Deforestation is the clearing of forests on a large scale. In tropical areas it has happened to provide land for cattle and rice fields, and to grow crops from which biofuels can be made.
The environmental effects are serious. Tropical forests contain a huge number of species. When the trees are cut down, the habitats are lost, so many species die out and biodiversity falls.
Trees take in carbon dioxide for photosynthesis. With fewer trees, less carbon dioxide is removed from the atmosphere. If the trees are burned, or if they decay, they release carbon dioxide into the atmosphere. Deforestation therefore adds to global warming.