Canberra’s bushland suburban mix is highly combustible says new fire risk study

Genevieve Jacobs 15 August 2019 27

Dr Price’s research focuses on high ignition zones in the densely settled inner suburbs. Image: Supplied.

We may be going through consecutive polar blasts at the moment, but Canberra’s unique combination of higher-density inner suburbs threaded through with bushland is a combustible mix, according to a newly developed bushfire mapping tool.

Add to that “a lot of ignition” in those areas, and Canberra’s heavily populated areas are at surprisingly high risk for bushfires, according to Dr Owen Price from the University of Wollongong.

Dr Price has used a newly developed bushfire risk prediction tool to map our biggest fuel loads and the likelihood of future bushfires in urban areas.

Initially developed in the Baulkham Hills area in Sydney, Dr Price then assessed Canberra’s risks for his work at the request of ACT Parks and Conservation.

“In the Hills district, most of the bushland is in the north and there’s a fairly clear distinction with closely populated urban areas, whereas Canberra has islands of forest within the town that my analysis highlighted as potential risks,” he says.

Dr Price points to a confluence of factors: a large concentration of houses, but also an ACT Parks and Conservation map that shows multiple recent incidences of small fires (above).

“The kindest explanation is that it’s carelessness, people tossing cigarettes out of car windows without thinking,” he says. Significantly for fire risks, Canberra’s reserves are islands of natural bush rather than controlled plantings.

Suburbs adjacent to bushland on the city’s southern, western and eastern edges are at an even higher risk than rural areas, according to Dr Price.

The Pierce’s Creek fire late last year was just a few kilometres from the nearest suburb. Photo: Jack Mohr.

His planning tool is something of a world-first, mapping bushfire risk based on objective records of past fire patterns. Dr Price believes that current prediction methods are too simple, often failing to account for varying factors like the amount, distance and direction of forest, fuel reduction from recent fires and ignition hotspots.

Dr Price’s new method considers ignition hotspots, a place’s distance from previous ignition points, the layout of forest in the landscape, time since the last fire, and the weather.

He calculated the risk to Canberra’s suburbs using data from ACT Parks and Conservation and the census. Factors included density, the direction in which houses faced, proximity to bushland and the last time that fuel sources were treated.

“The method takes planning from a heuristic approach where everyone relies on expert opinions and puts it into an objective, repeatable framework that compares one place to another. Fire agencies can then judge whether they’re putting their resources into appropriate places and whether there are any gaps,” he says.

Dr Price is quick to emphasise that there’s plenty of value in expert judgements and that his mapping method is another tool in a mix that often also includes simulator models.

“One of the key judgements is where to do fuel treatments, and this is more than guesswork and expert opinion. All methods have their drawbacks but you have to marry them all together to get the best-informed result.”


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27 Responses to Canberra’s bushland suburban mix is highly combustible says new fire risk study
Queanbeyanite Queanbeyanite 5:03 pm 22 Aug 19

It was all in the recent inquest over the 2003 fires. Phil Koperberg of NSW didn’t burn off the vast area of bush to the west and the ACT person responsible did nothing. Then they didn’t put out the fires burning there for months. So when it got hot and windy it sucked the fuel up and blowtorched the south. Only the change of wind direction at 4:30pm stopped everything south of the lake going up. A couple of hankercheif sized patches not burnt is ‘peanuts’. Back then the local council tried to nobble the Coroner. For a fraction of the cost of a day’s joyriding in ‘Elvis’ you could put cool burns through the NSW side every other year. They know what needs to be done but the Greens won’t let them.

Kimberley Lloyd Kimberley Lloyd 6:53 pm 20 Aug 19

You needed a study to notice that

Rob Bee Rob Bee 10:27 am 20 Aug 19

You need a new method to determine this?

Lisa Meredith Lisa Meredith 9:00 am 20 Aug 19

No really... you don’t say. 🙄

Margot Sirr Margot Sirr 8:56 am 20 Aug 19

Deciduous fire retardant trees and shrubs are the answer to this problem and should be the main planting around suburbs. I heard of some fireies saying that the reason a house was saved from fire was the camellias which were planted near the windows. This knowledge must be come commonplace and the government needs to realise that this is the only sure way of protecting the city — a buffer around and within the city of fire retardant deciduous trees .

