It’s a striking image; in a suburban landscape where nature has been largely pushed aside to make way for roads, houses and driveways, the thick craggy trunk of a towering river red gum tree stands defiantly in place, forcing the bitumen to squeeze and buckle around it. Bang in the middle of the street.
Barely a day goes by without the residents of Overbury Drive noticing a carload of tourists or curious locals pulling up in their quiet cul-de-sac, cameras at the ready.
Photos of the tree, over 20 metres tall and more than 200 years old by some estimates, regularly go viral online. An unofficial Google Maps listing for the “Sacred Tree” guides visitors to this otherwise unremarkable Adelaide backstreet.
At sunset, its silhouette seems to radiate gold light as rainbow lorikeets screech and swoop around its branches. Their nests are hard to spot from the road – high up above the parked cars, wheelie bins and powerlines, the tree’s vast canopy could be its own little world.
“The tree is basically why I moved here,” says Paolo Rossi, who has lived on Overbury Drive for two years.
The 36-year-old architect’s first-floor flat looks out over the tree, allowing Rossi and his Italian greyhound Fifi to glimpse a history that predates the establishment of the South Australian state itself. “It’s so powerful as a living monument to something a bit ancient,” he says.
“For me, it’s amazing to look out my window and see this thing that has been around before any of this existed.”
But in recent years, his sense of awe turned into concern.
First, he started to spot drying and dying leaves. Then its branches, some between two to three metres long, started to die back. With each week he would see another limb begin to turn.
“I tried not to make eye contact with it for maybe the last six months – I thought, ‘Wow, this tree has been around for hundreds of years, imagine if it died on my watch?’ Then it started dying.”
When the tree first sprouted, forests of tall red gums just like it lined water courses around what we now call Adelaide. The Adelaide Plains were home to fields of kangaroo grass and copses of wattle, mallee and sheoak. The land was so carefully maintained through fire-burning by generations of Kaurna people that when settlers did eventually arrived, some compared it to an English park.
Today, the suburb of Clarence Park bears little resemblance to that precolonial landscape, and the red gum might have disappeared too if not for an unusual legal intervention.
The official story is that when Gertrude Overbury, an 85-year-old farmer’s widow who once owned the surrounding land died in 1943, her will stipulated the tree be protected in the inevitable event the property be carved up and subdivided.
Stefan Caddy-Retalic, an adjunct senior lecturer at the University of Adelaide’s Waite Arboretum, says in earlier centuries these river red gums would grow deep tap roots that accessed subterranean aquifers, and lateral roots that soaked up surface rainfall. But the neighbourhood has undergone a radical transformation since the red gum first took root.
“Imagine that you’re a gum tree,” he says. “Then a city starts to grow up around you, so some of your lateral roots are pruned because there’s a trench put in for a road, or someone puts in slab for a house, or stormwater drain or NBN conduit.
“You lose a lot of your ability to harvest rain, and then you add in a drying climate, and that means you’re not getting as much rain as you used to.”
While cities grow more inhospitable to these old giants, another cycle soon sets in: as trees and fields are replaced by steel roofs and asphalt roads that absorb heat during the day and re-radiate it at night.
“Overnight, the city doesn’t cool down, it stays hot, and that means more moisture is being lost in the soil. So we lose the shade impact, we lose the evaporative cooling benefit, and we also lose the habitat benefit for biodiversity.”
Cities around the world have increasingly been paying attention to the benefits of urban canopy beyond even the mitigation of the “urban heat island” effect; research suggests urban trees can improve sound quality, boost cortisol levels in walkers and reduce flooding risks.
But the protection of urban canopies has been a contentious issue for local and state governments around Australia. While “leafy suburb” has grown synonymous with desirability and affluence, established trees are often viewed as an inconvenience, a safety risk and an impediment to development. And while some councils give away seedlings of native trees to residents in an effort to boost the urban canopy, established trees are felled en masse – both legally and illegally. A 2021 study found greater Adelaide alone lost 75,000 trees a year.
“People expect trees in their environment, but they don’t want to be responsible for them,” Caddy-Retalic says. “One way or another, it always comes down to this: ‘I love trees, but this tree needs to go.’”
At Overbury Drive, Rossi did not want the tree to go. He was determined the red gum should stay, even as it grew visibly sicker and sicker.
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“I think everyone just thought someone else was thinking about it, someone else was doing [something]. And when I realised they weren’t, that’s when I got a bit freaked out,” Rossi says.
He began dropping notes in letterboxes and arranged a neighbourhood meeting.
Rachael Nielsen and Carlo Jensen moved to the street five years ago and were among the 20 or so neighbours who turned up. They had been trying to teach their young sons to value and respect nature.
“We’re trying to teach Gerry that the trees are not ours,” Nielsen says. “We do not own the trees, even though they’re on the street outside our house and maybe in our yard, but we do not own the trees.”
A retired council arborist who lived one street over had also been monitoring the tree. His research of hydrological maps revealed the history before the bitumen, the Overburys and the colonisation of Kaurna Country: there used to be a creek running through Overbury Drive.
“Just by looking at the tree, you can kind of trace back its story.”
At the neighbourhood meeting last June 2024 the group learned that money would be set aside in the council’s 2024-2025 budget – along with a $180,000 plan to plant 440 new trees. But by December there had been little progress. The tree’s health continued to rapidly decline. Worried residents went to local media to raise the alarm.
That month the City of Unley council began installing four red water bollards around the base of the tree to deliver around 1,600 litres of water each day to the tree’s root system three metres below street level. In April, work will begin to rip up one lane of asphalt to create a half-moon of garden hugging the tree.
Just two months after the bollards’ arrival, the tree has started to bounce back; there are signs of new life, rather than a slow death.
“The leaves look greener, they’ve got colour in them,” Nielsen says.
“Either it’s about to flower, or it’s putting out new growth,” Rossi adds. “It’s about to do something.”
But while the tree appears to have been saved, Jensen is wary of failing to see the forest for the Sacred Tree – particularly after signing up to notifications from the state’s planning website.
“I get emails every week, seeing all of these significant tree removals, regulated tree removals, and that’s just in Unley council. And then you get emails from them that are like, ‘Oh, we need to do things to increase our tree canopy.’”
Caddy-Retalic says these tensions will continue as the demand for housing grows, putting a premium on every square foot of land.
“There’s a huge pressure to subdivide that block and put another house on it, or to widen that verge, or whatever it might be. And we’re really poor at quantifying the economic value of trees.”
For now, at least, Rossi feel a little better as he takes in that remarkable view out his window.
“I just couldn’t look at it because I thought it was too stressful,” he says. “But I can now.”
