Contemporary biologists recognize that prescribed burning is an important management tool that mimics wildfires. Our native prairies and woodlands have adapted to and become dependent upon fire over millennia. Burning helps keep non-native and some native plant species that aren’t adapted to fire in check to promote balance and greater biodiversity. Natural areas without periodic fire can quickly become choked with invasive trees, shrubs, and herbaceous plants such as buckthorn and honeysuckle.

The suppression of overabundant woody vegetation and invasive species by prescribed fire has allowed vast acreages of tall- and shortgrass prairies and savannas in the Midwest to flourish. Decreased fuel loads also help reduce the potential for and intensity of wildfires.

Following a prescribed burn, many native plants are more robust and produce more seeds. Fire lengthens their growing season, recycles nutrients and, for a few species, is critical for their seeds to germinate.

For more information regarding prescribed fire on the Illinois landscape, visit the Illinois Prescribed Fire Council website.

Prescribed burning involves identifying the area to be burned (the “burn unit”), establishing control lines to prevent the fire from extending into unintended areas, and intentionally setting the burn unit on fire using a variety of techniques.

To maximize the health of the natural communities, areas within the Forest Preserves are managed through our prescribed burn program. Fire is an important ecological process that has shaped the composition and structure of the ecosystem, and the maintenance or restoration of various community types cannot be achieved without its use.

Prioritized areas receive intensive ecological restoration efforts, like brush removal and invasive species management. Prescribed burning is part of this process to heal and maintain a balance that will stabilize and promote the biodiversity of native species within these areas. Learn more about natural areas restoration.

Fire can also be an important tool to attain specific maintenance objectives such as controlling invasive trees and shrubs and preventing them from returning once major restoration has been completed. This in turn supports the long-term sustainability and health of our remnant oak/hickory forests and savannas.

A typical burn season may only consist of five to ten days where weather conditions are adequate or within parameters. When planning and implementing a prescribed burn, we consider soil moisture, wind speed, wind direction, smoke dispersion, fuel load, temperature and relative humidity, as well as the management needs of the particular habitat. These elements influence flame height, rate of spread, how smoke will dissipate, and overall potential to meet the burn objectives.

Prescribed burning requires extensive planning, training and execution by certified personnel. Our equipment is modern and well-maintained, and our safety track record is exceptional. As a result, the Forest Preserves of Cook County has one of the largest and most successful urban prescribed burn programs in the country.

Prior to burn season, the Forest Preserves Department of Resource Management obtains all necessary permits from state and regional authorities. To ensure public safety, we start each morning by informing local agencies where we plan to burn, including municipal fire and police departments, dispatch centers and Forest Preserves Police. We also communicate with nearby neighbors, Cook County commissioners, the Illinois Environmental Protection Agency and the Cook County Department of Environment and Sustainability.

All participants who are on the ground for our prescribed burns have received specialized training and certification, which involves learning fire behavior, methods of ignition and suppression, proper use of equipment, and more. The burn boss and fire crew leaders also have extensive training in modeling smoke and fire behavior to better understand expected and observed conditions.

Prescribed burns in the Forest Preserves of Cook County are conducted within a specific seasonal window, from mid-October to mid-April, aligning with the dormancy of vegetation and wildlife. To minimize ecological impact, these burns are split into spring and fall sessions, as they require precise conditions such as dormant wildlife and vegetation. Burning outside the growing season results in drier ground vegetation and less smoke output. Additionally, specific sites susceptible to erosion are burned in the spring to reduce the time the soil is left bare and prevent erosion issues. This spring-fall division reflects the need for precision in conducting these prescribed burns.

We develop an extensive burn plan for every site that specifies the proper weather conditions to minimize smoke impacts to area residences, businesses, schools and roads. Each plan identifies the limits of the burn unit—bounded by trails, streams and other barriers that help keep the fire contained. The plan also includes potential hazards and safety issues, procedures for ignition, acceptable weather and fuel conditions, personnel and equipment needs, and the management goals and objectives for the burn.

Fire control lines, or burn breaks, are established where needed and may be installed prior to the burn and verified immediately before ignition. If necessary to protect site visitors, access to portions of a preserve may be restricted or the preserve may be closed for the duration of the burn. Crews patrol all fires to ensure that the burn is contained, and smoke is managed in compliance with the Illinois Environmental Protection Agency’s smoke management plan.

