Sediment cores from a lake in southeastern Australia have provided a detailed window into more than a millennium of landscape history. The findings, published in the journal Nature, indicate that frequent, low-intensity burning by the Gunaikurnai people kept woodlands open and stable for centuries before British colonization began in 1788. Those practices ended in the 1840s, setting the stage for denser, more flammable vegetation long before recent climate trends intensified.
Stable Woodlands Under Longstanding Care
For more than 800 years before European settlement, the Gunaikurnai maintained open eucalypt woodlands through regular cool burns. Tree cover remained low, averaging around 10 percent across the study area in East Gippsland. High-temperature fires that reach the canopy were rare, and soil stayed protected by ground vegetation. This pattern produced a landscape that resisted the kind of intense blazes seen in later decades. The consistent application of cultural burning limited fuel buildup and preserved the structure of the woodlands. Researchers note that the approach reflected a deep, ongoing relationship with Country rather than sporadic intervention.
Clear Break After Colonization
The record shows a sharp change once Indigenous management was disrupted in the 1840s. Without regular cool burns, woody material accumulated on the forest floor. Eucalypt cover, which is naturally oily and flammable, rose to roughly 34 percent by the 1970s. The shift produced more high-temperature charcoal in the sediments, with levels doubling or tripling compared with earlier centuries. These particles signal crown fires that consume the canopy and strip away protective ground cover, leaving soil exposed to erosion. The transformation occurred well before widespread industrial-era warming.
Lessons From the Sediment Layers
Cores taken from Purghagoolah, also known as Lake Elusive, captured both pollen and charcoal particles that track vegetation and fire intensity over time. The data reveal a consistent baseline of low tree density and mild fire activity that held steady until the mid-19th century. After that point, the indicators move together: rising tree cover, heavier fuel loads, and evidence of hotter fires. The sequence demonstrates that fuel accumulation alone can drive greater fire severity even in the absence of strong climate forcing.
- 800+ years of stable, low-intensity burning before 1788
- Tree cover roughly quadrupled after management ended
- High-temperature charcoal increased markedly in the colonial era
- Changes preceded modern climate-driven warming
Broader Context for Fire-Prone Regions
The study underscores that historical land-use decisions can shape fire behavior for generations. In this case, the removal of Indigenous stewardship created conditions that made severe fires more likely once ignition sources appeared. Ongoing efforts to reintroduce cultural burning in parts of Australia draw directly on these long-term patterns. The sediment evidence supplies a baseline that helps separate the effects of vegetation change from those of temperature and drought trends. The findings add weight to calls for integrating traditional knowledge into contemporary fire management. They also illustrate how one region’s record can inform understanding of similar challenges elsewhere.
