Quantitative reconstructions of changes in regional openness in north-central Europe reveal new insights into old questions

By applying the recently developed model REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) (Sugita, 2007) to pollen data from a large number of sites across Northern Germany and Denmark, we construct maps of regional patterns in landscape openness and in cover abundance of key plant taxa in the cultural landscape of north-central Europe for selected time slices in the Holocene. The results indicate that the pattern of landscape openness across the regions of northern Germany and Denmark prior to the introduction of agriculture was affected by soil conditions and degree of continentality. The 8.2 ka climate event did not lead to a general decrease in tree cover, although some changes in species composition were observed. The early phases of agriculture also had little effect on landscape openness at the regional scale, but later human impact lead to large scale deforestation and development of arable areas, grasslands and of heathlands in the north-western part of the region. The timing and degree of deforestation, and the weight between arable and grazing areas varied in space, partly due to differences in natural conditions, partly due to differences in cultural impact.