1. College of Forestry, Northwest A&F University, Yangling, People’s Republic of China
2. Boone Pickens School of Geology, Oklahoma State University, Stillwater, Oklahoma, USA
3. State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, People’s Republic of China