Bush Fire Front Occasional Paper No 3
BIDI BURNING: Shall Bushfire be Our Friend or Foe?
by Dr David Ward
Given summer lightning, and vandals, bushfire is an unavoidable feature of the jarrah forest. Since it is inevitable, we have to choose between making fire our friend, or our foe. Nyoongar people made fire their friend, and so lived, for thousands of years, in and near the jarrah forest. They had no firetrucks, water bombers, television journalists, or the Salvation Army to give them breakfast. Their fire management was more intelligent, and frugal, than ours. Through history and mathematics, we must learn from them, before our summers become a nightmare of uncontrollable, and unaffordable, bushfires.
As recently as 1966, a Conservator of Forests, Roy Wallace, talking of the 1920s, said that it is not unreasonable to assume that the forest was completely burnt through every 2-4 years. Even as late as 1925 the writer was able to observe three fires of this nature in unmanaged virgin forest east of Jarrahdale. These fires were alight in December and continued to burn until the following March.
It was only after the First World War, under Charles Lane-Poole, that the Forests Department began trying to suppress bushfires. At first, the department would send one man, on a bicycle, to put a fire out. He carried an axe on his crossbar, and cut down a marri sapling, with which to beat the fire. This is only possible in 2-4 year old fuel. As fuels have become heavier, due to ill-advised fire exclusion, so the bushfires have become fiercer. Imagine one man, on a bicycle, being sent to fight that recent fire at Karagullen. Fire is now, needlessly, our foe, and fire is winning.
Lane-Poole’s aversion to fire was based his training in France, and on advice from his mentor, the international forestry consultant, Sir David Hutchins. Despite his hatred of forest fire, Hutchins had to admit, in a 1916 report to the West Australian Government, that …”from an unknown period the Australian forest has been subject to the fires of the Blacks, fires lit for the purpose of providing food and hunting-grounds for the game. With the advent of the Whites, the fires have become more severe….”
An even earlier observer, Joseph Strelley Harris, was the first Inspector General of Timber. He was an excellent bushman, and mixed much with Nyoongar people. I believe his descendants still live in Perth. In 1882 he said, in a report to the Governor, “There would be practically no difficulty in stopping bush-fires, but no great advantage would accrue from the attempt – sooner or later fires will come, and the advantages gained by bush-fires more than counterbalance the disadvantages. In fact, such conflagrations are frequently advisable. Leave the forest unburnt for a few years, allow the shrubs to flourish, fallen trees to thicken on the ground, with dead leaves impregnated with turpentine, to accumulate and the destruction of the aged Jarrah, the many young plants and seeds will be completed. Allow the fires as a rule to take their course – if possible every 2 or 3 years.“
The Nyoongar word for a track is bidi. There were many throughout the south-west before Europeans arrived, and Nyoongar burning would have been most frequent close to such tracks and creeks, so maintaining a relatively fine mosaic. Further out, the mosaics were most likely coarser. We can learn from the traditional custodians of the land, by burning often along tracks and creeks.
These fires would have been mild and patchy, leaving plenty of refuge for animals, and that minority of native plants which cannot stand frequent burning. With generally mild burning, rocky areas, and moist or shady areas would have been protected from fire. Nature has a better capacity for organising itself than some can understand.
There is a branch of mathematics known as Knot Theory. Below I show a mosaic developed using Knot Theory.
Such a mosaic would not be difficult to establish along a creek or track in the bush. Once established, the patches could be burnt at any cyclic interval, from biennially up to the number of patches in the mosaic. Those interested in art may see a resemblance to the traditional Indian art form known as rangoli, or kolam. Others may see the wagyl serpent. Fire, art, and mythology are closely entwined.
Interestingly, bushfire mosaics have a fractal quality, in that each burnt patch can be, in itself, a mosaic of second-order burnt and unburnt, due to the presence of rocks, moist, shady places, southerly aspect, animal diggings etc. This second-order mosaic will be most pronounced when fires are frequent and mild, in low fuel. It will disappear when long fire exclusion and heavy fuel loads create large, fierce fires, and total burnout. Some firefighters refer to this as the Hiroshima effect.
A good example of the Hiroshima effect, due to heavy fuel, was at Mt Cooke a few years ago. There are others, notably in National Parks, where long fire exclusion has been attempted. Due to an ecologically inept fire policy, King’s Park bushland has been ravaged by two fierce fires since 1980.
In Africa, cattle people and hunters have long burnt in a mosaic pattern, to get rid of ticks, and bring up fresh feed. Kruger National Park burned fiercely in 2001, due to ill-advised attempts at fire exclusion. Twenty humans were killed, plus large animals such as elephant and rhino. In 1988, Yellowstone National Park burned fiercely for the same reason. Information on these fires can be found on the internet.
By bidi burning, we could protect hills suburbs from future uncontrollable bushfire. It would definitely help two iconic plants, the balga (Xanthorrhoea preissii) and the djiridji (Macrozamia riedlii). Both benefit from ash. After fire, the balga flowers, and the djiridji produces cones, then the red nuts known as byoo, an important food for Nyoongar people, who knew how to leach the poison out.
I hope DEC, FESA, and Volunteer Bushfire Brigades, will consider the merits of bidi burning. Much of it can be done, quite safely, in winter. As fuels are reduced, we could return to the summer burning used by Nyoongars, allowing fires to trickle on, in a friendly, self-organizing fashion, until the autumn rains. It would be cheaper, and we would see more kangaroos and wildflowers. Vandals would be completely baffled.