About the Authors
Institute of Plant Sciences and Botanical Garden; University of Bern, Bern, Switzerland
Oeschger Center, University of Bern, Bern, Switzerland
Max-Planck-Institute for Biogeochemistry, Jena, Germany
The authors have declared that no competing interests exist.
Provided forest inventory data: DH EDS. Conceived and designed the experiments: SB MF DH DP EDS. Performed the experiments: SB. Analyzed the data: SB DP MF. Contributed reagents/materials/analysis tools: SB. Wrote the paper: SB DP MF.