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An extensive summary of publications reporting radial specific gravity (SG) variation for North American conifers is presented. SG varies from pith to bark in three distinct patterns before reaching asymptomatic values: Type 1 (SG increases with cambial age), Type 2 (SG is initially high at the pith, then decreases with cambial age, before increasing), and Type 3 (SG decreases with cambial age). Pinaceae have either a Type 1 or 2 pattern (majority are Type 2). Cupressaceae have a Type 3 pattern, but radial SG data do not exist for some species. We reviewed publications in table 7-1 of Panshin and de Zeeuw (the 1970 edition) which reports SG variation by species and Type (the 1980 edition has an equivalent table but does not reference publications), examining sampling strategies and radial patterns. For a small number of species, Type was either incorrectly interpreted or sampling made a conclusion regarding pattern of radial variation impossible. Specific examples of mislabeled Types reported by Panshin and de Zeeuw for Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), red pine (Pinus resinosa) and shortleaf pine (Pinus echinata), and western redcedar (Thuja plicata) are described. We conclude for nearly all species the pattern of radial SG variation is consistent; however, different patterns have been reported for eastern white pine (Pinus strobus) and subspecies of Douglas-fir and ponderosa pine (Pinus ponderosa). Key words: North American conifers, specific gravity, radial variation, Type 1, 2, or 3 L'etude presente un resume complet des publications rapportant la variation de la gravite specifique radiale (GS) pour les coniferes d'Amerique du Nord. La gravite specifique radiale varie de la moelle a l'ecorce selon trois schemas avant d'atteindre des valeurs asymptomatiques : Type 1 (la GS augmente avec l'age cambial), Type 2 (la GS est initialement elevee a la moelle, puis diminue avec l'age avant d'augmenter) et Type 3 (la GS diminue avec l'age cambial). Les Pinaceae d'Amerique du Nord ont un schema de Type 1 ou 2 (la majorite des arbres sont de Type 2). Les Cupressaceae presentent un schema de Type 3, mais il n'existe pas de donnees sur la GS radiale pour certaines especes. Nous avons passe en revue les publications du tableau 7-1 de Panshin et de Zeeuw (l'edition de 1970) qui rapporte la variation de la GS par espece et par type (l'edition de 1980 possede un tableau equivalent, mais ne fait pas reference aux publications), en examinant les strategies d'echantillonnage et les modeles radiaux. Pour un petit nombre de ces especes, le type etait soit mal interprete, ou encore l'echantillonnage rendait impossible toute conclusion concernant le schema de variation radiale. Nous decrivons des exemples specifiques de types mal etiquetes rapportes par Panshin et de Zeeuw pour le Douglas (Pseudotsuga menziesii), le pin tordu (Pinus contorta), le pin rouge (Pinus resinosa), le pin a feuilles courtes (Pinus echinata) et le thuya occidental (Thujaplicata). Nous concluons qu'a l'interieur d'une espece individuelle, le modele de variation radiale de la GS est coherent, mais que des modeles differents ont ete signales pour le pin blanc de l'Est (Pinus strobus) et pour les sous-especes de sapin de Douglas et de pin ponderosa (Pinus ponderosa). [Traduit par la Redaction] Mots-cles : coniferes d'Amerique du Nord, gravite specifique, variation radiale, type 1, 2 ou 3, Introduction Wood density or specific gravity (SG), defined as wood density divided by the density of water, is considered by many to be the most important wood property as it [...]

North American conifers exhibit three radial specific gravity (SG) patterns (Type 1, 2, and 3), which balance hydraulic and mechanical requirements. Type 1 and 2 patterns (Pinaceae) have low SG and high microfibril angle (MFA) corewood ensuring compliance, whereas in outerwood high SG/low MFA provide stiffness and strength resisting bending. Hydraulically, corewood, especially in Type 2 species, is resistant to embolism, whereas outerwood has higher specific conductivity. Cupressaceae (Type 3) have hydraulically very efficient, low SG outerwood, facilitating rapid growth. Corewood is flexible, whereas outerwood is mechanically weak and compensated for by more conical stems and durable heartwood (which prevents Brazier buckling). Radially earlywood (EW) decreases, and latewood (LW) increases for all types, whereas %latewood (%LW) increases (Type 1), decreases, then increases (Type 2) and decreases (Type 3). Ring SG increases when increasing LW SG and %LW are sufficient to counteract decreasing EW SG. Shade tolerance, crown recession, hormone gradients, and environmental variation affect patterns. Auxin concentration decreases with increasing distance from juvenile foliage slowing cell division, concomitantly gibberellin concentration (lignification) and carbohydrates (cell wall thickening) increase, producing higher %LW. Across a species range regions receiving relatively high summer rainfall have trees with higher %LW (by ring). [ABSTRACT FROM AUTHOR]

