A STUDY by forestry experts from Melbourne University and the Australian National University has found no evidence that timber harvesting made the 2019-20 bushfires in east Gippsland and New South Wales larger and more severe.
The study, led by professors Rod Keenan from Melbourne and Peter Kanowski from the ANU, appeared last month in the publication Australian Forestry.
It follows another recent earlier report led by professors David Bowman (University of Tasmania) and Ross Bradstock (University of Wollongong) that produced a similar conclusion.
Professor Keenan was also a contributor to this paper.
The latter study found that fire weather was the biggest cause of the massive fires, which resulted in 44 per cent of the native forests suffering severe canopy damage.
“Past logging and wildfire disturbance in natural forests had a very low effect on severe canopy damage, reflecting the limited extent logged in the last 25 years (4.5 per cent in eastern Victoria, 5.3 per cent in southern New South Wales and 7.8 per cent in northern NSW),” the study concluded.
The 2019-20 bushfires burnt 5.8 million hectares of forest in Victoria and NSW, with 1.8 million ha suffering high severity burns.
A total of 33 people died and more than 3000 homes were destroyed.
The Melbourne-ANU study said some argued that the severity and extent of the fires was made worse by timber harvesting and associated forest management, and that harvesting should cease to reduce fire risk.
“Little evidence has been presented to support these contentions,” according to the study, which analysed these claims in some depth.
The authors said log production from native forests had declined by 50 per cent in the past 20 years, while the average annual area burnt had more than doubled.
A transition to plantation timber production had been underway for 30 years, but had had little impact on fire extent or severity.
“Long-undisturbed old-growth forests are also proving highly vulnerable to the impacts of landscape-scale fires,” the authors noted.
“For example, the area of old-growth forest in Victoria has declined by more than 50 per cent since 2000, with 99 per cent of this loss due to bushfires.”
The study said “the extent and severity of the burns was determined almost entirely by three years of well-below average rainfall (leading to dry fuels across all vegetation types), extreme fire weather conditions and local topography”.
Long-term, human-induced trends in climate across the region contributed to these climate extremes, increasing the chance that climate change could increase the number of large-scale fires in the future.
The ignition sources for the fires were mainly lightning strikes in remote areas.
Three major inquiries into fires – by the Commonwealth, Victoria and NSW – made no recommendations regarding the impact of timber harvesting on fire risk, the study noted.
In the Victorian government inquiry, the Inspector-General observed that “the timber industry provides an important support capacity to fire management in Victorian forests with a skill set, knowledge base and operational experience in forest landscapes”.
“The cessation of native forest harvesting by 2030 poses challenges for the fuel management program and bushfire response capacity across the state,” he said.
Professor Keenan said future forestry policy should reflect the fact that the studies showed little evidence timber harvesting contributed to the fires’ severity.
“Policy proposals to mitigate fire risks and impacts should be evidence-based and integrate multiple perspectives,” he said.
“Traditional Indigenous knowledge, experience of local and professional fire managers, and the breadth of evidence from bushfire research should inform strategies for reducing bushfire impacts and increasing forest resilience.”