Contrasting regional prescribed burning regimes effects the extent and impact of forest wildfire

The effectiveness of landscape prescribed burning at mitigating wildfire losses is an important but contentious issue. We used a novel meta-analysis approach to evaluate relationships between area burnt by prescribed fire, area burnt by wildfire and some wildfire losses. Our analysis included 60 years (1965–2024) of data from the public native forests of south-west Western Australia (WA), Victoria (Vic) and New South Wales (NSW). This enabled us to compare and contrast the long-term effects of mean annual prescribed burning programs of 9.2% (WA), 1.9% (Vic) and 0.7% (NSW) on total fire in the region, the proportion of the region burnt by wildfire, loss of human life and house loss. There was an inverse relationship between the proportion of the region treated with prescribed fire and the area burnt by wildfire. However, there was no relationship when the mean annual area burnt was <4%. The relatively high level of prescribed burning in WA has resulted in a substantially lower proportion of the region being burnt by wildfire and a significantly lower number of wildfire deaths and house losses. Per capita, wildfire deaths were 18 times higher in Vic and five times higher in NSW, than WA. An increase in the extent and severity of wildfire in the last two decades, especially in south-east Australia, can be primarily attributed to inadequate fuel management and a changing climate. In a warming, drying climate that is unlikely to be stabilised for many decades, it is essential to intensify fuel management near valued assets and, in the broader landscape, to ensure fewer ignitions become wildfires and to make wildfire suppression safer and more efficient. Our analysis suggests that, for forest regions, at least 5–8% should be prescribed burnt each year to reduce the area burnt by wildfire and to reduce wildfire losses.