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The aim of this paper is to investigate and compare structural, mechanical and physical properties of wood of Norway spruce growing on experimental plot in Rogów (central Poland). The planting material consisted of seeds sourced from six selected provenances. Three of them originated from lowlands, while the others have mountain origins (tab. 1). The plot was established in 1975 and the wood was harvested in 2010. Wood samples were prepared and measured according to the Polish Standards describing those procedures. The following properties were subjected to the research and statistical analyses: average tree−ring width, share of latewood, wood density, compression strength parallel to grain, static bending, modulus of elasticity in static bending and the coefficients of compression strength parallel to grain, static bending, and modulus of elasticity in static bending. Results of the investigation were correlated in the frame of each provenance. Wood density determines values of compression strength parallel to grain, static bending and modulus of elasticity in static bending. The higher wood density, the higher values of the mechanical properties. Ordering provenances by the wood density demonstrates the same results as ordering by values of compression strength parallel to grain. The high values of density and mechanical properties prove good technical quality of the analysed wood. The structural properties (the average tree−ring width and the share of latewood) are correlated to the wood density as well. They are additional features to describe wood quality, but are not as accurate as the mechanical properties. The quality of wood from all investigated provenances is high, what makes impossible to distinguish wood from selected provenances using applied features. Wood from Nowe Ramuki and Kartuzy (i.e. lowland) provenances has the best quality parameters, while one from Istebna Bukowiec and Stronie Śląskie (mountain) provenances demonstrated the worst properties (tab. 2). The results do not prove the opinion about the best quality of Norway spruce wood originating from the mountains.
The main aim of study was to present the stock and structure of deadwood in different site conditions. In total. sixteen study plots were established on wet broadleaved forest (Lw) and riparian alder forest (OlJ) sites. The objective was to determine the carbon accumulation in lying dead trees. The investigation was performed in the Czarna Rózga reserve in Central Poland (50°59‵37N; 20°01‵5E). All live and dead trees were measured on each plot. The species of both live and dead trees were identified as well, and the decay class of the dead trees was assessed. Additionally, samples of different species wood from lying logs in five decay classes were taken for carbon content determination. The study was carried out in the spring of 2017. The average stock of deadwood in the Czarna Rózga reserve on the wet broadleaved forest site amounted to 47 m³/ha, while on the riparian alder forest site it equaled 52 m³/ha. The high stock of deadwood can be explained by the slowdown of decay processes by humidity and anaerobic conditions. Ash was the dominant species in the deadwood pool. Regardless of the site conditions (Lw or OlJ), the stock of ash deadwood was several times higher than the stock of live trees this species. The greater carbon stock in lying dead trees was recorded in riparian alder forest.
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