Alberta's Boreal Forest Natural Region
Updated December 15, 2006
Short summers, long,
cold winters and vast
and coniferous forests
characterize the Boreal
Forest Natural Region.
This is Alberta’s largest
Natural Region; it
occupies over half the
Province and includes
eight Natural Subregions
The Boreal Forest Natural Region includes the
Dry Mixedwood, Central Mixedwood, Lower
Boreal Highlands, Upper Boreal Highlands,
Athabasca Plain, Peace–Athabasca Delta,
Northern Mixedwood, and Boreal Subarctic
Natural Subregions. It occupies most of
northern Alberta, and extends south almost to
Elevations range from about 150 m in the Northern Mixedwood Natural Subregion near the Alberta–Northwest Territories border to over 1100 m in the Upper Boreal Highlands Natural Subregion near the Alberta–British Columbia border. Level to undulating till and lacustrine plains interspersed with extensive wetlands are the dominant landforms; hummocky landscapes, high-elevation plateaus and extensive dune fields also occur.
This Natural Region is vegetated by deciduous, mixedwood and coniferous forests. Cultivation is limited to those areas that have a sufficiently long growing season. Aspen and balsam poplar are the most common deciduous species; white spruce, black spruce and jack pine are the dominant conifers. Wetlands are dominantly black spruce, shrub or sedge fens. The dominant soils are Luvisols on uplands and Mesisols in wetlands.
The boundaries between some boreal Natural Subregions are relatively well defined, such as those defined by elevation criteria or slope breaks (e.g., the boundary between the Lower Boreal Highlands Natural Subregion and the adjacent Boreal Subarctic or Upper Boreal Highlands Natural Subregions). The boundaries for other boreal Natural Subregions are more gradual (e.g., the boundary between the Dry Mixedwood and Central Mixedwood Natural Subregions), and differences in vegetation and soils may not be evident for several kilometers on either side of the mapped boundary.
The following links provides basic information on the key characteristics at the subregion level.
- Dry Mixedwood Natural Subregion
Undulating plains, aspen-dominated forests and fens define the Dry Mixedwood Natural Subregion, the warmest boreal Natural Subregion.
- Warmer summers and milder winters than most other Subregions in the Boreal Natural Region.
- Aspen stands with scattered white spruce interspersed with fens; cultivated areas on suitable soils throughout.
- Two climatically distinct areas within this Natural Subregion (Peace River and southern).
- Gray and Dark Gray Luvisols on uplands; Gleysols and Organic soils in wetlands.
The Dry Mixedwood Natural Subregion is the second largest Natural Subregion in Alberta and is mapped as three separate units.
- The largest, most northerly unit parallels the Peace River in northwestern Alberta from Grande Prairie to Fort Vermilion.
- The second unit lies to the south and occupies a crescent-shaped area in central Alberta between the Central Parkland and the Central Mixedwood Natural Subregions. The Lower Foothills Natural. Subregion borders the Dry Mixedwood Natural Subregion in the extreme south.
- The third and smallest unit is associated with morainal uplands in the Cooking Lake area immediately east of Edmonton.
In the following discussion, the second and third units are considered together as a single southern unit. Elevations range from 200 m along the Peace River in the extreme northeast part of the Natural Subregion to 1225 m west of Sundre and adjacent to the Lower Foothills Natural Subregion.
Level to gently undulating glacial till or lacustrine plains are the dominant terrain type. Hummocky uplands are significant in the two southern mapped units. Gray Luvisols are the dominant soils on uplands; Gleysols and Organic soils are dominant in wetlands.
Aspen forests with mixed understories of rose, low-bush cranberry, beaked hazelnut and Canada buffaloberry are typical on uplands. Treed, shrubby or sedge-dominated fens occupy about 15 percent of the Natural Subregion. Jack pine stands occur on dry, well to rapidly drained glaciofluvial and eolian precipitation are higher in the southern part of this Subregion than in the Peace River area. Growing degree-days are highest in the Peace River area and west and north of Edmonton, and lowest east of Edmonton and along the foothills to the west.
