Living on the edge in Australia's tinderbox

Choking, frightened communities in the suburbs of Sydney and in the Blue Mountains to the west were bracing themselves yesterday for what forecasters say could be the worst few days of the bushfire outbreak which has already destroyed more than 500,000 hectares (1.25m acres) of vegetation and 170 homes.

With high temperatures, more fierce westerly winds forecast for tomorrow, and no rain in sight, the 1,250-mile front of fires is expected to widen and become almost impossible to douse.

Pessimistic fire chiefs predicted that the emergency, which began on Christmas Day, might last well into next week. The smoke clouds have choked Sydney and deposited ash as far away as new Zealand, 1,400 miles east across the Tasman Sea.

The biggest fire has so far burned 65,000 hectares of bone-dry forest and farmland near Singleton, 80 miles northwest of Sydney. Another has isolated the coastal town of Bendalong, about 120 miles south of the city, where hundreds of people were camped out on the beach yesterday after the only road to the town was cut off by flames and thick smoke.

Meanwhile a 37-mile front was advancing rapidly through the heavily forested Blue Mountains, about 50 miles west of Sydney. Dozens of residents were leaving the tiny town of Bowen Mountain and people living in the Hawkesbury district of Sydney's northern outskirts were being asked to leave too.

The police said about half the 100 blazes had been started deliberately and 26 people had been arrested. The New South Wales premier, Bob Carr, has promised harsh treatment for young offenders.

The fires claimed their first serious casualty yesterday when a firefighter had to be flown to hospital with burns to his feet, legs and hands. Fourteen others trapped by a wall of flame in the Blue Mountains had to be evacuated by helicopter.

Threatened

There was a growing fear last night for the region's wildlife. Thousands of koalas, kangaroos and other animals are reported lost, and 80% of the royal national park which was devastated by fires in 1994 has been affected.

Australians are learning the hard ecological fact that what is happening is not only a natural and regular phenomenon but is almost impossible to prevent in extreme conditions.

The fires may be monumental in scale, but they are by no means the worst Australians have known. In 1983, on a day now known as Ash Wednesday, more than 70 people were killed and 2,000 homes destroyed by wildfires. In 1994 the coastal heathlands of the royal national park were virtually wiped out in similar weather conditions.

New South Wales, Australia's most populous state, is in the most fire-prone corner of the most fire-prone continent in the world. Its tinderbox environment has been shaped by and now depends on regular fires, whether started by lightning or man.

Ecologists say that the controlled burning of eucalyptus forests in the state is carried out on about 5% of the land each year. In semi-arid areas, the land is burned probably every 20 to 100 years. Grassland burns at intervals of one to 20 years, and forests every five to 80 years, with varying intensity.

The silver lining is the certainty that the land will recover and be rejuvenated. Many seeds lie dormant for years until they germinate with the heat of the fires. Seeds of the oaks, hakeas and banksias which burned days ago will now have dropped, and the trunks and underground stems of other plants scorched by the flames will soon shoot. In a few months time much of what now looks like devastated bush will be green, and by next year the land will have mostly recovered. It is all part of the ecological cycle.

The argument now raging is how Australia can best live with fire. As the suburbs expand further into unmanaged bush, accidental or deliberate fires will happen more frequently and continue to threaten more communities.

Extreme weather, which can set off big fires, is also becoming more common. Phenomena like El Nino and long unseasonal droughts induced by global warming are turning relatively moist forests around the world into drier habitats that burn more easily. The fear is that man is creating a vicious circle of destruction in which an increasing number of fires help to change the weather and changing weather produces more fires.

In the past 10 years there have been more big fires than ever. In 1997, the international conservation body WWF says, at least 5m hectares of forests and bush burned in Indonesia and Brazil, together with vast areas of Papua New Guinea, Colombia, Peru, Tanzania, Kenya, Rwanda and Congo. Big fires are a regular occurrence now in Mediterranean countries, Russia and China.

Many were deliberately started, not by young vandals as in Australia but by corporations wanting to clear forest to plant cash crops or to release land for development. Once a forest has burned, speculators find it easier to get planning permission for new homes.

Global problem

But the relationship between deliberate fires and natural forest ecosystems is becoming more and more dangerously unbalanced, the WWF says. Many forests are now burning more frequently than ever before, while elsewhere management programmes are preventing land from burning naturally, leading to ecological problems and more intense fires in the future.

A battle is now on in Australia between environmentalists, who argue that the bush should be left unmanaged to encourage wildlife and preserve the natural landscape, and homeowners, who want more management of the bush and the lighting of controlled preventive fires.

Ecologists have been attacked by some fire experts this week for discouraging, for conservation reasons, the traditional controlled burning of the brushwood and undergrowth which critics say provides the fuel for the fires. They replied that in such extreme weather conditions it made little or no difference whether there was undergrowth.

A big debate on controlled burning policies is now in the offing.

The burning truth

The best way to put out a big fire is as it crests a ridge. Fires go fast uphill and slow downhill. On the forward side a wind blows towards the flames. Firefighters try to set small fires on the far side of a ridge and starve the main fire of fuel. When it falters they try to control it with hoses

Regular bushfires have been part of the natural bush cycle for thousands of years. Each winter large areas are deliberately burned to rejuvenate the land. Only 20% of the fires in Australia are started by lightning.

Fuel builds up in the bush over the years. Gum trees shed their bark, branches and leaves, smaller shrubs die and the bottom three metres of bush is a mass of dead and drying twigs.

Much of the land regenerates quickly. Heathland can be ready to burn again six months after a big fire. In other areas a big fire may not start for 10-20 years

High winds create dangerous fires, sending them through treetops at 30mph or more, leaping ahead of themselves and destroying all in their path. These 'crowning' fires, practically uncontrollable until the weather changes, can cross 400 metres of open water and jump wide firebreaks