Subalpine regions struggle to recover after 2019-20 bushfires as eucalypt forests fare better

Forests in some subalpine areas near Mount Kosciuszko and in Victoria’s East Gippsland region are struggling to recover from the 2019-20 bushfires, according to researchers examining the aftermath of the disaster.

But eucalypts in forested areas of the New South Wales south coast appear to be recovering well, say the scientists, who are tracking the sites using data gathered by groups of citizen scientists.

The Bushfire Recovery Project is a team of five scientists based at Griffith and the Australian National universities.

It was formed following the catastrophic 2019-20 bushfire season – which burned more than 8m hectares – to bring together experts and community volunteers to produce data that might assist with the development of post-fire policy.

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Citizen scientists have been tracking forest regrowth on the south coast near Batemans Bay and in subalpine woodlands near the NSW and Victorian border.

Patrick Norman, an ecologist at Griffith University and one of the lead researchers, said the groups had been monitoring sites on a weekly basis, taking photos and recording information using a dedicated app.

Norman said forests on the south coast dominated by eucalypts, which were more resilient to fire, appeared to be faring well, as did some areas of East Gippsland.

“Most eucalpyt forests once a fire has gone through, even if all of the leaves have been burnt, they’ll shoot out recovery buds,” he said.

“We’re trying to take note of how they’re greening, whether or not they’re shooting from the canopy or the tree. On the south coast, they’re recovering quite well, especially when it’s larger, older forests.”

The groups have compiled hundreds of records from sites in the Murramarang and Monga national parks and sites on the western side of Mount Kosciuszko.

The scientists then use satellite data to compare the information gathered by the citizen scientists with data showing the extent to which those forests had burnt and their pre-fire condition to determine how their recovery is progressing.

David Lindenmayer, of the Australian National University, is another member of the Bushfire Recovery Project.

He said the resprouting occurring in areas along the south coast was “wonderful” but said the fires, combined with the effects of drought and logging, had taken a toll on wildlife such as the koala and greater glider.

Lindenmayer said subalpine areas in the mountain country of East Gippsland and southern NSW were not showing the same level of forest recovery.

He said the team had been monitoring communities in locations dominated by alpine ash, which regenerate by producing seeds rather than sprouting recovery buds.

When a fire comes through, seeds drop to the forest floor and germinate to produce a new stand of trees.

But Lindenmayer said frequent fires in those areas in recent years meant that trees being burnt were too young to produce seeds.

“What it means is fires are burning young trees, which means there’s no seed rain from the canopy, which is how these trees regenerate,” he said.

“It’s burning through young trees that aren’t old enough to produce seed, so the system is dead.”

Lindenmayer said there had been a huge effort in Victoria after the fires to collect seeds that could be used to re-establish forest in the worst-affected areas.

“Whilst the recovery in some parts is wonderful and is great to see, in other places I’m really concerned about how much the landscape is burning and how frequently,” he said.

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Steve Douglas is an ecologist based in NSW who has conducted extensive surveys in subalpine zones of the Kosciuszko national park over the past five years. He said he had seen the effects of previous fires, prior to the 2019-20 season, and drought on those systems.

“There were areas up there … that looked like they’d been hit by an air burst nuclear detonation. They were absolutely flatlined,” he said.

“The alps has long been flagged in climate impact models as one of the most at-risk bioregions in Australia from temperature rise, drying and increased fire frequency and intensity,” he said.

Justin Field, an independent NSW MLC and resident of the south coast, said it was a relief to see new growth in the region’s burnt forests “and the clean white trunks of big spotted gums that have now shed their burnt bark”.

“But there are also large areas where the intensity of the fires was much greater, many large trees have now clearly died and the canopy has been entirely lost,” he said.

“The recovery is going to be slow and the long-term impacts may not be known for a long time.”