Site being restored as an oak savanna
Where: Near the Rock County Campus where County F meets Highway 51 just south of Highway 14. The area being restored is about two acres and is directly north of the Rock County Health Department,
How did they pay for it? The approximately $10,000 needed to remove invasive species and reseed the small plot came from a one-time, $1.8 million payment from the American Transmission Co. when the company built a high-voltage transmission line across Rock County.
Why did they do it? Oak savannas rank with tallgrass prairies as the most threatened plant community in the Midwest, according to Wisconsin Department of Natural Resources information. Oak trees are native to Wisconsin. Savannas are transition areas on the edges of prairies—in this case, the Rock Prairie. They are typically grassy, open areas with some trees. Once restored, this savanna will support small mammals, woodpeckers, toads and other creatures, said Anne Miller, county conservationist.
Miller and others have worked for 18 months to remove non-native species such as buckthorn and garlic mustard. They also removed trash trees and cut the stumps to ground level.
The buckthorn had shaded out the grass and left the soil susceptible to erosion, Miller said.
With the brush gone, the trees will fill out nearly to the ground. The old branches follow the slope of the soil and make what look like green tunnels or crawlspaces, Miller said.
If you don’t remember what the spot looked like before the brush was cleared, compare it to the patch of woods located farther south behind the Rock County Health Department, 3328 N. Highway 51, Janesville. The woods is a continuation of the spot that has been cleared on the north side of the health department.
On garlic mustard: The plant with the white flowers in the lower-right corner of the photo is garlic mustard. It is an invasive species that can take over a forest floor, crowding out delicate native plants. You can pull the plant from your yard or while you are using bike paths or public parks. Don’t leave the plants on the driveway or in the grass—they will keep growing and go to seed. Bag them with your household trash or burn them.
To learn more: Visit wi.dnr.gov. Search for “oak savannas” or “garlic mustard.”