Treesearch

Five full-scale fire experiments were conducted to observe the performance of a two-level apartment-style structure constructed of mass timber. Each level consisted of a one bedroom apartment, an L-shaped corridor, and a stairwell connecting the two levels. One of the primary variables considered in this test series was the amount and location of exposed mass timber. The amount of mass timber surface area protected by gypsum wallboard ranged from 100% to no protection. For each experiment, the fuel load was identical and the fire was initiated in a base cabinet in the kitchen. In the first...

The invention of the Gutenberg printing press in 1440 started a steady increase in demand for paper. Until the mid-1800s, most paper pulp was made by collecting, cleaning, and beating discarded linen and cotton rags. Collection of rags was such a large and organized industry that companies were regulated by the government and workers had unions. Henry Mayhew described a grand banquet of the fraternal order of chiffonniers (rag-pickers).1 As literacy and printing technology improved, demand for paper outstripped supply, and the search for alternative sources of fiber began in earnest. For...

Peroxidases are considered essential agents of lignin degradation by white-rot basidiomycetes. However, low-molecularweight oxidants likely have a primary role in lignin breakdown because many of these fungi delignify wood before its porosity has sufficiently increased for enzymes to infiltrate. It has been proposed that lignin peroxidases (LPs, EC 1.11.1.14) fulfill this role by oxidizing the secreted fungal metabolite veratryl alcohol (VA) to its aryl cation radical (VA ), releasing it to act as a one-electron lignin oxidant within woody plant cell walls. Here, we attached the fluorescent...

There is little published scientific literature on the laboratory or field testing of wood-plastic composites (WPC) against termite attack. Therefore, the objective of this research was to investigate termite resistance (both laboratory and field) of 5 different extruded WPC blends of 50% western pine wood flour (WF) and high-density polyethylene (HDPE), and untreated pine solid wood. The study included two unmodified control WPC blends (one with cut surfaces and one with plastic rich surfaces); one blend with 3% coupling agent (maleated polyethylene, MAPE); one blend with acetylated WF;...

Improved methods are needed to improve the reliability and reporting of Berkovich probe calibrations. Current methods for calibrating machine compliance rely substantially on the subjectivity of the user to choose and exclude from the analysis nanoindentations below a threshold size that are affected by probe tip imperfections or the fused silica surface properties. Furthermore, it can be difficult to identify erroneous experimental data, such as those resulting from dirty or damaged probes. To help overcome these issues in Berkovich probe calibrations, a pre-nanoindentation liftoff...

Heartwood extractives from Tectona grandis were investigated for antitermitic activities against Heterotermes indicola in laboratory experiments. Extractives were removed from wood shavings by soxhlet extraction using an ethanol: toluene (2:1) solvent system. Termite feeding and mortality followed a concentration dependent response. The highest termite mortality occurred at an extractive concentration of 10 mg/ml. The calculated LC50 based on the concentration dependant response was 3.2 mg/ml. Extractives showed high repellency and antifeedant activity against H. indicola. Tests in which...

Within-grade variability in mechanical properties for visually graded lumber has led to increased deployment of nondestructive testing (NDT) methods, even though the relationships between static bending and NDT-predicted values are often highly variable. Dynamic modulus of elasticity (MOEdyn) was measured using two acoustic velocity instruments and one transverse vibration instrument, along with specific gravity, for 819 pieces of visually graded loblolly pine lumber. Static modulus of elasticity (MOE) and bending strength (Fb) were measured via destructive testing. The probability of...

Juvenile wood (core wood) in softwood species is typically characterized as being less dimensionally stable and having lower mechanical properties than mature wood. Determining the age of transition between juvenile wood and mature wood is important when making judgments about utilization options for naturally occurring stands of trees in the intermountain west region of the United States. Lodgepole pine (Pinus contorta Dougl. ex. Loud.) trees were harvested from four different sites in the US Inland Northwest to include site variations that affect growth, such as elevation, precipitation,...

Heartwood extract from white mulberry (Morus alba L.) (Rosales: Moraceae) were investigated for antitermitic activity against Reticulitermes favipes (Kollar) (Blattodea: Rhinotermitidae) in laboratory experiments. An ethanol:toluene (2:1) solvent system was used to remove extract from heartwood shavings. A concentration-dependent feeding response and mortality were observed for termites exposed to a concentration series range of 1.25 to 10 mg/ml of extract based on their dry weight. Results showed that maximum termite mortality occurred at 10 mg/ml. Based on the concentration series data,...

AbstractWith the world’s increasing focus on sustainability in the construction sector through green building systems, the U.S. Department of Agriculture (USDA) has been ac-tively engaged in green building advocacy in the United States through USDA Tall Wood Building competitions and follow-up research on use of mass timber for nonresi-dential buildings. The USDA Forest Service, Forest Prod-uct Laboratory (FPL) funded the study of environmental performance of the pioneer mass timber building (the John W. Olver Design Building) built at University of Massachu-setts Amherst in 2016. The...