Prescribed Fire

Image of two prescribed fire crew members, each with a drip torch.

What is fire?

Prescribed fire is an intentionally set wildland fire that is confined within a non-combustable barrier called a fire break, and executed according to an approved plan called a “prescription.”

“Good Fire”?

Prescribed fire has many benefits, some obvious others unexpected. Once you understand how valuable is, you’ll want to add it to your land management toolbox.

First and maybe the most important from the standpoint of a landowner, prescribed fire drastically reduces the risk of catastrophic wildfire on your property. Dead leaves, grass thatch, and woody material; including standing snags, provide fuel for wildfire. Left unmanaged, this fuel builds up to increasingly dangerous levels. Wildfire destroys valuable timber. It can damage or incinerate vehicles and buildings. At it worst, wildfire injures and kills those we love. Prescribed fire burns up this dead fuel in a controlled manner at regular intervals so that it never builds up to the point where it poses a wildfire threat.

Benefits of “Good Fire”

The benefits of prescribed fire extend far beyond wildfire suppression. Among its other advantages, prescribed fire is the most cost effective way to manage woody invasive plant species on your land. The more acres you are managing, the cheaper prescribed fire is use. This is especially true if you have roads and streams that can be used as fire breaks.

Prescribed fire reduces dead feuds to ash which is a great fertilizer. Spring burns have the added benefit of warming up the soil to stimulate germination of native plant seeds. 

Speaking of native plants, by removing invasive plants, native plants the struggled to compete will be able to thrive given more sunlight and less competition for soil moisture and nutrients. The abundance of native grasses, sedges and wildflowers will make your property much more attractive.

Dense shade created by invasive shrubs reduces your woodland’s ability to regenerate itself. This is a particular problem in oak woodlands, where seedlings depend on ample sunlight to sprout and thrive.  While fire can knock back oak saplings, the improved growing conditions allow rapid regrowth. Once oaks get older their corky bark resists fire, hence we refer to them as fire-adapted species.

Seeds that have laid dormant in the soil for years may germinate bringing back diversity you thought lost from your land. Because some invasive plants send out chemicals from their roots that suppress competition, prescribed fire can turn a woodland floor from a dead monoculture into a lively and verdant community.

The seeds of some native species depend on or are stimulated by fire to germinate. This is particularly true of some conifers, where the pine cones only open up and scatter their seeds when heated by low intensity fire.

The increased plant diversity and abundance will increase the number and variety of wildlife that call your property their home.

Finally, many invasive shrubs, like honeysuckle and buckthorn, provide great habitat for disease carrying ticks. The dense shade and relatively high humidity produced by dense shrub infestations, allows tick numbers to skyrocket on your land. Prescribed fire, by killing those invasive shrubs, substantially reduces those tick populations. This great news for your family and pets.

Planning is the First Step

Nobody wants to start a fire that is going to cause damage to their property or that of their neighbors. That is arson. In order to safely control fire it needs to be well planned and properly executed by a qualified burn boss and crew. That all starts with the burn plan.

Failing to plan means planning to fail. That is an old cliche, but it is complete true when applied to prescribed fire. A safe and successful burn starts with creating a solid burn plan. The first step in planning is to clearly state the objectives of the burn. What needs to be accomplished and what will a successful burn look like? This step is critical because without a vision for success, the burn boss and crew will not necessarily be moving in the same direction.

The Plan

A competent plan describes the area to be burned (burn unit); its location, size, boundaries, and topography. Also included is a description of the fuel types, their density and arrangement, which allows for calculation of the fuel loading in the burn unit. In addition to fuel loading, weather conditions can dramatically influence fire behavior. Safe parameters are set for temperature, wind direction and speed, as well as relative humidity and atmospheric stability. Those calculations also make it possible to predict the likely flame height, flame lengths, and rate of fire spread.

An ignition section is created in the burn plan that explains where and how fire will be safely applied to the burn unit in a manner that will meet the objectives of the burn.

Armed with this information the burn boss can determine where fire breaks need to be located and how wide those breaks must be. Additionally, constraints are identified to manage smoke so that it does not cause traffic accidents or sicken neighbors.

Effective planning must identify the resources required to conduct the burn. This includes the number of crews required, as well as the staffing for each crew. It also includes the equipment each crew will need: vehicles, UTVs and ATVs, water, drip torches, PPE, radios and hand tools. The plan includes ensuring adequate supplies of food and drinking water.

The burn plan identifies hazards and exposures that need to be addressed prior to the burn. The plan needs to describes how to address those potential problems.

Finally, because things go wrong, the burn boss needs to include contingency plans to respond if the bad thing happens. This includes ensuring first aid equipment is available, as well as knowing who to call in case of an escaped fire or medical emergency.

Image of a pre-fire briefing.

Preparation, Preparation, Preparation

Once the plan is complete, the next step is making the burn unit safe. That means using natural burn barriers like lakes, streams and rock outcropping; existing man-made barriers like roads and turn grass strips. These must frequently be augmented with constructed fire breaks. Fire breaks can be constructed by plowing soil to turn under plants and leave exposed mineral soil. In more remote locations on difficult terrain, it might mean using hand tools such as fire hoes and polaski tools to remove vegetation down to the mineral soil. Finally, crew members can mow fire breaks close to the soil that it cannot carry fire. They then blow the mown break clear of clippings.

