Rainforest

A rainforest is a forested biome with high annual rainfall due to the Intertropical convergence zone. Some cite a minimum normal annual rainfall of 2000 mm (about 100 inches or 200 centimetres), with normal rainfall at least 60 mm during each of the twelve months of the year. Others set the minimum annual rainfall barrier as low as 1700 mm (about 67 inches). The soil can be poor because high rainfall tends to leach out soluble nutrients. This type of biome is found in both temperate and tropical climates. As well as prodigious rainfall, many rainforests are characterised by a high number of resident species and tremendous biodiversity.

Oxygen producer

It is sometimes estimated that rainforests provide up to 40% of the oxygen currently found in the atmosphere (this figure is strongly disputed by some lobbyists, groups and scientists, e.g. http://www.cfact.org/site/view_article.asp?idCategory=5&idarticle=274, who say that it is only young, fast-growing trees that produce oxygen, and even that the rainforests may be a net consumer of oxygen). And yet, tropical and temperate rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century, so that the area covered by rainforest around the world is rapidly shrinking. Another form of destruction in the rain forests is the burning of trees. It is estimated that the rainforest was reduced by about 58,000 km² annually in the 1990s. Rainforests used to cover 14% of the Earth's surface. This percentage is now down to 6% and it is estimated that the remaining natural rainforests could disappear within 40 years (mid-21st century). Biologists have estimated that large numbers of species are being driven to extinction, possibly more than 50,000 a year, due to the removal of habitat with destruction of the rain forests. Many charities and conservation organizations use donation money to protect the rainforest trees from logging.

Related Topics:
Atmosphere - Lobbyists - Tropical - Temperate rain forest - Logging - 20th century - Extinction

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