Prescribed burning at Fermilab

As you commute to and from the lab in spring and fall, you may notice Roads and Grounds crews conducting prescribed burns in the natural areas. It may bring several questions to mind, such as what is a prescribed burn, why are prescribed burns conducted, and why only in spring and fall?

Illinois ecosystems are fire-adapted ecosystems that evolved with frequent fires on the landscape. In prairies, fire helps to stimulate root growth in many plant species. Prescribed burns also give the ecology crew a clean slate to better manage invasive species, such as crown vetch and bird’s foot trefoil that lower biodiversity. In woodlands, our native trees have thick bark, and healthy individuals withstand the effects of fire while smaller, invasive brush species can be set back or killed by repeated fire. A prescribed burn is one of the most effective methods of restoring and maintaining natural ecosystems, one that takes considerable time to plan and carry out.

The weather, crew size and seasonal variables all contribute to determining when Roads and Grounds conducts prescribed burns at Fermilab. Photo: Wally Levernier

A prescribed burn is an event that is planned based on many weather, crew size and seasonality variables. Prescribed burns start in the fall when vegetation has cured and dormant for the winter. They occur through winter until snow falls or it is too cold, and they resume in spring until around April 15. This end date varies year to year, based on when wildlife and plants become more active.

In order to have a well-performed prescribed burn, weather forecasts are closely monitored to find a narrow set of conditions for each individual natural area to allow for safe execution of a prescribed burn while minimizing chances of impacts to the lab. Having sufficient crew size also determines what areas can be burned on a specific date. Once an area is selected, pre- and post-burn meetings are conducted in order to make sure that everyone understands the plan. Notifications are made to the fire department, security, control room and other relevant individuals (central facility managers, building managers, etc.).

Once the prescribed burn is completed, the crew cleans up the borders of the burn unit. Sometimes when woodlands are burned, some woody material may be smoldering. The crew makes sure that   there is no chance of fire escaping. Burning is part of the natural process, otherwise, dead and dying material may accumulate faster than it can decompose, creating a barrier at the woodland floor that will reduce native plant diversity.

The prescribed burn process is one element of creating and trying to maintain a healthy ecosystem at the lab to promote both plant and animal diversity.