Végétation et climat dans les forêts du Sud-Ouest Cameroun depuis 4 '7'10 ans BP : analyse pollinique des sédiments du Lac Ossa

The detailed palynological analysis of a core recovered from Lake Ossa, situated in the wet rain forests of South West Cameroon, provides new information on the vegetational and climatic history of this region during the last 4,770 years BP. Pollen counts, showing a rich and well-diversified microflora, indicate the persistence of forest environment throughout this period. Between around 4,770 and 2,730 BP the Biafrean and mountain forests were well represented in pollen spectra. Then, at around 2,730 BP (estimated age), a major change in landscape occurred indicated by the substitution of the primary forest by a colonizing one rich in pioneer species (Alchornea, Macaranga). Later there was extension of the oil palm (Elaeis guineensis) which culminated around 1,600 BP.