The Yangtze river has been prone to flooding in recent years

Lei Jiafu, deputy chief of the state forestry administration, who announced the plan, said that despite several smaller-scale attempts, China had so far been unable to reverse the trend of environmental degradation.

Large areas of natural woodland were cleared throughout the last century to create farmland and provide timber for industry.

The rampant deforestation has caused ecological disturbances to wide areas of the countryside - and is being blamed for the life-threatening summer floods on the Yangtze River and the severe spring sandstorms which are a health hazard to millions.

Olympic effort

Over the next 10 years, the Chinese Government hopes to reforest rather than deforest with its massive tree-planting programme.

On Tuesday, Mr Lei gave the most detailed account yet of what he called "unprecedented" plans to stem forest reduction.

China is bracing itself for a huge environmental clean-up ahead of the 2008 Olympics, but the new proposal also aims to combat the blinding sandstorms, flooding, illegal logging, and rapid desertification besetting the country.

Protected habitats are to be set aside for pandas

Beijing has planted millions of trees since the 1980s in an attempt to stem erosion and dust storms, but there has been little noticeable improvement.

The plans unveiled on Tuesday include six separate projects that range from reforesting hillsides to creating protected reserves for pandas, Tibetan antelopes and rare orchids.

In addition, a seeding programme to convert cropland to woods was projected to raise forest and grass cover by 5%, said Mr Lei.

He estimated that the resulting green belts could reduce wind speeds by 30% to 50% and cut sand and dust levels dramatically.

"If we increase the forest cover, then we can relieve to a certain extent the occurrence of sandstorms," he said.

Concern for the poor

But there is widespread scepticism about China's clean-up campaign.

The situation is particularly polarised in the countryside, where two-thirds of China's 1.3 billion people suffer low incomes and high taxes, and often have no choice but to deforest the land.

Part of the new plan involves subsidising farmers to turn cropland back into forests.

But there is concern that millions of struggling farmers will be forced to sacrifice their cropland and receive little in return.

Mr Lei said that China was under enormous pressure because of high population and economic growth.

But the country's ecological damage has often been driven as much by official policy as by economic and demographic pressures.

Hills were stripped of trees in the 1950s to fuel the steel industry and clear farmland.

And in the 1990s, efforts to expand grain output led to the clearing of more hillsides to make way for farmland in areas with fragile soil that quickly turned to desert.