The prevalence of early to mid-seral aspen forests in the Dry Mixedwood Natural Subregion, and the relative scarcity of white spruce compared to the adjacent Central Mixedwood Natural Subregion, might be in part due to a higher incidence of lightningcaused fires in the Dry Mixedwood.
- Central Mixedwood Natural Subregion
Vast expanses of upland forests and wetlands on level to gently undulating plains, short, warm summers and long, cold winters define the Central Mixedwood Natural Subregion. This is the largest Natural Subregion in Alberta.
- A mosaic of aspen, mixedwood and white spruce forests on uplands, with extensive areas of mainly treed fens in central areas and jack pine stands on coarser materials to the east.
- On average, slightly cooler and moister than the Dry Mixedwood Natural Subregion, but its extent results in north-to-south variability.
- Gray Luvisolic soils on medium to fine textured upland sites, with Brunisols on sands and Organic soils in poorly drained lowlands.
The Central Mixedwood Natural Subregion occupies 25 percent of Alberta, stretching south from the Caribou Mountains and Cameron Hills to just north of Red Deer, and spanning the province from the British Columbia to Saskatchewan borders. It shares boundaries with most of the other boreal Natural Subregions, as well as with the Lower Foothills Natural Subregion. Total area: 167,856 km2 (44% of Boreal Forest Natural Region). Average elevation: 525 m (range 200-1050 m.
Elevations range from 200 m along the Peace River in the northeast to 1050 m in the extreme south. Gently undulating plains with some hummocky upland inclusions are the primary landforms. Parent materials are medium textured tills, fine textured lacustrine deposits, coarse textured fluvial and eolian deposits, and organic deposits.
On upland areas, a mix of aspen-dominated deciduous stands, aspen-white spruce stands, and white spruce-dominated stands are typical of till and lacustrine areas, with jack pine forests on coarse materials. Wetlands are often extensive and are dominantly black spruce fens and bogs. Luvisolic soils are typical of uplands and Organic soils are dominant in wet, poorly drained areas.
- Lower Boreal Highlands Natural Subregion
Diverse mixedwood forests on moist lower slopes of northern hill systems and extensive wetlands at slope bases and on adjacent lowlands are typical of the Lower Boreal Highlands Natural Subregion.
- Diverse young forests of aspen, balsam poplar, black and white spruce, white birch and lodgepole pine-jack pine hybrids on slopes with treed, shrubby or graminoid fens in depressions, seepage zones or level areas.
- Slightly colder winters and warmer summers than the higher-elevation Upper Boreal Highlands Natural Subregion. Moister and cooler than the adjacent Central Mixedwood and Dry Mixedwood Natural Subregions.
- Gray Luvisols (often gleyed); wetlands are Organic soils and Gleysols.
The Lower Boreal Highlands Natural Subregion is the third largest Natural Subregion in Alberta and is the boreal analogue of the Lower Foothills Natural Subregion. It includes the lower slopes of the Cameron, Buffalo Head, Naylor and Clear Hills, Caribou and Birch Mountains, part of the Chinchaga Plain, and all the Stony Mountain and Peerless Uplands. It surrounds the higher elevation Upper Boreal Highlands and Boreal Subarctic Natural Subregions, and is bordered at lower elevations by the Central Mixedwood and Dry Mixedwood Natural Subregions. Elevations range between 400 m and 800 m in the Cameron Hills and Caribou Mountains, and between 700 m and 1000 m in the southern Clear Hills. This reflects a south-to-north decline of approximately 0.55 meters per kilometer for the upper boundary and a 0.82 m per kilometer decline for the lower boundary.
Medium textured glacial till deposits occur on gentle to strong lower slopes and hummocky to undulating uplands, with lacustrine and organic deposits in the lowlands. Forests are more diverse than those found in adjacent Natural Subregions. In addition to aspen and white spruce forests on uplands, balsam poplar and white birch forests often occur in seepage areas and lodgepole pine-jack pine hybrids are common in pure and mixed stands with black spruce and deciduous species. Luvisols and gleyed subgroups occur on well to imperfectly drained upland sites, Brunisols on coarse textured soils, and Organic soils and Gleysols on poorly drained areas.
