The aim of the experiment was to find out the influence of various thinning regimes on health condition of young stands of Norway spruce under the stress of air pollution. The experiment is based on comparative method. The series consists of three comparative plots with different thinning regimes. The comparative plot 1 is a control plot without thinning. The program with heavy thinning from below has been tested on the plot 2 and the program based on one very heavy thinning in the young age and longer periods was applied in the stands of plots 3. Health condition of experimental stands was assessed on defoliation in 1982, 1981 and since 1987 annually on both series

Investigation of air pollution impact on tree condition indicates the greatest correlation between pine defoliation and SO2, SO4 and NH4 concentration in the air, NH4 load with precipitation and its pH in the eastern part of Lithuania. In the southern part significant correlation was found between defoliation and SO4 concentration in the air and SO4, NH4 load with precipitation and its pH. No significant correlation was found in the western region of the country, which includes seaside part. Tree age and tree development classes have an essential effect on the correlation significance

Stimulation of photosynthesis by elevated CO2 has been consistently found for aspen but not for maple. Similar responses have been shown for growth. In contrast, O3 causes decreased levels of photosynthesis and growth in aspen but does not appear to impact sugar maple significantly. When the pollutants co-occur, CO2 induced enhancements in photosynthesis and growth are moderated so that trees in CO2 and O3 treatments respond similarly to those in control rings. In this presentation, we will provide a physiological interpretation of our results in modelling growth response under future atmospheric conditions

Interactions between atmospheric deposition and nutrient status or soil condition were studied using correlation analysis of the principal factors values for the year 1989. In case of both species, especially sulphur and calcium (factor 1) input is related to high foliar content of sulphur and calcium. The same influence can be detected for nitrogen (factor 3). Nitrogen inputs on Scots pine stands influenced the magnesium sufficient in a negative way

Results obtained by crown status estimation and branch structure transformation assessment methods are also applicable at forest stand level. By means of these methods we can reconstruct a scheme of probable stress response history for individual trees with possibility to distinguish three different types of stress response behaviour. The goal of our study was to describe a stress response history of single trees and corresponding forest stands, diverse in different level of multiple stress impact, and to localize investigated trees in the stress response scheme

Ozone is a well-known phytotoxic agent causing damage to vegetation in parts of North America and Europe. Transboundary or long-range transport of ozone from Western Europe and the generation of ozone from local and regional precursors results in increasing ozone concentrations in Central and Eastern Europe, including the Carpathian Mountaians. Other air pollutants such as sulphur dioxide, nitrogen oxides, ammonia and heavy metals may also affect the health of Carpathian forests. During the 2000-2002 summer seasons, concentrations of ozone, sulphur dioxide, nitrogen oxides and ammonia were monitored with passive samplers. Results of those measurements will be used for development of GIS models of spatial and temporal distribution of air pollutants

Two field exercises for the assessment of foliar visible ozone symptoms were performed during the "2nd UN/ECE ICP-Forests Intercalibration Course on the Assessment of Ozone Injury on European tree Species" organised by the WSL in collaboration with the University of Florence, Linnaea ambiente, and the PSU. The exercises were conducted at the Lattecaldo OTC research facility in Southern Switzerland and on the Moggio Level II plot in Northern Italy from 22-24 August 2001. 48 participants represented 21 countries. There are given objectives and results and conclusions from both sites

Scientific concern over air pollution impacts on forest health and ecosystem function have evolved from local (point-source), to regional (area source) and ultimately to the global scale (increasing atmospheric CO2). All three scales of investigation remain relevant to increasing our understanding of how air pollution affects forests. Presently, linking air pollution with forest health status through routine monitoring network data remains problematic. In this paper we present a brief overview of air pollutant trends, together with recent European forest condition monitoring and FACE experimental case-study evidence to illustrate the need for multiple-level investigation of air pollutant-forest interactions

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