Mainland Australia’s alpine ash forests face a shrinking regeneration window as high-severity fires overlap more frequently than the species can tolerate, with the shift in fire regimes now driving federal protection under the country’s primary environment law.
That is according to Tom Fairman, a forest and fire scientist at the University of Melbourne who has studied fire regimes in Victorian alpine ash country for more than a decade, and who said the species is being squeezed by a fire frequency it evolved to withstand only at much longer intervals.
“We’re shifting from infrequent severe fires to probably more frequent severe fires, and that’s where you really have this issue for the forest type,” Dr Fairman told ABC Rural, explaining that high-severity burns — defined in the conservation advice as greater than 90 per cent leaf scorch — cause close to 100 per cent tree mortality across affected stands.
Burnt alpine ash drops seed in the months following fire, but the resulting cohort requires 15 to 20 years before it can flower and set the next generation, a regeneration gap that collapses when two high-severity fires strike the same stand inside that window.
“The real risk to alpine ash is when large fires start overlapping one another,” Dr Fairman said, warning that repeated burns eliminate the species from affected stands entirely and strip the landscape of what defines the forest type.
The Department of Climate Change, Energy, the Environment and Water formally added alpine ash forests across the ACT, NSW and Victoria to the national threatened ecological community list on 20 March, citing altered fire regimes driven by climate change as the primary threat. Areas occupied by the species experienced substantially more fires between 2001 and 2020 than during the previous two decades, according to the approved conservation advice.
Alpine ash forests also provide critical habitat for Leadbeater’s possum and the greater glider — both species already facing acute population pressure — and hold cultural significance for First Nations communities across the high country, factors cited in the conservation advice alongside the fire regime findings.
The listing has drawn sharp criticism from the Australian Forest Products Association, with AFPA chief executive Diana Hallam telling ABC Rural the decision “absolutely astounded” the sector and overlooks the fact that logging is already banned in nearly all alpine ash forests across the three jurisdictions.
“The future of the ash forests depends on active management, including seed collection and prescribed burning, amongst other activities,” Hallam said, characterising the federal decision as a lock-and-leave approach that would do nothing to protect the species.
Meanwhile, Timber Towns Victoria, the community group representing 11 local councils that depend on forests, argued that the listing rests on environmental ideology rather than on evidence of what actually threatens the high-country stands:
“These forests face real and immediate threats from excessive fuel loads and repeated wildfire,” according to Karen Stephens, Glenelg mayor and president of Timber Towns Victoria. “This listing actually leads to less management, not more, and will do nothing to protect them.”
Dr Fairman said the listing alone would not arrest the trajectory of mainland alpine ash, and that proactive testing of new management approaches — before the next cycle of overlapping high-severity fires — would determine whether the species regenerates across its current range or contracts sharply over the coming 15 to 20 years.
