10 years on, rainforest not recovered from Black Saturday fires

Victorian Department of Environment research has found that the O’Shannassy Catchment’s cool temperate rainforest burnt in the 2009 Black Saturday bushfires has not recovered and the survival of Australian rainforests against climate projections “appears bleak”.

Despite rainforest species having some documented resistance to fire, Arn Tolsma and colleagues from the Arthur Rylah Institute for Environmental Research found that the primary rainforest species in the catchment, Myrtle Beech and Southern Sassafras, have been unable to fend off incursion from other non-rainforest species, particularly eucalypt Mountain Ash and wattle species.

Two-thirds of cool temperate rainforest mapped in the O’Shannassy Catchment before the fire, can no longer be classified as such. Of the most severely burnt parts of these mapped areas, 96% of cool temperate rainforest was lost.

“Our findings are not ‘new’… they are consistent with what other researchers are finding, that is, that fires seem to be getting bigger and hotter, overwhelming the capacity of rainforests to cope,” says Arn.In the O’Shannassy catchment, Mountain Ash seedlings have been “converting the burnt rainforest into a mixed and more flammable forest of Mountain Ash over rainforest.”

In Northern NSW, rainforest ecologist, Robert Kooyman, has been monitoring the aftermath of the recent summer bushfires on the Gondwana Rainforest, and is alarmed by the germination trends of mountain wattle. He too, anticipates that factors relevant to the fatality of Victorian rainforest, climate change and logging, will play out there in the years to come.

“It's about the major shift in vegetation type," says Robert. "Trees are modular units, they’re capable of resprouting from the root or base of a tree, but that doesn’t mean they’re resilient to fire or that those resprouts will survive. Some of these trees are hundreds of years old. It could take years before we see that tree die.”