Indigenous cultural burning has protected Australia's landscape for millennia, study finds

The research, published in Science, highlights how the intensity of forest fires in fire-prone southeastern Australia decreased over time alongside an increase in Indigenous populations in the area.

Dr Simon Connor from ANU said a better understanding of the link between human-induced climate change and the projected rise in the frequency and intensity of forest fires will lead to improved forest management and conservation in Australia.

"We often think about forests and woodlands in terms of trees, but this research shows that some of the biggest changes have happened not in the tree canopy but in the shrub layer. That's something we weren't expecting to find," he said.

"Indigenous peoples have shaped Australian landscapes over tens of thousands of years. They did this through cultural practices. We need to keep that in mind when we're thinking of the best way to live in the Australian environment."

Using tiny fossils preserved in ancient sediment, the research team reconstructed ancient landscapes across southeastern Australia to understand how the vegetation has changed over time.

The researchers focused on the shrub layer because this is what allows flames to climb from the ground to the canopy, leading to high intensity fires.

The team then compared this with archaeological data to analyse how human activity has impacted levels of shrub cover in Australian landscapes over time.

Lead researcher Dr Michela Mariani, from the University of Nottingham, said the expansion of Indigenous populations and a subsequent increase in the use of cultural burning led to a 50 per cent decrease in shrub cover, which in turn led to a decline in high intensity fires.

"The shrub layer in forests can often act as ladders for wildfires to climb up to tree canopies and spread," Dr Mariani said.

"Following British colonization and extensive fire suppression, shrub cover in Australia has increased to the highest ever recorded, which significantly increases the risk of high intensity fires in the future.

"Australia's fire crisis can be tamed with the involvement of Indigenous practitioners in fire management. It's important to rekindle ancient cultural burning practices together with Traditional Owners to reduce the risk of catastrophic blazes."

This work also involved researchers from the University of Melbourne, Monash University and the University of Tasmania.