Twenty-five Years of Succession in the Spruce-Fir Forest on Mount Rogers in Southwestern Virginia


Harold S. Adams

Additional Authors:

Steven L. Stephenson


June 2010


ABSTRACT Four study areas located within the Fraser fir (Abies fraseri)-red spruce (Picea rubens) forest on the summit of Mount Rogers in southwestern Virginia sampled originally in July 1982 were resampled during June 2007. Mount Rogers is the northernmost locality for Fraser fir, a species that has suffered serious damage over the past half century from the introduced balsam woolly adelgid (Adelges piceae). Both total basal area (m2/ha) and density (number/ha) of trees ($10 cm DBH) increased during the 25 year interval between the two sampling dates, whereas basal area of small trees ($2.5–9.9 cm DBH) increased and density decreased. Much of the change in overall composition was due to the decrease in importance of red spruce with a concurrent increase in importance of Fraser fir. The most striking differences were noted for saplings (stems $1 m but ,2.5 cm DBH), with those of Fraser fir and red spruce decreasing from 5,725 to 550 and 475 to 0 stems/ha, respectively. In addition, cover of herbaceous plants declined during the 25 years while bryophyte cover increased. Mean age of representative larger red spruce and Fraser fir trees cored in 2007 (83 years) was comparable to the value recorded in 1982 (84 years). These data suggest that many of the older individuals present in the community in 1982 were no longer present in 2007.