Symptoms Caused by Photochemical Air Pollution Injuries to Forest Trees

Wien

1971

S. 71-82

2 Tab., 27 Lit. Ang.

Unselbständiges Werk

200144167

Unexplained needle injuries on eastern white pine and ponderosa pine trees in the forest have been intensively investigated in recent years. Artificial ozone fumigation experiments conducted in the laboratory to duplicate symptoms of injury observed in pine trees were started in Canada in 1959 and in the United States in 1961. Many needle disorders were found to the attributable to atmospheric oxidants of which ozone forms the greatest part. Although symptoms of oxidant injuries on forest trees are specific, confusion many arise in differentlating similar symptoms caused by other agents. For example, semimaturetissue needle blight (SNB) of eastern white pine, a physiogenic disease, prouces symptoms closely resembling a portion of those caused by photochemical air pollutants. This paper describes and compares the symptomatology of ozone injury, chlorotic dwarf, and SNB of eastern white pine, and chlorotic decline of ponderosa pine. The concentrations of atmospheric oxidatns and the exposure periods required to cause injury on forest trees are outlined. The interaction of atmospheric oxidants and sulphur dioxide in causing injury to eastern white pine is also discussed. Additional research is required to explore the action of mixtures of air pollutants in causing injury to forest trees.