Archaeological surveys using the subsurface testing method known as “shovel-testing” have been performed sporadically across the Bienville National Forest in central Mississippi. However; no research-oriented analysis has ever been performed for this area. The Bienville National Forest is located primarily in two physiographic regions: the Jackson Prairie and the Southern Pine Hills. These two regions are distinctly different in topography, soils, and vegetation. No settlement pattern study has been performed in the Jackson Prairie and it has been viewed as an area of low probability. Soils in this region are often heavy clays with high shrink/swell capabilities and poor drainage. In this thesis, I attempt to construct an initial analysis by looking at the duration of occupations and their placement in the landscape through time in order to determine whether the Jackson Prairie played any important role in the choice of habitation locations by prehistoric populations.

Planted pine (Pinus spp.) comprises nearly 10% of the total land cover in the state of Mississippi. Often, understory structure is limited in this system. Thus, managers use a variety of management practices to improve understory biomass and structure. I assessed the impacts of common forest management practices (canopy reduction, prescribed fire, and selective herbicide application) and their combined effects on aspects of community structure. More specifically, I assessed impacts of disturbance intensity on non-native plant invasions, and evaluated how microscale vegetation characteristics influenced use by white-tailed deer (Odocoileus virginianus) and wild turkey (Mealagris gallopavo). Combining canopy reductions with prescribed fire, which closely mimicked historical intermediate disturbance intensities in this vegetation type, led to the greatest invasion resistance due to high abundances of native plants. Both deer and turkey increased use in areas with high levels of understory cover. Coupling canopy reductions with prescribed fire created the most favorable conditions for both species.

To provide fundamental information for the second generation of cross laminated timber manufacturing, wood sections that glued by different orientations were constructed and tested. To reveal adhesive differences, phenol resorcinol formaldehyde (PRF) and polyurethane (PU) adhesive were used and the gluelines were evaluated in accordance with different conditions for shear strength, wood failure, dimensional stability and delamination. A non-destructive testing method was applied to measure the dynamic modulus of elasticity (dMOE) change. The results showed that the radical wood section of lumber produced with the starsawn process had much less deformation and was more suitable for glueline. PRF had better performance than PU in terms of shear strength, dimensional stability, and delamination. Confocal microscopic pictures revealed that the tangential to tangential (TT) glueline showed the tendency of collapse, indicating a poor bond strength and therefore a poor glueline durability of TT glueline, especially when it was subject to wet conditions.

Cross Laminated Timber (CLT) is an engineered wood product consisting of an odd number (three to seven) of lumber layers, which are glued in an orientation of each layer perpendicular to other. After its introduction, CLT has been widely adopted in Europe since 1990s and has quickly become popular in the US in the last decade as a sustainable and cost-effective alternative to traditional building materials such as concrete and steel. The first version of PRG-320 was published in 2012 for the US and Canada to help designers and builders understand the properties of CLT and use it safely. The current version of PRG-320 only allows the use of softwood species for commercial production of cross-laminated timber (CLT) in the US. However, recent studies have investigated the possibility of using hardwood species for CLT and have shown promising results. In parallel to this, the next version of PRG-320 is being revised to include hardwood species. The inclusion of hardwood species is an effort to increase the value of underutilized wood species in the United States. This study presents the results from testing of three-layer and five-layer CLTs manufactured using yellow-poplar (Liriodendron tulipifera) as hardwood and southern pine (Pinus spp.) as softwood in different layers, defined as hybrid CLT. The purpose of this project was to compare the bending and shear properties in the major axis direction of hybrid CLT panels obtained from five-point, four-point, and three-point bending tests with the current ANSI/APA PRG-320 values, and also to evaluate their resistance to shear by compression loading and delamination according to ANSI A190.1 and AITC T110 standards, respectively. The bending strength and bending stiffness, except for some individual groups, as well as the shear strength and shear stiffness values exceeded the Grade V3 from PRG-320. However, the wood failure in resistance to shear by compression loading and face delamination in resistance to delamination were lower than the required values in the standards. The test results demonstrated that CLT groups consisting of yellow-poplar has strength and stiffness properties comparable to those consisting of southern pine. This suggests that yellow-poplar could be a promising alternative species to softwood in the production of CLTs. / Master of Science / Cross Laminated Timber (CLT) is a wood composite material made of lumbers that are oriented perpendicular to each other and glued together. CLT has quickly gained popularity in Europe since its introduction in the early 1990s and has become an attractive material in the United States in the last decade due to its sustainability and cost-effectiveness compared to traditional building materials. As a standardization effort, the first standard for CLT, PRG-320, was published for both the US and Canada as a guide for designers and builders to understand the properties of CLT and has allowed only softwood for the commercial production of CLT in the US since its initial version. The promising results of research on the use of hardwoods in CLT production have enabled efforts to include hardwood species in the next version of the PRG-320. This study presents the results from testing of three-layer and five-layer CLTs manufactured using yellow-poplar as hardwood and southern pine as softwood in different layers, defined as hybrid CLT. The purpose of this project was to compare the bending and shear properties in the major axis direction of hybrid CLT beams obtained from five-point, four-point, and three-point bending tests with current industry guidelines, and also to evaluate their resistance to shear by compression loading and delamination. The test results indicated that yellow-poplar possesses similar strength and stiffness properties to southern pine, indicating that it has potential to be used as an alternative to softwood species in CLT production.

