Treesearch

Early illustrations of juvenile wood in hard pines have depicted a central core of wood, varying little by diameter or cambial age, to be nested within mature wood tapering to the upper portion of the stem; other depictions show greater complexity in attributing the variability of this central core of wood with its proximity to the crown and/or actual maturity of the tree when the wood was formed. The present discussion addresses the degree to which different representations of juvenile wood (corewood) are applicable to mature longleaf pine (Pinus palustris Mill.) trees. Wood property maps...

Cross Laminated Timber (CLT) is part of a new generation of engineered wood products that are now widespread across Europe, Australia, and Canada. As this trend is now growing in the United States, manufacturers are looking to expand the use of CLT into the North American market, which includes states located in the southeastern U.S. As this region is known to have an increased risk of termite attack, standards should be developed to evaluate termite damage on CLT products prior to extensive use of the product in this region. However, existing standard test methods cannot be applied...

In this report, wooden members of sizes typically used in bridge construction are examined using x-ray computerized tomography (CT) to determine the presence of internal decay. This report is part of an overall study in which Douglas-fir (Pseudotsuga menziesii) glue-laminated (glulam) beams and solid sawn timbers were inoculated with brown rot fungus, Fomitopsis pinicola, and exposed to aboveground conditions approximately 25 miles (40 km) north of Gulfport, Mississippi, USA. The goal of the overall study is to develop interior decay within the test specimens and then identify and character...

The study summarized in this report was conducted to examine the relationships between nondestructive evaluation parameters and the modulus of elasticity (MOE) of spruce–pine–fir structural lumber. A random sample of lumber was obtained from a local lumber yard and conditioned to approximately 10% equilibrium moisture content in the laboratory. Static bending and vibration (transverse and longitudinal) nondestructive tests were conducted on each specimen, and MOE was calculated. The relationship between static and dynamic modulus values was examined, and empirical models were developed...

The fammability of synthetic thermoplastic polymers has been recognized as an increasingly important safety problem. The goal of this study was to evaluate a green and safe fre-retardant system comprising of cellulose nanocrystals (CNC) and zinc oxide nanoparticles (ZnO). CNCs coated with nano ZnO were incorporated in the high-density polyethylene polymer (HDPE) matrix at different concentrations. Fire testing results of different formulations of HDPE containing 0.4 to 1.0% zinc oxide coated CNC exhibited a substantial decrease in the average mass loss, peak heat release rate and total...

The literature related to the phenomenon of pseudo-truncation has emphasized that the mechanical property distributions of graded lumber subpopulations are determined by the mechanical property distributions of the mill-run (or full) lumber populations from which the subpopulations are formed. Whereas previous studies have shown that the means and variances of mechanical properties in the same visual grade of lumber can vary from mill to mill, there have been no studies on the stability of the means and variances of modulus of elasticity (MOE) and modulus of rupture (MOR)in mill-run lumber...

Timber genus identification based on the anatomical features of wood is well established in botany. However, species-level wood identification is not always possible based on traditional wood morphology techniques alone. To compensate for the deficiencies of traditional methods, direct analysis in real time coupled to Fourier transform ion cyclotron resonance mass spectrometry (DART-FTICR-MS) was used to obtain the mass spectral fingerprints of different timber species. Using heartwood samples of two morphologically similar species, Pterocarpus santalinus and Pterocarpus tinctorius,...

Roundwood is increasingly sourced from highly productive plantations that yield excellent growth. Information is needed on the wood properties from plantations because these trees will contain a higher proportion of low stiffness corewood compared to naturally regenerated trees of the same size. The objective of this study was to examine the within-tree variation in stiffness for Douglas-fir and loblolly pine grown in the United States through assessment of specific gravity (SG) and ultrasonic velocity (USV). Approximately 500 pith-to-bark radial strips collected from multiple height...

Fused borate rods were installed at equal distances along the length of unseasoned red or white oak bridge timbers. Moisture content and boron levels were examined at 15 and 30 weeks after rod installation at various points along the bridge timbers. Moisture contents for both red and white oak were greater than 60% at all time checks. Boron levels were highest near the point of borate rod placement, but high levels were also recorded 4 and 6 inches from the rod installation point. Boron levels transverse to the boron rod installation point were lower than in the longitudinal direction....

The objective of this study was to determine the feasibility of using a transverse free vibration testing method to nondestructively evaluate the bending stiffness and strength of full-size (1220 x 2440 mm) wood composite panels (WCPs). Based on the principle of transverse free vibration of a thin plate, the dynamic modulus of elasticity (MOE) of a full-size WCP supported on two nodal-lines was derived using the Rayleigh method. Transverse free vibration test was conducted on 54 full-size medium density fiberboard (MDF) panels and 36 full-size particleboard (PB) panels under a two-nodal-lin...