在很久以前,全世界的陆地几乎全被苍郁茂密的森林所覆盖。然而大约在200万年前,当地球表面温度下降,冰期到来的时候,森林面积迅速减少;随着人类社会的发展,人们开始从事农牧业生产,毁林开荒,刀耕火种,碎林放牧,特别是历代统治阶级为了自已的穷奢极欲,破坏了很多森林;资本主义产生以后,工业的发展,掠夺式的采伐,以及战争和森林火灾等原因,森林更加遭到严重的破坏,致使森林面积逐渐减少。昔日认为取之不尽,用之 Long ago, almost all the land of the world was covered by the lush forests. However, about 2 million years ago, when the earth’s surface temperature dropped and the ice age came, the area of ​​forest decreased rapidly. With the development of human society, people began to engage in farming and animal husbandry, deforestation and wasteland, slash-and-burn farming, Since the ruling class of the successive generations sacrificed its luxury and desires for its own sake, it has destroyed many forests. After the emergence of capitalism, industrial development, predatory logging, and war and forest fires, the forests were even more seriously damaged, causing forest area gradually decreases. In the past that the inexhaustible, use it