The Lower Coastal Plain of the southeastern United States is a major wood producing region. The region is characterized by a combination of nearly-level topography, poorly-drained soils, and high rainfall, which results in a perched water table in some soils that inundates the surface several times each year. Harvesting timber under wet site conditions often results in extensive soil compaction, rutting, soil displacement, and waterlogging. Forest managers are concerned that these visually-displeasing soil disturbances may cause site damage and reduced productivity. These concerns were addressed in an operational-scale field experiment conducted in South Carolina. The objectives of this experiment were to determine: (i) if soil disturbance changes key soil properties and processes; (ii) if soil disturbance reduces loblolly pine productivity; and, (iii) if disturbance can be mitigated with site preparation practices? Three 20-ha, 20-yr-old loblolly pine (Pinus taeda L.) plantations were harvested under wet and dry conditions to create a broad gradient in soil disturbance. Within each harvested plantation, a subset of 3-ha plots were site prepared by either bedding, or mole-plowing plus bedding, then all sites were established as 3rd -rotation pine plantations. Prior to site preparation, each plot was classified and mapped using a 5 by 5 soil disturbance (none to churned) by organic debris (none to slash piles) classification matrix. Within each plot, data were collected on several soil physical, chemical, and biological properties over a 2-yr period following site preparation. Key soil properties were integrated into a Soil Quality Index (SQI) and compared to aboveground productivity of 2-yr-old loblolly pine trees growing on closely-spaced (30 by 30 cm) bioassay plots planted across the gradient of soil disturbance. The soil physical properties were used to determine the least limiting water range (LLWR), the range in soil water content within which root growth is not limited. Soil compaction and deep rutting reduced the LLWR. Retention of logging slash improved the LLWR for compacted and rutted soils. Site preparation improved the quality of the soil physical environment across all levels of soil disturbance. Soil disturbance had no effect on soil chemical or biological properties as evidenced by no change in soil pH, ECEC, base saturation, available P, or net N mineralization with disturbance. The base saturation exceeded 80 % on all sites, with Ca saturation controlling soil pH. The high base saturation buffered any redox-induced changes in soil chemistry that would have resulted from disturbance. The results showed that high fertility is an important mechanism for buffering the potentially-negative effects of soil disturbance on the soil nutritional environment. Site preparation changed soil chemical properties, but the changes were probably associated with tillage effects on organic matter and clay content, not redox processes. The SQI showed that surface soil compaction and deep rutting reduced soil quality, mainly by decreasing the LLWR and aeration depth. Site preparation mitigated the effects of most disturbances on soil quality, evidenced by similar aboveground biomass production among soil disturbance classes after bedding. A regression model was developed for predicting aboveground biomass production as a function of SQI. SQI explained 73 % of the variation in aboveground biomass production. The regression model showed that compression tracks and rutting decreased aboveground biomass production compared to undisturbed soils. The long-term effect of these disturbances on productivity will depend on natural soil recovery processes. However, these early results suggest that compaction and rutting should be minimized on similar sites, especially if sites will not be bedded before reforestation. The mole-plow / bedding treatment increased aboveground biomass production, indicating that this experimental treatment may be a viable practice for enhancing productivity. / Ph. D.

