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Seedlings of Paulownia (Paulownia sp.) has increasingly appeared in the merchant offers in Poland. However, the knowledge of the technical characteristics of its wood is still insufficient because comprehensive studies of wood properties for this species have not been performed. The main aim of this study was to determine the selected physical and mechanical properties of Paulownia COTE−2 wood. The wood comes from the plantation of Paulownia COTE−2 located in Granada region in Spain. The investigation were carried on 162 samples, according to Polish standards. We analysed the following physical properties: air−dry density, oven−dry density, basic density, proportion of wood substance, wood porosity, total shrinkage of wood in longitudinal, tangential and radial anatomical directions, volumetric shrinkage, coefficients of each of mentioned shrinkage, the anisotropy index of shrinkage and mechanical properties: compression strength, static bending, modulus of elasticity in static bending, including the coefficients of the mechanical properties mentioned before. The results show that Paulownia wood is very light, with the density of 270 kg/m³ and low shrinking (volumetric shrinkage equaled to 7%). The mechanical properties of Paulownia wood are closely related to its density. Static bending equaled to 38 MPa and compression strength parallel to grain amounted to 24 MPa.
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.
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