Over the past few decades, university level US Forestry and Wood Science and Technology programs have faced declining enrollment. As a result, the seeming disinterest of younger generations has impacted employment in these sectors. In an attempt to bridge the communication gap among colleges/industries, this study was created to attract the interest and maintain the enthusiasm of new generations of professionals and currently enrolled college students in the United States. In September 2021, an online survey was created and distributed to over 1500 alumni and students and received 1,495 usable surveys. Analysis performed on the resultant data included descriptive statistics and chi-square calculations. Although the study results indicate that the current generation of students and professionals appear to have basic knowledge surrounding the forestry and wood products/science industries, they showed a lack of awareness of the available careers linked to the sector.

This work is made up of three parts. Part one looks to establish design values for two types of three ply access mats from the U.S. South and Midwest. The mats were subject to 3 point bending tests to determine strength and stiffness values. Values for MOE (Modulus of Elasticity) and MOR (Modulus of Rupture) are reported by region and mat design. Part two tested five species groups of hardwoods for wear resistance and hardness. These species groups include white oak, red oak, ash, sweetgum and hickory. These tests for wear were performed on a Navy-Type Wear Tester according to ASTM D2394-17. Hardness specimens were tested with the Janka method according to ASTM D143-14. The third and final part looks at the impact of thermomechanical densification on rate of wear in five species groups of hardwood. The species groups were white oak, red oak, ash, sweetgum and hickory. Samples were pressed at 1000psi at temperature of 350 degrees Fahrenheit, in order to plasticize the wood and densify it at the same time. These samples were then tested on the Navy-Type Wear Tester to determine whether densification had an impact on wear resistance.

Biomaterials such as wood and bamboo are in high demand as a building material with the push for building with green technology. The wood product industry accounts for approximately 4% of the total U.S. manufacturing GDP (Gross Domestic Product), which is more than $100 billion. The industry supports over 752,000 full-time equivalent jobs, most of which are in rural areas where employment opportunities are limited. The estimated global market value of bamboo is estimated to be $60 billion annually. This research will explore the use of wood and bamboo in different end use products. The objectives of this research will 1) evaluate the behavior of two single bolt connections in the post-to-rail joint in a hardwood stairway system; 2) the potential of post-treating pre-fabricated cross-laminated timber (CLT) panels with two different copper based preservative treatments; and 3) estimated design values for a commercially sourced bolt laminated bamboo industrial mat. To accomplish these objectives, this dissertation is divided into five sections: 1) Introduction, 2) Structural performance of the post-to-rail connectors in a hardwood stairway handrail, 3) Development of preservative-treated cross-laminated timber: effects of panel layup and thickness on bonding performance and durability when treated with copper-azole (CA-C) and micronized copper-azole (MCA), 4) Strength and stiffness of 3-ply industrial bamboo matting, 5) Conclusion.

Softwood is more in demand than hardwood because it is used primarily in the US's largest wood-consuming industry, construction, resulting in increased importation of softwood annually to meet this demand. Hardwood, used for non-structural purposes like furniture and interior designs, is more abundant in US forests. However, some hardwood species are underutilized and undervalued. Cross-laminated timber (CLT) has increased the demand for softwood. A study evaluated the mechanical and physical properties of three underutilized hardwood species (321 yellow poplar, 393 sweetgum, and 262 red oak specimens) for CLT industrial mat manufacturing. The results showed that red oak had a higher density than southern yellow pine, and all species had an average modulus of elasticity greater than the CLT lumber requirement. The study confirmed the viability of these underutilized hardwoods for CLT fabrication, suggesting they could be a suitable substitute for softwood in CLT manufacturing.

Understanding how different processing variables influence wood welded bonds is vital if the technique will ever be used to create engineered lumber without using adhesives. A variation of vibration welding, wood welding uses pressure and friction to bond materials together. During welding, heat causes a softening in the wood, a naturally occurring composite material. This softening leads to fiber entanglement and a bond forms upon cooling. The goal of this research was to investigate several processing aspects of the wood welding procedure. A prototype wood welding machine, designed and fabricated from the ground up, was used to investigate the effects of various welding parameters using birch wood. Wood welds were evaluated on the basis of bond coverage and ultimate shear strength. Four experiments were performed: welding frequency and duration interaction, grain orientation effects, alternative welding completion metrics, and strength development over time. During the wood welding process, three distinct phenomena were repeatedly observed: smoke creation, welding residue formation, and an audible pitch change. The presence of each was recorded for every wood welded specimen and used later in additional data analysis. Investigating each of the welding phenomena was done in an attempt to better characterize when fusion was achieved at the weld interface. ImageTool, an image analysis software package, was used to investigate and quantify the often irregular bonds exposed after shear fracture. The results of the various welding variables were analyzed on the basis of shear strength and bond uniformity. From the birch samples, it was shown that better bonds result from lower welding frequencies and longer welding durations. The grain orientation analysis demonstrated that welding orientation marginally affects the average shear strength of the wood weld. The data from the alternative welding metrics suggests that welding time is not a quality indicator of welding completion (bond coverage). The strength development trials confirmed previous research; wood welds obtain most of their strength in a relatively short period of time. Douglas fir and poplar both proved to be weldable for the first time, but they were sufficiently weaker than birch. When welding was attempted with Douglas fir under similar pressures used for birch, Douglas fir samples would commonly “washboard.” With reduced welding pressure, Douglas fir formed wood welds more easily.

