Colonial land use left southeastern Australia’s forests denser and more fire-prone

A 1,000-year record suggests the disruption of Gunaikurnai burning practices changed forests before human-caused warming.

Abstract editorial illustration accompanying the article: Colonial land use left southeastern Australia’s forests denser and more fire-prone

Editorial illustration — not from the study.

Researchers reconstructed 1,000 years of vegetation and fire history in a temperate eucalypt forest in southeastern Australia using lake sediments. Before British colonization from 1788, frequent, small-scale, low-temperature burning by the Indigenous Gunaikurnai people was associated with stable, open woodlands.

After colonial disruption of these practices, the record shows hotter fires, a fourfold increase in eucalypt cover, a shift from open woodland to forest and increased soil erosion. The researchers say these changes created a more flammable landscape, amplifying the influence of climate change and contributing to a reinforcing cycle in which intense fires increase fuel loads and the risk of later fires.

How the forest changed

Before 1788, frequent, fine-grained, low-temperature cultural burning by the Gunaikurnai people maintained relatively stable open woodlands. Following colonial disruption, fire temperatures increased, eucalypt cover rose fourfold, and the landscape shifted from open woodland to denser forest. Soil erosion also increased. These changes came before anthropogenic warming, according to the 1,000-year record.

Why past land use matters

The findings indicate that climate change is not the only historical influence on wildfire risk in these forests. Colonial land-use changes helped create denser, more flammable vegetation, which may have amplified the effects of a warming climate. The researchers argue that restoring resilience will require integrating Indigenous knowledge into fire management.

Evidence and caveats

The study is based on a 1,000-year lake-sediment record from a temperate eucalypt forest in southeastern Australia, using past vegetation and fire signals to reconstruct environmental change. The abstract describes evidence from this forest, so the findings cannot by themselves establish how widely the same pattern applies across Australia or quantify colonial land use’s contribution to current wildfire activity. The record also shows the timing and sequence of past changes rather than directly testing present-day fire-management interventions.

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