MELBOURNE, Oct. 8 (Xinhua) -- Forest expansion and thickening after British colonization created landscapes more prone to burning, amplifying the influence of climate change and propelling Australia's bushfire crisis, new research finds.
Researchers from the University of Melbourne, in collaboration with Gunaikurnai Land and Waters Aboriginal Corporation, reconstructed the past 1,000 years of vegetation, fire and erosion in Croajingolong National Park, one of southeastern Australia's most fire-prone forests, according to a university statement released on Thursday.
Published in Nature, the study found that colonization drove cascading changes, including increased fire temperatures, a fourfold increase in eucalypt cover, the transformation of open woodland into forest and increased soil erosion.
The findings provide scientific evidence for the value of cultural burning and the need to integrate Indigenous knowledge into contemporary fire management, said lead author Michael-Shawn Fletcher, a professor at the university.
Climate records showed similarly dangerous fire-weather seasons had repeatedly occurred before colonization, but cultural burning helped maintain open landscapes and limit catastrophic fires, Fletcher said.
"When colonization 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," he added.
Researchers found that the land-use changes predated human-driven climate change, indicating that the current vulnerability of southeastern Australia's eucalypt forests to wildfire has been strongly influenced by colonial land-use legacies.
Sediment records showed that hot fires were followed by a fourfold surge in eucalypts, thickening the landscape and increasing fuel loads. Infrared analysis of charcoal showed that cooler or low-intensity cultural fires before colonization were replaced by hot wildfires afterward. ■
