1. Forestry Research Institute, Hokkaido Research Organization, Bibai, Hokkaido, Japan
2. Hokkaido Research Centre, Forestry and Forest Products Research Institute, Forest Research and Management Organization, Sapporo, Hokkaido, Japan
3. Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan
4. Education and Research Center, the University of Tokyo Forests, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, Japan