A chemistry-based explainable machine learning (ML) approach was used to predict wood properties using near infrared (NIR) spectral data collected from rough and smooth surfaces, and to provide better understanding of the role of important NIR wavelengths (features) in the performance of ML models. NIR spectra collected from western hemlock (Tsuga heterophylla) and coastal Douglas-fir (Pseudotsuga menziesii) boards with rough and smooth surfaces were fed into random forest and TreeNet; a gradient boosting machine algorithm, for predicting wood density, modulus of elasticity (MOE) and modulus of rupture (MOR). The TreeNet model could predict the MOE, MOR, and density with R2 of 0.66, 0.64, and 0.64 using spectra collected from rough surface and R2 of 0.54, 0.46, and 0.46 using spectra collected from smooth surface. TreeNet outperformed the random forest, and for both ML algorithms higher R2 and lower error were obtained using NIR data collected from rough surfaces. This suggested that for Douglass fir and western hemlock, NIR spectra could be collected on a sawn surface prior to surface planing. However, it is difficult to generalize the impact of surface roughness on the performance of predictive model as different factors (e.g. what constitutes a smooth or rough surface, variability of data set in terms of wood properties) impact the success of predictive models. NIR features having the greatest influence on TreeNet models were examined and consistently had wood chemistry specific band assignments. The most important features occurred in the O-H first overtone, and C–H second overtone regions and a narrow zone (approximately 2400–2500 nm) of the C–H stretch C–C stretch combination region. Important features also differed by property and with surface roughness. Explaining ML model performance using the relative importance of the NIR features showed the importance of wood chemistry related information when developing models, however MOE and MOR TreeNet models based on smooth surface NIR spectra showed an increased importance of water related features. Overall, the chemistry-based explainable machine learning model approach allows for identification of important NIR features, and regions, and aids in understanding how they contribute to the performance of NIR-based wood property predictive models. [ABSTRACT FROM AUTHOR]

Hyperspectral imaging is a technique that combines spectroscopy and imaging. Originally utilized in the 1980's by the remote sensing community it is now utilized in a wide variety of applications. Spectral imaging was first used for the detection of compression wood in the late 1990's and since that time research focused on wood and wood products has steadily increased with a variety of applications reported. While there are several reviews of wood related research utilizing near infrared spectrometers a comprehensive summary of wood—hyperspectral imaging research is lacking. Near infrared hyperspectral imaging systems (NIR-HSI) typically have a wavelength range of 900–1700 nm, whereas short-wave infrared hyperspectral imaging (SWIR-HSI) systems range from 1000 to 2500 nm. We provide a detailed account of the various studies that have been published utilizing both camera types. [ABSTRACT FROM AUTHOR]

Wood stiffness (modulus of elasticity, MOE) is an important property for conifer wood, with the variability in MOE largely being a function of both the specific gravity (SG) (wood density) and the angle of the microfibrils within the S2 layer of longitudinal tracheids. Rapid analysis techniques can be used together to quantify MOE; while SG can be determined with relative ease, this is not the case for microfibril angle, requiring expensive X-ray diffraction equipment. An alternative to microfibril angle is to measure longitudinal acoustic velocity. The objective of this study was to measure and then model the within tree variation in dynamic MOE (MOEdyn) by developing the methodology to measure ultrasonic velocity (USV) in radial samples from pith to bark using ultrasonic frequencies (>20 kHz). A total of 419 pith-to-bark radial strips, collected from multiple height levels in 92 loblolly pine (Pinus taeda) trees, were processed to obtain matching SG (2mm longitudinal) and USV (8.2-mm longitudinal) samples. Ring-by-ring SG was measured using X-ray densitometry and time-of-flight USV was measured at a 10-mm radial resolution from pith to bark. A subset of samples was sent to SilviScan to determine microfibril angle using X-ray diffraction. The relationship between microfibril angle and USV was strong (R 2 = 0.91, RMSE = 2.6°). Nonlinear mixed-effects models were then developed to predict radial variation in SG, USV and MOEdyn. Fixed effects for the models, which included cambial age and height of disk within tree, had pseudo R 2 values of 0.67 for SG (RMSE = 0.051), 0.71 for USV (RMSE = 316 m/s) and 0.69 for MOEdyn (RMSE = 1.9 GPa). When combined with SG measurements from X-ray densitometry, USV measurements from pith to bark are a powerful tool for assessing variability in wood stiffness. [ABSTRACT FROM AUTHOR]

