distributed along the west coast southward from Corner Brook. Another characteristic of the Section is the abundance of mountain maple, a small tree or shrub which elsewhere in Newfoundland is rather inconspicuous. The upland terrain is rugged, contrasting with the flat valley bottoms and coastal strips. Palaeozoic sedimentary rocks underlie the area, and humo-ferric podzol profiles are usual in the overlying glacial drift. Climatic and soil conditions are evidently more favourable than in the adjacent Sections as attested both by the good height growth of the trees and by the marked similarity in forest composition to that of the Acadian Forest Region. |
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B.28c |
Anticosti The windswept island of Anticosti at the mouth of the St. Lawrence River supports a mixed forest of white spruce, balsam fir, black spruce and white birch. Trembling aspen and balsam poplar though present attain no importance in the various forest types. The height of mature trees is not great, possibly due to wind effects. A remarkable feature of the vegetation is the virtual absence of shrubs, and not even alders appear in the understorey of open stands. Burned areas apparently regenerate easily and almost immediately to white and black spruces and a large resident deer population is presently effecting changes in the forest composition by grazing and thereby eliminating balsam fir young growth. The bedrock of Anticosti is of Silurian and Ordovician limestone, and the calcareous surface detritus, modified over most of the island by marine submergence, is well known as a habitat of rare plants, particularly along the southern coast. |
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B.29 |
Northern Peninsula: The Long Range which forms the backbone of the Northern Peninsula of Newfoundland is practically treeless at the top (B.31 Section) but the slopes toward the Gulf of St. Lawrence and the Atlantic Ocean support good coniferous stands. At the northern tip of the peninsula the closed forest grades into open lichen-woodland of the forest-tundra transition, while the southern boundary of the Section is marked by a transition to the richer forests of the Humber Valley and Grand Lake. The principal trees are balsam fir, black spruce and white spruce. The balsam fir in particular attains very high population densities. The average growth potential is inferior to that of forests in the Grand Falls and Corner Brook Sections (B.28a, B.28b) but nevertheless high yields of pulpwood are obtained on well-drained sites, particularly on the western slope. The boreal hardwoods, trembling aspen and white birch, are of secondary importance even though the representation of white birch in the forests is apparently as high or higher here than in any other part of the province. Excepting only the Bonne Bay area, the Northern Peninsula Section contains no eastern white pine, in this differing from most other parts of Newfoundland. White spruce is a prominent tree of the maritime strip along the northern side of the island, but most of this area is nonforested rock barrens. The topography is relatively rugged over a variable bedrock. At the higher elevations Precambrian granites underlie shallow tills, or outcrop on the slopes, while at lower elevations the bedrock under a generally deeper drift is of Ordovician limestones and sandstones. Humo-ferric and ferro-humic podzols are usual, and there is extensive development of ericaceous and moss peat on poorly-drained lands. There are some large areas of sterile serpentine soils in the western part. Climatic conditions are rigorous, and exposure to fog and wind may be factors serving to limit height growth of trees on many sites. |
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B.30 |
Avalon: Included in this Section is the Avalon peninsula and the eastern mainland of Newfoundland. The south mainland boundary is formed by moss-and-heath barrens and the northern by a transition to the better pulpwood forests of the Grand Falls Section (B.28a). Throughout this cool and windy area the forests have been destroyed or badly decimated by fires and cultural practices, and the prevailing character of the vegetation today is that of a patchy though dense-growing young coniferous forest interrupted by extensive barrens. Balsam fir is the most abundant tree characterizing the forests of the Avalon peninsula and the adjacent mainland. Although it grows well in early life on good sites, heights in excess