Red alder

Ozone injury usually appears as black or purple spots (stipple), yellow or white bleached spots (chlorotic mottle, needle tip burn), or leaf browning (necrosis). Ozone may also cause premature leaf drop (senescence).

Healthy Red alder Courtesy, Oregon State University Department of Horticulture

Ozone Injury to Red alder Leaf Courtesy, USDA Ozone Biomonitoring Program

Ozone Injury to Red alder Leaves Courtesy, USDA Ozone Biomonitoring Program

Close-up View of Ozone Injury to Red alder Leaf Courtesy, USDA Ozone Biomonitoring Program