1. Precision Forestry Key Laboratory of Beijing, Beijing Forestry University, Beijing 100083, China
2. Department for Earth Observation, Friedrich Schiller University Jena, Loebdergraben 32, 07743 Jena, Germany
3. Faculty of Electrical Engineering and Information Technology, Ruhr University Bochum, Universitaetsstr. 150, D-44801 Bochum, Germany
4. State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China
5. Instiute of Eco-Environmental Research, Guangxi Academy of Sciences, Nanning 530007, China
6. Surveying and 3S Engineering Research Center, Beijing Forestry University, Beijing 100083, China