of 40 feet at maturity are rarely reached. Almost equally important is black spruce which either grows with balsam fir and white spruce on the better soils or dominates alone in stunted, slow-growing stands on the poorer upland sites. Black spruce is also prevalent as usual on the wet lowlands where it is frequently accompanied by tamarack. White spruce is numerically of small importance and is found chiefly along the coastline associated with balsam fir. The only important hardwood is white birch, common on north-facing slopes and in deep valleys; although on the better soils it forms occasional pure stands, it is more commonly associated there with blasam fir. Yellow birch grows locally in protected valleys and a limited amount of red maple occurs. Eastern white pine was at one time of considerable economic significance but it is becoming increasingly rare. The Section occupies a rolling plateau, underlain by late-Precambrian sedimentary and volcanic rocks. Inland, the area is studded with numerous lakes and ponds, and drainage is effected by many small but swift rivers. The soils developed on the thin drift over bedrock are nutrient-poor humo-ferric and ferro-humic podzols of youthful appearance. The cool, humid climate is favourable to the accumulation of peat in raised bogs, and approximately half of the terrain surface is covered by moss-and-heath bogland. Fires have undoubtedly contributed to the formation and maintenance of much of this nonforest vegetation. |
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B.31 |
Newfoundland - Labrador Barrens: The extensive areas of sparsely forested heath-and-moss barrens in south and central Newfoundland, on the upper levels of the Long Range in the Northern Peninsula, and in southeastern Labrador, are placed together in this Section. Though it is likely that there is considerable climatic variability between these different areas, the appearance of the vegetation is everywhere much the same, i.e., a stunted, open and patchy or sometimes continuous cover of black spruce and balsam fir, alternating with moss-and-heath barrens, rock outcrop and lakes, on a generally featureless, windswept terrain. There is a lesser percentage of nonforested barren land in the Labrador sector than elsewhere in the Section, for open lichen-woodlands dominated by black spruce are usual on the uplands. On the other hand, many upland areas and slopes on the island of Newfoundland are blanketed with moss bogs, a possible reflection of the high moisture surplus. The primary forest types of black spruce and balsam fir are often dense though usually dwarfed, indicating that conditions are suitable for establishment if not for later growth of the conifers. The presence of occasional good stands of trees on sheltered, well-drained morainic hillocks suggests that the generally poor forest growth is a result of wet, cold soils, and exposure to wind. Secondary species associating with the black spruce and balsam fir are white spruce and white birch, with tamarack on the wetter sites. The topography is locally rugged to mountainous but with large areas of low relief. The underlying bedrock is of variable Precambrian and Palaeozoic granites and sedimentary rocks. On the surface drift, organic (peat) soils are prominent, and on well-drained sites the profile developed is a humo-ferric podzol. |
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B.32 |
Forest - Tundra: The transitional zone between subarctic forest and tundra stretches across northen Canada from the Mackenzie Delta to James Bay, thence to Unagava Bay and the Atlantic Coast. Such a broad geographic range inevitably includes a great diversity of environments, but the over-riding influence of climatic severity has produced a similarity of vegetation structure throughout. This consists of a pattern of tundra "barrens" and patches of stunted forest, the latter usually but not exclusively along the shores of lakes and rivers and the former on the upland interfluves. The pattern shows a gradient change from south to north as forests shrink and tundra expands. The primary species are the two spruces (white and black) and tamarack, accompanied by alder and willow shrubs. Where the forest-tundra is under maritime influence as around Hudson Bay and along the Atlantic coast of Labrador, white spruce is usually the most prominent tree, particularly on the immediate coastal strip. Inland, black spruce and tamarack compose the bulk of the forest patches with the former species