Treesearch

Pyrolysis of wood involves the thermal degradation of the wood polymers and the formation of char. Understanding how char forms, particularly, in terms of the nano-structural changes that take place during pyrolysis will inform fire models to ensure fire safety in timber structures. Here, small- and wide-angle x-ray scattering (SAXS/WAXS) based tomography were used to study how thermal degradation changes wood nanostructure across the pyrolysis zone in Douglas-fir. The changes in the aggregation of cellulose elementary fibrils (via SAXS) as well as changes in the cellulose crystallinity...

Eastern subterranean termites, Reticulitermes flavipes (Kollar), are widely distributed across North America where they are exposed to a broad range of environmental conditions. However, mechanisms for overwintering are not well understood. Wisconsin is a unique location to study mechanisms of cold tolerance as it represents the northern boundary for persistent R. flavipes populations. In this study, we evaluated seasonal shifts in cold tolerance using critical thermal minimum (CTmin) and supercooling point (SCP) and examined how these measurements correlate to changes in the microbial...

The mass loss calorimeter provides a robust method for evaluating flammability of very sooty materials such as wood plastic composites as a lower cost and rugged alternative to the reliable and effective cone calorimeter. The high amounts of smoke and carbon monoxide associated with these materials resulted in a much-reduced heat release rate, resulting in incomplete combustion of the diffusion flame, which required modifications to the standards in measuring heat release rate via oxygen consumption or carbon dioxide production or thermopiles. In addition to liquid fuels of ethylene glycol...

Cellulose nanofibrils (CNFs) were investigated as a partial substitution for agar in growth media for wood decay fungi. Radial growth measurements of eight basidiomycete fungi were taken on solid growth media with and without CNFs. Additionally, fungal strain virulence was evaluated using the European CSN Standard EN 113-2 wood decay durability test. The inclusion of CNFs did not significantly affect fungal growth rates on media or in wood decay tests. Rheological evaluations showed that gels from standard malt extract agar were significantly stronger and stiffer than those prepared by a...

Regioselective C6 and C2,C3 carboxylated cellulose nanofibrils (CNFs) have been robustly generated from dissolving pulp, a readily available source of unmodified cellulose, via stoichiometrically optimized 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated and sequential sodium periodate-sodium chlorite (PC) oxidation coupled with high-speed blending. Both regioselectively optimized carboxylated CNF series possess the widest ranges of comparable charges (0.72–1.48 mmol/g for T-CNFs vs. 0.72–1.10 mmol/g for PC-CNFs), but similar ranges of thickness (1.3–2.4 nm for T-CNF, 1.8–2.7 nm...

Rosewood and palisander belonging to Dalbergia (Fabaceae) are some of the most studied tree species in Madagascar. Dalbergia species can be identified based on morphological differences, mainly of flower and fruit, but are practically impossible to tell apart when these structures are missing. To support their sustainable management reliable identification of living Dalbergia is necessary prior to any exploitation. Studies of the vegetative anatomy of Dalbergia are lacking. This is the first report on young stems and leaves in endemic Dalbergia species. We studied 16 Dalbergia species from...

Significant research has been conducted on the development and use of hardwood resources in engineered wood materials and products. This research focused on utilizing undervalued hardwoods for applications that take advantage of their excellent strength properties. Some of the results from this research have been implemented by industry, and additional research has been initiated and is on-going. To bring together industry leaders and scientists, Mississippi State University and the USDA Forest Service, Forest Products Laboratory, led a workshop on this topic in 2023. The objectives of the...

The current study assessed the efficacy of heartwood extracts from Tectona grandis, Dalbergia sissoo, Cedrus deodara, and Pinus roxburghii, combined with linseed oil, as protectants for two non-durable wood species against termites and decay fungi. Stakes measuring 45.7 × 1.9 × 1.9 cm and blocks measuring 12.5 × 3.75 × 2.5 cm of the sapwood of southern pine (Pinus sp.) and cottonwood (Populus sp.) were impregnated via vacuum pressure with individual heartwood species extract, linseed oil, or a combination of both. For comparison, solid heartwood stakes and blocks of the wood species used...

Cross laminated timber (CLT) has become a popular wood composite in large building applications that were previously limited to concrete and steel. To extend service and prevent biological attack, chemical protectants are often applied to wood. Cross laminated timber panels are not typically treated, in part due to a lack of data on efficient and effective methods for treating large panels. There are also limited long term field data regarding the exposure of CLT to biological attack. In this study, commercially prepared CLT panels consisting of either 5-ply Norway spruce or 3-ply southern...

The ability of insecticidal soil drenches or spray-on insecticide/fungicide treatments to protect mass timber elements exposed in a high moisture environment but out of direct soil contact was assessed using a modified AWPA ground proximity test established in 2017. Three-ply Douglas-fir CLT pieces measuring 305 x 355 x 105 mm (L x H x W) were installed at the Harrison Experimental Forest (HEF) (Saucier, Mississippi) in 2017. Test samples were placed in sets of two on bricks approximately 150 mm apart, 75 mm above the soil and covered with ventilated waterproof covers. A total of 20 test...