A stochastic framework to simulate the process of initiation, diameter growth, death and self-pruning of branches in loblolly pine (Pinus taeda L.) trees was developed. A data set was obtained from a destructive sampling of whorl sections from 34 trees growing under different initial spacing. Data from dissected branches were used to develop a model for representing knot shape, which assumed that the live portion of a knot can be modeled by a one-parameter equation and the dead portion by assuming a cylindrical shape. For the developed knot model analytical expressions were derived for estimating the volume of knots (live/dead portions) for three types of branch conditions on simulated trees: (i) live branches, (ii) non-occluded dead branches, and (iii) occluded dead branches. This model was intended to recover information on knots shape and volume during the simulation process of branch dynamics. Three different components were modeled and hierarchically connected: whorl, branches and knots. For each new growing season, whorls and branches are assigned stochastically along and around the stem. Thereafter, branch diameter growth is predicted as function of relative location within the live crown and stem growth. Using a taper equation, the spatial location (X,Y,Z) of both live and dead portion of simulated knots is maintained in order to create a 3D representation of the internal stem structure. At the end of the projection period information on (i) vertical trend of branch diameter and location along and around the stem, (ii) volume of knots, and (iii) spatial location, size and type (live and dead) of knots can be obtained. The proposed branch model was linked to the individual-tree growth and yield model PTAEDA3.1 to evaluate the effect of initial spacing and thinning intensity on branch growth in sawtimber trees. The use of the dynamic branch model permitted generation of additional information on sawlog quality under different management regimes. The arithmetic mean diameter of the largest four branches, one from each radial quadrant of the log (i.e. Branch Index, BI) and the number of whorls per log were considered as indicators of sawlog quality. The developed framework makes it possible to include additional wood properties in the simulation system, allowing linkage with industrial conversion processes (e.g. sawing simulation). This integrated modeling system should promote further research to obtain necessary data on crown and branch dynamics to validate the overall performance of the proposed branch model and to improve its components. / Ph. D.

Informed forest management requires accurate, up-to-date information. Ground-based forest inventory is commonly conducted to generate estimates of forest characteristics with a predetermined level of statistical confidence. As the importance of monitoring forest resources has increased, budgetary and logistical constraints often limit the resources needed for precise estimates. In this research, the incorporation of ancillary information in planted loblolly pine (Pinus taeda L.) forest inventory was investigated. Additionally, a simulation study using synthetic populations provided the basis for investigating the effects of plot and stand-level inventory aggregations on predictions and projections of future forest conditions. Forest regeneration surveys are important for assessing conditions immediately after plantation establishment. An unmanned aircraft system was evaluated for its ability to capture imagery that could be used to automate seedling counting using two computer vision approaches. The imagery was found to be unreliable for consistent detection in the conditions evaluated. Following establishment, conditions are assessed throughout the lifespan of forest plantations. Using small area estimation (SAE) methods, the incorporation of light detection and ranging (lidar) and thinning status improved the precision of inventory estimates compared with ground data alone. Further investigation found that reduced density lidar point clouds and lower resolution elevation models could be used to generate estimates with similar increases in precision. Individual tree detection estimates of stand density were found to provide minimal improvements in estimation precision when incorporated into the SAE models. Plot and stand level inventory aggregations were found to provide similar estimates of future conditions in simulated stands without high levels of spatial heterogeneity. Significant differences were noted when spatial heterogeneity was high. Model form was found to have a more significant effect on the observed differences than plot size or thinning status. The results of this research are of interest to forest managers who regularly conduct forest inventories and generate estimates of future stand conditions. The incorporation of auxiliary data in mid-rotation stands using SAE techniques improved estimate precision in most cases. Further, guidance on strategies for using this information for predicting future conditions is provided. / Doctor of Philosophy / Informed forest management requires accurate, up-to-date information. Groundbased sampling (inventory) is commonly used to generate estimates of forest characteristics such as total wood volume, stem density per unit area, heights, and regeneration survival. As the importance of assessing forest resources has increased, resources are often not available to conduct proper assessments. In this research, the incorporation of ancillary information in planted loblolly pine (Pinus taeda L.) forest inventory was investigated. Additionally, a simulation study investigated the effects of two forest inventory data aggregation methods on predictions and projections of future forest conditions. Forest regeneration surveys are important for assessing conditions immediately after tree planting. An unmanned aircraft system was evaluated for its ability to capture imagery that could be used to automate seedling counting. The imagery was found to be unreliable for use in accurately detecting seedlings in the conditions evaluated. Following establishment, forest conditions are assessed at additional points in forest development. Using a class of statistical estimators known as small-area estimation, a combination of ground and light detection and ranging data generated more confident estimates of forest conditions. Further investigation found that more coarse ancillary information can be used with similar confidence in the conditions evaluated. Forest inventory data are used to generate estimates of future conditions needed for management decisions. The final component of this research found that there are significant differences between two inventory data aggregation strategies when forest conditions are highly spatially variable. The results of this research are of interest to forest managers who regularly assess forest resources with inventories and models. The incorporation of ancillary information has potential to enhance forest resource assessments. Further, managers have guidance on strategies for using this information for estimating future conditions.