frequently assuming a shrubby "candelabrum" form as the treeline is approached. Pine (Pinus spp.) is absent, and balsam fir only rarely occurs in the Ungava area; the other boreal trees -- white birch, trembling aspen and balsam poplar are infrequent. In the forest-tundra ecotone the major controlling influence is climate, and the vegetation is an expression of such environmental features as exposure to wind, protection by snow, instability of soils under permafrost conditions, low air temperatures during the growing season and fire. Thus the general environment makes forest survival precarious and there is evidence that the treeline has fluctuated widely in the past. |
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B.33 |
Alpine Forest - Tundra: Between the Mackenzie lowlands and the mountains along the Yukon-Mackenzie boundary, and on the interior Porcupine Plain of northern Yukon, an altitudinal transition takes place from forest to alpine tundra analogous to the latitudinal transition in central and eastern Canada from forest to arctic tundra. Open, park-like stands of stunted white spruce, alternating with patches of grassy or shrubby vegetation, or with rocky barrens, are characteristic of the mountain slopes up to treeline at about 3,500 to 3,800 feet. On northern and eastern aspects the alpine fir is usual at the treeline transition to alpine tundra, and on the same aspects but at lower altitudes the black spruce has its greatest representation, either alone or mixed with white spruce. On more favourable sites, Alaskan birch is found with white spruce. Tamarack, trembling aspen and balsam poplar are infrequent constituents of the vegetation. At the southern edge, lodgepole pine is conspicuous on mountain slopes. |
This is a coniferous forest found on the mountain uplands in western Alberta and in British Columbia. The Region extends northward to the major divide separating the drainage of the Skeena, Nass, and Peace rivers on the south from the Stikine and Liard rivers on the north. The characteristic species are Engelmann spruce, alpine fir, and lodgepole pine. There is also a close relationship with the Boreal Forest Region, from which the black and white spruces and trembling aspen intrude. There is also some entry of interior Douglas-fir from the Montane Forest Region, of amabilis fir from the Coast Forest Region, and of western hemlock from the Columbia and Coast Forest Regions. Other occasional species are western larch, whitebark pine, and limber pine, and on more western ranges yellow cypress and mountain hemlock.
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Map Symbol |
TEMVEG |
Description from Map Legends of Rowe (1974)a |
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SA.1 |
East Slope Rockies: Covering the eastern slopes of the Rocky Mountains and the rugged adjacent foothills, from approximately 5,000 to 6,800 feet altitude, is a coniferous forest distinguished from that of the Upper Foothills Section (B.19c) by the presence of the Engelmann spruce-white spruce hybrid complex and at higher altitudes by Engelmann spruce alone. An important associated species is the lodgepole pine whose powers of prolific regeneration following fire have resulted in its replacing the spruce over great areas. With increasing elevation on the slopes, alpine fir becomes more important, particularly in the older spruce forests. Whitebark pine occurs in commercial volumes at lower elevations, mixed with hybrid spruce and lodgepole pine, and slopes at treeline. Alpine larch occupies a similar habitat in the southern half of the Section. Along the lower altitudinal boundary, limber pine appears on rocky soils, while in the vicinity of Jasper, Banff and Waterton there is some presence of interior Douglas-fir where contact is made with isolated patches of montane forest. The transition to plains grassland on the south and east side is marked by a fringe of trembling aspen groveland. The subalpine forest is a mountain counterpart of the boreal forest, and the primary member species of both show very close relationships. The Engelmann spruce of the former is matched by the white spruce of the latter, alpine fir by balsam fir, lodgepole pine by jack pine, and each pair of species apparently hybridizes where their ranges overlap. A marked difference in composition of the forest types of the two Regions is seen however in the relative unimportance in the Subalpine of trembling aspen, balsam poplar and white birch. Black spruce is also of limited importance compared to the role it plays in the boreal forests, and it is a rare tree south of the Red Deer River. The mountainous topography -- steep slopes and deep valleys -- has been developed on uplifted Mesozoic shales and sandstones with some local Cambrian limestones. The derived residual and glacial surface materials are variable in texture and composition, and under the influence of a wide range of local climatic conditions the soil development has also been variable. Most frequent are thin soils (lithic subgroups) over bedrock and shallow humo-ferric podzols; eutric and dystric brunisol profiles occur occasionally. |
