The variation of terrestrial carbon storage at 6000 yr BP in Europe: Reconstruction from pollen data using two empirical biosphere models

International audienceTwo empirical biosphere models, the Osnabruck Biosphere Model (OBM) and a simple model based on evapotranspiration (AET model), were used to reconstruct the terrestrial carbon storage from pollen at 6000 yr sp in Europe. The pollen-based climatic reconstructions of Guiot et al. (1993) and the ecosystems reconstruction of Peng et al. (1994) provide the input data of the two models, i.e. annual temperature, annual precipitation, actual evapotranspiration, potential evapotranspiration and ecosystems with a spatial resolution of 0.50 longitude/latitude. For the region considered, our results suggest that there are no significant variations in the terrestrial carbon storage between 6000 yr sp and present due to a compensation of the forest extension towards the north by the replacement of conifer forest (with higher carbon) by deciduous forests towards the east. This is consistent with the recent results of Foley (1994) based on climate and biosphere models. The comparison of the two model results with those obtained from the carbon densities of Olson er al. (1985) and Zinke et al. (1986) shows a large similarity for vegetation but a higher value of the OBM for the soil