- Upper Boreal Highlands Natural Subregion
Coniferous forests on the upper slopes and undulating plateaus of northern hill systems, short, cool and showery summers and cold winters together define the Upper Boreal Highlands Natural Subregion.
- Predominantly coniferous forests (lodgepole pine-jack pine hybrids, white and black spruce) with locally extensive wetlands in low-lying portions of the plateaus.
- Moister with cooler summers than the adjacent Lower Boreal Highlands Natural Subregion.
- Orthic and Brunisolic Gray Luvisols (often gleyed); wetlands are Organic soils and Gleysols.
The Upper Boreal Highlands Natural Subregion includes the upper slopes and plateaus of the Buffalo Head, Naylor and Clear Hills, and the Birch Mountains. It is entirely surrounded by the Lower Boreal Highlands Natural Subregion. Elevations range from 825 m in the eastern Birch Mountains to 1100 m in the western Clear Hills. Medium textured glacial till deposits occur on slopes, with colluvial and residual materials on steep slopes and organic deposits in depressions on the plateaus. Forests are mainly coniferous, and both lodgepole pine and lodgepole pine-jack pine hybrids occur together with black spruce. Luvisols and gleyed subgroups occur on well to imperfectly drained upland sites, and Organic soils, Cryosols and Gleysols occur on poorly drained areas.
- Athabasca Plain Natural Subregion
Dry, sandy plains, dune fields and gravel-cored hill systems, open shrub or jack pine communities, warm summers and long, very cold winters together define the Athabasca Plain Natural Subregion.
- Coarse textured gravels and sands throughout the entire area.
- Relatively warm summers and long growing seasons compared to other boreal Natural Subregions.
- General Jack pine forests and low shrublands with sedge fens in low areas and some unvegetated areas (active dunes). Soils are Brunisols, Regosols or Mesisols.
The Athabasca Plain Natural Subregion occurs south of Lake Athabasca along the Alberta- Saskatchewan border. Adjacent Natural Subregions are the Kazan Upland and Peace- Athabasca Delta to the north and northwest, and the Central Mixedwood to the east. Elevations range from 200 m near Lake Athabasca to about 650 m in the southeastern Firebag Hills.
Strongly hummocky and rolling sandy and gravelly uplands occur in the eastern and southern portions. Level to undulating sandy fluvial and eolian plains with some prominent dune fields occur to the east and north. Dune areas have unique communities that stabilize the dune surfaces, but areas of bare sand do exist. Elsewhere, dry jack pine stands with sparse understories are the dominant upland vegetation, with sedge meadows in low-lying terrain. Soils are Brunisols on the uplands, Regosols on the active dunes, and Mesisols in wetlands. The Athabasca Plain Subregion has a number of significant invertebrate species that are out of range, rare, or are the first records for this part of Alberta.
- Peace-Athabasca Delta Natural Subregion
The Peace-Athabasca Delta Natural Subregion is a wet expanse of lakes, rivers, creeks, marshes, sedge meadows, shrublands and riverine forests; summers are warm and winters are long and very cold.
- One of the world's largest freshwater deltas.
- Warm summers and long growing seasons, very cold winters.
- Many large and small lakes, extensive sedge meadows and willow-dominated shrublands underlain by wet mineral soils; Organic soils are uncommon.
The Peace-Athabasca Delta Natural Subregion lies south and west of Lake Athabasca. It is bordered on the west by the Central Mixedwood Natural Subregion, on the north by the Kazan Uplands Natural Subregion, and on the east and south by the Athabasca Plain Natural Subregion. It is the lowest elevation Natural Subregion in the province and is nearly flat. Elevations range from 200 m along the Slave River to about 250 m in small elevated granite exposures within the Delta. Water is the dominant feature. Most of the vegetation throughout the Natural Subregion is a mixture of submerged and emergent aquatic communities, sedge fens and willow shrublands. Deciduous and coniferous forests occur on fluvial terraces or levees along streams and rivers, and dry jack pine forests and lichen communities occur on granite exposure. Soils are Regosols and Gleysols. Only very minor parts of the area in the Peace- Athabasca Delta Natural Subregion are occupied by deep, medium textured, well drained soils and their associated vegetation. The site characteristic of most of the area in this Natural Subregion is wet, nutrient rich, and vegetated by sedges, other grass-like plants, herbs and shrubs.
