The age and history of the French Mediterranean steppe revisited by soil wood charcoal analysis

In the Mediterranean basin, steppe vegetation is considered to be the result either of land clearing in the Neolithic or the result of harsh environmental conditions (shallow soils and/or Mediterranean drought). For the first time, a study was carried out in the French Mediterranean steppe area of the Crau in Southeastern France using soil wood charcoal analysis, a technique in which charcoals found in the soil are identified and dated. According to some authors, an original mixed oak and beech forest may have covered the plain and have been cleared in the Neolithic, or, in the view of other authors, the steppe vegetation may have existed in its present form since the Lateglacial period. A total of 14 soil samples and 23 C14 datings were performed. Our results show that no species of ancient forests dominated by Quercus pubescens and Fagus sylvatica or Q. ilex were present at the end of the Neolithic or during the Bronze Age. Only earlier successional species such as Pinus pinea/halepensis, Phillyrea angustifolia and Prunus sp. were burnt during these periods. The other charcoal identified from the Roman Empire, Middle Ages and Modern periods seem to be better correlated with pastoral settlements than natural secondary succession processes. These results obtained at a local scale confirm those already available from the western Mediterranean, which have shown that human impacts were the determining factors of the evolution of the Mediterranean vegetation during the Neolithic and Bronze age.