Environment Lesson 6: Rain Forest

The country Brazil that houses around 30 percent of the remaining tropical rain forest on Earth, more than about 50,000 square miles of rain forest were lost to deforestation between 2000 and 2005. Biologists are really worried about the long-term consequences. One of them may be drought. Due to deforestation and Global Warming, some rain forests, like the Amazon, began experiencing drought in the 1990s.

Several efforts are underway to discourage deforestation, mainly through sustainable-logging initiatives, on a very limited basis but have had a negligible impact so far.

The plants liberate water into the atmosphere through a process called transpiration. In the tropic regions, each canopy tree generally releases about 760 liters of water every year. The moisture there helps create the thick cloud cover that hangs over most rain forests. So, even when it is not raining, these clouds still keep the rain forest humid and warm.

The plants grow very close together in the rain forest and they have to contend with the constant threat of insect predators. They have adapted them by making chemicals that researchers have found useful as medicines. Bioprospecting, or going into the rain forest in search of the plants that can be used in foods, cosmetics, and various medicines, has really become big business during the past decade, and its bizarre that the amount that native communities are compensated for this varies from almost nothing to a share in later profits.

The National Cancer Institute (NCI) has estimated that close to 70 percent of the anti-cancer plants identified so far are rain forest plants. Calanolide A, A new drug under development by a private pharmaceutical company, possibly for treating HIV, is derived from a tree discovered on Borneo, as per NCI.

A huge lot of trees and plants, have been removed from the rain forest and are cultivated. Nut tree of Brazil is one valuable tree that refuses to grow anywhere but in undisturbed sections of the Amazon rain forest. It is pollinated there by bees that also visit orchids, and its seeds are spread by the agouti, a small tree mammal.

Source: National Geographic