Ministry of Forests and Range, Wildfire Management Branch
Prescribed Fire
Prescribed fire is the knowledgeable and controlled application of fire to a specific land area to accomplish planned resource management objectives. These fires are managed in such a way as to minimize the emission of smoke and maximize the benefits to the site.
When the B.C. Forest Service was established in 1912, it emphasized the prevention and control of forest fires in the province. The success of aggressive fire suppression has resulted in a dangerous build-up of forest fuels, tree encroachment on grasslands, and in-filling of the once open, dry forests of the southern interior. More recently, forest, range, and wildlife managers have been using fire as a land management tool. Prescribed fire can help grow better forests, create better habitat for wildlife and domestic animals, reduce the intensity of naturally occurring wildfires, and return an integral process to some ecosystems.
Fire in Nature
Fire is a natural, normal process in many ecosystems. It is beneficial and necessary to maintain a healthy forest and the diversity of plant and animal life. Through evolution and exposure to wildfires, many plants and animals have adapted to fire, and in fact actually depend on it.
Trees like Western Larch, Douglas fir and Ponderosa Pine have developed bark so thick that it insulates the living tissue, allowing them to survive surface fires. Fire naturally occurred in stands of these trees every 5 to 20 years and kept the forest floor relatively clean of combustible material. Wildfires burn in varying intensities across a landscape, thereby increasing biodiversity by changing the composition and density of forests.
Lodgepole pine needs fire, to an extent, to disperse its seeds, even though the trees are usually killed by it. Heat from a fire melts the resinous material that holds the cones' scales together, thereby releasing the seeds for a new forest.
Fires release the nutrients locked up in slowly decaying logs and other organic material. Fires can open up a thickly-treed forest, letting in the sunlight to encourage the growth of shrubs and grasses - forage for wild and domestic animals. Cattle, moose, deer and elk benefit from the browse created by fire.
Naturally occurring fires also help to keep insects and disease in check by killing the pathogens infecting a stand. This is critical when you consider that in recent years, more than five times as much timber has been lost to insects and disease than has been consumed by wildfire.
Fire as a natural disturbance is incorporated into the Biodiversity Guidebook, an ecosystem management approach that aims to provide suitable habitat for all native species. In this sense, natural fires are classified as either:
- Stand-Initiating events - significantly alters an ecosystem such that successional processes will form a new plant community with a different structure/composition than its predecessor.
- Stand-Maintaining events - fairly frequent occurrences serving to maintain an ecosystem at a particular successional stage.
Fire and Forestry
Before harvesting can take place on forested land, a site plan must be made by a forester. This plan identifies the site conditions and determines the best method of harvesting and treatment to prepare the site for a new forest. Fire is sometimes used as a pre-planting treatment: burning returns nutrients to the soil for a period of time and keeps down weeds (reducing the need for herbicides) and other vegetation long enough to let tree seedlings become established.
Planning a Burn
Resource managers need to have a sound understanding of fire behaviour and its short/long term effects on the environment. In addition, different ecosystems (even different plant species) respond to fire in a different way. Optimum burning conditions are needed to reduce the chance of a fire's escape as well as reducing fuel loading without damaging the forest floor by excessive heat, which could result in erosion.
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