Bushfires have burnt more than 1.2 million hectares (4,600 square miles) of Australia this summer.
Some blame the ferocity of this year’s fires on global warming, others on inadequate control burning claiming that fuel loads in many forests are too high.
Bob McDonald has a very different perspective suggesting that both the frequency of bushfires and fuel reduction burning has increased over the last two decades in parts of eastern Australia and that in some situations the best strategy is to not undertake any controlled burning as potential fuel, including leaf litter and wood, will be quickly broken down by termites, bacteria and fungi:
“The frequency of both fuel reduction burning and fires have increased over the last twenty years in many locations. There may be no relationship between the two, but I suspect that in some situations more frequent burning is contributing to more fires.
My grandmother was saved by her father cutting and bleeding her hand when she was bitten by a snake. He didn’t actually do the right thing but she believed he did – was calm and survived.
If anyone had argued with the my great grandfather on the day he cut his daughters hand I likely would not be here to write this – so I respect all those views contrary to mine on an issue for which many have strong and personal or professional views and I am prepared to be wrong – but first we need to have an objective look at what has happened with fuel reduction burns in the last twenty years on a site by site basis.
I have fought fires in several places and I am interested in questions relating to what does not burn, when vegetation burns, how hot does it burn and which fires can ignite what kinds of dead wood.
Wire grass, for example, explodes but you can run through it without getting burnt.
In the 1983 Ash Wednesday Fires at Mount Macedon (on a south westerly wind) frequently burnt as well as bush with that went up in a crown fire and also burnt. A fire from the north just 10 days before the Ash Wednesday Fires, a wet gully of ferns and old trees on the south side of the Mount Macedon ridgeline held up a grass fire for two hours enabling water bombinmg and eventually being put out.
In 2003 roughly 500,000 hectares of forest from East Gippsland to Canberra was burnt. When fires two weeks ago reached this area, burnt less than three years ago, they not only burnt but ‘took off’. This would suggest that in some situations re-growth is more flammable than un-burnt areas and that in some cases a significant amount of fuel reduction burning could actually increase the frequency of bushfires.
In East Gippsland, while developing a Community Fire Protocol to manage fuel reduction burning, locals pointed out that rainforest gullies slowed fires and it was a good idea not to burn them in fuel reduction burns.
In coastal rainforests strips in northern NSW there is no fuel the litter life is so intense that even leaves remain in a light single layer and fallen timber rapidly becomes soil.
Termites play a big role here, along with fungi and bacteria. If it was burnt this forests’s capacity to rot timber would be significantly reduced.
It will take time for people to feel comfortable with letting the bush grow out in places where no-fire is, in my opinion, the best hazard reduction strategy. All vegetation burns, dead and alive, but some burns better than others. Fuel reductions fires in sandy country in the south that generate braken invariably increase braken denisty, height and the fire hazard – and often kill thin barked eucalypts like Manna Gums, for instance