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Unusual Southern Hemisphere tree growth patterns induced by changes in the Southern Annular Mode


Villalba, R and Lara, A and Masiokas, MH and Urrutia, R and Luckman, BH and Marshall, GJ and Mundo, IA and Christie, DA and Cook, ER and Neukom, R and Allen, K and Fenwick, P and Boninsegna, JA and Srur, AM and Morales, MS and Araneo, D and Palmer, JG and Cuq, E and Aravena, JC and Holz, A and Lequesne, C, Unusual Southern Hemisphere tree growth patterns induced by changes in the Southern Annular Mode, Nature Geoscience, 5, (11) pp. 793-798. ISSN 1752-0894 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Macmillan Publishers Limited

DOI: doi:10.1038/ngeo1613


Recent changes in the summer climate of the Southern Hemisphere extra-tropics are primarily related to the dominance of the positive phase of the Southern Annular Mode. This shift in the behaviour of the Southern Annular Mode - essentially a measure of the pressure gradient between Southern Hemisphere mid and high latitudes - has been predominantly induced by polar stratospheric ozone depletion. The concomitant southward expansion of the dry subtropical belts could have consequences for forest growth. Here, we use tree-ring records from over 3,000 trees in South America, Tasmania and New Zealand to identify dominant patterns of tree growth in recent centuries. We show that the foremost patterns of growth between 1950 and 2000 differed significantly from those in the previous 250 years. Specifically, growth was higher than the long-term average in the subalpine forests of Tasmania and New Zealand, but lower in the dry-mesic forests of Patagonia. We further demonstrate that variations in the Southern Annular Mode can explain 12-48% of the tree growth anomalies in the latter half of the twentieth century. Tree-ring-based reconstructions of summer Southern Annular Mode indices suggest that the high frequency of the positive phase since the 1950s is unprecedented in the past 600 years. We propose that changes in the Southern Annular Mode have significantly altered tree growth patterns in the Southern Hemisphere.

Item Details

Item Type:Refereed Article
Keywords:climate change, ozone hole, tree rings, temperate forests
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Allen, K (Dr Kathy Allen)
UTAS Author:Holz, A (Dr Andres Holz)
ID Code:82986
Year Published:2012
Web of Science® Times Cited:170
Deposited By:Plant Science
Deposited On:2013-02-26
Last Modified:2021-05-04

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