Fire impacts on vegetation in Central Africa: a remote-sensing-based statistical analysis

The objectives of this study were to understand the role of fires on land-cover changes, and conversely the role of vegetation cover as a controlling factor of fires. The study, which was conducted in a region at the savannah/forest transition in the southwestern part of the Central African Republic, explores the differential impact on land cover of early- and late-season fires and analyses burning regimes as a function of human use of the land. This was addressed using multivariate regression models between maps of land-cover change derived from remote sensing data, maps of burnt areas and a detailed map of ecotypes. In dense forests, burning is strongly associated with land-cover changes, while in savannahs the occurrence of (mostly) early fires does not lead to land-cover change. Fires associated with continuous and fragmented burnt patches have similar impacts on vegetation cover. Dense semi-humid forests in the study area were affected by a high level of burning due to land uses at their peripheries. The results confirm recent findings concerning human control on the timing of burning in savannahs. Early fires fragment the landscape and prevent the spatial diffusion of later damaging fires. Where no human settlements are present, late fires become more prevalent. Finally, the study measured an increase in vegetation cover in a few areas affected by very early burning. Using burnt area rather than active fire data allowed a better analysis of the spatial association between landscape attributes and burning events. (C) 2002 Elsevier Science Ltd. All rights reserved.