A controlled or prescribed burn, also known as hazard reduction burning, backfire, swailing, or a burn-off, is a fire set intentionally for purposes of forest management, farming, prairie restoration or greenhouse gas abatement. A controlled burn may also refer to the intentional burning of slash and fuels through burn piles. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters.

Hazard reduction or controlled burning is conducted during the cooler months to reduce fuel buildup and decrease the likelihood of serious hotter fires. Controlled burning stimulates the germination of some desirable forest trees, and reveals soil mineral layers which increases seedling vitality, thus renewing the forest. Some cones, such as those of lodgepole pine and sequoia, are serotinous, as well as many chaparral shrubs, meaning they require heat from fire to open cones to disperse seeds.

In industrialized countries, controlled burning is usually overseen by fire control authorities for regulations and permits.

 

Note:   The above text is excerpted from the Wikipedia article Controlled burn, which has been released under the GNU Free Documentation License.