Fire, Fire Burning Bright

Australia is a land that burns, as it has for millennia, shaped by fire-loving trees and human hands.

Australia is a continent shaped by fire. Long before the first people arrived one tree, the eucalypt, rose to dominate the landscape and create the conditions in which fire became the signature of the land.

In his masterpiece Burning Bush: A Fire History of Australia, Stephen Pyne calls the eucalypt the universal Australian: “Found virtually nowhere outside Australia but, within Australia, found virtually everywhere.”

Here there would emerge a powerful alliance, “a triumvirate that eucalyptus formed with fire and the genus Homo”.

During an era Pyne called “the Great Upheaval” the continent dried as aridity became the norm and humidity the exception. The eucalypt was well placed to thrive. It had deep roots and foraged widely. It could hoard nutrients and store them for up to a decade. When drought came it could tough it out. It could grow where other trees starved.

“But if the eucalypt animated the bush, fire animated the eucalyptus.”

The tree is a pyrophyte, built to endure fire. At its base there are swollen woody organs called lignotubers that act as protected reservoirs of living tissue. They store carbohydrates and nutrients and sit insulated beneath the soil, ready to drive new growth even if every branch above ground is scorched. Many eucalypts also shelter epicormic buds beneath their bark. This is the tree’s dormant memory of itself; when the bark burns, these buds drive fresh shoots up the trunk.

“The eucalypt forest became a fire forest,” Pyne writes. “The eucalyptus could capture nutrients released by fire. Bark was thick and tough and it shed as it burned like the ablation plates of a descending spacecraft. If branches were seared off new ones could sprout from beneath the protected layer. If the bole burned, new trunks could spring from beneath the buried lignotuber.

“For most eucalypts, fire was not a destroyer but a liberator.”

Then, 60,000 years ago, the first people came, carrying their own deep, symbiotic relationship with fire.

“The bush was perhaps too dominated by eucalyptus and eucalyptus perhaps too closely reliant on fire and, through fire, on Homo. The eucalypt was less a pyrophyte than a pyrophiliac: fire became a near addiction with its own peculiar perils.”

By the time the first Europeans arrived Pyne says, “the structure of the forest reflected tens of millennia of Aboriginal fire”.

Virtually the entire landscape of Australia was, as archaeologist Josephine Flood concluded, “an artefact created by Aborigines with their fire sticks”.

When English explorer James Cook encountered Australia’s east coast, his logbook records: “At noon on Sunday, 13 May, 1770 we were between three and four leagues from the shore, the northernmost part of which bore from us N13W, and a point, or headland, on which we saw fires that produced a great quantity of smoke. To this Point I gave the name of Smokey Cape.”

Fire has been scorched into the records of Australian summers ever since and the most eloquent report on one dark chapter is the royal commission into the Victorian bushfires that burned from December 1938 to January 1939.

Coming at the end of a long drought, fire burned two million hectares and killed 71 people. The worst day came on January 13 and would be dubbed Black Friday.

On that day the commissioner, judge Leonard Stretton, wrote that “it appeared that the whole State was alight. At midday, in many places, it was dark as night. Men carrying hurricane lamps worked to make safe their families and belongings. Travellers on the highways were trapped by fires or blazing fallen trees, and perished. Throughout the land there was daytime darkness.”

These fires, he concluded, were lit “by the hand of man”.

“It is not suggested that the fires of 1939 could have been prevented, but much could have been done to prevent their spread and attaining such destructive force and magnitude,” Stretton wrote. Had “preventive burning been employed … such spread would have been retarded and such destruction would have been avoided”.

Stretton worried that “townships have been allowed to be encroached upon by scrub” and urged that “fire prevention must be the paramount consideration of the forester”.

“There is only one basis on which that policy can safely rest, namely, the full recognition by each person or department who has dominion over the right to enter the forests of the paramount duty to safeguard the property and rights of others. No person or department can be allowed to use the forest in such a way as to create a state of danger for others.”

