Complex cure the key to curbing desertification

A report says desertification has eased in parts of Northwest China as the climate and vegetation coverage have improved, with experts saying the country has adopted a complex range of methods to treat the problem rather than just planting trees.

The China Blue Book on Climate Change released recently by the China Meteorological Administration said the overall vegetation coverage across the country has been increasing since 2000.

Last year, China's annual average normalized difference vegetation index, used to estimate the density of green coverage, was 7.6 percent higher than the average between 2000 and 2019.

The climate in areas with key ecological resources has continued to improve. From 2005 to 2020, the area of land affected by desertification in the Shiyang River Basin in Northwest China's Gansu province shrank, with the expansion of nearby deserts slowing. The basin is surrounded by the Badain Jaran and Tengger deserts.

In Northwest China, home to most of the country's deserts, precipitation in the central and northern parts of the Qinghai-Tibet Plateau and the northern and western parts of the Xinjiang Uygur autonomous region has increased significantly since 1961.

Lu Qi, a researcher from the Chinese Academy of Forestry's Institute of Desertification Studies, said a wetter climate had mitigated desertification in recent years.

"However, this is not a trend but a period of climate change," he said. "A year or even a decade that experienced more precipitation does not guarantee a sustainable good environment because climate is a long-term story in human history."

Instead, Lu attributed China's environmental improvement to the practice of integrated treatment.

"Tree planting is not the only treatment method," he said. "The country has adopted a complex tool kit. Take Gansu's Shiyang River Basin as an example, the provincial government built water conservancy projects to control deserts expanding into towns along the river."

Another example is Shapotou in Zhongwei, Ningxia Hui autonomous region, on the edge of the Tengger Desert. In 1955, the Chinese Academy of Sciences set up a desert research and experiment station in the area to fix sand and prevent it from covering the railway from Baotou in the Inner Mongolia autonomous region to Lanzhou, Gansu.

Since opening to traffic in 1958, the railway has operated normally along the 140 kilometers of its 990 km overall length that runs through desert.

Researchers from the station devised a combination of greenbelts, sand break fences and straw checkerboards to fix and prevent the movement of sand, the academy said.

To make a checkerboard, workers first spread stalks to form a square on the sand. They then pierce the stalks with a shovel so part of stalks drop into the sand, with the rest above the ground. In this way, sand inside a grid about a meter square is not easily blown away by the wind.

In the Kubuqi Desert in Ordos, Inner Mongolia, traditional Chinese medicine herbs have been planted under photovoltaic panels to prevent the movement of sand and increase local residents' incomes.

In the past five years, the area subject to desertification across China has decreased by an average of 2,424 square kilometers a year, the National Forestry and Grassland Administration said, adding that at the end of the 20th century it was expanding by 10,400 sq km a year.

Lu said that achievement would have been impossible solely through the planting of trees.

"China has inhibited excessive use of natural resources in Northwest China," he said. "Taking into account various environmental conditions, the country plants trees or grass where it is suitable, and leaves areas as deserts as they originally were."

Lu said that treating desertification doesn't mean eradicating all the deserts.

"Areas with desertification may not have been deserts before but experienced soil degradation due to overgrazing, excavation, abuse of water resources, and climate factors," he said. "Controlling desertification is to return places that shouldn't be deserts to their original appearance.

"However, many deserts, born to be native geographical landscapes, are home to rare wild animals. Most people misunderstand deserts as something bad. We should respect the law of nature and realize there is no need to turn all the deserts into green land."

lihongyang@chinadaily.com.cn