1. Institute for Space Sciences; Free University of Berlin; Berlin 12165 Germany
2. Department of Global Ecology; Carnegie Institution for Science; Stanford CA 94305 USA
3. NASA Goddard Space Flight Center; Greenbelt MD 20771 USA
4. International Institute for Geo-Information Science and Earth Observation; P.O. Box 6 7500 AA Enschede The Netherlands
5. Plant Functional Biology and Climate Change Cluster; University of Technology Sydney; Sydney NSW 2007 Australia
6. School of Natural Resources; University of Nebraska - Lincoln; Lincoln NE 68583 USA