More than three hundred years ago, about half of the USA's land was covered by forest. But now the forests are almost 1 They can't stop good land from being sold. Today too many trees are being cut 2 in the USA. China doesn't want to follow the USA's 3 So China has built a new Great Wall of trees. It will stop the 4 from blowing earth away and stop the sand from moving towards the rich farmland. It has 5 saved a lot of land. We must plant 6 trees every year. The more, the better.