Norway Spruce dynamics in NE Poland at the Middle-Late-Holocene transition: Insights from quantitative landcover reconstruction

Norway spruce is one of Europe’s most significant trees, with a millennia-long role crucial for maintaining values of forests. Yet its migration, especially at its current range limits, is not fully understood. The paper presents the results of palynological research on the temporal spread of spruce in NE Poland between ca. 5500–2300 cal BP. The significance of our study lies in the fact that we used pollen records to reconstruct the vegetation using both pollen percentages and a quantitative vegetation reconstruction (REVEALS) model for the first time in this region of Poland. Based on percentage pollen data, we have shown that due to the specificity of the studied sites and local conditions, the migration process may not have been synchronous. However, using the REVEALS model allowed us to determine time intervals for the entire study region where the spruce spread and retreated, along with the correlation of these changes with climate change and human impact on vegetation. Spruce increased its importance ca. 5500 cal BP, and at ca. 5300–5100 cal BP it has been a part of the local stands, which may have been related to the 5.2 ka cooling. The next impulse for the spread of spruce was the 4.8 ka cold event. Another increase in the spruce area begins at ca. 4300–4100 cal BP and was probably associated with 4.2 ka event. Conditions promoting the spread of spruce also occurred at ca. 3500–3300 cal BP and were synchronous with the climate oscillation dated at ca. 3400 cal BP. The role of spruce decreased at 2900–2700 cal BP. It may have been caused by anthropogenic factors despite the climate event of 2.8 ka. Then, spruce was more common, about 2700–2500 cal BP, during periods of stronger anthropogenic pressure associated with intensified colonization at the end of the Bronze Age.