1. Laboratory of Silviculture, Division of Forest and Biomaterials Science; Graduate School of Agriculture, Kyoto Univ.; Kyoto 606-8502 Japan
2. Field Science Education and Research Center; Kyoto Univ.; Kyoto 606-8502 Japan
3. Dep. of Environmental Science & Technology; Interdisciplinary Graduate School of Science and Engineering, Tokyo Inst. of Technology; Yokohama 226-8502 Japan
4. Tokyo Univ. of Agriculture and Technology; Saiwai-cho 3-5-8 Fuchu-city Tokyo 183-8509 Japan