Deforestation. View of rainforest being burned to clear land for cattle. The 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 loss of oxygen-producing vegetation could contribute to global warming, due to increased levels of carbon dioxide in the atmosphere. Forests are cut down not just for timber, but also to clear land for crops, grazing farm animals (as here) and, in some areas, oil drilling. Photographed in Para State, Brazil.