Bushfires spark extensive search for answersThey can start with a momentary flicker, they can burn for months, and their effects can scar landscapes and lives for years.
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Key textBushfires are a natural and complex part of the Australian environment and have been for thousands of years. People as well as the natural environment have developed ways of coping with bushfires. Individuals and communities living in or near bushfire prone areas have established strategies to protect themselves and their homes from fires, these include removing all rubbish and leaf litter around buildings, implementing fire restrictions and preparing evacuation plans. While in the natural environment, many plants have evolved to adapt to, and cope with fires.Research is now underway on many fronts to determine not only how to prevent bushfires, but also gain further insight on their devastating effects. The areas being looked at include how repeated fires affect local communities, the environment and our native plants and animals, as well as the extra dangers brought about by climate change and drought. Turning up the heat In the summer of 2002-2003, raging fires burned through some four million hectares across five Australian States and the Australian Capital Territory. Hundreds of homes went up in flames, four residents caught in the infernos in Canberra were killed, and the damage to property and communities was incalculable. The environment was also extensively affected, with the fires raging through forests, national parks, reserves and farm land, killing stock and native fauna, and torching trees and other plants. When the smoke cleared, one scientist predicted that it would still take around 200 years for some parts of the nation's forests to fully recover. The official inquiry into the fires heard from some 500 people, and made nearly 60 recommendations on how Australians can better equip their communities to battle such catastrophic blazes. It also turned up the heat for researchers to come up with better information and ways to reduce fuel loads and lessen the effects on communities and the environment. That research is being carried out around Australia, with much of it involving the Bushfire Cooperative Research Centre (CRC), which was set up as the result of the 2001–02 fires in NSW. Managing the bush to save lives and towns One key area being looked at is the use of prescribed burns – how effective they are, and the effects of repeated burns on ecosystems. With prescribed burns, areas of bush are deliberately set alight in the cooler months with the aim of reducing the fuel loads, and thus helping to mitigate really big fires from arising. For instance, the Department of Environment and Conservation in Western Australia as part of its annual prescribed burn season, burns up to 100,000 hectares of the state's south-west forests. The department says prescribed burns also help maintain the biodiversity of ecosystems across the state, and rehabilitates vegetation after disturbances such as timber harvesting and mining.
But prescribed burning is a contentious issue. Not everyone believes that it is an effective land management tool. One concern is the effect of repeated burns on animal and plant species. It's believed that inappropriate fire regimes since European settlement have already been responsible for the extinction of two bird species – the Kangaroo Island emu and the northern scrub robin – as well as endangering many other bird varieties. However, in a number of cases, the occurrence of wildfires have also led to a drop in wildlife populations. The fires in 2005 and 2006, which took place in the Ngarkat Conservation Park in South Australia were damaging to the habitat and the populations of the already threatened Western whipbird and the Mallee emu-wren. Another key issue with the prescribed burns is how do we determine the best time between burns. A recent long-term study in parts of Kakadu National Park by the CSIRO raised concerns that overburning is leading to the disappearance of native wildlife species (Box 1: Fire in the tropical savannas region). The study suggested that some native populations needed to be fire-free for up to five years to ensure their long-term survival. While in Queensland, the Bushfire Management Coordination Group has developed a strategy that recommends a range of fire cycles of up to 20 years for differing forest regions. It suggests that in dry open eucalypt forests, in the absence of natural fires, controlled burns should take place from 7 to 12 years apart in developed areas; but in less developed areas, burns should take place at intervals varying from 7 to 20 years. Clearly, the fires will have an effect on the ecosystem, irrespective of whether or not they are man made. Research is required to identify the factors that determine whether this effect is positive or negative. In the Australian Alps, wildfires have an overall greater impact to the survival of Alpine ash forests than managed fires. However it is worthwhile to note that a burn regime of less than 30 years could wipe out Alpine ash forests (Box 2: Fire in the Australian Alps). The Alpine ash only produces seeds after it reaches maturity at an age of 30 years or more; fires occurring at a frequency of less than 30 years would therefore kill trees before they could produce seeds.
