New pollen-analytical researches in Corsica: the problem of Quercus ilex L. and Erica arborea L., the origin of Pinus halepensis Miller forests.

The pollen-analytical study of eight sites (two glacial lakes and six coastal marshes) has been carried out (nine pollen diagrams, 472 pollen spectra). The total absence of Quercus ilex forest in Corsica during the Atlantic and the vegetation contrast existing at that time between the western and the eastern sides of the island are demonstrated. On the western site, Erica arborea constituted the only regional vegetation from the coast up to about 1500 m. Human action is responsible for the establishment of Quercus ilex in this climax vegetation during the Sub-boreal. It is also shown that the only Pinus halepensis forest present today in Corsica has been introduced on the island during the nineteenth century.