1. Research Unit of Forest Dynamics, Research Group of Ecosystem Ecology Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland
2. Department of Earth Sciences, Research Group of Ocean Biogeochemistry University of Oxford Oxford UK
3. Department of Environmental Systems Science, Group of Grassland Sciences ETH Zurich Zürich Switzerland
4. Department of Environmental Systems Science, Institute of Terrestrial Ecosystems ETH Zurich Zürich Switzerland