For assessment of ozone risks to forests we used ozone thresholds and air quality guidelines set by several international organizations for protection of vegetation. We also used spatial modelling for estimation of basic ozone characteristics. Calculations of models were performed in the environment of the programme Idrisi 32. The spatial coverage of ozone monitoring network in the Slovak Republic has insufficient density. Ozone data come from two sources; SHMI/EMEP database of ozone concentrations from 4 monitoring stations and ozone database of FRI from 3 monitoring stations

Foliage of three trembling aspen clones differing in O3 tolerance from Rhinelander, Kenosha and Kalamazoo were examined for 24 elements in the year 2001 and they were analyzed by INAA at reactor IBR-2, by AAS Varian 400 and by elemental analyzer LECO SC 132 and SP 228. In the fofliage of trembling aspen we found no statistically significant difference in the concentration of 22 elements except for K and Ni between clones. For the concentrations of elements between localities we found statistically significant difference for Al, Ba, Ca, Cd, Cl, Co, Cu, La, Mo, Na, Ni, Pb, Sm, Sr and Zn

Global environmental change, including increasing atmospheric CO2 and tropospheric O3 is likely to impact forest growth and wood properties. Increase in CO2 enhances photosynthesis, growth and productivity. On the contrary, O3 is detrimental to forest vitality and yield. At present reports of long-term studies on the effects of combined exposures of CO2 and O3 on stem wood chemistry of deciduous trees are lacking. The aim of this study was to investigate the effects of CO2 and O3, singly or in combination, on stem wood chemistry of four-year old saplings of trembling asspen (Populus tremuloides) clones differing in ozone tolerance, paper birch (Betula papyrifera) and sugar maple (Acer saccharum)

We aim to differentiate the various visible leaf symptoms in the field survey with microscopical methods, and to better know, how the leaf, tissue and cell response differs between injury from ozone, heavy metals (both oxidative stress) and biotic infections

The future productivity of forests will be affected by combinations of anthropogenic stresses including elevated atmospheric CO2 and O3. Because the productivity of forests, will be in part, determined by the growth of young trees, we evaluated the responses of Pinus ponderosa seedlings to ambient or elevated CO2 and/or high O3. Shoot growth and whole plant biomass were evaluated for seedlings growing under the CO2 and O3 treatments for 3 years in sun-lit mesocosms with ambient temperature and humidity. This study indicated the potential for CO2 but not O3 effects on Pinus ponderosa seedlings under realistic field conditions as used in this study

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

Many previous studies evidenced very high levels of air pollution by ozone between the North Italy (Lombardy) and the Southern Switzerland (Canton Ticino). These levels are mostly attributed to the influence of the large urbanized area of Milan and to the urban and industrial settlements in the Po Valley. Recent researches revealed the existence of spread foliar ozone-like symptoms in many native plant species, both in the Swiss and in Italian sector. Experiments carried out in open top chambers in Canton Ticino allowed us to attribute the foliar symptoms to the ambient air pollution levels

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

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