Affiliation: | a Research Group of Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium b Division of Forest, Nature and Landscape, University of Leuven, Celestijnenlaan 200E, B-3001 Leuven, Belgium c Slovenian Forestry Institute, Ve?na pot 2, 1000 Ljubljana, Slovenia |