OVERVIEW OF CANADA’S MAJOR FOREST ECOZONES

Canada is a forest nation. Its forests cover 41% of its land mass and represent 10% of the world’s forests and approximately 30% of the boreal forest. Forests play an important role in the economic, social, and spiritual well-being of Canadians.

Canada is in a unique position because the majority of its forests (93%) are crown-owned. The remaining 7% are owned by about 425 000 private landowners. Most of Canada’s stocked forest is managed under provincial or territorial jurisdiction.

Canada is the largest exporter of forest products worldwide. The economic health of the forest sector is important to the continued prosperity of the nation, generating 30% of all manufacturing investment.

Forests provide wilderness areas for the cultural, spiritual, and recreational benefit of all Canadians and for visitors to Canada and support an important and growing recreation and tourism industry.

Canada is host to a diversity of forest ecosystems and tree species. The 1996 National Ecological Framework (Terrestrial Ecozones of Canada tear-out map at back) divides the country into 15 terrestrial ecozones, 53 ecoprovinces, 194 ecoregions, and more than 1000 ecodistricts (Ecological Stratification Working Group 1996, Marshall and Schut 1999) delineated on the basis of the interactions of geological, landscape, soil, vegetation, climate, wildlife, water, and human factors. The majority of Canada’s forests lie within the eight ecozones discussed below (Wiken 1986, Wood and Addison 1997, Urquizo et al. 2000).

The Taiga Plains ecozone is bordered on the west by the cordillera mountain ranges, to the east by Great Bear Lake and Great Slave Lake, to the north by the Mackenzie River delta, and to the south by the closed forests of the Boreal Plains ecozone. Short, cool summers and long, cold winters result from the influence of arctic air for most of the year.

Taiga Plains

The ecozone is about 57% forest but has relatively little standing timber volume per hectare. Taiga is a Russian word that means literally “the land of little sticks” and refers to the northern edge of the boreal coniferous forest. This ecozone is a transition between mixed forest–tundra and dense coniferous forest. The predominant tree is black spruce, which generally occurs as an open, slow-growing species in the ecozone. Along the nutrient-rich alluvial flats of the larger rivers, white spruce and balsam poplar grow to sizes comparable with the largest in the boreal forest. The Mackenzie River, Canada’s largest river, dominates the ecozone, and the Mackenzie Valley forms one of North America’s most traveled migratory corridors for waterfowl breeding along the Arctic coast.

The population of 32 929 (density 0.05, measured in persons/km2) is approximately 60% Aboriginal. Mining, oil and gas exploration, and some forestry and tourism are the main activities in the ecozone.

The Boreal Cordillera ecozone, covering sections of northern British Columbia and the southern Yukon, has a Pacific Maritime influence that moderates temperatures over most of its area. The climate is marked by long, cold winters and short, warm summers.

Boreal Cordillera

The ecozone is 51% forest. Vegetative cover ranges from closed- to open-canopy forest. Tree species include white and black spruces, alpine fir, lodgepole pine, trembling aspen, balsam poplar, and white birch. The tree line ranges from 1500 m in the southeast to about 1200 m in the northwest, where the stands are generally open, and there are almost no lodgepole pine or alpine fir. Shrub birch–willow communities are common in the subalpine forest and extend into the alpine tundra above the tree line. Permanent ice and snow fields occur in the mountains along the western side of the ecozone.

This ecozone is sparsely populated, with the majority of the population of approximately 28 038 (density 0.06) residing in the larger communities of Whitehorse and Dawson City. The major economic activity is mining followed by forestry, tourism, and hydroelectric development. Some agriculture is associated with the large watersheds.

The Boreal Plains, extending from Peace River, British Columbia, in the northwest to the southeastern corner of Manitoba are part of the boreal forest. Unlike the neighboring Boreal Shield, the Boreal Plains ecozone has few bedrock outcrops, fewer lakes, a higher percentage of nonforest land, and some private lands.

Cold winters and moderately warm summers are characteristic of the climate which is strongly influenced by continental climatic conditions. Jack and lodgepole pines, white and black spruces, and tamarack are the main coniferous species, and mixed stands of aspen and white spruce occur on nutrient-rich sites. A two-stage silvicultural system, involving harvest of the aspen canopy while protecting the valuable white spruce understory, is followed in these mixedwood stands.

Boreal Plains

The population of the ecozone is 731 858 (density 1.0). Major land uses in the Boreal Plains include agriculture, forestry, oil and gas exploration, mining, hunting and trapping, outdoor recreation, and tourism.

