Amazon Rainforest

The Amazon Rainforest is the largest rainforest in the world. It extends for 3,000 mi (4,828 km) from the ANDES mountains to the ATLANTIC OCEAN. The rainforest covers parts of BRAZIL, PERU, ECUADOR, COLOMBIA, BOLIVIA, and VENEZUELA, encompassing over a billion acres and covering one-third of South America. The 6,500 mi (10,461 km) of the great AMAZON RIVER, second only to the NILE RIVER in length, flows throughout the rainforest. Eleven hundred tributaries, some of which are over 1,000 mi (1,609 km) long, feed into the Amazon River.

Since the rainforest is close to the equator, its CLIMATE is hot and humid at all times. From 40 to 80 in (100 cm to 200 cm) of rain falls annually in the eastern section of the rainforest, while the western region experiences around 160 in (400 cm) of rain each year. THUNDERSTORMS occur more than 200 days of the year. In sections of the rainforest that are closest to the equator, rain falls almost constantly. Trees within the rainforest are always green, but many shed their leaves in response to biological and climatological changes.

The Amazon Rainforest is considered a resource for the entire world, in part because of the plant life that protects the world’s environment from the greenhouse effect. When the rainforest performs its natural function, at last 50 percent of the rain returns to the atmosphere on the leaves of trees through the process of evapotranspiration. This process uses the water loss from the trees in the rainforest to form clouds that make rain in other, more protected parts of the rainforest area.

The rainforest is made up of four layers: the emergent layer, the canopy, the understory, and the forest floor. The emergent layer is located at the top of the trees of the rainforest. This layer is subject to intensive amounts of sunlight, high temperatures, low humidity, and strong winds. The canopy, sometimes called the upper canopy, is made up of the tallest trees in the forest. These trees, which may grow to 200 ft (61 m), pro-tect the land below from harsh sunlight. The middle layer of the rainforest, known as the understory or lower canopy, may be as high as 20 ft (6 m). It is made up of various small trees, vines, and shrubs. The forest floor or the jungle is composed of ground cover such as herbs, mosses, and fungi. The wildlife in this section of the rainforest eats roots, seeds, leaves, fruit, and smaller animals.

Around two-thirds of all animals and plants in the rainforest inhabit the canopy. For instance, in a section of a canopy in the Peruvian rainforest, scientists identified over 50 species of ants, 1,000 species of beetles, some 1,799 arthropod species, and approximately 100,000 species of fauna. Samples taken from canopies in PANAMA, Brazil, Peru, and Bolivia revealed over 1,500 species of beetles in each canopy. Because the canopy area is not easily accessed and because many insects find shelter underneath the leaves, it is thought that thousands of species may yet be discovered. Some species of wildlife spend their entire lives in the trees of the rainforest.

Poverty, population growth, greed, and shortsightedness have historically been the major threats to the Amazon Rainforest. Construction, which often operates on the principle of “slash and burn,” has created a new threat since the middle of the 20th century. For instance, in February 2001, officials in Ecuador contracted with an international consortium to construct the 300-mi (483-km) Oleoducto de Crudos Pesados (Heavy Crude Pipeline) intended to transport crude oil from the rainforest to the Pacific Coast, affecting forests and wildlife and displacing native inhabitants.