1. Hokkaido Research Center, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
2. Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
3. Tadami Beech Center, 2590 Machishita, Tadami, Tadami-machi, Fukushima 968-0421, Japan