Forest Fire_Content Page_Prescribed Fire

Prescribed Fire

Prescribed fire is the intentional application of fire to a specific pre-planned area, under specific environmental conditions, to accomplish planned land management objectives. Without the use of prescribed burning as a management tool, Wisconsin could lose many of its native grassland, wetland and savanna plant communities.

Note: The DNR does not conduct prescribed burns on private property. For contractors that do, visit the Wisconsin Prescribed Fire Council's list of contractors [exit DNR].

History of fire in Wisconsin

Fire was as much a part of the pre-settlement Wisconsin environment as rain, drought and the passing of the seasons. For thousands of years, wildfires occurred naturally through lightning strikes or were set by Native Americans for the purpose of preparing settlements and attracting game species. Because frequent fire played a significant role in the development of much of Wisconsin's native plant communities, many plant and animal species now depend on fire for their continued existence. These periodic fires have been all but eliminated in Wisconsin in the last 150 years.

Fire is a natural and necessary component of ecosystems such as native prairies and oak openings and pine and oak barrens. Periodic fire is required for regeneration and growth of fire-adapted species within these systems. Land managers use prescribed burning to assist in restoring and maintaining these rare plant and animal communities.

Prescribed fire versus wildfire

Prescribed burns differ greatly from wildfires in many ways. Prescribed burns are set intentionally after considering the safety of people and property, ideal weather conditions, wind direction and smoke management. Wildfires are uncontrolled and unplanned and often occur on days where weather and fuel conditions are primed for large fire development. They also have the potential to do great harm to people, structures and natural resources. While a prescribed burn occurs under conditions conducive for low to medium fire intensity (e.g. flames that will clear mid-story brush and open up a woodland area), wildfires can grow to an intensity level capable of completely burning an entire forest stand.

Benefits

Fire and wildlife have a historic and complex relationship in grassland, wetland and savanna communities. Prescribed fire is rarely lethal to most wildlife, yet has a profound effect on habitat by increasing the number of native plant and animal species present food sources for wildlife. The wildlife species that benefit most from prescribed fire are those that rely on open habitat in one or more stages of their life cycle. Examples of these animals are grassland birds, sharp-tailed grouse, waterfowl and pheasant. Prescribed burns also help to stimulate flowering herbaceous plants (forbs)—a source of food for white-tailed deer. Additionally, wildflower abundance and diversity support a wide variety of insects and other invertebrates, a food source that provides benefits all the way up the food chain.

Some specific advantages of prescribed burns include:

  • stimulating prairie grass growth and improve habitat for upland game and waterfowl;
  • creating pockets of open water for waterfowl amidst cattails proliferating in low areas;
  • stimulates the growth of wildflowers, which attract insects—a vital food sources for young game and non-game grassland birds;
  • improving cover type for grassland nesting birds such as pheasants, and spur native vegetative growth for songbirds; and
  • creating open pockets of bare ground, increasing diversity and richness of ground foraging, seed-eating small mammals and birds.

Benefits to plants

Many of Wisconsin's native plants developed adaptations to survive in a fire-prone community. For instance, fire-adapted prairie grasses and flowers develop deep roots and buds beneath the soil, enabling them to withstand the fire, while shallow-rooted non-native plants succumb to the heat. But these plants do not simply tolerate fire better than others, they actively benefit from fire. For instance, by removing accumulated leaf and grass litter and invading brush, fire stimulates the growth of native herbaceous species and maintaining the open character of these systems. Prescribed fire also returns nutrients to the soil, which in turn benefits the entire plant community.

Without fire, the structure and species composition of a plant community changes, providing the opportunity for invasive plants to overwhelm the site and allowing faster-growing species (e.g. maple) to shade out the slower-growing seedlings (e.g. oak). These communities would become uninhabitable to many of the wildlife species that depend on it, especially those that have very specific habitat requirements. Maintaining the integrity of these plant communities is especially crucial in critically rare ecosystems such as pine or oak barrens and oak savannas. Conducting prescribed burns in these systems ensures their continued integrity for future generations.

Some specific advantages of prescribed burns include:

  • maintaining the vertical structure and/or open nature of fire-dependent plant communities;
  • creating open pockets of bare ground, increasing seed-to-soil contact for plant species;
  • reducing competition for slower-growing native trees that would otherwise be shaded out;
  • recycling nutrients from burned fuels back into the soil; and
  • reducing the presence of fire-intolerant non-natives by exploiting their sensitivity to heat.

