Just a few thousand years ago rain forests covered 14 percent of the Earth's land surface, or 5 billion acres. Humans already have destroyed half of this forest area, with most damage occurring in the last 200 years. Although tropical rain forests now cover just 2 percent of the globe, they are home to more than half the world's living plant and animal species. It is not only quantity of life, but diversity as well, that makes rain forests so vital. Some of the strangest and most beautiful plants and animals are found in rain forests, and undoubtedly there are just as many we do not even know about.
Rain forests are the predominant natural vegetation throughout the wet tropics.
The defining characteristics of tropical a rain forest are temperature and rainfall. Wherever temperature is high enough and rainfall heavy and regular enough, there is rain forest. Rain forests are being eliminated for timber, minerals, agriculture, and human settlement. Other motives, such as the desire to conquer nature or to control unoccupied territory, also are factors in deforestation. Overpopulation and peasant agriculture is often cited as the cause of deforestation.