Wood Stiffness Research Articles

Mid-infrared spectroscopy and dynamic mechanical analysis of heat-treated obeche (Triplochiton scleroxylon)wood

The chemical structure change and rheological behaviour of heat-treated Obeche (Triplochiton scleroxylon) wood were investigated. Wood samples were treated at 160 and 200°C for 30, 60 and 120 minutes. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and dynamic mechanical analysis (DMA) were employed to characterize the chemical structure and rheological property of the heat-treated wood, respectively. Infrared data showed that there was a reduction in the number of hydroxyl groups (one of the factors normally attributed to water absorption) of heat treated wood relative to the control samples. The relative cellulose crystallinity increased slightly which may be one of the factors contributing to the stiffness of the heat-treated wood. The latter increases with increasing treatment temperature and time. The rheological properties of the wood samples were tested while submerged in N-methyl-2-pyrrolidone solvent under saturated conditions. DMA results showed that the increasing heat treatment time caused an increase in the glass transition temperature relative to the control sample, irrespective of the treatment temperature. Therefore, heat treatment at moderately high temperatures (160 and 200 °C) showed an interesting potential which could be used to reduce water absorption and improve flexural modulus of Obeche wood.

Effects of site, silviculture and seedlot on wood density and estimated wood stiffness in radiata pine at mid-rotation

To understand the underlying control of patterns of important wood properties is fundamental to silvicultural control of wood quality and genetic selection. This study examines the influences of site, silviculture and seedlot on diameter growth, wood density and estimated wood stiffness in mid-rotation radiata pine (Pinus radiata D Don) stands across New Zealand. Selected treatment combinations were assessed across five sites in a 17-year-old experiment comparing silvicultural treatments and improved breeds of radiata pine. Diameter at breast height (DBH), and stress-wave velocity (an indicator of wood stiffness) and outerwood (outermost five growth rings) basic density at breast-height were assessed for ten trees from each plot in the experiment. There were large differences in DBH and wood properties between sites. Silviculture (stand density) had a stronger influence than seedlot on DBH and stress-wave velocity, while the converse applied to outerwood density. There was a positive relationship between stand density and both stress-wave velocity and outerwood density. Trees in the un-pruned 500 stems ha−1 treatment had larger DBH, lower outerwood density and lower stress-wave velocity than trees in the 400 stems ha−1 pruned treatment. This suggests that silvicultural manipulation (pruning) of green crown length is important for controlling both growth and wood properties. Results from this study support previous research which indicates that thinning, and to a lesser extent pruning, have a strong impact on DBH, stress-wave velocity and outerwood density. Increasing stand density is consistently associated with stiffer and denser outerwood.

Genetic relationship between wood properties and growth traits in Larix kaempferi obtained from a diallel mating test

Knowledge of the genetic relationship between growth traits and wood properties is critical for their simultaneous genetic improvement. We measured the height and diameter at breast height (DBH) and wood quality traits, including stress wave velocity (SWV) as the selection criteria for wood stiffness, wood density, and Pilodyn penetration depth as selection criteria for wood density, at a progeny test site at stand age ca. 30, which comprised of full-sib families by a full diallel mating design with eight plus Larix kaempferi tree clones. We estimated the genetic parameters for each trait and phenotypic, genetic and residual correlation between traits. The contribution of specific combining ability and reciprocal effects were small for all traits. Growth traits showed high positive genetic correlation with average wood density of the outermost five rings (0.912 for height, 0.826 for DBH) and with SWV (0.738 for height, 0.762 for DBH), irrespective of small phenotypic correlations between them. Wood density and SWV also showed high genetic correlation. Pilodyn penetration depth showed high selection efficiency for average wood density of the outermost five rings (79.8 %) whereas SWV showed higher selection efficiency for wood density. Thus, simultaneous genetic improvement of growth traits and wood properties of L. kaempferi appears possible.

