1. College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
2. School of Grassland Science, Beijing Forestry University, Beijing 100083, China
3. Department of Biological Sciences, Salisbury University, Salisbury, MD 21801, USA
4. Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry, Guangzhou 510520, China
5. Department of Mathematical Sciences, Salisbury University, Salisbury, MD 21801, USA
6. College of Plant Protection, South China Agricultural University, Guangzhou 510642, China