'Ash forests’ – forest comprised of Mountain Ash, Alpine Ash, or sometimes both – are some of the most iconic forest types in Victoria, or even the world. Covering around 500,000 ha of Victoria and stretching from the Otways to the north-eastern boundary with NSW, few who spend time in these forests – like driving along the Black Spur north-east of Melbourne - are left unimpressed by these tall trees. They are also home to species like the Leadbeater’s Possum and Greater Glider.
These forests have a complex relationship with fire: these forests can live with some fire - but not too much. Scientifically known as ‘obligate seeders’, after severe bushfire, ash forests are killed, but prolifically regenerates from canopy stored seed. The important point here is that these slowly regenerating forests cannot produce seed for 20 years after they regenerate from fire. This means they are highly vulnerable to shortened fire intervals – the exact challenge that land managers in Victoria are facing with climate change.
Once a mountain ash or alpine ash forest has burnt numerous times, it may eventually fail to regenerate, which can lead to population collapse and a change of ecosystem type. This sounds simple, but ecologically, this is dramatic. A tall forest – high in carbon stocks and habitat – changes rapidly to a short shrubland or grassland.
This not theory. This situation already exists among alpine ash forests. The massive bushfires in 1998, 2003, 2006, 2009, 2013, 2014 and 2019/20 and meant that over 97% of Alpine Ash distribution burnt. These fires overlapped and some areas burnt two to three times across two decades (Fagg et al. 2013; Bassett et al. 2021), leaving 43,000 ha of Alpine Ash forest at risk of collapse (Fairman, 2023).
This challenge will also persist as a problem for future land managers. At present it is estimated that there is about 140,000 ha of vulnerable (young) ash regrowth in the state that will not self-regenerate if burnt. This ‘at risk’ area will reduce to about 80,000 ha in 2024, as older regrowth matures – but still presents a massive risk for land managers.
ABOVE: burnt Alpine Ash forests near Mt Hotham.
What can the Victorian government do?
The challenge described above is not news to the Victorian Government – there have been many programs over the last two decades which have acted to recover ash forest impacted by multiple fires, but the issue is how well these programs are resourced in the future.
Simply, ash forests at risk of regeneration failure can be ‘saved’ by the sowing of seed from helicopters immediately following the bushfires if we have sufficient supplies of seed available.
The Victorian Government has a long history of doing this. After the 2013 fires in the Upper
Ovens valley (the Harrietville-Alpine fire), the Victorian government established the Ash Forest Restoration Project which collected and then aerially seeded ash forests which were facing population collapse after those fires. This action was required again in 2019, then in 2020. The 2020 Ash Restoration program was the largest in Victorian history – an estimated 30,000 ha of ash was at risk of regeneration failure, and needed aerial reseeding. Due to a lack of stored seed, 10,000 ha could be seeded, leaving 20,000 ha to collapse (Bassett et al. 2021).
The Ash Forest Restoration Program is therefore a significant and necessary program, with management currently shared by a number of agencies including VicForests. Once VicForests is wound up, management of the Ash program should be taken over entirely by DEECA and funding for this program must be maintained and extended.
The Post-bushfire Forest Recovery group needs to be expanded within DEECA (there are currently only 2 staff located in the north east).
Additionally funding is required to sustain roles in ash seed collection. We understand that funding for this work has ceased, or is close to ending. The Black Summer fires demonstrated the wisdom of having large stores of ash seed available. However it also exhausted seed supply. We understand that DEECA has collected about 6 tonnes of Ash seed post 2020 bushfire however we need at least 20 tonnes to be able to respond to bad fire seasons that are likely to occur over the next few summers.
As well as collecting seed, it is crucial that forecasting of future seed production is understood. This can only be done through monitoring of flowering in ash forests. To maximise seed collection opportunities, it is essential that the ‘Floral and Seed Forecasting Project’ – the crucial base-work on which the forest recovery program sits – is maintained. There are a series of 26 strategically located sites for floral and seed development monitoring across Victoria’s Great Divide, plus annual mapping of flowering crops using aerial flowering assessments. This helps identify areas where seed will not exist at the time of a fire (and therefore need to be sowed if fire occurs). This gives land managers confidence about natural recovery where seed is known to be in mature forests, and identifies collection sites to build the state’s strategic seed bank for future post-fire forest recovery. This work is in jeopardy as funding ended in June 2023 with uncertainty of further support. This work is sometimes funded through VicForests (with funds ultimately coming from DEECA), but funding should now directly occur through DEECA.
A new, specific and imminent risk has recently been confirmed through the Floral and Seed Forecasting Project. Seed crops in the canopy of Ash forests are currently critically low; particularly for Mountain Ash (Eucalyptus regnans), and are at levels so low that not even mature Ash has capacity to self-recover should a bushfire occur in the next two seasons (23/24 and 24/25). Seed availability will return during early 2025, and Forest Solutions recommends that priority be given to collecting seed of that species during 2025. Following that, priority be given to collecting Alpine Ash (E. delegatensis) seed in 2026.
ABOVE: logged and burnt ash forests that have failed to regenerate. Dargo High Plains.
- Once VicForests is wound up, management of the Ash program should be taken over entirely by DEECA
- Funding for this program – specifically including seed collection - must be maintained and extended and recognised as an essential ongoing business activity of the Department
- The Post-bushfire Forest Recovery group needs to be expanded within DEECA and considered as a permanent, business-as-usual activity rather than an emergency response team
- Ensure funding for the Floral and Seed Forecasting Project
- Continue collecting Alpine Ash seed from the few sporadic locations it currently exists in
- Prioritise Mountain Ash seed collection exclusively in 2025, starting February. Prioritise Alpine Ash seed collection in 2026, with a continuation of Mountain Ash collecting.
Bassett, O.D., Prior, L.D., Slijkerman, C., Jamieson, D. and Bowman, M.J.S. (2015) Aerial sowing stopped the loss of Alpine Ash (Eucalyptus delegatensis) forests burnt by three short-interval fires in the Alpine National Park, Victoria, Australia. Journal of Ecology and Forest Management 342; 39-48.
Bassett, O.D., Galey, B., Hansby, M., and Paterson, C. (2021) Post-fire Forest Recovery – 2020. The recovery of Ash forests burnt during Victoria’s 2019/20 Black Summer bushfires, with recommendations for silvicultural intervention and advice regarding forest type-change. Report by Forest Solutions for the Department of Environment, Land, Water and Planning, Victoria.
Fagg, P., Lutze, M., Slijkerman, C., Ryan, M., Bassett, O., (2013). Silvicultural recovery in Ash forests following three recent large bushfires in Victoria. Australian Forestry 76, 140-155.
Fairman, T. (2023) A Strategic Assessment of Ash Forest Immaturity Risk. Report by University of Melbourne to Department of Environment, Land, Water & Planning.
ABOVE: healthy Alpine Ash forest near Mt Wills.