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Ra isotopes in trees: Their application to the estimation of heartwood growth rates and tree ages

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dc.contributor Dept Earth Sci
dc.contributor Univ Melbourne
dc.contributor Dept Civil & Environm Engn
dc.contributor Australian Inst Marine Sci
dc.contributor Riso Natl Lab
dc.contributor Nord Lab Luminescence Dating
dc.contributor Australian Institute Of Marine Science
dc.contributor Aarhus Univ
dc.contributor Commonwealth Scientific & Industrial Research Organisation (csiro)
dc.contributor Csiro Land & Water
dc.contributor Technical University Of Denmark
dc.contributor Aarhus University
dc.contributor University Of Melbourne
dc.contributor Australian Institute Of Marine Science (aims) en ARGENT, ROBERT M. HANCOCK, GARY J. BRUNSKILL, GREGG J. MURRAY, ANDREW S. 2017-03-21T00:53:07Z 2017-03-21T00:53:07Z 2013-02-28T06:44:48Z 2019-07-08T02:24:55Z 2013-02-28T06:44:48Z 2013-02-28T06:44:48Z 2017-03-21T00:53:07Z 2019-07-08T02:24:55Z 2006-11-10
dc.identifier 7372 en
dc.identifier.citation Hancock GJ, Murray AS, Brunskill GJ and Argent R (2006) Ra isotopes in trees: their application to the estimation of heartwood growth rates and tree ages. Global Biogeochemical Cycles. 20: GB4007. en
dc.identifier.issn 0886-6236
dc.description Link to abstract/full text - en
dc.description.abstract The difficulty in estimating growth rates and ages of tropical and warm-temperate tree species is well known. However, this information has many important environmental applications, including the proper management of native forests and calculating uptake and release of atmospheric carbon. We report the activities of Ra isotopes in the heartwood, sapwood and leaves of six tree species, and use the radial distribution of the Ra-228/Ra-226 activity ratio in the stem of the tree to estimate the rate of accretion of heartwood. A model is presented in which dissolved Ra in groundwater is taken up by tree roots, translocated to sapwood in a chemically mobile (ion-exchangeable) form, and rendered immobile as it is transferred to heartwood. Uptake of Th-232 and Th-230 (the parents of Ra-228 and Ra-226) is negligible. The rate of heartwood accretion is determined from the radioactive decay of Ra-228 (half-life 5.8 years) relative to long-lived Ra-226 (half-life 1600 years), and is relevant to growth periods of up to 50 years. By extrapolating the heartwood accretion rate to the entire tree ring record the method also appears to provide realistic estimates of tree age. Eight trees were studied (three of known age, 72, 66 and 35 years), including three Australian hardwood eucalypt species, two mangrove species, and a softwood pine (P. radiata). The method indicates that the rate of growth ring formation is species and climate dependent, varying from 0.7 rings yr(-1) for a river red gum (E. camaldulensis) to around 3 rings yr(-1) for a tropical mangrove (X. mekongensis).
dc.description.uri en
dc.language English
dc.language en en
dc.relation.ispartof Null
dc.relation.ispartof Global Biogeochemical Cycles - pages: 20: GB4007 en
dc.subject Deposition
dc.subject Mangrove Tree
dc.subject Rainfall
dc.subject Australia
dc.subject Environmental Sciences & Ecology
dc.subject Forests
dc.subject Environmental Sciences
dc.subject Radium
dc.subject Meteorology & Atmospheric Sciences
dc.subject Geosciences, Multidisciplinary
dc.subject Ratios
dc.subject Carbon
dc.subject Tropical Trees
dc.subject Geology
dc.subject Rings
dc.title Ra isotopes in trees: Their application to the estimation of heartwood growth rates and tree ages
dc.type journal article en
dc.identifier.doi 10.1029/2005GB002641
dc.identifier.wos WOS:000241984000001

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