1. Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, U.S.A.
2. Bureau of Air Management, Wisconsin Department of Natural Resources, 101 S. Webster Street, Madison, WI 53707, U.S.A.
3. Geological Sciences 450 Serra Mall, Building 320, Stanford University, Stanford, CA 94305, U.S.A.
4. Urban Ecology Center, 1500 E. Park Place, Milwaukee, WI 53211, U.S.A.
5. USDA Forest Service, Portland Forestry Sciences Lab, 620 SW Main, Suite 400, Portland, OR 97205, U.S.A.