A STUDY of Victoria's Black Saturday bushfires has found the risk zone between houses and forests is much larger than authorities say.
Houses up to one kilometre away from large forest areas are at risk of wildfire, according to new research from the University of Wollongong.
But the study authors say the one-kilometre risk zone is at odds with Australian fire management authorities, who state the risk zone is between 25-500m, varying from state to state.
The results have prompted the researchers to call for risk strategies advanced by authorities to be revised.
"The zone of one kilometre around houses is very large and requires a rethink of bushfire risk strategies," study co-author Dr Owen Price says.
The study looked at the 2009 Victorian bushfires which were the worst in Australia's history, claiming 173 lives and causing more than $4 billion in damage.
Using statistical modelling, a sample of 3500 houses affected in the fires was studied looking at how much forest around houses affected the likelihood they would be destroyed.
Researchers found houses surrounded by a large proportion of forest within a kilometre were at risk, even if trees were not near the house.
Houses were also more likely to be destroyed if there were other houses within 50m and if they were on a slope.
Dr Price says previous studies have already shown hazard reduction burns have little effect during catastrophic fire conditions.
He says residents who are surrounded by forest should look at fireproofing their homes.
"Because the main threats seem to be from embers and house to house transmission, hardening houses to fire is another obvious way that risk could be reduced," he says.
Risk strategies could also be revised to include increasing setbacks between houses and forest in new developments, he says.
The study results are published in scientific journal PLOS ONE.
Originally published as Bushfire risk needs rethink: study