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African wildfires may become larger and more intense as more people move to cities, a study has found.
Traditional ways of using controlled burning to prevent out-of-control natural fires could die out in many rural areas as urbanisation increases, leaving grassland free to build up, says the paper, which was published this week (23 May) in Philosophical Transactions of the Royal Society B.
This would provide extra fuel for fires sparked by lightning strikes later in the year, says author Sally Archibald, an environmental researcher at the University of Witwatersrand in South Africa.
“If people stopped managing their landscapes by burning small early-season fires, then it is possible that more areas would burn in late-season intense fires,” she says.
The paper studied data on the incidence and causes of fires in the southern hemisphere. It found that there were about the same number of early- and late-season fires, but that fires later on are usually larger in size and intensity and so burn a much bigger area.
“If people stopped managing their landscapes by burning small early-season fires, then it is possible that more areas would burn in late-season intense fires.”
Sally Archibald, University of Witwatersrand
Archibald argues that fire safety regulations should encourage people to continue burning grasslands in the early season, as human-made fires are easier to control and are less likely to damage houses than more intense, late-season fires. But she says that regulations must be flexible enough to also permit the intense, human-made fires needed to control shrubs that are encroaching on farmland and pasture.
“It would be counterproductive to make regulations that are too prescriptive,” she says.
The study says that traditional proactive burning of grassland in Africa benefits wildlife by creating important post-fire habitats and preventing dense thicket building up in grassland areas. Archibald writes that efforts to prevent and suppress all fires, often introduced during the colonial period, clash with valuable traditional fire management methods.
Government support for controlled burning could lower the risk that wildfires pose to homes and farmland by reducing the fuel load, explains Brian van Wilgen, a biologist at Stellenbosch University, also in South Africa.
Other ways of tackling fire risk include clearing areas of vegetation to create firebreaks that stop fire from spreading and not planting fire-sensitive crops near dry grasslands, he says.
Van Wilgen and Archibald agree that promoting indigenous fire management techniques, such as controlled burning and crop selection, would not clash with existing fire regulations.“In essence, there is nothing that distinguishes indigenous practice from modern fire ecological management,” van Wilgen says. “The problems we have arise from modern developments, like planting fire-sensitive crops and plantations into fire-prone ecosystems.”