1. Max‐Planck‐Institute for Biogeochemistry, Hans‐Knöll‐Str. 10, D‐07745 Jena, Germany
2. Plant Ecology, Albrecht‐von‐Haller‐Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, D‐37073 Göttingen, Germany
3. Institute of Energy and Environment, Torgauer Str. 116, D‐04347 Leipzig, Germany
4. Department of Geography, University of Cologne, Albertus‐Magnus‐Platz, D‐50923 Köln, Germany