This chapter identifies and analyses the causes of deforestation and the effect on the rain forest belt of Nigeria. The rain forest belt of Nigeria probably contains nearly half of all the country's animals and plant species which are unknown in the rest of the world. Changes in economic development, political and social structure as well as prevalent practices have affected the natural state of the rain forest belt. The traditional rotation and shifting cultivation which is prevalent in the forest region of the country and which allows for bush burning, causes deforestation. The burning of forests, and the changes in the organic levels in the atmosphere have an effect on the global heat balance. The remarkable assemblage of living organisms with their habitat are important to administrators as well as to earth scientists, farmers, foresters, as well as plantation growers. It is advisable that forest resources which are highly prized should be intentionally modified only on a small scale.