Five permanent plots in pine and spruce stands were established at beginning of the 90s. The sites were situated in a gradient of air pollution level, from the south to the north of Poland. There are presented changes in SO2 and NO2 concentration in the air as well as loads of acidic compounds and the exceedance of critical loads in the period of 1993-2001. Response of the forest ecosystems was evaluated by changes in health status of trees and changes in biodiversity at forest permanent plots. The comparative study revealed an improvement in the health condition of trees and a tendency of ecosystems to regenerate due to greater than 30% decrease in emission in the last decade

Toxic effects of photochemical smog on ponderosa and Jeffrey pines in the San Bernardino Mountains were discovered in the 1950s. It was revealed that ozone is the main cause of foliar injury manifested as chlorotic mottle and premature needle senescence. Various morphological, physiological and biochemical alterations in the affected plants have been reported over a period of about 40 years of multidisciplinary research. Recently, the focus of research has shifted from studying the effects of ozone to multiple pollutant effects. Recent studies have indicated that the combination of ozone and nitrogen may alter biomass allocation in pines towards that of deciduous trees, accelerate litter accumulation and increase carbon sequestration rates in heavily polluted forests

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

Soil nitrogen (N) leaching is recognized to have negative effects on the environment. There is a lack of studies on different simultaneously occurring drivers of environmental change, including changing rainfall and N deposition, on soil N leaching. In this study, a two factorial field experiment was conducted in a Korean pine forest with the following four treatments: 30% of throughfall reduction (TR), 50 kg N ha⁻¹ yr⁻¹ of N addition (N+), throughfall reduction plus N addition (TRN+) and natural forest (CK). The zero-tension pan lysimeter method was used to assess the response of soil N leaching loss to manipulated N addition and throughfall reduction. The results showed that the soil N leaching loss in natural forest was 5.0 ± 0.4 kg N ha⁻¹yr⁻¹, of which dissolved organic nitrogen (DON) accounted for 48%. Compared to natural forest, six years of N addition (NH₄NO₃, 50 kg N ha⁻¹ year⁻¹) significantly (P < 0.05) increased soil N leaching losses by 122%, especially in the form of NO₃⁻; a 30% reduction in throughfall slightly decreased N leaching losses by 23%; in combination, N addition and throughfall reduction increased N leaching losses by 48%. There was a strong interaction between N addition and throughfall reduction, which decreased N leaching loss by approximately 2.5 kg N ha⁻¹ yr⁻¹. Our results indicated that drought would diminish the enhancing effect of N deposition on soil N leaching. These findings highlight the importance of incorporating both N deposition and precipitation and their impacts on soil N leaching into future N budget assessments of forest ecosystems under global environmental change.

We estimated the sample size (the number of samples) required to evaluate the concentration of radiocesium (¹³⁷Cs) in Japanese fir (Abies firma Sieb. & Zucc.), 5 years after the outbreak of the Fukushima Daiichi Nuclear Power Plant accident. We investigated the spatial structure of the contamination levels in this species growing in a mixed deciduous broadleaf and evergreen coniferous forest stand. We sampled 40 saplings with a tree height of 150 cm–250 cm in a Fukushima forest community. The results showed that: (1) there was no correlation between the ¹³⁷Cs concentration in needles and soil, and (2) the difference in the spatial distribution pattern of ¹³⁷Cs concentration between needles and soil suggest that the contribution of root uptake to ¹³⁷Cs in new needles of this species may be minor in the 5 years after the radionuclides were released into the atmosphere. The concentration of ¹³⁷Cs in needles showed a strong positive spatial autocorrelation in the distance class from 0 to 2.5 m, suggesting that the statistical analysis of data should consider spatial autocorrelation in the case of an assessment of the radioactive contamination of forest trees. According to our sample size analysis, a sample size of seven trees was required to determine the mean contamination level within an error in the means of no more than 10%. This required sample size may be feasible for most sites.