Composition of the southern pine forest is now predominated by two species, loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.), owing to fire suppression activities, natural regeneration on abandoned agricultural lands, and extensive planting. Comparison of the wood and bark physical properties of these pines is of interest in terms of the yields of usable biomass and, for the bark, its ecological functionality on a living tree. Trees from a species comparison study were used to generate wood and bark property data, on a whole-tree basis, and for stem disks collected at breast height. Models were constructed to explain the effect of relative height on wood and bark properties. When comparing the whole-tree data, slash pine wood (0.523 versus 0.498) and bark (0.368 versus 0.311) specific gravity values were higher, both offset by lower moisture contents; slash pine also produced a higher percentage of bark on a dry-mass basis (17% versus 12.5%). Unlike wood properties, bark properties showed significant between-species differences when determined at breast height alone, the exception being moisture content. In terms of yield, harvests of a green tonne of loblolly pine and slash pine would give approximately the same dry mass of wood, but slash pine provides more bark. Key words: bark thickness, moisture content, specific gravity, wood quality, yield. La composition de la foret de pins du sud est maintenant dominee par deux especes, le pin a encens (Pinus taeda L.) et le pin d'Elliott (Pinus elliottii Engelm.) a cause des activites de suppression des feux, de la regeneration naturelle sur les terres agricoles abandonnees et de la plantation intensive. La comparaison des proprietes physiques du bois et de l'ecorce de ces deux pins presente un interet en termes de rendement de la biomasse utile, et dans le cas de l'ecorce, sa fonction ecologique sur un arbre vivant. Les arbres faisant partie d'une etude comparative entre especes ont ete utilises pour generer des donnees sur les proprietes de l'ecorce et du bois sur une base d'arbre entier et pour des rondelles de tige prelevees a hauteur de poitrine. Des modeles ont ete construits pour expliquer l'effet de la hauteur relative sur les proprietes du bois et de l'ecorce. Lorsqu'on les compare sur une base d'arbre entier, les valeurs de densite du bois (0,523 versus 0,498) et de l'ecorce (0,368 versus 0,311) du pin d'Elliott sont plus elevees, compensees dans les deux cas par une teneur en humidite plus faible; le pin d'Elliott produit egalement une plus forte proportion d'ecorce (17% versus 12,5%) sur une base de masse anhydre. Contrairement aux proprietes du bois, les proprietes de l'ecorce des deux especes sont significativement differentes lorsqu'elles sont mesurees a hauteur de poitrine seulement, la teneur en humidite faisant exception. En termes de rendement, la recolte d'une tonne verte de pin a encens ou de pin d'Elliott donne approximativement la meme masse anhydre de bois mais le pin d'Elliott produit plus d'ecorce. [Traduit par la Redaction] Mots-cles: epaisseur de l'ecorce, teneur en humidite, densite qualite du bois, rendement., Introduction The species composition of the pine forest of the southeastern United States has changed over the years, from the vast occurrence of longleaf pine (Pinus palustris Mill.) before colonial [...]

