Two agencies responsible for maintaining Chicago’s natural areas are creatively reinventing the uses of invasive tree species and native trees infected with invasive insect species.
the Cook County Forest Preserve The Woodworking with Invasive Species program gives volunteers the opportunity to cut down invasive buckthorns and carve them into works of art or useful tools, such as walking sticks.
“When you start cutting it, right away it’s pretty soft,” said Tim Mondl, Cook County Forest Preserve program coordinator. “We only use fresh produce in our programs. The longer you let it dry, the harder the wood becomes.
European buckthorn is a type of non-native small tree originally introduced to North America in the 1800s as an ornamental plant. Since then, the invasive species – the sale of which is illegal in Illinois – has threatened the biodiversity of the Chicago area: European buckthorn accounts for 36% of all trees in the seven-county region surrounding Chicago, according to a 2020 Chicago Area Tree Census by Morton Arboretum.
Cook County Forest Preserve wildlife specialist Kim Kalosky said buckthorn stunts the growth of other plants, trees and grasses, preventing native species like young oaks from thriving.
“It grows in very dense thickets and it tolerates shade very well,” Kalosky said. “So often we have a thicket of buckthorn and there’s either completely bare ground underneath because it’s shaded from all the rest of the growth, or only the buckthorn seedlings can tolerate that density of shadow.”
Kalosky said the Cook County Forest Preserve has eliminated 5,000 acres of invasive woody shrubs since joining the agency eight years ago.
Across Chicago parks, artists have sculpted 41 dead trees into different works of art as part of the Chicago Tree Project, a partnership between the Chicago Park District and the nonprofit organization Chicago Sculptures International. The program began in 2014 when thousands of ash trees were dying from the emerald ash borer infection.
The larvae of the invasive insect, which was first discovered in Michigan in 2002, passed through the vascular system of ash trees, killing them within a few years. The estimated number of standing ash trees in the Chicago area has declined by 46%, according to the 2020 Tree Census.
In 2017, Janet Austin president of Chicago Sculptures International, sculpted a dead ash tree in Palmer Square Park with drawings representing the maze-like paths that the emerald ash borer larvae create under the bark.
“I think by allowing coins to live in the world a little longer, they’re still providing nutrients in the soil, places for animals,” Austin said. “They emphasize the fact that these trees are changing and that they will at least be a work of art for the next few years.”
A Cook County Forest Preserve representative said the agency is planning its next “Woodworking with Invasive Species” event for July 21 at 5 p.m. at Rolling Knolls Forest Preserve in Elgin, Illinois. .