Photo taken on Oct. 3, 2012 shows a visitor takes pictures of populus euphratica forest in Ejina Banner, north China's Inner Mongolia Autonomous Region. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Zhao Junchao)

Photo taken on Dec. 26, 2010 shows the scenery of snow-covered trees in the Lushan Mountain in Jiujiang, east China's Jiangxi Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua)

Photo taken on Sept. 30, 2010 shows the scenery of cloud-shrouded trees in the Lushan Mountain in Jiujiang, east China's Jiangxi Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua)

Photo taken on May 2, 2008 shows the scenery of the National Forest Park in Zhang Jiajie, central China's Hunan Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Yang Hua)

Photo taken on Feb. 20, 2013 shows the scenery of Lushan Mountain in Jiujiang, east China's Jiangxi Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Fu Jianbin)

Photo taken on July 19, 2009 shows the scenery of Sixi scenic spot in Zigui County of central China's Hubei Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Zheng Jiayu)

Photo taken on Feb. 20, 2013 shows the scenery of Lushan Mountain in Jiujiang, east China's Jiangxi Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua)

Photo taken on Oct. 18, 2012 shows the scenery of forest-covered mountains near Shuanglong Lake in Xuanen County of central China's Hubei Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Song Wen)

Photo taken on Oct. 27, 2012 shows the scenery of trees in Jiuzihe Town of Luotian County in central China's Hubei Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Chen Li)

Photo taken on May 19, 2012 shows the scenery of a forest park in Sanya, south China's Hainan Province. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Liang Fuying)

Photo taken on Sept. 18, 2011 shows the scenery of Greater Khingan range in north China's Inner Mongolia Autonomous Region. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Yu Changjun)

Photo taken on Feb. 18, 2013 shows the scenery of cloud-shrouded trees in the Longlin Autonomous County of All Nationalities, southwest China's Guangxi Zhuang Autonomous Region. China's Arbor Day, or Planting Trees Day, which falls on March 12 each year, is an annual compaign to encourage citizens to plant and care for trees. (Xinhua/Wei Wanzhong)