Wpływ siedliska na wybrane właściwości strukturalne i fizyko-mechaniczne drewna brzozy brodawkowatej (Betula pendula Roth.)

摘要

The aim of the research was to determine the habitat-related variation in the selected structural and physical -mechanical properties of silver birch. Two sample plots were established in the territory of the Biała Podlaska Forest District in eastern Poland. Samples for measurement were taken from the plots with trees aged 45-50 years growing in the fresh deciduous (Lśw) and fresh mixed deciduous (LMśw) forest habitats. The following properties were subjected to statistical analysis: the average width of annual rings, wood density determined for the samples of 20×20×300 mm, 20×20×30 mm, and 30×2.66×0.1 mm in size (the last dimension parallel to grain), tensile strength parallel to grain, compression strength parallel to grain, static bending, modulus of elasticity in static bending and the coefficients of tensile strength parallel to grain, compression parallel to grain, static bending, and modulus of elasticity in static bending. The research confirmed a significant effect of the habitat on the mean values of birch wood density for all examined sample sizes, tensile strength parallel to grain, static bending and modulus of elasticity in static bending. No significant effect of the habitat on the mean values of annual ring width, tensile strength parallel to grain and the coefficients of tensile strength parallel to grain, compression strength parallel to grain, static bending and modulus of elasticity in static bending for birch wood samples was found.%The aim of the research was to determine the habitat-related variation in the selected structural and physico-mechanical properties of silver birch trees. Two sample plots were established in the territory of the Biała Podlaska Forest District in eastern Poland. Samples were taken for measurement from the plots with the trees aged 45-50 years growing in the fresh deciduous (Lsw) and fresh mixed deciduous (LMsw) forest habitats. These are habitats in which silver birch in Poland occurs most frequently as a dominant species both in terms of area and volume. The following properties were subjected to statistical analysis: the average width of annual rings, wood density determined for samples sizes: 20×20×300 mm, 20×20×30 mm, and 30×2.66×0.1 mm (the later parallel to grain), tensile strength parallel to grain, compression strength parallel to grain, static bending, modulus of elasticity in static bending and the coefficients of tensile strength parallel to grain, compression parallel to grain, static bending, and modulus of elasticity in static bending. The research confirmed a significant effect of the habitat in which birch trees grow on the mean values of birch wood density for all three examined sample sizes, tensile strength parallel to grain, static bending and modulus of elasticity in static bending. No significant effect of the habitat on the mean values of annual ring width, tensile strength parallel to grain and the coefficients of tensile strength parallel to grain, compression strength parallel to grain, static bending and modulus of elasticity in static bending for the birch wood samples was found. Wood density for all sample sizes as well as tensile strength parallel to grain, compression strength parallel to grain, static bending and modulus of elasticity in static bending decreased with the decrease in the fertility of the Lsw and LMsw forest habitats. The mean width of annual growth rings slightly increased with the decrease in the fertility of the Lsw to LMsw forest habitats. The coefficients of tensile strength for all examined strengths attained similar values in the Lsw to LMsw forest habitats. The Lsw forest habitat has higher mean values of wood density and mechanical properties. However, the mean values of all coefficients of tensile strength of mechanical properties of wood in the examined LMsw and Lsw forest habitats are very similar which indicates that birch wood in the LMsw forest habitat with the lower mean density and strength values is a potentially better construction material in the plywood industry as well as for the production of sports equipment and modelling. The highest density values of a single silver birch wood sample were found in the Lśw forest habitat amounting to 842.57 kg/m~3 for the sample 20×20×300 mm, 836.29 kg/m~3 for the sample 20×20×30 mm and 925.39 kg/m~3 for the sample 30×2.66×0.1 mm. The observed changes in the mean values of structural and physical-mechanical properties of silver birch wood can serve a more rational economic use of this valuable material. Significant differences in some of the analysed traits confirm the need to conduct broader studies broader studies on the selected habitat-related structural and physical-mechanical properties of silver birch wood also in other resource bases of this species in Poland.