This work contains the preliminary results of research into the technical quality of the wood from Scots pine trees of diverse genetic origin, grown on an experimental plot at the Forest Experimental Station in Rogów. The following are the parent stands, numbered: 5 (the Tucholskie Forest 130 m a.s.l.), 7 (the Napiwodzko–Ramuckie Forest 145 m a.s.l.), 10 (the Piska Forest 145 m a.s.l.), 12 (the Biała Forest 95 m a.s.l.), 13 (the Namysłowsko–Ostrzeszowskie Forest 190 m a.s.l.), 15 (the Knyszyńska Forest 165 m a.s.l.), and 16 (the Nowotarskie Forest 590 m a.s.l.). The tested wood was obtained in 2018 from trees aged 52 years. The research material came from 100 trees in total. After felling, two logs approximately 0.5 m in length were cut from each tree. The height on the tree from which the material was taken ranged from breast height (1.3 m) to approximately 2.5 m. Next, planks were cut from the logs in a north–south direction; these were precisely described and then left to season. The work included the measurement and statistical analysis of one physical property, wood density (kg/m³), and of the following mechanical properties: compressive strength along the fibres, Rc₁₂ (MPa); static bending strength, Rg₁₂ (MPa); modulus of elasticity under static bending, Eg₁₂ (MPa); and indices of strength quality of the tested mechanical properties, JRc₁₂, JRg₁₂, and JEg₁₂ (km). The origin of the logs was shown to have a significant influence on wood density, compressive strength, static bending strength, and modulus of elasticity under static bending. The highest mean density was found for trees originating from stand 10 (537 kg/m³). The highest values of compressive strength were obtained for trees originating from stands 5 (45 MPa), and the highest static bending strength and modulus of elasticity under static bending were obtained for trees originating from stand 12 (102 and 9825 MPa, respectively).

The work detailed here in the context of the above project sought to determine changes in the gene pool (at the DNA level) in a stand of Scots pine (Pinus sylvestris L.), under the influence of various kinds of forest-tending cuts. The experimental area on which the research was focused is located in Poland’s Ostrów Mazowiecka Forest District. Genetic structure was specified using five nuclear SSR sequences and six chloroplast SSR loci, while the five thinning variants trialled were sanitation cutting, low thinning of 30% intensity, schematic thinning, selective thinning and destructive lumbering. The control variant was left untreated. It was virtual rather than real-life thinning that was pursued, using the ForestSimulator BWINPro program. Changes in the structure of the stand after a further 10 years were also simulated. The different thinning variants were shown to cause change in the gene pool and level of genetic diversity of trees in the study area. In terms of maintaining genetic variability in the stand, the least-favourable method proved to be thinning from below. Destructive selection cutting was in turn most beneficial in terms of the preservation of genetic structure, with the reduction in rare alleles being more limited than in any other analysed variant. It was with the selective thinning variant that the final number of trees, stand structure and level of genetic variation resembled the situation in the control most closely. This suggests that selective thinning provides for a rather accurate replication of processes occurring in nature.

The analysis of population variability usually concerns the adaptability of trees to changing climatic conditions and their timber production possibilities. It is already known that several phenotypic and genotypic features determine the adaptation possibilities of a population and every population of a given species may have different adaptability to climatic conditions. The assimilation apparatus is an important phenotypic feature that has a large impact on the functioning of tree organisms and their adaptability. Scots pine, which covers vast areas of Europe, is a very important species in the context of ecosystems’ sustainability preservation, especially in the era of global warming. Therefore, in our research, the inter-population and individual variability of morpho-anatomical features of shoots and needles were analyzed. Nine national origins of Scots pine (three populations each from northern, western, and central Poland), which are a part of a 50-year provenance experiment, were compared. Fragments of one-year-old shoots (5 cm long) with needles were collected from the top parts of tree crowns. An extensive analysis of the morphological parameters of the needles (length and width, density, dry mass) and the anatomical features of the shoots (thickness, the share of bark, wood, and pith) was performed. Our surveys showed that the differences between populations are much greater than between regions. The western pine populations, which have shown the highest volume of wood per ha, had the thickest shoots but the lowest dry mass. The northern populations, highly valued for the very good technical quality of wood, had thin shoots. Pine trees from central Poland had the highest density and dry mass of needles and the highest share of wood in shoots.

Scots pine (Pinus sylvestris L.) exhibits substantial variation among provenances in growth and wood properties. This study investigated provenance-related variation after nearly six decades of growth under common-garden conditions and examined relationships between tree growth, wood properties and climatic characteristics of provenance origins. The study was conducted in a provenance experiment established in 1966 at the Rogów Forest Experimental Station in central Poland, comprising 16 provenances and five experimental replicates. Tree height, crown length, trunk volume, diameter at breast height (DBH), wood density, dynamic and static modulus of elasticity (MOE_dyn and MOE_st), modulus of rupture (MOR) and compressive strength (CS) were analysed. Provenance significantly affected all traits except MOE_dyn, whereas experimental replicate significantly affected most traits. Correlations calculated across individual trees were generally weak, while provenance-specific relationships varied substantially in strength and direction. At the provenance level, tree height and DBH showed the strongest associations with climatic characteristics of the provenance origins, particularly altitude, mean annual temperature, precipitation, aridity and growing season length. Selected mechanical properties also showed moderate climatic associations. The results demonstrate persistent provenance-related differentiation under common environmental conditions and indicate that growth performance alone cannot reliably predict wood quality. However, the climatic associations should be considered exploratory and do not constitute direct evidence of local adaptation.

One adaptive silvicultural strategy to address the increasing frequency and severity of climate extremes is the promotion of genetic material best suited to a changing environment. Using a long-term provenance trial established in 1966 in central Poland, we evaluated how climate humidity at the parental site (provenance origin) influences individual-tree growth–drought resilience trade-offs in Scots pine (Pinus sylvestris L.). Stem discs from 240 trees representing 16 provenances were initially assessed, of which 202 trees were retained following cross-dating and quality control. Drought responses were quantified using complementary growth resilience indices for major drought events identified using the Standardized Precipitation–Evapotranspiration Index. Mixed-effects models followed by Type III Wald chi-square tests and Sidák-adjusted pairwise comparisons revealed significant provenance-level differences in drought responses. Structural equation modeling showed that parental-site climate directly and indirectly affected drought resistance through its influence on relative tree size. Trees from provenances originating in more water-rich environments tended to be smaller but exhibited higher resistance, indicating a potential trade-off between growth and drought tolerance. Relative tree size was also negatively associated with resilience, whereas recovery and relative resilience were not significantly associated with provenance climate or relative tree size. These findings indicate that provenance climate is associated with drought resistance in Scots pine, with tree size emerging as an important mediator of this relationship.