Résumé : The mosaic forest characterising the municipalities of Banté-Glazoué-Ouessé (Collines district) in Benin's Sudano-Guinean zone is one of the country's main sources of agricultural produce and charcoal. These mosaic forests are being degraded in different ways. A study of their dynamics over space and time, based on interpretations of Landsat-type imagery (MSS 1972, TM 1986 and ETM+ 2006), using a geographic information system and landscape ecology tools, was conducted to support a possible forest restoration programme. The study results were applied, by means of transition matrices and spatial structure indices, to assess changes arising from agricultural practice. Four main spatial transformation processes were identified and quantified over the 34-year period (1972 to 2006) chosen for the study: (i) savannah formation, (ii) deforestation, (iii) development of agricultural activities and, (iv) forest restoration. Over this period, the spatial structure dynamics were dominated by slash-and-burn clearing followed by the enlargement of field and fallow patches and tree plantations, aggregation of savannah, bare soil and urbanised patches and the elimination of forest patches.