Thesis (M.S.)--Oregon State University, 1968. / Typescript (photocopy). Includes bibliographical references (leaves 160-171). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1985. / Typescript (photocopy). Includes bibliographical references (leaves 88-94). Also available on the World Wide Web.

The goal of this research was to investigate the influence of selected wood characteristics and composites production parameters on the sorption behavior of wood materials. A better understanding of the sorption behavior of different wood structures and types could be useful in protecting wood against wood deterioration. The differences among tree ring locations within the stem cross-section have not been explained in terms of sorption behavior. The purpose of the first task was to investigate the effect of differences among earlywood, latewood, and tree ring location within the stem crosssection on the water vapor sorption. A loblolly pine (Pinus taeda) tree was cut into earlywood and latewood from the 2nd to 50th tree rings. A sorption kinetics test was conducted from 11% to 89% RH. Results showed that earlywood had higher sorption rates and diffusion coefficients than latewood, while outer tree rings had higher sorption rates and diffusion coefficients than inner tree rings. An understanding of sorption behavior of individual fibers with varying refiner pressure is necessary to better engineer wood fiber-based composites. The second task was to investigate water vapor sorption of refined fiber as affected by steam pressure using small-scale measurements. Juvenile and mature loblolly pine wood was refined at 2 to 18 bar of steam pressure. Fiber properties were determined by Scanning Electron Microscope (SEM), Dynamic Contact Angle (DCA), X-ray Diffraction (XRD), and a water activity meter. A sorption kinetics test was conducted from 11% to 89% RH. Higher rates of sorption were found in juvenile fiber refined under low steam pressure. Higher water activity and lower cystallinity was found at low-steam-pressure-refined fibers. The volume of oriented strandboard (OSB) produced has significantly increased over the last few decades. Wood, resin, and wax play a key role in manufacture and inservice properties. How resin and wax affect the water vapor sorption behavior of resinated and waxed strands remain unclear. The third task was to investigate the effect of processing parameters on the sorption behavior of wood strands under varying environmental conditions. Loblolly pine strands were created with 2 to 4% and 0.5 to 1.5% for resin and wax loading. The resinated strand was pressed with different platen temperatures (120, 160, and 200°C) and compression rates (1.05 and 1.65). A sorption kinetics test was conducted from 11% to 89% RH. Higher resin and wax loading levels resulted in reduced water vapor sorption in early sorption periods. Higher press platen temperatures and compression rates also decreased the sorption properties of resinated loblolly pine strands. Wax loading had more influence on sorption properties than resin loading. Press platen temperatures had more influence on sorption behavior than compression rate.

The growing Wildland Urban Interface community in the Chilhowee Mountain area of Blount County, Tennessee, like many other forested areas in the mountains and hills of East Tennessee, was identified by officials of the Tennessee Division of Forestry as being a high risk area for wildfire. The purpose of this research was to help wildfire managers better understand how to facilitate wildfire protection and mitigation in the Chilhowee Mountain area. A mail survey was sent to the 474 property owners in the communities of Campers Paradise, Happy Valley, and Top of the World. The survey contained 33 questions related to wildfire risk, property characteristics, residential status, experience with wildfire, fire risk perception, and preferences for wildfire reduction strategies. A total of 159 property owners participated in the survey with an overall response rate of 35%. The data were weighted to represent the residential status of the property owners (resident, absentee, and lot owners). Homeowners were more likely to perceive higher risk severity and feel more vulnerable than lot owners and they do not see a wildfire affecting them personally as much as their property or possessions. Perceived risk severity and risk vulnerability was positively correlated with fire risk reduction behaviors for all property owners. The reasons given for not implementing protective measures were (in rank order) vacation home/not living there, cost, age/physical ability, lack of fire fighting equipment/water, time, only so much one can do, and neighbors/others pose risks. Two-thirds of the property owners believe there should be no restriction on construction in areas highly susceptible to wildfire, however, almost three out of four indicated it should be required that home buyers be informed when a house they are considering for purchase is in a fire risk zone. There is a considerable need for agencies to work collaboratively in order to develop effective wildfire protection programs in communities. With a multi-agency team, a strong, coordinated message can be delivered to WUI communities. For wildfire risk mitigation to be effective over the long run, a community must be able to sustain involvement in wildfire risk reduction strategies into the future.

Microstegium vimineum is an annual exotic grass common through the Southeastern United States. Adding M. vimineum to native plant communities may alter future forest composition through inhibiting the growth and influencing recruitment of seedlings into larger size classes, as well as significantly altering vertical structure and community richness, which may influence the distribution of insects. The main objectives of these studies were to 1) establish how different mineral soil and litter disturbances, in combination with various forest canopy coverage, influence the establishment, growth, and spread of M. vimineum, 2) quantify effects of competition between M. vimineum and native hardwood seedlings, and 3) identify the influence of M. vimineum on insect community structure and distribution. As percent canopy cover decreased, M. vimineum mean length and mean number of nodes increased. Also, as soil temperature and soil moisture increased, M. vimineum percent cover increased. Individual seedlings spread further from established populations in both the litter removal and the mineral soil disturbance and litter removal treatments than in the control. The apparent connection between soil disturbance and invasion by M. vimineum provides further impetus for careful planning and use of haul road and skid trails. There was a reduction in A. rubrum and L. tulipifera leaf area as a result of competition with M. vimineum, which was likely due to competition for moisture. Quercus rubra did not display any differences in leaf characteristics as a result of M. vimineum competition. As a result of reductions in growth for A. rubrum and L. tulipifera, competitive impacts imposed by M. vimineum may alter the rate at which these species are recruited into larger size classes. This may change future forest composition, and have ecological and economic consequences. In areas with M. vimineum, there were significantly more insects collected than in areas without M. vimineum. These increases in abundance likely resulted from 2.5 times greater plant cover due to the addition of M. vimineum to the plant communities. However, it should be noted that focusing on a single taxonomic group, such as insects, might not provide an adequate measure of exotic species impacts.

