tropical rain forest

Definition

Dense forest of evergreen trees growing in regions of heavy year-round rainfall in tropical latitudes (such as Amazon Basin, Borneo, New Guinea, North-East India, and Zair Basin) and warm temperate latitudes (such as Eastern Australia, Florida, South Africa, South Brazil, South and Central China, South Japan, and New Zealand's North Island). Nearly half of these forests are in the Central and South America, mainly the lower Amazonia and along the coasts of Columbia and Ecuador. Tropical rain forests are the most complex and diverse ecosystems, and sustain the greatest concentration of biological diversity (half of all species of animals and plants) on the Earth. Malaysian rain forests, for example, alone contain some 2500 species of large trees, and Amazon rain forests about 20 percent of all bird species. Once they covered 14 percent of the land area which by 1991 had been reduced to just about 7 percent, and continues to be reduced by about 100,000 square kilometers (62,000 square miles) every year. In addition to producing a vast range of natural products, tropical rain forests help regulate the planet's weather patterns and provide most of the oxygen required to sustain life. They are one of the most threatened ecosystems on the earth, and their disappearance is intimately linked to global warming.