There are also however, examples in which the occurrence of fires actually help the regeneration of plants. The survival of the Mountain ash is dependent on the occurrence of fires. Mountain ash can only regenerate from seeds, and fire is essential to provide the right conditions for the germination of its seeds. But if fires occur before the young trees reach maturity and produce seed (50 years old), the species may be completely wiped out. The species may then be replaced by another species better adapted to cope with that specific fire regime. In another example, plant species like the eucalypts regenerate from lignotubers, which are stimulated by fire to develop shoots. And a study has found that smoke from burning plant material promotes seed germination in a variety of Australian plants. Studying the effects of prescribed burns
Australian researchers are looking at the ecological effects of repeated fires – either prescribed burns or wildfires – on the landscape over a period of 50 years. Satellite imagery is being used to help determine patterns of fire intensity and to help identify changes in the biota (the flora, fauna and microbes in the region) as a result of different fire regimes in forests across the south-west of Western Australia. Such research will give fire managers guidelines for the optimum frequency, season, intensity and extent of burning to better manage the land. Other researchers are looking at how prescribed burns affect the resilience or 'ecological memory' of the south-west forests: how long it takes to recover to its former state and how productivity of the land is affected. It's hoped the findings will be able to better protect forests and ecosystems.
CSIRO scientists are currently investigating the effects of fuel load and the long term effects of prescribed burning on the behaviour of wildfires in dry eucalypt forests, which are found in many areas of Australia. Sifting through the ashes How to best manage the use of fire in the landscape has become more urgent in Australia (Box 3: Other burning issues). The nation is already the world's driest inhabited continent, and it is undergoing prolonged drought exacerbated by climate change. It is likely that Australia will always have large fires, but with better land management and successful hazard reduction, the land and its people will be able to recover much more quickly from the trauma of fire.
Box 1: Fire in the tropical savannas regionThe tropical savannas region of northern Australia roughly covers 25 per cent of the country, stretching from Kimberley in Western Australia, across the Top End and through to Rockhampton in Queensland.Much of it is grassland, predominantly sorghum. Each year during the dry season from May to October, the grasses dry out and become fuel for extensive bushfires. These fires can burn for months across thousands of hectares, burning some 50 per cent of the savanna vegetation. The fires might burn with less intensity than those in forested regions of southern Australia, but they show up clearly on satellite images and stretch across the top of the continent like a patchwork of blazing mosaics. By some accounts, it’s estimated that the gases produced by these fires contribute two per cent towards Australia’s greenhouse effect. Fire management plays a big part in learning to live in this landscape, and has been part of local Aboriginal tradition for centuries. Several fire management projects are tapping into traditional Aboriginal practices to better manage the savanna regions. At Boggy Plain in Kakadu National Park, researchers are working with a local indigenous family to use traditional fire management techniques to help conserve the Ramsar-listed wetland. The wetland is burnt during November and December and again in April and May to control the rampant native grass (Hymenachne acutigluma). The grass has been spreading widely since the removal of the Asian water buffalos from the wetlands, which kept the grass in check in much the same way as the indigenous fire management did before European settlement. Other groups also use fire as a management tool in the tropical savannas, such as pastoralists trying to improve pasture for the cattle industry, and conservation managers. Developing effective and ecological fire management tools is complicated by factors such as the frequency of fires, the intensity of the burns, and in which part of the dry season a burn is carried out. One Kakadu study found that some fauna were better off than others, with lizards coping better in early dry season fires than kangaroos and wallabies. Overall, early burning had the least impact and is favoured as a management tool in the savannas. However, the fire management techniques mentioned are only applicable to the tropical savanna regions of Australia. The processes and principles involved in managing fires occurring in Tasmania, New South Wales and other regions of Australia vary greatly from those applied in the tropical savanna regions. Related sites