Domestic land management

Prescribed burning is one of the least expensive and most environmentally-sound ways to accomplish this practice. Removing the layer of dead grass ("thatch") ensures better seed-to-soil contact for planting. Nutrients are released into the soil during burning to further enhance the re-establishment of a new forest, crop planting or Conservation Reserve Program (CRP) planting. Research has shown forage for livestock can be improved in quality and quantity with timely burning. For instance, protein content increases significantly in many grass species in the growing season after a burn.

Reducing wildfire risk

This objective is especially important in forests in proximity to urban areas. Reducing fuel loads is one of the most effective elements of any fire prevention and management program. Reducing brush in the mid-story of forests reduces the possibility of brush acting as "ladder fuels" for fire to reach the crowns of trees. Additionally, by reducing the fuel loading in open communities like prairies and wetland, fire intensity (flame height and rate of spread) is reduced and fires are easier to control and suppress.

DNR prescribed burning

To meet specific land management objectives, prescribed fire is conducted under weather conditions conducive to creating the desired fire behavior (intensity). These weather conditions are less extreme than when most wildfires usually occur, leading to fire behavior that is easier to manage and suppress, should the need arise.

Prescribed burning typically occurs during the early spring (March through May) and late summer/fall (July - November), but can occur beyond these periods if conditions allow. These are the periods when desirable plant and animal species are less active. In the spring, this typically occurs shortly after the snow has melted, but before significant green-up has occurred. In the late summer/fall, this is typically after plant moisture levels have decreased and some good hard frosts have occurred before winter precipitation.

Safety first

All DNR prescribed burn crew members receive extensive training for prescribed burning and suppression. Before any burn is conducted, experienced and trained personnel assess the area to determine the wind direction and speed, relative humidity, "fuel" (plant) moisture and safety considerations necessary to conduct a burn safely. Qualified personnel manage fire behavior through the use of comprehensive planning and specialized fire equipment. Local police and fire officials are notified when and where burns will take place, so they can respond to people who report that they are seeing smoke from an area.

Before a burn takes place, the crew is briefed by the burn boss [video exit DNR] on the plan for safely executing the burn.

Smoke management

Smoke control is an important aspect of any prescribed burn plan. Prior to burning, experienced personnel carefully review the burn area and the proximity of houses, roads and other smoke sensitive areas. This information is then incorporated into the plan and the prescribed burn occurs when favorable conditions (e.g. wind) minimize the amount of smoke reaching these areas.

Permits and planning

Before conducting any prescribed burns in Wisconsin, obtain proper DNR burning permits (if necessary where you live) or consult your local municipal or township officials for any regulations or ordinances related to prescribed burning.

Always keep an eye on the changing weather conditions and stay within the specified burn times and size limitations as indicated on the permit or by the daily restrictions. Upon DNR inspection, special burning permits may be issued for burning outside the restricted burn times for prescribed fires exceeding the maximum size limit. Contact your local DNR Ranger Station or fire control dispatch office [PDF] for more information.

Burn plans

Prescribed burn plans generally involve a written document that addresses a number of important factors. They are crucial to a successful and safe burn, as they provide all necessary information in one place, should the Burn Boss/landowner need it immediately during the burn. The plan should clearly describe the existing vegetation on the burn area and the desired future condition. The plan should also spell out the specific weather conditions and ignition patterns required to achieve the desired fire behavior. Any issues relating to adjacent lands, communities, structures, roads, smoke management and traffic control needs should be addressed. Finally, the plan should identify the people and equipment needed to safely complete the burn and include a detailed contingency plan (including contact information) for reacting to any emergency. Refer to this sample burn plan template [PDF exit DNR] for ideas on what to include in your plan. Additional resources are also available to make your burn as safe and effective as possible.

Weather and fuel conditions

In addition to key weather elements like temperature, relative humidity, wind speed and direction, other weather and fuel factors should be considered. Prescribed burns should not be conducted during drought conditions due to the additional stress it places desirable plant and trees species and the increased risk of extreme fire behavior. Be sure to check the drought monitor index for Wisconsin [exit DNR] and the current fire danger levels for your area. Elevated fire danger levels may lead to restrictions on prescribed fires, and under extreme fire danger levels, prescribed burning may be temporarily banned throughout the entire state. Before you consider burning on any day, use the previous link and click on your county to see if any restrictions are in place.

Additionally, prescribed burns may be detrimental to any smoke-sensitive areas such as schools, airports, hospitals and retirement communities. Be sure to know where your smoke is headed and choose a day where the wind direction carries the smoke away from these areas. Avoid burning on days where an air quality advisory is already in place, as smoke is less likely to disperse effectively on those days. You can see the current air quality index for each county and see if there is an advisory in your area.

Landowner resources