Treesearch

In this study, cellulose nanocrystals (CNCs) with PEG grafts of various lengths (1 k, 2 k, 5 k, and 10 kDa) were prepared via a polydopamine (PDA) mediated method in the aqueous solution. The prepared CNC-PEGs were further used to reinforce the polyvinyl alcohol (PVA) at the loading of 0, 1, 3, 5, and 7 wt% in order to demonstrate the effects of the PEG length on the properties of the PVA/CNC nanocomposites. PEG surface modification resulted in simultaneous improvements in stiffness and toughness. The graft lengths have noticeable impacts on the properties of composites. The shorter graft...

The aim of this research was to explore the potential of acoustic impact test to evaluate the condition of hardwood logs in regard to internal decay, void, crack and defect ratio using an acoustic signal separation and enhancement algorithm. Longitudinal acoustic signals were obtained from 15 logs of four hardwood species through acoustic impact testing. The defect components were separated from the acoustic response signals and enhanced based on the autoregressive minimum entropy deconvolution (AR-MED) method, and from which the kurtosis was derived and used as the global feature parameter...

Carbon foams have been prepared using Kraft lignin as the solely resource. No catalysts, foaming/blowing agents, surfactants, and/or crosslinking agents are used for the foam preparation. The process includes pressing carbon foam precursors into molds followed by formation of lignin foam through heating and carbonization/graphitization of the lignin derived foams. The resultant lignin carbon foam (LCF) has an open-cell structure with densities ranging from about 0.18 g/cm3 to 0.68 g/cm3. The compressive strengths of LCFs increase with increasing of bulk density, from 7.03 ± 1.25 MPa of...

Optimized wildfire risk reduction strategies are generally not resilient in the event of unanticipated, or very rare events, presenting a hazard in risk assessments which otherwise rely on actuarial, mean-based statistics to characterize risk. This hazard of actuarial approaches to wildfire risk is perhaps particularly evident for infrequent fire regimes such as those in the temperate forests west of the Cascade Range crest in Oregon and Washington, USA (“Westside”), where fire return intervals often exceed 200 years but where fires can be extremely intense and devastating. In this study,...

This study represents a major new collaboration between two State of Washington institutions, the WA Department of Natural Resources (WADNR) and the University of Washington (UW)’s Olympic Natural Resource Center (ONRC), and other key academic and federal research agencies. This multi-agency experiment, called the Type-3 Watershed Experiment, was developed to assess the impacts of current and alternative forest management strategies on a holistic vision of ecosystem wellbeing (with co-equal weighting of both environment and community wellbeing). The core question of the experiment is “Will...

In the past two decades, laurel wilt disease has significantly affected members of the Lauraceae in the southeast United States, causing widespread mortality of native redbay (Persea borbonia (L.) Spreng), and incidence of infections in avocado (Persea americana Mill.), sassafras (Sassafras albidum L.) and swamp bay (Persea palustris [Raf.] Sarg.) (Fraedrich et al., 2008, 2015, Olatinwo, et al. 2019). Laurel wilt is a vascular disease caused by Raffaelea lauricola (T.C. Harr., Fraedrich & Aghayeva), a fungus vectored by a non-native ambrosia beetle Xyleborus glabratus Eichhoff (Fraedrich...

The objectives of this study are to (1) document the extent, severity, and progression of EAB infestation in Arkansas; and (2) reconstruct EAB-induced ash tree mortality patterns as a surrogate for realized spread and infestation progression.

Custom camera traps were positioned at American pika (Ochotona princeps) haypiles in 12 warm, low-elevation locations of eastern California over 5 years and during warm and cold seasons. These camera traps detected 26 mammal and 10 bird species, including 4331 pika events as well as visits by 16 sympatric herbivores and 7 pika predators. Camera traps documented pika occupancy at some sites that had been evaluated from field surveys as extirpated, and they also confirmed field assessments of extirpation at other sites. Individual pikas could be distinguished by scars, size, and pelage...

Evidence suggests the range of Spilogale putorius (Eastern Spotted Skunk) has contracted and its abundance has declined in the past 70 years, leading to conservation concerns. We summarized county records of Eastern Spotted Skunks collected during 2000–2020 to determine the current range and relative abundance of the species. We accumulated 1174 records from 257 counties across its historic range in the United States, with 901 records from 197 counties considered verified. Verified records included museum specimens, photo-documented occurrences, and captures by researchers. We created 2...

This study evaluated the mechanical properties of hybrid (mixed-species) cross-laminated timber (CLT) panels made of low-value sugar maple (Acer saccharum) and white spruce (Picea glauca). The modulus of elasticity (MOE) of the laminations was measured with a nondestructive method. Three-layer hybrid CLT panels with layup combinations of sugar maple–white spruce–sugar maple and white spruce–sugar maple–white spruce were prepared to evaluate the effects of layups on the performance of the CLT samples. The mechanical properties of hybrid CLT panels were evaluated with different layups and...