Modelling microfibril angle variation in New Zealand-grown radiata pine

Microfibril angle (MFA) is a property of wood cell walls that has a strong influence on end-product quality, particularly for solid timber. Forest managers, tree breeders and wood processors require more quantitative information on the inter- and intra-stem variation in MFA in order to understand the impacts of their decisions on wood quality. The aim of this study was to develop parametric models that can be used to predict the intra- and inter-stem variation in MFA in radiata pine (Pinus radiata D. Don) trees growing in New Zealand Empirical models were developed using a dataset that contained records from 347 trees in which radial profiles of MFA have been measured at different heights up the stem. Radial variation in MFA was modelled as a function of cambial age using both a modified logistic function and a modified Michaelis-Menten equation. Additional terms were added to these models to account for differences in MFA with relative height up the stem. Values of MFA ranged from more than 40° near the pith to approximately 10-15° in the outerwood. Values greater than 30° were largely confined to the inner rings of the butt logs. A variance components analysis showed that most of the variation in MFA occurred within stems, with less than 15% of the variation due to differences between sites. The final models were able to account for 57-63% of the variation in MFA and inclusion of a relative height term significantly improved the model fit. Radiata pine has a region of high microfibril angle in the first 10-15 growth rings from the pith, particularly at the base of the tree. Growth rate had a small positive influence on average MFA (wider rings resulting in higher MFA values). Site differences were small, indicating that regional variation in wood stiffness is due more to the known trends in wood density. The models developed here can be coupled to growth models to examine how the combination of site productivity and silvicultural regime affect the size of the central zone containing high MFA wood.

Lumber and wood chips properties of dead and sound black spruce trees grown in the boreal forest of Canada

Little attention has been given to changes in wood properties after isolated mortality events, which characterize the gap dynamics of several forest ecosystems. For the forest industry, dead and sound trees may represent a significant source of timber supply, but of potentially lower quality. The main objective of this study was therefore to compare the properties of wood obtained from dead and sound wood (DSW) trees with those from live trees. In total, 162 black spruce trees (Picea mariana (Mill.) BSP) were felled from three sites comprising three states of tree degradation and three diameter classes. In total, 822 pieces of lumber of different dimensions were produced and visually graded. Full-size lumber pieces of 4.3–5.0 m in length (n 1⁄4 343) were tested for wood stiffness and strength in longitudinal static bending. Samples of wood chips and bark were also collected during the production process at a sawmill. Results indicate that DSW trees produced lumber of significantly poorer mechanical properties than live trees. For the same modulus of elasticity (MOE) value, DSW trees have significantly lower modulus of rupture values than those of live trees, especially for MOE values of ,15 GPa. This suggests that the wood of DSW trees is more brittle, a fact that should be taken into account for the production of machine-stress-rated lumber. Moisture content of wood chips was significantly lower in DSW trees, although it remained above the fibre saturation point. The amount of wood fibre attached to the bark was significantly higher in DSW trees. Considering these differences, DSW trees can be expected to provide wood of inferior quality than live trees but which still meet the technical requirements (Barrett and Lau, 1994) for producing structural lumber.

Influence of moisture on the vibro-mechanical properties of bio-engineered wood

In this study, changes in the vibro-mechanical properties of fungi-treated wood, during sorption and desorption at different humidity levels, were investigated. Norway spruce resonance wood (with uniform narrow annual rings and high tonal quality for musical instrument craftsmanship) was incubated with Physisporinus vitreus for 36 weeks. Stiffness, internal friction, and tonal performance indices of control (untreated) and fungi-treated wood were compared after exposure to a stepwise variation of relative humidity. It was demonstrated that fungal treatment increased the internal friction and decreased the specific modulus of elasticity, during reduction of wood density. Internal friction of both control and fungi-treated wood significantly increased during dynamic sorption, especially during early stages (hours) of each humidity change step. Both specific modulus of elasticity and internal friction showed a hysteretic behavior during humidity variation cycles. Hysteresis was smaller in fungi-treated wood. Also, tonal performance indices were improved after fungal treatment and showed a reduced variation at different relative humidity conditions. Dynamic vapor sorption tests and FT-IR microscopy studies revealed changes in hygroscopicity and the supramolecular structure of wood, which may explain the observed vibrational behavior. Less dependency of wood vibrational properties to the variation of the ambient humidity is important for the acoustic performance of string instruments.

