'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.
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