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SA.2 |
Interior Subalpine: This is a much-fragmented forest, occupying to treeline the mountainous uplands which surround the Fraser and Nechako plateaus. In its northern part, beyond latitude 53o, it is the principal forest area of interior British Columbia. Characteristic is a forest of western white spruce, Engelmann spruce and their intermediate forms, associated with alpine fir which increases in abundance at higher altitudes and is dominant at treeline. Extensive stands of the pioneer lodgepole pine cover areas of past fires. In eastern British Columbia the lower boundary of the Interior Subalpine Section lies roughly between 3,600 and 4,000 feet above sea level, at which general elevation contact is made with the cedar-hemlock-fir stands of the Columbia Forest Region. Northward, the altitudinal range is lowered, and the spruce-pine forests are continuous from mountain slope to mountain slope across the intervening valleys. Here both black spruce and white spruce enter from the Boreal Forest Region to the north and east; in fact, north of 54o latitude the latter species is dominant and Engelmann spruce is apparently absent. Westward, on the lee side of the Coast Range, western hemlock with some western red cedar and amabilis fir, associates with white spruce, and scattered western white birch also appears. Along the upper altitudinal boundary the whitebark pine is usually represented on exposed rocky slopes, and in the southeastern parts the mountain hemlock and alpine larch have a local occurrence. The bedrock is largely of Palaeozoic sediments with Tertiary extrusions, although long-continued erosion has exposed the granitic cores of some of the mountains and produced surface materials of wide variability. Soil conditions are much as in the previous Section. |
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SA.3 |
Coastal Subalpine: Above the approximately 3,000 feet altitude on Vancouver Island and the west side of the mainland Coast Range, occupying a zone between the Douglas-fir-hemlock-cedar forets and the alpine tundra and snow fields, there is a forest with characteristics of both the Subalpine Forest and Coast Forest Regions. Mixed coniferous stands of amabilis fir, mountain hemlock and alpine fir are usual, these species decreasing in importance toward treeline in the order given. Yellow cypress is commercially important in some forest stands, though its exploitation is difficult due to the inaccessibility of most parts of the Section. No spruce species are present. A somewhat similar forest is found on the highest lands of the Queen Charlotte Islands, beginning at about the 2,000-foot contour, although true firs (Abies spp.) do not occur there. |
The Montane forest has developed in response to the prevailing dry climate of the central plateau of British Columbia and several southern mountain valleys adjacent to the Alberta boundary. The Region is a northern extension of the typical forest of much of the western mountain system in the United States and comes in contact with the Coast, Columbia, and subalpine forests. The characteristic tree is the interior or "blue" form of Douglas-fir. It is found throughout but more particularly in the central and southern parts. Lodgepole pine and trembling aspen are generally present, the latter being particularly well represented in the north-central portions. Engelmann spruce and alpine fir form the Subalpine Forest Region, together with western white birch, become important in the northern parts. White spruce is recognized as an important constituent of the exploitable forests. In the southern portion, ponderosa pine is abundant between the continental divide on the east and the Fraser Valley on the west. Extensive prairie communities of bunch-grasses and forbs are found in many of the river valleys.
