1. Department of Forest and Conservation Sciences, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
2. BIOGECO, UMR 1202, INRA, Université Bordeaux, 69 route d’Arcachon, Cestas F-33610, France
3. Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
4. Department of Biological Sciences, University of Notre Dame, 100 Galvin Life Science Center, Notre Dame, IN 46556, USA