The Boreal Shield ecozone stretches from the eastern tip of Newfoundland to the northeastern corner of Alberta. At 195 million ha, it is the largest ecozone in Canada, encompassing almost 20% of Canada’s land mass, and accounts for 22% of the country’s freshwater surface area.

The headwaters of numerous large drainage basin systems such as the Nelson and Churchill Rivers in Manitoba, the St. Lawrence River in Ontario, and the Eastmain, Rupert, Nottaway, and Broadback Rivers in Quebec are found in this ecozone. The abundance of water attracts hundreds of thousands of migratory birds and provides important habitats for fish and other aquatic organisms.

The ecozone has a strongly continental climate characterized by long, cold winters and short, warm summers except in the coastal margins where it is moderated by maritime conditions. Vegetation in the Boreal Shield is the result of cool temperatures, a short growing season, frequent forest fires, and acidic soils. The ecozone is more than 74% forest and much of it remains in wilderness condition. Closed stands of conifers, largely white and black spruce, balsam fir, and tamarack, are characteristic. Toward the south, there is a wider distribution of broadleaf trees such as white birch, trembling aspen, and balsam poplar and needle-leaved trees such as white, red, and jack pine. Tree growth and timber volume are lower than in most of the other forest ecozones in Canada.

Boreal Shield

Fire suppression and harvesting have resulted in an increase in the balsam fir content of stands, usually at the expense of white spruce. In the eastern portion of the ecozone, balsam fir is often the dominant species, but the challenge is to protect it from spruce budworm (a native pest that can be destructive during major outbreaks) long enough for the trees to reach rotation age or a size at which they can be harvested. In the central and western portions of the ecozone, balsam fir is an understory component of boreal mixedwood stands but is not as important a commercial species as in the east. On lowland sites in the Boreal Shield, black spruce occurs in nearly pure stands. Natural regeneration is emphasized in the ecozone, partly to conserve genetic and structural diversity within stands. Fire suppression and harvesting practices throughout the ecozone have also resulted in a shift from conifers to hardwoods, particularly in the boreal mixedwoods and the red pine and white pine stands in the southern part of the ecozone.

With a total population of 3 060 830 (density 1.6), the Boreal Shield is home to roughly 10.2% of Canada’s population. Almost 60% of the population lives in urban centers, the largest of which is St. John’s, Newfoundland. Many towns have developed around the rich natural resource base. According to estimates published in 2000, mining and forestry each account for 5.4% of the total labor force with fisheries and agriculture contributing 2.5% and 2.2%, respectively (CCFM 2000). Other commercial activities include hydro power, water-oriented recreation, tourism, and commercial and subsistence hunting, trapping, and fishing.

The Pacific Maritime ecozone extends in a thin zone along the Pacific coast. This ecozone has some of the warmest and wettest climatic conditions in Canada. Relative to the rest of the country, there is little variation in mean monthly temperatures.

The ecozone is divided almost evenly between forest and nonforest land. Mountainous topography dominates the landscape, with numerous fiords and glacial valleys, bordered by coastal plains along the Pacific margin. The ecozone is characterized by large trees, steep slopes, and old forests with long intervals between disturbances such as fire or windstorms.

Pacific Maritime

Forestry is the principal activity. Forest productivity and the cost of harvesting wood are the highest in the country. The lowlands of the Fraser Valley and the southeastern tip of Vancouver Island have an expanse of highly productive agricultural soils and urban lands. Fishing, transportation, and tourism are other economic activities. The total population of 3 028 745 (density 14.5) is concentrated in Vancouver and the lower mainland and in Victoria.

The Montane Cordillera ecozone, nestled between the Pacific Maritime, Boreal Plains, and the Boreal Cordillera ecozones, is the most complex of all the ecozones, with an exceptional diversity of topography and climate. Several mountain ranges run north to south and there are a number of interior plains. It is also home to Canada’s only true desert. Depending on elevation and exposure, vegetation ranges from alpine tundra to dense conifer forest that is almost coastal in appearance, to high elevation subalpine fir and Englemann spruce, to dry sagebrush and grasslands. The ecozone has more than 11 000 lakes and seven major river systems including the headwaters of the Fraser and Columbia Rivers.

Montane Cordillera

The Montane Cordillera is a fire-dominated ecosystem. Approximately 73% of the area is forest. Fire suppression has resulted in the accumulation of too much older age class forest that is becoming more and more prone to catastrophic wildfire. With aggressive fire suppression, insects such as bark beetles are able to have a major impact on the forest. After the Pacific Maritime, this ecozone has the highest volume of standing timber.

