Tropical rain forests are found in an equatorial belt around the earth in areas where high temperatures and rainfall are, more or less, constant throughout the year. The largest formation of tropical forests is centered on the Amazon basin in South America while the smallest is found in central and western Africa, centered around the Democratic Republic of the Congo, formerly known as Zaire. The forests of Southeast Asia are intermediate in size but not in biodiversity. It is within these forests that the Asian apes: orangutans which are great apes and the small apes, gibbons and siamangs, reside.
Although the plant and tree species in the three great tropical rain forest formations are very different, nonetheless, there are similarities in terms of forest structure, physiognomy, appearance, species richness, and forest succession.
Tropical rain forests differ from most temperate forests in a number of ways. One of the most obvious is the relative paucity of tree species in temperate forests compared to the amazing diversity of plant and animal species in tropical rain forests. While tropical rain forests may have hundreds of different tree species, a temperate forest may only have ten or so native species. Seven hundred and eighty species of trees were reported from a single 25 acre (10.1 hectares) plot of forest in Borneo, a measure of the wide diversity found in tropical rainforests.
Covering only about 7% of the earth’s surface, tropical rain forests are home to at least half the world’s known terrestrial species, including 75% of all insects.
Another basic difference between tropical and temperate forests may not be obvious to the casual observer. Ninety percent of the organic matter found on the tropical rain forest floor is recycled every six months, a process that in temperate forests may take three years. In Tanjung Puting a tree may totally disappear within a few years after dropping to the forest floor. This energized recycling of nutrients is so complete that no deep layer of humus builds up and the soil tends to be barren, with a relative paucity of leaf litter. More than 60% of the wet tropics have infertile soils. Thus, if trees or other vegetation are cut down or burned, the ground eventually turns to sand.
Today, however, tropical rain forests are being rapidly annihilated all over the globe with dreadful consequences for wildlife and biodiversity. While cattle ranching and soy bean plantations have caused much harm in the Amazon, the forests of Indonesia and Malaysia are being destroyed by rampant conversion to palm oil plantations and timber estates. The mechanism of this destruction, frequently used by those who destroy the forest, is fire. The droughts associated with the appearance of the weather phenomenon known as El Nino are occurring with increasing frequency, thus making it easier to burn forests. As a consequence, Indonesia has become the world’s third largest emitter of carbon into the global atmosphere!