© 1987 Heron Publishing—Victoria, Canada
Pollution-induced injury in North American forests: facts and suspicions
James N. Woodman
Atmospheric Impacts Research Program, School of Forest Resources, North Carolina State University, Raleigh, North Carolina
27606, USA /
Summary
Toxic gases are the only airborne chemicals that have been demonstrated to cause detrimental effects on forest trees in North
America. Ozone is the only regionally dispersed pollutant known to have injured foliage, decreased radial growth, decreased
resistance to insects and diseases, and increased mortality of sensitive tree species over a wide geographic range. All of
these effects have been observed in eastern white pine (Pinus strobus L.) throughout its natural range, in some conifers and hardwood trees in southern California, and in a few tree species in
the central Appalachian Mountains. Very little research has been done to determine effects of airborne chemicals on forests
as a whole. At present, there is no conclusive evidence that acid deposition or other regionally dispersed pollutants are
affecting the productivity of any forest in North America.
