Using the Paleorecord to Evaluate Climate and Fire Interactions in Australia

Burning has been a near-continuous feature of the Australian environment but has become progressively more important since the mid-Tertiary, associated with the development of the characteristic sclerophyll vegetation. In the Quaternary, the extent of burning has varied temporally and regionally with glacial-interglacial cyclicity. Burning during glacial periods was reduced in drier areas, presumably because of a critical reduction in fuel availability, but increased in relatively wetter areas where fuel levels were high. On both glacial and Holocene timescales, peaks in charcoal often accompany transitions between fire-insensitive vegetation types, suggesting that burning is facilitated during periods of climate change and environmental instability. This suggestion has been supported by the demonstration of close relationships between fire and El Niño activity. Burning has also increased progressively over the past few hundred thousand years with major accelerations around the time of first human settlement of the continent and with the arrival of Europeans. To provide a firmer base for application of paleofire records to environmental management, there is an urgent need for a spatially more-substantial coverage of high-resolution fire records with good chronological control.