Observations of ozone-induced foliar injury on black cherry (Prunus serotina, var. capuli) within the Desierto de Los Leones National Park, Mexico City

A survey for ozone-induced foliar injury of black cherry was conducted in mid-June 1995 within the Desierto de Los Leones National Park located southwest of Mexico City. Evaluations of the upper and lower tree crowns of 18 trees revealed evidence of significant upper surface stipple, leaf reddening and premature senescence on 72% of the trees. A general survey of an additional 169 trees disclosed that 41% exhibited similar symptoms. A gradient of increasing symptoms with increasing elevation was also evident. For the most part, asymptomatic trees were observed to be situated within well-shaded coves at the lower elevations with very few symptomatic trees present in these areas.