|
There are about 9000 forest fires recorded annually in Canada, however, 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.
Lightning accounts for about 85 percent of the 2.1 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 it 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.
Forest Fires in the Boreal Forest
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.
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.
Fighting the Fires
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.
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.
Descriptions for each of the major forest fires shown on the map are found
in the document Major
Forest Fires.
|