Data is recorded during and at the conclusion of each burn, including weather conditions, observed fire behavior, and extent of burn coverage, to help staff evaluate the effectiveness of the fire in achieving site management objectives, as well as safety and operational procedures.

For those unfamiliar with prescribed burning, the aftermath may appear shocking at first. A blackened and smoking landscape greets the eye, which can be reminiscent of wildfire destruction, but the reality is far different.

We carefully plan and time our burns during the spring and fall when conditions allow for fire to minimize harm to wildlife. We aim to ensure reptiles, amphibians and insects are hibernating or overwintering in some capacity, so the burn doesn’t negatively impact them.

Leaving areas of fire resistance adjacent to or within our burn units to allow places for wildlife to flee to is included in our burn plans. Although most insects are underground during prescribed burns, some mortality still occurs, and we prioritize caution in areas with known endangered insect populations. While unfortunate, this can sometimes be beneficial for controlling populations of undesirable species, such as ticks. Unburned areas ensure there are enough insects to accomplish repopulation and the pollination and decomposition needs of the next growing season.

Yes, prescribed burning can be dangerous. Prior to a prescribed burn, variables affecting fires are carefully studied. Our prescribed fire crews are trained to monitor weather and fuel conditions to ensure a safe burn.

Through training and experience, the prescribed burn crews can anticipate issues that may arise and take remedial actions. This has allowed this program to effectively manage our natural lands while maintaining public and burn participant safety for more than 25 years.

We implement our prescribed burn program with the greatest attention paid to the safety of visitors and the general public. An important element of this is smoke management. Common smoke management considerations include excessive smoke on roadways which creates visibility concerns for motorists, and the impact on individuals with health conditions that can be aggravated by smoke such as asthma or allergies. Facilities with important air intake systems like hospitals and schools are also vulnerable.

Our strategies for minimizing impacts resulting from smoke include monitoring weather conditions that influence smoke dispersal, altering ignition strategies, and proper site selection on the day of the burn.

We constantly update our burn plans to identify the location of smoke-sensitive groups. If you or a family member has a health condition that could be triggered or aggravated by smoke or could otherwise be negatively impacted by prescribed burn activities, please contact us so that we can include your information in the appropriate burn plan(s). We will ensure you receive advance notification of planned prescribed burn activities to help you avoid smoke exposure or other impacts.

If you have any questions regarding the Forest Preserves of Cook County Prescribed Burn Program, please reach out to us at resourcemanagement.fpcc@cookcountyil.gov.

The Forest Preserves posts warning and notification signs along roads and trails while conducting burns, and crew members are assigned to monitor trails and smoke output. We may station a mobile unit if there are factors that could contribute to impacting adjacent roadways or off-site smoke-sensitive targets. This can provide live feedback and allow us to adapt to conditions or changes in weather as quickly as possible. We may close off part of a trail if necessary to ensure safety, but this isn’t common.

The public is welcome to watch a prescribed burn from a safe distance, and we’re constantly keeping a lookout for anyone who may be near the burn site.

For crew safety, we start every burn with a pre-burn briefing. This entails going over a map of the burn unit, knowing hazards, reviewing safe zones and escape routes, goals and objectives, and the methods we will use to conduct the burn.

While performing the burn, we adhere to what is called “line of sight.” We never perform burns alone. Crew members are paired with a “burn buddy,” and maintain a “line of sight” throughout the burn and stay in communication with our radios.

A prescribed burn today helps reduce the risk of a wildfire tomorrow. Our region features plant communities that evolved with fire before and with human intervention. Past policies of fire suppression increased the risk and intensity of wildfires because burnable fuels readily accumulated in many areas to dangerous levels. Repeatedly burning these fire-tolerant plant communities in an intentional manner simulates this once-natural process and is one of the most effective ways to help reduce the risk of uncontrolled wildfires that can threaten safety and property.

Forest Preserves senior burn leaders conduct training with local fire departments about our program and advise them on how they can safely respond to wildfires on Forest Preserves properties. Forest Preserves staff have built great relationships with many of the fire departments across Cook County through these trainings, and as a result, these fire departments are better prepared to respond to wildland fire situations.

In the video below, presented by Jay from “Jay’s Chicago” by WTTW, you’ll learn about the techniques used by the Forest Preserves of Cook County to conduct prescribed burns. Discover the essential steps involved in these controlled burns, ensuring the protection and conservation of natural areas.