Australia's Worsening Bushfires Trace Back to Colonial-Era Land Change

Keypoints:

• A Nature study reconstructs 1,000 years of vegetation and fire in Croajingolong National Park, East Gippsland
• The University of Melbourne team worked with the Gunaikurnai Land and Waters Corporation
• Charcoal analysis shows cool cultural fires replaced by hot wildfires after colonization
• The decisive break in the record falls around 1867
• The authors say restoring cultural burning is essential to lowering fire risk

Researchers at the University of Melbourne say the roots of Australia's bushfire crisis go back to the colonial era. Their study, published in Nature on 7 October, was done with the Gunaikurnai Land and Waters Corporation. It covers 1,000 years of vegetation, fire and erosion in Croajingolong National Park, one of southeastern Australia's most fire-prone forests.

Lead author Professor Michael-Shawn Fletcher says the findings support the value of cultural burning. Before British colonization, Indigenous people lit small, regular fires. These protected some areas from burning and encouraged new growth in others for animals to eat. A 2022 team that included Fletcher used pollen records to show forests were more open and grassy before colonization.

The new study adds fire temperature. Infrared analysis of charcoal preserved in sediment shows cool cultural fires in the pre-colonial period. After colonization, hot wildfires replaced them. Change-point analysis places the decisive break at around 1867, when the Gunaikurnai were displaced from their Country.

The plants explain the shift. Eucalyptus trees sprout rapidly after a blaze clears competing plants. Without regular cool fires, dense stands formed and created continuous fuel. Their oil-rich leaves burn readily, and climate warming amplifies the risk.

The authors conclude that restoring cultural burning, and supporting Traditional Owners to care for Country, is an essential part of reducing wildfire risk. The study also challenges the idea of wilderness as land untouched by humans. In this record, the landscape was managed. Fire policy built on suppression alone may need a longer memory.