The Amazon Rainforest (Brazilian Portuguese: Floresta Amazônica or Amazônia; Spanish: \ or Amazonía) is a moist broadleaf forest in the Amazon Basin of South America. The area, also known as Amazonia or the Amazon Basin, encompasses seven million square kilometers (1.2 billion acres), though the forest itself occupies some 5.5 million square kilometers, located within nine nations: Brazil (with 60 percent of the rainforest), Colombia, Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname, and French Guiana. States or departments in four nations bear the name Amazonas after it. The Amazon represents over half of the planet's remaining rainforests and comprises the largest and most species-rich tract of tropical rainforest in the world.------------The name Amazon is said to arise from a war which Francisco de Orellana had with a tribe of Tapuyas where the women of the tribe fought alongside the men, as was the custom among the entire tribe. (Orellana's descriptions may have been accurate, but a few historians speculate that Orellana could have been mistaking indigenous men wearing "grass skirts" for women.) Orellana derived the name Amazonas from the ancient Amazons of Asia and Africa described by Herodotus and Diodorus in Greek legends. Another etymology for the word suggests that it came originally from a native word amazona (Spanish spelling) or amassona (Portuguese spelling), meaning "destroyer (of) boats", in reference to the destructive nature of the root system possessed by some riparian plants.----------------Wet tropical forests are the most species-rich biome, and tropical forests in the Americas are consistently more species rich than the wet forests in Africa and Asia. As the largest tract of tropical rainforest in the Americas, the Amazonian rainforests have unparalleled biodiversity. More than 1/3 of all species in the world live in the Amazon Rainforest.The region is home to about 2.5 million insect species[citation needed], tens of thousands of plants, and some 2000 birds and mammals. To date, at least 40,000 plant species, 3,000 fish, 1,294 birds, 427 mammals, 428 amphibians, and 378 reptiles have been scientifically classified in the region. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone.The diversity of plant species is the highest on earth with some experts estimating that one square kilometre may contain over 75,000 types of trees and 150,000 species of higher plants. One square kilometer of Amazon rainforest can contain about 90,790 tonnes of living plants. This constitutes the largest collection of living plants and animal species in the world. One in five of all the birds in the world live in the rainforests of the Amazon. To date, an estimated 438,000 species of plants of economic and social interest have been registered in the region with many more remaining to be discovered or catalogued.-----------------Deforestation is the conversion of forested areas to non-forested areas. The main sources of deforestation in the Amazon are human settlement and development of the land.Between 1991 and 2000, the total area of forest lost in the Amazon rose from 415,000 to 587,000 km², an area twice the size of Portugal, with most of the lost forest becoming pasture for cattle. In February, 2008, the Brazilian government announced that the rate at which the Amazon rainforest is being cut down has increased significantly over the past few months. During the last five months of 2007, more than 3,200 sq. kilometers (an area equivalent to the size of the state of Rhode Island) was deforested during a time when deforestation would normally drop.-------Not only are environmentalists concerned about the loss of biodiversity which will result from destruction of the forest, they are also concerned about the release of the carbon contained within the vegetation, which could accelerate global warming.------------Environmentalists have stated there is not only a biological incentive to protecting the rainforest, but also an economic one. One hectare in the Peruvian Amazon has been calculated to have a value of $6820 if intact forest is sustainably harvested for fruits, latex, and timber; $1000 if clear-cut for commercial timber (not sustainably harvested); or $148 if used as cattle pasture.