The quality of alder raw material from stands growing in different habitats

In the present study, an attempt was made to determine the quality of alder raw material growing in different habitat types of forest. The research work was conducted in the Włoszczowa Forest District in Poland. Measurements were taken in 8 stands growing on three forest site types: alder moist forest, alder-ash moist forest, moist forest. In the selected stands, 4-are sample plots were established. In each circular sample plot, DBH and height of all trees in the plot were measured. In the selected trees, the quality of the wood and the type of defects that influenced the wood classification result were determined in the trunk butt end (at a length of 4 metres). In every other plot, a core was taken from a height of 1.3 m in a randomly selected tree to determine the presence of latent defects. The black alder tested on each site achieved very good technical quality. The volume share was dominated by veneer wood, the most of which was estimated in moist forest. Very small amounts were found of lower quality classes. It was found that in less humid habitats than typical alder forests, black alder produces better quality wood. However, once the borings were taken into account, the proportion of each quality class changed dramatically. Hard rot and soft rot degraded the best quality classes to lower quality classes. The share of the best quality wood fell from 60% to 7.57%, while the share of the worst quality wood increased from 5.94% to 40.57%.