“…This was an expected result because several investigators have reported decreased branching and leaf area under ozone treatment (Matyssek et al, 1992;Karnosky et al, 1996;Bortier et al, 1997;Oksanen and Saleem, 1999). Additionally, clone 80-known to be ozone sensitive from earlier experiments with seedlings (Pääkkönen et al, 1997)-showed less decline in leaf area.…”