Box 2: Fire in the Australian AlpsMany people might think of the ‘bush’ as that mix of forests, reserves and unpopulated land that fringes our major cities. But Australia has some distinctive landscapes that require special consideration when it comes to managing fire.The high country area of south-east Australia which takes in New South Wales, Victoria and the Australian Capital Territory form the unique landscape of the Australian Alps. Following the 2002–03 fires which devastated this area of south-east Australia, the Federal Government allocated extra funding for research into managing fire in high altitude terrain. The Bushfire CRC HighFire research project is looking into how fires affect alpine and sub-alpine ecosystems and communities, providing scientific evidence to support practical and effective fire management practices. It is looking into issues such as fuel management, ecosystem functions, climate change factors and the flammability of the landscape. Amazingly, although the 2002–03 fires consisted of 185 fires which burned through some 1.8 million hectares, it wasn’t the worst fire to burn through south-east Australia. Researchers estimate it was the third largest fire in the region, after massive burns in 1851 and 1939. Apart from the normal factors contributing to the 2002–03 wildfires, there were extenuating factors. The Australian Alps National Parks body says Australia had been going through drought conditions and the effects of an El Niño cycle. The average rainfall for 2002 was the fourth driest since 1900, and temperatures were among the warmest recorded. Most of the Australian Alps is set aside as national parks but in addition to prescribed burns, a major issue for these alpine and sub-alpine regions has been the grazing of cattle and sheep. For some, there is a strong belief that ‘alpine grazing reduces blazing’: that grazing animals reduce the risk of fire by eating plant material that might otherwise go up in flames. However, research conducted by CSIRO scientists shows that cattle generally prefer the open grassy areas for grazing, rather than the heathlands that pose the bigger fire risk. And following the 2003 bushfires, researchers studying parts of the Bogong High Plains in Victoria, came to a similar conclusion. The researchers said that the ‘grazing reduces blazing’ theory might be attractive, but that it was an oversimplification. Following concerns about erosion and catchment issues, grazing was discontinued in what is now Kosciuszko National Park in New South Wales. And in Victoria, the cattle grazing licences in the Alpine National Park were not renewed after the last ones expired in mid-2006. Related sites
Box 3: Other burning issuesFire 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:
Activities
Further readingANU Reporter Spring 2007 The fires to come Investigates the link between global warming and the frequency of fires.
April 2005, pages 6-9 Living with fire Reports on study investigating the effects of bushfires on animals.
ATSE Focus December 2004 Shock factor – public perceptions of risk in science (by Julian Cribb) Looks at the public’s perception of risk.
Cosmos 9 February 2009 Wildfire ferocity linked to climate change Suggests that climate change will increase the frequency and intensity of bushfires in Australia and may have been implicated in the 2009 bushfires.
December 2005 Storms of fire (by Dan Drollette) Investigates whether the devastating bushfires seen in Australia could become more common elsewhere.
Ecos No. 124, 2005, pages 18-22 Reign of fire (by Julian Cribb) Looks at the effects of dry conditions on rainforests.
No. 117, 2003, page 5 Over-burning pressures Top End's biodiversity Reports that over-burning could damage biodiversity in Australia’s savanna bushland.
No. 115, 2003, pages 42-43 Lizards cool under fire (by Steve Davidson) Provides a snapshot into how lizards respond to a controlled burn.
No. 110, 2002, page 35 Clear-fell versus fire (by Steve Davidson) Questions whether clear-fell harvesting is ecologically sustainable and conserves biological diversity.
No. 109, 2001, page 3 Red alert for red-eyed pigeons (by Wendy Pyper) Looks at effects of fires on the savanna understorey and partridge pigeons.
No. 107, 2001, page 35 Fire cues for seed germination (by Steve Davidson) Study reveals exposure to smoke promotes seed germination.
No. 100, 1999, page 3 Fire - finding the best prescription (by Alastair Sarre) Explores the impact of forest burns on Australia’s forest ecology.
The Helix December 2003-January 2004, pages 9-16 Bushfires: Preventing a natural disaster (by Heather Catchpole) Provides an overview to bushfires.
Issues March 2007, pages 4-7 Fire: Destructive and part of the natural order (by Kevin O’Loughlin) Explores the roles of research, management and education in living with bushfires.
Land for wildlife No. 14, July 2000, pages 1-8 Fire as a wildlife habitat management tool (by Cath Moran and Penny Watson) Looks at the effects of fire on native flora and fauna and its use as a tool to protect habitats.
New Scientist 16 September 2007, page 29 Water bombs could boost arsenal against bushfires Reports on invention which transforms cargo planes with rear ramps into ‘water bombers’.
