More Fog in the Smokies

To the Editors:

Charles Schwartz’s explanation of the fog in the Great Smokies was close but not quite right [NYR, April 15, responding to “Appalachian Spring” by V.S. Pritchett in NYR, January 21]. To be more precise, long-leaf pines and slash pines live in the flat parts of the Coastal Southeastern and Deep South states. There are few, if any, slash or longleaf pines in the Appalachian Mountains. The fog is not from turpentine from cuts in these or any other pines. The fog is generated by volatile oils (called terpenes) generated by the many hardwoods and few evergreen species in the Mountains. They release these oils whether or not they have been cut. The molecules of these terpenes form nucleii for water vapor to condense around, forming little droplets which add up to form the drifting fog banks.

Joshua Banner

Ann Arbor, Michigan