Discriminant Analysis of Geographical Origin of Cork Planks and Stoppers by Near Infrared Spectroscopy

The objective of this study was to assess the potential of visible and near infrared spectroscopy (VIS+NIRS) combined with multivariate analysis for identifying the geographical origin of cork. The study was carried out on cork planks and natural cork stoppers from the most representative cork-producing areas in the world. Two training sets of international and national cork planks were studied. The first set comprised a total of 479 samples from Morocco, Portugal, and Spain, while the second set comprised a total of 179 samples from the Spanish regions of Andalusia, Catalonia, and Extremadura. A training set of 90 cork stoppers from Andalusia and Catalonia was also studied. Original spectroscopic data were obtained for the transverse sections of the cork planks and for the body and top of the cork stoppers by means of a 6500 Foss-NIRSystems SY II spectrophotometer using a fiber optic probe. Remote reflectance was employed in the wavelength range of 400 to 2500 nm. After analyzing the spectroscopic data, discriminant models were obtained by means of partial least square (PLS) with 70% of the samples. The best models were then validated using 30% of the remaining samples. At least 98% of the international cork plank samples and 95% of the national samples were correctly classified in the calibration and validation stage. The best model for the cork stoppers was obtained for the top of the stoppers, with at least 90% of the samples being correctly classified. The results demonstrate the potential of VIS + NIRS technology as a rapid and accurate method for predicting the geographical origin of cork plank and stopper

Comparison of Methods for Estimating Mechanical Properties of Wood by NIR Spectroscopy

Near-infrared (NIR) spectroscopy provides a rapid alternative to traditional methods of wood property assessment. For organizations who assess wood properties on a large scale, multisite, multispecies calibrations are of practical interest. We examined NIR spectroscopy for the estimation of density (at 12% moisture content), modulus of elasticity (MOE), and modulus of rupture (MOR) using clear wood samples obtained from several pine species (Pinus caribaea var. bahamensis, var. hondurensis, and var. caribaea, P. chiapensis, P. maximinoi, P. oocarpa, P. taeda, and P. tecunumanii). We compared different methodologies for collecting spectra, that is, benchtop instrument versus benchtop fiber-optic probe and field portable fiber-optic probe, and different wood surfaces (radial and transverse). Calibrations based on the benchtop instrument were superior to those obtained using the fiber-optic probe systems. Difficulty with adequately representing the sample when collecting spectra using a fiber-optic probe and lower quality spectra explain the differences among the data sets. Spectra collected from radial and transverse surfaces provided similar calibration statistics. The calibrations obtained for density (R2 = 0.81, SECV = 38.5 kg/m3) and MOE (R2 = 0.81, SECV = 1124 GPa) using benchtop instrument spectra demonstrate that it is possible to obtain general calibrations for estimating the wood properties of a number of tropical, subtropical, and temperate pine species

Non-destructive evaluation techniques and what they tell us about wood property variation

To maximize utilization of our forest resources, detailed knowledge of wood property variation and the impacts this has on end-product performance is required at multiple scales (within and among trees, regionally). As many wood properties are difficult and time-consuming to measure our knowledge regarding their variation is often inadequate as is our understanding of their responses to genetic and silvicultural manipulation. The emergence of many non-destructive evaluation (NDE) methodologies offers the potential to greatly enhance our understanding of the forest resource; however, it is critical to recognize that any technique has its limitations and it is important to select the appropriate technique for a given application. In this review, we will discuss the following technologies for assessing wood properties both in the field: acoustics, Pilodyn, Resistograph and Rigidimeter and the lab: computer tomography (CT) scanning, DiscBot, near infrared (NIR) spectroscopy, radial sample acoustics and SilviScan. We will discuss these techniques, explore their utilization, and list applications that best suit each methodology. As an end goal, NDE technologies will help researchers worldwide characterize wood properties, develop accurate models for prediction, and utilize field equipment that can validate the predictions. The continued advancement of NDE technologies will also allow researchers to better understand the impact on wood properties on product performance

Salvaged lumber for Structural Mass Timber Panels: Manufacturing and Testing

Portland, OR, was the first US city to implement a deconstruction ordinance in 2016. Although salvaged lumber can have a high demand, the market for small-sized lumber from deconstructed dwellings is near saturation. New applications for this material are required for market development, industry diversification, and increasing deconstruction practices. Mass timber products such as cross-laminated timber (CLT) could be a new market for this material, but presently there is minimal information qualifying the performance of mass timber panels made with salvaged lumber. Three, full-sized 3-ply experimental layups, with varying amounts of salvaged/recycled wood content, were manufactured and tested to characterize panel properties. Manufacturing processes and testing methods followed ANSI/APA PRG 320-2018; Standard for Performance Rated Cross-Laminated Timber. Each panel layup had three replicates for nine panels in total. Panels measured 1.1 m by 2.3 m by 3 plys, and test results were used to calculate the effective flatwise bending moment resistance ((FbS)eff), effective flatwise bending stiffness ((EI)eff) effective shear stiffness in flatwise bending ((GA)eff), flatwise shear resistance (Vs), percent wood failure (WF%), and percent delamination (Delamination %). Results were compared with E3 grade 3-ply CLT panels made in the United States and indicated that salvaged lumber could be used as feedstock for mass timber panels in core layers or all layers. All panel layups passed benchmarks for (FbS)eff and (EI)eff  benchmarks with values greater than PRG320. Panels having salvaged lumber in core layer also met Vs benchmarks. Furthermore, all panels passed examination for WF% but struggled to meet delamination requirements. Possibilities exist for better performance if panels were made in a commercial setting. This research shows salvaged lumber has promise for manufacturing structural CLT, but more research and a larger samples size is needed to verify findings

EVALUATION OF LUMBER FROM DECONSTRUCTED PORTLAND RESIDENTIAL BUILDINGS

Portland, Oregon was the first U.S. city to implement a deconstruction ordinance in 2016. Although salvaged lumber from deconstructed dwellings can have high demand, the market for small-sized lumber is near saturation. New applications for this material are required for market development, industry diversification and the possible expansion of the deconstruction ordinance. Its use in mass timber is an option, but presently no wood property information exists for lumber from deconstructed dwellings inhibiting its use for structural purposes. Density and dynamic MOE (E) of 265, 38 mm x 89 mm (2 x 4) pieces of salvaged Douglas fir (Pseudotsuga menziesii) lumber were determined using a Metriguard Model 340 E-Computer. Additional data collected included sample dimensions, weight, and visual appearance. Over 50% of samples had a calculated stiffness comparable to the highest structural design grade for Coastal Douglas fir lumber. The presence of knots and damage, present in 66% and 59% of boards respectively, would likely downgrade boards, despite acceptable stiffness. Results show that 96% of samples were sufficiently stiff to meet minimum requirements for the manufacture of E3 grade cross laminated timber (CLT) panels and considering defects, this material is suitable for manufacturing CLT. Provision of wood property information for salvaged lumber is critical for market expansion and this work represents the first characterization of lumber from deconstructed Portland, OR dwellings