1. Department of Ecology, College of Ecology and Environment, Nanjing Forestry University, Nanjing 210037, China
2. Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
3. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
4. Department of Geography and Planning, University of Saskatchewan, 117 Science Place, Saskatoon, SK S7N5C8, Canada