EN
The paper concerns the comparative analysis of changes occurring in macroscopic, as well as in microscopic structure and density of wood of scotch pine, growing in three zones, differing according to industrial effluent hazard. The studies were carried out on 8 surfaces, founded in homogenous pine stand, of the age from 80 to 100 years. The surfaces were located in three zones of different industrial effluent hazard (0, II and III), determined on the base of tree-crown damages. On every surface 15 trees were analysed. It was documented that in pine stands, growing in the range of industrial effluent, the life of the trees and their growth dynamics were lowered, also changes in wood structure and its properties occurred. The changes were correlated with the degree of pollution hazard (tree-crowns damages). It was possible to determine the character of these changes and their succession in every zone. In zone II of hazard (of average damages) the decreasing of annual ring growths, below determined indexes of critical values, correlated with decreasing of about 4% of late wood and also correlated with decreasing of about 10% of wood density. In this wood, the gum ducts were much numerous than normally of about 25% (Table 2 and 3). In zone III оf hazard (of serious damages) the decreasing of annual ring growths progressed, whether the decreasing of wood density was similar to that of the zone II: on the level of 10%. In zone III essential changes in dimensions of vascular tracheids were observed. The most visible differences were observed in narrow growths, up to 0.5 mm. The lengths of vascular tracheids decreased in this zone of about 35%, whether the surface of their cross-sections of about 15%. In tree populations, growing in zone III of hazard, much higher variability in wood features was observed, than in tree stands growing in zone free of pollution. Such individual differentiations of trees reactions on industrial effluents should be taken into consideration when selecting the trees for industrial areas.