Rubberwood (Hevea brasiliensis Muell. Arg) is underutilized in most developing countries but has potential to be a solution to the shortage of wood for pulp, paper and wood composite products at the end of its production cycle. Determining and understanding its fibre properties (fibre dimensions and morphology) is key in its utilization for pulp and paper as well as composites. This study assessed the effect of age on the fibre properties of rubberwood. Samples of wood at four ages (10, 15, 20 and 25 years) were obtained at both the axial (base and top of merchantable length) and radial direction (innerwood, middlewood and outerwood). Slivers were obtained from the samples and macerated to provide individual fibres for optical measurement. Fibre dimensions at the four ages were measured, and their morphology was determined. Fibre properties and morphology were significantly affected by age at p = 0.05. Average fibre length was 1.47 ± 0.12 mm, with non-constant variation observed across the different ages, and from pith to bark. Average lumen width was 16.87 µm, and fibre diameter ranged from 25.02 µm to 27.23 µm. The fibre properties of rubberwood potentially make it suitable for pulp and paper production as well as wood composite boards. [ABSTRACT FROM AUTHOR]

There is a growing interest in improving wood properties through the appropriate selection of seed provenances within species. In this study, wood density and mechanical properties were investigated for Acacia mangium trees from six different provenances, planted in Quang Tri, Vietnam. Radial and among provenance variation in stress wave velocity (SWV), wood density (WD), dynamic modulus of elasticity (MOEd), modulus of rupture (MOR), and modulus of elasticity (MOE) were determined on a total of 480 small clear specimens (20 × 20 × 300 mm) cut from 30 trees (five per provenance). SWV and selected wood properties near the pith were significantly lower than those near the bark. Differences in all selected mechanical properties among provenances were significant. The highest static properties (MOR and MOE) were found for the Long Thanh provenance indicating its potential suitability for breeding programs in Vietnam focused on improving A. mangium wood quality. A high positive correlation coefficient was found between MOEd and MOE (r = 0.93, P < 0.001) and our results indicate that the stiffness of A. mangium can be predicted using stress wave method provided the density of measured element is known. [ABSTRACT FROM AUTHOR]

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5 mm in diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core density, latewood and earlywood density, and latewood percent) were measured for each tree sampled in the study. Overall, growth properties were better for full-sib seedling than for clonal lines, whereas wood density was higher for clonal lines than full-sib and open-pollinated seedlings. However, there were clonal lines with better growth and higher wood density. Clonal repeatability of both growth and wood properties across sampled sites and genetic correlations between growth and wood traits were determined, with higher repeatability observed for wood traits compared with growth traits. Significant genetic correlations were observed for tree height and wood properties, whereas weak correlations were observed for diameter and wood properties. Resume: L'utilisation de varietes clonales en foresterie presente un fort potentiel pour ameliorer les traits de croissance (quantite) et de proprietes du bois (qualite) du pin a encens (Pinus taeda L.). Des pins a encens issus de l'embryogenese somatique (clones), de croisements de descendances biparentales et de descendances uniparentales allofecondees ont ete echantillonnes pour identifier la variation dans la croissance et les proprietes du bois dans et entre les lignees clonales et les temoins zygotiques. Des carottes de 5 mm de diametre ont ete prelevees a l'age de 4 ans sur un total de 2615 arbres. Les proprietes de la croissance (diametre a 1.4 m et la hauteur totale de l'arbre) ainsi que les proprietes du bois (densite globale de la carotte, densite du bois initial et du bois final et pourcentage de bois final) ont ete mesurees pour chacun des arbres echantillonnes dans l'etude. Dans l'ensemble, les proprietes de la croissance etaient meilleures chez les semis issus de descendances biparentales que chez lignees clonales alors que la densite du bois etaient plus elevee chez les varietes clonales que chez les semis issus de descendances biparentales ou uniparentales allofecondees. Cependant, certaines lignees clonales avaient une meilleure croissance et une plus grande densite du bois. La reproductibilite clonale des proprietes de la croissance et du bois parmi les stations ainsi que les correlations genetiques entre les traits de croissance et de proprietes du bois ont ete determinees; la reproductibilite des traits de proprietes du bois etait meilleure que celle des traits de croissance. Des correlations genetiques significatives ont ete observees entre la hauteur des arbres et les proprietes du bois alors que de faibles correlations ont ete observees entre le diametre et les proprietes du bois. [Traduit par la Redaction], Introduction Genetic improvement programs for loblolly pine (Pinus taeda L.) began in the 1950s in the United States (US) with the aim of producing abundant high-quality seedlings to support planting [...]

