Informing climate models with rapid chamber measurements of forest carbon uptake

Research output: Contribution to journalArticle

Abstract

Models predicting ecosystem carbon dioxide (CO2) exchange under future climate change rely on relatively few real-world tests of their assumptions and outputs. Here, we demonstrate a rapid and cost-effective method to estimate CO2 exchange from intact vegetation patches under varying atmospheric CO2 concentrations. We find that net ecosystem CO2 uptake (NEE) in a boreal forest rose linearly by 4.7 ± 0.2% of the current ambient rate for every 10 ppm CO2 increase, with no detectable influence of foliar biomass, season, or nitrogen (N) fertilization. The lack of any clear short-term NEE response to fertilization in such an N-limited system is inconsistent with the instantaneous downregulation of photosynthesis formalized in many global models. Incorporating an alternative mechanism with considerable empirical support – diversion of excess carbon to storage compounds – into an existing earth system model brings the model output into closer agreement with our field measurements. A global simulation incorporating this modified model reduces a long-standing mismatch between the modeled and observed seasonal amplitude of atmospheric CO2. Wider application of this chamber approach would provide critical data needed to further improve modeled projections of biosphere–atmosphere CO2 exchange in a changing climate.

Details

Authors
  • Daniel B. Metcalfe
  • Daniel Ricciuto
  • Sari Palmroth
  • Catherine Campbell
  • Vaughan Hurry
  • Jiafu Mao
  • Sonja G. Keel
  • Sune Linder
  • Xiaoying Shi
  • Torgny Näsholm
  • Klas E.A. Ohlsson
  • M. Blackburn
  • Peter E. Thornton
  • Ram Oren
Organisations
External organisations
  • Oak Ridge National Laboratory
  • Duke University
  • Swedish University of Agricultural Sciences, Umeå
  • Agroscope
  • Swedish University of Agricultural Sciences
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Environmental Sciences

Keywords

  • boreal forest, earth system model, model-data integration, nutrient limitation, photosynthetic downregulation, Pinus sylvestris
Original languageEnglish
Pages (from-to)2130-2139
Number of pages10
JournalGlobal Change Biology
Volume23
Issue number5
Publication statusPublished - 2017 May 1
Publication categoryResearch
Peer-reviewedYes