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

Remarkable differences were found in soil development on three sites. At Modru Dul (the least damaged site) Sopdosols and Inceptisols were found, in Alzbetinska (moderately damaged) Entisols are common, while in Mumlavksa hora (highly damaged) the representative soils are several kind of Podzols, with variable degree of drainage restriction and organic soils. The heavy metal content is always rather low and the vertical distribution does not indicate any appreciable contribution of atmospheric contamination

The magnesite plants Jelsava and Lubenik emitted in the 80s 30 000 tons of magnesite dust and heavy metals and 4000 tons of SO2 per year, what caused an extreme damage to the vegetation in the area around of about 500 km2. For the determination of 3 zones of endangerment we used pollution index values. In each pollution zone we demarcated experimental plots and carried out soil analyses. Forest stands polluted by magnesite dust belong to alkaline air pollution type

The alkalinization has a positive influence on soil microflora abundance. The number of ammonifiers nearby the plant is greater by 2-4 times than in relatively unpolluted soils of the same type, while the amount of denitrifiers and anaerobic nitrogen-fixing microorganisms even by 20-50 times. Alkalinization has induced biological soil activity. The data obtained are compared with the data of analogous studies conducted on forest ecosystems affected by acidifying pollutants

Problems of the environment pollution in Ziarska basin are connected with the operation of Aluminium plant from 1953. After replacement of old production technology by a a new one by Norwegian company Hydro Aluminium emission of dust of Al2O3 dropped from 766 tons per year to 243 tons per year, emission of fluorides dropped from 847 to per year to 65.9 tons per year and of SO2 have increased from 716 to 974 tons per year. The mentioned reduction of emission reflected markedly in a great reduction of vegetation loading by fluorine. In the year 2001 we found statistically sifnificant difference for total Ksupz (coefficient of loading) in coniferous and broadleaved tree species in A polution zone in comparison with the zone B, C and D

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

Both CO2 and ozone increased the diseased leaf area of clone V5952 in Exp. 1 in the year 2000. The size of spots increased most under ozone fumigation, and the number of spots under ozone and CO2 + O3 fumigations. In clone K1659 all fumigation treatments decreased or had no effect on the DLA, or the number and size of the leaf spots. Also the number of fallen leaves under fumigation treatments was higher in clone V5952 than in clone K1659. Analysis of the year 2001 monitoring results is currently going on

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

We studied elevated CO2 and ozone effects in single and in combination on crown structure of two Betula pendula clones. Shoot ramification, shoot length, number of metamers, leaves and buds were measured at four heights in every tree. Chamber effect was substantial on sylleptic branching and on shoot length and ramification. However these responses differed between the clones. Ozone treatment affected shoot length and caused slight decrease in shoot ramification. Elevated CO2 affected appearance of long shoots in complex manner, but in lower crown positions CO2 caused increased number of long shoots in both clones

The results showed that the hydrogen load had a very significant variation between the two monitoring years. In 1999-00 water year, hydrogen load was 4.72 kmol/ha, while in 2000-01 it was 1.70 kmol/ha. Although the observed pH values of rainwater never got over 7.0, high values around 6.0 were determined in summer moonths. The average equivalent concentrations of measured ions were calculated and an equilibrium between anions and cations was found