Patterns of Abies fraseri Regeneration in a Great Smoky Mountains Spruce-Fir Forest

Abstract

PAULEY, E. F. AND E. E. C. CLEBSCH (Graduate Program in Ecology, University of Tennessee, Knoxville, TN 37996-1610. Pattems of Abiesfraseri regeneration in a Great Smoky Mountains spruce-fir forest. Bull. Torrey Bot. Club 117: 375-381. 1990.-Abiesfraseri (Pursh) Poir. (Fraser fir) has incurred high mortality from infestation by Adelgespiceae Ratz. (balsam woolly adelgid). Vegetational changes in the spruce-fir forest since Adelges infestation have included a large increase in the density of Rubus canadensis L. (thomless blackberry). Size and age structures, microsite and aspect distributions, and growth of Abies seedlings (stems < 137 cm tall) were quantified on Mt. Collins, Great Smoky Mountains National Park in 1988 to determine pattems of co-occurrence between Abies seedlings and Rubus. The majority (87%) of seedlings were c25 cm tall, and most (62%) were at least five years old. No germinal (< 1 year old) Abies were found. Dead wood substrates and bryophyte-covered surfaces both supported more seedlings than expected by chance. Seedling growth trends showed a recent increase in terminal shoot length and recent decreases in lateral shoot lengths, suggesting a combination of normal growth pattems and recovery from Adelges infestation. Effects of Adelges infestation were noted for 26% of all seedlings and were more frequent among older seedlings. Density of Abies seedlings was low at high Rubus densities, but seedling shoot growth showed no clear relationship with Rubus density. Rubus appeared to interfere with establishment or survival of Abies seedlings but not with annual growth.