Although it is common to model modulus of elasticity (MOE) and modulus of rupture (MOR) of graded lumber as normal, lognormal, or Weibull distributions, recent theories and empirical practices have cast doubt on these models. Mathematical proofs have been used to shown how the MOR distributions of graded lumber can be derived from the MOR distributions of mill-run populations. The MOR distribution of a graded lumber subpopulation is "pseudo- truncated" and does not exhibit the same theoretical form as the mill-run population from which it was drawn. Therefore, it is essential to explore the properties of mill-run lumber populations and properly characterize their MOE and MOR distributions. To investigate this topic, this dissertation has three objectives: 1) to determine if the within-mill means and standard deviations of MOE and MOR in mill-run southern pine (Pinus spp.) lumber differ over time, 2) to determine the correlations among hand-held grain angle meter readings, MOE, and MOR in mill- run southern pine lumber, and 3) to model statistical distributions of MOE and MOR in mill-run red pine (Pinus resinosa) and spruce (Picea spp.) lumber. This research features four main sections: 1) an introduction summarizing the conclusions of each chapter, 2) a chapter investigating if there are statistically significant differences between the means and variances of MOE and MOR in mill-run southern pine lumber populations at the same mill over time, 3) a chapter evaluating the bivariate correlations among handheld grain angle meter readings, MOR, and three measures of MOE in mill-run southern pine lumber, and 4) a chapter modeling the distributions of MOE and MOR in mill-run red pine and spruce lumber populations and comparing those to previous work on mill-run southern pine lumber populations.

This thesis has two data chapters that consider factors affecting loblolly pine health in localized regions of Mississippi. The first data chapter investigated the abiotic and biotic factors contributing to loblolly pine (Pinus taeda) mortality on private timberland in Mississippi. This assessment considered temperature and precipitation variations, bark beetle populations, foliar and root pathogen tests, and drone survey. The results revealed that the loblolly pine mortality resulted from combination of factors. The second data chapter examined the impact of habitat fragmentation on southern pine beetle (SPB; Dendroctonus frontalis) infestation in Homochitto National Forest (HNF). This was assessed through remote sensing and categorization of SPB spots in HNF over nine years. Results indicated that increased total pine patch area, decreased distance between pine patches, and low patch diversity are important drivers of SPB outbreak in HNF. These results can help improve loblolly pine health and management in the southeastern United States.

