Treesearch

While there are a handful of universally toxic woods (e.g., yew), for most woods and woodworkers, toxicity is a complex but fundamentally individual matter. Some people will react to minor exposures to a given wood, while others can work that species with no obvious effect. What matters most is how we are exposed to those chemicals, how our bodies can react, and how we can protect against exposure to those chemicals.

In May, construction data was weak, but improvements were noted. Total starts; total, single-family, and multi-family permits; and new single-family sales increased on a month-over-month basis. On a year-over-year basis, most of the data indicated declines, except for total starts, new single-family sales, and total private residential construction spending. The impact of the Covid-19 virus is still evident in this month’s data.

In June, housing starts and new house sales were reassuring, as housing was a bright spot for the U.S. economy, albeit a subdued one. Total, single-, and multi-family starts; total and single-family permits; total and single-family completions; and new and existing house sales were positive on a month-over-month basis. Housing under construction and completions were the only subsectors registering positive data year-over-year. The majority of housing subsector data were negative. The effect of the Covid-19 virus is still evident in June’s data.

With this guide we want to provide an overview of the current best-practice methods used to analyse data derived from different wood identification methods, while presenting their respective strengths and limitations. We give advice on data analysis, from the development of reference data, through to the verification of identity and provenance of unknown samples against the reference database. We end with an expert view on combining methods for wood identification and discuss how timber identification possibilities could expand in the future.

Forests, estimated to contain two thirds of the world’s biodiversity, face existential threats due to illegal logging and land conversion. Efforts to combat illegal logging and to support sustainable value chains are hampered by a critical lack of affordable and scalable technologies for field-level inspection of wood and wood products. To meet this need we present the XyloTron, a complete, self-contained, multi-illumination, field-deployable, open-source platform for field imaging and identification of forest products at the macroscopic scale. The XyloTron platform integrates an imaging...

The use of less-toxic solvents is highly desirable for biopolymer processing and applications to meet sustainability while alleviating environmental burdens. In this study, chitin was propionylated to improve its solubility. The highly propionylated chitin exhibited considerably improved solubility (up to 96%) in a binary ethanol/water solution as compared to almost insolubility in a single solvent (either ethanol or water). Transparent films were prepared with acidified solutions and possessed excellent mechanical properties with a tensile strength up to 40MPa and Young’s modulus of...

Fundamental pyrolysis thermal and kinetics properties for live vegetation that are essential to CFD modeling of pyrolysis and flammability were obtained from a series of small-scale tests for live and dead vegetation. The complexity of live leaf composition was recently documented allowing analysis of 12 crude compounds. Model simplification required a practical grouping into contents of (0) moisture, (1) lipids, (2) digestives (glucose, fructose, and protein), (3) hemicellulose (xylan and pectin), (4) glucan (cellulose and starch), (5) phenolic (lignin and tannins), and (6) inert (silicate...

A wealth of forensic wood identifcation technologies has been developed or improved in recent years, with many attempts to compare results between technologies. The utility of such comparisons is greatly reduced when the species tested with each technology are diferent and when performance metrics are not calculated or presented in the same way. Here, a species-level XyloTron computer vision model is presented along with a side-by-side comparison for species- and genus-level identifcation of the 10 species of Meliaceae studied by Deklerck et al. using mass spectrometry. The species-level...

Quantifying the cell wall polymers in wood and plants has been a tremendous challenge because no single method can achieve absolute quantification of any cell wall polymer. Two-dimensional NMR spectroscopic techniques have advanced this area with the introduction of wood dissolution and cryogenically cooled probes, allowing for semi-quantification. However, a more robust technique had to be developed to allow for a more absolute quantification of cell wall polymers. This study explored a multifaceted approach to accurately quantify lignin methoxyls using gas chromatography and mass...

Extrusion-based processes are one of the most widely used continuous polymer processing techniques because of their commercial availability, versatility, and cost-effective scal-ability. For these reasons, conventional single-screw extrusion was investigated and used for continuously processing mechanically fibrillated cellulose nanofibrils (CNFs) into wet sheets. A high shear mixing procedure was used to process highly loaded CNF pastes with up to ∼25 wt % solids, composed of ∼91 wt % CNF and ≤∼9 wt % of a processing aid like carboxymethyl cellulose (CMC), xanthan gum (XG), or anionic...