Our Understanding Of Fire
by Phil Maguire, Bundarrah Days, March 12, 2009 [here]
I WAS very young when I first become familiar with the term bushfire. I was so used to hearing it I grew up believing that fire in the bush was something that we Australians just accepted as a fact of life.
I didn’t know back then that fire came in different varieties depending on what was being burned and when. Too many urban Australians still don’t know that simple fact and merely repeat parrot fashion what they’ve been told by the green movement - “fire is a natural part of of our environment - get used to it, dude!”
There’s something really aggravating about being told to get used by fire by someone whose knowledge of fire in Australia is as lacking as their understanding of Australian vernacular.
The answer of course, is this. “Fire is a natural phenomenon mate, but how bloody natural is it when it’s your hair in flames, ay?”
Let’s get down to some facts. Australia’s native flora and fauna has evolved with fire from the very beginning. Man’s flirtation with fire on this continent started about 40,000 years ago. The Aborigines farmed with fire using it to clear ground for walking, to provide grass for game and even to nurture specific plant communities. This pattern of burning created a mosaic of recently burned country across the landscape that limited the spread of wildfires.
In addition to Aboriginal burning, lightning has always been a prime source of ignition. Lightning fires, however, often occur in relatively benign conditions and can be suppressed quickly, often by moisture, unless, as has been the case in recent years there is a massive fuel burned available to burn.
Too many urban Australians fail to understand that our forests have changed significantly since European settlement. If they were confronted by the same bushland as the explorers encountered they wouldn’t recognise it. And just as the bush has changed so has the nature of bushfire.
Nowadays the absence of frequent burning leads to a build-up of fine and heavy fuels resulting in the kind of holocaust fires we saw on Black Saturday.
The management of forests and fires is incredibly complex. The green mantra that “fire is natural, dude - get used to it” is far too simplistic and ignorant to warrant serious consideration and yet it rules the day. One tragedy leads to another.
We have to find a solution to our fire dilemma. Over the past six years lack of fuel reduction burning has lead to a massive increase in the area of bushland burnt by high-intensity fires - more than 4 million hectares since 2003.
There’s also another problem. The exclusion of fire in eucalypt forests and woodlands, in the absence of other fuel reduction strategies, causes the proliferation of shrubs and litter. It’s a fact that shrubs can significantly change the conditions in which overstorey eucalypts are growing. A shrub understorey shades out the forest floor, decreases soil temperatures and increases the moisture of the soil. Heavy layers of organic litter effectively mulch the forest floor causing changes in soil chemistry by altering the nitrogen cycling regime. These kinds of changes increase the vigour of pests and pathogens which in turn affect the health of the forest.
In addition, and we’ve pointed this out so often, when forests develop a scrub understory it burns for longer with much greater intensity, and as the trees have not evolved with these kinds of fires their health is badly affected.