Wood is a renewable resource and versatile material used in tasks ranging from tools and furniture to advanced engineering structures. Although wood is light, mechanically robust, environmentally friendly, and abundant, some inherent properties of wood, such as degradation due to moisture and UV radiation from sunlight, are less desirable for extended service life and dimensional stability. In this dissertation, a novel surface modification of wood is explored by depositing nano-sized titania particles on wood veneers and cross-laminated timber (CLT) blocks by liquid-precursor flame spray pyrolysis to confer reversible wettability switching and enhanced durability to UV irradiation. The reaction between a flame source and a titanium precursor in isopropyl alcohol under controlled air pressure created a micrometer-scale thin TiO2 coating on wood that turns the treated wood superhydrophobic with a water contact angle (WCA) of >=150°. Morphological studies suggest the coating is comprised of sub-100 nm TiO2 individual and aggregated particles, creating a very porous microstructure. The coating consists of TiO2 rich in the anatase phase (>60%) with an average crystal size of 18 and 32 nm for the anatase and rutile phases, respectively. The wettability switching characteristics of the surface of TiO2-wood veneers from superhydrophobicity to superhydrophilicity (WCA ~0°) and again back to superhydrophobicity are examined through UV exposure (0.0032 W/m2), WCA measurements, and vacuum drying at ~0.14 mbar. The color and gloss spectrometry results of the TiO2-treated CLT samples indicate that the coating offered better resistance to discoloration and gloss change than the uncoated samples during the 8-week accelerated weathering conditions. The data shows that the FSP-treated CLT samples were more than two times more effective in preventing discoloration and changes in natural luster, as evidenced by the significant differences in L*, a*, b*, and gloss values. Moreover, the FSP treatment might have played a role in preventing weathering defects, such as splits and cracks. In addition, the FSP-treated CLT specimens were able to reduce variability in the samples more effectively than the control group. Overall, the findings of the study indicate that liquid-precursor FSP has the potential to serve as a facile, economically viable, and less energy-intensive approach to modify wooden surfaces for improved hydrophobicity, as well as to provide shielding against the deteriorating impacts of UV radiation and moisture exposure. Keywords: wood modification, flame spray pyrolysis, titania coating, superhydrophobic coating, particle deposition, wettability switching

The flexural and tensile properties of visually graded southern yellow pine lumber were modeled. Longitudinal and transverse vibration techniques and proof-loading bending tests were used to assess the flexural and tensile properties of southern pine lumber. The properties evaluated were dynamic modulus of elasticity (dMOE), static modulus of elasticity (Eb), tension modulus of elasticity (Et), and ultimate tensile stress (UTS). The tensile properties were evaluated in the direction parallel to the grain. This study presents the results of tests conducted on No. 2 2 × 6 and 2 × 10 southern pine lumber of two different lengths (14 ft. and 16 ft.). The results of the analysis show that nondestructive testing techniques are excellent to assess Et and Eb. Moderate relationships were found between dMOE and UTS and between Eb and UTS. Improvements in the prediction of UTS were done with the inclusion of additional parameters into the model. The combination of dMOE, density, and frequency domain area (FDA) generated the highest coefficient of determination for UTS. The distributions of flexural and tensile properties were analyzed for the goodness of fit. Normal distribution was found for Eb data whereas the lognormal distribution was the best fit for the tensile properties.

