Columbia subject headings:
Forest ecology--Canada, Eastern.
Forest ecology--East (U.S.)
Forest plants--Effect of air pollution on--Canada, Eastern.
Forest plants--Effect of air pollution on--East (U.S.)
Trees--Effect of air pollution on--Canada, Eastern.
Trees--Effect of air pollution on--East (U.S.)
Trees--Wounds and injuries--Canada, Eastern.
Trees--Wounds and injuries--East (U.S.)
Harvard subject headings:
Acid deposition--Environmental aspects--Northeastern States.
Air--Pollution--Northeastern States.
Forest ecology--Canada, Eastern.
Forest ecology--East (U.S.)
Forest plants--Effect of air pollution on--Canada, Eastern.
Forest plants--Effect of air pollution on--East (U.S.)
Forests and forestry--Northeastern States
Ozone--Environmental aspects--Northeastern States.
Trees--Effect of air pollution on--Canada, Eastern.
Trees--Effect of air pollution on--East (U.S.)
Trees--Wounds and injuries--Canada, Eastern.
Trees--Wounds and injuries--East (U.S.)
Princeton subject headings: