The Yellow River s winding tale of ecological protection, development--China Economic Net en.ce.cn - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from en.ce.cn Daily Mail and Mail on Sunday newspapers.
How long does it take for a little sapling to grow into a big tree, and how many trees are needed to make a forest? Zhang Zhisong, 70, has spent the past six years finding out the answers.