@article{d78a64c1916f46c0b2b63ef838b991ca,
title = "Pervasive decreases in living vegetation carbon turnover time across forest climate zones",
abstract = "Forests play a major role in the global carbon cycle. Previous studies on the capacity of forests to sequester atmospheric CO2 have mostly focused on carbon uptake, but the roles of carbon turnover time and its spatiotemporal changes remain poorly understood. Here, we used long-term inventory data (1955 to 2018) from 695 mature forest plots to quantify temporal trends in living vegetation carbon turnover time across tropical, temperate, and cold climate zones, and compared plot data to 8 Earth system models (ESMs). Long-term plots consistently showed decreases in living vegetation carbon turnover time, likely driven by increased tree mortality across all major climate zones. Changes in living vegetation carbon turnover time were negatively correlated with CO2 enrichment in both forest plot data and ESM simulations. However, plot-based correlations between living vegetation carbon turnover time and climate drivers such as precipitation and temperature diverged from those of ESM simulations. Our analyses suggest that forest carbon sinks are likely to be constrained by a decrease in living vegetation carbon turnover time, and accurate projections of forest carbon sink dynamics will require an improved representation of tree mortality processes and their sensitivity to climate in ESMs.",
keywords = "Carbon cycle, Forest carbon stocks, Forest productivity, Tree mortality",
author = "Kailiang Yu and Smith, {William K.} and Trugman, {Anna T.} and Richard Condit and Hubbell, {Stephen P.} and Jordi Sardans and Changhui Peng and Kai Zhu and Josep Pe{\~n}uelas and Maxime Cailleret and Tom Levanic and Arthur Gessler and Marcus Schaub and Marco Ferretti and Anderegg, {William R.L.}",
note = "Funding Information: ACKNOWLEDGMENTS. We thank the editor and 2 anonymous reviewers for insightful comments that improved the manuscript. We thank Thomas A. M. Pugh and Thomas Ward Crowther for discussion of this paper during the revisions. W.R.L.A. acknowledges funding from the David and Lucille Packard Foundation, National Science Foundation Grants 1714972 and 1802880, the US Department of Agriculture (USDA) National Institute of Food and Agriculture, the Agricultural and Food Research Initiative Competitive Programme, and Ecosystem Services and Agro-ecosystem Management Grant 2018-67019-27850. J.S. and J.P. acknowledge funding from European Research Council Synergy Grant ERC-SyG-2013-610028 IMBALANCE-P. W.K.S. acknowledges funding from NASA Terrestrial Ecosystems Grant 80NSSC19M0103. A.T.T. acknowledges support from USDA National Institute of Food and Agriculture Postdoctoral Research Fellowship Grant 2018-67012-28020. K.Z. acknowledges funding from the Faculty Research Grant awarded by the Committee on Research from the University of California, Santa Cruz. All CMIP5 data are available at https://pcmdi.llnl.gov/mips/cmip5/data-portal.html. We acknowledge the World Climate Research Programme{\textquoteright}s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups (listed in SI Appendix) for producing and sharing their model output. For CMIP, the US Department of Energy{\textquoteright}s Program for Climate Model Diagnosis and Intercomparison provided coordinating support and led the development of software infrastructure in partnership with the Global Organization for Earth System Science Portals. The evaluation was partly based on data that was collected by partners of the official United Nations Economic Commission for Europe International Cooperative Programme Forests Network (http:// icp-forests.net/contributors). Part of the data were cofinanced by the European Commission (data downloaded on October 15, 2018). We further thank David Clark, John Byrne, Alan Taylor, Pete Fule, Mark Harmon, Tom Veblen, Nathan Stephenson, Adrian Das, and Phil van Mantgem for sharing forest plot data. Funding for some of the long-term forest plot data came from the US Geological Survey{\textquoteright}s Land Change Science Program. Funding Information: We thank the editor and 2 anonymous reviewers for insightful comments that improved the manuscript. We thank Thomas A. M. Pugh and Thomas Ward Crowther for discussion of this paper during the revisions. W.R.L.A. acknowledges funding from the David and Lucille Packard Foundation, National Science Foundation Grants 1714972 and 1802880, the US Department of Agriculture (USDA) National Institute of Food and Agriculture, the Agricultural and Food Research Initiative Competitive Programme, and Ecosystem Services and Agro-ecosystem Management Grant 2018-67019-27850. J.S. and J.P. acknowledge funding from European Research Council Synergy Grant ERC-SyG-2013-610028 IMBALANCE-P. W.K.S. acknowledges funding from NASA Terrestrial Ecosystems Grant 80NSSC19M0103. A.T.T. acknowledges support from USDA National Institute of Food and Agriculture Postdoctoral Research Fellowship Grant 2018-67012-28020. K.Z. acknowledges funding from the Faculty Research Grant awarded by the Committee on Research from the University of California, Santa Cruz. All CMIP5 data are available at https://pcmdi.llnl.gov/mips/cmip5/data-portal.html. We acknowledge the World Climate Research Programme?s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups (listed in SI Appendix) for producing and sharing their model output. For CMIP, the US Department of Energy?s Program for Climate Model Diagnosis and Intercomparison provided coordinating support and led the development of software infrastructure in partnership with the Global Organization for Earth System Science Portals. The evaluation was partly based on data that was collected by partners of the official United Nations Economic Commission for Europe International Cooperative Programme Forests Network (http:// icp-forests.net/contributors). Part of the data were cofinanced by the European Commission (data downloaded on October 15, 2018). We further thank David Clark, John Byrne, Alan Taylor, Pete Fule, Mark Harmon, Tom Veblen, Nathan Stephenson, Adrian Das, and Phil van Mantgem for sharing forest plot data. Funding for some of the long-term forest plot data came from the US Geological Survey?s Land Change Science Program. Publisher Copyright: {\textcopyright} 2019 National Academy of Sciences. All rights reserved.",
year = "2019",
doi = "10.1073/pnas.1821387116",
language = "English (US)",
volume = "116",
pages = "24662--24667",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "49",
}