- Northern Mixedwood Natural Subregion
Far northern lowelevation black spruce bogs and fens, frozen Organic soils, short, warm and dry summers and long, very cold winters define the Northern Mixedwood Natural Subregion.
- Wetlands with Organic soils are the dominant landscape feature, and permafrost occurs over significant areas.
- Black spruce is common both on uplands and in wetlands; deciduous and mixedwood stands are uncommon, restricted to river terraces, valleys, and elevated well drained areas.
The Northern Mixedwood Natural Subregion occurs in the far north, occupying the lowlands adjacent to the Alberta-Northwest Territories border and a smaller, higher elevation area in the northwestern Cameron Hills. Its main border is with the Central Mixedwood Natural Subregion, but it also borders the Kazan Upland Natural Subregion to the east and the Lower Boreal Highland Natural Subregion to the west and around the northern base of the Caribou Mountains.
Elevations range from 150 m along the Hay River in the northwest to 650 m in the Cameron Hills. Gently undulating plains are the dominant topographic form. There are a few hummocky inclusions and areas of karst topography in the eastern portion. Organic deposits cover extensive areas in the western and central plains, with fine textured glaciolacustrine materials at lower elevations and till deposits in the Cameron Hills portion. Fine textured glaciolacustrine and sandy eolian materials are common in the eastern third where organic deposits are less extensive.
On upland areas, white and black spruce stands are typical, with mixedwood aspen-white spruce-black spruce stands on better drained soils along rivers and on local well-drained elevated areas. Much of the Natural Subregion is wetland, and is vegetated by open, stunted black spruce stands, often with permanently frozen Organic soils. The conventional reference site concept of deep, medium textured, well drained soils and their associated vegetation does not adequately fit most of the Northern Mixedwood Natural Subregion, where typical sites are wet and poorly drained, and soils are often permanently frozen.
- Boreal Subarctic Natural Subregion
Elevated plateaus in far northern Alberta, open black spruce bogs with frozen Organic soils, short, cool summers and long, very cold winters are unique characteristics of the Boreal Subarctic Natural Subregion. Many subarctic bird, insect and plant species that are common in the Northwest Territories occur in Alberta only in this Natural Subregion.
- Higher elevations in the Caribou Mountains and Cameron Hills, with climate conditions that restrict plant growth and produce extensive areas of frozen Organic soils.
- Open black spruce stands, peatland complexes and permafrost terrain.
The Boreal Subarctic Natural Subregion occurs on high-elevation plateaus in the Cameron Hills and Caribou Mountains. It is completely surrounded by the Lower Boreal Highlands Natural Subregion except for a very small area in the Cameron Hills where the Northern Mixedwood Natural Region lies adjacent. Elevations range from 575 m to over 1000 m in the western Caribou Mountains.
Landscapes are primarily undulating and rolling plateaus and highlands, with extensive low-lying, poorly drained areas. Most of the area is covered by organic deposits; fine textured glacial till deposits are also common. Fires are frequent and open, stunted black spruce stands with shrub, moss and lichen understories occur across large areas, underlain by frozen, poorly drained organic materials. Moderately well drained upland areas occupy minor areas of the Natural Subregion, and a variety of upland forests may occur, dominated by pure or mixed aspen, white spruce, black spruce, Alaska birch and lodgepole pine.
The conventional reference site concept of deep, medium textured, well drained soils and their associated vegetation does not adequately fit most of the Boreal Subarctic Natural Subregion, where typical sites are wet, poorly drained and very cold.
The new Natural Regions and Subregions of Alberta Report (5.2 MB) is now available.
View the Errata Report(23 KB) for the printed and digital versions of the above report, prior to May 15 2006.