Green firebreaks the solution to Hobart suburbs going up in smoke
Peter Boyer says it is time to support a potentially contentious wildfire safety strategy
HOBART residents do not need reminding of this city’s unique mix of spectacular scenery, old settlement and vibrant, diverse population. We see it daily, and we love it.
Part of the city’s appeal is its shape. Greater Hobart is not your regular metropolis, spreading in all directions from the centre, but a long, narrow strip between mountain and sea. White caps on the estuary and the mountain’s forests and scree slopes are never far away.
About 100,000 lived in the metropolitan area when the 1967 fires roared through. Now about 230,000 are squeezed into that same corridor, augmented by expansion into adjacent municipalities and, crucially, deeper into the foothills of Mt Wellington.
Hobartians’ coastal views and easy bush access are the envy of residents of other Australian capitals. But that long bush boundary makes them vulnerable to wildfire.
The narrowness of the residential area limits travel route options, a point not lost on commuters stuck in last week’s mega-snarl. Nor is it lost on residents of Hobart’s forest-fringe suburbs.
A late-summer Fern Tree fire-season briefing, jointly organised by Hobart City and the Tasmania Fire Service, was memorable for its candid discussion of options available to fringe-dwellers facing a rising fire risk with drier, warmer summers.
Losing your home is not as bad as losing your life, but is pretty bad, and with limited route options you could still die if you leave your escape too late. There is also the matter of rising insurance premiums for homes near the forest, which is regarded a powder-keg ready to explode.
As fire ecologist David Bowman sees it, every Hobart resident should take notice. Professor of environmental change biology at the University of Tasmania, Bowman has made a career out of studying Australian bushfires. Hobart’s geography, he says, makes the whole city vulnerable.
At our community briefing, Bowman raised the idea, though not endorsing it himself, that fringe-dwellers should simply get out and stay out, leaving the bush to its own devices. That raises the prospect of relocating large numbers of households, with more to follow as the bush moves in.
There is the alternative of planned year-on-year understorey burning, or prescribed burning, recommended by the royal commission into Victoria’s devastating 2009 fires. Prescribed burning is used in Victoria and Tasmania, but is not without its critics.
In a paper published last year in the International Journal of Wildland Fire, Bowman and two other Tasmanian scientists, James Furlaud and Grant Williamson, described the results of computer models used to simulate tens of thousands of wildfires across Tasmania.
They found that prescribed burning will not do the job
unless it covers a third of the state’s area every year. Less extensive burning was found to be of little value except when done next to homes. But all burning has public health consequences and carries risk of fires escaping.
There’s another issue, to do with a warming climate. California’s 2017 fire season was fully six months long, with blazes as late as mid-December. Our fire season is lengthening too, limiting the window for prescribed burning.
Where does that leave us? Believing that the urban fringe should not be abandoned, Bowman and his colleagues came up with another idea. But it will demand a big shift in the way we view our natural environment.
They call their idea “green firebreaks” and describe it as “careful landscape design at the local scale”. It sounds uncontroversial until you unpack it. Green firebreaks as Bowman describes them are areas around the upper perimeter of Hobart’s settled areas that have been largely cleared and replaced with thinned bush, less flammable tree plantings and grassy areas grazed by native animals. They would be serviced with piped water and would be quite wide, preferably hundreds of metres to allow a chance of defending nearby homes. They would be visible at a distance, but after a few seasons their visual impact would be slight.
Perhaps we are headed back to the future. Early European explorers recorded Aboriginal people using fire to maintain open lands, and as recently as the 1960s settled mountain slopes behind Hobart had much more cleared land than today.
Bowman’s thoughts will raise eyebrows. We see trees as needing protection, as indeed they do, but we have to acknowledge the dangers that an unbroken eucalypt canopy poses for settled areas. This is an idea whose time has come.
On another subject, where is climate change in the state election campaign? The three main parties seek to answer that question tonight in a public forum at Scots Memorial Church Hall, 29 Bathurst St, Hobart at 7pm.