Bordered to the north by treeless arctic tundra and to the south by temperate forest or grassland, the zone includes 3 ecologically and structurally distinct subzones: northern boreal woodland, with widely spaced coniferous trees, hardy low shrubs and sun-loving lichen carpets; main boreal forest, with closely spaced evergreen and deciduous trees, and shade-tolerant shrubs, herbs and feathermoss carpets beneath them; and southern boreal forest, similar to the latter but containing occasional temperate tree and other plant species.
There are also 2 transitional subzones: hemi-arctic forest-tundra, a mosaic of taiga and tundra vegetation along the northern margin; and hemi-boreal aspen parkland (west) and northern conifer-hardwoods forest (east), mosaics of boreal and temperate vegetation along the southern margin. The subzones and transitional subzones are correlated with warmer climates from north to south but embracing a wide east-west range of annual precipitation.
In the eastern Appalachian and the western Cordilleran mountain systems, the boreal forest merges with subalpine forest, which extends southward at climatically similar elevations, yielding upslope to treeless alpine tundras. Lightning- and human-induced fires burn vast areas of its highly flammable coniferous forest during dry summers, but most of its plant species are adapted to survive fires or to recolonize burn areas quickly. There is a predictable succession of postfire vegetation, often beginning with fireweed, passing through an equally short-lived willow stage, a longer shade-intolerant forest stage dominated by aspen, pine or birch, and ending with shade-tolerant climax spruce-fir forest, which persists until the next fire. These postfire successional sequences are frequently interrupted by another fire, and hence return to the fireweed stage well before the climax stage is attained.PERMAFROST occurs in small patches in the southern half of the zone but is virtually continuous over wide areas of its northern half; it effectively prevents subsurface drainage and thus favours wetland vegetation. BLACK BEAR, wolf, beaver, muskrat, varying hare, red squirrel, deer mouse and red-backed vole; important birds include Canada goose, common loon, great blue heron, numerous hawks, owls and ducks, ruffed and spruce grouse, belted kingfisher, gray jay, robin and other thrushes, black-capped and boreal chickadees, several nuthatches, vireos and grosbeaks, and many species of warblers and sparrows. Justly infamous insects include mosquitoes, black flies and sand flies (no-see-ums).
Most of the present range of the boreal forest in Canada was covered by glaciers until 12 000 years ago, hence much of its topography and surficial geology results from glaciation, and most of its soils are young compared with those in unglaciated areas. Global warming and cooling have, historically, caused significant northward and southward migrations, respectively, of the boreal forest. Major extinctions and migrations of boreal forest flora and fauna occurred during glacial advances and retreats, the most being in Wisconsin.
Some climatologists predict that GLOBAL WARMING caused by human-induced increases in greenhouse gas production (eg, carbon dioxide and methane) will force the boreal forest and its associated industries to migrate northward very rapidly in the third millennium, surrendering much of their present range to temperate forest, grassland and arid steppe vegetation and their agricultural analogs.
Author GEORGE H. LA ROI
Links to Other Sites
International Year of Forests, 2011
The United Nations website for the International Year of Forests. 2011. Check out the calendar of international events and the latest news about the International Forest Film Festival.
BOREAS Boreal Ecosystem-Atmosphere Study
Online data from an intensive remote-sensing and field study in the boreal forests of central Canada during the years 1993 to 1996.
An informative overview of the Boreal forest region from Natural Resources Canada.
Canadian Boreal Initiative
The Canadian Boreal Initiative is working with a wide range of conservation organizations, First Nations, industry and other interested parties to link science, policy and conservation activities in Canada's boreal forest.
Beautiful flora and fauna are the stars of this multimedia website dedicated to the protection of Canada’s boreal forests. From the Centre for Conservation of Boreal Biodiversity in Quebec.
Bird Studies Canada
The website for “Bird Studies Canada,” an organization dedicated to preserving wild birds and their habitats. Search this site for the latest information on bird sightings and populations, checklists and maps, species at risk, and more.
This site offers descriptions of mammals, birds, amphibians and reptiles, fish, and plant life found in boreal forest regions. Also includes a glossary of terms related to forestry.
Treeline advances in Canada's Arctic
About research into factors affecting the transition of boreal forest into tundra ecosystems. A Dalhousie University website.
Boreal Forest in the global context
In this article, J. Stanley Rowe urges us to "think like the boreal forest." Click on the link to read more about this concept. From the website "natural SCIENCE."
Forest companies and environmentalists agree to save boreal forest
An article about an agreement between environmental groups and the Forest Products Association of Canada to suspend new logging on 29 million hectares of Canada’s boreal forest. From thestar.com.
The boreal forest
Explore this interactive map of the boreal forest region in Canada. From canadiangeographic.ca.
The Canadian Boreal Forest Agreement
This site provides details about the Canadian Boreal Forest Agreement, which applies to 72 million hectares of Canadian public forests licensed to FPAC member companies. Online papers cover related social, economic, and environmental issues. Click on "Media Centre" and scroll down to the bottom of the page to see an outstanding photo gallery.
Archeology In The Oilsands
An article about the history of research into archeological sites in the vicinity of oil sands exploration and development in northern Alberta.