29 January 2005, pages 7-8 Quake, flood, fire. Will we be ready? (by Emma Young) Discusses initiatives towards the development of disaster warning systems and management plans.
22 January 2005, page 22 Virtual bushfire experience could save lives Looks at the potential use of virtual-reality bushfire simulations to save lives.
17 July 2004, page 14 Trace chemical sows seeds of plant resurrection Study identifies chemical that stimulates new growth in seeds.
27 March 2004, pages 44-46 Fire man (by Rachel Nowak) An interview with Phil Cheney who studies wildfires.
6 October 2003 Controlled bushfires damage – not protect – wildlife (by Emma Young) Reports that controlled bushfires are damaging biodiversity.
Science 13 August 2004 A compound from smoke that promotes seed germination (by Gavin Flematti, Emilio Ghisalberti, Kingsley Dixon and Robert Trengove) Reports on a chemical derived from smoke which has been shown to increase germination.
ScienceNetwork 24 January 2007 Using satellites to fight fires – and floods (by Tony Malkovic) Reports on an innovative system used across Western Australia to fight bushfires and floods.
Scientific American August 2007, pages 32-39 Predicting wildfires (by Patricia Andrews, Mark Finney and Mark Fischetti) Investigates the behaviour and predictions of wildfires.
26 December 2006 Warmer Atlantic, climate change presage more, and worse, western wildfires (by David Biello) Looks at the use of tree-ring records and fire-scar data to predict the scale of wildfires.
7 July 2006 Warming climate may increase western wildfire woes (by David Biello) Links the bigger and more frequent fires in the western United States to climate change.
7 November 2002 Wildfires factor significantly in global carbon balance (by Sarah Graham) Looks at the impact of wildfires on levels of greenhouse gases.
Wingspan Vol. 15, No. 3, September 2005 Contains a number of articles on bushfire management and biodiversity, including:
Useful sitesHow wildfires work (How Stuff Works, USA)
Provides an introduction to wildfires.
Natural hazards – bushfire (Geoscience Australia)
Includes information on what bushfires are, their causes and locations.
How fires affect biodiversity (Centre for Plant Biodiversity Research, Australia)
Presents examples of how fires affected plant and animal species in Australia.
The passage of fire (Australian plants online)
Looks at the effects of the bushfire in the upper Blue Mountains on a range of plant species.
Fire ecology (Parks Victoria Education, Australia)
Provides information on the adaptations of plants to bushfires.
Department of Sustainability and Environment Victoria (Australia)
Savannah Explorer (Australia)
Fire ecology and management in northern Australia (Tropical Savannas CRC and Bushfire CRC)
Fire management: Fire, flora and fauna (Parks and Wildlife Service Tasmania, Australia)
Provides information on the effects of fires on flora and fauna.
Australian Broadcasting Corporation
The Nature Conservancy (USA)
Fire ecology (Ontario Ministry of Natural Resources, Canada)
Provides information on the relationship between fires, the environment and living organisms.
Fire ecology and management (CSIRO Tropical Ecosystems Research Centre, Australia)
Contains information on the research projects conducted at the research centre.
Fire management (Department of Environment and Conservation, Western Australia)
Contains information on fire management principles and their applications.
Living in a land of fire (Department of the Environment and Water Resources, Australia)
Provides a series of integrative commentaries on fire.
Fire note (Bushfire CRC, Australia)
Contains a number of articles which provide background information on issues related to fires.
Understanding bushfire behaviour (CSIRO, Australia)
Provides an outline to research on understanding bushfire behaviour.
Rural Fire Service (Department of Emergency Services, Queensland Government, Australia)
NSW Rural Fire Service (New South Wales Government, Australia)
Glossarylignotuber. A woody swelling on underground or partly underground stems or roots containing buds and food reserves. Plant species which possess lignotubers are mostly fire tolerant. Species that do not possess lignotubers usually survive fires through massive seed regeneration. Ramsar-listed wetland. A wetland listed under the Ramsar Convention – an international treaty aimed to conserve and maintain the sustainability of wetlands.
External sites are not endorsed by the Australian Academy of Science. Posted January 2008. The Australian Foundation for Science is a supporter of Nova. This topic is sponsored by the Australian Research Council Linkage Learned Academies Special Projects Grant.
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