As a management tool, controlled burning provides several benefits to our natural systems within the Park. The use of controlled burning is much more effective, less time consuming, and more environmentally conscious than other forms of vegetation management activities such as herbicide applications or mowing. The use of fire helps conserve resources by reducing the amount of time and money required to meet management goals. Controlled fire also benefits the natural system by converting dead and dying vegetation into usable energy and nutrients for the soil and living organisms in that habitat. Much of the dead and dying vegetation would take years, if not decades, to decompose and return back to soil nutrients. The quick removal of all the dead and dying vegetation provides increased sunlight and warmer temperatures at the ground level for newly emerging native seedlings in the spring. Furthermore, controlled burns have been shown to decrease the invasive plant species in the area, creating a clean and nutrient rich site for native plants to thrive.
The best way to think of controlled fires is to compare them to a medical prescription for ailing habitats. Depending on what type of habitat being considered and what symptoms are affecting it, a maintenance technique is prescribed. This is similar to getting a prescription from your doctor depending on what ailments and symptoms are unique to you. Different burning techniques, timing and intensities are all considered when developing the prescription and that prescription is implemented with a specific end-goal in mind. If you are trying to rid your body of an infection, the prescription is for antibiotics, once a day for 10 days. Similarly, if you are trying to rid a prairie of woody encroachment, the prescription might call for frequent (every 1 to 3 years) and hot (high intensity) fires for a span of 15 years. Also, as with any prescription, monitoring is required to be sure the treatment is a success. If treatments are not successful, or symptoms change, the prescription will need to be adapted to meet the new circumstances.
Controlled burns within the Park are always conducted by trained professionals with many years of experience using fire as a management tool and with the permission of the City of St. Louis. In order to successfully and safely use fire as a management tool, several weather conditions and other criteria must be met. Relative humidity, wind speed and direction, temperature, and recent precipitation play a large role in fire behavior and these parameters must be within acceptable ranges prior to setting a controlled fire. Prior to every burn, every effort is made to protect sensitive trees, utility boxes, or other structures within the proposed burn area. Trees and other structures are protected by mowing and removing all the dead and dried vegetation (fuel) from around the base. Certain lighting techniques, such as backburning and strip burning are also employed to maintain constant control of prescribed fires.