1. College of Forestry, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
2. The Key Laboratory of Oasis Eco-Agriculture, Xinjiang Production and Construction Corps, Shihezi University, No. 221, Beisi Road, Shihezi 832000, China
3. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, No. 20, Xiangshan Nanxin Cun, Haidian District, Beijing 100093, China