Résumé
The detailed palynological analysis of a core recovered in Lake Ossa, localized in the wet rain forests of Southwest Cameroon, provides new information on the vegetation and climate history of this region during the last 4800 years B.P.. Pollen counts, showing a rich and well-diversified microflora, indicate the persistance of forest environment during all this period. Between around 4800 to 2800 yr BP, the Biafrean and mountain forests were well represented in pollen spectra. Then, at around 2800 yr B.P. (estimated age), a major change in landscape occured indicated by the substitution of the primary forest by a colonizing one rich in pioneer species (Alchornea, Macaranga).. Later there was appearance and extension of the oil palm (Elaeis guineensis) which culminated around 1600 yr BP.