The controversy regarding commercial thinning continues to intensify as pine plantation acreage in the south increases. This controversy has caused industrial and nonindustrial landowners to re-examine the economic returns from their plantation investments. This study was undertaken to develop investment guidelines for the management of loblolly pine plantations. Computer simulation was used to evaluate the effect on present value that four future price/market scenarios, three management regimes, and three mechanized thinning systems can have on current thinning investments. When the economic returns from thinning are compared with a no-thin management regime, simulation results indicate that long-term investment advantages favor thinning only slightly, regardless of the future price/market scenario assumed. This slight difference suggests that individual forest product companies may find other reasons such as wood flow, tax advantages, and future product requirements of their manufacturing facilities to be overriding factors for engaging in commercial thinning. Generally, short-run cost and production differences between thinning systems are more significant than the long-term investment effects. Consequently, the type of mechanized thinning system employed has a negligible impact on the total investment. / Ph. D.

Thirty-six eight-year-old white pine (Pinus strobus L.) trees were used to identify minesoil, plant moisture, and foliar nutrient properties influencing white pine growth on reclaimed mine sites in southwest Virginia. PRESSAll (SAS Views, 1984) was used to determine relationships between soil properties and growth, soil properties and functional environmental factors (plant moisture stress and foliar nutrients), and between functional environmental factors and growth. PRediction Error Sum of Squares (PRESS), Mean Square Error (MSE), and Multiple Correlation Coefficient (R²) were used as criteria for variable selection and model validation. Rooting-volume index, the reciprocal of the electrical conductivity (EC), and extractable P in the soil-sized fraction of the minesoils were the best validated variables, predicting tree heights with the smallest amount of unit error (APRESS of 0.86 m) and accounting for the highest R² ( R² = 53.06%). The depth of the rooting volume had the greatest effect on 2 early growth (R² = 7 .91%), but variation in the last four years of height growth appeared to be a function primarily of rooting volume (R² = 51.40, p < 0.0001). Relationships between soil properties and 2 functional environmental factors varied widely (R² = 0.00-27 .50%). Plant moisture stress was most highly associated with the volume of the soil-sized fraction (R² = 13.6%), foliar phosphorus with soil pH (R² = 22.5%), and foliar cations with anaerobic-mineralizable nitrogen (R² = 0.00-27 .5%). The relationship between functional environmental factors and growth was uniformly weak (R² = 0.00-14.97%). Plant moisture stress was consistently related to overall height and its increment over the last four years, but foliar nutrients were erratically related to growth. No significant relationships between other functional environmental factors and growth were detected. Minesoil indices for individual trees ranged from 47-147 (base age 50). The depth of minesoil for site index 80 (average for Southern Appalachia) was 40 cm. / M. For.

The pine engraver beetles (~ spp.:Coleoptera:Scolytidae) may be serious pests depending on certain prerequisite conditions. In their secondary or "normal" role they breed in slash and damaged, dying, and dead trees. The broods emerging from these sources normally attack similar material. When such material is scarce due to cessation of cutting operations in mid-season or when conditions are especially favorable for brood development, an excess of beetles is often produced which, due to the lack of more suitable material, attack healthy trees. Repeated attacks cause these trees to succumb and die. When normally healthy trees are weakened by fire, flood, defoliation, drought, stagnation, etc., then they become more acceptable host material for successful engraver attacks. When the production of a very large number of beetles in "normal" breeding material coincides with physiological stress in "healthy" trees, then population explosions can occur. When large numbers of beetles and low host vigor do not coincide, spot kills cornnon1y occur. According to Thatcher (32), spot kills, although not conspicuous, add up to large volumes of timber loss each year. / Ph. D.

