Publication

The pattern of stand development was studied in two mixed-species single-aged stands that originated after true clearcutting at the Great Mountain Forest in northwestern Connecticut. One stand was located on a mesic swale-till site and the other on a more xeric thin-till site. At the time of cutting all sprout growth and advanced regeneration was eradicated, except for 1-year-old red oak (Quercus rubra) seedlings. Twenty-eight years after the stands originated trees were stratified by shade tolerance such that the canopies were dominated by the intolerant species (paper birch Betula papyrifera, gray birch B. populifolia, pin cherry Prunus pensylvanica) with mid-tolerant species (black birch B. lenta, black cherry P. serotina) becoming prevalent. The number of stems was decreasing but the basal area was steadily increasing. The pattern in species-specific growth rates and crown position were common to both sites; but there: were also differences between the sites in the sizes of trees and positioning of the mid-tolerant trees in the canopy. At age 28 the more mesic swale-till site had fewer, taller trees, with pioneer species more typical of northern hardwood climates. On this site red oak was doing poorly, all gray birch and eastern white pine (Pinus strobus) had died, black birch and black cherry were beginning to dominate the canopy of the stand, and a significant understory of beech (Fagus grandifolia) had developed through the encroachment of root suckers from the stand edge. Sugar maple (Acei saccharum), white ash (Fraxinus americana) and eastern hemlock (Tsuga canadensis), all significant components of the swale-till site before clearcutting, were noticeably absent. On the thin-till site red oak had not attained the canopy of the stand but was still a significant component of the mid-story with red maple (A. rubrum). However, black birch was self-thinning more rapidly on the thin-till site than that of the swale-till suggesting that red oak and red maple might well dominate the canopy within another 20 years. In general, the diameter growth rate of the thin-till site currently lags behind the swale-till by approximately 10 years. (C) 1999 Elsevier Science B.V. All rights reserved.