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Map Symbol |
TEMVEG |
Description from Map Legends of Rowe (1974)a |
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M.1 |
Ponderosa Pine and Douglas-fir: This Section includes the southernmost part of the main montane forest on the Fraser plateau, and with it the narrow, steep-sided valley of the Kootenay River and a part of the upper Columbia River valley. Two different zones can be recognized: a lower savanna or "parkland" (south of latitude 51o) of open-grown ponderosa pine and occasional interior Douglas-fir, interspersed with bunch-grass prairie or weedy vegetation according to grazing history, and on steep slopes above 3,500 feet or so an upper or northern interior Douglas-fir forest, mixed or alternating with areas of trembling aspen and lodgepole pine. The pine forms a relatively permanent type over large areas in the western sectors of the Section because of the frequency of fires. Environmental features such as soil texture, aspect and exposure have a critical influence on the distribution of tree species because of the dry climate. For example, Engelmann spruce descends from the upper subalpine forests to mix with the Douglas-fir and lodgepole pine on cool, north-facing slopes, and in the south the ponderosa pine extends into the grassland on rocky or sandy soils and into the Douglas-fir zone on warm sunny slopes. White spruce occupies river flats and creek sides, and although it tends to maintain an altitudinal position below Engelmann spruce, the latter species frequently accompanies it on lowland alluvium. In some areas where the Columbia forest borders the montane, western larch and occasional western white pine are present on the drier sites, associated with the ponderosa and lodgepole pines. The plateau-land of eroded Palaeozoic and Mesozoic sediments and intrusions is moderately rugged in topography. The hills and low mountains have been strongly glaciated, and through the drift-filled lowlands the rivers flow in wide, terraced valleys where considerable later alluvial material has been laid down. Gray luvisol soil profile development is normal under the upland forests, while in the lower ponderosa pine zone, soils with more melanized profiles (dark brown, black or dark gray chernozems) are found. |
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M.2 |
Central Douglas-fir: This includes the northern half of the Fraser plateau, embracing the Fraser, Chilcotin, Bonaparte and middle North Thompson valleys. Ponderosa pine is absent, and the northern distribution limit of this species marks the southern boundary of the Section. The northern boundary is set physiographically by a transition to the more subdued relief of the Nechako plateau. West and east the boundary forests are subalpine and Columbia respectively. Interior Douglas-fir is the primary dominant of the somewhat drier lowland forests, though replaced over considerable areas by lodgepole pine after fire. Trembling aspen is well distributed, and at higher altitudes the intergrading Engelmann-white spruce complex and alpine fir enter from the subalpine forest. As in the former Section, bunch-grass prairie occupies the bottomlands and commonly extends up the lower mountain slopes, especially back from the Chilcotin, Fraser and Quesnel rivers. This northern part of the Fraser plateau has less relief than to the south; the valleys are broader and the hills are lower and more rounded. Many of the areas of slight relief mark ancient flows of Tertiary lavas. The effects of glaciation are seen in the form of upland tills, kame terraces, morainic hills and dammed lakes. Soils are chiefly gray luvisols, with transition to black chernozems in the valleys and to podzolic types on the slopes at higher altitudes. |
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M.3 |
Northern Aspen: The southern half of the Nechako plateau, bounded east and west by Sections of the Subalpine Forest Region, carries a forest in which trembling aspen plays a very important part due to the prevalence of past fires. Mixed with the predominant aspen is lodgepole pine, white spruce, some Engelmann spruce and scattered interior Douglas-fir. The stands are inclined to be open and irregular grassy areas are common in the valleys, particularly along the West Road River. There is evidence that, as in the B.17 Section of the prairie provinces, aspen is invading the grasslands. Black cottonwood is conspicuous on the alluvial flats of the lowlands. This is a rolling upland, with low mountains and rounded hills. Thick glacial deposits over the Mesozoic sediments and Tertiary lavas have contributed to the generally subdued relief. The soils developed under upland mixed forest cover are gray luvisol, though dark gray chernozem profiles are characteristic of the more open, park-like vegetation. |
