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Vegetation Dynamics of a Carolina Hemlock Community at Bluff Mountain, North Carolina, USA

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
David Alan Austin (Creator)
Institution
Appalachian State University (ASU )
Web Site: http://www.library.appstate.edu/
Advisor
Saskia van de Gevel

Abstract: The goal of this thesis was to examine the Carolina hemlock (Tsuga caroliniana Engelm.) forest at the early onset of hemlock woolly adelgid (Adelges tsugae Annand) infestation to establish baseline data used to measure anticipated changes in Carolina hemlock forest dynamics. I quantified the composition and structure of the Carolina hemlock forest overstory and understory, as well as collected increment cores from all trees within five 0.05 ha plots located in Carolina hemlock dominated stands. Based on basal area and canopy class, Carolina hemlock was the most dominant species in the understory and overstory. The diameter distribution and density of seedlings and saplings indicated that Carolina hemlock is successfully and continuously regenerating. The stand had several characteristics indicative of old-­--growth status with gap-­--phase dynamics. I used dendroecological techniques to quantify the frequency and spatial distribution of canopy disturbances during the period of AD 1870-­--2000, examined climate-­--growth relationships, and determined if there was an age-­--related difference in the climate-­--growth relationship. There were no stand-­--wide disturbance events, only gap-­--phase dynamics. Analysis of the climate-­--growth relationships indicated that older Carolina hemlocks prefer cool, moist summers. There were age-­--related differences in climate response as younger Carolina hemlock were less responsive to precipitation and PDSI than older Carolina hemlock. However, both older and younger had a negative relationship between radial growth and temperature during the month of May and July, respectively. I also used tree age data to conduct a preliminary study investigating the influence of age on foliar nitrogen and carbon content and found an increase in nitrogen content with tree age. Future research on Carolina hemlock at Bluff Mountain will include resampling plots and using the results of this thesis to quantify changes in stand structure and composition of the Carolina hemlock forest. Understanding the dynamics of the Carolina hemlock forest at the site level will provide insight about the anticpated changes across the species’ range. This information will serve land managers attempting to preserve Carolina hemlock and the wildlife that relies upon this species.

Additional Information

Publication
Thesis
Austin, D.A. (2012). Vegetation Dynamics of a Carolina Hemlock Community at Bluff Mountain, North Carolina, USA. Unpublished master's thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2012