Novak K (2002) Ozone air pollution and foliar injury development on native plants of Switzerland. Masters of Science Thesis. Pennsylvania State University, University Park, PA, USA, .


ozone, above-ground part of trees, Methods: open-top chamber, open-top chamber


Southern Switzerland experiences some of the highest concentrations of ozone in Europe. Previous surveys in Canton Ticino have found foliar symptoms similar to those induced by ozone on various native tree, shrub, and herbaceous species. The objectives of this study were to assess the foliar sensitivity of 12 native tree, shrub, and herbaceous species to ozone in southern Switzerland and to examine the seasonal cumulative ozone exposures required to induce visible foliar injury on those species. The study was conducted from the beginning of May through the end of August during 2000 and 2001 using an open-top chamber research facility located within the Vivaio Lattecaldo Cantonal Forest Nursery in Canton Ticino, Switzerland. The site was located approximately 600m asl in the sub-alpine region of southern Switzerland. The current study consisted of 3 treatments with four replications (12 plots). Activated charcoal filters were used in the filtered air chambers (F), reducing ambient ozone concentrations by approximately 50%. The non-filtered air chambers (NF) received approximately 91% ambient ozone concentrations and were utilized to test for chamber effects. Open plots (Amb) were not enclosed and were exposed to 100% ambient air. Plants were examined daily and dates of initial foliar injury were recorded in order to determine the cumulative AOT40 ppb.h ozone exposure required to cause visible foliar injury. The current critical level to protect forest vegetation is expressed as AOT40 10ppm.h (the amount of ozone accumulated over a threshold of 40ppb) during daylight hours over a six-month growing season. Plant responses to ozone varied significantly among species. The results from this study confirmed that 11 out of 12 plant species investigated exhibited visible foliar injury induced by ambient ozone exposures. The symptomatic species (from most to least sensitive) were Viburnum lantana, Populus nigra, Salix alba, Crataegus monogyna, Viburnum opulus, Tilia platyphyllos, Cornus alba, Prunus avium, Fraxinus excelsior, Ribes alpinum, and Tilia cordata with Clematis spp. not showing any foliar injury induced by ozone exposure. Of the 11 symptomatic species, 5 showed injury below the critical level in the 2001 season. The presence of ozone injury on a variety of European plants species below the current critical level suggests that the standard may not be protective of all plant species.

LWF Classification

Network: Experimental, LWF, Sites: Lattecaldo, Category: non-reviewed,