INDUSTRY & RESEARCH
campusreview.com.au
Lay of the land
ABC photographer Matt Roberts reacts to seeing his sister’s
destroyed house in Quaama, NSW. Photo: Sean Davey, AAP
UTAS professor on the
complexities of land management
practices in bushfire mitigation.
David Bowman interviewed by Wade Zaglas
I
n part three of our series on the
megafires that brought destruction
to Australia this summer, Campus
Review spoke to Professor David Bowman
from the University of Tasmania, a world
authority in land management practices.
He talked about the challenges of
reducing fire loads, the ability of megafires
to overcome fire containment lines, and a
question that is leading to intense debate
in the field: Will more controlled burning
lead to greater carbon emissions in the
atmosphere than intense bushfires or even
megafires in the future? And what will be
the implications of this?
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One of the salient points Bowman
makes is that Australia’s landscape is not
an idealised, homogeneous environment
that makes controlled burning easy. As
he puts it, Australia is not a “frictionless
surface” – it’s full of tropical areas, grassy
plains, deserts, and a whole host of other
complicating factors.
He also warned that the scale of
controlled burning required to establish
firebreaks across the country would be
“mind-boggling”.
CR: We know that controlled fire burning
can help contain the spread of some fires,
but what about megafires?
DB: This is one of the big questions
in applied fire science that we’re still
struggling to answer. And the recent fire
event in eastern Australia has given us a
treasure trove of data and opportunities to
help in teasing apart these factors.
The standard premise is that you can’t
control the weather, but you can control
fuel and you can partly control ignitions.
You have ‘total fire ban’ days, but you are
going to get lightning, and accidents, and
bad actors causing ignition.
The fatalistic view is that there will
be ignitions, so there will be fires in the
landscape. The idea is that if you can
reduce the fuel – that’s why sometimes
prescribed burning or hazard reduction
burning is called fuel reduction burning –
you can reduce fuel loads.
The question is, what does that achieve?
One optimistic view is that it creates a fire
barrier, so it stops the fires spreading across
the landscape. A more realistic view is that
it probably changes the behaviour of the
fire, particularly the intensity, making it
more amenable to control or suppression.
And making the fire behaviour less
extreme increases the odds of asset
survival, and to a certain degree human
survival, because the intensity of the fire
is lower. And because the intensity of the
fire is lower, suppression activities can
take place, because after a certain point
all known technologies cease to be of
any relevance.
So the idea of fuel management is to
drive down the intensity and give fire
managers more options and capacity
for control.
Unfortunately, it gets very complicated
very quickly. On the one hand, does it stop
the fires? The idea is that you can use fuel
reduction burning to create barriers. Freshly
burned areas are barriers, but it’s not
possible to have barriers everywhere.
Most people don’t promote the idea that
fuel reduction burning is creating barriers
just because of the practicality. If you
think about it, how would you be able to
generate that much freshly burned country
to fend off a wildfire? It boggles the mind.
In the lead-up to the fire season, how
could you treat such a huge amount of
area to create freshly burnt firebreaks?
So it’s not practical, but people can
confuse that. They think that fuel reduction
burning is creating firebreaks. It can and
does create firebreaks; it’s just the scaling
issue that is mind-boggling.
The second point of fuel reduction is
that the behaviour of the fire is likely to
change because there’s less fuel to burn.
However, there are two really important
caveats that are misunderstood.
The first is the live fuels. The landscape
is complicated. It’s got terrain, vegetation,
water courses – all sorts of complexities.
It’s not just a frictionless surface. The
models that are often used discount that
complexity, particularly the live fuel, the
vegetation.
If you start burning an area to reduce
its fuel, you will reduce it, particularly in a
dry forest. You will reduce the amount of