>Tha Associated Press reported today that almost one in five trees in >Europe shows clear signs of damage from pollution, losing at least a >quarter of their foliage. The report was generated by the European Union >and the UN. The above information, provided to the Net by Bret Diamond, cannot go unanswered. I have not seen the AP report. If the message from Bret is true, then AP Press got it wrong. The report published by the EU and UN, parts of which I wrote on behalf of Switzerland, and all of which I reviewed, did NOT say that "almost one if five trees show clear signs of damage from pollution". The report says that 25.3% of the 117 035 trees assessed in the sample are classed as having more than 25% defoliation. Drought and heat are considered to have a high impact on defoliation, with pest infestation, silvicultural operations, game and grazing also having an effect. Direct damage by pollution was identified on 243 trees, i.e. 0.228% of the trees. Indirect damage by pollution may be involved in some of the defoliation, but this cannot be assessed by the type of assessment reported in the UN/EC publication. Regarding Central Europe, the report states that air pollution may be predispose trees to decline, although this is not backed up by any evidence. It is worth citing the report in detail: "Definite causes for the deterioration of forest condition are difficult to identify. National surveys offer a variety of explanations for the forest condition development in the respective countries. Adverse weather conditions play a major role as stressing factor. Frost periods have an important impact on the forest condition in the succeeding vegetation period. Also drought avdersely impairs the vitality of trees. In consequence, trees might be more susceptible for insect or fungi attacks. The susceptibility of trees towards pest infestation may be intensified by air pollution. Almost one half of the countries participating in the transnational survey of forest condition mentioned air pollution as potentially affecting trees. These countries are mainly situated in central and south-eastern Europe, where the most severe deterioration of forest condition occurs". John Innes Dr John L. Innes Swiss Federal Institute for Forest, Snow and Landscape Research Zuercherstrasse 111, CH-8903 Birmensdorf Switzerland Tel: (+41) 1 739 2216 FAX: (+41) 1 739 2215 email: john.innes@wsl.ch
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