The Influence of Ozone on Deciduous Forest Tree Species

Wien

1972

5 Tab., 21 Lit. Ang.

Unselbständiges Werk

673

200144519

Two- to five-year-old seedlings of 21 species of deciduous trees commonly found in northeastern U. S. A. were exposed to 03 dosages of 25 pphm for 4 or 8 hr and to 10 pphm for 2, 4, 6 or 8 hr at 21° C, a relative humidity of 75%, and 1400 ft-c of light. All plants were exposed to 1 hr of darkness prior to fumigation. Symptoms developed on green ash, white ash, sweet gum, pin oalc, scarlet oak, white oak, hybrid poplar, mountain ash, sycamore, redbud, honeylocust and tulip poplar following exposure to 25 pphm for 8 hr. The most common symptoms observed were stipples of the upper leaf surface, necrotic flecks, overall leaf chlorosis, marginal leaf necrosis, overall leaf necrosis, and tissue collapse. Exposure of these species to 25 pphm O3 for 4 hr injured green ash, white ash, mountain ash, honeylocust, white oak, hybrid poplar, and tulip poplar. Exposures at 10 pphm O3 for 8 hr injured white ash, honeylocust, hybrid poplar, tulip poplar, and sycamore. Symptoms failed to develop on European white birch, gray dogwood, flowering dogwood, little-leaf linden, Norway maple, sugar maple, English oak, red oak, and shingle oak exposed to 25 pphm for 8 hr. The incidence of sensitive plants within seedling population of each species ranged from 19% to 100%; with the exception of white ash, all species were resistent during the first two weeks of growth following bud break in the spring.