ParkTalk Blog – The Science of Prescribed Burns

Tuesday, September 30, 2025

Prescribed burns are intentionally ignited and controlled fires utilized by park districts and conservation groups to maintain and improve various natural areas. While it seems counterintuitive to use fire to improve an ecosystem, there are several significant benefits to burning. During the spring and fall seasons, the Naperville Park District utilizes this practice in their parks and natural prairies to help enhance their overall environmental health. While one of the more crucial benefits of prescribed fires is burning plant debris and reducing the risk and severity of potential wildfires, they also provide numerous soil and biodiversity benefits that create a better overall environment.

Biodiversity: Burn and Let it Thrive

Fire plays an important role in the lifecycle of many wildlife species. After living with periodic fires for thousands of years, certain Midwest species of plants have evolved to rely on regular fires to thrive or survive. Over time, certain native wildflowers and grasses have developed root systems which extend 15 feet or more into the soil allowing them to survive fires and resprout from their roots. Additionally, the effectiveness prescribed fires have for removing invasive species allow native plants to grow. For example, white oak saplings, like many other oak species, thrive after prescribed burns due to the reduction of invasive species and increased exposure to sunlight.

Foliage isn’t the only natural aspect that relies on prescribed burns. Cleared natural areas allow animals such as rabbits and ground-feeding songbirds to travel, access food and mate. “Burn bosses” (which is another way of saying, “trained and certified professionals”) take into consideration how wildlife will be affected by prescribed burns. Every fire is planned to minimize disturbance and keep wildlife safe so they may enjoy the benefits of their ecosystem. Once new wildflowers emerge, pollinators, such as bees and hummingbirds, transfer pollen between flowers, which is an essential part of the reproduction of plants. Prescribed burns play a delicate role in environmental health and in turn make our ecosystem more diverse.

Nutrition for the Soil

Fire is both a natural disturbance and a rejuvenator. As plant debris and invasive plants burn, the nutrients tied up in the vegetation break down into ash and char and are fed back into the soil. Plant ash can be a good soil amendment in small quantities because it is rich in nutrients. This is why wood ash from a fireplace is commonly considered a good fertilizer like compost or mulch. The nutrients from the ash are absorbed into the soil and assist in regrowing lush plants that keep the natural area healthy in the long term. There are a variety of nutrients that are needed by plants for growth, and the role they play can be complex.

There are various nutrients needed for plant growth including primary macronutrients, secondary macronutrients, and trace elements. The three primary macronutrients are nitrogen, phosphorus, and potassium. Nitrogen is essential to life and is a key element found in all plant cells, plant proteins and hormones, and in chlorophyll. Phosphorus helps transfer energy from sunlight to plants and stimulates early root and plant growth. All manures contain phosphorus, and potassium is a natural disease resistance for plants and can improve overall plant quality. Secondary macronutrients include calcium, magnesium and sulfur. Trace elements are essential to plants and soil, but only in small amounts. Trace elements include iron, manganese, zinc, copper, boron and molybdenum. All of these elements play an important role in producing healthy vegetation. 

These nutrients are often found in understory, or the layers of vegetation on the ground. It often takes years for this material to degrade and become viable to soil. However, prescribed burns accelerate the time needed to break down plants and dead materials. It is important to note that prescribed burns must be done in a specific manner by trained professionals. Depending on the intensity and frequency, fire can make the soil too hot and cause excessive nutrient loss through erosion, oxidation, volatilization or leaching. To avoid this adverse effect, the Naperville Park District and other practicing agencies require staff to complete a thorough training and certification process, so they are best equipped to properly practice prescribed burns.

Prescribed burns are viewed as one of the most effective ways to maintain prairies, wetlands and woodlands. Not only do they provide safety benefits by removing dry plant debris, but they have ecological benefits that improve the qualities of the landscape and wildlife. The Naperville Park District uses prescribed burns as an effective tool to clear out invasive plants that harm the natural area and give vital nutrients to the soil that help native plants grow. The District updates their burning schedule each spring and fall season at www.napervilleparks.org/prescribedburns.