1. School of Economics and Management, Beijing Forestry University, Beijing 100083, China
2. College of Forestry, Beijing Forestry University, Beijing 100083, China
3. Institute of Western China Economic Research, Southwestern University of Finance and Economics, Chengdu 611130, China
4. Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
5. College of Information Technology, Shanghai Jian Qiao University, Shanghai 201306, China
6. School of Tourism, Shanghai Normal University, Shanghai 200234, China
7. Chinese Academy of Environmental Planning, Beijing 100012, China