Abstract: Afforestation on formerly cultivated or abandoned agricultural land is a common strategy to increase forest areas and enhance carbon sequestration. Deep soil ploughing before afforestation improves soil conditions, facilitating tree growth and carbon storage. This study assessed the growth and biomass parameters of Pinus sylvestris in 10- and 20 years old plantations established on deeply ploughed and non-ploughed soils in Lithuania. Biomass allocation and carbon and nutrient concentrations including N, P, K, Ca and Mg were analysed in aboveground biomass components. Deep ploughing in the 10 years old stands negatively impacted vertical growth and stem development but did not significantly affect overall biomass accumulation. In contrast, in the 20 years old stands, deep ploughing resulted in taller trees with larger diameters and higher biomass accumulation compared to non-ploughed sites. Biomass distribution within tree canopies varied between ploughed and non-ploughed sites, indicating diverse effects of deep ploughing. Carbon and nutrient concentrations in biomass components showed site-specific variations, with deep ploughing influencing carbon concentrations in needles and stem bark. Overall, deep ploughing showed potential for enhancing tree growth and biomass accumulation, with implications for carbon sequestration in forest ecosystems. These findings help us understand the impact of an alternative soil management practice, deep ploughing, on forest development and carbon dynamics.

Key words: Deep tillage, Scots pine, Tree height, Biomass, Carbon, Nutrients