The Tasmanian eucalypt tree Brett Mifsud is about to climb is more than 500 years old, roughly 22 metres in diameter, and pushing nearly 75 metres tall.
In sheer volume alone — at over 300 cubic metres — this mountain ash is one of the largest trees in Australia.
In terms of flowering plants, it is one of the largest on Earth.
But Mr Mifsud fears this tree, along with a handful of others that remain in Tasmania's south-west, could be the last generation of giant trees in the country.
Their biggest risk? Fire.
More frequent, intense fires threaten old growth
Based in regional Victoria, Mr Mifsud has been travelling to south-west Tasmania for nearly 30 years to find, document, and measure the size and health of these giant trees.
Although laser technology is commonly used to do this, Mr Mifsud's process often involves a cheaper alternative — climbing the trees with a measuring tape.
Mr Mifsud returned to the state in November as part of a research project to investigate the threat-level that fire poses to the remaining giants and what can be done to protect them.
He said fire had typically been rare in wet forests.
"It might occur every 50, 100, 200, or, in the case of these trees, 500 years," he said.
However, drier, hotter summers, coupled with less frequent rain events and more frequent incidences of dry lightning, have changed that.
Mr Mifsud estimated that 17 of the largest trees in Australia — all mountain ash, and all found in Tasmania — were destroyed by bushfires that tore through the state's south-west in 2019.
Mountain ash – or eucalyptus regnans – are found across Tasmania and Victoria and can grow more than 100 metres tall.
Victoria has three times as many mountain ash as Tasmania, but none that compare in height or volume to Tasmania's.
Wet forests dry out
Mr Mifsud said on his last visit in late 2023 he could already spot indications the landscape was drier than usual.
And the weather bureau's spring summary confirmed that, with Tasmania's spring rainfall 33 per cent below average.
"Everything should be still damp from springtime and winter, and it's dry, it's crinkly – we could almost have a fire here," he said.
Like many Australian native trees, the mountain ash is reliant on fire to germinate its seeds, but it can't be too frequent or intense.
In the Styx Valley, where it commonly grows, evidence of infrequent fires can be found.
There are fewer young mountain ash clamouring for daylight, and thick, woody adults — many over 300-years-old — poke above the tree line.
The last time widespread fires reached the south-west was 2019, but Mr Mifsud believes the next serious bushfire is not far away.
"If fires are too frequent, for instance, if there's a fire every 10 years and the new crop can't get to maturity, this species can actually disappear from that particular landscape," he said.
'Time for slogans is ending'
Professor David Bowman, a fire scientist at the University of Tasmania and a co-author to Mr Mifsud's research, said Tasmania was globally significant for its giant trees.
"We are now responsible for some of the biggest plants on Earth," Professor Bowman said.
"It's almost like the people who were alive when the thylacines, the Tasmanian tigers, were winking out."
In Tasmania, forestry and forest conservation are topics mired in ideology and politics — and have stirred enough animosity to become etched in many memories as the "forestry wars".
However, Professor Bowman believed a practical solution can be found.
"We've got to stop this endless sloganeering. The time for slogans is ending, this is actually an emergency," he said.
"We have an opportunity to save these things, and also to develop a plan for the conservation of the next generation of giant trees."
Professor Bowman envisioned a management plan between the federal and state governments, Parks and Wildlife, and Sustainable Timber Tasmania, to identify the remaining giant trees and develop a proactive fire management plan.
"That doesn't fit with the slogan 'end forestry now' — it's reform native forestry in regrowth forests, conserve giant trees, reclassify what a giant tree is," he said.
Sights on US for mitigation, planning
Professor Bowman has turned to the US, another global epicentre for giant trees, to provide a template for a management plan.
In a bid to protect its giant sequoias from fire — with an estimated 20 per cent perishing from fire since 2021 — the Californian government has enacted an emergency plan that bypasses environmental reviews in order to remove fuel loads and low-lying vegetation from giant tree groves.
The emergency intervention also includes wrapping the base of giant trees in foil when there is heightened fire risk, and removing nearby trees that could spread fire.
In Australia, giant trees are also considered a natural asset worth protecting, but what constitutes a "giant" tree depends on where you are, and who you are talking to.
For most of Tasmania's history there was not a working definition.
In the late 1990s, Sustainable Timber Tasmania (STT) — then known as Forestry Tasmania — introduced a policy to protect any tree more than 85 metres tall.
It then introduced provisions to protect any tree greater than 280 cubic metres, and since 2016 has committed to not clear fell any logging coupes containing more than 25 per cent mapped old growth.
Based on this criteria, Mr Mifsud estimated there were about 15 giant trees left measuring more than 280 cubic metres, and about 75 trees higher than 85 metres tall.
But based on his own definition of what makes a giant tree, there are 115 trees greater than 200 cubic metres, and 40 trees higher than 87 metres tall.
Giant trees 'prioritised'
Most giant trees are found in STT's Permanent Timber Production Zone, and on land managed by the Tasmania Parks and Wildlife Service (PWS).
A PWS spokesperson said the agency prioritised "protection of identified giant trees when possible", and in the past, measures like sprinkler systems had been set up to protect ancient vegetation.
Those measures included "prioritising the area to keep fire out of the broader region and rapid attack to reduce intensity" of the blaze.
"If a fire becomes close to identified giant trees, PWS will work to reduce fuels from around the base of the trees, wetting trees down and, when safe to do so, ensure firefighters are present to protect trees," the spokesperson said.
Professor Bowman said he feared without a more proactive plan, it may not be enough to save the remaining giants.
For Mr Mifsud, the incentive to protect the trees was simple.
"Just to be humbled, to be awed — it's a wonderful thing to look up and to be dwarfed by something this big," he said.