FINDING OAK SAVANNA HABITATS IN MINNESOTA

Steven F. Nelson, East Central Woodland Owners Council

Without fire, oak savannas become unnaturally overstocked and turn into closed forests.

Native vegetation descriptions from the NRCS' Web Soil Survey, for oak forests and oak savanna, shows information similar to Rosendahl & Butters information from 1928 "Trees and Shrubs of Minnesota". Most striking is the phrase …"even the Big Woods may be considered to be a prairie grove on an unprecedentedly large scale and with a corresponding diversity of flora". Indeed, almost two thirds of Wright County's acreage are soils that support either oak savanna or mixed hardwoods with prairie grasses, even though most of it is either farmed or developed.

There is no less than 32,000 acres of restorable oak savanna in southern Minnesota, and roughly half that amount in northwestern Minnesota from Douglas to Red Lake Counties.

Finding and mapping the oak savanna and mixed hardwood with prairie grasses vegetation types helps:

1. Change monoculture forests back into native forests
2. Figure-out needed changes to oak wilt control
3. Cleaning-up impaired waters
4. Finding tree species such as bicolor oak that can replace ash habitats
5. Show which soils will be most likely to support hardwoods if climate change pushes hardwood forests north and northeast
6. Completion of vegetation/biological surveys of public and private lands

Lake Mariah State Park is largely oak savanna. Kathio State Park has 30+ acres of oak savanna.

Once county oak savanna and mixed hardwoods with prairie grasses inventories are done, mapping can take place, perhaps starting at the township level. Once remnant oak savannas and mixed hardwoods with prairie grasses are identified, restoration work can be planned, and markets for woody biomass, biofuels and lumber will be enhanced.

Suggestions for Reading

"Trees and Shrubs of Minnesota" 1928, Rosendahl and Butters, University of Minnesota