The biological effects of both elevated CO2 and N deposition on model ecosystem were investigated in the Birmensdorf open-top chamber facility. Each of the 16 chambers was divided into two compartments with a ground area of 3 msub2 and filled with natural unfertilized forest soils from two sites (one acidic, the other calcareous). Elevated CO2 significantly increased O and Zn concentrations in beech leaves and those of Zn in spruce needles on the calcareous soils. Enhanced N deposition also led to a dilution of nutrients and increased N contents

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

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

Several investigations about air pollution impact on forests have been carried out in Slovenia during last thirty years, mainly using the Norway spruce (Picea abies [L.] Karst.) as the main bioindication species, but there is a lack of information about common beach (Fagus sylvatica L.) condition, the most important forest tree species in Slovenia and in Zasavje area. The assessment of air pollution effect on beech based on stress physiological indicators of foliage, macronutrients level in beech leaves and by assessment of crown defoliation was carried out altogether with necessary soils analyses of the selected beech stands. On the basis of all parameters it can be concluded that the worst condition of beech trees in Zasavje is due to high level of air pollution, mainly by sulphur dioxide and not by deficiency of macronutrients or unfavourable state of soils

Rigorous studies on long-term changes of heavy metal distribution in forest soils since the implementation of emission controls are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area) and foliar chemistry from three decades ago. It was hypothesized that declining deposition of heavy metals is reflected in soil and foliar total contents of Pb, Cu, Zn, Ni, Mn and Fe. Mean soil contents of Pb in the stemflow area declined at the highest rate from 223 to 50 mg kg−1 within the last three decades. Soil contents of Pb and Ni decreased significantly both in the stemflow area and the between trees area down to 80–90 cm soil depth from 1984 to 2012. Top soil (0–5 cm) accumulation and simultaneous loss in the lower soil over time for the plant micro nutrients Cu and Zn are suggested to be caused by plant uptake from deep horizons. Reduced soil leaching, due to a mean soil pH (H2O) increase from 4.3 to 4.9, and increased plant cycling are put forward to explain the significant increase of total Mn contents in the infiltration zone of beech stemflow. Top soil Pb contents in the stemflow area presently exceed the critical value at which toxicity symptoms may occur at numerous sites. Mean foliar contents of all six studied heavy metals decreased within the last three decades, but plant supply with the micro nutrients Cu, Zn, Mn and Fe is still in the optimum range for beech trees. It is concluded that heavy metal pollution is not critical for the studied beech stands any longer. Microsites, affected by beech stemflow, are very useful for studying the legacy of high atmospheric heavy metal deposition.

Stomata tend to narrow under ozone (O3) impact, leading to limitation of stomatal O3 influx. Here, we review stomatal response under recently conducted free-air O3 exposure experiments on two species of the same tree genus: Fagus sylvatica at Kranzberg Forest (Germany) and F. crenata at Sapporo Experimental Forest (Japan). Both beeches exhibited reduction in stomatal conductance (gs) by 10–20% under experimentally enhanced O3 regimes throughout the summer relative to ambient-air controls. Stomatal narrowing occurred, in early summer, in the absence of reduced carboxylation capacity of Rubisco, although photosynthetic net CO2 uptake rate temporarily reflected restriction to some minor extent. Observed stomatal narrowing was, however, diminished in autumn, suggesting gradual loss of stomatal regulation by O3. Monotonic decline in gs with cumulative O3 exposure or flux in current modeling concepts appear to be unrealistic in beech.

In 2006, a controlled infection study was performed in the ‘Kranzberger Forst’ to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2× ozone) and three control trees (ambient = 1× ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection. Chronic sublethal ozone exposure reduces both natural and artificial infestation of beech leaves by the endophytic fungus Apiognomonia errabunda.

Here we synthesize key findings from a series of experiments to gain new insight on inter-plant competition between juvenile beech (Fagus sylvatica) and spruce (Picea abies) under the influence of increased O3 and CO2 concentrations. Competitiveness of plants was quantified and mechanistically interpreted as space-related resource investments and gains. Stable isotopes were addressed as temporal integrators of plant performance, such as photosynthesis and its relation to water use and nitrogen uptake. In the weaker competitor, beech, efficiency in space-related aboveground resource investment was decreased in competition with spruce and positively related to Δ13C, as well as stomatal conductance, but negatively related to δ18O. Likewise, our synthesis revealed that strong belowground competition for water in spruce was paralleled in this species by high N assimilation capacity. We suggest combining the time-integrative potential of stable isotopes with space-related investigations of competitiveness to accomplish mechanistic understanding of plant competition for resources. Combination of space-related concepts of competitiveness with stable isotopes has potential to clarify mechanisms of competition.