Ponderosa pine

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 Ponderosa pine Tree Courtesy, USDA PLANTS Database

Healthy Ponderosa pine Cone Courtesy, USDA PLANTS Database

Healthy Ponderosa pine Needles Courtesy, USDA PLANTS Database

Ozone Injury to Ponderosa pine Needles, Courtesy, USDA PLANTS Database

Ozone Injury to Ponderosa pine Needles Courtesy, USDA Ozone Biomonitoring Program

Ozone Injury to Ponderosa pine Tree Courtesy, USDA Ozone Biomonitoring Program