How a century of destruction has laid bare the world's rainforests

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The Independent Online

It is estimated that an area of rainforest the size of Poland - some 78 million acres of land - is destroyed each year by logging, mining, farming, fire and other human activities.

It is estimated that an area of rainforest the size of Poland - some 78 million acres of land - is destroyed each year by logging, mining, farming, fire and other human activities.

Rainforests cover about 2 per cent of the earth's surface yet they harbour the greatest concentration of wildlife on earth, which led Norman Myers, the Oxford environmentalist, to describe them as "the finest celebration of nature ever known on the planet".

Between 40 and 50 per cent of all known and yet-to-be-discovered species are thought to live in the relatively small space stretching from the forest undergrowth to the tree canopy.

The richest rainforests occur in tropical climates - as opposed to the cooler rainforests of more temperate regions -- which stretch along the equator from South America and Africa to east Asia. The Amazon is home to the biggest tropical rainforest on earth but has been subjected to one of the most sustained deforestation programmes in recent history.

Last May, a team of American and Brazilian scientists found that the rate of deforestation in the Amazon has accelerated significantly since 1990 despite claims by the government in Brasilia that it is trying to curb both legal and illegal logging.

William Laurance, an expert on rainforest destruction at the Smithsonian Tropical Research Institute in Panama, said forest loss has shot up by 50 per cent in the southern and eastern regions of the Amazon since 2002.

"The recent deforestation numbers are just plain scary. During the past two years nearly 12 million acres of rainforest have been destroyed - that's equivalent to about 11 football fields a minute," he said.

Scientists link the increase in deforestation to Brazil's $40bn (£22bn) development drive, launched in 2000 to build new roads, power lines, gas pipelines, hydroelectric power stations and river-drainage schemes.

Brazilian politicians argued that the development wasneeded to lift millions of people with no access to basic sanitation or education out of poverty. However, some scientists believe land speculation and the rapid expansion of soybean farming and cattle ranching has led to a deforestation rush.

Philip Fearnside, of Brazil's National Institute for Amazonian Research, explained: "Soybean farms cause some forest clearing directly, but they have a much greater impact by consuming cleared land, savannah and transitional forests, thereby pushing ranchers and slash-and-burn farmers even deeper into the forest frontier.

"Soybean farming also provides a key economic and political impetus for new highways and infrastructure projects, which accelerate deforestation by other actors," he said.

History has shown that whenever a road is built through pristine rainforest, deforestation of the surrounding area quickly follows with miners and illegal loggers finding it easier to move in with heavy equipment.

Illegal logging for tropical hardwood is particularly difficult to police given the remoteness of the locations and the ease with which it can be done with chainsaws and trucks.

Mark Cochrane of Michigan State University said that these initial forays into a pristine forest often go unnoticed by satellite observations: "When you view these forests from a distance, they look OK, but when you stand in them, you can see they've been thinned, and that they've changed," he said.

"You can see how they've been chewed up. It's like they have holes punched in them. These holes can make a rainforest dry out and be vulnerable to fire," he added.

Fire is perhaps the most destructive force in rainforest ecology. Both deliberate and unintentional fires are devouring millions of acres each year.

"These rainforest fires are much more frequent than these ecosystems can resist. These fires are flying under the radar and people don't realise what's happening," Dr Cochrane said.

Furthermore, a study by the University of Sao Paulo and the Smithsonian Institution has found evidence that rising carbon dioxide levels in the atmosphere - caused by global industrial pollution - cause some trees to grow faster at the expense of others, potentially destabilizing the ecosystem.

"In general, large, fast-growing trees are winning at the expense of smaller trees that live in the forest understorey," said Alexandre Oliveira at Sao Paulo.

RAINFORESTS IN FIGURES

¿ Brazil's rainforest is the world's biggest, covering two million square miles of the Amazon river basin

¿ Brazil is top of the list for deforestation with more than 2.5 million hectares (6.2 million acres) being lost each year

¿ Indonesia is second, losing more than a million hectares of rainforest, followed by the Congo, Bolivia, Mexico, Venezuela, Malaysia, Burma, Sudan and Thailand

¿ Computer models suggest there will be no rainforests left in 50 years

¿ Sixty per cent of the anti-cancer drugs developed over the past 10 years come from tropical forests.

¿ An area the size of Mexico and Indonesia combined lost its rainforest over the past 15 years

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