: Conventionally, increment cores collected at breast height (1.4 m) have been used to measure wood properties of standing loblolly pine (Pinus taeda L.) trees. This height has been used because of the ease of sampling and cost involved in extracting the cores. In this study, the efficacy of a breast-height core to represent whole-tree specific gravity (SG) and moisture content (MC) was examined. The sampling height that best represents whole-tree SG and MC was identified using the correlation between volume-weighted whole-tree SG and MC with SG and MC measurements collected at different heights within a tree. We found a high correlation between observed whole-disk SG and MC with volume-weighted whole-tree SG and MC at most sampling heights. The strength of the correlation followed a skewed parabolic curve form for both wood properties. The strongest correlations were observed between 4.6 and 6.1 m, with marginally lower correlations at the base of the tree, and the weakest correlations were observed towards the tip of the tree. In addition, it was found that the number of stands and trees that need to be sampled to achieve a certain accuracy in overall mean whole-tree SG and MC was greater if breast height was used as a sampling height compared with the most representative sampling heights identified (4.6 m for SG and 6.1 m for MC). Resume: Les carottes utilisees pour mesurer les proprietes du bois des tiges sur pied de pin a encens (Pinus taeda L.) ont communement ete prelevees a hauteur de poitrine (1,4 m). Cette hauteur a ete utilisee a cause de la facilite d'echantillonnage et du cout d'extraction des carottes. Dans cette etude, nous avons examine si une carotte prelevee a hauteur de poitrine representait efficacement la densite basale (DB) et la teneur en humidite (TH) de l'arbre tout entier. La hauteur d'echantillonnage qui represente le mieux la DB et la TH de l'arbre tout entier a ete identifiee en utilisant la correlation entre la DB et la TH de l'arbre tout entier ponderees par le volume et la DB et la TH mesurees a differentes hauteurs dans l'arbre. Nous avons trouve une correlation etroite entre la DB et la TH observees de rondelles entieres et la DB et la TH de l'arbre tout entier ponderees par le volume pour la plupart des hauteurs echantillonnees. Le degre de correlation suivait une courbe parabolique asymetrique pour les deux proprietes du bois. Les plus fortes correlations ont ete observees entre 4,6 et 6,1 m; les correlations etaient legerement plus faibles a la base de l'arbre et les plus faibles vers le sommet de l'arbre. De plus, le nombre de peuplements et d'arbres qui doivent etre echantillonnes pour obtenir une certaine precision de la moyenne globale de la DB et de la TH de l'arbre tout entier etait plus grand si l'echantillonnage etait fait a hauteur de poitrine comparativement aux hauteurs d'echantillonnage identifiees comme les plus representatives (4,6 m pour la DB et 6,1 m pour la TH). [Traduit par la Redaction], Introduction Loblolly pine (Pinus taeda L.) is the most important plantation species in the southern United States (US) and represents more than half of the standing pine volume in this [...]

