The Hungarian ILTER Network consists of three sites representing the characteristic biomes in the country: lake Balaton ILTER site, Sikofut oak forest ILTER site, and the Kiskun sand forest-steppe ILTER site. Hungarian ecologists have developed broad multidisciplinary research projects, which can meet both the requirements of international research standards and the domestic needs of nature conservation and environment protection. Hungarian policy and decision makers have also recognised the importance of long-term ecological research. As a consequence different grants such as Hungarian R + D "Szechenyi", EU FWS Projects, OTKA and OTKA-NSF Projects, Joint grant of Ministry of Environment and the Hungarian Academy of Sciences were awarded in the last 2-3 years, what could create the basis of national and international research cooperations of Hungarian ILTER sites

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

45 sites were selected and sampled on the transects and according to the first results of the spatial analysis, 15 more sites were added where useful for the optimal interpolation. Topsoils were sampled including both the soil organic horizons and the more superficial mineral horizon, frequently E, if reached. The depth of the organic horizons, the grass cover, ranked by its hydrophilic character, related to the incipient hydromorphy visible where Norway spruce is more declining, and the Norway spruce health status were systematically recorded

Coastal forest decline due to seasprays has been reported from all continents, both on broadleaves and conifers. The main cause has been identified in the presence of surfactants. Sea winds transport these substances to the leaves, where they are absorbed via cuticula and stomata producing indirect and also direct damage. The scope of this work is the macroscopic and microscopic assessment of the long term effects of polluted seasprays on Aleppo pines in natural conditions from the Saler coastline (Eastern Spain) inwards. Surfactants may be involved in the damage to Aleppo pine in El Saler as more severe episodes of damage have been observed in the last decade

Impacts of big polluters on adjacent ecosystems can be seen as long-term unintentional experiments. Contrary to the common guess, results of these experiments may be used to address basic ecological problems, like diversity - stability and diversity - productivity relationships, as well as evaluate general effects of disturbance on ecosystem structure and functioning. Toxicity of pollutants plays a leading role at early stages of forest decline, while transformation of forests into birch woodlands and industrial barrens is accelerated by positive feedback's acting primarily via changes in microclimate

This paper aims to integrate existing information on effects of air pollution on main forest tree species of economic importance, mainly on growth and reproduction. Gaps in knowledge and areas for future research will be identified

Presented paper based on long-term and systematic research of the negative effect of pollutants and of the content of the elements in particular parts of forest environment (the years 1965/2002) proves of the importance, need and justificatin of the research on given subject. Knowing the elemental composition of pollutants as to its quality and quantity is basic precondition with diagnosing the effect of polluted air on forest environment. For the needs of practice three main pollution deposition types (acid, alkaline and ammonia) and 8 subtypes were established. They represent changes of forest ecosystems caused by different substances from pollutants

The aim of the experiment was to find out the influence of various thinning regimes on health condition of young stands of Norway spruce under the stress of air pollution. The experiment is based on comparative method. The series consists of three comparative plots with different thinning regimes. The comparative plot 1 is a control plot without thinning. The program with heavy thinning from below has been tested on the plot 2 and the program based on one very heavy thinning in the young age and longer periods was applied in the stands of plots 3. Health condition of experimental stands was assessed on defoliation in 1982, 1981 and since 1987 annually on both series

Results of the statistical tests showed the spectral disparity of the production part and highly damaged juvenile part of the spruce crown. A spectral difference of the juvenile and production crown part at early stress could not be shown. A low multiple stress impact was assessed for 75 randomly selected Norway spruce trees of the first AISA image. In case of the second AISA image occurrence of Cu-Zn sulphide mine partly influenced the crown status of the neighbouring spruce ecosystems

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