Field-based tree mortality constraint reduces estimates of model-projected forest carbon sinks

Kailiang Yu, Philippe Ciais, Sonia I. Seneviratne, Zhihua Liu, Han Y.H. Chen, Jonathan Barichivich, Craig D. Allen, Hui Yang, Yuanyuan Huang, Ashley P. Ballantyne

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Considerable uncertainty and debate exist in projecting the future capacity of forests to sequester atmospheric CO2. Here we estimate spatially explicit patterns of biomass loss by tree mortality (LOSS) from largely unmanaged forest plots to constrain projected (2015–2099) net primary productivity (NPP), heterotrophic respiration (HR) and net carbon sink in six dynamic global vegetation models (DGVMs) across continents. This approach relies on a strong relationship among LOSS, NPP, and HR at continental or biome scales. The DGVMs overestimated historical LOSS, particularly in tropical regions and eastern North America by as much as 5 Mg ha−1 y−1. The modeled spread of DGVM-projected NPP and HR uncertainties was substantially reduced in tropical regions after incorporating the field-based mortality constraint. The observation-constrained models show a decrease in the tropical forest carbon sink by the end of the century, particularly across South America (from 2 to 1.4 PgC y−1), and an increase in the sink in North America (from 0.8 to 1.1 PgC y−1). These results highlight the feasibility of using forest demographic data to empirically constrain forest carbon sink projections and the potential overestimation of projected tropical forest carbon sinks.

Original languageEnglish
Article number2094
JournalNature Communications
Volume13
Issue number1
DOIs
StatePublished - Dec 2022

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