We thank the Administration Bureau of Shennongjia National Nature Reserve for their support, and Yao H, Yu H L, and Yu P L for field assistance, Alica Krzton for useful suggestions and editing the English in the manuscript, and two anonymous revzewers for useful suggestions that improved the manuscript. This work was supported by the National Natural Science Foundation of China (30870375 and 31071937), the Project of Public Benefit for the Forestry (201104073), and the National Basic Research Program of China (2007CB411600).