Incorporating non-key traits in selecting the Pinus radiata production population

Three of the traits considered of most economic importance in the genetic improvement of Pinus radiata D. Don, termed as ‘key’ traits, are tree diameter (a proxy for stem volume), wood density and wood stiffness. A number of other traits (non-key traits) may be of equal importance to growers depending on where and for what purpose the trees are being grown. Two such non-key traits are: resistance to the needle blight caused by Dothistroma septosporum (Dorog.) M. Morelet, and reduced heartwood content. Data from two trial series (each planted at two sites, from a total of some 330 families (189 were half-sib and 142 were full-sib) with 10 to 30 individuals assessed per family) were analysed to determine the effect forwards selection of key traits had upon genetic gains of these two non-key traits. Multivariate analysis for each trial provided estimates of trait narrow-sense heritabilities (h2) and genetic correlations between traits. Density was the most heritable trait assessed (ĥ2 0.50 to 0.72) with heartwood ring number (0.21 to 0.35), acoustic velocity (0.40), resistance to Dothistroma septosporum (0.20 to 0.34) and stem diameter (0.11 to 0.25) being less heritable. Wood properties were adversely correlated with growth rate to varying degrees. To estimate the impact of differing technical weights on multiple traits a selection index model was used. Strong positive genetic correlations (r g 0.69 to 0.87) between resistance to Dothistroma septosporum and stem diameter means that strong selection for stem diameter after severe Dothistroma attack assures genetic gain in resistance to Dothistroma septosporum. Strong selection for stem diameter compromised wood properties due to adverse correlations between the two. Heartwood ring number was almost uncorrelated with the other key traits, density and stiffness, meaning that zero or slight negative gain would be expected via indirect selection. In such instances, it is advocated that key traits be selected for in the breeding population using a selection index and that non-key traits such as heartwood be selected using independent culling in the production population.

Propriedades físico-mecânicas do lenho deteriorado por fungos apodrecedores de árvores de Tipuana tipu

A tipuana (Tipuana tipu) foi muito utilizada na arborização urbana. De maneira geral, o manejo inadequado expõe o lenho à ação dos fungos e insetos xilófagos, muitas vezes associados à queda da árvore. Portanto, com este trabalho, objetivou-se caracterizar as propriedades físico-mecânicas do lenho sadio e biodeteriorado por fungos apodrecedores em árvores de tipuana da arborização urbana da cidade de São Paulo-SP. Treze árvores com deterioração no lenho foram suprimidas. Da base do tronco foram cortados toretes de 1 m de comprimento para a caracterização das propriedades físico-mecânicas dos lenhos sadio e deteriorado. Os resultados indicaram que, por meio do perfil radial de densidade por densitometria de raios X, foram identificados sete padrões de biodeterioração do lenho, sendo, (EXS) com acúmulo de extrativos e sadio, (ZR) com zona de reação e sadio, (NS) normal e sadio, (PB INC; PB INT) podridão branca incipiente ou intensa e (PM INC; PM INT) podridão mole incipiente ou intensa, com densidades 0,94, 0,92, 0,82, 0,66, 0,41, 0,67 e 0,44 g.cm-3, respectivamente. Os ensaios mecânicos evidenciaram os lenhos (ZR) (EXS) com os maiores valores de resistência e rigidez de 84 e 80 MPa e 6461 e 5826 MPa, respectivamente; o lenho (NS) apresentou valores de 62 e 4642 MPa e os padrões (PB INC) (PM INT) os menores e significativos valores de resistência e rigidez, destacando o (PB INT) com valores de 5 e 571 MPa. A redução dos valores de densidade, resistência e rigidez do lenho esteve relacionada com a biodeterioração da parede celular das células das árvores de tipuana pelos fungos apodrecedores.

