A project to cover the outskirts of Beijing with greenery to reduce pollution is about to end, despite delays caused by snowfall in November.

More than 40,000 trees will have been planted over 66.7 hectares in northwestern Yanqing county by the end of this month, concluding the capital's 250-sq-km afforestation project.

Two villagers plant trees on snow-covered soil in Yanqing county, Beijing, on Friday. A greenery project was held up as the county was hit by the biggest snowfall in 52 years. [Photo by Zheng Xin / China Daily]

"It was the largest snowfall in 52 years and the afforestation project was severely held up," said Wang Shuqin, deputy director of the county's landscape and forestry bureau.

"It is believed that, by the end of 2012, a total of 1,533 hectares of barren land will have been transformed with green plants."

She said the snow not only caused power cuts and killed livestock at chicken and pig farms, but also halted the tree-planting project.

"It was impossible to plant trees in the soil, which was frozen hard, with snow piled high," she said. "The work was an unprecedented challenge, as it was the heaviest snowfall since 1960."

Zhang Shunjiang, a Yanqing resident working on the greening project, said although the snow has now gone, progress is still slow due to low temperatures.

"It's not as easy to dig a hole for a young tree when the soil is frozen," he said. "Workers here could dig some 40 holes a day in spring, but I can only finish 15 because of the temperatures and soil condition."

The snow did not pose a threat to the majority of trees already planted, with the bureau saying the survival rate was about 95 percent.

But it damaged more than 4 million trees, including some 160 ancient ones, according to the forestry bureau.

Of the damaged trees, which were mainly found in residential communities, parks and on major roads, more than 3 million had fallen, Wang said.

She said a team of 280 workers and four trucks were sent out and all damaged trees had been saved as of Nov 23.

Wang said the afforestation project on the northwestern outskirts is of great importance, as northwestern winds blowing into the capital in winter usually bring sand and dust to downtown areas.

"Pagoda trees and grass act as a protective shield for the city from dust and sand. They will greatly reduce the pollution from neighboring cities that threatens the capital's air quality," she said.

According to the Beijing Municipal Environmental Protection Bureau, 24.5 percent of PM2.5 - particulate matter smaller than 2.5 micrometers in diameter - comes from neighboring provinces.

The bureau also said plants that have just gone into the ground are expected to prevent as much as 2.1 metric tons of dust from entering Beijing.

Wang Qiuxia, a researcher at Green Beagle, an environmental non-governmental organization, said greenery will also reduce the chances of people developing heart and breathing conditions and even lung cancer.

zhengxin@chinadaily.com.cn