1. Tohoku Research Center, Forestry and Forest Products Research Institute, Morioka 020-0123, Japan
2. Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto, Japan
3. Department of Forest Management, Forestry and Forest Products Research Institute, Tsukuba, Japan
4. Tama Forest Science Garden, Forestry and Forest Products Research Institute, Hachioji, Tokyo, Japan