People plant trees at the Saihanba forest in Weichang Man and Mongolian Autonomous County of Chengde City, north China's Hebei Province, May 13, 2014. Saihanba is a vast forest covering nearly 75,000 hectares. It was a piece of barren land 55 years ago, but decades of hard afforestation efforts turned it into an important ecological shield for Beijing and Tianjin. (Xinhua/Wang Xiao)