• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • Tagged with
  • 23
  • 23
  • 8
  • 5
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Successive Land Surveys as Indicators of Vegetation Change in an Agricultural Landscape

Flatley, William Truetlen 19 October 2006 (has links)
A series of anthropogenic disturbance conditions have altered the vegetation of the southern Appalachians during the past 200-years. The objective of this research was to identify the nature and timing of these vegetation changes in order to better understand the underlying causes. A total of 304 land surveys were collected for a small agricultural watershed from early settlement in 1787 through to the present day. Witness corners recorded tree species, shrubs, stumps, snags and non vegetative markers. Types of witness corners were tallied and tested for shifts in frequency across time periods. Tree species were also classified by silvical characteristics including sprouting capability, shade tolerance, and seed type and these groupings were tested for shifts in frequency across time periods. Landform bias of the witness corners was tested using references contained in the surveys. Results showed significant shifts in white oak (Quercus alba L.), chestnut (Castanea dentate Marsh. Borkh.), chestnut oak (Quercus prinus Wild.), black oak (Quercus velutina Lam.), red oak(Quercus rubra L.), black locust (Robinia pseudoacacia L.), yellow poplar (Liriodendron tulipifera L.), and scarlet oak (Quercus coccinea Muenchh.). The central change was a steady decline in white oak, probably due to the absence of fire and changes in soil properties. Chestnut replaced white oak as the dominant species, but was removed by chestnut blight in the 1930's. Sprouting capability appeared to be the most important silvical characteristic across all species. / Master of Science
22

Breeding Bird Census to Compare Long-term Changes in the Avifauna of the Spruce-fir Forest on Mount Guyot, Great Smoky Mountains National Park 1967-2015

Brooks, Kevin C 01 December 2015 (has links)
The high-elevation forests of the Southern Appalachian Mountains have been impacted and rearranged by a tiny introduced pest from Europe, known as the Balsam Woolly Adelgid (Adelges piceaea), creating a concern for conservation. Breeding bird censuses, along with botanical surveys, have been conducted periodically on an established 60-acre plot since 1967 on the virgin forested slopes of Mount Guyot, Great Smoky Mountains National Park, with the last census being completed in 2015. Breeding bird populations are shown to rise and fall in response to the forest’s changes over the last 48 years. Comparisons are made between all studies in order to assess how bird populations are being affected by the changed forest dynamics.
23

A Dendrochemical Analysis of Lead, Aluminum, and Calcium in Southern Appalachian American Beech.

Southerland, Laura Suzanne 01 May 2001 (has links) (PDF)
The health of the northern hardwood forest in the Southern Appalachian Mountains of Tennessee, North Carolina, and Virginia has recently gained attention from the media and environmental stakeholders. This project was designed to examine concentrations of metals, including lead, aluminum, and calcium in growth rings of an important northern hardwood species, American beech (Fagus grandifolia Ehrh.) at Mount Rogers and Whitetop Mountain, Virginia. Dominant and codominant trees were sampled from sixteen research plots located at two different elevations. Samples were crossdated, divided into sections of ten-year periods, and analyzed using atomic absorption spectroscopy. Concentrations of metals were negatively correlated with ring width. Elevation and aspect were significantly associated with the concentration of the cations analyzed. Both lead and calcium concentrations increased during the 1860s and again during the mid-1900s. This increase in lead and calcium may suggest the mobilization of these elements in soil.

Page generated in 0.0712 seconds