Fires and hydrology of north eastern mixed-species forests

This study examined the eco-hydrology of mixed-species eucalypt forests as they regenerate after crown-removing fires, such as the 2009 Black Saturday fires. The investigation was based on broad management questions: How much water is used by trees after fire? How much water goes into catchments? Is the quality of this water fit for use in towns and cities?

The research was conducted by the University of Sydney’s Dr Tina Bell and Dr Tarryn Turnbull, who found that the water use by vegetation in mixed-species eucalypt forests did not increase markedly during the recovery phase following intense fire.

This is a significant finding, as it means it is unlikely that water yields from mixed-species catchments will be as strongly affected by fire as water yields from forests comprised of Ash-type eucalypts, where much previous research has been conducted.

A key difference between the mixed-species forests and the Ash-type forests is that the trees in mixed-species forests mostly resprout after fire, while the Ash-type forests are killed and regrow from seed.

The findings from this project can be used by catchment land planners and water supply authorities to find optimal strategies for simultaneously managing fire and ensuring water supply continuity. The results are directly applicable to the mixed-species catchments in south eastern Australia.

Outside of south eastern Australia, catchment managers may be able to build on this work and have the vegetation water use models validated for new ecosystems. The work may also be useful at a strategic level to inform water policy.

The effect of bushfire on Sydney’s water catchments was investigated in a PhD study from Jessica Heath (University of Sydney). Her work showed that the pre‐bushfire models used had predicted the post‐bushfire models well, and that bushfire had no obvious effect on water yield within the Sydney drinking water supply catchments.
 

Related news

Research has helped measure erosion following bushfires
What has been learned about how fire affects water supply, carbon emissions and smoke?
Quantifying the impact of fire on tree water use
Do mixed species eucalyptus forests use more water as they recover from fire?
The panel sessions were a popular addition to the forum program
More than 75 researchers, end users, PhD students, land managers and industry representatives attended the seventh Bushfire CRC Research Advisory Forum on 23-24 October, held at the NSW Rural Fire Service headquarters in Sydney.
Fire in the landscape - Tarryn Turnbull
A group of fire managers and scientists this month went deep into the forests of north east Victoria to view research sites.
The Bushfire CRC is leading a Fire in the Landscape field excursion as part of its professional development event series, on Tuesday 27 March 2012.

External References

Jessica Heath is conducting a PhD study with the Bushfire CRC at the University of Sydney on the impacts of wildfire on the water supply catchments of the Sydney Basin.

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