According to Tim Flannery’s Climate Council, Aborigines ate the megafauna, so highly flammable scrub grew up and they had to develop hazard reduction burning. Then the Industrial Revolution changed our climate so that it’s impossible to do mild burning, and now we get extreme weather that creates unstoppable megafires.
On the other hand, according to Scott Mooney and eighteen other scientists, Aborigines had no effect on Australian fire regimes which varied according to the climate in Greenland (this is not a typo) as evident in ice cores. They say that more biomass burnt in warmer periods and human influence on fire regimes began after Europeans arrived in Australia.
Objective scientific analysis of the relevant data reveals that both views are incorrect.
The highest levels of biomass burning in 70,000 years occurred at the time that Aborigines proliferated across Sahul (Australia, New Guinea and Tasmania) about 40,000 years ago. There was a trend of increasing charcoal deposition with decreasing temperature in Antarctica, that is increasing aridity in Australia, between 50,000 and 40,000 years ago. Aboriginal burning extended open grassy vegetation at the expense of dense woody vegetation, eliminating megafaunal browse. It created ecosystems that depend on mild burning to maintain their health and biodiversity.
After this, there was a steep decline in charcoal as ice sheets developed in the lead up to last glacial maximum about 20,000 years ago. Then there was a fairly steady rise in temperature and charcoal deposition until massive rises in sea-level separated our mainland from New Guinea and Tasmania about 10,000 years ago. Rainforest started to reinvade the Atherton Tableland when it became too wet for people to burn about 9000 years ago. Then there were peaks and troughs in charcoal from infrequent high-intensity fires over a couple of thousand years until eucalypts died out. Charcoal deposition declined to very low levels.
Aborigines died out after Kangaroo Island was cut off from the mainland about 4000 years ago. Charcoal spiked and casuarina woodland turned into wattle scrub. Dense eucalypt forest developed over a millennium. The charcoal record indicates infrequent high-intensity lightning fires since then, and Matthew Flinders’ observations in 1802 of large dead trees and fallen logs amongst dense regrowth confirm this.
When Europeans disrupted Aboriginal burning, woody thickening choked out biodiversity and created heavy three-dimensionally continuous fuels that inevitably explode in megafires during severe weather. In 1851, before any industrial impacts on our climate, 5 million hectares of Victoria were destroyed by the Black Thursday fires. Post-European fires produced unprecedented quantities of charcoal in the 70,000 year sedimentary record, indicating huge burning of biomass. After foresters re-introduced broad-scale mild burning from the mid-20th Century, there was a pronounced decline in charcoal deposition against a warming trend.
Green ideology has brought a reduction in mild burning since the late twentieth century, and caused an explosion of pestilence and megafires. Black Summer incinerated eight million hectares of native forest in southeastern Australia and killed countless millions of native animals. Thirty-three people were killed and 3,100 homes were destroyed. Massive increases in charcoal deposition are yet to be sampled in sediment cores and reported in the literature.
The palaeological and historical data through tens of thousands of years of climate change clearly show that people have had the overriding influence on fire regimes since they arrived in Australia, except where it became too wet to burn or too cold and dry to sustain woody vegetation. We can reinstate resilient, healthy and safe landscapes irrespective of climate change. Governments need only listen to experienced land and fire managers, black white or brindle, rather than green academics with wilderness between the ears.
Vic Jurkis is a former NSW Forestry Commission professional forester, Officer in Charge of the Forestry Commission’s Regional Research Centre at Eden, the Forestry Commission’s Regional Planning Manager at Eden and Silviculturist for the Commission’s Native Forest Division, responsible for forest management across the State. In 2004 he was awarded a Fellowship by the Joseph William Gottstein Memorial Trust, to investigate eucalypt decline across Australia. He has published two books, Firestick Ecology, and The Great Koala Scam, both available from Connor Court.
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