1. Department of Environmental Ecology, Graduate School of Environmental Science, Okayama University, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
2. Faculty of Agriculture, Okayama University, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
3. Sumitomo Forestry Corporation, 1-3-2 Ohtecho, Chiyoda, Tokyo 100-8270, Japan
4. Department of Forest Sciences, National University of Mongolia, Ulaanbaatar 210646, Mongolia