Mississippi’s landscape is comprised of sixtyive percent forest and is a vital artery for the state economy. Each year, an average of 4,000 wildfires occur that burn more than 60,000 acres statewide. This study examines correlations of cumulative precipitation for Mississippi’s nine physiographic regions during 1991– 2005 with total number of acres burned during peak wildfire season in Mississippi. Statistical analyses suggests that significant correlations exist between the cumulative precipitation at one, two, and three months prior to Mississippi’s early wildfire season and the total number of acres burned and the total number of fires. These findings, in conjunction with ongoing Mississippi wildfire research, may be incorporated into a potential predictive fire risk model for the state of Mississippi.

The research was undertaken to provide basic information on Mn in Virginia soils and to evaluate rates and methods of Mn application to correct Mn deficiency in soybeans. Soil profile samples were analyzed from catenas representing the Appalachian, Piedmont, and Coastal Plain regions. The exchangeable, easily reducible, and total Mn contents were higher in the Appalachian soils than in the Piedmont or Coastal Plain soils. The total Mn content of the well-drained soil was higher than the poorly-drained soil in the Appalachian catena. No other differences were found between soils varying in drainage. Parent material and time appear to be the soil forming factors that exert the largest influence on total soil Mn. Further research is necessary to fully characterize soil Mn in these broad physiographic regions. / Ph. D.

Experiments were conducted to study variation in the amount of podophyllotoxin in J. virginiana across nine –physiographic regions of Mississippi. The aim was bioprospection of podophyllotoxin from J. virginiana across Mississippi. Experiments were also conducted to utilize biproducts (i.e. needles) as a source of podophyllotoxin and essential oil. Dual extraction of both from the same plant material was obtained in order to develop economic protocol for industrial utilization. Three different experiments were conducted for the bioprospection and byproduct utilization of J.virginana. Experiment I: Study of variation in the amount of podophyllotoxin across nine physiographic regions and the study of contributing factors for the variability. Experiment II: Explore different plant parts as source of podophyllotoxin Experiment III: Establish a dual extraction protocol for extraction of podophyllotoxin and essential oil from J. virginiana.

Stand carrying capacity is the maximum size of population for a species under given environmental conditions. Site resources limit the maximum volume or biomass that can be sustained in forest stands. This study was aimed at estimating and determining the carrying capacity in loblolly pine. Maximum stand basal area (BA) that can be sustained over a long period of time can be regarded as a measure of carrying capacity. To quantify and project stand BA carrying capacity, one approach is to use the estimate from a fitted cumulative BA-age equation; another approach is to obtain BA estimates implied by maximum size-density relationships (MSDRs), denoted implied maximum stand BA. The efficacy of three diameter-based MSDR measures: Reineke's self-thinning rule, competition-density rule and Nilson's sparsity index, were evaluated. Estimates from three MSDR measures were compared with estimates from the Chapman-Richards (C-R) equation fitted to the maximum stand BA observed on plots from spacing trials. The spacing trials, established in the two physiographic regions (Piedmont and Coastal Plain), and at two different scales (operational and miniature) were examined and compared, which provides a sound empirical basis for evaluating potential carrying capacity. Results showed that the stands with high initial planting density approached the stand BA carrying capacity sooner than the stands with lower initial planting density. The maximum stand BA associated with planting density developed similarly at the two scales. The potential carrying capacity in the two physiographic regions was significantly different. The value of implied maximum stand BA converted from three diameter-based MSDR measures was similar to the maximum stand BA curve obtained from the C-R equation. Nilson's sparsity index was the most stable and reliable estimate of stand BA carrying capacity. The flexibility of Nilson's sparsity index can illustrate the effect of physiographic regions on stand BA carrying capacity. Because some uncontrollable factors on long-term operational experiments can make estimates of stand BA carrying capacity unreliable for loblolly pine, it is suggested that the stand BA carrying capacity could be estimated from high initial planting density stands in a relatively short period of time so that the risk of damages and the costs of experiments could be reduced. For estimating carrying capacity, another attractive option is to choose a miniature scale trial (microcosm) because it shortens the experiment time and reduces costs greatly. / Master of Science

The research was undertaken to investigate the impact of the Tshivhase Tea Estate on the space economy of Venda, the people and area ofMapate, and Duthuni, among whom the Tea Estate is established. The approach is based on principles. Principles of development theory are combined with appropriate spatial models. The development reality of Venda, together with many other development projects are analysed. Does the tea estate address the rural poverty problem? Findings are presented from a case study of Tshivhase and this proved the lack of growth and development impulses to alleviate the poverty of the rural people among whom it is located. Development is considered in terms of its possible simultaneous diffusion of economic activity and modernisation in all four dimensions of the spatial system : political, socio-cultural, economic and physical. / Department of Geography / M.A. (Geography)

The research was undertaken to investigate the impact of the Tshivhase Tea Estate on the space economy of Venda, the people and area ofMapate, and Duthuni, among whom the Tea Estate is established. The approach is based on principles. Principles of development theory are combined with appropriate spatial models. The development reality of Venda, together with many other development projects are analysed. Does the tea estate address the rural poverty problem? Findings are presented from a case study of Tshivhase and this proved the lack of growth and development impulses to alleviate the poverty of the rural people among whom it is located. Development is considered in terms of its possible simultaneous diffusion of economic activity and modernisation in all four dimensions of the spatial system : political, socio-cultural, economic and physical. / Department of Geography / M.A. (Geography)