Long-term effects of ozone onFagus sylvaticaL. — An open-top chamber exposure study

✍ Scribed by Georg H. M. Krause; Friedrich-Eberhard Höckel

• Book ID: 104782410
• Publisher: Springer Netherlands
• Year: 1995
• Tongue: English
• Weight: 431 KB
• Volume: 85
• Category: Article
• ISSN: 0049-6979
• DOI: 10.1007/bf00477167

✦ Synopsis

The Landesumweltamt North-Rhine Westfalia is operating eight open-top chambers as well as six reference plots at a site on a westerly exposed slope (540 m a.s.) in the Egge mountains, 130 km northeast of the Ruhr area. Since 1991 eighteen 6 yr old beech trees (Fagus sylvatica L.) j~er plot/chamber were exposed either to ambient air (AA), non-filtered air (NF) or charcoal-filtered air. Ambient air pollutants (03. 802, NOx) as well as meteorological parameters were monitored continuously inside chambers as well as in the ambient Growth parameters (bud development, stem diameter, shoot length, shoot diameter, leaf area, leaf colouration, leaf abscission) were assessed over the years 1992 -1994.

Even in the fu'st year a marked earlier colouration of the leaves was observed in the NF (AOT 40 = 16.2 p.prn-hr) versus the CF treatment (AOT 40 = 0.2 ppm,hr) and leaf abscission was two weeks earlier on NF-trees, indicating the common ozone effect of early senescence. Effects became more pronounced with increasing time of e.xposure.

While hardly any effects on growth could be seen during the first and second year, shoot length and shoot diameter were reduced significantly by about 15 % in NF versus CF treatments in 1994. Similar effects were seen for the leaf area. No effects could be shown for bud development or stem diameter. Ozone specific symptoms were observed on individual trees in the NF and AA treatments and especially pronounced in 1994 (AOT 40 = 24.1 ppm.hr), but also to a much lesser extent in the CF-treatment. AOT40 value of 10 ppm.h, proposed as provisionalstandard for the protection of trees by UN-ECE seems to be stringent enough according to the results of this exposure study.