Modulus of elasticity (MOE), modulus of rupture (MOR), and specific gravity (SG) are important properties for determining the end-use and value of a piece of lumber. This study addressed the variation in MOE, MOR, and SG with physiographic region, tree height, and wood type. Properties were measured from two static bending samples (dimensions 25.4 mm x 25.4 mm x 406.4 mm) representing each wood type (corewood and outerwood) at heights 2.4, 7.3, and 12.2 m from three trees sampled from 135 loblolly pine (Pinus taeda L.) stands distributed across the natural range of the species. An analysis of variance was conducted to detect the effect of physiographpic region, height, and wood type on each property. Significant regional variation was observed for MOE, MOR, and SG for both wood types with high values in the Gulf and South Atlantic Coastal Plains compared with other regions. A significant height-related trend in MOE, MOR, and SG within a tree was identified; MOE and MOR increased in corewood and decreased in outerwood with height. Maps showing regional variation in MOE and MOR at different heights by wood type were produced and showed significant variation for both properties. Resume: Le module d'elasticite (MOE), le module de rupture (MOR) et le poids specifique (PS) sont des proprietes importantes pour determiner l'usage final et la valeur d'une piece de bois. Cette etude a porte sur la variation de ces proprietes en fonction de la region physiographique, de la hauteur de l'arbre et du type de bois. Les proprietes ont ete mesurees en flexion statique sur deux eprouvettes (dimensions de 25,4 mm x 25,4 mm x 406,4 mm) representant chaque type de bois (bois juvenile et bois mature) a des hauteurs de 2,4, 7,3 et 12,2 m dans trois arbres preleves au sein de 135 peuplements de pin a encens (Pinus taeda L.) distribues dans l'ensemble de l'aire de repartition naturelle de l'espece. Une analyse de variance a ete realisee afin de detecter les effets de la region physiographique, de la hauteur et du type de bois sur chaque pro-priete. Une variation regionale significative du MOE, du MOR et du PS a ete observee dans les deux types de bois, avec des valeurs elevees dans le Golfe et dans les plaines cotieres de l'Atlantique Sud comparativement aux autres regions. A l'interieur de l'arbre, une tendance significative reliee a la hauteur a ete identifiee pour le MOE, le MOR et le PS; le MOE et le MOR augmentaient dans le bois juvenile et diminuaient dans le bois mature en fonction de la hauteur. La cartographie des variations regionales du MOE et du MOR a differentes hauteurs et par type de bois montrent que ces deux proprietes varient grandement. [Traduit par la Redaction], Introduction The southeastern United States is a critically important region of the world in terms of lumber manufacture, with production greater than any other single nation in the world. It [...]

Acoustic tools are increasingly used to estimate standing-tree (dynamic) stiffness; however, such techniques overestimate static stiffness, the standard measurement for determining modulus of elasticity (MOE) of wood. This study aimed to identify correction methods for standing-tree estimates making dynamic and static stiffness comparable. Sixty Pinus taeda L. trees, ranging from 14 to 19 years old, obtained from genetic tests established in the southeastern United States, were analyzed. Standing-tree acoustic velocities were measured using the TreeSonic tool. Acoustic velocities were also recorded in butt logs cut from the same trees using the Director HM200. A strong but biased relationship between tree and log velocities was observed, with tree velocities 32% higher (on average) than the corresponding log velocities. Two correction methods, one for calibrating tree velocities and one for accounting for differences in wood moisture content, were used to determine an adjusted MOE. After correction, adjusted MOE estimates were in good agreement with static longitudinal MOE values measured on clearwood specimens obtained from the trees, and no systematic bias was observed. The results of this study show that acoustic estimates of MOE on standing trees largely depend on how the data are processed and the reference method used. Des outils acoustiques sont de plus en plus utilises pour estimer la rigidite (dynamique) des arbres debout. Cependant, de telles mesures surestiment la rigidite statique, la technique standard pour determiner le module d'elasticite (MOE) du bois. Cette etude visait a identifier les methodes de correction des estimations sur les arbres debout pour rendre les valeurs de rigidite dynamique et statique comparables. Soixante tiges de Pinus taeda L. ont ete analysees. Elles etaient agees de 14 a 19 ans et provenaient de tests genetiques etablis dans le sud-est des Etats-Unis. La vitesse sonique dans les arbres debout a ete mesuree avec l'appareil TreeSonic. La vitesse sonique a aussi ete mesuree dans la bille de pied coupee chez les memes arbres avec le Director HM200. Une relation etroite mais biaisee a ete observee entre la vitesse sonique dans les arbres debout et les billes. La vitesse sonique etait en moyenne 32 % plus elevee dans les arbres que dans les billes. Deux methodes de correction ont ete utilisees pour determiner un MOE ajuste : une methode pour calibrer la vitesse sonique dans les arbres et une autre pour tenir compte de la difference d'humidite dans le bois. Apres avoir effectue la correction, les estimations du MOE ajuste correspondaient bien aux valeurs du MOE longitudinal statique mesure sur des echantillons de bois sain provenant des arbres et aucun biais systematique n'a ete observe. Les resultats de cette etude montrent que les estimations acoustiques du MOE chez les arbres debout dependent largement de la facon dont les donnees sont traitees et de la methode de reference utilisee. [Traduit par la Redaction], Introduction Mechanical properties are the most important wood characteristics for structural applications. Particularly important is the modulus of elasticity (MOE) or stiffness, which provides a measure of a wood member's [...]