Variability of the defects distribution round wood in mature pine stands

The aim of the research was to determine the impact of selected habitat and age features on the qualitative properties of Scots pine (Pinus sylvestris L.). The research was carried out on forest stands from the Olesno, Wymiarki and Kalisz Pomorski forest districts (western Poland). The collected data provided information on technical and dimensional properties as well as quality classes for logs from Scots pine stands. The severity of the occurrence of seven basic wood defects, identified on the perimeter and length of the model log was identified and described. The collected data was used to determine the distribution of defect groups. For distributions of defect groups, normal distribution criteria were met. For the Scots pine assortments, the ANOVA showed that the hypothesis of the occurrence of an equal number of defects on the side of the logs in three separated classes of WA0, WB0 and WC0 of the quality of the raw material should be rejected. For the Tukey test, the results indicate that there is no reason to reject this hypothesis. The obtained p−value in this case is 0.09 for WB0 and WC0. There was no influence of the diameter of the logs and the habitat on the number of defects. Number of defect groups is correlated with the distance from the butt in Kalisz Pomorski and Wymiarki forest districts but not in Olesno. In that case the increase in the number of defect groups has its maximum in the zone of 6−8 m of the log length