Controlled burn

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Prescribed or controlled burning is a part of forest management. Fire is a natural part of forest ecology and controlled fire is a useful tool for foresters.

Controlled burning stimulates the germination of some highly desirable forest trees, thus renewing the forest. Some seeds, such as sequoia, remain dormant until fire breaks down the seed coating.

Another consideration is actually fire control. In Florida, during the drought in 1998, catastrophic wildfires burned a number of homes. But forestry managers note that the real problem was that controlled burning had mostly ceased in the area, due to complaints by homeowners. Each year additional leaf litter and dropped branches increased the likelihood of a very hot and uncontrollable fire.

"Stopping control burning does NOT stop the burning, just the control!" said Dave Sumpter of the Florida Forest Protection Bureau.

George D. Kessler, professor of forestry, and extension forester at Clemson University notes that controlled burning reduces fuels, improves wildlife habitat, controls competing vegetation, improves forage for grazing, improves accessibility, helps control tree disease, and perpetuates fire dependent species. In old growth longleaf pine forest, it helps maintain habitat for endangered Red-cockaded Woodpeckers in their sandhill and flatwoods habitats.

Anyone planning a controlled burn should check with fire control authorities for regulations and permits. The party responsible must delineate the intended time and place. Obtaining a permit does not relieve one of liability if the fire gets out of control.

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Controlled burns are commonly ignited using a tool known as the driptorch, which allows a steady stream of flaming fuel to be directed to the ground as needed. Variations on the driptorch can be used such as the helitorch, which is mounted on a helicopter, or other improvised devices such as mounting a driptorch-like device on the side of a vehicle. A pyrotechnic device known as the fusee can also be used in ignition.

For the burning of slash, waste materials left over from logging, there are several types of controlled burns. Broadcast burning is the burning of scattered slash over a wide area. Pile burning is gathering up the slash into piles before burning. These burning piles may be referred to as bonfires. High temperatures can harm the soil, damaging it physically, chemically or sterilizing it. Broadcast burns tend to have lower temperatures and will not harm the soil as much as pile burning, though steps can be taken to treat the soil after a burn. In lop and scatter burning, slash is left to compact over time, or is compacted with machinery. This produces a lower intensity fire, as long as the slash is not packed too tightly. However, soil may be damaged if machinery is used to compress the slash.

In addition to forest management, controlled burning is also used as an agricultural practice as a part of field preparation for planting. The controlled burn is used to clear the land of any existing crop residue as well as kill weeds and weed seeds. A controlled burn is less expensive than most other methods such as herbicides or tillage but because it does produce smoke and other fire related pollutants, its use is not popular in agricultural areas bounded by residential housing. In the United States, controlled burning is a legislative and regulatory issue at both the Federal and state levels of government.

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