British colonisers thought they were protecting forests by stopping Indigenous burning. It’s now backfiring

Alterations made to Australia’s forests during British colonial rule have amplified the effects of climate change and rendered the country more prone to bushfires, a new study suggests.

The research provides evidence for the value of cultural burning by Indigenous communities, scientists from the University of Melbourne say.

“Climate records show seasons of comparably dangerous fire weather such as those seen during Ash Wednesday and Black Saturday reoccurred in the region repeatedly before colonisation, yet the open landscape maintained by cultural burning protected the land from catastrophic fire,” Michael-Shawn Fletcher, an author of the new study, said.

“When colonisation ended that care, the forest expanded and thickened across the region, loading the landscape with fuel. It is that transformation that has handed control of fire to climate.”

The study, published in the journal Nature, reconstructed the last 1,000 years of vegetation, fire and erosion in the Croajingolong National Park, East Gippsland, one of the most fire-prone forests in the southeast.

It showed that British colonisation of the continent, beginning in 1788, saw a fourfold increase in eucalyptus tree cover and transformed the landscape from open woodland to forest.

These changes predate human-driven climate change and demonstrate that the current vulnerability of southeastern Australian eucalypt forests to wildfire is strongly influenced by colonial land-use legacies.

“Most discussion of Australia’s wildfire crisis stops at climate change,” Dr Fletcher said.

“Our work shows what set the stage for it – forest expansion and thickening that loaded the landscape long before the climate began to shift.”

Researchers analysed lake sediments for preserved charcoal to measure historical fire temperatures. They found that cool fires from cultural burning in the pre-colonial era were replaced by hot wildfires after.

The hot fires drove a fourfold surge in eucalypts that thickened the once-open woodland into forest and loaded the landscape with more bushfire fuel.

The findings suggest that restoring cultural burning and supporting traditional owners to care for the country is an essential component of mitigating wildfire risk in the future, Indigenous leaders say.

Gunaikurnai elder Uncle Russell Mullett said their ancestors were born with towera, or fire. “Not treating country with towera,” he noted, “country becomes extremely dangerous for Gunaikurnai, animals, and plants.”

“Studies such as this provide firm scientific evidence to support towera land management initiatives for country,” he added.