Guo Chengwang (L), 90, and his grandson Guo Jianjun pose with the tree that Guo Chengwang planted in 1984 at Maotuan Village in Jingbian County of Yulin City, northwest China's Shaanxi Province, July 31, 2018. The administrative region of Yulin City is located to the south of the Maowusu Desert. Environment protection measures have curbed the expansion of the desert and then witnessed the retreat of the desert as a result of the increase in planted forests and grasslands after reducing and stopping farming and animal husbandry. (Xinhua/Tao Ming)