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Wang B.J.,FPInnovations Wood Products | Dai C.,FPInnovations Wood Products
Wood and Fiber Science | Year: 2013

In this study, a systematic approach was established for resource characterization via veneering and nondestructive testing. A recent study with short-rotation western hemlock (Tsuga heterophylla [Raf.] Sarg) and amabilis fir (Abies amabilis [Dougl.] Forbes) in British Columbia, Canada, was showcased to demonstrate the effectiveness of this approach. By proper tree sampling, veneer processing, and nondestructive testing on a sheet basis, the proposed approach helps rapidly address several critical issues on resource characterization and utilization, such as 1) the impact of stand characteristics on wood properties including density and modulus of elasticity (MOE) or attributes such as wood moisture content and color; 2) the within-tree and between-tree variations of these wood properties or attributes; 3) the spatial distribution of log defects, such as knots and decay; 4) the effect of tree growth rate, stem position, juvenile and mature wood, sapwood, and heartwood on key veneer properties such as thickness, surface roughness, density and MOE; and 5) veneer yield, visual grade, stress grade, and high-value product potentials. To maximize the value return from the available resource, this approach involves an assessment for product options with predicted grade outturns. © 2013 by the Society of Wood Science and Technology.

Hans G.,University of New Brunswick | Leblon B.,University of New Brunswick | Stirling R.,FPInnovations Wood Products | Nader J.,FPInnovations Forest Operations | And 2 more authors.
Forestry Chronicle | Year: 2013

Our study presents results of a test of a hand-held micro-electro- mechanical system (MEMS)-based near-infrared (NIR) spectrometer to estimate moisture content and basic specific gravity of black spruce frozen and unfrozen logs. The spectra were acquired on sapwood and heartwood as well as on tangential and transversal log sections. Partial least square regression was used to develop and validate the models that relate NIR spectral data to the log properties. Models were developed for the frozen and unfrozen logs separately (temperature-specific models) and for both kinds of logs together (generalized model). Both model types gave similar prediction accuracy and there were no temperature condition effects on the PLS model, for both moisture content and basic specific gravity estimation. This implies that the NIR spectrometer can be used whatever the log temperature conditions, even under freezing conditions.

Wang B.J.,FPInnovations Wood Products | Dai C.,FPInnovations Wood Products
Construction and Building Materials | Year: 2013

The key objective of this work was to investigate the feasibility of using short-rotation western hemlock (Tsuga heterophylla (Raf.) Sarg) and amabilis fir (Abies amabilis (Dougl.) Forbes) from coastal Britich Columbia, Canada for manufacturing structural laminated veneer lumber (LVL). Fourteen hem-fir logs were sampled, bucked and conditioned. Hem-fir veneer was then peeled, clipped, dried and visually graded. Combined hem-fir veneer was further segregated into three E grades based on dynamic modulus of elasticity (MOE). LVL billets were manufactured from each E grade and from two grade mixes, and evaluated for flatwise and edgewise bending MOE and modulus of rupture (MOR), and longitudinal shear strength. The results demonstrated that hem-fir veneer visual grade yield was about 15% B with the remainder C. No correlation existed between hem-fir veneer visual grades and E grades. Hem-fir LVL made from high E1 grade, medium E2 grade and low E3 grade could meet 2.2E, 1.8E and 1.5E product market requirements, respectively. Higher E grade veneer yielded higher LVL bending MOE, but not necessarily higher LVL shear strength. A good correlation was found between the LVL bending MOE and veneer mean MOE, and between the LVL bending MOR and MOE. Thus, the bending performance of the hem-fir LVL can be predicted based on veneer E grade and product lay-up. Pressing time changed clearly with the LVL lay-up with higher E grade requiring longer pressing time. Pressing time of mixed grade LVL fell within the times required for the two single grade lay-ups. Mixed grade LVL had a greater enhancement in flatwise than in edgewise, and was therefore more suitable for fabricating flanges of I-joists. Using a grade mix in the product lay-up allows low E grade veneer to be fully utilized for increased value recovery. The results of this study implied that without species segregation, the combined short-rotation hem-fir veneer can be successfully stress graded to manufacture structural LVL for building applications. © 2013 Elsevier Ltd. All rights reserved.

Haddadi A.,University of New Brunswick | Leblon B.,University of New Brunswick | Burger J.,BurgerMetrics | Pirouz Z.,FPInnovations Wood Products | And 2 more authors.
Wood Material Science and Engineering | Year: 2015

Abstract: Wood density (ρMC) and basic specific gravity (BSG) are important properties in several forest products manufacturing processes. In this study, near-infrared hyperspectral images were tested to produce two-dimensional (2D) ρMC and BSG images of subalpine fir (Abies lasiocarpa Hook) board. A total of 107 cubic samples with the size of 4 cm were prepared from 14 boards. All samples were dried to various moisture contents (MCs) during several steps until being completely dried. The resulting MCs ranged from 1% to 137% (dry basis). After the last drying step, the samples were soaked in water to determine BSG. Hyperspectral images and weight measurements were acquired over each sample at each drying step. ρMC was also estimated at each MC level. Partial least squares (PLS) models were developed for estimating both ρMC and BSG from the near-infrared hyperspectral imaging (NIR-HSI) system absorbance spectra acquired over all the samples during each drying step. The ρMC model provides a reasonable accuracy with the validation data-set (R2 = 0.81, RMSE = 39 kg/m3, and RPD = 2.3). For BSG, only models built with samples having MC of less than 12% are significant. The calibration data-set provides similar accuracy as the ρMC model (RMSE = 0.004, R2 = 0.82, and RPD = 2.28), but the accuracy is lower with the validation data-set (RMSE = 0.007, R2 = 0.53, and RPD = 1.39). Our data-set has BSG values varying only from 0.326 to 0.374, and further work is needed to apply these methods to a data-set that includes a more extended range of BSG variations for improving estimation accuracy. © 2015, Taylor & Francis.

Elustondo D.,FPInnovations Wood Products | Oliveira L.,FPInnovations Wood Products
Wood Material Science and Engineering | Year: 2011

A Lumber Quality Model developed to predict lumber grade after drying was applied and validated in industry. The model was calibrated with a 198-piece lumber package that was dried at a local sawmill in British Columbia, Canada, and 30 sawmill grade reports were recorded from 2008 to 2010. The calibrated model was then used to predict the target moisture content that would result in the maximum lumber value. It was predicted that lumber value should increase by approximately 17 CAD (Canadian dollars) m -3 if the target moisture content were reduced from the historic 17% to an optimum of approximate 13%. The sawmill implemented the recommendations and the predictions were validated with another seven industrial drying runs. © 2011 Copyright Taylor and Francis Group, LLC.

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