Winter freeze aids forest preserves' fight against invasive species

Frozen ground lets workers take heavy equipment to more remote areas

By Matthew Walberg, Chicago Tribune reporter

6:26 p.m. CST, December 26, 2013

See original story at: http://www.chicagotribune.com/news/local/ct-invasive-species-winter-met-20131226,0,876242.story

The bitter cold that has enveloped the Chicago area might not be everyone's favorite, but it's perfect weather for those who continue the fight against a host of invasive plants during the winter months.


"This kind of freeze we're getting right now is what we dream about during the summer," said Chip O'Leary, the resource ecologist for the Cook County Forest Preserve District. "A lot of that work we do ... requires frozen conditions so we can get heavy equipment out without damaging the soil."

Atop the agency's most-wanted list are larger trees and shrubs such as buckthorn, honeysuckle and multiflora rose. The three are some of the worst offenders in a rogue's gallery of non-native plants that have overrun vast tracts of the district's property.

The invaders choke out native plants, including those that provide food for wildlife, turning the land into "green deserts."

Watchdog organizations that once accused the district of paying more attention to politics and patronage hiring than to maintaining the agency's properties now applaud the renewed focus on reclaiming the land from tenacious invasive species. These bad boys of the plant world have overrun more than two-thirds of the district's 106 square miles of land, officials said.

Benjamin Cox heads of one of the most prominent watchdog organizations, Friends of the Forest Preserves. Much of the eradication work, he said, is carried out by volunteers, adding that the district is far more involved than it once was. He said officials are much better at marshaling volunteers or hiring contractors.

Work crews spend much of the spring and summer removing unwanted plants and reseeding areas with native species. The winter deep freeze allows workers to trek into more remote areas with large chippers and other equipment to clear infested areas, O'Leary said.

"I think in a lot of ways it's easier during the winter," he said. "Any animals that might use that stuff are pretty much dormant. The snakes are underground and the birds have flown south. ... And you also don't have annoying things like mosquitoes or bees or poison ivy."

Cox said he also prefers volunteering during the winter.

"You just dress warmly, and pretty soon you find yourself stripping off layers," he said. "And we usually build a fire, since that's the most efficient way to get rid of this stuff once it's cut down. People like that — it's nice to be around."