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Bark thickness determines fire resistance of selected tree species from fire-prone tropical savanna in north Australia

Lawes, Michael J., Richards, Anna E., Dathe, Josefine and Midgley, Jeremy J. (2011). Bark thickness determines fire resistance of selected tree species from fire-prone tropical savanna in north Australia. Plant Ecology,212(12):2057-2069.

Document type: Journal Article

IRMA ID 82057923xPUB82
Title Bark thickness determines fire resistance of selected tree species from fire-prone tropical savanna in north Australia
Author Lawes, Michael J.
Richards, Anna E.
Dathe, Josefine
Midgley, Jeremy J.
Journal Name Plant Ecology
Publication Date 2011
Volume Number 212
Issue Number 12
ISSN 1385-0237   (check CDU catalogue  open catalogue search in new window)
Scopus ID 2-s2.0-83055172941
Start Page 2057
End Page 2069
Total Pages 13
Place of Publication Dordrecht
Publisher Springer Netherlands
HERDC Category C1 - Journal Article (DIISR)
Abstract We investigated the fire resistance conferred by bark of seven common tree species in north Australian tropical savannas. We estimated bark thermal conductance and examined the relative importance of bark thickness, density and moisture content for protecting the cambium from lethal fire temperatures. Eucalypt and non-eucalypt species were contrasted, including the fire-sensitive conifer Callitris intratropica. Cambial temperature responses to bark surface heating were measured using a modified wick-fire technique, which simulated a heat pulse comparable to surface fires of moderate intensity. Bark thickness was a better predictor of resistance to cambial injury from fires than either bark moisture or density, accounting for 68% of the deviance in maximum temperature of the cambium. The duration of heating required to kill the cambium of a tree (τ c) was directly proportional to bark thickness squared. Although species did not differ significantly in their bark thermal conductance (k), the thinner barked eucalypts nevertheless achieved similar or only slightly lower levels of fire resistance than much thicker barked non-eucalypts. Bark thickness alone cannot account for the latter and we suggest that lower bark moisture content among the eucalypts also contributes to their apparent fire resistance. Unique eucalypt meristem anatomy and epicormic structures, combined with their bark traits, probably facilitate resprouting after fire and ensure the dominance of eucalypts in fire-prone savannas. This study emphasises the need to take into account both the thermal properties of bark and the mechanism of bud protection in characterising the resprouting ability of savanna trees.
Keywords bark density
bark thermal conductance
cambium
resprouting
topkill
DOI http://dx.doi.org/10.1007/s11258-011-9954-7   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
 
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Created: Fri, 29 Aug 2014, 17:04:32 CST by Anthony Hornby