Effects of Ozone on Forests

Plant expends energy to make sure the ozone does not kill cells in the mesophyll.

Symptoms may be present on the foliage. These blackberry plants near Shining Rock Wilderness had severe ozone symptoms present in mid-August 1997.

Growth and yield reductions

Cause the vegetation to be under a chronic stress where insects or diseases attack the trees. San Bernardino Mountains, October 2004

A reduction in biological diversity due to competition between species. The amount of Ponderosa and Jeffries pine have been reduced in this stand from the chronic and acute ozone exposures in the San Bernardino Mountains. Decades on ozone exposures were combined with a decade of drought and bark beetles completed the mortality. The result has increased the amount of oaks in the stand, and decreased the amount of Ponderosa pine.