Starting in 1978, China began to establish a protective forest belt in the northern part of the country. 8,000 kilometers long and 400 to 700 kilometers wide, the forest belt is designed to prevent soil erosion and damage caused by windborne sand. Over the last 30 years, enough trees have been planted that if they were lined up single file, they would encircle the globe 3,750 times. The program has been hailed as the world's greatest ecological restoration project. The forest belt is known as a Green Great Wall, preventing the southern advance of desertification.

Photo by Hui Huaijie