Shrubs
by Stephen Packard

hese children are the Mighty Acorns. Throughout Chicago Wilderness they are learning to discipline weedy brush under the guidance of trained volunteers and staff.

Of course, a little weediness in a child’s life — or in a natural ecosystem — is an entirely natural thing. But the children here are learning the difference between freedom and chaos. When weeds threaten to overwhelm and destroy everything else, then it’s time to recognize that there’s a problem and do something about it.

The kids here are cutting saplings of buckthorn, gray dogwood, white ash, and elm. A bit of orange flagging (not visible above) wrapped around a shrub stem was placed there by one of the leaders, alerting the young crew not to cut that particular shrub. It’s a hawthorn, viburnum, hazelnut, plum, or some other species that’s a part of this ecosystem.

The tall dark-green trees at top left are open woodland — bur and scarlet oak and shagbark hickory. The tree on the horizon to the right of the oaks is an elm, recognizable by the fine branches that flare out toward the top. Elm, ash, and buckthorn are invaders in these uplands. Gray dogwood is a native shrub that can become aggressive, to the detriment of the system. The open spaces between the oak groves here are naturally a mix of savanna and grassy shrubland. All three of the natural communities here — oak-hickory woodland, savanna, and shrubland — are threatened with obliteration if we do nothing to maintain them. The hundreds of rare and uncommon species this site is prized for would die out, and the resulting thicket would be of little interest or value to wildlife or people.

One native invasive species is poison ivy, often becoming a dominant plant in unburned shrublands and woods. Here the ivy was almost eliminated by many years of prescribed fire; but this area now hasn’t had a burn for six years. Somebody should get the controlled fire program back in gear or tell these stewards to start wearing long pants again.

Until the recent work of Marlin Bowles of the Morton Arboretum, Ed Collins of the McHenry County Conservation District, Christopher Whelan of Midewin National Tallgrass Prairie, and others, the shrublands were little known or protected. Yet there are rare bird, wildflower, and other species that depend on shrublands. Bell’s vireo and the eared false-foxglove are two examples of such species that are globally rare. Other shrublanders include the blue-winged warbler, brown thrasher, and field sparrow, all of which thrive in the area where these students are working. The chestnut-sided warbler is a shrub lover that has returned to breed here only in the last decade.

In this context, a thicket of dogwood, ash, buckthorn, and poison ivy isn’t "natural succession." It’s gradual death to an ancient ecosystem and its ancient species. Fire allows these ecosystems the vigor of perpetual youth. Cutting saplings and aggressive shrubs is a poor substitute for fire, but in the short term it allows us to save the highest potential of some sites, while exercising some of our own.

Somme Prairie Grove Preserve is protected and managed by the Forest Preserve District of Cook County. Restoration assisted by the volunteers of the North Branch Restoration Project, Mighty Acorns, and the Friends of Northbrook Forest Preserves.

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