1. Forest Research Institute Hokkaido Research Organization Bibai Hokkaido 079–0198 Japan
2. Shiretoko Museum Honmachi 49, Shari Shari‐gun Hokkaido 099–4113 Japan
3. Field Science Center for Northern Biosphere Hokkaido University N9 W9, Kita‐ku Sapporo Hokkaido 060–0809 Japan
4. Aqua Restoration Research Center Public Works Research Institute KawashimaKasada‐machi Kakamigahara Gifu 501–6021 Japan
5. Department of Forest Science, Graduate School of Agriculture Hokkaido University N9 W9 Sapporo Hokkaido 060–8589 Japan