What is the boreal forest?

Draped like a green scarf across the shoulders of North America, the boreal or "northern" forest is Canada's largest biome or environmental community. It occupies 35% of the total Canadian land area and 77% of Canada's total forest land, stretching between northern tundra and southern grassland and mixed hardwood trees. The boreal forest's animals, plants and products affect each Canadian every day, from paper products, to the jack pine railway ties, through to the air we breathe. This northern forest, named after Boreas, the Greek god of the North Wind, is an inevitable and unavoidable part of who we are.

Starting in the Yukon Territory, the boreal forest forms a band almost 1000 kilometres wide sweeping southeast to Newfoundland and Labrador. To its north is the treeline and beyond that the tundra of the arctic. To its south, the boreal forest is bordered by the subalpine and montane forests of British Columbia, the grasslands of the Prairie Provinces, and the Great Lakes - St. Lawrence forests of Ontario and Quebec.

The boreal forest is an integral part of our economy, history, culture and natural environment. It gives birth to new life through its diverse ecosystems and helps to sustain our lives through the renewal of the air above and soil below. This vast body of land provides the lakes, streams and rivers that act as the veins and arteries of so much of our country. It is also an important source of forest products, and, thereby, a significant part of the economic base of Canada.

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Figure 1. Forest Regions of Canada

The Boreal Forest Region is one of the nine forest regions of Canada. These regions are differentiated from each other based on differences in terrain, soil and climate. The boreal forest, shown in green, is by far the largest occupying 77 percent of Canada's forested land.

The boreal forest is characterized by the predominance of coniferous trees. Fossil records show that their first occurrence was during the Miocene Epoch, from 12 to 15 million years ago. From this time forward the boreal forest's adaptation to the immense forces of fire, glacial ice, insect infestation and disease have produced the forest for which we now have stewardship. These natural disturbances have been and continue to be necessary for the maintenance of the forest's ecological balance. Human activities, such as tree harvesting, mining, manufacturing, resource development and recreational use are causing stress and changes to this land. Their cumulative and long-term effects will cause far-reaching and potentially disastrous changes to the forest.

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Figure 2. Vegetation Zones in the Boreal Forest

The vegetation zones shown on this map are shown using a composite and interpreted satellite image. Data from the summers of 1988 to 1991 were used to produce this cloud free composite of the entire country.

A Global Ecosystem

Canada's boreal forest is part of a great northern circumpolar band of mostly coniferous trees extending across the subarctic latitudes of Russia, Scandinavia and North America. Globally, the boreal forest comprises almost 25% of the world's closed canopy forest as well as vast expanses of open transitional forest.

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Figure 3. Northern Circumpolar Map of the Boreal Forest

The boreal forest plays a significant role in the earth's environmental balance. Besides being a producer of oxygen, the boreal forest absorbs and stores carbon dioxide and so plays a critical role in mitigating global warming. Canadians cannot forget they are custodian to one third of this essential global resource.

The distribution of the boreal forest is closely related to climate. The climate of the boreal forest is characterised by long, extremely cold, dry winters and short, cool, moist summers.

The Boreal Mosaic

The boreal forest ecosystem is an interconnected web of life. It is a dynamic system of living organisms, plants, animals, insects and micro-organisms, interacting with the physical environment of soil, water and air.

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The boreal forest

Trees are the most visible and main structural elements of the forest ecosystem. The boreal forest is dominated by a small number of needle-leaved coniferous tree species of spruce, fir, larch (tamarack) and pine.

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Coniferous trees of the boreal forest

There are also several cold-hardy broadleaved tree and shrub species in particular, birch, poplar, willow, alder and mountain ash. Even though all these species and the associated shrubs, herbs, mosses, lichens and fungi range widely through the boreal forest, there is, nevertheless, a considerable regional diversity in boreal forest makeup from south to north and from east to west.

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Broadleaf trees of the boreal forest

Natural disturbances contribute to the landscape diversity of the boreal forest. Fire, insect infestation (such as the spruce budworm), disease and windthrow take place at different times and places across the forest. The result of this is a patchwork or "mosaic" of many different sized, even-aged groups of trees at different stages of growth.

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Insects of the boreal forest

In spite of the cold temperatures, a short growing season and nutrient-poor soils, the vast extent of the boreal forest results in a significant standing biomass. This accounts for its value as a forest resource as well as its influential role on global climate.

The boreal forest is divided into two great transcontinental belts of approximately equal size: the subarctic open lichen woodland and the closed crown forest. This major horizontal sectioning of the two areas reflects the steady dropping of temperature from south to north.

