Wood and Fiber Science

Curve comparison in wood science: An introductory guide to common cases

Silvana Calvano — 2026-11-08

Empirical curves are essential for describing and analyzing phenomena in wood science. Although the theoretical framework is well established, the complexity of handling curves can hinder their proper application, which is likely to be more common in practice than generally assumed. This article aims to support the effective use and comparison of curves in wood science, and it is mainly intended as an accessible guide for approaching curve comparison, from the basic concepts of dependent and independent variables to the most complex of curve fitting and linearization. After a brief introduction and framework, this study addresses various key concepts, including types of curves, independent and dependent variables, linearization, and number of specimens required. These aspects are discussed through a methodological framework that can be useful in common situations. A section on avoiding common pitfalls is included as well. Proper confidence in handling curves is important not only to avoid errors, but also to enable their effective use, which can result in a more accurate description and a deeper understanding of phenomena.

Assessment of polycyclic aromatic hydrocarbons (PAHs) migration from creosote-treated Douglas-fir and southern pine posts over a 38-month period

Kaelin Quigley — 2026-11-08

Creosote is a widely used industrial wood preservative largely used for infrastructure-related applications such as utility poles, railway ties, and marine pilings. Polycyclic aromatic hydrocarbons (PAHs) are the predominant component, and some PAHs in creosote have been identified by the Environmental Protection Agency (EPA) as priority pollutants. While research on PAHs found in aquatic environments is widespread, studies on terrestrial PAH migration from creosote-treated wood commodities are less common. This study sought to quantify the extent (quantity, distance, and depth in soil column) of PAH migration from creosote-treated wood in ground contact by measuring the concentration of 16 EPA-regulated PAHs in soil around creosote-treated Douglas-fir and southern pine posts over a 38-month period. The concentrations of PAHs were highly variable from chemical to chemical and timepoint to timepoint, but a few trends were discernible. Where differences were apparent between the two wood species, soils around southern pine posts tended to have higher PAH concentration than soils around Douglas-fir posts, likely due to the differences in chemical retention in the outer 25 mm of the wood, at 143 kg/m³ and 52 kg/m³, respectively. Lighter PAHs, particularly naphthalene and acenaphthene, were often found in controls. This indicates that some of the lighter PAHs likely originated from a combination of environmental inputs such as wildfire smoke and vehicle emissions in addition to creosote. Distance from the post surface also played a role in determining PAH concentration for several PAHs. Several higher molecular weight PAHs (fluoranthene, pyrene, benz [a] anthracene, chrysene, benzo [a] pyrene and others) were more frequently identified in samples taken 15 cm from the post than in samples taken 30 cm from the posts in the later sampling times. This field study is ongoing and will continue to examine PAH migration from creosote-treated commodities.

Structural and chemical characterization of Douglas-fir and red alder biochar

Samuel Olajide — 2026-11-08

Biochar properties are often interpreted primarily as a function of pyrolysis temperature, but feedstock compositional differences can also influence the structural evolution of woody biochar. This study provides a complementary characterization of biochar produced from Douglas-fir (Pseudotsuga menziesii) softwood and red alder (Alnus rubra) hardwood forest residues under comparable pyrolysis conditions. Douglas-fir biochar was produced at 350°C, 500°C, and 700°C, while red alder biochar was produced at 500°C, using fast pyrolysis in a custom-built fluidized bed reactor. The biochar was characterized using proximate and elemental analysis, CO₂ BET surface area, pH, Raman spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Within the Douglas-fir series, increasing pyrolysis temperature decreased biochar yield, volatile matter, and oxygenated functional groups, while increasing gas yield, fixed carbon, alkalinity, surface area, and thermal stability. Under identical pyrolysis conditions at 500°C, red alder biochar retained greater C-H and O-H functionality and higher O/C and H/C ratios than Douglas-fir biochar. These differences were consistent with feedstock compositional differences, particularly the higher hemicellulose content and syringyl-guaiacyl lignin composition of red alder, which may favor retention of hydrogenated and oxygenated structures. In contrast, the higher guaiacyl lignin content of Douglas-fir may have contributed to greater carbon condensation, deoxygenation, and aromatization. Raman analysis showed increasing Iᴅ/Iɢ ratio with pyrolysis temperature, indicating changes in carbon structure during thermal reorganization. Feedstock differences were evaluated at 500°C, while temperature effects were assessed only for Douglas-fir. The results from this study link feedstock composition with differences in functional-group retention, carbon condensation, and thermal stability.

An investigation of the impact response of European ash and sycamore maple

Mojtaba Hassan Vand — 2026-11-08

European ash (Fraxinus excelsior L.) and sycamore maple (Acer pseudoplatanus L.) have long historical applications in structural components requiring high impact resistance, yet a detailed characterization of their full-field dynamic strain behavior remains limited. This study investigates the impact bending responses of both species using three-point drop-weight impact tests integrated with high-speed recording (10,000 frames per second) and the digital image correlation (DIC) method. The distinct and interactive effects of moisture content (MC) and growth-ring orientation (GO) were evaluated across key mechanical metrics: maximum deflection of the beam up to crack initiation, maximum normal strain, maximum reaction force (F_max), total absorbed energy, and impact bending strength (IBS). The IBS of ash and maple were 6.3 and 4.5 J/cm², respectively, while their maximum deflection was 8.5 and 8.6 mm, respectively. Two-way ANOVA revealed highly species-specific sensitivities to environmental and structural factors. For European ash, unlike F_max, other results such as maximum deflection, maximum strain, total absorbed energy, and IBS were not significantly altered by MC or GO. Conversely, sycamore maple exhibited highly isotropic behavior regarding GO, but it showed to be dependent on the MC. MC significantly enhanced the maximum deflection and maximum normal strain of maple, while triggering a severe 64% reduction in F_max. The force-time charts of the tests showed a distinct structural transition from a rigid, brittle fracture mode at low moisture levels to a highly dampening, ductile deformation mode once exceeding the fiber saturation point (FSP). These findings highlight the strong effect of species type on the impact mechanics, providing a robust experimental dataset essential for developing and validating analytical and finite element models.

Defining perpendicular to grain compression stress: A comparison of methods and recommendations for ASTM D143

Zoe Sperduto — 2026-11-08

The reliable characterization of structural properties is essential for safe and efficient structural design. This paper focuses on the behavior of lumber under compression load perpendicular to the grain. Emphasis is made on defining a standardized method for determining yield stress for tests performed in accordance with ASTM D143, primarily motivated by the need for well-defined material properties for finite element constitutive models. This research compared the existing standard test methods published by the European Committee for Standardization (CEN), International Standards Organization (ISO), and ASTM International by analyzing a series of tests performed in accordance with ASTM D143. A literature review showed that there is no dominant method for calculating strength of wood in compression perpendicular to the grain and that analysis methods are not always clearly described or aligned with the standard used for testing. Experimental results indicated that the various calculation methodologies produce significantly different strength properties; as such, a standardized calculation methodology should be implemented for use with ASTM D143 testing procedures. It is recommended that the methods for determining yield stress specified in EN 12512 should be applied to experimental data resulting from specimens tested in accordance with ASTM D143.