Controlled burns aim to revitalize prairie grass

Rhys Saunders

Interstate drivers probably have noticed burning fields and ditches along the highways in recent weeks.

But it’s nothing to worry about.

The Illinois Department of Transportation began burning prairie grass along interstate highways in February in an effort to regenerate desirable species.

The burns, conducted every two or three years, are expected to continue until the end of March, according to Illinois Department of Transportation spokeswoman Paris Ervin.

“Right now we are concentrating on (Interstate) 72 east of Springfield and also (Interstate) 55 from Springfield to Lincoln and 55 northbound near Litchfield,” she said. 

IDOT officials notify fire departments in towns neighboring the burned areas when officials deem it necessary, she said. However, workers also have a truck filled with 1,000 gallons of water on hand for the rare cases in which fires get out of control.

“We do a good job of keeping the fire under control,” Ervin said.

Chatham Fire Chief Philip Schumer said IDOT does not notify his department about such burns, although his firefighters have never had to respond to a state-authorized controlled burn.

“We do have some farmers in the area that burn off their prairie grass, and they’re pretty good about calling us,” he said.

Williamsville Fire Chief Keith Hamrick said his department also is not contacted by IDOT about its burns. He added that state crews typically keep their fires well under control.

Without burning, natural selection takes over, and untended areas often become forests. Burning also delays the growth periods for cool-season grasses, which spring up earlier than warm-season grasses. That gives the warm-season grasses a chance to sprout, said Aaron Kuehl, director of conservation for the local branch of the conservation group Pheasants Forever.

“The warm-season grasses lay dormant a little bit longer before they start putting on their active growth,” he said. “They’re more suited to drier conditions.”

Timing is important because burning warms the soil and allows the sun to directly penetrate the ground, Kuehl said. Although there are many reasons to conduct controlled burns, the most important is to reduce encroachment by exotic grasses and woods.

“The burning act itself removes the litter, warms the soil and frees up nitrogen and other nutrients for the grasses,” he said.  “It actually frees up the nutrients that are held in the dead vegetation.”

Burning is better than mowing because it increases the diversity in vegetation species. Burning also improves wildlife nesting habitat by creating “skips,” areas that are not as affected by fire as the fully charred ground.

“For example, a clump behind a fallen branch, or maybe a divot where some water was standing,” Kuehl said. “You may get different treatment that may favor a different species. If you’re burning during a nesting period, these birds are going to re-nest in adjacent areas.”

“Pheasants and ducks actually like green vegetation around them when they’re nesting, versus the tall switchgrass. By having more species, you get additional insects that are good for the chicks.”

Rhys Saunders can be reached at (217) 788-1521