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Wood density provides new opportunities for reconstructing past temperature variability from southeastern Australian trees


O'Donnell, AJ and Allen, K and Evans, RM and Cook, ER and Trouet, V and Baker, PJ, Wood density provides new opportunities for reconstructing past temperature variability from southeastern Australian trees, Global and Planetary Change, 141 pp. 1-11. ISSN 0921-8181 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 Elsevier B.V. All rights reserved.

DOI: doi:10.1016/j.gloplacha.2016.03.010


Tree-ring based climate reconstructions have been critical for understanding past variability and recent trends in climate worldwide, but they are scarce in Australia. This is particularly the case for temperature: only one tree-ring width based temperature reconstruction based on Huon Pine trees from Mt Read, Tasmania exists for Australia. Here, we investigate whether additional tree-ring parameters derived from Athrotaxis cupressoides trees growing in the same region have potential to provide robust proxy records of past temperature variability.

We measured wood properties, including tree-ring width (TRW), mean density, mean cell wall thickness (CWT), and tracheid radial diameter (TRD) of annual growth rings in Athrotaxis cupressoides, a long-lived, high-elevation conifer in central Tasmania, Australia. Mean density and CWT were strongly and negatively correlated with summer temperatures. In contrast, the summer temperature signal in TRW was weakly positive. The strongest climate signal in any of the tree-ring parameters was maximum temperature in January (mid-summer; JanTmax) and we chose this as the target climate variable for reconstruction. The model that explained most of the variance in JanTmax was based on TRW and mean density as predictors. TRW and mean density provided complementary proxies with mean density showing greater high-frequency (inter-annual to multi-year) variability and TRW showing more low-frequency (decadal to centennial-scale) variability. The final reconstruction model is robust, explaining 55% of the variance in JanTmax, and was used to reconstruct JanTmax for the last five centuries (15302010C.E.). The reconstruction suggests that the most recent 60 years have been warmer than average in the context of the last ca. 500years. This unusually warm period is likely linked to a coincident increase in the intensity of the subtropical ridge and dominance of the positive phase of the Southern Annular Mode in summer, which weaken the influence of the band of prevailing westerly winds and storms on Tasmanian climate. Our findings indicate that wood properties, such as mean density, are likely to provide significant contributions toward the development of robust climate reconstructions in the Southern Hemisphereand thus toward an improved understanding of past climate in Australasia.

Item Details

Item Type:Refereed Article
Keywords:cell wall thickness, SilviScan, Southern Annular Mode, subtropical ridge, Tasmania, tree-ring width
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Palaeoclimatology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Allen, K (Dr Kathy Allen)
ID Code:142993
Year Published:2016
Web of Science® Times Cited:13
Deposited By:Geography and Spatial Science
Deposited On:2021-02-19
Last Modified:2021-11-24

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