1. School of Civil Engineering and Transportation, Northeast Forestry University, Harbin 150040, China
2. Aulin College, Northeast Forestry University, Harbin 150040, China
3. Investment and Financing Consulting Business Department, China International Engineering Consulting Corporation, Beijing 100048, China
4. Department of Economics and Rural Development, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium