Why does deforestation occur in tropical areas?

Hi Hal! Historically the main reason for deforesting tropical areas is to use the land for crops or to raise livestock. This can happen in developing countries when roads are built that allow access to large forested areas that are unclaimed, so it is used for agricultural purposes, for example growing soybeans or logging. More recently, deforestation is occurring at a much faster rate because the land is being used for commercial purposes. This includes, for example, deforestation in Borneo to create commercial-scale palm tree plantations. Palm oil is used in foods and palm trees can be used as a bio-fuel, so there is a lot of money to be made this way.

If you're interested in reading more, here is a NASA article that gives some more details, and here is a BBC Bitesize article outlining some further reasons for deforestation. Hope that helps.