Ecological researches on the French Atlantic oak forest

Abstract

This note deals with the regressive evolution of the oak forest towards the heath land, in an Atlantic climate together with the simultaneous evolution of the soil (podzolisation). From this point of view we have compared this double evolution in three phytogeographical sectors which are different climatically and geologically, the Ligerian sector (Loire basin), the Armorican sector (Lower Brittany) and the subsector of the “Landes” of Gascony; associations and soils can be classified in those three sectors in three main groups: the clomatic oak forest (Quercetum ilicetosum) on brown lightly washed soil or on young soil; the degraded oak forest (Quercetum occidentale) which on podzolic soil; and lastly the heath is to be seen chiefly on podzol. Each association and the corresponding soil present a slightly different aspect according to the sector under consideration.