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Frequent fires reduce tree growth in northern Australian savannas: implications for tree demography and carbon sequestration
Citation
Murphy, BP and Russell-Smith, J and Prior, LD, Frequent fires reduce tree growth in northern Australian savannas: implications for tree demography and carbon sequestration, Global Change Biology, 16, (1) pp. 331-343. ISSN 1354-1013 (2010) [Refereed Article]
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Copyright Statement
The definitive published version is available online at: http://interscience.wiley.com
Official URL: http://interscience.wiley.com
DOI: doi:10.1111/j.1365-2486.2009.01933.x
Abstract
Tropical savannas are typically highly productive yet fire-prone ecosystems, and it has
been suggested that reducing fire frequency in savannas could substantially increase the
size of the global carbon sink. However, the long-term demographic consequences of
modifying fire regimes in savannas are difficult to predict, with the effects of fire on
many parameters, such as tree growth rates, poorly understood. Over 10 years, we
examined the effects of fire frequency on the growth rates (annual increment of diameter
at breast height) of 3075 tagged trees, at 137 locations throughout the mesic savannas of
Kakadu, Nitmiluk and Litchfield National Parks, in northern Australia. Frequent fires
substantially reduced tree growth rates, with the magnitude of the effect markedly
increasing with fire severity. The highest observed frequencies of mild, moderate and
severe fires (1.0, 0.8 and 0.4 fires yr1, respectively) reduced tree growth by 24%, 40% and
66% respectively, relative to unburnt areas. These reductions in tree growth imply
reductions in the net primary productivity of trees by between 0.19 tCha1 yr1, in the
case of mild fires, and 0.51 tCha1 yr1, in the case of severe fires. Such reductions are
relatively large, given that net biome productivity (carbon sequestration potential) of
these savannas is estimated to be just 1–2 tCha1 yr1. Our results suggest that current
models of savanna tree demography, that do not account for a relationship between
severe fire frequency and tree growth rate, are likely to underestimate the long-term
negative effects of frequent severe fires on tree populations. Additionally, the negative
impact of frequent severe fires on carbon sequestration rates may have been underestimated;
reducing fire frequencies in savannas may increase carbon sequestration to a
greater extent than previously thought.
Item Details
Item Type: | Refereed Article |
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Keywords: | carbon sequestration, fire management, net primary productivity, northern Australia, tree demography, tree growth, tropical savanna |
Research Division: | Environmental Sciences |
Research Group: | Ecological applications |
Research Field: | Ecosystem function |
Objective Division: | Environmental Management |
Objective Group: | Fresh, ground and surface water systems and management |
Objective Field: | Assessment and management of freshwater ecosystems |
UTAS Author: | Murphy, BP (Dr Brett Murphy) |
UTAS Author: | Prior, LD (Dr Lynda Prior) |
ID Code: | 59938 |
Year Published: | 2010 |
Web of Science® Times Cited: | 90 |
Deposited By: | Plant Science |
Deposited On: | 2009-12-23 |
Last Modified: | 2011-05-13 |
Downloads: | 0 |
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