The structure of the actual wood cell wall is very complex and it consists of several layers. Some research has been done to measure the mechanical properties of wood cell wall. For example, the hardness and modulus of wood cell wall was estimated using a nanoindentation test. But the mechanical contribution of wood cell wall is not fully understood and documented in the literature. Understanding the micro mechanical properties of the wood cell wall are paramount because of the potential for applications in cellulose nano-composites research and development. The focus of this research was to investigate the essential of the strength and fracture of wood cell walls by uniaxial micro-compression test. Keranji and loblolly pine were chosen to perform the micro-compression tests. After initial sample preparation by microtoming, a novel method for sample preparation was adopted. The cylindrical shaped micro pillars were milled using a Focused Ion Beam (FIB) while each pillar was milled in a single wood cell wall. The beam voltage of this FIB system was 30 KV. After measuring the dimension of the micropillar through analyzing the SEM images by ImageJ software, the uniaxial compression test on the micro pillar was conducted using a Nano II Indenter system with a 10 micrometers diameter flat tip. The loading rate of 20 nm/s was used to obtain the load-displacement curves. As a result, the yield stress of keranji cell wall was 136.5 MPa and the compression strength was 160 MPa. The yield stress of loblolly pine cell wall was 111.3 MPa and the compression strength was 125 iv MPa. The fracture behavior of wood micropillar confirmed that wood cell wall also is a brittle type of material. KEY WORDS: wood, cell wall, loblolly pine, keranji, focused ion beam (FIB), scanning electron microscopy (SEM), micropillar, uniaxial micro-compression test, fracture behavior.

Stand structure and composition of pyric oak barrens communities were shaped by natural and anthropogenic fire disturbance regimes. Due to fire suppression and land use changes, oak barrens have become rare. In 1963, a study was implemented to evaluate the restorative effects of annual and five year periodic fire on an “oak barrens” hardwood forest at the University of Tennessee Forest Resources Research and Education Center near Tullahoma, TN. The initial study was a randomized block design and analyzed the effects of short-term prescribed fire on hardwood reproduction, herbaceous vegetation, fuel loading, and soil characteristics. Since inception, additional studies of short-term and long-term effects of continual prescribed fire on various components of the ecosystem have been conducted. In 2005, a follow-up study was conducted to evaluate the effects of long-term prescribed fire on stand dynamics, wildlife habitat structure, and small mammal populations. Stand structure and development were documented and treatment differences analyzed. The effects of annual prescribed fire on small mammal abundance and habitat characteristics were compared across treatments at 3 intervals, pre-burn, postburn, and end of season using repeated measures mixed models ANOVA. Predicting small mammal abundance using habitat characteristics was performed using multiple linear regression with stepwise selection. Annual and 5-year periodic burning for 42 years decreased canopy cover and increased vertical and horizontal understory structure. Regeneration mortality was high for both burn treatments and recruitment was unsustainably low. The 5-year periodic treatment was the most structurally diverse and had the highest small mammal abundance and diversity. Three models for small mammal abundance had one temporally-related variable as the most significant: percent cover of vines. Woody height, percent cover of forbs, and percent cover of bunch grasses were also significant variables. Long-term annual and 5-year periodic prescribed fire does not restore oak barrens to historical accounts of the area and is not sustainable. The amount of overstory oak trees continues to decline with continuous burning. A period of time without burning is required for ingrowth to become established in the overstory and be large enough to withstand burning.

There is growing interest in the reforestation of surface mined lands for the production of valuable forest products and creation of quality wildlife habitat. These objectives can be met by planting native woody and herbaceous species on reclaimed surface mines. However, in this region, many of the common ground cover species used to reduce erosion, compete aggressively with tree seedlings, preventing successful establishment. A research project was designed with two main objectives: to investigate the growth and survival of tree seedlings across different herbaceous ground cover treatments, and to identify the relationship between the growth and function of tree seedlings and microsite variables. Five tree species, native to the eastern hardwood forest surrounding the mine site, were planted in 2005. They are: yellow poplar (Liriodendron tulipifera), sugar maple (Acer saccharum), northern red oak (Quercus rubra), eastern redbud (Cercis canadensis), and Virginia pine (Pinus virginiana). Five different ground cover treatments were applied within four replicated planting areas. Two treatments consisted of two different native warm season grass mixes, two were standard reclamation mixes, and one was an unseeded control. Growth and survival, seedling transpiration rate, light measurements, soil respiration, groundcover biomass, and soil chemical properties were measured and analyzed. Survival was significantly different across tree species, with sugar maple having the best overall survival and yellow-poplar the poorest. Seedling survival tended to be greatest within the native warm season grass treatments; however growth rates were variable between all treatments. Seedling survival and growth was related to the amount of herbaceous cover suggesting that tree species react differently to the conditions associated with the surrounding level of herbaceous cover. Moderate ground cover resulted in the best survival, while bare ground or full cover demonstrated the poorest survival rates for northern red oak and eastern redbud. Sugar maple transpiration rate was significantly greater in the moderate (50-75%) cover class during the second growing season. Soil chemical concentrations differed significantly between years, but not between treatments. Soil respiration significantly increased during the two years of this study. The results suggest that moderate herbaceous cover is advantageous for the establishment tree seedlings.

Thesis (Ph. D.)--Oregon State University, 1982. / Typescript (photocopy). Includes bibliographical references (leaves 157-167). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 70-79). Also available on the World Wide Web.