1. Dept of Forest Sciences; PO Box 27, FI-00014 University of Helsinki; Finland
2. Inst. of Statistical Mathematics - Data Science; 10-3 Midori, Tachikawa JP-190-8562 Tokyo Japan
3. Nanzan University; Japan
4. Lab. Ecology and Systematics, Faculty of Science, Univ. of the Ryukyus Nishihara; Nishihara JP-903-0213 Okinawa Japan