Regeneration Dynamics in Old -Growth and Second-Growth Southern Appalachian Cove Forests

150 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2004.Regeneration dynamics in an old-growth and a second-growth cove forest in the Great Smoky Mountains of eastern Tennessee were studied over the course of four contiguous growing seasons. Woody shrub and herbaceous species in the regeneration layer were also investigated. The effects of disturbance and seasonal light availability, as measured by the analysis of hemispherical photographs, were expected to be the major sources of variation explaining differences in regeneration composition and dynamics. Overall seasonal light availability was not found to be significantly different between the two sites, but was significantly higher in canopy gaps in the old-growth site. Results of multivariate direct gradient analyses indicated that light availability played an important and often significant role in the distribution of species in the study sites and in several measures of regeneration dynamics. This role was most pronounced in comparisons between canopy gap and closed canopy plots at the old-growth site. Regeneration density was significantly higher in the old-growth site, but regeneration diversity was significantly higher in the second-growth site. Regeneration density, species richness, and diversity were found to be significantly higher in canopy gaps than beneath a closed canopy at the old-growth site. At the stand level, regeneration recruitment and mortality rates were found to be significantly higher in the old growth site, but no overall differences in growth or survival were found. Diameter growth, height growth, and survival rates were, however, found to be significantly higher in canopy gaps at the old-growth site. Intolerant species such as yellow-poplar were found to occur only within canopy gaps at the old-growth site, and evidence for the spatial partitioning of some tolerant species along a distance gradient from canopy gap centers was found to occur. The herbaceous community in the second-growth forest, including vernal species, had a higher density, species richness and diversity than in the old-growth forest.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD