Lesson from the natureToday, too many trees are still being cut down in many countries and floods all over the world are getting more and more serious. A lot of land has gone with them. This is lesson from the nature.When people move into a new place, they often cut down trees or pull out many wild plants to make farmland. Maybe they don’t think they can eat trees or grass. They don’t know very much that trees can stop floods and the wind from washing or blowing the earth away, and that many of these wild plants are food for some wild animals. If the animals cannot find enough plants to eat, they will die or have to leave the place.In one part of the United States, for example, the deer there like to eat a kind of wild flower. The mountain tigers there eat the deer. But people killed many mountain tigers to protect the deer. Soon there were so many deer that they ate up all the wild flowers. Then the deer began to eat the green leaves of the young trees. So the farmers thought of ways to protect their trees. Now the deer had nothing to eat and many of them died.The number of trees, deer, tigers, wild flowers and plants has changed much---less and less. We need to do more to keep the balance of the nature.Now moreGreat Green Wallsare needed to save a lot of land and wild animals all over the world. People try to plant many more trees and grass, to protect wild plants and all kinds of wild animals, even tigers. People came to understand: to protect all living things on the earth means protecting people themselves.