Who decides where to conduct fuel reduction burns and what goes into their planning?

13 June 2020

Published by https://www.abc.net.au

AUSTRALIA – Planned burns can help reduce the severity of bushfires — but they’re often the subject of emotionally and politically-charged debate.

So have you ever wondered who decides where hazard reduction burns should occur or when they will actually take place?

Let’s take Victoria’s Otway district as an example.

Its 9,081 square kilometres account for around four per cent of Victoria’s total land mass but about 20 per cent of the state’s total bushfire risk.

The area includes the Great Ocean Road, so there’s always a large tourist population, especially in summer.

Deputy chief fire officer Andrew Morrow is one of the region’s strategic planners.

You might expect him to be looking ahead to the next fire season, but actually it’s far too late for that.

Since the catastrophic Black Saturday fires in 2009, strategists have been looking 40 years into the future.

It might seem like an overwhelming prospect so for starters, he rules out areas of wet forest that simply won’t burn.

But it still leaves a lot of land to consider.

Computer modelling helps identify dangerous sites

Human life and homes are at the top of the priority list, so identifying key population centres is a must.

But there’s also critical infrastructure to consider; important access roads, water reservoirs, habitat for endangered species.

And you’ve got to be strategic: you’re working with limited resources and an ever-shrinking window of opportunity weatherwise.

So where to begin?

To start, Mr Morrow and his team split the region into a giant patchwork quilt, made up of “burn blocks”.

He then uses a computer modelling program to runs hundreds of fire scenarios through the landscape.

The modelling looks at what would likely happen if you burnt here didn’t burn there if a fire started here or there, and how a wind change might affect even the best-laid plans.

It takes into account where crews have burnt in previous years and where fires have occurred naturally.

Complex mathematical equations are swallowed up by the computer, spitting out the best and worst case scenarios.

It identifies the points where fires are most likely to go on to cause mass destruction.

“We can identify the areas in the eastern Otways where the fires can potentially run into the Surf Coast communities, from Lorne to Fairhaven, Aireys Inlet and Anglesea,” he said.

Stopping fires before they race uphill

In simple terms, the Otway region consists of private land to the north, which then slopes up the Otway ridge before sloping back down towards the coast.

Because fire travels faster uphill, the team wants to reduce the risk of fires coming out of private land, “ramping up” into the bush and spotting over into coastal communities.

“If fires are going to come into the bush, we want to slow those down,” Mr Morrow said.

“Having recent fuel reduction in those areas stops that ramp up the slopes.”

Even burns conducted five years ago can make a big impact.

We burn the bark off the trees,” he said.

“That’s the thing that takes it from a ground fire to an elevated fire into the crowns — and that lasts the longest.”

Slowing fires down

Last season, the Otway region had a relatively tame fire season.

The largest blaze was the 347-hectare Boggy Creek fire, near Gellibrand, which burned into an area where a planned burn had been conducted two years prior.

The impact of the fire hitting that old burn zone was obvious — the fire slowed down, making it easier and safer for crews to access.

“Without that [previous planned] burn there’s quite a likelihood that the fire would have ran up and threatened houses on the west side of Gellibrand,” Mr Morrow said.

The computer modelling has helped identify a second key focus, which will be reducing the risk in a 2-kilometre arc surrounding population centres.

But with many small towns and thousands of hectares of land where does the team begin?

Time to work out what’s possible on the ground. Forest fire management officer Jenny Howell is the expert here.

“We’re taking a 40-year theory and we’ve got to determine if we can actually realistically do that on the ground,” she said.

“We figure out what we can do in the next three years.”

The team undertakes reconnaissance missions to check the aerial photos used by strategists actually match the reality on the ground.

Sometimes tracks they thought existed are overgrown, or completely inaccessible, or dangerous trees need to be removed.

Up to four years of planning can go into delivering a single burn.

And with about 7 per cent of planned burns each year occurring on private land, the team needs to speak to each individual landowner to check they’re on board.

In this region, a single planned burn might involve up to 10 private landowners.

Each of those will need to specify what they’re willing to lose.

“Some have fences that are in a state of disrepair and are happy that they get destroyed,” Ms Howell said.

