High elevation Fraser fir (Abies fraseri) forests of the Southern Appalachians have undergone widespread mortality since the introduction of the balsam woolly adelgid in the 1950s. Resulting changes in ecosystem pattern and process (e.g., stand dynamic processes) have greatly affected floral and faunal communities. In this project, we integrated field observations, geographic information system topographic models, and 1988–1998 satellite imagery to analyze spatial and temporal conditions of Fraser fir and spruce-fir ecosystems in Great Smoky Mountains National Park. Tasseled cap indices (brightness, greenness, and wetness) and associated spectral changes for Landsat TM digital data were statistically modeled by topographic variables. Spectral changes were recorded using change vector analysis (CVA) and spherical geometry at multiple scales: individual sites, local ridges, and across the east-west gradient of the study area. Significant relationships were found between elevation and observed spectral changes and among mountain sites representing the east-west chronosequence of adelgid infestation. Topographic derivatives were related to tasseled cap and CVA measures in summary statistics, regression, and correlation analysis, revealing significantly different mortality and regeneration pathways that were a function of topographic settings. Geographic variations of these vectors also detail the scope of east-west and localized upslope progression of fir mortality. The application of CVA provided the ability to summarize variation in spectral changes (magnitude and direction) and to ascribe measures to mortality and regeneration processes.
Original Publication Citation
Allen, T. R., & Kupfer, J. A. (2001, 2001/09/01). Spectral response and spatial pattern of Fraser fir mortality and regeneration, Great Smoky Mountains, USA. Plant Ecology, 156(1), 59-74. https://doi.org/10.1023/A:1011948906647
Allen, Thomas R., "Spectral Response and Spatial Pattern of Fraser Fir Mortality and Regeneration, Great Smoky Mountains, USA" (2001). Political Science & Geography Faculty Publications. 33.