1. Key Laboratory of Environment Change and Resources Use in Beibu Gulf (Guangxi Teachers Education University), Ministry of Education Nanning P. R. China
2. Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation (Guangxi Teachers Education University) Nanning P. R. China
3. Institute of Applied EcologyChinese Academy of Sciences Shenyang China
4. Department of Forestry and Natural Resources, TP Cooper BuildingUniversity of Kentucky Lexington KY USA