Observation and confirmation of foliar ozone symptoms of native plant species of Switzerland and southern Spain

Tropospheric ozone is considered as the major pollutant of concern to the h ealth and productivity of forests in the eastern United States and has more recently become of increasing concern within the forests of southern Europ e. Recent observations have clearly demonstrated foliar injury symptoms to be occurring on many tree and native plant species within remote forested a reas. Several plant genera (and a few species within genera) found in both the forests of Switzerland and the southern coastal region of Spain exhibit field symptoms typical of ambient ozone exposures. Ozone exposures for man y species have been conducted under controlled CSTR conditions and within o pen-top chambers within the study areas. Results have confirmed that the O- 3-like foliar symptoms as observed under natural forest and open grown cond itions for many native tree, shrub, and herbaceous species in Spain and Swi tzerland are caused by exposures to ambient O-3.