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M.4 |
Montane Transition: The forests of the relatively low-lying land on the northern half of the Nechako plateau are transitional in composition between the montane and the subalpine forests. Relationship to the latter is most apparent, as the characteristic forest type consists of white spruce in the north, Engelmann spruce and the white-Engelmann hybrids elsewhere, and alpine fir. However, coast Douglas-fir is also scattered throughout (the interior variety appearing in the eastern parts), and its presence has led to the inclusion of this Section in the Montane Forest Section. The widely distributed spruce-fir forest has been decimated by fires, resulting in an expansion of associations of trembling aspen, western white birch and lodgepole pine. Along the rivers and lakes, black cottonwood is commonly found. Numerous grassy openings and parklands with groves of aspen occur, particularly in the western half of the Section. Under the present conditions of environment, Douglas-fir appears to be losing the position of prominence that it formerly had in the vegetation pattern, except perhaps in the drier, open forest types. On the eastern side of the Section, there is a gradation into the northern Columbia forest with the appearance of mixed stands of Engelmann spruce, western red cedar and western hemlock and of Engelmann spruce with Douglas-fir. Westward, there is a gradual merging with the northern coastal forests as hemlock and cedar again appear. The major part of the northern interior plateau is a rolling upland at about 2,500 feet altitude, and only a few hills and low mountains exceed 5,000 feet. The underlying bedrock is of rather flat-lying Palaeozoic and Mesozoic sediments, with some local Tertiary sediments and lavas. Large sections were flooded by post-glacial lakes, remnants of which still remain in the comparatively broad, flat valleys, and there has been a thick deposition of lacustrine deposits. Upper slopes and highlands are covered with glacial drift. The soils are gray luvisol or podzolic under coniferous stands, and dark gray chernozems or immature under the more open mixed and hardwood forests of the lowlands. |
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M.5 |
Douglas-fir and Lodgepole Pine: An association of the interior Douglas-fir and lodgepole pine is typical of most of the forests on the east slope of the Rocky Mountains in central Montana, and three small areas of similar forest condition appear northward in Canada: in the Porcupine Hills-Waterton Lakes District, on the Bow and Kananaskis rivers west of Calgary, and on the Athabasca River around Jasper. The forest stands of Douglas-fir and lodgepole pine are mostly confined to warm, dry slopes, while northern aspects, seepage spots and ravine bottoms are more commonly dominated by white spruce with some black spruce. At the higher altitudes, Engelmann spruce with alpine fir and some whitebark pine appear. Limber pine occurs on rock outcrops and stony soils at lower elevations and even at the forest-grassland transition, though here groves of trembling aspen with scattered white birch and white spruce more typically represent the general vegetation. The underlying rocks are altered or contorted Palaeozoic and Mesozoic sediments. The soils are largely colluvial in origin, and gray luvisol or podzolic in profile development. |
This is part of the Pacific Coast forest of North America. Essentially coniferous, it consists principally of western red cedar and western hemlock, with Sitka spruce abundant in the north, and with coast Douglas-fir in the south. Amabilis fir and yellow cypress occur widely, and together with mountain hemlock and alpine fir, are common at higher altitudes. Western white pine is found in the southern parts, and western yew is scattered throughout. Broadleaved trees, such as black cottonwood, red alder, and bigleaf maple, have limited distribution in this Region. Arbutus and Garry oak occur in Canada only on the southeast coast of Vancouver Island and the adjacent islands and mainland; the centres of population of these species lie to the southward in the United States.
