Big Woods

From Wikipedia, the free encyclopedia

Big Woods refers to a type of temperate hardwood forest found in south-central Minnesota. The dominant trees are American elm, basswood, sugar maple, and red oak. The understory is composed of ironwood, green ash, and aspen. The Big Woods would have once covered 5000 square miles in a diagonal strip 100 miles long and 40 miles wide. Today most of this region has been cleared for agriculture and urban development. Remnant and secondary stands of Big Woods remain in parks and other protected areas. "Big Woods" is a direct translation of the name given to the region by French explorers: Grand Bois.

The soil of the Big Woods is thick glacial till of crushed limestone, deposited by the Des Moines lobe of the Wisconsin glaciation 10,000 years ago. The landscape is characterized by round hills and numerous undrained lakes left by melting ice blocks. These hills and lakes suppressed fires that were instrumental forces on the prairie to the west and the oak savanna to the south and east. The Minnesota and Crow Rivers flow through the region, but many of the 100 or so lakes had no inlets or outlets.

The Big Woods have a growing season of about 145-150 days and an average annual precipitation of 30 inches.