With the changing plant make up of the rural–urban interface and more Australians choosing to live in these areas, how can we improve our understanding of extreme fire behaviours in fragmented interface fuels to reduce risks and protect communities?
The Natural Hazards Research Australia-funded (the Centre) Bushfire risk at the rural–urban interface project provides new insights, practical tools and policy recommendations to help communities better manage bushfire risk at the rural–urban interface (RUI).
In the May Hazardous Webinar, researchers Prof David Bowman and Dr Grant Williamson from the University of Tasmania and end-user Melissa O’Halloran from the New South Wales Rural Fire Service discussed one of Australia's most pressing bushfire challenges: protecting lives and property where communities meet flammable landscapes.
Project lead Prof Bowman framed the research against what he described as a growing global fire crisis. Recent international analysis shows an increase in large, costly and destructive fire disasters around the world, highlighting the urgent need for long-term, sustainable approaches to bushfire risk management.
To address this challenge, the team developed a research program built around three interconnected themes: geospatial, biophysical, and social. The project examined house-loss patterns in Australia and the United States, fuel management options, garden fire hazards, plant flammability, community attitudes towards fuel treatments, risk perceptions and evacuation intentions.
Understanding risk beyond the 100-metre rule
One of the project's key findings was that the commonly used 100-metre planning rule remains a useful indicator of bushfire risk but may not capture the full extent of hazard under extreme fire weather conditions.
Research led by the geospatial team found that the likelihood of house loss can increase significantly at distances approaching one kilometre from flammable vegetation during catastrophic fire weather. The team also identified the potential for urban conflagrations – where fire spreads through suburban areas – under certain conditions, reinforcing the need for broader approaches to risk assessment.
Prof Bowman highlighted the importance of defendable space around homes, particularly the role of gardens in determining vulnerability.
The research suggests greater emphasis should be placed on maintaining a fuel-free zone within one to two metres of buildings, alongside thoughtful garden design, vegetation management and irrigation.
Rethinking fuel management strategies
The project also explored fuel management options around towns and cities.
The research team investigated forest thinning, prescribed burning and vegetation management, finding that no single treatment is suitable across all environments. Thinning has the potential to reduce fuel loads but can generate large quantities of residual debris that create additional management challenges. Prescribed burning can reduce risk, but its effectiveness is often limited in duration and varies according to vegetation type and site conditions.
The findings suggest future fuel management strategies are likely to require a customised mix of treatments tailored to local circumstances.
New tools for assessing bushfire risk
Dr Grant Williamson, Deputy Director of the Fire Centre at the University of Tasmania, presented several practical tools developed through the project.
A key output is a garden hazard assessment system that evaluates risk around homes across three zones and provides advice for risk reduction. The assessment considers factors such as vegetation structure, garden connectivity, barriers and maintenance practices.
Importantly, the research found that overall garden design is often more important than the flammability of individual plant species. Well-designed gardens with reduced fuel connectivity, effective barriers and good maintenance can help lower risk, even when some potentially flammable plants are present.
Researchers also demonstrated how LiDAR data can be used to assess many garden-risk characteristics remotely. This creates opportunities to rapidly identify higher-risk properties at neighbourhood and suburb scales, helping agencies prioritise engagement and mitigation efforts.
At the landscape scale, the team developed new ember transport and radiant heat modelling tools that can map bushfire hazard across communities and test the effectiveness of risk-reduction scenarios. Modelling undertaken in Hobart showed that combining fuel treatments with modifications to high-risk interface areas could substantially reduce the number of homes exposed to bushfire hazards.
Social insights to support community preparedness
The social research component revealed several important challenges for emergency management agencies.
Surveys found ongoing confusion about concepts such as places of last resort and nearby safer places, as well as uncertainty around evacuation decisions. Researchers also found that community attitudes towards fuel treatment methods can be influenced by political beliefs, highlighting the importance of carefully designed communication and engagement strategies.
The research identified opportunities to improve preparedness through personalised risk information, community mentoring, practical assistance programs, green waste removal services and support for residents with physical limitations. A key finding was that residents often have strong emotional connections to their gardens, meaning hazard reduction initiatives must balance safety outcomes with community values.
Supporting future bushfire management
Melissa O'Halloran, Manager of Bushfire Risk Planning at the NSW Rural Fire Service, reflected on the project's value from an end-user perspective.
She said the research addressed longstanding questions about house-loss patterns identified during the devastating 2019–20 Black Summer bushfire season and provided a more sophisticated understanding of risk at the rural–urban interface.
Ms O'Halloran highlighted the potential of the LiDAR-based garden assessment approach to support future bushfire risk management planning, helping agencies prioritise on-ground engagement and evaluate the effectiveness of mitigation activities over time.
The project's findings are already informing policy discussions and future planning initiatives, and the research provides a strong foundation for future work aimed at building safer, more resilient communities in an increasingly challenging bushfire environment.