1. School of Forest Resources, University of Maine, Orono, ME 04469.
2. Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA 94720.
3. Ecological Plant Geography, Faculty of Geography, University of Marburg, Marburg 35037, Germany.
4. Atmospheric Sciences Research Center, University at Albany, State University of New York, Albany, NY 12203.
5. Department of Environmental Biology, State University of New York College of Environmental Science and Forestry (SUNY–ESF), Syracuse, NY 13210.