Forestry is an important economic activity, particularly in the northern interior sections. Mining, gas and oil production, and tourism are also significant economic activities in the ecozone. A series of national and provincial parks has been established in the Rocky and Columbia Mountains for recreational use or to preserve wildlife habitat. Although this ecozone is much less urbanized than the Pacific Maritime ecozone, more than half of its 927 348 (density 1.9) inhabitants live in cities and towns such as Prince George, Kelowna, Kamloops, Penticton, and Vernon.

The Mixedwood Plains ecozone covers the Great Lakes–St. Lawrence River valley. The ecozone is the northernmost extension of the deciduous forest biome that extends throughout much of the eastern United States. The climate is marked by hot, humid summers and cool winters. Geographic location, waterways, and a combination of gentle topography, fertile soils, a warm growing season, and abundant rainfall have made this the most densely populated and intensely used area in Canada.

Mixedwoods Plains

Once heavily forested, the Mixedwood Plains supported a greater diversity of trees and plants than any other part of Canada. It now has just over 20% forest cover, ranging from the mixed deciduous–coniferous stands in the northern portions to the highly diverse deciduous stands of the Carolinian forest in the southwest near Windsor, Ontario. Most of the deciduous forest has been cleared away for farms, orchards, highways, and cities. Over the course of two centuries of settlement and development, a characteristic fragmented landscape mosaic of agriculture, urban development, and remnant natural areas has emerged. Pressures on the remaining woodlands are expected to increase as the human population within the ecozone continues to grow.

Spanning the shorelines of three of the Great Lakes, this ecozone includes important aquatic ecosystems, industrial complexes, and recreation areas. Manufacturing and services are the prominent economic activities. Approximately 51% of Canada’s population, or 15 435 173 people (density 93.6), reside in the ecozone. Almost 85% of the residents live in urban centers stretching along the Windsor–Québec corridor, where two of Canada’s largest cities, Montréal and Toronto, are situated.

The Atlantic Maritime ecozone covers all of Nova Scotia, New Brunswick, Prince Edward Island, and part of Quebec. The Atlantic Ocean creates a cool, moist maritime climate. The ecozone is heavily forested with mixed stands of conifers and deciduous species. There is a long history of European settlement, with most of the native forest being burned or harvested at least once in the past two centuries. This ecozone has the highest percentage of private woodlots in Canada.

Atlantic Maritime

Natural regeneration following harvesting is common in the Atlantic Maritime ecozone. Specialized fill planting or diversity planting may be used to complement natural regeneration where necessary. A two-pass harvesting system has been introduced whereby balsam fir and hardwoods are removed during the first pass. The spruce component, retained for diversity and regeneration, is harvested about 20 years later.

Agriculture, forestry, and mining are the major land-based activities, while in coastal communities, fishing has traditionally been the most important source of income. Tourism also contributes to the economy of the ecozone. The majority of the population of 2 546 513 (density 12.2) is found in coastal lowland communities.

REFERENCES


(CCFM) Canadian Council of Forest Ministers. 2000.
Criteria and indicators of sustainable forest management in Canada. National status 2000. Natural Resources Canada, Canadian Forest Service, Ottawa, ON. 122 p.
Ecological Stratification Working Group. 1996.
A national ecological framework for Canada. Agriculture and Agri-Food Canada, Research Centre for Land and Biological Resources Research, and Environment Canada, State of the Environment Directorate, Ecozone Analysis Branch, Ottawa, ON/Hull, QC. 125 p. + map.
Marshall, I.B.; Schut, P.H. 1999.
A national ecological framework for Canada. Environment Canada, Ecosystems Science Directorate, and Agriculture and Agri-Food Canada, Research Branch, Ottawa, ON.
Urquizo, N.; Bastedo, J.; Brydges, T.; Shear, H., editors. 2000.
Ecological assessment of the Boreal Shield ecozone. Environment Canada, Environmental Conservation Service, Indicators and Assessment Office. Ottawa, ON. 71 p.
Wiken, E.B., compiler. 1986.
Terrestrial ecozones of Canada. Ecological land classification series, No.19. Environment Canada, ECS-1AO. Hull, QC. 26 p. + map.
Wood, J.; Addison, P., compilers. 1997.
Canada’s forests. Natural Resources Canada, Canadian Forest Service, Effects of Forestry Practices Network. Victoria, BC. http://www.pfc.forestry.ca/canforest/ index_e.html. Accessed March 2005.