Stock might have to be moved, fire crews given access to private tracks and some paddocks might be transformed into temporary air bases.

Ms Howell also considers the impact on public roads, the protection of infrastructure such as Telstra cables and water pipelines, and the impact on native species who might live in the burn zone.

Along the Great Ocean Road, crews can’t burn too close to the cliffs because the vegetation helps reduce rockfall so planes are required to drop flame retardant along the road.

“There’s years of work to go through before we actually ignite that burn,” Ms Howell said.

Finding the right window

So now we know that it’s technically possible and strategically worthwhile.

It’s time to work out how the community feels.

Are there times where events are on and smoke would be particularly unwelcome? Could it hurt peak tourist season? Or are there aesthetic values to protect?

These are all questions Bodin Campbell asks during meetings with community representatives.

“We don’t want anyone to be surprised,” he said.

When the team thinks there might be a window they’ll go to the community with a proposed date.

“Almost always we get the feedback that, yes, the smoke is a bit of a pain, but we think you should do it,” Mr Campbell said.

“That’s the sort of resolve that we’re just so humbled to have within our community.

Aiming to complete the top 10

Each year there’s between 25 and 40 burns that make it through this process and end up in the queue.

Some of them are more complex than others.

In reality, the team would be happy to get through the top 10 in a season.

So which ones get the tick?

Time to turn to the weather.

The team has a direct line to a senior forecaster at the Bureau of Meteorology and gets the most up-to-date forecasting at least twice a day.

They also go out to monitor the fuel moisture levels on the ground.

It doesn’t take much to throw their plans into chaos.

A planned burn organised for Lorne this autumn was scuttled by just 3 millimetres of rain two days beforehand and had to be rescheduled.

Ms Howell said the window of opportunity to conduct a burn safely and efficiently was getting smaller.

“It’s days of weather as well, not just the day of ignition,” she said.

“Some of the grassland burns are a two-hour job and they’re done and they’re clean and minimal requirements after that. But other ones might take three days of ignition.

“We’re not just talking about having our day of opportunity. We also need to know what the system is looking like for the days after.”

Fires can be bumped up the priority list if they’re alongside burns from previous years, creating that valuable “patchwork” of burnt area.

Burning alongside previous fuel reduction burns also makes planned burns easier to control because there’s less chance the fire will spot over that edge.

The priorities

Finally, after years of work, Mr Campbell is able to outline the priority burns:

  • A cluster of three burns around Lorne.

“The primary driver there is the protection of Lorne,” Mr Campbell said.

“It’s a huge interceptor in the run of fire.”

  • A small burn in Fairhaven/Moggs Creek to build on other burns recently conducted in the area.

“It really starts to harden up some protection for those communities which are pretty exposed without any fuel reduction.”

  • Completing a burn at Aireys Inlet.

“Last year we treated a heap of the drier, heathy fuels late in the autumn and our focus now is to get in and do the stuff right up hard against town.”

  • An inland burn in steep valleys at Barwon Downs.

“This one registers as a priority for us because again it’s that concept of [fire coming] out of private land, fire ramping up the ridge and spotting over,” he said.

“It’s also just practical to tack on to where we’ve just burnt. It means that one control line is a lot less stressed, we can use our resources efficiently and complete that burn.

“It’s actually a really complex burn in many ways so it’s fantastic to make it just that little bit easier for ourselves if we can.”

Essential service see burns continue through pandemic

Planned burns have continued throughout the coronavirus pandemic but there have been a few adaptations, including having crews monitoring the burns’ progress remotely via Zoom.

Mr Morrow said all the planned burns would be effective “to varying degrees” when fire season arrives.

“Once we get up into the extreme and code red conditions what the benefits will be is that the burning will slow down the spread of the fire,” he said.

“Buying time is part of that equation.”

He said while fire crews were managing the risk year-round, there were a range of things the community could do to help, including managing fuel loads around their own property and getting involved in the scheduled burn planning process.

“We’re looking to find the opportunities to manage bushfires 365 days a year,” he said.

“But having this as a shared responsibility is — for mine — the crux of what we’re on about.”

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