Die Symptomatologie forstlicher Rauchschäden bei Koniferen

Wien

1971

47 Lit. Ang.

Unselbständiges Werk

673

200144148

Due to their minor content of storage tissue and, therefore, reserve materials, their low capability for regeneration and the long life of their assimilation organs, conifers are amongst the most sensitive groups in respect to the impact of gaseous pollutants. Differences in the sensitivity of whole plants and assimilation organs necessitate a separate discussion of symptoms in needles and trees. Comparison of chronic and acute injuries in needles caused by sulfur dioxide, fluorine compounds and nitrio oxides demonstrates that differences are not pronounced enough to be of value in differential diagnosis. Quite generally, acute injuries are characterized by tip necroses, which affect a different length of the terminal needle parts depending on the concentration of the pollutant. Effects on cell physiology are discussed in connectlon with the description of microscopic symptoms, Needle necroses as well as alterations of tree appearance are not specific for pollution effects, a number of other factors having been found to produce similar symptoms. So, symptoms can be regarded as characteristic, but not sufficiently distinct for an unequivocal diagnosis. An evaluation of symptoms proves very useful for pollution studies, however, in connection with other methods (e.g. chemical analysis of air or plant samples).