1. Chair of Tree Physiology, Institute of Forest Sciences, University of Freiburg, Georges‐Köhler‐Allee 53/54, 79110 Freiburg, Germany
2. Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
3. Forest Research Institute Baden‐Württemberg, Department of Soil and Environment, Wonnhaldestraße 4, 79100 Freiburg, Germany