Whole-tree chambers for elevated atmospheric CO<inf>2</inf> experimentation and tree scale flux measurements in south-eastern Australia: The Hawkesbury Forest Experiment

Barton, CVM; Ellsworth, DS; Medlyn, BE; Duursma, RA; Tissue, DT; Adams, MA; Eamus, D; Conroy, JP; McMurtrie, RE; Parsby, J; Linder, S

Whole-tree chambers for elevated atmospheric CO<inf>2</inf> experimentation and tree scale flux measurements in south-eastern Australia: The Hawkesbury Forest Experiment

Barton, CVM Ellsworth, DS Medlyn, BE Duursma, RA Tissue, DT Adams, MA Eamus, D

Conroy, JP McMurtrie, RE Parsby, J Linder, S

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Publication Type:: Journal Article
Citation:: Agricultural and Forest Meteorology, 2010, 150 (7-8), pp. 941 - 951
Issue Date:: 2010-07-01

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Field	Value	Language
dc.contributor.author	Barton, CVM	en_US
dc.contributor.author	Ellsworth, DS	en_US
dc.contributor.author	Medlyn, BE	en_US
dc.contributor.author	Duursma, RA	en_US
dc.contributor.author	Tissue, DT	en_US
dc.contributor.author	Adams, MA	en_US
dc.contributor.author	Eamus, D https://orcid.org/0000-0003-2765-8040	en_US
dc.contributor.author	Conroy, JP	en_US
dc.contributor.author	McMurtrie, RE	en_US
dc.contributor.author	Parsby, J	en_US
dc.contributor.author	Linder, S	en_US
dc.date.issued	2010-07-01	en_US
dc.identifier.citation	Agricultural and Forest Meteorology, 2010, 150 (7-8), pp. 941 - 951	en_US
dc.identifier.issn	0168-1923	en_US
dc.identifier.uri	http://hdl.handle.net/10453/13435
dc.description.abstract	Resolving ecophysiological processes in elevated atmospheric CO2 (Ca) at scales larger than single leaves poses significant challenges. Here, we describe a field-based experimental system designed to grow trees up to 9m tall in elevated Ca with the capacity to control air temperature and simultaneously measure whole-tree gas exchange. In western Sydney, Australia, we established the Hawkesbury Forest Experiment (HFE) where we built whole-tree chambers (WTC) to measure whole-tree CO2 and water fluxes of an evergreen broadleaf tree, Eucalyptus saligna. A single E. saligna tree was grown from seedling to small tree within each of 12 WTCs; six WTCs were maintained at ambient Ca and six WTCs were maintained at elevated Ca, targeted at ambient Ca +240μmolmol-1. All 12 WTCs were controlled to track ambient outside air temperature (Tair) and air water vapour deficit (Dair). During the experimental period, Tair, Dair and Ca in the WTCs were within 0.5°C, 0.3kPa, and 15μmolmol-1 of the set-points for 90% of the time, respectively. Diurnal responses of whole-tree CO2 and water vapour fluxes are analysed, demonstrating the ability of the tree chamber system to measure rapid environmental responses of these fluxes of entire trees. The light response of CO2 uptake for entire trees showed a clear diurnal hysteresis, attributed to stomatal closure at high Dair. Tree scale CO2 fluxes confirm the hypothesised deleterious effect of chilling night-time temperatures on whole-tree carbon gain in this subtropical Eucalyptus. The whole-tree chamber flux data add an invaluable scale to measurements in both ambient and elevated Ca and allow us to elucidate the mechanisms driving tree productivity responses to elevated Ca in interaction with water availability and temperature. © 2010 Elsevier B.V.	en_US
dc.relation.ispartof	Agricultural and Forest Meteorology	en_US
dc.relation.isbasedon	10.1016/j.agrformet.2010.03.001	en_US
dc.subject.classification	Meteorology & Atmospheric Sciences	en_US
dc.title	Whole-tree chambers for elevated atmospheric CO<inf>2</inf> experimentation and tree scale flux measurements in south-eastern Australia: The Hawkesbury Forest Experiment	en_US
dc.type	Journal Article
utslib.citation.volume	7-8	en_US
utslib.citation.volume	150	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0502 Environmental Science and Management	en_US
utslib.for	04 Earth Sciences	en_US
utslib.for	06 Biological Sciences	en_US
utslib.for	07 Agricultural and Veterinary Sciences	en_US
dc.location.activity	ISI:000280077500008	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	open_access
pubs.issue	7-8	en_US
pubs.publication-status	Published	en_US
pubs.volume	150	en_US

Abstract:

Resolving ecophysiological processes in elevated atmospheric CO2 (Ca) at scales larger than single leaves poses significant challenges. Here, we describe a field-based experimental system designed to grow trees up to 9m tall in elevated Ca with the capacity to control air temperature and simultaneously measure whole-tree gas exchange. In western Sydney, Australia, we established the Hawkesbury Forest Experiment (HFE) where we built whole-tree chambers (WTC) to measure whole-tree CO2 and water fluxes of an evergreen broadleaf tree, Eucalyptus saligna. A single E. saligna tree was grown from seedling to small tree within each of 12 WTCs; six WTCs were maintained at ambient Ca and six WTCs were maintained at elevated Ca, targeted at ambient Ca +240μmolmol-1. All 12 WTCs were controlled to track ambient outside air temperature (Tair) and air water vapour deficit (Dair). During the experimental period, Tair, Dair and Ca in the WTCs were within 0.5°C, 0.3kPa, and 15μmolmol-1 of the set-points for 90% of the time, respectively. Diurnal responses of whole-tree CO2 and water vapour fluxes are analysed, demonstrating the ability of the tree chamber system to measure rapid environmental responses of these fluxes of entire trees. The light response of CO2 uptake for entire trees showed a clear diurnal hysteresis, attributed to stomatal closure at high Dair. Tree scale CO2 fluxes confirm the hypothesised deleterious effect of chilling night-time temperatures on whole-tree carbon gain in this subtropical Eucalyptus. The whole-tree chamber flux data add an invaluable scale to measurements in both ambient and elevated Ca and allow us to elucidate the mechanisms driving tree productivity responses to elevated Ca in interaction with water availability and temperature. © 2010 Elsevier B.V.

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http://hdl.handle.net/10453/13435