The effects of crop tree release and fertilization of young yellow-poplar on low and medium quality Southern Appalachian sites were compared. In June of 1989 96 individual 10 year-old yellow-poplar crop stems were treated in factorial combinations. The crop trees were either released, using a 4% triclopyr ester in kerosene basal spray. fertilized with 224, 291 and 243 kg/ha of N, P, and K; released and fertilized, or left untreated. These treatments were repeated in June of 1992. In 1992, treatments were slightly different. Crop trees were released mechanically, and only nitrogen was applied at 224 kg/ha. After five years, only release resulted in significant growth responses. Released trees responded positively to increased sunlight and horizontal space by increasing their uptake of nitrogen and iron - elements essential for photosynthesis. This led to an increase in foliage production, and presumably, an increase in total photosynthesis. Released trees reacted to the increased growing space by filling in the space created by release. Released trees increased both diameter and crown volume growth; unfortunately, they did so at the expense of height growth, which was decreased by crop tree release. Current stem wood volume, was therefore not increased. / Master of Science

During the third growing season after thinning, eight-year-old loblolly pine gas exchange parameters were measured. Full sunlight and stand light conditions for upper (sun) and lower (shade) crown foliage were examined. Xylem water potential, litterfall dynamics and tree growth were monitored. Nutrient availability, chlorophyll content and chlorophyll a/b ratio were assessed. At the end of the third post-thinning growing season (eleventh season since planting), thinned trees had larger stem and crown diameters, and live crown ratios. Thinned trees grew 11 cm more in height, and approximately 35% more in diameter, basal area and volume. Only crown diameter differences were statistically significant at p=0.05. Upper crown foliage was found to have somewhat higher net photosynthesis, stomatal conductance and transpiration when measured under saturating light conditions. Lower crown needles displayed features usually associated with shade foliage: lower photosynthetic capacity, lower light compensation point and dark respiration rates. Observed physiological differences were not related to plant water status, chlorophyll content or chlorophyll a/b ratio. The higher light saturated gas exchange rates for upper crown foliage were paralleled by lower stomatal limitations to photosynthesis, possibly the effect of better potassium supply facilitating more efficient stomatal function. Light conditions in thinned stands did not differ significantly between the upper and lower crowns, even though light levels in the lower crowns of unthinned stands were nearly a third of that in the upper crowns. This had an effect on in situ photosynthetic rates, which were similar in the upper and lower crowns of thinned trees. In situ photosynthetic rates in thinned stands were also similar to those measured under saturating light. In the unthinned stands, because of light differences, gas exchange rates were significantly reduced in the lower crowns, with only upper crown foliage fully utilizing its potential for photosynthesis. The physiological activity in the upper crowns of unthinned trees tended to be even higher than in the upper crowns of thinned trees. Litterfall timing did not differ between the thinned and unthinned stands. Litterfall per hectare was higher in unthinned stands, but when expressed on a per tree or unit basal area basis it averaged higher in thinned stands. A larger photosynthetic apparatus together with full utilization of photosynthetic potential in both crown positions are likely the major reasons for better growth of thinned trees. / Master of Science

The influence of thinning at age eight on the photosynthetic rate, needle conductance, xylem water potential, water use efficiency and growth of loblolly pine trees was studied during their ninth and tenth growing seasons. Litterfall dynamics were monitored throughout the study period as well. At the end of the second post-thinning growing season, trees in thinned plots had greater stem diameters, greater live crown ratios, greater live crown diameters and greater average volumes and basal areas than did trees in control plots. Significant physiological changes due to thinning were observed only in the lower crowns where needles were found to adapt to the sudden increase in available light by adjusting their physiology to resemble that of sun needles. Lower crown photosynthesis and needle conductance in thinned plots were more similar to upper crown values for these parameters than to lower crown, control plot values. Foliage produced during the current year and measured after full elongation had a higher average photosynthetic rate, needle conductance and lower average water potential than did foliage in its second growing season during both 1988 and 1989. Additionally, the water use efficiency of current-year foliage was significantly greater than that of the second-year foliage. In both thinned and control plots, significant diameter growth and photosynthesis continued throughout the dormant season although at a slower rate than during the growing season. Litterfall timing did not differ between thinned and control plots, nor did the amount of litterfall per unit basal area during the first year following thinning. Partial second-year data suggest that subsequent litterfall amounts will mirror the greater average crown size in thinned plots. / Master of Science

M.S.

Thesis (M.S.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 91-97). Also available via Humboldt Digital Scholar.

I examined impacts of thinning on bird population densities and habitat use in Appalachian mixed-hardwood forests during 1984 and 1985 at three thinned and three unthinned stands in the Jefferson National Forest, southwestern Virginia. Densities of shrubs, saplings, trees, and snags, canopy and ground cover, and foliage volume were the structural variables most influenced by thinning. Populations of shrub/understory birds were higher in thinned stands than unthinned stands. Canopy-dwelling species showed variable population responses to thinning. Habitat use similarities were used to group 13 bird species into three categories: (1) shrub/conifer species included the tufted titmouse, blue-gray gnatcatcher, wood thrush, ovenbird, and hooded warbler, (2) generalist species included the eastern wood-pewee, red-eyed vireo, black-and-white warbler, and scarlet tanager, and (3) mature/deciduous species included the white-breasted nuthatch, solitary vireo, blackburnian warbler, and worm-eating warbler. Shrub, snag, and conifer density and ground cover were the four habitat variables most important in separating used from unused sites. Foraging behavior and resource use of seven bird species were examined in two thinned and two unthinned stands. No differences in foraging methods or niche breadth were found between the stands for all species. Differences in foraging and tree heights were due to tree height differences between the stands. For most species, foraging resource use was equal to availability. Short, small diameter trees were rarely used. Oaks were used most often, and red maple and conifers were rarely used for foraging. The opportunistic nature of avian foraging behavior and the vegetative differences between thinned and unthinned stands led to the foraging differences noted. / Master of Science

"SELECT CD is a site-specific, decision-support tool for selecting ecologically viable tree species, reproduction cuttings, and regeneration methods in the coastal forest (CDF, CWH, and MH zones). SELECT CD integrates information from several existing guides with new information from literature and recent research into a single, user-friendly resource. SELECT CD also includes a rich library of visuals and an illustrated glossary of technical terms."

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 161-175).

Thesis (M.S.) -- University of Tennessee, Knoxville, 2005. / Title from title page screen (viewed on Feb. 1, 2006). Thesis advisor: David S. Buckley. Vita. Includes bibliographical references.

No description available.