Date of Award
Master of Science
Ecology and Evolutionary Biology
J. Frank McCormick
H. R. DeSelm, Frank W. Woods
Vegetation patterns approximately 50 years after the chestnut blight were examined in forest stands of the Great Smoky Mountains National Park. Specific objectives of this study were: (1) to determine the present composition of replacement stands following the elimination of chestnut, (2) to examine selected site factors and to relate them to tree species composition, (3) to project future trends in the composition of the replacement stands, and (4) to compare these results with earlier results and predictions of Wood and Shanks (1959) concerning chestnut replacement in the same area.
Data were analyzed from 38 sample plots ranging from 2000 to 4000 feet elevation in the eastern portion of the Great Smoky Mountains National Park.
Species most often involved in chestnut replacement are red maple, northern red oak, sourwood, and chestnut oak. Red maple do not show noticeable differences in importance with respect to moisture conditions. However, mesic species such as northern red oak, hemlock and silverbell are more important under favorable moisture conditions. Chestnut oak and sourwood are more important under relatively xeric conditions.
Species importance values were used to group sample plots into replacement forest types using an agglomerative clustering procedure.
Six replacement forest types were identified; Silverbell-red maple, hemlock-hardwood, northern read oak-silverbell, chestnut oak, red maple-oaks red maple-sourwood.
Discriminant analysis based upon vegetation data indicated that 97% of the samples were correctly identified. Discriminant analysis using environmental variable indicated that environmental conditions in the various replacement forests were not entirely distinct. Elevation and moisture conditions appear to be the most important factors responsible for distinct chestnut replacement types.
In the present study, chestnut stump basal area was not an important variable in segregating the chestnut replacement forests. However this may be due to the fact that all sites selected for study has high basal area of chestnut stumps.
Results of this study suggest that chestnut is being replaced in the Smokies by the same species that were its earlier associated, mainly red maple, chestnut oak and northern red oak. Under the most mesic conditions, chestnut is being rapidly replaced by species such as hemlock and silverbell. Under the most xeric conditions, the process or recovery is slow; red maple and sourwood have been most favored by the death of chestnut. Red maple is an important species in several of the replacement forest types.
Chestnut is not being replaced by a single vegetation forest type. Six distinct successional forest types presently occur on sites formerly dominated by chestnut. Subsequent and periodical studies are recommended in order to determine if current trends will continue.
Arends, Ernesto, "Vegetation Patterns a Half Century Following the Chestnut Blight in the Great Smoky Mountains National Park. " Master's Thesis, University of Tennessee, 1981.