The National Aeronautics and Space Administration lists agricultural expansion, wood harvest, urbanization and infrastructure creation as the direct causes of deforestation. Converting forested lands for agricultural use is by far the largest cause of deforestation. Conversion to agricultural lands primarily occurs in developing nations and is carried out by subsistence farmers, while other types of deforestation are triggered by economic growth.
NASA states that poverty is an underlying cause of deforestation in many developing nations. Poverty can drive residents into the forest as they seek out better ways to provide for themselves and their families. Economic factors play a large role in deforestation. Accommodating growing populations may require infrastructure expansion into forested areas, and timber is required to fulfill lumber and fuel needs. The global demand for tropical lumber and other wood products is also increasing, tempting entrepreneurs to quickly deforest lands by clear cutting instead of choosing more sustainable methods of timber harvest.
According to NASA, the creation of roads through forests frequently precedes other causes of deforestation, since they provide increased accessibility. Logging operations are often responsible for the first round of deforestation in a newly accessible forest. After marketable timber is removed, farmers, ranchers and builders clear the remaining trees to make room for new pastures and crop fields or buildings.