1. Tomakomai Experimental Forest, Field Science Center for Northern BiosphereHokkaido University, TakaokaTomakomaiHokkaido053‐0035Japan
2. Waku Doki Science Planning19‐9 Shinmeicho 4TomakomaiHokkaido053‐0055Japan
3. Network Center of the Forest and Grassland Survey of the Monitoring Sites 1000 Project, Japan Wildlife Research Centerc/o Tomakomai Experimental Forest, Hokkaido University, TakaokaTomakomaiHokkaido053‐0035Japan