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Fires threaten centre's river red gums

On the banks of the Todd River north of Alice Springs, ethno-ecologist Fiona Walsh describes the threat that fires and buffel grass are posing to the river's iconic river red gums.
On the banks of the Todd River north of Alice Springs, ethno-ecologist Fiona Walsh describes the threat that fires and buffel grass are posing to the river's iconic river red gums. Glenn Morrison

HUNDREDS of years old, the iconic river red gums of Alice Springs are under threat from firebugs and the unchecked spread of buffel grass, one of a suite of introduced grasses dangerously altering Australia's outback ecosystems.

The smooth bark and majestic, spreading branches of Eucalyptus camaldulensi have made them a friendly and familiar site on most Australian inland waterways.

In central Australia, where dry river beds provide sufficient underground water to sustain their growth, the trees provide shade capable of lowering ambient temperatures by a welcome 10C or more, a life-saver in the desert heat.

But shade is only one of many pragmatic reasons why the species is so widely valued by Aboriginal and settler Australians alike.

As this article was being prepared on Monday, however, firefighters were trying to save a tree in the town's CBD, after a weekend in which sections of the Todd River's banks were severely burned out between town and the Alice Springs Telegraph Station.

The burns are part of a now daily battle waged by firefighters against what has been described as a "tsunami" of buffel grass engulfing the Todd riverbed and other environs in central Australia.

"Over the weekend there was a fairly large fire in the Telegraph Station area," says acting senior station officer at Alice Springs Fire Station, Tony Miles, 43.

"Up until Friday we had 144 grass fires for May, and 70 of these involved waterways, either in the Todd River or Charles Creek.

"I'd estimate we had about another 20 fires at the weekend; that's an estimate only, I haven't done the figures yet, but there were eight call-outs last night alone."

And all of the fires were deliberately lit, says firefighter Miles.

"For us that's the problem," he says. "There are multiple arsonists, and we're pretty helpless to do anything about that."

The situation highlights not only the nuisance of firebugs, but the serious threat to a natural resource not easily replaced in rivers once high in biodiversity and described as the food bowls of the region.

Aside from the firebugs, the real culprit is the buffel grass, or Cencrhus ciliaris, which has spread voraciously across the centre, since being introduced on a mass scale as a dust suppressant in the 1950s and 60s.

Ethno-ecologist Dr Fiona Walsh, 53, has observed the problem over some 24 years,

She describes her role as someone who brings together people and their relation to plants, animals and ecology.

As for the river red gums, Dr Walsh thinks of the trees as the centrepiece of Alice Springs.

"Aesthetically and functionally, for both natural systems and an urban aesthetic - our visual landscape - they're dominant.

"The shade, the bush food resources, and individual trees also feature as major Dreaming points."

As well as being part of sacred Aboriginal mythologies, Dr Walsh calls the trees a "boarding house" for native animals and insects.

"The concept came from a poster that was done in the 80s; it describes the idea of the trees being full of animals that occupy different habitats.

"I say they are like magic faraway trees. There are termites in the timber, witchetty grubs channel through the wood, bat species in the hollows; and birds, particularly parrots, and as well the trees are full of insect scale and nectar."

For Aboriginal people, the trees were a significant resource.

"There are two witchetty grubs, one in the roots, one in the trunk, the timber is used for artefacts, and particularly the bark.

"Then there is a lurp, a manna or scale, on the leaves in the spring; it's sweet and kids can scrape it off, collect it and roll it into balls like fairy floss.

"And there is a sweet sticky gum forms in the canopy in the hot season.

"Goannas live in the hollows as well, so they were a habitat for animals that people hunted."

The threat posed to the trees from buffel grass comes down to the way it burns and its ability to spread.

Originally from Africa, the strong, deep-rooted and drought-hardy grass is widely favoured by pastoralists, who rely on it as a life-saving feed in dry times. Others describe it as a "moving cancer", and "the botanical equivalent of cane toads".

"The buffel has a thick, woody tussock," Dr Walsh says. "And it grows much taller and thicker than the native grasses.

"When a fire comes along it will dwell, meaning it sits at the base of the tree, where it burns and burns, making a triangular-shaped scar at the bottom of trunk.

"The first fire can eat through the bark, but repeated burning before the bark can heal itself means it burns into the heartwood.

"Once the fire reaches into sections hollowed out by termites and other insects, it starts to burn upwards much more quickly because the hollows act like chimney flues.

"They draw the fire up into the heart of the tree, until the tree turns into large chimney stack."

And that means a burning tree is difficult for firefighters to extinguish.

"On a first attack we'd put on about 3000 litres of water," firefighter Miles says.

"Sometimes that's enough to quell it, but because the fire is so deep-seated in the tree, they can keep burning and we might have to go back a couple of times.

"Some trees could end up with 9000 litres on them."

Firefighters are due to begin a series of cold burns across Alice Springs next week, fires of purposefully low intensity as part of a fuel reduction strategy.

The fire service also clears around the trees, and nominates hotspots to government, council and other groups in a riverbed suffering from being divided into multiple jurisdictions, meaning it is sometimes confusing as to who is responsible for a particular reach of river.

Nevertheless, the town council and NT Government slash the buffel in the river and where it borders properties around the town, in order to reduce the intensity of subsequent fires.

But such actions only make matters worse in the long-term, says Dr Walsh.

"Slashing promotes the growth of buffel grass, it likes being grazed.

"The actions reduce fuel in the short-term, but are actually exacerbating the problem in the long-term."

Dr Walsh advocates instead a co-ordinated approach, involving hand removal, spraying and community engagement.

"Slashing needs to be combined with the removal of the tussock, [and] will only be effective when systematically combined with other management measures.

"And yes, it's a government and council responsibility, but it's also a community responsibility. We all benefit from the river.

"People can join a local Landcare group, like new Olive Pink Todd River group, and there are at least five other groups in Alice Springs."

On Sunday, about 60 people attended the first meeting of a new Landcare group devoted to claiming back the Todd River.

The group will be based at the Olive Pink Botanic Gardens and led by ethnobotanist Peter Latz.

Topics:  alice springs fire


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