1. U.S. Geological Survey, 345 Middlefield Rd., ms 962, Menlo Park, CA 94025, USA,
2. Department of Earth System Science, University of California, Irvine, CA, USA,
3. Natural Resources Canada, 1219 Queen St. E. Ste. St. Marie, Ontario, Canada,
4. Forest Ecosystem Ecology, University of Wisconsin, Madison, WI 53706, USA,
5. Department of Environmental Sciences, Duke University, Durham, NC 27706, USA,
6. ERIM International, PO Box 134008 Ann Arbor, MI 481103‐4008, USA