In many countries people don't have gas or electricity and they have to use firewood for fuel and they continue to cut down huge amounts of trees. In many developing countries land is being cleared for farming, highways, and urban development. Developed countries contribute to deforestation in under-developed countries. Many developing countries cut down and sell timber to get money easily. There are many negative effects of deforestation.
Soil salinity is one effect which leads to the destruction of native trees and vegetation.
Soil erosion and the loss of top soil are also problems which lead to increased droughts and floods. Many creatures whose habitat is in the forest find themselves homeless. Also when trees are cut down there is a change in the atmosphere because there is less oxygen and more carbon dioxide in the air. There are many benefits which the forests and rainforests provide us with like food, chemicals, and medicines. Because of the large number of insects in the rainforest, the plants have to defend themselves and we can manufacture those natural insecticides to be used on domestic crops.