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Map Symbol |
TEMVEG |
Description from Map Legends of Rowe (1974)a |
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C.1 |
Strait of Georgia: On the islands of the Strait of Georgia, on the adjacent east coast and on southeast Vancouver Island, and at scattered points along the mainland shores, two tree species not found elsewhere in Canada occur in association with the prevailing forests of coast Douglas-fir, namely arbutus and Garry oak. Of the two, the latter is almost entirely confined to the coastal fringe of the southeast part of Vancouver Island, although extensive stands are present on the mainland south of the International Boundary. Isolated patches, such as those reported some distance up the Fraser River, may be relicts from a climatically warmer period immediately after the last glaciation. The dominant of the well-drained sites is Douglas-fir, and the arbutus appears with it (or before it as a pioneer species) in the drier, open sites, particularly on the Gulf Islands. Garry oak tends to form pure groves, but is also found to a limited extent scattered in the above association, as is Rocky Mountain juniper. On lowland slopes, and alluvium subject to periodic flooding, western red cedar, grand fir, red alder and bigleaf maple appear, while shore pine occupies the wet acid peats. This pine species also persists in another extreme environmental niche: the crests of dry gravelly ridges. Western hemlock joins the Douglas-fir on a variety of sites, but it is best developed at higher altitudes in the neighboring Section (C.2). Sitka spruce is occasional on low ground. This area is related physiographically and climatically to the broad depression south of the International Boundary: the coastal trench between the Cascades and the Olympic mountains. Glacial and interglacial surficial materials as well as alluvial, deltaic and marine deposits overlie Cretaceous sediments on the Island and granitic intrusions on the mainland coast. Influenced by the summer-dry maritime climate, a wide variety of soils has developed under different cover types on diverse sites. In well-drained positions, profiles of the dystric and sombric brunisols and black chernozem are found, while peaty phase gleysols and immature alluvial soils are usual where drainage is imperfect to poor. |
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C.2 |
Southern Pacific Coast: The Section includes the southern part of the Coast forest, extending over most of Vancouver Island and embracing also the protected parts of the indented coastal zone on the adjacent mainland north to Kemano. Environmental conditions are optimal for growth of the large western conifers -- coast Douglas-fir, western hemlock, western red cedar -- and the forest productivity of the land is the highest in Canada. Here also is the main area of abundance in western British Columbia of western white pine and, at low elevations on the mainland, of grand fir. The upper altitudinal boundary of the Section, on the mountain slopes of the mainland and in the Island interior, is set by the transition to the Coastal Subalpine Section (SA.3) with its distinctive tree composition. The northern and western boundaries are marked by the decreased importance of Douglas-fir in the general forest vegetation, correlated perhaps with a climatic trend toward increased precipitation and increased exposure to Pacific winds. North of latitude 50o the Section boundary is close to the geographical range of Douglas-fir. The forest cover is mostly of even-aged Douglas-fir, western hemlock, western red cedar and, in the south, scattered western white pine. In sheltered valleys and protected moist slopes, uneven-aged stands of western red cedar and hemlock, or of cedar, hemlock and amabilis fir are sometimes found, suggesting that the role of Douglas-fir is primarily that of a pioneer after fire. However, there is some evidence that in rain-shadow areas, and on drier sites in general, Douglas-fir forms rather stable forest types. Western red cedar is the characteristic tree of sites with abundant seepage water, and on alluvial soils it is frequently accompanied by black cottonwood, Sitka spruce, grand fir, red alder and bigleaf maple. The latter two deciduous species often invade logged areas vigorously, to the detriment of coniferous regeneration. The tolerant western hemlock achieves its greatest prominence in old forest stands on cool, moist sites, and with amabilis fir it dominates much of the forest above approximately the 1,600-foot contour. Other species of limited importance are shore pine, western white birch, cascara and, at the higher elevations, yellow cypress. Underlying rocks are mainly late granitic intrusions on the mainland, and Palaeozoic and Mesozoic volcanics on Vancouver Island. The soil material is derived from surface tills of the last glaciation, and the soil types belong to the dystric brunisol, humo-ferric podzol and regosol groups. |
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C.3 |
Northern Pacific Coast: This covers the portion of the Coast forest which occupies the exposed western side of Vancouver Island, the Islands (excepting the Queen Charlotte group) and adjacent mainland bordering on Queen Charlotte Sound and Hecate Strait, and many of the glacially enlarged valleys which extend far inland in the area surrounding the Alaska panhandle. Contact on Vancouver Island is with the preceding Section (C.2) but from here northward to the Portland Canal the interior boundary is set altitudinally by the Coastal Subalpine Section (SA.3). Small patches of the Section meet boreal forest on the Stikine and Taku rivers and, in extreme northwestern British Columbia, on the Tatshenshini and Alsek rivers. The principal associates on well-drained sites are western hemlock and amabilis fir, the place of the latter species being taken by western red cedar where the ground water table is high. Sitka spruce, alone or mixed with western hemlock, is characteristic of alluvial soils, and on such sites there may also be yellow cypress, red ald |