1. Forestry Economics and Management, College of Economics and Management, Northeast Forestry University, Harbin 150040, China
2. Forestry Program Study, Muhammadiyah University of Palembang, Palembang 30263, Indonesia
3. Forestry Department, Muhammadiyah University of West Sumatra, Padang 25172, Indonesia
4. School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China