1. Max-Planck Institute for Biogeochemistry; Box 100164 07701 Jena Germany
2. Institute of Botany; University of Basel; 4056 Basel Switzerland
3. Department of Forest Ecosystems and Society; Oregon State University; 321 Richardson Hall Corvallis OR USA
4. Institute of Social Ecology Vienna; Alpen-Adria University Klagenfurt; Wien, Graz Schottenfeldgasse 29 1070 Vienna Austria
5. Laboratoire des Sciences du Climat et de l'Environnement, IPSL, CEA CNRS UVSQ; Centre d'Etudes Ormes des Merisiers; 91191 Gif-sur-Yvette France