An analysis of the sensitivity of sap flux to soil and plant variables assessed for an Australian woodland using a soil-plant-atmosphere model

Melanie Zeppel, Catriona MacInnis-Ng, Anthony Palmer, Daniel Taylor, Rhys Whitley, Sigfredo Fuentes, Isa Yunusa, Mathew Williams, Derek Eamus

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Daily and seasonal patterns of tree water use were measured for the two dominant tree species, Angophora bakeri E.C.Hall (narrow-leaved apple) and Eucalyptus sclerophylla (Blakely) L.A.S. Johnson & Blaxell (scribbly gum), in a temperate, open, evergreen woodland using sap flow sensors, along with information about soil, leaf, tree and micro-climatological variables. The aims of this work were to (a) validate a soil-plant-atmosphere (SPA) model for the specific site; (b) determine the total depth from which water uptake must occur to achieve the observed rates of tree sap flow; (c) examine whether the water content of the upper soil profile was a significant determinant of daily rates of sap flow; and (d) examine the sensitivity of sap flow to several biotic factors. It was found that (a) the SPA model was able to accurately replicate the hourly, daily and seasonal patterns of sap flow; (b) water uptake must have occurred from depths of up to 3 m; (c) sap flow was independent of the water content of the top 80 cm of the soil profile; and (d) sap flow was very sensitive to the leaf area of the stand, whole tree hydraulic conductance and the critical water potential of the leaves, but insensitive to stem capacitance and increases in root biomass. These results are important to future studies of the regulation of vegetation water use, landscape-scale behaviour of vegetation, and to water resource managers, because they allow testing of large-scale management options without the need for large-scale manipulations of vegetation cover.

Original languageEnglish
Pages (from-to)509-520
Number of pages12
JournalFunctional Plant Biology
Volume35
Issue number6
DOIs
Publication statusPublished - 2008
Externally publishedYes

Bibliographical note

Corrigendum can be found in Functional Plant Biology, Volume 36(12), 1120,
http://dx.doi.org/10.1071/FP08114_CO

Keywords

  • Hydraulic conductance
  • Narrow-leaved apple
  • Scribbly gum
  • Soil moisture
  • Transpiration

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