Early genetic selection for wood stiffness in juvenile Douglas-fir and western hemlock

Wood stiffness, or modulus of elasticity (MOE), is an important property of structural wood products. The ability to genetically improve wood stiffness has increased because of the availability of tools that can measure acoustic velocity (AV, an indirect measure of MOE) on standing trees. Our goals were to optimize methods for measuring AV on young (6- to 12-year-old) Douglas-fir and western hemlock, and then use these methods to understand the genetics of wood stiffness. In Phase I, we evaluated four standing-tree tools (TreeSonic-TS, TreeSonic-SD02, Microsecond Timer, and Ultrasonic Timer) by comparing AV2 measured on standing trees to AV2 measured on logs cut from these trees (i.e., using the HM200). We found that measuring across a whorl of branches had little adverse effect on AV measurements, and that placing the acoustic sensors on the same-face of the tree was slightly better than placing them on opposite faces. In Phase II, we used full-sib heritabilities (hfs2) to compare the TreeSonic-SD02 and Microsecond Timer, sensor orientations (same-face versus opposite-face), and flight path adjustments. Because the effect of standing-tree tool and sensor orientation was non-significant, we recommend that breeders use the TreeSonic-SD02 and same-face orientation for practical reasons. Using this approach, hfs2 for AV2 was 0.90 to 0.56 in Douglas-fir and 0.51 in western hemlock, and we concluded that genetic gains of 7.0–17.2% can be obtained by measuring 10 or more trees per full-sib family, depending on species and seed production strategy. Because we found no strong statistical support for substantial non-additive genetic variation, the current approach of breeding for additive genetic value, and then collecting open-pollinated seed from orchards seems appropriate for improving wood stiffness. AV2 had weak genetic correlations with growth traits (height, diameter at breast height, and volume) in Douglas-fir (−0.21 to 0.33), but moderately positive correlations in western hemlock (0.36–0.54). Therefore, there is ample opportunity to improve the stiffness of young trees without adversely affecting growth. Although mean stiffness was higher for Douglas-fir, about 10% of the western hemlock families (7 out of 80) had higher AV2, and about 28% of the families (22 out of 80) had higher dynamic MOE than the mean for Douglas-fir. This suggests that intensive selection and breeding in western hemlock could be used to create varieties of trees that compare favorably with unselected Douglas-fir. This may improve the ability of western hemlock to compete with Douglas-fir where stiffness is important.

An Overview of Microfibril Angle in Fiber of Tension Wood

The angle between helical windings of microfibrils in the secondary cell wall of fibers and the long axis is called microfibril angle (MFA). Stiffness of wood depends on variations in the MFA. The large MFA shows low stiffness, which is found in juvenile wood and this character make threes vulnerable to high winds breaking. Timber containing a high proportion of juvenile wood is unsuitable for use as high-grade structural timber. On the other hand, the small MFA in wood shows high stiffness, which has importance in a good view of the trend in forestry. The timber with high stiffness is commonly high economic value. They are grown mainly for construction, timber and furniture. Until date, it is under pressure for increased timber production means that ways will be sought to improve the quality of timber by reducing MFA. Commonly, MFA decrease during the formation of tension wood therefore study on tension wood related to MFA formation is important for MFA reduction in normal wood. The study on tension wood formation could predict expression patterns of genes/proteins for reduction of MFA. Herein, the orientation of microfibril and MFA in cell wall layers of normal and tension wood fiber are discussed.

Structure–function relationships in hardwood – Insight from micromechanical modelling

A micromechanical model is presented that predicts the stiffness of wood tissues in their three principal anatomical directions, across various hardwood species. The wood polymers cellulose, hemicellulose, and lignin, common to all wood tissues, serve as the starting point. In seven homogenisation steps, the stiffnesses of these polymers are linked to the macroscopic stiffness. The good agreement of model predictions and corresponding experimental data for ten different European and tropical species confirms the functionality and accuracy of the model.The model enables investigating the influence of individual microstructural features on the overall stiffness. This is exploited to elucidate the mechanical effects of vessels and ray cells. Vessels are shown to reduce the stiffness of wood at constant overall density. This supports that a trade-off exists between the hydraulic efficiency and the mechanical support in relation to the anatomical design of wood. Ray cells are shown to act as reinforcing elements in the radial direction.

