Doctoral Dissertation Research: A Multi-Scale Analysis of Disturbance, Dynamics, and Climate-Growth Relationships in Mountain Longleaf Pine Forests, USA

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

This research integrates geospatial and ecological approaches to examine the roles of climate, competition, disturbance, and human activities in regulating the composition and structure of old-growth and second-growth mountain longleaf pine forests of the southeastern United States. Mountain longleaf pine forests are relatively understudied components of the imperiled and highly diverse longleaf pine ecosystems that historically dominated the Coastal Plains and parts of the Piedmont, Ridge and Valley, and Southwestern Appalachians. These mountain forests are at the northern latitudinal and altitudinal range margin for longleaf pine ecosystems. Doctoral student Arvind Bhuta, under the supervision of Dr. Lisa Kennedy at Virginia Tech will produce a high-resolution (temporal and spatial) reconstruction of competition and disturbance at multiple mountain longleaf pine sites. Randomly placed study plots in mountain longleaf pine forest sites will be surveyed for forest structure and composition. All canopy trees within the plots will be identified, measured, referenced with a global positioning system, and cored. Analysis of forest metrics in a geographic information system will document forest processes and patterns at multiple spatial scales ranging from individual tree species and communities to the broader ecosystem. Annual rings from each tree will be measured, standardized, and statistically analyzed. Tree rings provide an annual-resolution record of tree growth, forest composition and structure, and proxy records of climate, disturbance, and competition through time. Historical tree growth will be linked with current forest metrics, land-use history, and climate records to provide detailed information on long-term forest dynamics and the drivers of change in this ecosystem. The investigation of the relationship between climate and longleaf pine radial growth will allow for comparisons to be made between sites at the range margin and others throughout its range to better understand the geographic variation in the climate response of this species. Mountain longleaf pine forests are economically and biologically valuable. They are high in biodiversity and rich with endemic herbaceous and vertebrate species some of which are now rare and endangered due to intense land-use patterns, fragmentation, and the disruption of the natural fire regime. Long-term records of forest dynamics across multiple sites will provide context for sound decisions on the restoration and management of these forests and its vulnerable species, such as the red-cockaded woodpecker and the Cumberland azalea. This research will fill a critical gap in the knowledge of mountain longleaf pine forests by providing new information on the ecological drivers of ecosystem and community processes and patterns which could be influenced by climate change. Land managers of mountain longleaf pine forests have based management and restoration practices on studies that focused on individual stands and short time scales, many at lowland sites that may differ in ecological function. In contrast, this research will account for pattern and processes over large temporal and spatial scales.