Renewable lignocellulosic materials are promising green plastic alternatives to fossil fuel-based plastics. However, the hydrophilic nature and poor water resistance of lignocellulosic materials have hindered their practical applications. This study reports a facile metal-ion-modification (MIM) route, swelling with aqueous metal ion solutions, and drying to convert conventional hydrophilic paper and wood pulp into biodegradable hydrophobic paper and tableware without the addition of hydrophobic sizing chemicals/materials. Metal ions such as Fe3+ and Zr4+ can coordinate with pulp fibers’ polar groups (i.e., O.H., C=O, and COOH) that induce self-assembly of their surface fibrillated “hairy” cellulose nanofibrils to form a more compact structure with fewer available O.H. groups for water sorption. The formation of coordination bonds with polar groups (i.e., O.H., C=O, and COOH) decreases the surface energy of pulp fibers and increases their hydrophobicity and water resistance. Only ~3 mg of metal ions is needed to induce the wettability transition in 1 g of kraft pulp, resulting in hydrophobic paper and tableware with water contact angles (WCAs) of 120-140° and displayed wet tensile strengths of up to 9.5 MPa, and low water absorbency, which were comparable to synthetic polymer films. This MIM technique can be integrated into the existing paper-making process for the scalable production of hydrophobic papers and tableware, providing an alternative route for developing sustainable and biodegradable plastic counterparts. The MIM-induced lignocellulose hydrophobization mechanisms were elucidated using X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared spectroscopy (FT-IR), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and density functional theory (DFT). Furthermore, this MIM technique was also evaluated for its applicability in wood treatment. The treatment effectively tunes the wood surface from hydrophilic to hydrophobic, enhancing its water resistance. The MIM treatment significantly improved the dimensional stability of SYP, red oak, and poplar. For example, the Fe3+ treatment reduced the tangential swelling of SYP, poplar, and red oak by 57%, 50%, and 40%, respectively. Overall, this eco-friendly and facile MIM method holds promise for developing sustainable and biodegradable alternatives to conventional plastics, contributing to a more environmentally friendly future.

The current method for estimating wood failure is highly subjective. Various techniques have been proposed to improve the current protocol, but none have succeeded. This research aims to use deep learning/semantic segmentation using SegNet architecture to estimate wood failure in four types of three-ply plywood from mechanical shear strength specimens. We trained and tested our approach on custom and commercial plywood with bio-based and phenol-formaldehyde adhesives. Shear specimens were prepared and tested. Photographs of 255 shear bonded areas were taken. Forty photographs were used to solicit visual estimates from five human evaluators, and the remaining photographs were used to train the machine learning models. Twelve models were trained with the combination of four image sizes and three dataset splits. In comparison to visual estimates, the model trained on 512 × 512 image size with 90/10 dataset split had a mean absolute error (MAE) of 6%, which was the best among the literature.

As madeiras utilizadas para produção de polpa celulósica podem ser divididas em dois grupos em função da fibra: folhosas (fibra curta) e coníferas (fibra longas), as espécies de folhosas são destinadas especialmente a papéis de escrita e impressão. As principais espécies de folhosas utilizadas para produção de polpa de fibra curta em outros países são o Eucalyptus globulus (Península Ibérica e Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canadá), Acacia mangium, Acacia crassicarpa (Indonésia). Este projeto tem por objetivo: avaliar e comparar o desempenho de madeiras utilizadas mundialmente para produção de polpa celulósica de fibra curta considerando parâmetros de qualidade da madeira tais como composição química, densidade básica, características anatômicas da madeira; com objetivo de fornecer informações estratégicas para o setor nacional de celulose e papel, visando o conhecimento e posicionamento em competitividade destas madeiras no mercado mundial. Para a realização deste trabalho foram coletadas 5 árvores de cada espécie as quais foram utilizados cavacos cortados manualmente obtidos de discos; com relação à madeira foram determinadas densidade básica, composição química e dimensões de fibras. Os resultados foram analisados estatisticamente sendo comparadas as diferentes espécies referentes à qualidade da madeira. / Wood used for pulp production may be divided in two major groups regarding fiber function: hardwood (short fiber) and softwood (long fibers). Hardwood species are mainly designated to writing and printing papers. Hardwood principal species used for production of short fiber pulp in other countries are Eucalyptus globulus (Iberian Peninsula and Chile), Eucalyptus nitens (Chile), Populus tremuloides (Canada), Acacia mangium and Acacia crassicarpa (Indonesia). This study aimed to evaluate and compare the performance of the main woods used worldwide for short fiber pulp production regarding wood quality parameters such as chemical composition, basic density and wood anatomical properties, in order to provide strategic information for national pulp and paper industry, aiming the knowledge and competitiveness of these woods at worldwide market. To accomplish this study, 5 trees from each species were collected and wood chips were manually cut. In relation to the wood, basic density, chemical composition and fiber lengths were determined. The results were statistically analyzed and the different species were compared regarding wood quality.