The Subarctic Open Lichen Woodland

The more northern subarctic lichen woodland is a handsome landscape mostly unknown to Canadians because of its few settlements and roads (and also very abundant black flies!). Northern stands of scattered spruce and jack pine, accompanied by balsam fir in Quebec, form attractive open-canopied areas carpeted with yellow, green and light grey lichens. Recently burned areas are covered with birch, blueberries and other small evergreen shrubs. Larch is common in low marshy areas while shallow-rooted black spruce populates the surface of frozen and uplifted bogs known as peat plateaus.

The Closed Crown Forest

The southern belt of closed crown forest occupies a milder climatic zone where the trees grow taller and closer together to form closed-canopies beneath which plentiful mosses, herbs and shrubs thrive. This is the commercial forest that feeds the sawmills and pulp mills. In the western part of the closed crown forest area (the northern part of British Columbia and the Rocky Mountain Foothills of Alberta) prominant tree species include white spruce, black spruce, birch and poplar. Further east in the Precambrian area of Ontario and Quebec, the predominant tree species are jack pine and black spruce. There are also large flatter areas of particularly productive forests of spruce, fir and pine.

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Mammals of the boreal forest

On the southern border of the closed crown forest, fertile soil supports a richer combination of trees including white spruce and poplars. Further to the east there are sugar maple, yellow birch, red pine and white pine. These bands or areas of mixed woods show the affect of the increase in precipitation as one moves from west to east. This not only allows for greater numbers of tree species but also the greater prominence of balsam fir, a most important member of the forest from Lake Superior to Newfoundland and Labrador.

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Birds of the boreal forest

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Drawing of the plants of the boreal forest

Disturbances

The boreal forest is destroyed by fire, and created by it. Flames ravage the forest regularly, leaving a landscape of burnt trees and blackened earth. From this charred ground, new life emerges: plants suited to the scorched terrain, and trees more robust than the aged ones they replace. Fire means renewal in the boreal forest, a central part of the life cycle as ancient as the forest itself. For most of the 20th century, people hoped to eliminate fire from the forest. Distressed by the loss of valuable timber, governments and lumber companies fought every accessible forest fire. Now, the fire-fighter's priorities have become the protection of human life and property and the preservation of the most commercially valuable stands. In areas where the fire is too hard to get at, fire is allowed to take its course.

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Forest fire

The boreal forest is a patchwork of different tree populations that burn naturally at different intervals. For jack pine it happens every 15 to 35 years; certain spruce forests are hit by fire every 50 to 100 years; and some red or white pine stands may burn only once every two centuries. At the other extreme, aspen burns naturally every three to five years. New aspen grows from the roots of the old trees, even if those trees are charred. Similarly, black spruce and lodgepole pine can keep live seeds in their cones for years; seeds that are released when fire kills the trees themselves. Then a new life succession begins using nutrients produced by the fire from the remains on the forest floor. The fireweed is generally the first to grow from the charred land.

Lightning accounts for about 85 percent of the 2.8 million hectares burned annually. People, including careless campers and smokers, cause the rest. The fires caused by people are more numerous, but burn a smaller area than those ignited by lightning.

Wind is the ally of the fire. Wind blowing through the forest dries and makes it more flammable. Wind fans the fires already burning and carries sparks over vast areas. Wind is one of the reasons fires are generally worse during the day than at night -- by day, winds are stronger, temperatures are higher and there is less humidity.

A Forest Fire Weather Index has been created which links weather and forest conditions to provide daily local ratings of forest fire risk. All provincial and territorial forest firefighting agencies have been united since 1982 in the Canadian Interagency Forest Fire Centre, located in Winnipeg. This agency arranges the transfer of fire-fighters, equipment and aircraft across provincial and even international boundaries.

The job of controlling fires comes down to people doing hot, dangerous work on the ground. In a direct attack, fire-fighters with shovels, portable pumps, hoses and bulldozers try to extinguish the flames on the spot. If the fire is too hot or spreading too quickly, crews use the indirect approach of a back fire or burnout. A strip of land is burned ahead of the fire in the hope that when the fire reaches the burnt strip the fire will die out. Rain has always been and remains the fire-fighter's best friend. Perhaps the next best thing is the water bomber, such as the Canadair CL-215. Introduced in 1967, it is the only plane specifically designed to skim over the surface of a lake and pick up water; it can pick up more than 5000 litres of water in 10 seconds and drop it over a fire in one second.

