Development of beech necrotic disease in the growing phase of maturing stand under air pollution stress
The paper compares the state of the necrotic disease of beech stem bark on three research plots in 2004 with 1995. The investigated objects were three research plots of beech in the growing phase of maturing stand in Central Slovakia subjected to different air pollution stress. Larger negative changes in the beech necrotic disease were recorded on a plot situated in the close vicinity (1.5 km) of the aluminium plant. We consider the permanent negative influence of pollutants from the aluminium plant on the vitality of trees as the main cause of the negative changes. The health state of beech (defoliation) on this research plot was also permanently significantly worse than on the two other plots situated at a larger distance from the pollutant source (7 and 18 km respectively). The state of necrotic disease on the plot situated at the distance of 7 km was significantly better in 2004 than in 1995. This difference could result from the age of beech trees being lower by 15 years than on the plot distant 18 km from the pollutant source where the state of necrotic disease has not changed. On none of the studied plots was the tree defoliation influenced by the current state of the necrotic disease of beech stems.