“Thermophilous” Trees in the Lateglacial Vegetation of the Eastern Baltic: New Questions for an Old Issue

The results of a recent palynological study of the Kulikovo section (southeastern Baltic) allow us to elaborate on issues of the presence of pollen from the “thermophilous” trees (Picea, Alnus, Corylus, Ulmus, Quercus, Tilia, Fraxinus) in Lateglacial sediments. The research shows their continuous presence throughout the interval of 13.9–12.5 ka with a total contribution from 7% to 17%. Comparing the results with regional palynological data revealed certain similarities and patterns, which are not sufficiently explained by contamination by ancient redeposited material. These taxa belonging to the hemiboreal plant group were most probably part of the Lateglacial vegetation along with subpolar and boreal plants. This correlates well with regional paleoclimate reconstructions, assuming that, during the major part of the Lateglacial, July temperatures were comparable to modern average temperatures, which range from +16.5 to +18 °C. Inclusion of hemiboreal tree vegetation in paleoreconstructions will offer an updated picture of the dynamics of the natural environment and increase the accuracy of paleoclimatic reconstructions based on palynological data, allowing us to obtain more accurate temperature values of the climate of the past.