Role of forest regrowth in global carbon sink dynamics

Research output: Contribution to journalArticle

Abstract

Although the existence of a large carbon sink in terrestrial ecosystems is well-established, the drivers of this sink remain uncertain. It has been suggested that perturbations to forest demography caused by past land-use change, management, and natural disturbances may be causing a large component of current carbon uptake. Here we use a global compilation of forest age observations, combined with a terrestrial biosphere model with explicit modeling of forest regrowth, to partition the global forest carbon sink between old-growth and regrowth stands over the period 1981–2010. For 2001–2010 we find a carbon sink of 0.85 (0.66–0.96) Pg year −1 located in intact old-growth forest, primarily in the moist tropics and boreal Siberia, and 1.30 (1.03–1.96) Pg year −1 located in stands regrowing after past disturbance. Approaching half of the sink in regrowth stands would have occurred from demographic changes alone, in the absence of other environmental changes. These age-constrained results show consistency with those simulated using an ensemble of demographically-enabled terrestrial biosphere models following an independent reconstruction of historical land use and management. We estimate that forests will accumulate an additional 69 (44–131) Pg C in live biomass from changes in demography alone if natural disturbances, wood harvest, and reforestation continue at rates comparable to those during 1981–2010. Our results confirm that it is not possible to understand the current global terrestrial carbon sink without accounting for the size-able sink due to forest demography. They also imply that a large portion of the current terrestrial carbon sink is strictly transient in nature.

Details

Authors
Organisations
External organisations
  • University of Birmingham
  • Western Sydney University
  • Montana State University
  • NASA Goddard Space Flight Center
  • Karlsruhe Institute of Technology
  • CSIRO Oceans and Atmosphere, Canberra
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Geography

Keywords

  • Carbon sink, Demography, Disturbance, Forest, Regrowth
Original languageEnglish
Pages (from-to)4382-4387
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume116
Issue number10
Publication statusPublished - 2019
Publication categoryResearch
Peer-reviewedYes