To prevent the buildup of epidemic level mountain pine beetle populations, conditions of the stand environment they inhabit must be altered. Silvicultural treatment is the most effective means for doing this. Preventative treatments work best when applied while mountain pine beetle populations are still at the endemic population level. Therefore, information necessary for making decisions concerning mountain pine beetle populations in lodgepole pine stands needs to be included in the initial silvicultural prescription planning process, at a time before beetle populations reach outbreak numbers. In this dissertation, several quantitative descriptions of the mountain pine beetle/lodgepole pine relationship were investigated. Models were developed to 1) describe the temperature-dependent development of six mountain pine beetle life stages and 2) describe the amount of loss a stand could sustain if an epidemic level population were to occur in the stand. Concepts of mountain pine beetle risk rating were also discussed. These models and additional information pertaining to the mountain pine beetle/lodgepole pine relationship were incorporated into a knowledge-based system, the MPB Advisory System. This system was designed to help U.S. Forest Service silviculturists include decisions concerning mountain pine beetle populations in the stand management process. / Ph. D.

The objectives for this research were to determine: 1) the rate of Micromax which will produce maximum growth of pin oak (Quercus palustris Munchh.), a landscape tree which has shown a previous growth response to the addition of Micromax at the manufacturer's recommended rate, 2) which micronutrient(s) is most associated with maximum growth, and 3) the rate of Cu, Fe, Mn, and Zn required to produce maximum growth of Quercus palustris. Q. palustris seedlings were container-grown in pine bark amended with the following rates of Micromax: 0, 0.15, 0.3, 0.6, 0.9, 1.8, or 2.7 kg(m-3 in 2000, 2001, and 2002. For all three years, the maximum growth was obtained at rates near the manufacturer's recommended rate of 0.9 kg(m-3. A micronutrient mix was formulated by increasing the levels of Zn, Mn, Fe, and Cu individually while holding the other micronutrients constant based on the grams of each micronutrient contained in Micromax at 0, 0.15, 0.3, 0.6, 0.9, 1.8, or 2.7 kg(m-3 for 2001 and 0, 0.45, 0.9, or 1.8 kg(m-3 for 2002. In addition, Cu, Fe, Mn, and Zn were also applied alone to pine bark at rates of 0, 0.45, 0.9, or 1.8 kg(m-3 without the addition of any other micronutrients. Holding all other micronutrients constant and increasing the rate of one micronutrient did not increase growth. However, when Cu, Fe, Mn, or Zn was added to pine bark alone at increasing rates, growth increased. For Cu and Zn, the growth increased was linear suggesting that a higher rate of Cu and Zn than that provided by Micromax at the manufacturer's recommended rate might be advantageous. / Master of Science

The effects of cultural treatments including ectomycorrhizal inoculation, chemical weed control, and slow-release fertilization on survival, growth, ectomycorrhizal colonization, and foliar nutrient levels of container-grown white (Pinus strobus L.), loblolly (P. taeda L.), and Virginia pine (P. virginiana Mill.) seedlings were studied on a recontoured and a fiat bench strip-mine site in Southwestern Virginia. One-half of the seedlings was inoculated with Pisolithus tinctorius (Pers.) Coker and Couch (Pt). A 21 g Agriform starter tablet was placed in the soil at a depth of 10 cm within 10-15 cm of each seedling in one-half of the plots at planting. Glyphosate was applied to one-half of each plot prior to planting and again later in the growing season. First year survival was not different between sites and was not significantly affected by the cultural treatments. Abundant precipitation and high soil moisture levels throughout the initial growing season may have accounted for the excellent first year survival. The combination of chemical weed control and fertilization significantly increased the growth of all three species. Pt inoculation enhanced seedling growth to some extent but high amounts of natural ectomycorrhizal colonization masked some of the effects of Pt. Levels of foliar nitrogen closely reflected the effects of each treatment on seedling growth, indicating that it was the growth-limiting nutrient for pine seedlings on these strip-mined sites. / Master of Science

