Thesis (M.S.) in Forestry--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 53-58).

A greenhouse study was undertaken to investigate some relationships between nutrition of the host tree, Abies amabilis, as influenced by soil fertility and nitrogen fertilizers, and biology of the balsam woolly aphid, Adelges piceae (Ratz.). Seedlings were reared in two soil regimes - nutrient-deficient mineral soil and enriched humic soil. All trees were infested with aphid larvae, and observations made to determine the influence of soil fertility on the establishment rate of larvae on host trees. Subsequently, groups of 10 trees were treated with foliar nutrients, using ammonium nitrate and urea in various concentrations. The establishment rate of larvae on humic soil host trees was 2.5 times greater than on mineral soil trees. In addition, growth rate of the aphid population on humic soil trees was 37% greater than on mineral soil trees over a four week period. Soil fertility also influenced the life history of the insect. One foliar nutrient adversely affected the aphid population. Over a 10 week period, the aphid population on trees treated with 1% ammonium nitrate decreased by 23%, whereas the control population Increased 30.9%. It is postulated that this foliar treatment manifests its adverse effect primarily by inhibiting initial settling of larvae on the host trees. This inhibition may be related to fertilizer-induced alterations in the amino acid composition of feeding tissue. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (M.S.)--Virginia Polytechnic Institute, 1967. / Typescript (photocopy). Vita. Abstract (2 leaves) bound with copy. Includes bibliographical references (leaves 83-89). Also available via the Internet.

No description available.

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.

Over the past several decades, naturally occurring populations of Fraser fir (Abies fraseri) in the Black Mountains of North Carolina have been heavily impacted by both direct and indirect anthropogenic disturbances, including logging and logging- associated fires, and high mortality rates due to the introduction of the exotic insect, balsam woolly adelgid (BWA) (Adelges piceae). The decline in Fraser fir is particularly concern because it serves as a foundation species within the spruce-fir forests of the Southern Appalachian Mountains. Our objectives for this research were to 1) use current stand structure to infer whether Fraser fir trees are experiencing a cycle of regeneration-mortality that will lead to eventual decline of the population, 2) determine what role, if any, the site-specific geographic variables of slope, elevation, aspect, and land use history have on stand structure, mortality, and BWA infestation level, and 3) analyze repeat aerial photography to examine broad trends of spruce-fir forest cover change caused by anthropogenic disturbance and the BWA. In order to understand stand structure, mortality, and infestation levels, we conducted detailed field surveys of Fraser fir trees throughout the Black Mountains using 44, fixed-radius circular sampling plots. These plots were placed throughout a series of aspects, elevations, and disturbance types in order to understand geographic variability among these variables. An analysis of 4 repeat aerial photographs and corroborating ground photographs revealed broad spatio-temporal trends of spruce-fir regeneration and mortality from 1954 to 2006. Our results indicate that Fraser fir stands at higher elevations are currently in a state of recovery; whereas stands at lower elevations appear to be more susceptible to BWA-induced mortality. Changes in forest cover area from 1954 to 2006 were influenced greatly by direct and indirect anthropogenic disturbance. Our results call attention to the significant impact that direct and indirect anthropogenic disturbance has had on Fraser fir stand structure, but also provide evidence for the ability of an imperiled ecosystem to recover from high rates of insect caused mortality. / Master of Science