As bushfire season returns there is much talk of conditions worsening with climate change. That may well be true, but the deeper truth of Australia is that our safety has always begun with how we manage the land.

As Stretton concluded, fires cannot be prevented but their worst effects can be mitigated through vigilance, good planning and sound land management.

As Pyne notes, two truths govern fire: “The more fuel the more vigorous the fire; the more wind the more rapid its spread.” We cannot dictate the wind but we should at least understand, and try to limit, the threat posed by fuel load.

Mark Adams was a member of the expert panel that assisted the 2009 Victorian Bushfires Royal Commission. He is blunt in his assessment of where we need to focus our mitigation efforts.

“As every person of Aboriginal descent, gardener, bushwalker and boy scout knows, dead leaves on the floor of eucalypt forests are highly flammable, accumulate quickly, burn fiercely, and physics dictates they are the crux of the Australian bushfire problem,” Adams told this column.

Yet Adams says much of Australia’s fire policy now rests on a model of leaf litter born in the 1960s, inspired not by ecology but by nuclear physics. It assumes that litter accumulates in a neat curve until it reaches a stable limit, like radioactive decay.

Adams has shown this is dangerously wrong.

His fieldwork, and that of others around the world, shows no such balance exists. Litter varies wildly with every hectare, every season, species and fire history. It never settles into a predictable, uniform state.

But because the model is simple and convenient, it has become embedded in the software and hazard maps used to determine fuel loads and shape hazard-reduction programs. This leads to false assumptions about risk and leaves communities exposed.

Mark Adams was a member of the expert panel that assisted the 2009 Victorian Bushfires Royal Commission. He is blunt in his assessment of where we need to focus our mitigation efforts.

“As every person of Aboriginal descent, gardener, bushwalker and boy scout knows, dead leaves on the floor of eucalypt forests are highly flammable, accumulate quickly, burn fiercely, and physics dictates they are the crux of the Australian bushfire problem,” Adams told this column.

Yet Adams says much of Australia’s fire policy now rests on a model of leaf litter born in the 1960s, inspired not by ecology but by nuclear physics. It assumes that litter accumulates in a neat curve until it reaches a stable limit, like radioactive decay.

Adams has shown this is dangerously wrong.

His fieldwork, and that of others around the world, shows no such balance exists. Litter varies wildly with every hectare, every season, species and fire history. It never settles into a predictable, uniform state.

But because the model is simple and convenient, it has become embedded in the software and hazard maps used to determine fuel loads and shape hazard-reduction programs. This leads to false assumptions about risk and leaves communities exposed.

Adams says the job of being an ecological scientist has been changed by the availability of computing power. The modelling culture, which seems to infect every aspect of modern life, has displaced the hard, slow work of science. To measure litter properly takes days of work for a single site and decades to compile enough data for each forest type. To build a national picture takes hundreds of person-years. State land management agencies once did this work but abandoned it in the 1990s. Today, fuel loads are often assessed visually or simply inferred from ageing models.

The consequences are serious and the clearest example is in NSW. There the Rural Fire Service’s fuel reduction burning is built almost entirely on fuel-load maps based on the assumption that every forest type has a single litter limit, supposedly reached within 20 years and unchanged after that.

Adams says this is dangerously wrong. No eucalypt forest is uniform. Litter, biomass and species mix can vary tenfold over short distances, largely shaped by the irregular legacy of past fires. The idea that fine fuels stop changing after two decades is equally absurd. If the underlying maps are wrong, and grow more wrong with time, then they are a flimsy defence against fire.

Adams argues that Australian fire science is decades behind where it should be and sliding fast. Research funding structures reward conformity. Serious researchers are sidelined unless they align with the dominant ideas of agencies. Modelling dominates because it is cheap, rapid and publication-friendly. Observation, the bedrock of science, is neglected.

This is a land that burns. For as long as humans have walked it, it always has. Climate shapes the weather, but fuel shapes the fire. We neglect this abiding truth at our peril.