At the Fort Bragg Military Installation, an army base in North Carolina, the habitat associations for the breeding bird species and the effects of the current prescribed fire program on the avifauna are virtually unknown. Fort Bragg encompasses one of the largest, fire-dependent longleaf pine systems existing today and is a mosaic of forested habitats. I used bird count data collected during 1994-1997 at 50-m fixed radius point count stations to examine bird species-habitat relationships in relation to fire treatment (i.e., fire intense longleaf pine woodlands versus fire suppressed mixed pine-hardwood and hardwood forests) and a riparian-upland habitat gradient, and at multiple spatial scales (i.e., the microhabitat and landscape). I used two-way factorial analyses to test for the effects of fire treatment and the riparian-upland habitat gradient on total bird abundance, species richness, and species relative abundance. To examine species-habitat associations at multiple spatial scales, I measured vegetation characteristics at a 50-m radius microhabitat scale, and I quantified landscape structural attributes at a 300-m to 1500-m radius landscape scale using a GIS database and the spatial analysis program FRAGSTATS. I then used logistic regression to determine which microhabitat and landscape variables were associated with the probability of occurrence for each species and which spatial scale was of greater relative importance to a species' occurrence. Finally, I tested logistic regression (LR) models and multiple linear regression (MLR) models, specific to the microhabitat scale, with independent data to evaluate their usefulness at predicting the occurrence and relative abundance for several breeding bird species. Total bird abundance did not vary across fire treatment and species richness may be only slightly greater in fire suppressed habitats, even though this habitat offered greater structural complexity than the park-like longleaf pine, fire intense habitats. Both total bird abundance and species richness were highest within the riparian habitat of streamhead pocosins, which offered distinctive vegetative characteristics otherwise lacking in this landscape. The fire treatment and riparian-upland habitat gradient also were greatly associated with the relative abundance of many species. Four bird species assemblages were defined based on the relative abundance patterns across fire treatments and the riparian-upland gradient: longleaf pine, fire suppressed, drain (i.e., riparian habitat), and generalist assemblages. Continued longleaf pine restoration using growing season prescribed fire likely will cause a decline in species of the fire suppressed assemblage in mixed pine-hardwood and hardwood forests, including many Neotropical migrant songbirds, but will greatly benefit members of the longleaf pine assemblage, such as the Red-cockaded Woodpecker, Brown-headed Nuthatch, Prairie Warbler, and Bachman's Sparrow. Breeding bird distributions in this fire-influenced, forest-dominated system were associated with attributes at both microhabitat and landscape spatial scales, though microhabitat attributes generally were of greater importance for the occurrence of most species. Microhabitat variation associated with the fire management gradient (intensely burned habitat versus fire suppressed habitat) and the riparian-upland gradient were the most frequent predictors in the species-habitat models. These results are similar to other studies documenting that microhabitat features were more influential than landscape features for birds in a naturally patchy or forest-dominated landscape. The microhabitat LR (probability of occurrence) models performed best in presence/absence classification when tested with the same data used for model development (cross-validation tests), and the LR and MLR (relative abundance) models performed better for an independent two-year data set compared to an independent one-year data set (validation tests). Although most MLR models were not significantly biased when tested with an independent two-year data set, these models had relatively low precision, suggesting they can be used to predict species relative abundance across a large area but they may not be sensitive to changes in abundance at individual count stations. These model validation results suggest that modeling species occurrence, rather than both occurrence and relative abundance, would have been sufficient to describe general species-habitat associations and to produce reliable, predictive models sensitive to changes in microhabitat structure and composition. / Master of Science