Direct and indirect effects of elevated CO2 on leaf respiration in a forest ecosystem

J. G. Hamilton, R. B. Thomas, E. H. Delucia

Research output: Contribution to journalArticlepeer-review


We measured the short-term direct and long-term indirect effects of elevated CO2 on leaf dark respiration of loblolly pine (Finns taeda) and sweetgum (Liquidambar styraciflua) in an intact forest ecosystem. Trees were exposed to ambient or ambient + 200 μmol mol-1 atmospheric CO2 using free-air carbon dioxide enrichment (FACE) technology. After correcting for measurement artefacts, a short-term 200 μmol mol-1 increase in CO2 reduced leaf respiration by 7-14% for sweetgum and had essentially no effect on loblolly pine. This direct suppression of respiration was independent of the CO2 concentration under which the trees were grown. Growth under elevated CO2 did not appear to have any long-term indirect effects on leaf maintenance respiration rates or the response of respiration to changes in temperature (Q10, R0). Also, we found no relationship between mass-based respiration rates and leaf total nitrogen concentrations. Leaf construction costs were unaffected by growth CO2 concentration, although leaf construction respiration decreased at elevated CO2 in both species for leaves at the top of the canopy. We conclude that elevated CO2 has little effect on leaf tissue respiration, and that the influence of elevated CO2 on plant respiratory carbon flux is primarily through increased biomass.

Original languageEnglish (US)
Pages (from-to)975-982
Number of pages8
JournalPlant, Cell and Environment
Issue number9
StatePublished - 2001


  • Free-air carbon dioxide enrichment (FACE)
  • Liquidambar styraciflua
  • Loblolly pine
  • Pinus taeda
  • Sweetgum

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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