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  • 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.
1

Tree-Rings and the Aging of Trees: A Controversy in 19th Century America

Briand, Christopher H., Brazer, Susan E., Harter-Dennis, Jeannine M. January 2006 (has links)
During the late 19th Century there was considerable debate in the United States among members of the legal profession, the general public and even some scientists about the validity of using tree rings to determine tree age. In an earlier boundary dispute case in Maryland (1830) the Honorable Theodorick Bland rejected the use of tree rings to establish the date when a purported witness tree was marked with an identifying blaze. Bland did not believe that there was enough scientific evidence or legal precedent to support this idea. A review of the current scientific literature of the time, however, indicates that most scientists, especially in Europe, accepted that tree rings could be used to determine age. In the United States, however, this idea was debated, particularly in the late 19th Century, in both the popular press and scientific publications. The main argument of opponents such as A. L. Child was that the number of tree rings was often wildly in excess of the known age of the tree. These inconsistencies were likely because of the inexperience of the observer, mistaking earlywood and latewood for separate rings, and the presence of a small number of false rings, sometimes called secondary rings. The great ages reported for the giant sequoias may have also raised doubts among the public. Among scientists, however, the relationship between ring number and tree age and between ring width and climate became widely accepted. Several cases heard in both Federal and State Courts as well as Bernhard E. Fernow’s Age of Trees and Time of Blazing Determined by Annual Rings laid to rest any doubt of the relationship between tree rings and age in temperate forests, i.e. one ring equals one year’s growth, and showed that the date when a witness tree was blazed could be easily determined from a cross-section of the trunk.
2

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

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