1. Kyushu University Forest, Kyushu Univ.; 394 Tsubakuro Sasaguri 811-2415 Japan
2. National Inst. of Polar Research; 1-9-10 Koga, Itabashi-ku Tokyo 173-8515 Japan
3. Graduate School of Biosphere Science, Hiroshima Univ.; 1-7-1, Kagamiyama Higashi-Hiroshima 739-8521 Japan