A sprinkling of freezing rain made some paved surfaces slick early Sunday afternoon, but the north wind had yet to turn vicious and temperature remained steady in the 20s -- perfect conditions to fight buckthorn.
"This is our busy season, actually. All winter long, every month," explained Heather Decker, site steward for the 244-acre Wilmot Woods Forest Preserve near Libertyville.
Decker leads the monthly restoration work days at Wilmot, one of the Lake County Forest Preserve District's original acquisitions more than 50 years ago.
One of the most wanted targets for volunteers aiming to remove invasive species is Buckthorn, an aggressive shrub that crowds out native plants. The woody plant, that lines many roadways like tall thickets, is easier to get at when the ground is frozen and other vegetation dormant.
"We cut it flush pretty much and treat the stump. We use an herbicide," Decker said. Volunteers also sowed a seed mix of about a dozen different types of flowers and grasses.
The section of the preserve worked Sunday, adjacent to Libertyville Township's Lindholm Park and shaped like the thumb of an oven mitt, is a dense forest containing many 200-plus year old heritage oak trees as well as hickory, ash, basswood, maple, ironwood, black cherry and elm.
It also is a birders paradise and home to an estimated 400 species of plants and animals.
"It is a high quality site," Decker said. "It's a remnant. There hasn't been a lot of human disturbance taking place in there."
Maintaining and improving that quality is the mission of the restoration work days, which are held monthly throughout the Lake County Forest Preserve system.
As many as three dozen volunteers can show up for a given session but Sunday wasn't one of those days. Accompanying Decker was Kathy Garness, a Forest Park resident and self-described "plant wonk" who serves as the site steward for the Grainger Woods Conservation Preserve near Lincolnshire; Kyle Miller, a sophomore at Lake Forest High School; and Michelle Rodriguez and Yareli Cardenas, friends from Whitney Young High School in Chicago. The students found the activity online for credit toward community service.
Volunteers on Sunday used loppers to cut larger sections of buckthorn into manageable sizes and create piles to be dealt with later by forest preserve personnel.
Decker said removing the buckthorn provides more light that oak seedlings need to germinate.
Garness, a 12-year volunteer, said she learned about the habitat through the Chicago Botanic Garden's 'plants of concern' program.
"I'm not a Lake County resident but I volunteer in Lake County because so many amazing natural areas are here," she said.
"How often do you get a chance to make a difference for nature?"