For most of the 20th century

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 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 5,000 litres of water in 10 seconds and drop it over a fire in one second.