Extreme fire weather, topography and excess fuel loads are the main drivers of bushfire severity across Australia and have a far greater impact than sustainably managed timber harvesting, with responsible logging, stand age, and land tenure carrying only minor effects at a landscape scale. That is according to a new evidence review released by Forestry Australia, which examines the contested science behind claims that harvesting raises forest flammability and fire risk.
The review, Contested Evidence About Timber Harvesting and Bushfire Risk in Australian Landscapes, finds that the studies behind those claims analysed only clearfelling in tall wet eucalypt forests of Australia’s south, a forest type the review says represents less than 2 per cent of the country’s forested area. Their conclusions are nonetheless routinely communicated as though they apply to every forest type, despite relationships between forest age, management history, and fire severity not holding consistently across forest types.
Much of the contest in science stems from inconsistent use of fire terminology, with the review noting that fire risk, fire severity, fire intensity, and flammability carry distinct meanings and cannot be used interchangeably. Studies arguing that harvesting increases the flammability of native forests have, in fact, analysed fire severity data, not flammability, fire intensity, or fire risk data.
Forestry Australia President Michelle Freeman said the review was developed to clarify a complex and frequently misunderstood area of forest science, examining what the evidence does and does not show and where research findings remain contested. The diversity of the country’s forests meant evidence could not be applied uniformly, Freeman said, with findings from one forest type, management system or landscape context requiring careful qualification before being read nationally.
“When these terms are used interchangeably, public understanding suffers,” Freeman said.
Landscape-scale analyses of major bushfires, including the 2019-20 Black Summer fires, have found that extreme fire weather and topography are the dominant drivers of fire severity, whilst timber harvesting, stand age, and land tenure carry comparatively minor effects. Across the NSW public forest burnt in 2019-20, a greater share of protected national park was burnt at high severity than State forest available for timber production, and in Victoria, the proportions burnt at high severity in national park and in harvestable State forest were essentially the same.
Wood Central understands that the review also challenges the assumption that old-growth forests rarely burn at high severity, noting that the 2019-20 Victorian fires burnt about 40,800 hectares of old-growth forest at high severity, roughly two-thirds of which was inside conservation reserves where harvesting is excluded. Significant areas of old forest were lost the same way in 1939 and 2009, including in Melbourne’s water catchments, where timber harvesting has never been permitted.
The review concludes that the public dissemination of the idea that “logging always increases fire risk” rests on “narrow, limited and contested evidence from one forest type”, and that the problem is worsened by media reporting that incorrectly conflates terms such as risk and flammability. It also points to peer-reviewed criticism that broadcasting those site-scale findings as landscape-wide fact has been characterised as advocacy presented as scientific neutrality.
Freeman said Forestry Australia’s role was to support evidence-based discussion grounded in forest science rather than to advance simplistic arguments, and urged journalists, policy makers and community leaders to weigh the full body of evidence. Forestry Australia is an independent not-for-profit representing more than 1,150 forest scientists, managers and growers across native forests, plantations and environmental services.