Arleen Stark Arleen Stark 6:58 pm 19 Aug 19

I could have told them that for free, as it doesn’t take too much thinking to realise this. Gum trees in suburban streets, with their tonnes of falling bark don’t help either.

My husbands comment - “The dogs in the street know that!” (From a song we know, about stating the bleeding obvious)

Jeff Smith Jeff Smith 3:10 pm 19 Aug 19

Aranda, Wanniassa and Kambah really scare me with the sheer number of full size Eucalypts on almost every house block and green space in the area. I can't see how firefighters could ever protect the lives of residents in these suburbs if a bushfire gets in. There needs to be some prudent thinning of the trees in these Suburbs for longer term safety purposes and risk management. Obviously, with new plantings in Canberra green spaces to offset the tree reduction from these three suburbs. Other suburbs with more European trees are at a far lower risk.

Grimm Grimm 10:46 am 19 Aug 19

I think what they do in Victoria, allowing deadfall timber to be collected for domestic firewood, might help remove some of the fuel.

Kathy Vickers Kathy Vickers 10:06 am 19 Aug 19

"oh, easily fixed" says the ACT government "we'll just get rid of the bushland..."

Enid Bulman Enid Bulman 11:17 pm 18 Aug 19

How is this news? Has everyone forgotten those horrific fires?

Lucy Baker Lucy Baker 8:34 pm 18 Aug 19

Whether a suburb adjoining a “high-risk” coded area on the map is at risk depends on factors that aren’t obvious at a glance. For example, Ainslie adjoins a red-coded area but a fire on the flank of Mt Ainslie (and there have been many) always burns up and away from the suburb. Even houses adjoining the bush in Ainslie are safe if basic fire protection steps are taken. Strong easterly winds wouldn’t get past the mountain to force a fire into that suburb. Rest easy, Burghers of Ainslie!

HiddenDragon HiddenDragon 6:21 pm 18 Aug 19

Always nice to see serious academic attention to this issue, but to a considerable degree, this is a statement of the bleeding obvious – to anyone who is not in complete denial about bushfire risk in suburban Canberra.

Work like this should make plausible deniability that much harder to maintain than was the case in 2003.

Judith Herald Judith Herald 5:37 pm 18 Aug 19

Bush is flammable. House is flammable. Didn't need a thesis for that

Luke Black Luke Black 2:24 pm 18 Aug 19

Never Barr and geocon will perform hazard reduction by building more units...problem solved

Capital Retro Capital Retro 8:36 am 18 Aug 19

Is there a link to a clearer version of the map supplied, please?

Erin Nugent Erin Nugent 6:25 am 18 Aug 19

Ummmm you buy a house in the Bush capital 🤷‍♀️

Kim KD Winks Kim KD Winks 4:20 pm 17 Aug 19

And yet the greenies still complain when controlled burning needs to happen.

It’s nearly been 20 years since 2003 and still no help with reducing these fuel loads. The RFS and local cockies can only do so much. But wat h the uproar if another suburb goes up in flames!

    Anura Samara Anura Samara 11:04 am 18 Aug 19

    As you know, the window of acceptable conditions for HR burns is narrowing each year.

    Jonathan Clarke Jonathan Clarke 12:54 pm 18 Aug 19

    Kim KD Winks It's mostly asthmatics and health care providers who complain, in my experience . Most environmentalists I know recognise the need and value of controlled burns.

    The aim is carry out controlled burns on 5% of the ACT every year.

Chris Bennett Chris Bennett 4:00 pm 17 Aug 19

As long as it's managed correctly... This report identifies the risk, so that it can be mitigated.

I wouldn't want them bulldozing all the bush though.

Robert Hawes Robert Hawes 3:15 pm 17 Aug 19

It’s one of the reasons I love living in Page, there is no bushland anywhere nearby to burn.

    Amanda Adams Amanda Adams 3:42 pm 17 Aug 19

    Robert Hawes absolutely,agreeI would never want to live near any bush land here,it’s only a matter of time before we have another bad fire, they just keep on ignoring all the bush,and cannot foresee any fire risks. I was in page last fire it was scary enough

    Arleen Stark Arleen Stark 7:02 pm 19 Aug 19

    Me too, in Kaleen.

Aaron Wishart Aaron Wishart 2:25 pm 17 Aug 19

Well duh...! 😂😂💁

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