Abstract
Fifty-year records (52–53 years) from 29 cruise plots on the Bartlett Experimental Forest, New Hampshire, indicated that composition is moving toward a predominance of one or two tolerant species in response to soils (habitat) and, to a lesser extent, elevation. Plots on fine till are moving toward American beech (Fagusgrandifolia Ehrh.) and sugar maple (Acersaccharum Marsh.), with some indication that perpetuation of sugar maple in this region of granitic soils depends upon canopy disturbance. Stands on coarse washed (sandy) till are moving toward beech, with some representation of tolerant conifers. Plots with shallow basal till (well drained to poorly drained), shallow bedrock, or ice-contact gravel are moving toward eastern hemlock (Tsugacanadensis (L.) Carr.) and (or) red spruce (Picearubens Sarg.). Eastern hemlock is successful below elevations of 500–550 m, while red spruce is successful at higher elevations.