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1997....good science reference for John Benson, Royal Botanical Gardens Sydney

There is considerable controversy and debate regarding the use of fire in pre-European Australia. Many articles have been written claiming that the vegetation was continuously burnt by a combination of natural and human factors. The following abstract represents a recent informed opinion.

One respected academic in this area is John Benson of the Royal Botanic Gardens Sydney:

Abstract from "The nature of pre-European native vegetation south-eastern Australia" (condensed from J.S. Benson and RA. Redpath, Cunninghamia, 5(2) December, 1997)

"Based on a selection of quotes from early European explorers and settlers, it has been suggested that, at the time of European settlement of eastern Australia: the vegetation was mainly composed of grassland and grassy woodland; that Aborigines burnt most of the country every year or so; and a lack of fire after European settlement led to thick regrowth that was subsequently ringbarked and cleared by settlers for agricultural expansion. This overlooks the extensive scientific literature on past and present vegetation, and on fire ecology in Australia.

The claims of frequent burning mainly cover parts of south-eastern Australia between Tasmania and Brisbane, but do not deal with particular regions in a systematic way. They generally refer to one type of vegetation formation grassy woodland, which mainly occurs on clayey soils in drier coastal valleys, on non-siliceous soils on the undulating tablelands and on the western slopes. The explorers may have favoured travelling through these areas because they occur near rivers (water), had an open understorey and because some explorers were employed to seek out suitable grazing lands.

Using three historical estimates of tree density in grassy woodlands, we estimate there was an average of 30 large trees/ha spaced about one tree width apart. We found frequent references in the explorers' journals to vegetation containing a dense understorey including coastal heath, shrublands, rainforest and dense eucalypt forests. We found no evidence that most of south-east Australia's vegetation was annually burnt by Aboriginal people and provide examples where explorers' notes about fire have been misinterpreted or inappropriately extrapolated.

While some journal entries reveal that Aboriginal people used fire for cooking and burning the bush, the extent, frequency and season of their use of fire is largely unknown, particularly for southern Australia. Vegetation types such as rainforest, wet sclerophyll eucalypt forest, alpine shrublands and herbfields, and inland chenopod shrublands, along with a range of plant and animal species, would now be rarer or extinct if they had been burnt every few years over the thousands of years of Aboriginal occupation.

Furthermore, much evidence has been ignored that points to climate as being the main determinant in vegetation change over millions of years, with major changes occurring since the onset of aridity in the Miocene ( 24 to 5 million years ago) but continuing through the last ice age, which coincided with the occupation of Australia by Aboriginal people.

The adaptation of many plant species to aridity, drought, low nutrient soils and fire does not imply a requirement for them to be frequently burnt. South-eastern Australia's native vegetation is now highly fragmented, after 200 years of clearing, stock grazing and weed invasion. Management of what remains of this vegetation should be based on a scientific understanding of the functioning of ecosystems and the population dynamics of a range of plant and animal species."
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