Summarize the boserup thesis which describes changing agricultural land use

The Boserup thesis posits that population change in a particular area causes a change in the overall intensity of agricultural production. This is quite understandable, since an increase in population will bring with it the need for more food and as a consequence, a shift to more intensive land use to satisfy the growing population. According to Boserup, the change in land use among shifting cultivators starts with forest fallow, brush fallow, short fallow, followed by annual cropping, and finally multi-cropping.