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

Instrumental neutron activation analysis was used for determination of element concentration in 10 year old segments of lime wood in extremely polluted area in Central Spis. We found the highest concentrations of Al, As, Au, Br, Cl, K, Na, Rb, Sb and Sm in the oldest 80-90 year old forest. The same elements were determined in atmospheric deposition with moss bio-monitoring technique. In the area of Central Spis we found in comparison with Norwegian limit values exceeded levels for the elements as given similarly for comparison with Magnitogorsk in Ural Mountains

Forest soil condition in Slovakia harmonised with the programme ICP Forests has been monitored since 1988. There are presented some results of the first complete survey for 111 observation plots and three sampling depths (overlaying humus layer, 0-10 cm and 10-20 cm layer of mineral soil). Geological and geochemical diversity has resulted in rather differentiated forest soil condition and soil properties in Slovakia. That has strong effect on sensitivity to soil acidification as well as it brings other risks of air pollution impact

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

Ailanthus altissimia Desf. is a non-native species spread throughout the Southern Europe as invasive plant. It demonstrated to be very sensitive to ozone and ozone-polluted environment, develops brownish stipples on the upper leaf surface. In the 2001 summer 12 young plants were placed in a site near the city of Florence (Italy), where high levels of ozone were experienced. Six of them were regularly watered and six were watered only when the wilting of their leaves was evident. Regular assessments were done during the experiment. They concerned growth, production of new leaves, dead and shedding of old leaves, visible symptoms of damage, stomatal conductance and CO2 uptake, chlorophyll fluorescence. The results suggest that the sensitivity to ozone of watered plants is connected to their higher growth ratio and stomatal conductance. Ozone plays a more important role than drought in producing foliar stress conditions

Two holm oak (Quercus ilex L.) sites in Tuscany, Central Italy, were studied in July 2000. Leaf morphological characteristics (area, dry weight, specific dry weight, water content, epicuticular wax amount, stomatal density) and leaf fluorescence were measured. Ozone flux into the leaves was calculated on a stomatal conductance basis. Among the measured parameters, only stomatal density and wax amount significantly differed between the sites. This response might indicate an adaptation to air pollutants, of which tropospheric ozone might be of the greatest importance

The results showed that ozone specific symptoms can be detected in the needles of mature spruces in the southern Sweden with AOT40 considerably lower than the present critical level of 10 000 nl 1sup-1. The results could be expressed as an index per tree and needle generations, but also as a single value for forest stand allowing statistical tests. The results from this study support the general hypothesis and results from exposure and field studies that low nutrient concentrations or nutrient deficiency modifies the ozone response in plants. The results also show that together with low nutrition status ozone may affect the hardiness status of the needles

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

Selected parameters of the nutrients cycling process for forest ecosystem were investigated in period 1989-2000 at Prednji Vrh in the area affected by the Sostanj thermal power station. In the year 1995 desulphurization of exhaust gases from the TPP Sostanj caused considerable reduction of SO2 emission. We could not find serious tree-ring width decline in spruce. In the year 1956 and 1978 tree-ring widths rapidly declined. In the year 1995 slight icrement recovery could be observed. One probably climatically (drought) induced pointer year (1992) occurred

Small attention has been still addressed to the study of ozone effects on seminatural vegetation. Following this direction we selected an ozone heavily exposed area in Northern Italy, where the development of visible injuries on leaves of common pasture herbs were observed. The selected area, an alpine pasture located at Moggio belongs to the Level II permanent monitoring network of the ICP-Forest program. The ozone exposure mapping exercise made on the whole regional domain estimated for this area an AOT40f of 32000 ppb.h as 1999 and 2000 years average