03 August, 2014

Study finds logging increased intensity of Black Saturday fires

James Campbell
HeraldsunAugust 03, 2014

A study has found logging in the decades prior to Black Saturday made the deadly blaze much more ­extreme.

THE heat and severity of Kinglake and Marysville fires that killed 159 people on Black Saturday was significantly increased by clear-fell logging of forests, scientists believe.

In a landmark two-year study of the Kilmore East and Murrindindi Mill fires, which destroyed Marysville and ­severely damaged Kinglake, scientists from Melbourne University and the ANU examined satellite images of hundreds of thousands of trees burnt on Black Saturday.

The scientists say the study showed conclusively that logging in the decades prior to Black Saturday made the deadly blaze much more ­extreme.

They also warn that increased fire danger in forests lasts for up to 70 years after an area is logged, with the risk peaking between 10 and 50 years.

The findings of the study will have implications for the bushfire risk to towns such as Warburton and Healesville, which are close to logging operations.

Professor David Lindenmayer, Australia’s leading scientist of forest ecology, who headed the study said it showed conclusively that clear fell logging increased the danger from bushfire.

“Our findings show the severity of the fires on Black Saturday was significantly higher in the areas that had been logged,” he said.

Professor Lindenmayer said preliminary estimates suggested the fire was 25 per cent more severe in forest that had been logged than in old-growth forest.

“This added severity is sufficient to kill people and add significantly to property and forest damage,” he said.

Prof Lindenmayer said the increased fire risk had strong implications for towns close to forestry operations such as Healesville, Powelltown, Warburton and Noojee as well as towns such as Woodend that were close to areas logged in earlier decades.

“Industrial clear felling of ash forests should not take place close to any human settlement,” he said.

The scientists believe the increased fire risk in logged areas is due to several factors.

Regrowth forests have more trees packed more closely together and contain large amounts of flash fuels allowing fire to build in severity, the study found.

Old-growth forests usually have wet rainforest under­storey canopies, which do not burn as well as the drier understorey canopies of regrowth forests.

In the past 50 years, more than 47,000 ha of wet forest have been logged with 17,600 ha to be logged in the next five years.

The Kilmore East and Murrindindi fires, which later merged, were the most deadly on Black Saturday, collectively killing 159 people , destroying 1780 homes and burning 168,542 ha.

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