Abstract
Sprouts from the root systems of American chestnut (C. dentata (Marsh.) Borkh.) have been increasing in numbers and size in the successional forests of Connecticut in spite of the chestnut blight. Chestnut stems are especially impressive in defoliation-induced canopy gaps where they sometimes attain a diameter greater than 15 cm and appear to reach canopy level only a few years after release. Five sites containing natural openings of various sizes and one site subjected to selective logging were investigated by coring chestnut stems and surrounding canopy trees. All chestnut sprouts subjected to strong release under natural canopy openings exhibited cores with 1-3 decades of slow growth followed by very rapid diameter increase. The relatively good form of these chestnut stems, therefore, resulted from rapid changes in stem form and not by resprouting from root systems. Apparently, initial suppression in shrub-like form was a natural step in canopy emplacement for the chestnut. This reproductive strategy appears especially effective under severe competition with shrubs on poor sites. Modern study of chestnut ecology is important because an increase in the proportion of chestnut pollen is a characteristic indicator of the most recent climate zone inferred from pollen profiles in New England. The role of chestnut as a climatic indicator is explained best by a complex process of soil impoverishment and organic litter build-up analogous to a widely accepted theory for the late Holocene development of blanket bogs in western Europe.