Harmful substances, which are present in air, act on plants and forest wood species either directly or as atmospheric precipitation infiltrating the soil, where they change the chemical composition of soil, and in this way they affect the root system of plants and wood species. On the basis of evaluation of results obtained from permanently monitored areas according to forest vegetation stages we can state that soils of lower forest vegetation stages, which are present in the Košice Conurbation, are less affected by acidification. Deciduous trees, which form the main component of the 2^nd and 3^rd forest vegetation stages, considerably participate in general improvement of the health status of forests. We can say that the health status of forests is stabilized in the Košice Conurbation. The average defoliation of deciduous trees is as follows: beech - 18%, oak - 28%, hornbeam - 14%. Hornbeam and oak are the least damaged trees. Fluctuations in individual years are caused mainly by climatic factors.

Map of acidification

Map of defoliation