1. Graduate School of Agricultural Science, Kobe University, Kobe, Japan
2. Laboratoy of Forests and their Local Surroundings, 3-3-2-1017 Sumiregaoka, Takarazuka 665-0847, Japan
3. Forestry Preservation Division, Hiroshima Prefectural Government, Hiroshima, Japan
4. Faculty of Agriculture, Kobe University, Kobe, Japan
5. College of Bioresource Sciences, Nihon University, Fujisawa, Japan
6. Lab. Forest Plant Ecology, Northeast Forestry University, Harbin, China