Deforestation. View of colonists clearing rainforest from along the banks of the River Amazon (upper right) in Ecuador. This systematic clearing of trees and vegetation from the rainforests has raised concern that countless plant and animal species could be made extinct. There are also worries that the lack of oxygen- producing vegetation in this area could contribute to global warming, due to increased levels of carbon dioxide in the atmosphere. Apart from the commercial use of timber, and development of urban and agricultural land, foreign oil companies have been sold massive areas of forest, with subsequent large-scale destruction of vegetation.