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Editor's Note: This article, part of a regular series about the Hoosier National Forest, was written by Ben Ingram, a fire engine operator.
Smokey Bear has done an excellent job telling people that fire is bad, but some ecosystems require fire. The Hoosier National Forest landscape has historically burned. So how do we create a healthy forest or grassland ecosystem in the absence of wildfire? There are several answers to this question. One is prescribed burning.
What is Prescribed Burning?
Prescribed burning is a forest-management tool. It occurs when fire is purposely started and managed under very controlled conditions.
By mimicking fire that historically occurred throughout forest landscapes, it helps maintain the native vegetative composition of a forest or grassland ecosystem.
Hazardous fuels: Storms, freezes and high-wind events are common occurrences and often result in broken tree tops and downed trees. These fuels accumulate over the years, increasing the hazardous fuel buildup on the forest floor. Prescribed burns help reduce the excessive forest fuel buildup. During a prescribed burn, the fuels are burned under controlled conditions and monitored for several days following the burn.
Wildlife habitat: Wildlife openings are a great source of food and cover for many wildlife species found in the forest. Over time, the openings become cluttered with dead grass. The thatch layer thickens, making it difficult for many small wildlife species to travel throughout the opening. Prescribed burns help remove the thatch layer and open the ground to sunlight.
Site preparation and nutrient recycling: Fire eliminates the majority of leaf litter and thatch found in forest and wildlife openings. As sunlight is introduced into the opening floor, new sprouts begin to grow. Burning provides a quicker method for nutrient release than the slower processes of decomposition.
Ecosystem restoration: The oak-hickory forest historically found in the Hoosier National Forest has shifted to a mid-story and understory dominated by maple, beech, white pine and other fire-sensitive species. With such a dense mid-story and understory, oaks have a difficult time regenerating. Oak seedlings need a certain amount of sunlight to survive and prescribed burning helps thin out fire-sensitive species that shade the forest floor.
Managing a Prescribed Burn
A burn plan is written for every area to be burned. During planning, several factors are considered, such as burn objectives, weather, topography, crew and equipment needs, fuel types and conditions, boundary lines and smoke dispersal. Most important is public and firefighter safety.
The burn plan is also used to predict certain fire behavior and characteristics that will help meet forest-management objectives. Flame height, rate of spread, flame intensity and burn duration are considered in trying to mimic the historic low intensity fires.
Before burning begins, all parameters are checked to ensure that weather and fuels are in proper prescription. The burn location is called into the National Weather Service and a spot weather forecast is delivered. Weather is also monitored on the ground to guarantee the burn is still in prescription. Fuel data is gathered from a local remote automatic weather station and monitored throughout the entire burn day.
Prescribed burns are typically divided into two or more sections called divisions. Each division is assigned a certain amount of fire personnel and equipment. Personnel are divided into two main groups per division, the ignition crew or the holding crew. The ignition crew consists of fire personnel with drip torches. Occasionally a helicopter is used for interior lighting after the perimeter is secured. The holding crew's job is to ensure the burn does not escape the burn lines.
A test fire is ignited to check how the burn will carry across the landscape. If the test burn shows promise, then the burn will continue, otherwise the burn will be stopped and attempted another day. Once the burn begins, each division continues spreading fire along their burn lines.
As the burn progresses, holding crews follow along, monitoring the lines until they have cooled down. After the entire burn perimeter has been lit, a helicopter may be used for aerial ignitions in the interior of the burn. Once ignition is completed, the area is monitored until either adequate precipitation has occurred or until all heat along the burn line has dissipated.
Not all of a prescribed burn area will be blackened. The purpose is to create a mosaic burn that removes most of the undesirable vegetative species and allows easy passage for a majority of wildlife species. As vegetation begins to grow in the spring, the burn area will be less obvious to the forest visitor.
Upcoming Prescribed Burns
Forest officials plan to burn approximately 3,000 acres of the forest in 2010 for ecosystem restoration and wildlife habitat improvement.
For additional information about the Hoosier's prescribed burning program, contact Mike Davis at 547-9247.