Wieloczynnikowa analiza zmienności gęstości drewna brzozy brodawkowatej (Betula pendula Roth.)

The aim of the research was to determine the variation in wood density of the silver birch in north−eastern Poland depending on the location (geographic region), age and interaction between these two factors, as well as the diameter of trees. Samples were taken for measurement from twelve sample plots with the trees aged 45 and 70 years growing in the fresh forest habitat. Statistical analysis was applied to the mean wood density values calculated for wood samples of the sizes: 20×20×300 mm, 20×20×30 mm and 30×2.66×0.1 mm. The study confirmed a significant effect of the location, simultaneous effect of the location and age, as well as the diameter of trees on the mean values of silver birch wood density for all examined sample sizes. No significant effect of the age on the mean values of birch wood density for all examined sample sizes was found. The mean value of wood density for the sample size 30×2.66×0.1 mm was the highest for the whole sampled material, amounting to 699.29 kg/m3, the wood density for the sample size 20×20×300 mm was lower – 681.04 kg/m3 and for the sample size 20×20×30 mm it was the lowest – 679.76 kg/m3.