Population,swidden farming and the tropical environment

Swidden farming has been blamed for the degradation of tropical forest, where it is widely used. However, when the cropping period is short and the fallow period long, the system is shown to be ideally suited to this environment. But this entails a low population density. When this is exceeded, the fallow must be shortened, resulting in loss of forest through grassland invasion, or of the soil itself through erosion or laterization, as shown by modern examples and by the history of the Maya. The degradation blamed on swidden farming is thus not due to the system itself, but to overpopulation, in H.G. Wells's words, "the fundamental evil out of which all the others that afflicted the race arose."This paper is a shortened and updated version of a lecture given in the Department of Biological Anthropology, University of Oxford, on 6 November 1986.