First Author:   Yasushi Shoji Hokkaido University yshoji@for.agr.hokudai.ac.jp         Second Author: Koichi Kuriyama Waseda University kkuri@waseda.jp         Third Author: Taro Mieno University of Illinois at Urbana-Champaign t.mieno@hotmail.co.jp         Fourth Author: Yohei Mitani University of Colorado at Boulder mitani@colorado.edu