1 National Engineering Laboratory for Applied Technology of Forestry & Ecology in Southern China, Central South University of Forestry and Technology, Changsha 410004, China.
2 College of Biological Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China.
3 National Engineering Laboratory for Applied Technology of Forestry & Ecology in Southern China, Central South University of Forestry and Technology, Changsha 410004, China; shuguang.liu@yahoo.com.