In the middle Rhone valley, various research programs, linked notably with rescue excavations, have profitably increased the amount of available data concerning the palaeovegetation and its use by prehistoric societies. Anthracological analyses of prehistoric settlements give information about the wood used as domestic fuel. Pedo-anthracological analyses of wood charcoal recovered in fire layer « off archaeological site » gives information about the woody vegetation growing next to these settlements. Thanks to phytolith analyses of the same « off-site » layers, we are able to take into account the importance of grasses in the vegetation and to estimate the density of the ligneous cover. The comparison between archaeobotanical data and conte...