Ozone injury responses of ponderosa and Jeffrey pine in the Sierra Nevada and San Bernardino Mountains in California

Abstract

Ozone injury was monitored on foliage of ponderosa (Pinus ponderosa Dougl. ex Laws.) and Jeffrey (Pinus jeffreyi Grev. & Balf.) pines at 11 locations in the Sierra Nevada and 1 site in the San Bernardino Mountains of southern California. Ozone injury on all age cohorts of needles on about 1,600 trees was surveyed annually from 1991 to 1994. A new method for describing ozone injury to whole tree crowns, the ozone injury index (OII), was field tested and improved. The OII ranged from 0 (no injury) to 100 (the maximum possible injury). The OII multi-year average was only 5 at Lassen Volcanic Park in rural northern California and gradually increased in a southward direction west of the Sierra Nevada crest to moderate amounts (28-41) in the Sequoia National Forest and Sequoia National Park. The OII multi-year average measured at the San Bernardino Mountain site was 46. An assessment of annual changes at the 12 individual sites indicated both increases and decreases in OII from 1991 to 1994. The two most responsive indicators of the annual increments of accumulated injury, contributing 40 percent each, were chlorotic mottle and needle fascicle retention (within remaining needle whorls). Data for these components were tested with quadratic and Weibull functions against several expressions of ozone exposure (including ozone exposure indices Sum 0, Sum 60, W126, and number of hours exceeding 80 ppb during the summer exposure periods). Sum 0 was a suitable exposure index having Weibull correlation coefficients of 0.57 with percent chlorotic mottle and 0.74 with percent fascicle retention. These results provide estimates of ozone injury responses across a range of annual accumulated ozone exposures and environmental conditions during four summers.

Parent Publication

• Proceedings of the International Symposium on Air Pollution and Climate Change Effects on Forest Ecosystems

Citation

Miller, Paul; Guthrey, Raleigh; Schilling, Susan; Carroll, John. 1998. Ozone injury responses of ponderosa and Jeffrey pine in the Sierra Nevada and San Bernardino Mountains in California. In: Bytnerowicz, Andrzej; Arbaugh, Michael J.; Schilling, Susan L., tech. coords. Proceedings of the international symposium on air pollution and climate change effects on forest ecosystems. Gen. Tech. Rep. PSW-GTR-166. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 35-42