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.
It is tragic that fires are so frequent and intense that we face the prospect of seeing these vegetation communities collapse. There are many ways we must respond: acting decisively on climate change, and protecting these forests from wildfire and over logging. Aerial seeding programs also aim to help these forests survive.
According to a 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.
Previous periods of high frequency fires (e.g. fires in 1926 and 1939 at Lake Mountain in Victoria) caused the conversion of E. delegatensis forest to Acacia obliquinervia shrubland. The scale of the current vegetation type conversion appears to be historically unprecedented, driven by recent warming and drying, which is projected to continue with ongoing climate change.’
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.
This is not ‘new’ news. For instance, areas within the Harrietville fire boundary in 2013 have been burnt several times over the past decade and Department of Environment and Primary Industries and Parks Victoria ecology experts predict about 2,000 hectares will not be able to naturally regenerate due to the nature of Alpine Ash and its response to fire when it becomes so frequent.
And it is the same story with Mountain Ash.
Climate change and extreme fragmentation of habitat is driving Mountain Ash forest in south-eastern Australia towards ‘almost certain collapse in the next 50 years’, according to an assessment by researchers from the ANU.
The key message in this research is:
Researchers “modelled 39 different scenarios and found there was a 92 to 99.99% chance of collapse of the mountain ash forest in Victoria’s Central Highlands by 2067”.
Direct seeding efforts in Victoria
It is clear that we will need to intervene to ensure both these species survive. In some instances this will involve direct seeding. But how does this actually happen? This radio interview, featuring Owen Bassett, of Forest Solutions, which is based in north east Victoria, outlines work being carried out to reseed burnt Ash forests. It originally aired on the Living on Earth program from PRX.
From the story:
“With no intervention, these ravaged forests, located primarily in Southeast Australia, would eventually turn into a different type of ecosystem, like savanna or grassland. Owen Bassett, of Forest Solutions, is not ready to let that happen. For years, he has collected seeds from these trees and manually replanted them in an effort to rebuild the forest”.
“Like Mountain Ash, Alpine Ash are “obligate seeders — that is, they can regenerate after fire only from seed and not from their trunks — “if we have enough seed and we have the means to spread that seed where the forest is going to experience population collapse, then we can intervene, lay seed on the ground, and these forests will return,” Bassett explained. “But it’s easier said than done. We have to collect the seed and we have to distribute the seed, and that’s a mammoth operation.”
He explains how the seed is gathered:
“Bassett has been monitoring the flowering of these species for 26 years. Every year, he maps the distribution of their flowering from a light aircraft, he explained. Once trees have flowered, he marks their location in the landscape. One year later, he can expect these trees will have seed.
At that point, Forest Solutions sends teams of climbers in to scale the 262-foot tall trees and de-limb about a third of the branches on them. “We keep the tree healthy; we keep the growing tip in place,” Bassett said. “We take just a section of that crown out and from that, we can pick the seed pods. They’re sent away and the seeds are extracted from … those pods.”
The seeds are tiny, about the size of coarse pepper, Basset added. “It’s extraordinary to think that such a tall tree, something akin to California redwoods, comes from this tiny piece of cracked pepper-size seed.”
Reseeding requires about a pound per acre, Bassett said. The seed is put in a hopper inside a helicopter and spun out the bottom of the aircraft as it flies. The swathe of seed is only 20 meters wide — about 60 feet”.
He also says that we need government support for these initiatives.
“Bassett has been pressing Australia’s federal government for years to establish a seed bank, but it has only funded small seed collection operations in reaction to fire outbreaks, rather than gather seed steadily and store it away.
“We needed 10 tonnes of seed this year,” Bassett said. That’s the equivalent of about 22,000 pounds of seeds. “At the moment, we might have a third, maybe a half, of that. … It’s very frustrating. But, at this stage, we battle on.”
In May 2020, Forest Fire Management Victoria announced that:
‘Communities in fire affected areas near Walwa and some fire affected parts of East Gippsland may see helicopters flying low over forested areas this weekend and in the coming weeks, as part of a $3 million Mountain and Alpine Ash reseeding project.
Department of Environment, Land, Water and Planning (DELWP) is preparing to reseed nearly 13,000 hectares of public land impacted by the fires. Reseeding works will focus 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.
Mountain and Alpine Ash forests are important ecosystems that support a wide range of Victoria’s wildlife and Victoria’s sub-alpine biodiversity’.