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

The average defoliation of the sites located in the western part significantly increased in 2000, probably as a result of massive needle yellowing and shedding, and the G/A bud ratio decreased for all of the sites what reflected in reduction of crown regeneration. We suppose that a further increase of crown defoliation due to exceedance of stress threshold may trigger tree defensive reactions and replacement of the loss of assimilative organs

Impacts of big polluters on adjacent ecosystems can be seen as long-term unintentional experiments. Contrary to the common guess, results of these experiments may be used to address basic ecological problems, like diversity - stability and diversity - productivity relationships, as well as evaluate general effects of disturbance on ecosystem structure and functioning. Toxicity of pollutants plays a leading role at early stages of forest decline, while transformation of forests into birch woodlands and industrial barrens is accelerated by positive feedback's acting primarily via changes in microclimate

This paper aims to integrate existing information on effects of air pollution on main forest tree species of economic importance, mainly on growth and reproduction. Gaps in knowledge and areas for future research will be identified

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

Emissions, especially of SO2 and to a certain degree of NOx have been reduced markedly in Slovakia during the 90s. Problems related to climate change and especially ozone are increasingly growing. The aim was to evaluate the long-term air pollution effect on forest ecosystems in mountain area with prevailing distribution of spruce through evaluation of spruce needle surface structure in relation to mineral nutrient status of trees. According to strong relationship between the coefficient of epicuticular wax degradation (Q) and accumulation of S and other elements it can be suggested that evaluation of needle surface structure by means of Q well reflects the surface status of needles

Instrumental neutron activation analysis (INAA) at the Joint Institute for Nuclear Research is presently being used in several projects on air pollution studies supported by the International Atomic Energy Agency and the Plenipotentiaries of the country members of JINR. They involve moss and lichen biomonitoring techniques and GIS technology for constructing geographical maps of atmospheric deposition patterns of key heavy metals and a number of additional elements. Multi-element INAA is considered to be a reference analytical technique providing most reliable results for the bulk elemental content due to the non-destructive way of sample preparation for analysis

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

Needle retention, needle density, height and radial increments were surveyed on Scots pine (Pinus sylvestris L.) in four forest regions, In the each forest region research was conducted on seven about 45-year-old pines. The Needle Trace Method (NTM) was used to determine needle retention and needle density along the main stem retrospectively for the last four decades. The NTM invented by Kurkela and Jalkanen is based on the examination of the vascular bundles connecting the needles and shoot pith. There are presented the long-term average values of needle retention in the particular forest regions, their differences. Needle retention and needle density reflected air pollution stress on the pines