Impacts of forest age on water use in Mountain ash forests

Functional Plant Biology
By: , and 

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Abstract

Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire  returning to pre-fire levels in the following centuries  owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8mmday-1 with increasing forest age (an annual decrease of 657mm) the understorey ET contributed between 1.2 and 1.5mmday-1, 45% of the total ET (3mmday-1) at the old growth forest.

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Publication type Article
Publication Subtype Journal Article
Title Impacts of forest age on water use in Mountain ash forests
Series title Functional Plant Biology
DOI 10.1071/FP08120
Volume 35
Year Published 2008
Language English
Publisher CSIRO
Contributing office(s) Coop Res Unit Leetown
Description 9 p.
First page 483
Last page 492
Country Australia
Online Only (Y/N) N
Additional Online Files (Y/N) N
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