1. College of Natural Resources; University of Idaho; Moscow ID 83844 USA
2. Bordeaux Sciences Agro, UMR INRA-ISPA 1391; Gradignan 33195 France
3. Nicholas School of the Environment; Duke University; Durham NC 27708 USA
4. Department of Natural Resources and the Environment; University of New Hampshire; Durham NH 03824 USA
5. Department of Botany; University of Wisconsin-Madison; Madison WI 53705 USA
6. US Forest Service, Pacific Northwest Research Station; Corvallis OR 97331 USA
7. Grassland, Soil & Water Research Laboratory USDA-Agricultural Research Service; Temple TX 76502 USA
8. INRA Nancy, UMR INRA-UL 1137 Ecologie et Ecophysiologie Forestières; Champenoux 54280 France
9. Department of Geography; State University of New York; Buffalo NY 14261 USA
10. Pacific Northwest National Laboratory; Richland WA 99352 USA
11. Department of Earth System Science; Woods Institute for the Environment, and Precourt Institute for Energy, Stanford University; Stanford CA 94305 USA