1. Department of Forestry Michigan State University East Lansing Michigan 48824 USA
2. Ecology, Evolutionary Biology, and Behavior Program Michigan State University East Lansing Michigan 48824 USA
3. Department of Statistics University of Missouri Columbia Missouri 65211 USA
4. Department of Biology Tufts University Medford Massachusetts 02155 USA
5. Harvard Forest Harvard University Petersham Massachusetts 01366 USA
6. Department of Biological Sciences University of Rhode Island Kingston Rhode Island 02881 USA