Restoring Cranberry Slough to glory
Ecologists thought it had been lost forever.
But just one year into the Cook County Forest Preserve District’s 2015 natural and cultural resources master plan, the tiny twayblade orchid re-emerged at Cranberry Slough in the Palos Preserves.
“We thought itwas extricated from this site,” said Kristin Pink, resource ecologist for the Forest Preserve District. “But the very first season after brush removal we found it again.”
The tiny ground-dwelling native plant with purple flowers was justwaiting in the soil for someone to clear away dense invasive species so sunlight could reach it, she said.
The ongoing work at Cranberry Slough, so named because it is home to a bog that once bore the large cranberry plant, has all the makings of a classic tale of good versus evil, with the battle being waged before the eyes of casual observers.
It is the story of a land once flourishing with native plants and animals that over decades of neglect became overrun by invaders. Seeds from plants such as the bush honeysuckle, brought over from western Asia and embraced by Chicago-area homeowners because of its beautiful flowers and scent, were transported by birds to the forest areas.
Though lovely, Pink said, the
bush does not belong in northern Illinois, and its presence is harmfully affecting everything from plant life to bird health to forest aesthetics. Like other invasive plants, the honeysuckle is aggressive and quickly expands its reach, snuffing out native flora.
On a recent rainy Tuesday morning, Pink, who grew up on the Palos Preserves border in Willow Springs and graduated from Argo Community High School and the University of Illinois, took me and a photographer on a 2.3-mile tour of the Cranberry Slough area.
As we traversed the multiuse Country Lane Road, partly in truck, partly on foot, we could easily point out the areas where restoration work already has been done.
On one side of the trail, the woods were dark, dense and overgrown with nonnative plants; onthe other, rain and sunlight made its way to the ground, nourishing native jewelweed and buttonbush along theway.
The restored area is healthier for plants and animals, better for water quality and more inviting to the hikers and horseback riders who use the trail, Pink said.
The 12,000-acre Palos region is a top priority in the Forest Preserve District’s master plan, Pink said. And Cranberry Slough, home to the only bog in Cook County, is a top priority among that, she said. Other areas targeted for ecological restoration are Sand Ridge in South Holland, Jurgensen Woods in Lansing, Busse Woods in Elk Grove Village and Deer Grove in Palatine.
Cranberry Slough, west of LaGrange Road on 95th Street, sits in a northeast section of the Palos region, which is the largest tract of forest preserves and most contiguous natural area in the county, Pink said.
The slough is “big and mostly a remnant natural area — an ecological community that’s mostly intact,” she said.
A remnant area is one that is near to its native roots, she explained. The soil has never been turned for farming, the tree canopy is largely intact and there’s been relatively little degradation, she said.
“The plants and animals that live here have essentially lived here for thousands of years,” Pink said. The area represents “a direct line all the way back to the glaciers” some 12,000 years ago.
In the three years since the county began work to remove invasive species there, 220 acres of the 570acre site have been cleared, mostly with grinding machinery and prescribed burns, which rids the area of leaf litter and stimulates the native system of plants, Pink said.
And the difference has been significant, she said.
Already, more native plants are flourishing, and that bodes well for the wildlife, she said. Officials hope the change will benefit the federally threatened northern long-eared bat that has been spotted there, aswell as two wood peckers, the red-headed and the pilliated, both of which are rarely seen across other parts of the county but appear frequently near Cranberry Slough, she said.
Indeed, during a twohour tour, a red-headed woodpecker was spied flitting among the trees. Near Crooked Creek, a pair of hummingbirds chased each other among the jewel weed. Andthe calls of many different birds were heard, including the Eastern WoodPeewee, named for its song.
So far the Forest Preserve District has invested $460,000 of the $800,000 it expects to spend, said spokeswoman Stacina Stagner, with work being done by forest preserve employees aswell as contractors.
“We still have a lot to do, but we’re moving at a brisk pace,” Pink said.
In November, prescribed burning once again will get underway.
“Sometimes when people hear ‘fire,’ they might think of wildfires in California. It’s much different here,” she said.
The intentionally set fires that the Forest Preserve District conducts are lowintensity, designed to burn off debris, Pink said.
“When you remove leaf litter, in the springtime that black soil left behind will heat up faster, and you’ll have plants greening up quicker. You’re also going to have more flowers on the plants. The plants become more productive. And that means more food for the entire system. So you’ll have more insects. It’s quite a remarkable tool,” she said.
Cranberry Slough also is home to several wetlands, which benefit as well when invasive species are removed, Pink said. The fishless ponds are home to frogs and salamanders that head upland to forage. If the land around awetland is covered with nonnative shrubs, the amphibians can’t find enough food, she said.
“It’s a complex system, all intertwined,” she said.
Because the area has the ability to return to its native state, it was given top pri- ority, Pink said.
Cook County is among the most ecologically diverse areas in the country, Pink said. Everything that is living atCranberry Slough is “the zenith of genetic and biotic diversity,” Pink said. “That just cannot be replaced. It cannot be planted. We just don’t understand enough. We must focus on (restoring) remnants. Cranberry Slough is mostly a remnant. It just needs a little bit of help. That’swhywe’re focusing here and are expanding outward to restore 12,000 acres in the Palos area.”
“It’s an ambitious project, but we are making great progress,” she said.
The work of returning the area to its bright, sunlight-dappled native state will be bolstered by sustained land management, aimed at keeping the area as it was meant to be, she said. Because of this work, other rare native plant species, including the Michigan lily, Indian tobacco and fire pink, are returning to the landscape.
All of them, including the purple twayblade, are harbingers of evenbetter things to come, she said.
Kristin Pink grew up on the border of the Palos Preserves in the Cook County Forest Preserve District system. Today, the ecologist is overseeing a restoration project at Cranberry Slough that has resulted in the return of many native plants.
Country Lane Road winds through part of the Palos Preserves in the Cook County Forest Preserve District system. Restoration work enables native plants to return to the area.