1. Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstraße 111, 8903 Birmensdorf, Switzerland
2. Earth Environmental Systems, Graduate School of Environmental Studies, Nagoya University, Furo‐cho, Chikusa, Nagoya 464–8601, Japan
3. Institute of Plant Science, ETH Zürich, Eschikon 33, 8315 Lindau, Switzerland