The burn boss walks the burn unit to identify potential problems, such as dead trees near the burn breaks or wet areas that could cause equipment to bog down. Because the crew often creates these breaks weeks, months or even years before the first burn, they rake and blow clean all breaks  again within a day or two of the burn. Likewise, the crew clears fuel from around exposures like bird houses, benches and other sensitive objects.

Burn Day

Burn crew members stage additional water supplies around the burn unit so they can fill up as they move around the burn unit. The crew also establishes staging areas for staging equipment and vehicle parking. Smoke management requires posting roadways to warn drivers. Crew members place warning signs where drivers will see them before they enter areas where smoke may cross the roadway.

Speaking of smoke management, many municipalities require notification of neighboring property owners of the upcoming burn. This might necessitate a postcard mailing, email or placing fliers in nearby doors. Prior notification is a good practice, regardless of regulatory requirements.

Back in the shop, burn bosses and their crews need to make sure that ample equipment is available and in good repair. Crew members charge radios, fill water tanks, and top off fuel cans.

The burn boss burn permit approval from the dispatcher and checks that weather conditions allow for safe ignition.

Burn Briefing

The burn boss conducts a comprehensive briefing with he fire crew that includes: burn objectives, crew member roles and responsibilities, and response to abnormal and emergency situations. Whenever possible, burn boss conducts a tour of the fire breaks with the crew. This tour ensures everybody is familiar with the fire unit.  Finally, why crew checks their radios to ensure everyone can communicate with one another.

Image of intense head fire.
Roaring head fire on a prescribed burn in dense saw palmettos outside Sarasota, FL.

Ignition

Conducting the prescribed burn is a matter of executing the burn plan. Each team performs its tasks and maintains communication with the burn boss. The burn boss directs burn operations through the assigned crew leaders. Each crew leader directs the activities of crew members. At the point where fire is to commence, the burn boss contacts local dispatcher (9111, sheriff or other designated authority) to inform them of the burn.

Prior to the main burn the burn boss directs lighting a small test fire. The burn boss observes its behavior to ensure wind directions and fire activity is within the parameters specified in the burn plan. The burn boss then gives direction to crew leaders to begin ignition. This typically occurs along the downwind (backing fire) side of the burn unit, proceeding along the inside edge of the burn break. Fire burns freely into the burn unit, however, the crew extinguishes outer edge along the burn break (if it does not go out on its own). Firing continues along the entire downwind side. the crew leader who reaches the end of the downwind side first will hold his or her crew until the other downwind crew reaches its corner.

Building Black

Burning then begins up either flank of the burn unit (flanking fire) in a controlled manner. This ensures good burn coverage inside the unit, while continuously securing the fire break. The crew lead often directs the crew member with the drip torch to light a secondary strip several feet inside the first. The two strips of flanking fire burn together quickly widening the black zone while maintaining low fire intensity. Those extended burn breaks prevent embers from escaping the burn unit. The burn boss takes care, while crews are burn up both flanks to keep them more or less parallel. This prevents fire or smoke from endangering the crew on the opposite flank.

The burn boss dispatches internal ignition crews to ensure fire can safely and completely cover the inner areas of the unit. There are a number of ignition patterns and techniques for internal ignition; each designed to meet specific challenges and burn plan objectives. These interior ignition practices reduce fire intensity and addresses issues of topography and fuel continuity.

Completing the Ring

With with tens or hundreds of feet of black in place, the crew can safely light the upwind (head fire) side of the burn unit. Flame lengths and drifting embers will by that time be wholly unable to breach wide expanse of already burned land. On prairies and savannas where most of the fuel is grass and forbs (wildflowers), the final head fire races inward. The heat generated by this ring of fire creates a might updraft the sucks the fire in on itself. In woodlands the relatively sparse fuel density and bring breaking effect of trees, limits the flame heights. The edges creep inward to consume the remaining fuel.

Image of mop-up at the conclusion of a burn.

Afterwards

As soon as the edges pull in, crews can begin mop-up. Crews use water to put out burning sticks and branches. They stamp out small embers. The burn boss notifies the dispatcher of the completed burn. It usually takes a half hour or less to mop-up grassland and prairie burns. Mop-up can take many hours for woodland burns. The crew must cut open or scrape logs to remove smoldering embers. In these cases mop-up can last overnight or even several days.

More “Good Fire”

Private landowners manage the majority of Wisconsin’s natural heritage lands. Public land managers are not able to keep up with prescribed fire goals on our public lands. Invasive species are degrading our prairies, woodlands and wetlands at an alarming rate. That degradation further reduces habitat for Wisconsin wildlife, contributing to an accelerating loss of songbirds, pollinators, and the invertebrates that form the base of the food chain.

Only ten percent of the fire adapted natural heritage lands in Wisconsin are currently managed with prescribed fire. The potential is there protect those acres that are still in good shape by simply re-introducing fire to the landscape. It is possible to double the number acres burned each year without resorting to more expensive alternatives.

We must first, however, remove barriers to good fire. European settlers ignored the extensive burning practices of native Americans. They failed to understand how burning improved grazing and browsing for game, while helping erosion preventing grasses and native wildflowers protect the soil. As we remove these barriers, we can re-gain the benefits of healthy fire-dependent natural communities.

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