Environmentalists want an investigation [pic courtesy of Wilderness Society]

Standing at 79 metres (260 feet) the massive hardwood - known as El Grande - stood unharmed by man for almost four centuries. Although there are taller trees on Tasmania, El Grande is thought to be the largest tree in Australia in terms of volume.

Forestry Tasmania has said it is too early to be sure that the tree has been irreparably damaged, although it admitted that the tree's base and much of its interior had been severely charred.

A senior forestry manager told The Age newspaper in Melbourne that the tree might yet still be alive.

"It's certainly been charred, but we expect it to grow new shoots."

He said reports that the tree had died were "an overstatement".

However independent botanist Alan Gray said the tree was already dead, with dead tissue reaching up to 65 metres (213 feet) from its base.

Investigation demanded

Forestry officials in Tasmania said the fire, in Florentine Valley, was a routine burn-off conducted to clear debris from the forest undergrowth following a wood-chipping operation.

If the authorities couldn't look after one tree, how could they be trusted to take care of the state's forests? Campaigner Mike Noble

However it burned out of control. Environmentalists in Tasmania, where the Greens party attracts 20% of the vote, have accused the authorities of being unfit to protect one of the world's most diverse rainforests.

They have demanded an investigation.

The state's Wilderness Society said there were vandals in the highest levels of government.

Campaigner Mike Noble said: "If the authorities couldn't look after one tree, how could they be trusted to take care of the state's forests?"

Ancient landmarks

The fate of El Grande has intensified scrutiny of the burning of Tasmania's forests to provide wood chip for export. Fires are started to clear the undergrowth.

Forestry officials have insisted they are committed to safeguarding Tasmania's environment.

They point to the state's giant tree protection policy which provides guidelines for national parks and other reserves.