EN
The aim of the study was to compare the tree−ring width, latewood share and density of spruce wood from the mature stands occupying different forest habitats. 12 study plots were located in the north−eastern Norway spruce range in Poland (lowlands), whereas 16 in the south−western one (mountains). On the lowlands we chose stands growing on fresh mixed coniferous, humid mixed coniferous, fresh mixed deciduous and fresh deciduous habitats, while in the mountains we selected alpine coniferous, mountain coniferous, mountain mixed coniferous, mountain mixed deciduous and mountain deciduous ones. On each study plot we chose 15 trees according to the Draut method and took increment cores with the Pressler borer. We measured tree−ring and latewood width and then divided the cores into 2−cm sections, for which the relative wood density was determined. The tree−rings were the widest in trees from fresh mixed coniferous (lowlands) and mountain mixed deciduous (mountains) sites, whereas the narrowest ones were observed in trees growing on fresh mixed deciduous and mountain mixed coniferous sites. We found statistically significant difference (p<0,0001) between analysed habitats. The latewood propoprtion showed the opposite dependence than the tree−ring width – wood from fresh mixed coniferous and mountain mixed deciduous sites was characterized by the lowest proportion of latewood, whereas the wood from fresh mixed deciduous and mountain mixed coniferous sites had the highest share of latewood. In this case the differences between the two analyzed groups of stands were also statistically significant. As far as the wood density is concerned, the highest values were found for trees occupying fresh mixed deciduous and mountain mixed coniferous sites and the lowest in trees growing on humid mixed coniferous, fresh deciduous and mountain deciduous sites. The differences between them was also statistically significant. Next, the stands were divided into two groups: coniferous and deciduous sites. It was found that trees from lowland coniferous sites have wider rings than the ones from deciduous sites. In the mountainous region the opposite dependence was observed. The latewood share and wood density was lower in lowland coniferous sites in comparison to deciduous ones. The results were reverse in the mountainous sites.