State of nutrition of trees and stands often indicates processes at the ecosystem level. Insufficient mineral nutrition of the stands can affect significantly tree vitality, and, in connection to air pollution, it can increase its effect. Contrarily, high amount of some elements in leafs and needles can intoxicate the plant or it can confirm air pollution level. Unsatisfactory conditions of the mineral layer in the root zone can affect negatively the balance of mineral nutrition of the forest stands.
Sampling and analyses of the leafs and needles is thus very important. Analyses are to be done in regular intervals, to describe relationships of the site conditions development and state and development of mineral nutrition. Number of samples has to be sufficient to see possible trends in mineral nutrition, and to minimize fluctuation of values and non-reliable conclusions. See the Manual.
Taking of the samples of assimilation organs within the level II plots, their preparation and analysis were done in harmony with the Manual ICP Forests, Part VI – Sampling and Analysis of needles and leaves.
Analyses of the samples were done in the FGMRI laboratory. To state the amounts of the basic nutrients and sulphur in assimilation organs of the main tree species, the threshold values, as proposed by the EP Leaf Analyses, were used, characterizing the level of insufficient and over limit nutrition – see the table.