Pedoanthracological contribution to the study of the evolution of the upper treeline in the Maurienne Valley (North French Alps): Methodology and preliminary data

Wood charcoal contained in the soil (pedoanthracology) was identified for a study of the development of the present-day treeline in the Maurienne valley (Savoie, France). The paper is divided into two main parts. The first part presents the pedoanthracological method, which is based on the identification and the stratification of wood charcoal in soils. It is a new tool that provides a high spatial resolution analysis of fire-affected ligneous vegetation and their evolution. In the second part, the analysis of charcoal from four sites located at different elevations and positions with respect to the treeline is presented. Pinus cembra charcoal clearly dominates all the samples. The vegetation becomes more open in the younger charcoal assemblages located in the upper part of the profile. This phenomenon is attributed to the repeated effects of anthropogenic fires. The significant fire phase is dated to the Subboreal period in the Saint-Michel-de-Maurienne catchment area. The charcoal evidence of local forest clearance agrees with the regional palynological record.