The persistent cold and rainy weather has delayed the controlled field burnings that occur each spring in Lake County, officials have said, narrowing the time frame in which forestry workers can complete the crucial ecological tasks.
Leslie Berns, an ecologist at the Lake County Forest Preserve, said the burns would likely be postponed for at least another week. That means they'll start about three weeks later than usual, she added.
The late start may force the forest preserve to skip some of its scheduled burns this season, she said. Berns said they stop as soon as animals and green vegetation reappear.
"We'll burn until conditions dictate that it's no longer wise to burn," she said. "A lot of it is dictated by soil temperatures and when critters start moving around. If they start moving around early, then we stop."
The forest preserve, local municipalities and private landowners burn thousands of acres every spring and fall in Lake County, in what experts say is a Native American tradition established long ago.
Steve Barg, executive director of Conserve Lake County, said the fires help maintain a healthy and diverse ecosystem in the county's natural areas. They work by eradicating invasive plants, including buckthorn and honeysuckle, plants that could otherwise push out native species, he said.
Seasonal burns also strengthen native plants and help them produce more seeds, Barg added. The fire extends their growing season while recycling nutrients back into the soil.
"It's probably the most cost-effective land management tool," Barg said. "It's a great way to manage healthy, natural ecosystems."
The forest preserve had planned to burn about one-tenth of the more than 30,000 acres in wetlands, prairies and woodlands it maintains across Lake County, officials said. Despite the uncooperative weather, Berns said the agency could still get to 1,500 to 2,000 acres this spring.
Berns said the ideal window for controlled burns would have been early March through the end of April. Rarely do weather conditions allow them to continue into May.
The longest the forest preserve has waited to do its first spring burn during the last 15 years was in 1999, according to data from the agency. That year it didn't light its first fire until March 22.
An unseasonably warm, dry winter last year allowed the agency to do its first burn Jan. 6. It did its last one March 29, after burning more than 1,400 acres.
Libertyville Township and Lake Forest are among the many municipalities in Lake County that perform seasonal burns of their own.
Chuck Myers, Lake Forest's superintendent of parks and forestry, said the city planned to burn up to 50 acres, including a few bluffs at Forest Park.
Meanwhile, Libertyville Township plans to burn around 100 acres, said field manager Chris Slago. The township oversees burns at Oak Openings and Liberty Prairie, two nearby state nature preserves.