Global review highlights wildfire risk management strategies

A recent study published in Natural Hazard reviewed guidelines on creating defensible space to reduce wildfire risk around homes in wildland and rural urban interfaces.

The research, conducted by Ondei, Price, and Bowman, emphasized that defensible space helps reduce house loss and provides a safe area for residents and firefighters to defend properties during wildfires.

Guidelines from various regions, including Africa, Europe, North America, South America, and Oceania, were examined.

The study proposed a conceptual model to mitigate fire attack mechanisms through recommended approaches such as fuel type management, reduction of fuel amount, and spatial distribution.

Key recommendations include reducing or removing all fuels, especially dead plant material, within 1.5 meters of a house, minimizing fuel connectivity within 10 meters, and managing on-ground fuel in the outer part of the garden (10-30 meters).

Scientific support for defensible space design elements

Evidence from scientific literature broadly supports the defensible space design elements recommended in the guidelines.

Post-fire assessments revealed that garden characteristics significantly affect house survival during wildfires.

Effective defensible spaces are categorized into three zones: Fuel-free zone (within 1.5 meters), Open zone (1.5-10 meters), and Tree zone (10-30 meters).

These zones focus on minimizing horizontal and vertical fuel connectivity and managing vegetation to provide canopy shielding from ember attack and radiant energy.

Further empirical and modeling research is needed to identify optimal zonation around houses and understand how garden structure, species composition, and moisture status affect the risk of ignition from embers, radiant heat, and flames.

Implementation challenges and recommendations

While guidelines are available, their implementation presents challenges.

Recommendations include thinning vegetation, removing dead plant material, and selecting low-flammability species.

However, the variability in guidelines across regions suggests a need for more standardized, evidence-based recommendations.

Additionally, the use of non-flammable materials for ground cover and fencing is emphasized to reduce garden flammability.

The study also highlighted the importance of irrigation and the potential use of sprinklers in defensible spaces, although their effectiveness depends on proper installation and maintenance.

Ensuring compliance with these guidelines, particularly in high-risk areas, requires community engagement and possibly legal enforcement to achieve better wildfire risk management.

Future research directions

The study calls for more research on the effectiveness of specific defensible space zones and their characteristics.

There is also a need to explore the impact of garden biodiversity on fire risk and the potential benefits of wildlife-friendly gardens.

Understanding the social acceptability and economic feasibility of maintaining defensible spaces is crucial for encouraging community adoption of these practices.

Ongoing interdisciplinary research into defensible space is essential for developing more fire-adapted communities and promoting sustainable coexistence with wildfires.

Reducing wildfire risk through garden design: Summary

A study published in Natural Hazard reviewed international guidelines on creating defensible space to reduce wildfire risk.

Key recommendations include managing fuel types, amounts, and spatial distribution around homes.

Evidence supports these design elements, though further research is needed to optimize zonation and understand the impact of garden structures.

Implementation challenges highlight the need for standardized guidelines and community engagement.

Future research should focus on specific zone effectiveness, garden biodiversity, and social acceptance to develop fire-adapted communities.