1. School of Forest Resources and Environmental Science; Michigan Technological University; Houghton MI 49931 U.S.A.
2. Department of Forest and Rangeland Stewardship and Graduate Degree Program in Ecology; Colorado State University; Fort Collins CO 80523 U.S.A.
3. U.S. Fish and Wildlife Service; Great Dismal Swamp National Wildlife Refuge; Suffolk VA 23434 U.S.A.
4. Department of Plant Sciences, Peatland Ecology Research Group and Centre for Northern Studies; Université Laval; 2425 de l'Agriculture Québec QC G1V 0A6 Canada