A farming system based on the clearance of land, cultivation until soil fertility declines, followed by fallowing for up to twelve years, in order to restore the vegetation to its initial condition. Vasconcelos et al. (2002) Appl. Geog. 22, 2 argue that shifting cultivation is ecologically sustainable for the subsistence of small groups. ‘Shifting cultivation is a truly sustainable system, perhaps the only one for humans. It can maintain agricultural production indefinitely with little reliance on external inputs when population levels are low—roughly no more than one person per 2 hectares of agricultural land’ (C. A. S. Hall 2000). Uhlig et al. (1994) Ecol. Studs 101, 145 find that shifting cultivation alters carbon-release estimates.