Burnoffs useless in slowing fire: ACF
Burnoffs useless in slowing fire: ACF
10 September 2009
published by www.theaustralian.news.com.au
Australia — The Australian Conservation Foundation has told the Black Saturday royal commission that prescribed burning does little or nothing to slow fires during extreme conditions such as those on February 7.
In a submission sure to reignite the debate between pro- and anti-burning groups, the ACF and other conservation groups say bushfire science shows areas that have been burnt off ignite just as quickly as unburnt forest during such megafires.
The groups are using the submission in an attempt to say prescribed burning is not a “silver bullet” and efforts to prevent bushfire losses and damage need to focus on fire warnings and communications systems.
Forest Fire Victoria, an alliance calling for a tripling in the amount of prescribed burning in Victoria, described the ACF submission’s claims as “nonsense”.
FFV president Athol Hodgson, a former chief fire officer of Victoria, told The Australian: “Just to make a bald statement that, over a certain fuel level, prescribed burning does not work is stupid. It’s nonsense.
“In my view it downgrades the importance of prescribed burning.
“If there’s no fuel, there’s no fire. You can’t do much about weather or drought, but you can do something about fuel.”
FFV hopes the commission will recommend the prescribed burning target be increased from 130,000ha to the 385,000ha-a-year target recommended by a parliamentary committee but not implemented by the Victorian government.
However, the groups who commissioned the bushfire science report by RMIT sustainability researcher and PhD candidate Chris Taylor — including the Wilderness Society and the Victorian National Parks Association — said it aimed to put prescribed burning into context as a fire management tool.
The Wilderness Society’s Richard Hughes said: “Vegetation clearance, including firebreaks, will not prevent the spread of fires under catastrophic weather conditions and should only be considered as one part of a broader fire management strategy.”
Mr Taylor’s report uses a formula produced by leading University of Melbourne fire researcher Kevin Tolhurst that tracks the effectiveness of prescribed burns in slowing fires as conditions worsen and the forest fire danger index (FFDI) increases.
Mr Taylor extrapolated the formula, which previously stopped at an FFDI of 100, to cover FFDIs up to 200, such as existed on Black Saturday. He found “the probability of previous prescribed burns slowing a head fire significantly decreased with increasing FFDI” and that at 200 it had practically no effect.
He said yesterday areas of previously burnt forest hit during Black Saturday suffered just as severe damage as areas of virgin forest that had not been burnt.
Mr Tolhurst, who was working with fire authorities at the emergency co-ordination centre during Black Saturday, said the extrapolation of the formula was valid in that burns had little effect in slowing fires on catastrophic days. But he said such extreme conditions occurred only for about 26 hours every two months, and the rest of the time prescribed burns were an effective fire mitigation tool.
“It would be quite dangerous to extrapolate from that and say that prescribed burning is not useful,” Mr Tolhurst said.
