Amazon Rainforest

The Amazon rainforest, with an area of about 6 million sq km (about 2.3 million sq mi), covers much of equatorial South America and contains more species of flora and fauna than any other ecosystem in the world. Trees constitute about 70 percent of the plant species found in rainforests. Currently, the Amazon rainforest is being cleared at an alarming rate for timber and agricultural purposes.

Will and Deni McIntyre/ALLSTOCK, INC.

Tropical Rainforest

The Amazon, seen here, is the second longest river in the world, and has the greatest number of tributaries. Its high rainfall and year-round heat and sunshine ensure a profusion of all forms of life, stratified into as many as five distinct layers, from the ground to the canopy of the tallest trees.

Will and Deni McIntyre/ALLSTOCK, INC.

Interior of Rainforest, Costa Rica

equatorial forests of Amazonia or monsoon forests such as this one in Costa Rica, tropical rainforests often provide the only home for thousands of species of animals and plants, both known and as yet undiscovered. Logging and agriculture are threatening the survival of tropical rainforests throughout the world, and are causing the extinction of many of the species that inhabit them.

Michael Fogden/Animals Animals

Deciduous Monsoon Forest

The deciduous monsoon forest is characteristic of the northern Indian Ocean along the coasts of India, Burma, and Southeast Asia. Typical throughout much of the year in such forests is heavy daily rainfall with intermittent dry periods during which the deciduous trees shed their leaves.

Paolo Koch/Photo Researchers, Inc.

Vertical Stratification of a Rainforest

This illustration shows the characteristic vertical stratification, or layering, of plants and trees in rainforests. Generally, there are at least three discernible strata (layers) of plant growth in rainforests. At the upper canopy level, the tops of trees reach heights of 30 to 50 m (100 to 160 ft), while outstanding emergents may tower to 60 m (200 ft); this layer is uneven, with breaks between treetops, allowing sunlight to filter through to the middle layer. This middle layer, the densest layer of the rainforest, includes another level of treetops, lianas (woody vines), and epiphytes (plants that thrive on airborne nutrients). The growth at the middle layer is so dense that little sunlight reaches the forest floor; only 1 per cent of the light above the upper canopy gets through to the floor. Thus the lowest layer is also the thinnest, sparsely populated with tiny seedlings and shoots. Each layer of flora houses its own faunal communities; many animals live in ecological niches at one layer and never venture beyond to other layers of the forest.

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Corpse Lily, Kinabalu National Park  

The Rafflesia arnoldii, or corpse lily, is the largest flower in the world, weighing up to 7 kg (15 lb) and measuring up to 91 cm (36 in) wide. Found in Malaysia and Indonesia, the flowers emit the stench of rotting meat to attract certain flies.

Bios/Peter Arnold, Inc.

Greater Dwarf Lemur

The greater dwarf lemur is one of four species of dwarf lemur which are found only in the forests of the island of Madagascar. Being nocturnal, its eyes are large and light-sensitive. Dwarf lemurs hibernate during the dry season, when food is scarce, and live off of fat stored in their long tails.

Howard Uible/Photo Researchers, Inc.

Broad-Billed Motmot

The tail of the broad-billed motmot, like that of all motmots, is trimmed near the end, giving the tail the appearance of a tennis racket. The birds, found in the tropical forests of Central and South America, trim these feathers to maintain the shape and swing them from side to side in a rhythmic fashion, appearing like a metronome. The reason for this behaviour remains a mystery to zoologists.

Kevin Schafer/Peter Arnold, Inc.

Destruction of Amazonian Rainforest

This area of the Amazon rainforest has been cleared by burning, following which a ground cover of small plants grew quickly, but could not prevent the rapid erosion of the soil by rain water, the signs of which can be seen in the channels leading down to the central gully. The fast erosion of already nutrient-poor soil makes regeneration of the forest an even more precarious prospect.

Anne LaBastille/Bruce Coleman, Inc.

Slash and Burn Deforestation

The deforestation technique of slash and burn, utilized extensively to clear large areas of forest for agricultural and other purposes, causes an enormous amount of environmental damage. The large amounts of carbon dioxide given off into the atmosphere during burning adds to the greenhouse effect. The removal of all trees and groundcover destroys animal habitats and greatly accelerates erosion, adding to the sediment loads of rivers and making seasonal flooding much more severe.

Sean Morris/Oxford Scientific Films

Web Links

The Tropical Ecology Web Site

The Tropical Rainforest in Suriname