1. Institute of Ecology and Geobotany, Yunnan University, 2 Northern Green-Lake Road, Kunming 650091, China
2. College of Forestry, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China
3. Laboratory of Forest Management and Spatial Information Techniques, Universiteit Gent, Coupure Links 653, Gent 9000, Belgium
4. Flemish Institute for Technological Research, Boeretang 200, Mol 2400, Belgium