An advancing process of ageing of stands in Poland and Europe allows for predicting and increasing in the supply of large-dimension timber. The research compares selected qualitative characteristics of the timber of trees with large breast-height diameters (equal to or larger than 40 cm) with those of thinner trees on the example of Norway spruce from the region of the Beskidy Mts. A group of thicker spruce trees was characterized by a higher overall share of trees with wood defects, including visible knots and symptoms of overgrown knots as well as a smaller share of trees with injuries, rot and curvatures in comparison with the thinner ones. The absolute size of rot on the cross-section of the stem was larger in thicker trees. They were also characterized by a smaller average width of annual rings. The groups compared did not differ significantly as to the height of location of defects situated as first from the stem base.

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