1. Irstea; UR EMGR Ecosystèmes Montagnards; 2 rue de la Papeterie-BP 76; F-38402; St-Martin-d'Hères; France
2. Laboratoire d'Ecologie Alpine; UMR-CNRS 5553; Université Joseph Fourier; BP 53; 38041; Grenoble Cedex 9; France
3. CIRAD; UR105 Forest Ecosystem Goods and Services; TA C-105/D, Campus de Baillarguet; F-34398; Montpellier Cedex 5; France
4. Landscape Dynamics; Swiss Federal Research Institute WSL; 8903; Birmensdorf; Switzerland
5. Max Planck Institute for Biogeochemistry; 07745; Jena; Germany
6. Forest Ecology and Conservation Group; Department of Plant Sciences; University of Cambridge; Downing Street; Cambridge; CB3 2EA; UK