U.S. Fish and Wildlife Service
Forest ecosystems are defined as land areas dominated by trees where the tree canopy covers at least 10 percent of the ground area. Forest ecosystems play a primary role in the ecology, culture and economy of the Great Lakes - Big Rivers Region. Forests provide raw materials for industry, as well as food, fuel, medicine, filtered water, and shelter for humankind.
Midwestern forests types are diverse and abundant and include spruce-fir; red, white, short-leaf, and jack pine; oak-hickory; maple-mixed hardwoods; aspen-birch; elm-ash-cottonwood; and oak-gum-cypress forests. However, these forests have changed substantially since European settlement. Because pre-settlement disturbances were rare, most of the Region's forests were mature, old-growth forests. Timber harvest strategies have greatly reduced the average age of forests and they have become much more homogeneous in both species composition and age. The long-term decline in early successional forests across the Region has contributed to the decline of many bird species. Selective harvesting, fire suppression, urban sprawl, and cessation of agricultural abandonment have contributed to the present imbalance in distribution of young forests.
Forest ecosystems are also threatened by invasions of exotic species of insects, disease pathogens, and plants. Exotic and invasive species from Europe and Asia have damaged Midwestern forests. Some of the most devastating invasions have been from herbivorous insects and plant pathogens. These include the European and Asian gypsy moths, Dutch elm disease, and white pine blister rust. Significant environmental change may result from forest invasions, including loss of species, changes in ecosystem structure and function and other irreversible occurrences.
To learn more about forest ecosystems, visit the sites of our partner, the U.S. Forest Service:
Restoring and Maintaining Healthy Forest Ecosystems in the Interior West
The 20th Century has taught us some important lessons about forest ecosystems, and the way they respond to human activities. To achieve healthy forest ecosystems in the Interior West, several things need to be done.
- Influences on Forest Ecosystems
Before the arrival of European settlers, fire had a central role in the evolution and function of California's extremely diverse ecosystems. During the past century, fire has often been portrayed as a destructive force that should always be eliminated to "protect" ecosystems. Attitudes toward fire are shifting once again: the awareness of the role of fire in ecosystem dynamics and function is increasing. Managing fire frequency and intensity will help maintain biological diversity, integrity, and sustainability.