1. Graduate School of Agriculture, Hokkaido University, Nishi 9, Kita 9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
2. Department of Forest Vegetation, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
3. Shikoku Research Center, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 2-915 Asakuranishi, Kochi, Kochi 780-8077, Japan
4. Faculty of Environmental Earth Science, Hokkaido University, Nishi 5, Kita 10, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
5. Department of Wildlife Biology, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
6. Center for Biodiversity and Climate Change, Forestry and Forest Products Research Institute, Forest Research and Management Organization, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
7. Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan