1. Faculty of Environmental Earth Science Hokkaido University Sapporo Japan
2. Biological Laboratory, Sapporo Campus Hokkaido University of Education Sapporo Japan
3. Forestry and Forest Products Research Institute Ibaraki Japan
4. Faculty of Life and Environmental Sciences University of Tsukuba Ibaraki Japan
5. Graduate School of Environmental Science Hokkaido University Sapporo Japan
6. Japan Forest Technology Association Tokyo Japan