Conservation Corner

Fire and Grasslands: Made for Each Other!

By Scott Schaeffer, IDNR District Wildlife Biologist

More than perhaps any other natural element, fire was and to a certain extent, still is the most important disturbance in shaping natural landscapes. Many native plants and animals evolved with fire or if they couldn’t, they sought other habitats or disappeared from certain ranges.

Plains animals that made a living in open grasslands in particular relied on periodic fires to maintain and reinvigorate the forage grasses and forbs (i.e. flowering broadleaf plants) they relied on for food and protection or concealment from predators. Fire recycled vital plant nutrients, returning them to the soil. Old plant residue is removed, thereby opening the sod’s canopy and allowing sunlight to the new emerging bud in the spring. Repeated fires kept the ever-advancing woodlands at bay, and in many places, woodlands were confined to north facing, cooler slopes and floodplains along major rivers. Glaciated portions of Illinois, most of the northern two-thirds of the state, contain some of the richest soils in the world and were once part of the Midwest tall grass prairie that ranged from the central Canadian provinces all the way south to parts of Oklahoma. The prairie sod that was here for centuries added soil tilth, organic matter, and depth to the soil profile. Midwest farmers, in particular, should be thankful for prairie vegetation.

Today, the use of fire habitat management is better understood as fire behavior has been researched and experimented with. Further, tools useful in managing fire such as drip torches, flappers, fire rakes, pressured water tank, and backpack sprayers, etc. are readily available to smaller land managers. Planning a controlled burn, called a prescribed burn, begins with identifying the goals or anticipated results of the burn, identifying potential hazards such as buildings, roads, power lines, etc., desired wind direction and speed for smoke control, necessary manpower and equipment, and most importantly, firebreaks.

Firebreaks can render a prescription burn almost boring and furnish an important safety net in the event that a fire escapes. Firebreaks must cover the entire perimeter and can be natural features like streams and other bodies of open water or man-made features such as grazed pastures or tilled croplands. Most firebreaks are installed in advance of the controlled burn. Strips that serve as good firebreaks are those whose widths are generally two and a half times the height of the vegetation your burning, are either worked up to expose bare soil, or closely mowed the previous growing season. At this point, fire managers use the prevailing wind direction and light the backfire against the wind. Eventually, they may or may not decide to light a headfire, which burns with the wind and much faster. The two fire lines will remove all the available fuel and extinguish themselves. The local fire department must be notified prior to ignition, and many fire managers will erect signs along adjacent roadways to alert motorists of the controlled burn.

In the interest of ground nesting birds and other wildlife, managers avoid burning entire fields in a given spring. Pheasants, for example, prefer 19 inches of standing vegetation and 60% ground residue for nesting. In most cases, fields burned in the spring will be avoided by nesting wildlife. However, the open ground layer and increased seed production from flowering plants will attract ground-foraging wildlife later on. Most grasslands in northern Illinois are burned on a three year rotation, with about one-third of the acreage being burned each spring.

From about mid-March through mid-April, make certain that the smoke you see isn’t part of a controlled burn before you call 911. Volunteers from Pheasants Forever, biologists, farmers, and other land managers will be out burning grasslands. If you would like to learn more about this topic or how to conduct a controlled burn, please call Illinois Dept. of Natural Resources Wildlife Biologist, Scott Schaeffer at (815) 273-2733.