Forest Fires Across Canada

There are about 9000 forest fires recorded annually in Canada. Most are small, burning just a few hectares. Some are huge, raging for weeks and consuming 100 000 hectares or more. (One hectare is equal to 2.47 acres). An average of 2.1 million hectares is burned every year, virtually all of it in the boreal forest (the eastern hardwoods and the west coast rain forest are almost immune to fire). In comparison, about 800 000 hectares of Canadian forest are cut down every year.

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Figure 4. Forest Fires Across Canada

Insect infestation

Insect infestation is a significant disturbance in the eastern and central regions of Canada where outbreaks of spruce budworm cause extensive damage to commercially valuable stands of fir and spruce. Between 1980 and 1993 over 6.6 million hectares of forest land in the eastern boreal forest was affected by the spruce budworm. Had it not been for extensive aerial spraying the affected area would have been much more extensive.

Boreal Disturbance Chart

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Figure 5. Boreal Forest Disturbances

Shaping Canada's History

Creating Employment and Wealth for Canadians

The global population explosion of the past half-century has pushed the demand for lumber and pulpwood to levels unimaginable 70 or 80 years ago. At the same time, technology has provided loggers with greater forest access and more efficient harvesting tools. Axes have been replaced by chain saws, which in turn have often been replaced by mechanical harvesters capable of gathering thousands of trees per day. Logs that were once moved to the mills along waterways are now trucked year round. An estimated 50% of Canada's vast boreal forest is now accessible by highways and logging roads.

Forestry is Canada's largest natural resource industry. Our forest products trade surplus is close to the combined surpluses for agriculture, energy, fisheries and mining. Our nation is the largest exporter of wood products in the world. The forest industry is a major contributor to employment. In 1993 it provided an estimated 352 000 direct jobs in silviculture, logging, wood industries, and paper and allied products, as well as thousands of indirect jobs through its purchase of goods and services. Many Canadian communities rely entirely or heavily upon the boreal forestry industry for their survival. These forest-dependent communities have limited alternate economic and employment opportunities and are vulnerable to the industry's seasonal and cyclical changes.

Tourism

Although forestry is the main industry, many other economic activities take place in the boreal forest region. These include mining, oil and gas extraction, hunting, trapping, fishing, tourism and recreation and also the service industries which support these activities. As well, the rivers and lakes are a source of water and power for much of the Canadian economy. The boreal forest also provides the basis for subsistence activities in some rural areas. In addition, a significant number of Aboriginal communities rely upon the boreal forest ecosystem to sustain their local economies, social structures and cultural values.

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Canoing in the boreal forest

The boreal forest provides Canadians with far more than jobs and a healthy trade surplus in wood and paper products. For millions, it is a recreational and spiritual refuge, a place where they can hike, canoe, camp, fish and take photos. It is even a place just to look around and breathe in the fresh air. Its lakes, trees and rock formations, its birds and animals are the base for hundreds of millions of dollars' worth of tourism.

Forest Sector

One in every 16 Canadians depends on the forest sector for employment. In 1999, the logging industry employed 58 000; the forest service industry, 22 000 people; wood industries, 154 000; and the pulp and allied industries, 118 000. Together they accounted for 352 000 direct jobs. (Data from The State of Canada's Forests, 1999-2000, published by Canadian Forest Service, Natural Resources Canada)

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Sawmill

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Figure 6. Labour Force, Boreal Region, 1981 to 1991

Cumulative Impacts That Threaten Sustainable Use

Human activities place increasing pressures on the boreal forest ecosystem. Stresses are greater in some regions than in others. It is the intensity and combination of these stresses that, over time, may ultimately test the resilience of the ecosystem.

Forest management practices such as fire suppression, insect control, clearcutting, and tree planting occur in commercially available forests. There is increasing concern that these practices may, over the long term, shift species composition, reduce species and genetic diversity, and increase the forest's vulnerability to other disturbances.

Forest land may be removed permanently for alternative uses such as roads, power and pipeline corridors, hydroelectric development, mining, urban development, and recreational use. Large-scale land use changes such as major hydroelectric project can alter ecosystem function, eliminate wildlife habitat, and otherwise profoundly affect wild species and their populations. The life styles of the Aboriginal inhabitants of an area may be affected as well. The additive effects of even small-scale land use changes can result in substantial losses and disruptions over time.

Herbicides, pesticides, and contaminants in emissions from industrial processing also affect the ecosystem. Acidic deposits from the long range transport of airborne pollutants have affected aquatic life in many lakes in Ontario and Quebec. These pollutants may also weaken the vigour and growth of trees in sensitive areas of the boreal forest. Many of these airborne contaminants come from sources outside the boreal forest.

