Monday, January 14, 2008

The History of Our Native Oaks

The oak-hickory forests and oak savannas of northern Illinois historically supported a world of living things- thousands of species of plants, animals, insects and other creatures. Open woodland communities dominated by White, Bur and Red Oaks, as well as other nut bearing trees, were teeming with life. Natural fires kept understory plants in check, allow enough light to filter through for acorns to germinate and oak seedlings to grow slowly but steadily to dominate the canopy.

Today only a fraction of these old woodlands remain. In the next 15-20 years, most of our oak-hickory woodlands may be lost. The remaining trees are old, and many are 200 or more years old. The life cycle of a naturally growing oak can be measured in 100’s of years.

What happened?
Established oaks+ new construction= dead oaks
We try to save the old oaks by building around them, but we irreparably disturb their root systems by filling, compacting and drainage changes. We prevent the tree from taking up water and nutrients it needs to survive.

When humans curbed the natural fires of the woodlands and savannas, other fire-sensitive native trees that were previously kept under control (such as box elder, ash, and sugar maple) move in along with invasive exotics like buckthorn. The understory grows denser, altering the habitat, and the old oaks that survived are now unable to reproduce, and the savannas and woodlands as they were, begin to decay and die. This not only decreases the tree diversity of the region, but it also eliminates one of the best food sources for wildlife. Acorns are a valuable food source for multitudes of birds and animals.

The Chicago area is still booming with growth, with homes and facilities expanding to support the population. The oak woodlands and savannas and the community of life they support are under pressure from the changing land use surrounding their habitat. They rarely survive development, and they are not reproducing successfully in the natural areas that are left.

The oaks we see today are ancient survivors of drought, heat, cold, fire and human interference, but they are dying out due to age and environmental stress. With few young trees to take their places, we are likely to see a dramatic change in the landscape across the region, which will impact the health, character and economy of the region- and the entire Chicagoland area.

The Next Generation of Oaks - January 2008 Green Buzz- Research and Development article

The Chicago Wilderness- Atlas of Biodiversity

Native Trees for North American Landscapes by Guy Sternberg
The Land Conservancy of McHenry County

The Land Conservancy of McHenry County Illinois or
Glacier Oaks Native Plant Nursery (Container Oak Grower) for more information on Project Quercus

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