1. Joint Research Unit CTFC ‐ AGROTECNIO 25280 Solsona Spain
2. CREAF Bellaterra (Cerdanyola del Vallès) E08193 Catalonia Spain
3. Dendrosciences Swiss Federal Institute for Forest, Snow and Landscape Research WSL Zürcherstrasse 111 CH‐8903 Birmensdorf Switzerland
4. Department of Environmental Sciences – Botany Basel University Schönbeinstrasse 6 CH‐4056 Basel Switzerland
5. Laboratory of Plant Ecology Department of Plants and Crops Faculty of Bioscience Engineering Ghent University Coupure links 653 B‐9000 Ghent Belgium
6. Universitat Autònoma de Barcelona E08193 Bellaterra (Cerdanyola del Vallès) Catalonia Spain