1. Key Laboratory of Forest Resources Conservation and Utilization in the Southwest Mountains of China Forestry and Grassland Administration, Southwest Forestry University, Kunming 650051, P. R. China
2. Research Center for Analysis and Measurement, Kunming University of Science and Technology, Kunming 650093, P. R. China
3. Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130022, P. R. China