07 October 2026
The suppression of Indigenous burning practices probably spurred the growth of flammable forests.
The suppression of Indigenous burning practices in Australia after British colonization probably transformed swathes of the southeast into dense, flammable forests that contribute to bigger, hotter bush fires today, according to a reconstruction of fires in the region over the past 1,000 years published in Nature1.
The researchers suggest that restoring Indigenous approaches to forest management could lower the risk of devastating fires, particularly as the climate warms. “It gives us another variable when we’re trying to tackle this problem, rather than just focusing on climate change,” says Michael-Shawn Fletcher, a Wiradjuri scholar and palaeoecologist at the University of Melbourne, Australia.
The team set out to understand why southeastern Australia is experiencing larger, more-destructive fires, such as the unprecedented Black Summer fires in 2019–20, which burnt more than 8 million hectares of land of forest in that region.
In 2022, a team that Fletcher was part of used pollen records to show that forests in the region tended to be more open and grassy before British colonization at the end of the eighteenth century2. Soon after the colonization, forests changed, says Fletcher. “You can see right across the landscape there was an increase in woody fuels following the British invasion,” he adds.
A millennium of wildfire
To investigate this pattern in more detail, Fletcher and his colleagues collected a sediment core from a lake at the southeastern tip of Australia in Croajingolong National Park, part of the traditional lands of the Gunaikurnai people. Reconstructions of the landscape as well as historical evidence show that they regularly burnt the land until their violent removal by the British in the mid-nineteenth century.
Like in the 2022 work, the researchers analysed pollen in the extracted sediment to reconstruct the make-up of plant species and the structure of the surrounding forest over the past 1,000 years. This record showed an open woodland, with grasses and few trees for 800 years. Then, around 1840, the researchers found that the coverage of eucalyptus (Eucalyptus spp.) had doubled and woody shrubs had spread across the area.
The team also analysed charcoal in the sediment to estimate the temperature of fires over the study time frame. They identified molecules produced by burning plants at different temperatures in the laboratory, then searched for those molecules in the sediment samples. They found an increasing fraction of high-temperature charcoals from the mid-nineteenth century onwards, suggesting more-intense fires.
The researchers say that the changing vegetation and fire regime are linked: hotter fires spur the growth of more-flammable vegetation, more fuel and a denser canopy, creating what they call a “catastrophic wildfire loop”. Eucalyptus trees rapidly sprout after a blaze clears out other competing plants, says Fletcher.
The authors attribute this change to the end of regular, small fires ignited by Indigenous people to protect certain areas from burning or to promote vegetation growth in other areas for animals to eat.
Wildfire loop
The idea of a feedback loop is “compelling”, says Christy Briles, a palaeoecologist at the University of Colorado Denver. However, she says that more sites need to be studied to understand how common the pattern is across southeastern Australia.
Others recognize this dynamic beyond Australia. “This is very convincing in my opinion,” says Clay Trauernicht, an ecologist at the University of Hawaii at Manoa. He adds that the change in wildfires seen at the lake is similar to that in other regions where Indigenous management was replaced with management oriented towards private property, such as Hawaii and the western United States.
There have been some efforts to restore cultural burning and other Indigenous management practices in southeastern Australia. But Fletcher says they have been too small and infrequent to have much effect.
As temperatures continue to rise and the planet warms, more frequent, low-temperature burns might reduce the chance of later, out-of-control fires, says Fletcher. “We need landscape-scale experiments to test these things before it’s too late,” he says.
doi: https://doi.org/10.1038/d41586-026-03184-y
References
- Fletcher, M.-S. et al. Nature https://doi.org/10.1038/s41586-026-11097-z (2026).
- Mariana, M. et al. Front. Ecol. Environ. 20, 292–300 (2022).
