1. Key Laboratory of Forest Ecology and Management; Institute of Applied Ecology; Chinese Academy of Sciences; Shenyang 110016 China
2. University of Chinese Academy of Sciences; Beijing 100049 China
3. Sydney Institute of Agriculture; School of Life and Environmental Sciences; The University of Sydney; Camden NSW 2570 Australia
4. Department of Ecology; College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education; Peking University; Beijing 100871 China
5. Environmental Studies Department; University of California; Santa Cruz CA 95064 USA