Bushfires spark extensive search for answers
Box 3 | Other burning issues
Fire has been part of the Australian landscape for thousands of years: with bushfires sparked by lightning or started by Aboriginal groups as part of their hunting and land management practices.
An important factor in tracking the effects of fire on the environment is whether the bush undergoes a single fire or repeated burns, what’s known as a fire regime.
A fire regime can involve not just the frequency of fires in a particular area, but also the seasons when the fires occur, how big an area is burned and the intensity of the burn.
The effects of fire in regenerating the bush can be dramatic. Immediately after a bushfire, the landscape might be charred and barren, completely black and seemingly devoid of life.
Yet maybe only a few months later, the bush is re-born. Bushes and trees have begun to re-sprout and flower, and seeds that have been released and germinated by the blaze are taking root. Animals and invertebrates return to adapt to the changing landscape and begin a new life cycle.
Over the centuries, many Australian plants have evolved to survive this cycle of fire in the bush, such as eucalypts, which rely on fire for regeneration. Not only does the bark of eucalypts offer insulation and protect the tree, a fire can result in trees growing new shoots along their branches.
Other plant species that have adapted to or rely on fire to some degree include the xanthoria (grass tree), wattle and banksia.
A key goal of the various research programs into the effects of bushfires is developing techniques to sustainably manage the environment.
A major consideration is determining the main land use – whether it be forestry, conservation, national parks, pastoral or rural communities – and how the area’s wildlife and flora fit in with this predominant land use. A growing concern is urbanisation, and how many suburbs are spreading to the very edge of the bush as people seek a home or property within a bush setting.
Also critical is the fuel load of the area being considered – basically the vegetation or biomass that feeds the flames – which can be measured in several ways. These include:
- Harvesting a sample area, drying the vegetation, and then weighing it (to get a figure in, say, tonnes per hectare);
- Remote sensing to collect images via satellite and analysing the photos to determine vegetation cover; and
- Indirect methods such as precipitation and rainfall data to estimate end-of-season biomass figures.
Boxes
Box 1. Fire in the tropical savannas region
Box 2. Fire in the Australian Alps
Related sites
The research program (Bushfire CRC, Australia)
Bushfire research (Ensis, Australia)
Understanding bushfire behaviour (CSIRO, Australia)
Fire fundamentals: Fire regime
(Fire ecology and management in Northern Australia, Australia)
Effects of fire on plants and animals: Individual level
(Fire ecology and management in Northern Australia, Australia)
Posted January 2008.