The present report documents the forest condition in Europe, based on transnational and national surveys by the United Nations Economic Commission for Europe (UN/ECE) and the European Commission (EC). 30 European countries submitted national reports. These represent 25 170 plots with 634 993 sample trees, covering about 151 million hectares of forest. 30 countries also participated in the transnational survey on the basis of the 16 x 16 km grid. For the transnational forest condition assessment, 5 388 plots with 117 035 trees were investigated. The submitted reports give evidence that forest damage still is a serious problem in Europe. Although improvements of forest condition were reported from certain locations, the overall forest damage seems to increase on the European level. Of the 117 035 trees (transnational sample) assessed in 1995, defoliation by more than 25 % was found in 25.3 % of the total sample. Discolouration by more than 10 % of leaves was observed in 10.2 % of the total sample trees. The share of damaged Common Sample Trees (CSTs) of 1994-1995 increased from 25.2 % to 26.8 %. Of the individual regions, the largest increase (from 15.3 % to 19.4 %) occurred in the Mediterranean (lower) and in the Mediterranean (higher) regions (from 20.8 % to 25.1 %), particularly in Quercus suber, Quercus ilex and Eucalyptus spp., and was mainly attributed to heat and drought. However, the latter species showed the lowest damage in the Mediterranean regions. The Boreal (temperate) region, in contrast, showed a distinct improvement of forest condition (21.3 % to 17.6 %), where especially the improvement of Pinus sylvestris contributed to the better health condition. The changes in forest condition in the Sub-Atlantic, in the Mountainous (north) and in the Atlantic (south) regions did not prove statistically significant. Deterioration in the Boreal, Atlantic (north) and Mountainous (south) regions was mainly influenced by the abundant occurrence of severely damaged trees (e.g. decidous Quercus spp., Fagus sylvatica in central Europe). In addition to adverse weather conditions air pollution also was regarded as deteriorating the forest condition in some regions. In the sub-sample of the common trees of the surveys from 1988 to 1995, the development of the defoliation of 12 species was analyzed. The crown condition of almost all tree species deteriorated. Mainly drought and subsequent insect attacks, but also air pollution were considered as important factors worsening the condition of the tree species. For Picea abies and Pinus sylvestris, however decreasing air pollution as well as better weather conditions than in previous years were discussed as positively affecting the tree species in the respective national reports. The most severe deterioration were observed in the main damage areas of Germany, the Czech Republic, Poland and the Slovak Republic in Fagus sylvatica, Quercus robur, Quercus petraea and Abies alba. Highest increases in defoliation were observed in the Mountainous (south) for Fagus sylvatica and Quercus petraea. In the Sub-Atlantic seriously impaired tree species were Quercus robur and Abies alba. The least affected tree species with respect to long term forest condition were Pinus sylvestris and Pinus pinaster, the latter one confined to areas under warmer climatic conditions. The national reports referred to various causes as responsible for deteriorating forest condition. Drought and heat had a particularly high impact. Pest infestation, action of man, game and grazing also negatively impaired the health status of the assessed forests, as was stated in both transnational and national surveys. The direct and indirect effects of air pollution are considered to be the cause of forest decline in some areas, particularly in central Europe. However, only in a few cases has air pollution been identified as a cause of damage. Other sources of information, including the national reports submitted by individual countries, suggest that air pollution may predispose trees to decline over much wider areas, but the extent of these effects remains uncertain. Level II and III investigations are being designed to help resolve this. In addition to the already running forest condition survey on Level I, which is referred to in the above paragraphs, soil and foliar analysis extend the Level I survey. Indirect air pollution effects on forest condition are assessed by means of the forest soil condition survey and chemical analysis of leaves and needles. While sulphur deposition has been drastically reduced in comparison with the seventies, nitrogen deposition from different sources is still high negatively impairing soil chemistry and foliar nutrient status in some areas. The forest soil condition survey and the foliar analyses may help to reveal the impact of air pollution on these parameters. Also presented in this report is the design for the intensive monitoring (Level II). On 770 permanent plots scattered through Europe, different parameters are monitored on the long term scale. All EU-Memver States and 11 additional countries participate in the Level II survey. 440 plots are chosen in the EU, and 330 plots are to be assessed in non-EU countries. Crown condition, soil and foliar analyses and increment studies are carried out on all plots. Atmospheric deposition shall be monitored on 65 % of the plots in EU-countries, and on 81 % of the plots in the other countries. On many plots additional studies, such as meteorology and phytopathology, are performed. The general plot data have been recorded and submitted from most of the participating countries. Among the most abundant tree species are two conifers (Pinus sylvestris and Picea abies) and three broadleaved trees (Fagus sylvatica, Quercus petraea and Quercus robur). Age distribution shows that only a small number of the plots is younger than 20 years. The majority of the plots is located in 41 to 60 years old forest stands. Most of the plots lie within a distance of about 10 km to a meteorological monitoring station or closer.
