The Bushfire Recovery Project, led by five scientists, is tracking forest regrowth in NSW and Victoria after last summer’s fires, using data gathered by citizen scientists.
Their report has found that while low elevation forests on the NSW south coast appear to be recovering well, forests in some subalpine areas ‘near Mount Kosciuszko and in Victoria’s East Gippsland region are struggling to recover from the 2019-20 bushfires’.
This is consistent with everything we already know about the impact of climate driven fire seasons on the higher elevation Alpine Ash forests and Snow Gum woodlands.
Lisa Cox, reporting in The Guardian says
‘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’.
They looked at sites on the western side of Mount Kosciuszko. One of the team members, David 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.
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.
Alpine Ash faces possible community collapse
There is no doubt that our fire seasons are getting longer and more intense and this is starting to have potentially landscape changing impacts. There is concern that Alpine Ash forests could be wiped out in some areas where fire comes in multiple waves before the recovering trees can set seed. Parts of north eastern Victoria have been burnt three times in a decade. Mountain Ash forests face similar threats.
According to research published in a report called ‘Biological responses to the press and pulse of climate trends and extreme events’, alpine ash forests face collapse.
The report (from 2018) notes:
‘Since the beginning of the 21st century a series of very large, high severity landscape fires ignited by dry lightning storms have occurred throughout the Australian Alps. These fires have killed swaths of E. delegatensis forest and initiated regeneration. However, large areas of regeneration have been reburnt, in some cases twice, causing population declines or local extinction.
An increased frequency of extreme events can also lead to population collapse if the population does not have sufficient time to recover before the event recurs. Multiple wildfires in short succession, resulting from increased dangerous fire weather, have resulted in localized conversion of obligate seeder Eucalyptus delegatensis forest to shrubland in the Australian Alps, a process that potentially threatens the entire species’ range’.
The problem is that Alpine Ash need around 20 years to reach reproductive maturity, so if fires happen more frequently than this, local extinction is possible because there is no seed stock to create a new forest.
Further information on Alpine Ash and post fire collapse available here.
Government’s have had to intervene to avoid these forest communities collapsing. In Victoria, DELWP has been reseeding more than 13,000 hectares of public land impacted by fires. Previous reseeding works has focused on areas that have been previously burnt by fires in 2003, 2007 and 2014.
Many of these forest areas are not old enough to regenerate naturally, and need this seed collection and sowing project to ensure their survival.
The situation is worse after the 219/20 fire season.
There are extensive stands of alpine ash in the mountains of eastern Victoria, and much of this was burnt last summer. After the fires, one industry rep suggested that “about 10,000 ha of Ash is at imminent population collapse in Victoria”. The company involved in the reseeding efforts noted that it had flown 70,000 ha of impacted Ash to assess the impacts and identify priority areas for reseeding.
And it’s the same for Snow Gum forests
Over 90% of the Victorian distribution of snow gums has been burned at least once since 2003. Each of the large fires of the last 15 years has overlapped to some extent, leaving thousands of hectares of snow gums burned by wildfire twice, and sometimes three times.
Keeping fire out may be the solution in snow gum forests
One significant piece of research that should inform our understanding about fire on snow gum forests looked at the impacts of fires on Lake Mountain and the Buffalo Plateau. The report How snow gum forests and sub-alpine peatlands recover after fire was written by Fiona Coates, Philip Cullen, Heidi Zimmer, James Shannon. They used the long unburnt Baw Baw Plateau as an example of what these systems could be like in the absence of fire events.
They found that:
- Even areas that have been subjected to hot and very destructive wildfire, such as on the Lake Mountain plateau during the 2009 Black Saturday fires, can be expected to recover – provided we can keep fires out of these systems. However, this will take time. For instance they suggest it will take the forests at Lake Mountain at least 70 years to return to pre-fire structure. No specific management needs to be undertaken to aid this process beyond excluding fires.
- The researchers repeatedly note that there are serious doubts about the value of fuel reduction burning in these forests. They note that low intensity fires negatively impact on tree resprouting ability.