Prescribed burn

A controlled or prescribed burn, also known as hazard reduction burning, backfire, swailing, or a burn-off, is a wildfire 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.There are two basic causes of wildfires. One is natural (lightning) and the other is people. Controlled burns have a long history in wildland management. Pre-agricultural societies used fire to regulate both plant and animal life. Fire history studies have documented periodic wildland fires ignited by indigenous peoples in North America and Australia.Back burning involves starting small fires along a man-made or natural firebreak in front of a main fire front. Back burning reduces the amount of fuel that is available to the main fire by the time that it reaches the burnt area.Another consideration is the issue of fire prevention. In Florida, during the drought in 1995, catastrophic wildfires burned numerous homes. But forestry managers in the Florida Division of Forestry noted that the underlying problem was previous cessation of controlled burning, resulting from complaints by homeowners. Each year additional leaf litter and dropped branches increased the likelihood of a hot and uncontrollable fire.In addition to forest management, controlled burning is also used in agriculture. In the developing world, this is often referred to as slash and burn. In industrialized nations, it is seen as one component of shifting cultivation, as a part of field preparation for planting. Often called field burning, this technique is used to clear the land of any existing crop residue as well as kill weeds and weed seeds. Field burning is less expensive than most other methods such as herbicides or tillage, but because it produces smoke and other fire-related pollutants, its use is not popular in agricultural areas bounded by residential housing.The conflict of controlled burn policy in the United States has roots in the historical campaigns to combat wildfires and to the eventual acceptance of fire as a necessary ecological phenomenon. The notion of fire as a tool had somewhat evolved by the late 1970s as the National Park Service authorized and administered controlled burns. While the methodology was still relatively emergent the Yellowstone fires of 1988 struck, which significantly politicized fire management. The ensuing media coverage was a spectacle that was vulnerable to misinformation. Reports drastically inflated the scale of the fires which stigmatized politicians in Wyoming, Idaho, and Montana to believe that all fires represented a loss of revenue from tourism. Partially as a result of millions of dollars lost in estimates, stricter data recording was enforced and thresholds were established for determining which fires must be suppressed. Paramount to the new action plans is the suppression of fires that threaten the loss of human life with leniency toward areas of historic, scientific, or special ecological interest. Since 1988, many states have made progress toward controlled burns but with a proclivity toward forgetfulness between fire events. Senators Ron Wyden and Mike Crapo of Oregon and Idaho have been moving to reduce the shifting of capital from fire prevention to fire suppression following the harsh fires of 2017 in both states.Depending on the context and goals of a prescribed fire, additional planning may be necessary. While the most common driver of fuel treatment is the prevention of loss of human life, certain parameters can also be changed to promote biodiversity and to rearrange stand ages appropriately. The risk of fatal fires can also be reduced proactively by reducing ground fuels before they can create a fuel ladder and begin an active crown fire. Predictions show thinned forests lead to mitigated fire intensity and flame length compared to untouched or fire-proofed areas. Furthermore, low-intensity fire treatments can be administered in places where mechanized treatments such as disc harrowing cannot. In the interests of conservation, electing for a mixed mosaic of unburnt islands within the targeted area maintains biodiversity and provides cover for wildlife. Because of this, some suggest fuel reductions of about 75% to be sufficient, though each burn plan should have its own target set by ecological and management goals. In some areas where grasses and herbaceous plants thrive, species variation and cover can drastically increase a few years after fuel treatments.The controlled burning or swailing of heathland is used in the United Kingdom and other countries as a conservation tool. In Scotland it is known as muirburn. Often it is used as a tool for creating fire breaks to reduce the risk of dangerous outbreaks but is also an important mechanism for preventing succession to woodier vegetation and plays an important role in the life cycle of heather species. Red grouse eat heather shoots and as grouse shooting has long been an expensive sport the landowners need to ensure a good crop of grouse so each year parts of the moor are burned of old heather to cause fresh shoots.Controlled burns on Australian or USAAA savannas can result in an overall reduction of greenhouse gas emissions. One working example is the West Arnhem Fire Management Agreement, started to bring 'strategic fire management across 28,000 square kilometres (11,000 sq mi) of Western Arnhem Land' to partially offset greenhouse gas emissions from a liquefied natural gas plant in Darwin, Australia. Deliberately starting controlled burns early in the dry season results in a mosaic of burnt and unburnt country which reduces the area of stronger, late dry season fires. Also known as 'patch burning'. To minimise the impact of smoke, burning should be restricted to daylight hours whenever possible.