The hypothesis that stressed loblolly pine (Pinus taeda L.) could be distinguished from non-stressed loblolly pine by increased foliage temperatures was tested. The foliage temperatures of seedlings and trees were measured with an AGA Thermovision 680 system, imported by the AGA Corporation, Secaucus, New Jersey. The AGA Thermovision 680 system is a simple, easily transported remote sensing system for detecting relative apparent temperatures of plant foliage without direct contact with the leaves. This system is sensitive to infrared wavelengths in the 2-5.6 micron region of the electro-magnetic spectrum. Foliage temperatures in loblolly pine seedlings increased within one week of stress induced by drought, flooding, or severing. Increased temperatures of stressed seedlings were associated with reduced needle moisture content prior to visual symptoms of stress. Foliage temperatures of loblolly pine trees stressed by severing the bole were warmer relative to neighboring control trees. Increased temperatures were detected within one week after severing. Previsual detection of stress can be achieved by measuring foliage temperatures of loblolly pine. The AGA Thermovision should prove to be a useful tool for non-destructive sampling of plant stress, for locating stressed trees, and potential bark beetle infestations. / Ph. D.

Forest management practices which reduce southern pine beetle (SPB) risk benefit not only the landowners who perform them, but all those who draw benefits from southern pine forests in Virginia, especially other forest owners within the same region. One such management practice is pre-commercial thinning (PCT), which is particularly unattractive to non-industrial private forest (NIPF) landowners because of the substantial costs and delayed financial returns involved. Since the benefits to society generated by PCT are not fully realized by the individuals who might implement it, there may be a market externality in which PCT is underprovided across the landscape. The Pine Bark Beetle Prevention Program (PBBPP) has the potential to correct this externality by reimbursing a portion of the costs of PCT for landowners who qualify. However, cost share incentives have been criticized for being ineffectual on the basis that landowners substitute publicly funded reimbursement for private investment, without altering their management practices. To investigate the effect of the PBBPP cost share for PCT, a survey was sent to 1,200 NIPF landowners in seven counties across the Piedmont and Coastal Plain physiographic regions of Virginia, where southern pine is prevalent and SPB hazard is a relevant concern. To measure willingness to participate in the program, a referendum style question was used in which the offered cost share ranged from 20% to 90%. Results of discrete choice models estimated from survey data indicate that cost sharing has a significant, positive effect on willingness to participate overall, though increasing reimbursement above 60% is unlikely to affect participation. Some landowners are not responsive or are less responsive to cost sharing due to personal and property characteristics. / Master of Science

Since the introduction of management practices by the Forest Service to stabilize red-cockaded woodpecker (RCW) populations, the number of cavity trees killed by southern pine beetles (SPB) has increased. A model of the landscape ecology of RCW and SPB in the Homochitto National Forest was created using data collected from the Forest Service and Global Atmospherics. The conclusions of the study were that the RCW and SPB utilize the same type of habitat and the stand hazard maps are an accurate means of determining the locations of SPB infestations. The functional heterogeneity maps created for the SPB and RCW would be useful predictors of future occurrences of either species if complete data were obtained.

In this study, two symbiotic fungi of Southern Pine Beetle (SPB), Entomocorticium peryii and Entomocorticium sp.A were evaluated in terms of polyphenol oxidase (PPO) production. The effect of different inhibitors, inducers and assay parameters such as temperature and pH on enzyme activity were investigated and maximum PPO activity was observed at 30&deg / C, pH 8.0 and when tannic acid was used as an inducer. Copper-chelator salicyl hydroxamic acid (SHAM) and pcoumaric acid, both indicated as inhibitors of tyrosinase and catechol oxidase significantly reduced the activity. For biochemical characterization studies, the enzyme was concentrated by ultrafiltration. To determine type of the enzyme, activity staining after Native-PAGE was carried out. Type of polyphenol oxidase produced by E. peryii and E. sp.A was determined as catechol oxidase by activity staining. However higher activity was observed on hydroquinone (p-diphenol) rather than catechol (o-diphenol). The enzyme obeys Michealis-Menten kinetics with Km and Vmaxvalues being 10.72 mM hydroquinone and 59.44 U/ml for E. peryii and 8.55 mM hydroquinone and 73.72 U/ml for E. sp.A respectively..