1. Forest Ecology & Stable Isotope Research Center, College of Forestry; Fujian Agriculture & Forestry University; Fuzhou 350002 PR China
2. State Key Laboratory of Soil & Sustainable Agriculture; Institute of Soil Science, Chinese Academy of Sciences; Nanjing 210008 PR China
3. College of Natural Resources Management & Tourism; Mwalimu Julius K. Nyerere University of Agriculture & Technology; P.O. Box 976 Musoma Tanzania
4. Department of Botany; Panjab University Chandigarh; Chandigarh 160014 India
5. CAS Key Laboratory of Forest Ecology and Management; Institute of Applied Ecology, Chinese Academy of Sciences; Shenyang 110016 PR China