A spatially precise study of Holocene fire history, climate and human impact within the Maurienne valley, North French Alps

1 If, within a vegetation type, fire regimes are climate dependent, then fire patterns should be synchronous at regional scales. If they are not synchronous, then fires may be dependent on local processes such as human-induced disturbances. 2 Two fire chronologies were developed using 34-radiocarbon dating measured by accelerator mass spectrometry (AMS) from wood charcoal buried in soil. These charcoal fragments were sampled in two study sites 10 km apart in the Maurienne valley (Southern Vanoise massif, Savoy, France). 3 Asynchronous temporal fire patterns were seen at Aussois and Saint-Michel-de-Maurienne. This demonstrates the dependence of fires on local- or stand-scale environmental forcing; any direct relationship with climate is therefore rejected. 4 Slash-and-burn practices are probably the main source of Holocene fires in the Maurienne valley. However, deforestation did not occur throughout a site in any period, nor simultaneously at the same elevation in two different sites 10 km apart. The cultural landscape was shaped as early as the Neolithic and the Bronze Age, between 6000 and 3000 sp. 5 Deforestation at both study sites probably occurred in many stages in many small areas. The fire intervals were c. 500-1000 years. Deforested areas increased in extent over 2000-4000 years, until the present-day cultural landscape was established. This process stopped c. 2500 sp at Saint-Michel-de-Maurienne but is still active at Aussois.