Affiliation: | Department of Environmental Sciences, Laboratory of Soil Science and Geology, Wageningen University, PO Box 37, 6700 AA Wageningen, The Netherlands;;Department of Environmental Sciences, Terrestrial Ecology and Nature Management, Wageningen University, Bornse Steeg 69, 6708 PD Wageningen, The Netherlands;;Natura, Applied Biology and Environmental Eng. Le Saucy 17, 2722 Les Reussilles, Switzerland;;University of Helsinki, Department of Forest Ecology, PO Box 24, FIN-00014 Helsinki, Finland;;Department of Plant Ecology, Ecology Building, Lund University, S-223 62 Lund, Sweden |