Fire!
I offer the following tentatively, noting that fire is a hugely vexed
issue. My experience and responsibilities have included: fighting
wildfires, lighting fires for biodiversity management, having had family
members lose their houses in fires, wondering what the outcomes of a
coroner's court would be for fires in my area of responsibility and
accountability, going to fires to watch birds, and studying fire ecology
at uni. I have retired recently and one of the very best things about my
retirement is the huge relief of no longer being responsible for fire
outcomes.
Some Australian plants can't take fire at all. These include many
Australian rainforest species. Others need fire in order to germinate
and thrive. Others can take fire, but do best with specific fire
regimes. How hot the fire is, time of year, time since last fire, are
all variables that favour some species over others. In Northern
Queensland, where eucalypt and rainforests abut, if fire is excluded,
the rainforest edge tends to expand. If fire touches up the rainforest
the eucalypt forests advance. Mulga is disappearing over vast areas of
the arid interior. A mulga tree takes about seven years after
germination to set seed itself. Huge wildfires are now happening more
frequently than every seven years and grassland is taking over from
Mulga. Introduced Mission Grass is changing fire intensity and, most
likely, as a result, species diversity in inland Australia. Birds are
responsive to individual fires. If you want to have a good look at a
whole range of northern Australian birds, head for the smoke of a fire.
Birds which have specialised habitat needs will also be affected by
changes to vegetation generated by changes to fire regimes.
Cook recorded fires all along the east coast. It is clear that
Indigenous people affected the composition and structure of Australia's
vegetation and that they did so deliberately to suit their purposes.
While they burnt locally, they affected vegetation across the continent.
In doing so, they favoured not only certain species of plants and the
structure of vegetation but also the composition of the fauna. Early
settlers recorded galloping their horses across country through which
today you can hardly walk.
Fire regimes are affected by variables such as sources of ignition,
fauna and flora species composition, patterns of herbivory, hydrology
and climate. In turn these variables are affected by fire regimes. So
there is a dynamic interplay between the variables. Since 1788 there
have been massive changes to all of these variables. Some people have
ascribed the huge increase in the size and intensity of wildfires
world-wide as being the result of climate change. Certainly, once a
wildfire is going in extremely adverse conditions, fire managers are
struggling to protect lives and property, let alone to stop the wildfires.
The risks of fire having an adverse impact are much greater than they
used to be because of changes of settlement patterns. Tree changers, sea
changers and bush capital dwellers all like a few gum trees around the
place. When heated, eucalypt foliage generates explosive gases which can
greatly increase the intensity and speed of wildfires. (Why not? Most
eucalypt species are winners when it comes to fire.)
Natural resource managers are beset by conflicting priorities including
the protection of life and property as well as biodiversity. There is a
new priority which is to lock carbon in forests. Burning them releases
the carbon into the atmosphere. But generally, natural resource managers
are held most accountable for losses to life and property and now
routinely find themselves the subject of coroner's courts and public
enquiries if life and/or property is lost but not if biodiversity is
lost. In such enquiries they can be subject to criminal sanction and,
increasingly likely, subject to civil sanction. Their careers and
livelihoods are at risk. The issues are always heavily politicized.
Everyone rates themselves an expert. There is a fair bit of shouting
from the rooftops by partly-informed loudmouths, often with simplified,
single line, views. This fits the thirty second grab on the evening
news. The press likes emotional human interest stories which, during
fires, is about he loss of homes and photographs, or worse still, the
loss of family and friends. The emotion and pathos is raw, real and
instantly accessible to the general public. If there is a biodiversity
angle to the news, it is generally the pathos of a part-burnt koala or
kangaroo. The finer points of fire and its relationship to biodversity
and to ecological systems generally don't rate a mention, let alone
serious consideration or examination. For managers personal stress in
protecting property and people during a wildfire can be enormous, as can
the stress when property and lives are actually lost. Over the years
some of them have also had to address the terrible consequences of
having staff burned to death.
The answer is that because of the changes to all the fire regime
variables, because of conflicting priorities, because of conflicting
views about risks, and because of differences from one place to another,
there is no easy simple general answer. Back burns, control burns,
biodiversity burns, traditional Indigenous burns and fuel reduction
burns are all best efforts by someone who is trying to balance a number
of risks and priorities, often in circumstances where the real level of
the ability to control events is low. (There is a traditional firies'
joke: What do you get when you light a backburn? Answer: Two wildfires
instead of one.) On the other hand, the sympathies, values, views and
the approaches of individual managers can affect the way fire management
and fire preventative works are carried out. We need too, to be mindful
that the rules cannot be fixed. Climate change and its impact on
wildfires will change 'the rules' in a big way.
What we can do is help keep biodiversity values on the agenda, recognise
the conflicting priorities as having validity for the values of other
members of our society, encourage firesafe design in houses, increase
what we know about fire and its impacts on biodiversity, disseminate
that knowledge, work with natural resource managers and fire managers to
minimise the adverse impacts of fire management and prevention works on
biodiversity, and maximise the positive impacts of deliberate fire on
biodiversity.
Con
John Layton wrote:
I was interested to read Ben Whitworth's and Mark Clayton's comments
regarding local land clearing and controlled burns – food for thought.
To state the obvious, it's a subject far from immune from controversy.
I'm often challenged by the question: Australian plants have evolved
to survive fire and recover well, often with seemingly renewed vigor.
In fact many seeds require fire in order to germinate, so what's so
bad about a bit of controlled burning. So what's the answer in a
nutshell? I want to put it in my mental file for future reference at
short notice.
Good to be reminded that /Acacia baileyana/ provides food for Superb
Parrots. I've often sided with the opinion (expressed on this chat
line just a couple of days back) that introduced plants can be
important for birds.
Some years ago, while walking on Black Mountain, a David Bellamy type
hurled his pack down, threw his arms out with palms upturned, rolled
his eyes towards the firmament and bellowed like a lovelorn camel. I
thought Black Mountain's formidable Formicidae had encroached upon his
sensitivities. With that he tore a seedling /A. baileyana/ from the
ground and held it triumphantly as if he'd captured the botanical
equivalent of Osama Bin Laden. I gave him a ten-second verbal burst,
primarily because he spattered me with moist earth and, secondly,
because I have a low tolerance for such silly histrionics as I believe
(probably a no-brainer) they do nothing to advance the cause of
reasonable, erudite conservationists.
John K. Layton
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