[1] Univ Calif Riverside, Dept Bot & Plant Sci, Riverside, CA 92512 USA
[2] Univ Utah, Dept Biol, Salt Lake City, UT 84112 USA
[3] Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA
[4] US Forest Serv, Northern Res Stn, Syracuse, NY 13210 USA
[5] Boston Univ, Dept Earth & Environm, Boston, MA 02215 USA
[6] North Carolina State Univ, Dept Forestry & Environm Resources, Raleigh, NC 27695 USA
[7] Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA
[8] Univ Dist Columbia, Washington, DC USA
[9] Natl Socioenvironm Synth Ctr, Annapolis, MD USA