On Beishan Mountain outside Beijing, trees have been planted on what was once barren rock.

More than 10,000 men removed thousands of hectares of rocks with explosives before hauling up soil and trees.

"Trucks could not go up the mountain, so we had to carry the soil ourselves," Bai Yuanwang, a 36-year-old worker from Hebei province, said.

The 1,000-m Beishan Mountain was forested to shield Beijing from dust storms. The mountain is located 74 km from the capital in Yanqing county.

"It's a 2,400-hectare project that took six years to complete," Li Fengyi, forestry director of the county said.

"I can't say how much this project will help stop sandstorms hitting Beijing, but it has changed the landscape and environment in my county completely."

Sandstorms have always been a problem for Beijing officials. When they strike, everything seems to turn brown.

Since 2000, Beijing has speeded up the building of protection belts. It built 50 to 100-m wide forest belts along five of its newly built expressways this year, and plans to build another three next year.

Millions of trees are also being planted elsewhere in Beijing to combat desertification and soil erosion.

The huge Olympic Green Forest Park, a key environmental project of the Olympics that cost 7.7 billion yuan ($1.12 billion) to build, is a typical example of restoration. Today, magpies can be seen in the area among flower-dotted, grassy riverbanks. At the highest point of the park the Olympic venues - the steel-weaved Bird's Nest and the bubble-wrapped Water Cube - can be seen clearly even on a cloudy day.

"We want this park to be Beijing's backyard, which helps keep our ecology in good balance," Tang Tong, deputy director of the park, said. He expects 25,000 visitors a day during the Olympics and 46,000 after the Games.

Neighboring regions are also trying to reduce the impact of dust storms. "Inner Mongolia and Hebei are planting bushes and areas close to Beijing are planting trees," Liu Tuo, director-general of the Sate desertification combating office, said.

"Dust storms will not create any threat to the Beijing Games," Liu said.

"First, they mainly appear in spring between March and May; second, sand storms are appearing less frequently because of our efforts."

China was the world's first country to have a desertification control law. It also has the largest green cover on earth - 53.26 million hectares, but this does not make the task of forestation easy because of the country massive size and complex geology.

"Because of the conditions, the rest of China's forestation is going to be more difficult," Wei Diansheng, director-general of the tree-planting and afforestation department with the State Forestry Administration, said.