Dry season conditions determine wet season water use in the wet-dry tropical savannas of northern Australia

Eamus, D; O'Grady, AP; Hutley, L

Dry season conditions determine wet season water use in the wet-dry tropical savannas of northern Australia

Eamus, D

O'Grady, AP Hutley, L

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Publication Type:: Journal Article
Citation:: Tree Physiology, 2000, 20 (18), pp. 1219 - 1226
Issue Date:: 2000-01-01

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Field	Value	Language
dc.contributor.author	Eamus, D https://orcid.org/0000-0003-2765-8040	en_US
dc.contributor.author	O'Grady, AP	en_US
dc.contributor.author	Hutley, L	en_US
dc.date.issued	2000-01-01	en_US
dc.identifier.citation	Tree Physiology, 2000, 20 (18), pp. 1219 - 1226	en_US
dc.identifier.issn	0829-318X	en_US
dc.identifier.uri	http://hdl.handle.net/10453/13432
dc.description.abstract	Daily and seasonal patterns of transpiration were measured in evergreen eucalypt trees growing at a wet (Darwin), intermediate (Katherine) and dry site (Newcastle Waters) along a steep rainfall gradient in a north Australian savanna. Relationships between tree size and tree water use were also determined. Diameter at breast height (DBH) was an excellent predictor of sapwood area in the five eucalypt species sampled along the rainfall gradient. A single relationship existed for all species at all sites. Mean daily water use was also correlated to DBH in both wet and dry seasons. There were no significant differences in the relationship between DBH and tree water use at Darwin or Katherine. Among the sites, tree water use was lowest at Newcastle Waters at all DBHs. The relationship between DBH and tree leaf area was similar between species and locations, but the slope of the relationship was less at the end of the dry season than at the end of the wet season at all locations. There was a strong relationship between sapwood area and leaf area that was similar at all sites along the gradient. Transpiration rates were significantly lower in trees at the driest site than at the other sites, but there were no significant differences in transpiration rates between trees growing at Darwin and Katherine. Transpiration rates did not vary significantly between seasons at any site. At all sites, there was only a 10% decline in water use per tree between the wet and dry seasons. A monthly aridity index (pan evaporation/rainfall) and predawn leaf water potential showed strong seasonal patterns. It is proposed that dry season conditions exert control on tree water use during the wet season, possibly through an effect on xylem structure.	en_US
dc.relation.ispartof	Tree Physiology	en_US
dc.relation.isbasedon	10.1093/treephys/20.18.1219	en_US
dc.subject.classification	Plant Biology & Botany	en_US
dc.title	Dry season conditions determine wet season water use in the wet-dry tropical savannas of northern Australia	en_US
dc.type	Journal Article
utslib.citation.volume	18	en_US
utslib.citation.volume	20	en_US
utslib.for	0705 Forestry Sciences	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0607 Plant Biology	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	18	en_US
pubs.publication-status	Published	en_US
pubs.volume	20	en_US

Abstract:

Daily and seasonal patterns of transpiration were measured in evergreen eucalypt trees growing at a wet (Darwin), intermediate (Katherine) and dry site (Newcastle Waters) along a steep rainfall gradient in a north Australian savanna. Relationships between tree size and tree water use were also determined. Diameter at breast height (DBH) was an excellent predictor of sapwood area in the five eucalypt species sampled along the rainfall gradient. A single relationship existed for all species at all sites. Mean daily water use was also correlated to DBH in both wet and dry seasons. There were no significant differences in the relationship between DBH and tree water use at Darwin or Katherine. Among the sites, tree water use was lowest at Newcastle Waters at all DBHs. The relationship between DBH and tree leaf area was similar between species and locations, but the slope of the relationship was less at the end of the dry season than at the end of the wet season at all locations. There was a strong relationship between sapwood area and leaf area that was similar at all sites along the gradient. Transpiration rates were significantly lower in trees at the driest site than at the other sites, but there were no significant differences in transpiration rates between trees growing at Darwin and Katherine. Transpiration rates did not vary significantly between seasons at any site. At all sites, there was only a 10% decline in water use per tree between the wet and dry seasons. A monthly aridity index (pan evaporation/rainfall) and predawn leaf water potential showed strong seasonal patterns. It is proposed that dry season conditions exert control on tree water use during the wet season, possibly through an effect on xylem structure.

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http://hdl.handle.net/10453/13432