1. Department of Chemical and Biochemical Engineering; Technical University of Denmark; DK-2800; Lyngby; Denmark
2. Department of Biogeography; University of Bayreuth; Universitaetsstr. 25; D-95440; Bayreuth; Germany
3. Swiss Federal Institute for Forest Snow and Landscape Research WSL; Forest Dynamics; Zürcherstrasse 111; CH-8903; Birmensdorf; Switzerland
4. Department Global Ecology; CREAF-CSIC Barcelona; Edifici C, UAB o8193; Bellaterra; Spain
5. Centre for Ecology and Hydrology; Environment Centre Wales; Deiniol Road, UK-LL57 2UW; Bangor; Wales; UK
6. Institute of Botany; University of Basel; Schoenbeinstr. 6; CH-4056; Basel; Switzerland
7. University of Antwerp; Plant and Vegetation Ecology; Universiteitsplein 1; BE-2610; Wilrijk; Belgium
8. ETH Zurich Forest Ecology; Environmental Sciences; Universitätstrasse 16; CH-8092; Basel; Switzerland
9. IVL Swedish Environmental Research Institute; P.O. Box 210 60, SE-100 31; Stockholm; Sweden