Major part of implemented measures was aimed at early artificial forest regeneration and securing plantations, or protection of young forest stands against damage by bark beetles. Only exceptionally there were proposed measures with the aim to increase vitality, stability and improvement of the structure of forest stands by their tending. It was worked out a draft of procedures for forest managers to help them in deciding at which stocking it is necessary to reforest reduced or actual clearings, whether to fell down open stands or to leave them regarding their age, state and expected further development

Significant correlations (p0.05) were found between the concentration of elements in the c needles and the distance of the sites from nitrogen ferilizer factory (NFF): the amounts of C, K, Mg, Zn, and Rb in the c+1 needles were increasing, whereas concentrations of N, P, Al, Mn, Cu, Ni, Sr and Cd were decreasing alongside the transect from NFF. Statistical analyses performed on logarithms and estimation of components of variance by maximum likelihood has shown that the age of the needles and the sites were the most important, while year of sampling was much smaller source of variance. Only a few significant differences were found comparing the amount of elements in Scots pine needles collected in four-year space

Several investigations about air pollution impact on forests have been carried out in Slovenia during last thirty years, mainly using the Norway spruce (Picea abies [L.] Karst.) as the main bioindication species, but there is a lack of information about common beach (Fagus sylvatica L.) condition, the most important forest tree species in Slovenia and in Zasavje area. The assessment of air pollution effect on beech based on stress physiological indicators of foliage, macronutrients level in beech leaves and by assessment of crown defoliation was carried out altogether with necessary soils analyses of the selected beech stands. On the basis of all parameters it can be concluded that the worst condition of beech trees in Zasavje is due to high level of air pollution, mainly by sulphur dioxide and not by deficiency of macronutrients or unfavourable state of soils

Under elevated CO2 photosynthesis was 15-50% higher than in chamber controls depending on the weather conditions of the growing seasons. When measured at 360 ppm CO2 both elevated CO2 and elevated CO2 + O3 treatments decreased net photosynthesis, stomatal conductance and also transpiration, indicating downregulation of photosynthesis at elevated CO2

Results of the statistical tests showed the spectral disparity of the production part and highly damaged juvenile part of the spruce crown. A spectral difference of the juvenile and production crown part at early stress could not be shown. A low multiple stress impact was assessed for 75 randomly selected Norway spruce trees of the first AISA image. In case of the second AISA image occurrence of Cu-Zn sulphide mine partly influenced the crown status of the neighbouring spruce ecosystems

Ectomycorrhizal types were quantified in soil cores taken from 0-5 cm horizon. Nine ectomycorrhizal types were distinguished on roots of pines grown close to the copper smelter, 17 on trees grown in vicinity of aluminium smelter versus 25 found on trees grown near phosphate fertilizer plant and from control trees. Molecular studies were performed to give a greater resolution of how emission from different sources influenced mycorrhizal fungal community of Scots pine

Five permanent plots in pine and spruce stands were established at beginning of the 90s. The sites were situated in a gradient of air pollution level, from the south to the north of Poland. There are presented changes in SO2 and NO2 concentration in the air as well as loads of acidic compounds and the exceedance of critical loads in the period of 1993-2001. Response of the forest ecosystems was evaluated by changes in health status of trees and changes in biodiversity at forest permanent plots. The comparative study revealed an improvement in the health condition of trees and a tendency of ecosystems to regenerate due to greater than 30% decrease in emission in the last decade

The need to assess the role of terrestrial ecosystems in the global C cycle and the potential change of this role as the atmospheric concentration of CO2 increases attracted considerable scientific attention over the recent decade. In order to assess ecosystem responses as a whole and to evaluate the potential role of forests and tree communities as a carbon sinks, the below-ground response to increasing levels of CO2 must be addressed

Increased ozone sensitivity of larger soil-growing trees with growth in the multi-year exposure was a result of several interactive senescence-related physiological factors: lower net photosynthesis to stomatal conductance ratio at the end of the growing season promoted high ozone uptake and low photosynthetic carbon gain, leading to onset of visible injuries and impaired bud formation. This was expected to affect negatively the early growth of the next year foliage, This clone showed a major change in allocation pattern during the early ontogeny at the expense of foliage growth towards the stem height increase

The attention was focused on the diameter increment of beech timber forest growing on the partial plots with various stand density. The individual parts of the originally homogenous stand, were subjected to regeneration cutting of various intensity resulting in several partial plots. On the different partial plots we found different proportions of trees belonging to the individual diameter classes. We also found that the differences between the individual plots were statistically very significant. Beech is a tree species which is capable to continue creating considerable light increments even long after the stand opening