ACKNOWLEDGMENTS
This work was supported by the Knut and Alice Wallenberg Foundation (#2015.0047). Antoine Vernay was funded by the Kempe foundation (SMK-1743). The authors thank the ecophysiological team of Forest Ecology and Management department (SLU) and researchers working on “Carbon and Water Branchpoints in Boreal Forests” project for their helpful comments. We thank the SLU stable isotope laboratory (SSIL) staff for isotopic analysis and SITES staff for their financial support and their help in the field and for providing data. Finally, we thank Dr Thomas Perot for his help with the statistical analyses. Financial support for Ram Oren was provided by the Erkko Visiting Professor Programme of the Jane and Aatos Erkko 375thAnniversary Fund through the University of Helsinki.