Wood and Fiber Science

A multiplex qPCR assay for the identification of Pinus palustris and Pinus elliottii

2026-02-13T16:27:08+00:00

Differentiating the wood of high-strength southern yellow pines (Pinus palustris and P. elliottii) from their lower-strength congeners (P. taeda and P. echinata) presents a substantial challenge once diagnostic external features, such as needles, cones, and bark are absent. This difficulty arises from their wood anatomical indistinguishability and low genetic resolution driven by highly conserved genome organization and extensive allele sharing. To address this, we developed and validated a multiplex qPCR assay utilizing SYBR Green chemistry and asymmetric primer concentrations, working with leaf and seed DNA. The assay targets short amplicons (<100 bp) to maximize the likelihood of amplification of the fragmented DNA typical of solid wood. The method achieved high linearity (R² > 0.99) and efficiency, successfully co-amplifying targets while maintaining clear discrimination through distinct mean melting temperatures (77.98°C [SD 0.11] and 69.25°C [SD 0.26], respectively). Sensitivity testing established limits of detection at 1 pg for Pinus palustris and 10 pg for Pinus elliottii. Validation across a panel of 84 individuals representing all four species yielded 100% accuracy, precision, and recall. This study establishes a rapid, gel-free molecular diagnostic tool that overcomes the limitations of wood anatomical identification. By validating a short-amplicon design on leaf and seed tissues, it provides a proof-of-concept for future applications on solid wood and offers a reproducible methodological framework for species verification.

Performance of light-frame shear wall framed with Japanese lumber

2026-01-27T18:21:05+00:00

Recently, Hinoki and Sugi, two predominant wood species in Japan, had approval for their design values to be listed in the National Design Specification for wood-frame construction in the United States. However, their ability to meet the demands of a light-framed shear wall has not been studied. The objective of this study was to characterize the behavior of Hinoki and Sugi framed shear walls with conventional sheathing material, and compare the performance to Douglas-fir framed shear walls. Twelve light-frame shear walls were constructed, and one monotonic and three cyclic tests were performed per wall type consisting of Douglas-fir, Hinoki, and Sugi. Hinoki showed similar properties to that of Douglas-fir, while Sugi observed a lower lateral resistance and stiffness compared to the Douglas-fir. All walls in this study met seismic equivalent parameters, which allow the wall configurations used in this study to be compared to other wood-frame sheathed wall types.

Biological durability of preservative treated cross-laminated timber (CLT) made with southern pine lumber

2026-02-16T14:54:19+00:00

Cross-laminated timber (CLT) is an engineered wood product that is being increasingly utilized in structural applications. However, its susceptibility to fungal decay and termite attack raises concerns about long-term durability, particularly in high-moisture and insect-prone environments. This study evaluates the biological durability of CLT fabricated with southern pine and treated post-layup with two copper-based preservatives: copper azole (CA-C) and micronized copper azole (MCA) under laboratory conditions. Fungal decay resistance was assessed using brown-rot (Serpula lacrymans) and white-rot (Irpex lacteus) fungi, while termite resistance was evaluated through exposure to Reticulitermes spp. Results showed that preservative treatments significantly reduced fungal decay and termite damage compared to untreated controls, although treatment effectiveness varied with CLT configuration (3-ply or 5-ply). While both preservatives effectively mitigated decay in 3-ply panels, treated 5-ply panels exhibited comparable mass loss to untreated counterparts. Termite resistance tests demonstrated that MCA and CA-C treated CLT samples exhibited significantly lower mass loss and higher termite mortality compared to the untreated controls, with both preservatives providing comparable protection.

Interface shear capacity of veneer-based cross-laminated timber glued-in rod splice connections

2026-03-17T11:42:23+00:00

North America’s engineered mass timber sector has expanded rapidly in the past decade, with growing adoption of mass timber products as structural components in tall buildings. Among these, mass timber panels have emerged as viable shear wall elements for lateral force-resisting systems. In taller balloon-type or self-centering rocking wall constructions, panels are stacked vertically, necessitating reliable splice connections between adjacent panels. This paper introduces a novel glued-in rod (GiR) splice connection for vertical joints between stacked panels, featuring a two-stage adhesive installation process and a filler/weep hole system designed to promote full adhesive penetration and accommodate construction tolerances. An experimental program was conducted to evaluate the interface shear strength of GiRs embedded in veneer-based cross-laminated timber under both monotonic and reversed-cyclic loading. Unlike previous studies that focused on tensile strength or monotonic loading only, this work investigates shear behavior relevant to seismic and wind demands. Experimental results are compared against conservative yield strength predictions from the U.S. National Design Specification for Wood Construction (NDS) dowel-type equations. Findings offer new insights into the shear performance of GiR splices in veneer-based cross-laminated timber, informing design assumptions for vertical panel joints in balloon-type mass timber wall systems and providing experimentally validated allowable loads for seismic design.

Mass timber seismic lateral force resisting systems: Testing of a full-scale three-story structure

2026-05-31T05:55:33+00:00

Over the last decade, the North American market for mass timber (MT) has diversified with the development of several engineered wood panelized products. Among these, a recent veneer-based product known as mass ply panel (MPP) has been introduced and certified per ANSI-PRG 320. To further demonstrate the potential of such engineered wood panelized products, a study was conducted to develop innovative solutions for enhanced design to low-damage seismic lateral force-resisting systems (LFRS). This paper presents an overview of the study, in which a three-story MT building was designed following performance-based design methods and constructed at Oregon State University (OSU). The gravity system includes laminated veneer lumber beams and columns and MPP floors. Two different LFRS for balloon-type MPP shear walls were studied. The first LFRS consisted of a pivoting MPP panel with steel buckling-restrained boundary elements (BRB) as energy dissipators. The second system utilized a rocking MPP panel with post-tensioned steel rods to provide self-centering capacity and U-shaped flexural plates (UFP) to dissipate energy. There were four testing phases, including two phases (Phases 0.1 and 0.2) that applied lateral loads to the gravity system only, before and after testing of LFRS; Phase 1, which included lateral testing of the building structure with an BRB-MPP shear wall; and Phase 2, which included lateral testing of the building structure with an UFP-MPP shear wall. In all four phases, the building was subjected to quasi-static cyclic tests following a CUREE protocol up to maximum 4% roof lateral drift. A summary of building details, experimental setup and key results is presented in this paper.