Measured and modelled leaf and stand-scale productivity across a soil moisture gradient and a severe drought

J. K. Wright*, M. Williams, G. Starr, J. Mcgee, R. J. Mitchell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Environmental controls on carbon dynamics operate at a range of interacting scales from the leaf to landscape. The key questions of this study addressed the influence of water and nitrogen (N) availability on Pinus palustris (Mill.) physiology and primary productivity across leaf and canopy scales, linking the soil-plant-atmosphere (SPA) model to leaf and stand-scale flux and leaf trait/canopy data. We present previously unreported ecophysiological parameters (e.g. Vcmax and Jmax) for P. palustris and the first modelled estimates of its annual gross primary productivity (GPP) across xeric and mesic sites and under extreme drought. Annual mesic site P. palustris GPP was similar to 23% greater than at the xeric site. However, at the leaf level, xeric trees had higher net photosynthetic rates, and water and light use efficiency. At the canopy scale, GPP was limited by light interception (canopy level), but co-limited by nitrogen and water at the leaf level. Contrary to expectations, the impacts of an intense growing season drought were greater at the mesic site. Modelling indicated a 10% greater decrease in mesic GPP compared with the xeric site. Xeric P. palustris trees exhibited drought-tolerant behaviour that contrasted with mesic trees' drought-avoidance behaviour.

Original languageEnglish
Pages (from-to)467-483
Number of pages17
JournalPlant, Cell and Environment
Volume36
Issue number2
DOIs
Publication statusPublished - Feb 2013

Keywords

  • eddy-covariance
  • GPP
  • leaf area index
  • photosynthesis
  • soil moisture
  • SPA model
  • LONGLEAF PINE
  • STOMATAL CONDUCTANCE
  • PHOTOSYNTHETIC PARAMETERS
  • HYDRAULIC ARCHITECTURE
  • UNCERTAINTY ANALYSIS
  • WIREGRASS SAVANNAS
  • ECOSYSTEM FUNCTION
  • EDDY COVARIANCE
  • PONDEROSA PINE
  • USE EFFICIENCY

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