A Spatiotemporal Model of Shifting Cultivation and Forest Cover Dynamics

Shifting cultivation is the primary means of livelihood for subsistence farmers throughout the humid forests of the tropics. They rely on the forest landscape as a source of fertile land to sustain their livelihood. Sustainable use of the resource base requires long periods of fallow and the ability to move the zone of active cultivation from one location to another over time. At the individual patch or field level, shifting cultivation is essentially a resource extraction problem somewhat akin to a pulse fishery - intensive use of the stock of soil fertility for a short period followed by a long idle period to allow regeneration of the stock. This paper describes a spatiotemporal model of resource extraction adapted to the use of forest resources by shifting cultivators. In contrast to other models of spatial resource exploitation, decision criteria depend on a nonseparable agricultural household model extended to accommodate both the temporal and spatial dimensions. The paper focuses on the theoretical issues related to modelling shifting cultivation. It concludes with a brief discussion of the development and implementation of a simulation model based on the theoretical approach described herein