Forest rangers eat dinner together in Laixi City, east China's Shandong Province, Jan. 7, 2019. The team of forest rangers, whose average age is above 40, have worked at Daqing Mountain provincial forest park for many years. There haven't been any wild fire accidents in Daqing Mountain for 15 years under their protection. (Photo: Xinhua)

Jiang Jinxiao, team leader of the forest rangers, introduces the key monitoring areas for the fire prevention in the Daqing Mountain in Laixi City, east China's Shandong Province on Jan. 7, 2019. The team of forest rangers, whose average age is above 40, have worked at Daqing Mountain provincial forest park for many years. There haven't been any wild fire accidents in Daqing Mountain for 15 years under their protection. (Photo: Xinhua)

Forest rangers work at the watch tower in the Daqing Mountain in Laixi City, east China's Shandong Province on Jan. 7, 2019. The team of forest rangers, whose average age is above 40, have worked at Daqing Mountain provincial forest park for many years. There haven't been any wild fire accidents in Daqing Mountain for 15 years under their protection. (Photo: Xinhua)

Forest rangers patrol in the Daqing Mountain in Laixi City, east China's Shandong Province on Jan. 7, 2019. The team of forest rangers, whose average age is above 40, have worked at Daqing Mountain provincial forest park for many years. There haven't been any wild fire accidents in Daqing Mountain for 15 years under their protection. (Photo: Xinhua)