Deforestation occurs at a rate of 150,000 square km per year worldwide (every 2.5 years, an area equivalent to the state of California disappears).  Tropical forests once occupied 16 million square kilometers of the earth's surface, but now cover only 9 million. It is estimated that Latin America and Asia have already lost 40% of their original forest; Africa a little more than half.    In many countries the rate of deforestation is accelerating. For example, most of the forested areas of Bangladesh, India, the Philippines, Sri Lanka and parts of Brazil's rain forest could be gone by the end of the century. Only in the Congo Basin and some of the more isolated areas of the Amazon Basin does the forest remain largely intact.