Open Access

Paul Foreman

• The functional relationships between woody vegetation, climate, soils and disturbances like fire are complex and vary greatly between continents due to historical and environmental differences. In the temperate grasslands of lowland south–eastern Australia, it is hypothesised that the extent of treelessness was influenced by Aboriginal burning practices, although this remains highly contested. This study reconstructed a multi–bioregional–scale grass/ tree boundary map across a large portion of central and northern Victoria from hundreds of historic plans, overlayed with the georeferenced observations of the earliest European accounts to test whether these grasslands were (a) more extensive than previously assumed, and (b) if there is evidence of the targeted, purposeful and frequent use of fire by Aborigines. The archival coverage was well–corroborated and identified extensive treeless 'plains' in unexpected areas compared with reconstructions based on climate–edaphic relationships alone. The historic accounts also served to shed light on the original nature of these treeless 'plains' as diverse and dynamic, and frequently dominated by Kangaroo Grass (Themeda triandra), implying a distinct influence of both frequent fire and people. However, while there is evidence of broad–acre Aboriginal fires in the collective historic accounts (including resistance to European intrusion), there remains a need for more in–depth and reliable historic case studies to clearly describe the use of fire by Aborigines that is inferred in the historic accounts studied here and commonly assumed by historians. The results lend support to treelessness driven by the dynamic interaction of 'bottom–up' and 'top–down' processes and that lowland temperate grassland distribution reconstructions across this region should be extensively corroborated or even derived exclusively from historic sources.