THE MIGHTY OAK

THE MIGHTY OAK Chicago Region Works to Protect Keystone Species

by Sheryl DeVore

Thriving in Michael and Kendra Eiermann’s Niles backyard is a centuries-old bur oak tree that stands more than 80 feet tall with a diameter of 57 inches and a canopy stretching more than 107 feet.

That the oak is still standing is a testament to folks like the Eiermanns, who along with countless other private residents and public entities, are working to protect not only the many species of oaks native to the Chicago region, but also the ecosystem in which they live. The Eiermanns recently earned a certification of achievement for stewarding their oak tree from the Chicago Region Trees Initiative, headquartered at The Morton Arboretum, in Lisle.

The coalition of organizations works to improve the urban forest where people live, work and play. It also oversees the Oak Ecosystem Recovery Project for the region (Chicagorti.org/OakRecovery). Toni Dati, street superintendent for the village of Niles and municipal director of the Illinois Arborists Association, says, “I played under the Eiermanns’ oak when I was a child. It is a magnificent tree.”

The tree was likely standing before the Europeans settled in the United States. “Back then, oaks were by far the most dominant tree species,” says Lydia Scott, director of the Chicago Region Trees Initiative (crti.org).

Over the past century, the number of oak trees and the acreage of ecosystems in which they thrive have been declining in the region. Lack of sunlight, invasive plants, disease and development have contributed to the decline.

Eight native oak species are common in the Chicago region. These include bur, white and red oak, which grow in harmony with shagbark hickories and other trees where hundreds of other species of plants and animals can thrive (FieldGuides.FieldMuseum.org/sites/default/files/rapid-colorguides-pdfs/500_usa-common_oaks_of_chicago.pdf). “Oaks in our part of the country are considered a keystone species,” says Lisa Haderlein, executive director of The Land Conservancy of McHenry County.

“Normally, people think of a predator like a lion or wolf as a keystone species,” Haderlein says. “We don’t have those. But we do have these amazing trees that support a wide diversity of other plants and animals.”

Birds, insects, salamanders, frogs, butterflies, bats and even the fungi beneath the soil co-evolved with the oaks and are all tied to one ecosystem. “By helping oaks, you help a whole suite of other species,” Scott says.

The Oak Ecosystem Recovery Project was established in 2015 after surveys of the Chicago region showed that only 17 percent of the original oak ecosystems were left. As trees grow old, saplings that sprout from seeds, like acorns, grow and replace the old ones. “But oak trees are not regenerating,” Scott says. “Oaks need light as young plants to grow, and the sun isn’t reaching them because they are living in a very dense canopy.” Hundreds of years ago, Native Americans managed the forest with fire, creating a more open canopy.

Maples and non-native buckthorn are part of the problem. “Young maples don’t need as much light to grow, so they outcompete the oaks,” Scott explains. Buckthorn, introduced from Europe, “creates a dense thicket and takes away the sunlight needed by young oak saplings. It also creates a chemical in the soil that makes it inhospitable for young oaks to grow. Buckthorn provides berries, which birds eat, but it’s not healthy food. It’s low in fat and nutrients.”

Health food for birds is the caterpillars that with private landowners on caring for oak hide in the corky bark of oaks. ecosystems. They learn to replace buckthorn

Oak trees also are contending with with native species and how fertilizers and diseases such as wilt, which particularly pesticides impact the ecosystem, not just affects red oaks and came from Mexico or their property. South America perhaps a century ago. A “We asked each county to identify newer and slower-spreading disease, bur one priority oak ecosystem where they are oak blight, is caused by a native fungus, and working to help engage private landowners,” is being watched by local arborists and land Scott says. “Each of them has undertaken a managers. The main task now for forest An acorn and bur oak tree leaves. range of activities and outreach.” The Land preserve and conservation districts in the Conservancy of McHenry County, for exregion is to remove buckthorn and open up ample, has created the 5,000 Acre Challenge the canopy in the oak ecosystems they manage. (5000Acres.com). “In McHenry County, we have about 5 percent

“For example, the Lake County Forest Preserve is creating of the oak woodland areas remaining that would have been here canopy gaps,” Scott says. “They are carefully selecting trees for historically, and 85 percent of that is on private property,” says removal to provide light for young oaks. Age diversity is importExecutive Director Lisa Haderlein. ant in healthy woodlands so that there are new trees coming up to The challenge becomes to encourage oak woods owned by prireplace those on decline. Oaks grow in light gaps, and increased age vate landowners to join the effort to save and protect them, bringing diversity of oaks is really important.” the total acreage of managed oak woodlands to 5,000 acres.

Work being done on public and private lands to help the oaks Since the challenge began in January, McHenry County now is showing early signs of success. In the Lake County Forest Prehas more than 4,100 acres of oak woods being cared for by private serves and The Morton Arboretum, the smaller oaks are starting landowners and public entities. Private landowners recently comto grow and birds such as red-headed woodpeckers that need open mitted to maintaining more than 300 acres of oak woods, and the oak woods in which to breed are increasing in numbers. Conservancy is working with the village of Bull Valley, a community of 1,100 people and nearly 1,500 acres of oaks, to inform residents about the challenge. “When 5,000 acres is reached, we’ll raise Private Landowners the bar. We want to get to 18,000,” Haderlein Contribute says. The nonprofit also owns and manages “But 70 percent of all the existing oak ecoroughly 600 acres in McHenry County, many system in northern Illinois and southeastern of which contain oak ecosystems. Wolf Oak Wisconsin are on private lands,” Scott says. Woods demonstrates what landowners can So the recovery project works to not only do to enhance these ecosystems. “Wolf Oak enhance oak ecosystems on public lands, Woods is named in honor of one of the most but also to improve those held privately. amazing bur oaks in the area,” Haderlein “People’s yards connect to natural areas,” says. “It’s at least 350 years old. The branches Scott says. “The key is to provide information to private landowners about practices they can undertake to improve ecosystem A bur oak tree at Wolf Oak Woods in McHenry County is more than 350 years old. come down to the ground. It’s spectacular.” Since its acquisition in 2016, volunteers have worked there to open up the health on their properties.” woods, which have attracted The Oak Ecosystem Recovery Project is working with municipalities near the 14,000-acre Cook County Palos Preserves to Celebrate Oaktober October is Oak Awareness Month in Illinois. Here are some ways to celebrate and help the region’s oak ecosystems. red-headed woodpeckers to nest. “This spring, there was a blanket of wild geraniums beneath the oaks,” Haderlein says. enhance private oak woodlands. n Clear non-native shrubs such as buckthorn and “We didn’t plant the geraniums. “One of the challenges that the Amur honeysuckle to let the sun shine in. They were just there waiting for forest preserves have is that while they’re battling buckthorn on their property, the people who live nearby don’t know it’s a n Plant oaks in sunny areas. Take advantage of plant sales and giveaways. For example, the Conservation Foundation, recently gave 50,000 free oak trees to Cook County residents. the sunlight.” Sheryl DeVore has written six books on science, health problem,” Scott says. A recent U.S. Forest Service grant is providing funding n Volunteer to plant and care for oak trees and eco systems at local nature preserves. and nature. She also writes nature, health and environment stories for national and regional for forest preserves and land n Learn more at Chicagorti.org/OakResources. publications. Connect at Sheryltrust organizations to work DeVoreWriter@gmail.com.