Prescribed burn management is utilized in Chicago Park District Nature Areas to achieve several objectives:
- Reduce the spread of weeds and undesirable woody vegetation
- Promote the growth of native plants
- Enrich and return nutrients back to the soil by burning off dead vegetation on the ground
- Encourage plant germination by allowing sunlight to warm the dark soil. This management technique is used widely by land managers throughout the Midwest and the country by federal, state and local municipalities. Without fire, nature areas are likely to become thickets of shrubs or weeds with little variety of plant and animal life.
The Chicago Park District notifies neighborhood groups, city officials and park councils at least two weeks prior to the burn season if a burn is planned in their district. In addition, signs are posted at the nature area entrances prior to the burn. On the day of the burn, the Park District notifies the fire departments and city officials. Fire departments are called at the beginning and end of each burn.
The Chicago Park District Department of Natural Resources carefully assesses the needs of each nature area to determine the management needs of that site. Once the Illinois Department of Natural Resources and the City of Chicago grant a permit to the Chicago Park District to carry out the prescribed burns, a professional prescribed burn manager prepares a burn prescription plan specific to each individual site. The burn plan includes areas targeted for the burn, ignition patterns, and the location of firebreaks. A firebreak is anything, such as a road, a mowed path, or a burned strip of land, which will stop a fire and contain it to a controlled area. The burn plan also specifies ideal weather conditions, number of staff, and type of equipment needed and the ecological goals of the burn. Only professional, well-equipped, fully trained burn crews carry out the prescribed burns under the supervision of the prescribed burn manager. On the day of the burn, the crews carry cell phones and two-way radios. Ample portable water tanks and a water truck are also present the day of the burn.
Fire does not harm native herbaceous plants because their root systems extend far into the ground – often more than twice the length of their foliage above ground. Native grasses have buds that are located beneath the soil surface, where they are not harmed by the flames. Some trees such as oaks and hickories grow a thick bark that protects them from fire. Animals stay safe by retreating to burrows, flying away or simply moving to another area. Burns are also scheduled to occur before spring bird nesting occurs.
Prescribed burns temporarily produce some air pollutants; however, a healthy native ecosystem adapted to fire will remove more carbon dioxide and produce more oxygen in the years following the burn because the vegetation becomes fuller and more productive. To put in perspective, fewer emissions are produced from a prescribed burn than are produced from frequently mowing a comparable area of turf grass.
Burns are conducted in the early spring and late fall. To ensure safety and to minimize smoke emission, trained crews carefully time the burn for a specific range of temperature, wind direction, wind strength, humidity, barometric pressure, and ground moisture conditions. The exact date and time is subject to change depending on whether or not optimal conditions for a safe yet effective burn are available.
Recently burned areas initially have blackened earth, but the sites green up very quickly in the spring. The season following a controlled burn the vegetation is lusher, the flowers are more radiant, and seed production is more plentiful.
All burns in Chicago Park District nature areas are conducted by professional, licensed contractors. Nature stewards will be notified when a prescribed burn is scheduled for their site. Stewards are welcome to attend and observe the burns as well as assist the Chicago Park District in notifying and educating the surrounding community about prescribed burning.