1. College of Forestry; Key Laboratory for Forest Resources and Ecosystem Processes of Beijing; Beijing Forestry University; Beijing 100083 China
2. School of Life Science; Lanzhou University; Lanzhou 730000 China
3. School of Mathematics and Computer Science; Northwest University for Nationalities; Lanzhou 730030 China
4. Key Laboratory for Bio-resources and Eco-environment; College of Life Science; Sichuan University; Sichuan 610065 China
5. INRA; UMR1202 BIOGECO; F-33610 Cestas France
6. Univ. Bordeaux; BIOGECO; UMR 1202; F-33615 Pessac France