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Saving Soils in the Forest Preserves
Nature Bulletin No. 562-A April 12, 1975
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
SAVING SOILS IN THE FOREST PRESERVES
The Little Red Schoolhouse nature center and its surrounding areas
offer some interesting examples of how nature slowly rebuilds and
protects soils if given a chance and plenty of time. Along the
neighboring highways in those hilly Palos preserves you can also see
some excellent demonstrations of how, in various ways, the Forest
Preserve District has hastened the processes of building soils and
provided the protection that saves them.
For
example, when Willow Springs Road was paved from Archer Ave.
to 107th St., some deep cuts were gouged through those hills. The
highway department permitted us to sod and plant the steep ugly slopes
to prevent erosion and make them more attractive. Between 95th St. and
the schoolhouse entrance they were planted with black locust seedlings.
That tree not only has dense fibrous roots which hold soil in place; it
grows fast and serves as a "nurse crop" protecting other plants. Also,
being a legume, its roots harbor nitrogen-fixing bacteria that enrich the
soil.
On deeper cuts, south of the schoolhouse entrance and also at Archer
Ave., we planted a mixture of shrubs such as coralberry, snowberry,
wild roses and sumac, which prevented erosion and have become dense
masses furnishing food and cover for wildlife. On 107th St., about two
miles west of Willow Springs Road, you can see how we planted and
protected the steep hillsides with mixtures of vines, shrubs, and
fast-growing trees such as black locust, poplar, silver maple and
boxelder.
Much of the land in our Palos preserves, originally forested, had been
cleared and farmed before we acquired it. Many of those old fields have
been reforested with mixtures of native hardwoods including ash, elm,
maples, poplars, black walnut and oaks. Typical examples, now grown
to considerable size, may be seen along 107th St. and also on Kean
Ave. between 95th and 107th Streets. Nowadays we use tractor-drawn
machines that plant from 2000 to 7000 seedlings per day, depending
upon the soil conditions.
Roughly paralleling the highways in many locations, and the edges of
reforested areas, you may notice plowed strips from 16 to 20 feet wide.
These are fire breaks that protect the woodlands and young plantings
from fires.
The Swallow Cliff picnic area, on the hilltop at US 45 and 119th St.,
demonstrates what we have done to rebuild the soil and save the trees in
several heavily used areas. Many years of abuse, including unrestricted
traffic by automobiles, had destroyed the grasses and compacted the
soil on the eastern portion next to US 45. Many trees had died or were
very sick.
After developing a new picnic area west of it, we erected a fence around
the old one. Its surface was loosened, covered with rich black dirt and
an 3-inch layer of rotted leaves, and sown with a mixture of grass seed.
The steeper slopes were sodded. Today that old picnic area, including
its grasses, wildflowers, shrubs and trees, has a healthy natural
appearance.
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Update: June 2012
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