The results indicate that it is possible to reach a good level of reproducibility in a relatively short time. However, quality assurance procedures allow to know the real status of reliability of the field data. More attention must be given to the Level II indices, to select the really useful and informative ones, and to concentrate on these the didactic efforts

The contribution summarizes outputs of annual measurements that were made in the eleven-year long period of observation (1991-2001). In this case, the liming had markedly positive effect on prosperity of spruce plantation up to now. The limed variants "surface" and "planting pit" show lower values of the total mortality than the control variant. Furthemore, the mean value of the periodic annual increment of the trees of the control variant is clearly lower than the mean values of the variant "surface" and the variant "planting pit". According to soil analyses the above described forms of liming do not seem to induce any serious negative changes within soil in this case

Wet-deposited - sulphur and nitrogen pollutants and ambient ozone are important anthropogenic factors affecting forest health. Regular assessment of chemistry of throughfall and precipitation water based on two-week sampling started in 1997. Passive samplers for detection of ozone concentration have been exposed on a network of monitoring stations during vegetation periods since 1998. In addition, in selected locations, UV absorption monitors for continuous O3 measurements were installed in 1999

The assessment of O3-like foliar symptoms is increasingly considered in monitoring programs aimed at evaluating air pollution effects on forests. The results showed considerable spatial and temporal variation of O3-like foliar symptoms: year, subplot adn the interaction between year and plot were found significant factors. Symptoms resulted lower in 2001; there were differences of foliar symptoms between different subplot and overall the variation between years are considerably different according to the plot being considered. These findings suggest that O3-like foliar symptoms recorded on a small plot selected without a formal statistical approach and with no consideration of the apparently high variability of symptoms expression risk to introduce a serious bias in the evaluation of the potential ozone impact at a given site and its trend

Soil water measurements in Swiss forest plots show a decrease of the ratio between base cations and aluminium within last 4 years. The decrease is significant in at least one soil layer in 12 of 14 plots and is strongest in areas with high acid deposition. In some of the soils the critical ratio of 1 is being reached today. The development is compared with model estimates. In Switzerland, 80% of acid deposition is made up by nitrogen compounds

A FORest Monitoring System (FORMS) has been implemented in Denmark in order to gain and deliver knowledge and information for operational and strategic decisions concerning nature and environment. FORMS integrate four national monitoring programmes. Forest condition monitoring is performed on 52 permanent plots distributed on a 16 x 16 km grid. FORMS gives a systematic and representative assessment of the resources in and development of the forests in Denmark, includes the monitoring of important processes in the forest ecosystem and follows the use of forest for recreational purposes

Pollution problems in forest ecosystems resulting from 100 year long operation of three smelter complexes in Central Spis are reviewed. Original data are presented with respect to temporal and spatial trends of nitrogen, sulphur and heavy metal pollution, and elemental composition of individual aerosols on leaf surface. Spruce stands in Central Spis are loaded by pollutants 1.7 times more than are critical values and the highest concentrations of As, Fe, Hg, and N were found in this region. Low Tatra National Park was the cleanest region where no element maxima were found

The present paper presents a list of probabilistic sampling procedures and subsequent statistical analysis, which may achieve this goal without a considerable increase of field effort

Forest ecosystems water balance research is very complicated because of forest influence upon individual components of the water balance. Global climate changes represent a real threat for forest ecosystems. In hydric area these changes concern especially thermal balance and resulting increased evapotranspiration, time and spatial distribution of precipitation

Black pine (Pinus nigra Arn.) was chosen as bioindication species for several reasons. Black pine stands are located throughout Istria, at various distances from the above mentioned power plant. Black pine does not shed needles in the autumn, thus prolonging their exposure to sulphur dioxide emissions. Also neeedles stay on branches for several years, giving us the possibility to analyse the effect on older needles