Endangered Species

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Whooping crane and wood bison

The endangered whooping crane (Grus americana) and threatened wood bison (Bison bison athabascae) are boreal species designated at risk by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

Species Comparison in Harvested and Non-harvested Areas, Boreal Ecozones

A shift from coniferous to broadleaf species in harvested areas of the boreal forest may reflect the impact of harvesting replacing fire as an agent of disturbance. The geographic variation in species distributions also contributes to the differences between harvested and non-harvested areas.

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Figure 7. Species Distribution in Harvested and Non-harvested Areas

Actions and Policies to Ensure Sustainable Development

Current management of the boreal forest is largely in the hands of the provinces. Each province has its own legislation, regulations and policies for allocating harvesting rights and forest management responsibilities such as monitoring harvesting and encouraging sound logging and reforestation practises. The federal government, which controls just over 5% of the boreal forest, contributes in the areas of scientific research, economic development, international trade and relations and pesticides registration. Both levels of government protect significant tracts of forest from logging in national and provincial parks, ecological reserves, wildlife sanctuaries, conservation areas and forest preserves. In addition, timber harvesting on commercial forest lands is now excluded, by policy, from sensitive areas such as shallow or rocky soil, steep slopes, and buffer zones along roads, lakes and watercourses.

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Figure 8. Land Ownership in the Boreal Forest

Most of Canada's boreal forest land is publicly owned. The provinces hold the largest share. Federally-owned forest is held mainly in federal parks and reserves, and in the northern territories. A very small portion is privately owned.

To achieve Canada's goal of sustainable forest development, a wide range of complex issues must be dealt with. During the early 1990s, concerned forestry officials set out to develop a master plan that would ensure a co-ordinated, ecological approach to forest management in Canada. The product of that undertaking is the National Forest Strategy. It was endorsed in 1992 by all levels of government as well as by the representatives of industry, Aboriginal peoples, educational and conservation groups. The strategy views the boreal forest as being as important to the hiker, the ecologist and the everyday citizen as to the lumber baron and the commodities trader. It encourages any research that might add to the knowledge of how forest ecosystems operate and how their biodiversity and vigour can be protected and enhanced.

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Figure 9. Protected Areas and Commercial Forest Land

Sustainable Forests: a Canadian Commitment

Canada Forest Accord, 1992 states Our goal is to maintain and enhance the long-term health of our forest ecosystems, for the benefit of all living things both nationally and globally, while providing environmental, economic, social and cultural opportunities for the benefit of present and future generations.

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Figure 10. Forest Management Planning Framework in Canada

Securing a Sustainable Future

One objective of the National Forest Strategy is to provide researchers with an extensive living laboratory. Consequently, ten model forests have been established across Canada, five of which are in the boreal forest. These are official research preserves with each representing a different social, economic and environmental milieu. A major purpose of the model forests is to assist in developing a comprehensive national set of criteria to measure Canada's progress toward sustainable forestry.

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Figure 11. Model Forests

Innovative approaches to forest management are being developed and tested under Canada's Model Forest Program. Five of ten model forests across Canada are located in the boreal forest. Following the Canadian example, other countries are also developing a network of sites.

By the year 2000, a network of protected areas will be in place that is representative of forest ecosystems in Canada. At both federal and provincial levels, ecological classification and inventories are contributing to an understanding of the composition and structure of the boreal forest ecosystem.

There are several encouraging trends in Canadian forest management. One is a trend towards increased expenditures on forest management. As well, there appears to be a decline in the use of of chemical pesticides and herbicides in favour of biological control methods. In addition, the pulp and paper industry is decreasing its use of chlorine, dioxins and furans in response to government regulations and the introduction of new technologies.

At the international level, Canada has committed itself to the international agreements on biological diversity, climate change and forestry principles signed at the United Nations Conference on Environment and Development, June 1992.

The cumulative and long-term effects of human activities on the boreal forest remain uncertain, but the outlook is encouraging. All stakeholders are being encouraged to take an integrated, ecosystem approach to sustainable forest management. Current research activities, policies and actions are moving us in the right direction. The obligations are simple: The Canadian forest community and Canadian society as a whole share the responsibility for preserving the integrity of our boreal forest heritage, not only for our present use, but for the use of future generations, and for the health of our global environment.

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Figure 12. Forest Management Expenditures in Canada, 1977 to 1992

A significant increase in expenditures on silviculture and protection over the past decade reflects a trend to more intensive forestry, on a smaller land base, to accommodate multiple forest uses and values.

References

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