Deforestation has both environmental and economic impacts. Define deforestation, any environmental impacts and economic causes of deforestation.

Deforestation is defined as the act of clearing large areas of forest or woodland, usually for economic gain and not as a means of natural resource management.
These impacts can be environmental or economic, sometimes both.
Environmental impacts may include contributing to climate change. This is due to trees storing carbon and removing carbon dioxide from the atmosphere, a well known greenhouse gas. Deforestation results in the cutting down of trees, leading to less carbon being stored and less carbon dioxide being removed. Removing trees may also result in loss of habitat for local wildlife
More detail: Removal of trees leads to enhanced levels of surface-run off, leading to greater chance of flooding in the immediate local area. This in turn can alter a river's behaviour as it flows over land.

Economic causes can vary depending on the country in which the deforestation is occurring. Common causes are mineral extraction, selling raw material (trees) or clearing the land for agricultural use.