Wood as a natural smart material

The dominant feature of artificial smart materials is the “shape memory” effect. This phenomenon is based on frozen strains (FS). They were detected in wood fastened specimens during drying in the early 1960s. The integral law of wood deforming under loading and moisture content and/or temperature changes was subsequently formulated. This law takes into account the forming of FS. It was applied for the calculation of wood drying stresses. Stress memory and strain memory effects for wood were discovered. Wood has the ability to recollect the type of loading (tension or compression) which it had undergone. The difference between the free and restrained shrinkage is named “frozen shrinkage” (FSh). In calculations of drying stresses, it is more justified to use the FSh concept than “mechano-sorptive creep” (MSC). The MSC phenomenon is observed at cyclical change of moisture content in loaded wood. “Hygrofatigue” that reduces wood stiffness plays the main role in this process.

Effects of biodegradation by brown-rot decay on selected wood properties in eastern white cedar (Thuja occidentalis L.)

The effects of decay on wood density, wood structure, chemical composition, and mechanical properties in eastern white cedar (Thuja occidentalis L.) were investigated. Decay stage was determined by X-ray densitometry and scanning electron microscopy (SEM). Chemical and mechanical properties of decayed and sound wood samples were also determined. SEM results showed that decay colonization varied among wood cell types and within individual cell wall layers. Growth of fungi causing brown rot decay was limited and slower in latewood than in earlywood due to the narrow cell lumen, thicker wall, and higher density of latewood. Decay-related changes in wood density were more prominent in earlywood than latewood tracheids. Brown-rot decay selectively removes structural carbohydrate components, increasing the higher lignin/carbohydrate ratio as decay progresses. The relationships between chemical composition, mechanical properties, and weight loss were highly significant, with 15% weight loss leading to 40% loss in modulus of rupture (MOR) and 30% loss in bending modulus of elasticity (MOE). The strength loss (MOR) was attributable to arabinan and galactan loss. The loss in wood stiffness was associated with cellulose (glucan) loss, and weight loss was associated with mannan and xylans losses.

Magnesium fertilizer, weed control and clonal effects on wood stiffness of juvenile Pinus radiata at two contrasting sites

Two field trials established at contrasting sites (Kaingaroa and Rolleston) with different silvicultural treatments [magnesium (Mg) fertilizer or plus or minus weed control (±WC)] but identical clones of Pinus radiata were measured at age 6 for tree height (Ht), diameter at breast height (DBH) and ground-line (GLD), and modulus of elasticity (MOE) of standing trees. This study was undertaken to (i) quantify the main and interactive effects of clone, site, Mg fertilizer or WC on stem slenderness and corewood MOE of juvenile radiata pine, and (ii) examine the relationships between clonal means of corewood MOE and stem slenderness from 15 selected clones.At the Kaingaroa site, clone had a significant (P<0.001) influence on stem slenderness and corewood MOE, which exhibited a 1.5-fold variation (1.48–2.33GPa). The Mg fertilizer effect on MOE was not significant. At the Rolleston site, both WC and clone had significant (P<0.001) influence on corewood MOE. Compared to −WC, +WC reduced MOE by 7%. The MOE exhibited a 1.7-fold variation (1.67–2.83GPa) among the 15 clones. Across both sites, MOE exhibited a 1.5-fold variation (1.65–2.55GPa) among the 15 clones. Overall, clonal differences in MOE were substantial and larger than the differences due to site and WC. Significant interactions were also found between clone and Mg fertilizer, clone and WC, and clone and site.This study for the first time showed the clonal means of MOE was strongly and positively correlated to clonal means of stem slenderness. This study has the important implication for forest managers that clonal material can be closely matched to site conditions and management regimes to optimise product value.

Prediction of dry veneer stiffness using near infrared spectra from transverse section of green log

This study examined the feasibility of near infrared spectroscopy as a novel technique for log assessment on the basis of wood property. Near infrared (NIR) spectra were obtained from the transverse section of green log and multivariate regression analysis was carried out to predict the stiffness of veneer processed from the log. The stiffness of the veneer was dynamic modulus of elasticity measured using ultrasonic method. The calibrations of veneer stiffness had moderate relationships between measured and NIR-predicted values, with regression coefficients ranging from 0.84 to 0.88. The calibration equations were applied to the test set and it was found that predictions were also well fitted, with regression coefficients ranging from 0.67 to 0.89. The results indicate that the variation of wood stiffness within the logs could be assessed using the NIR spectra from the cross-section of logs. The spectra were obtained from green condition of the log and the stiffness of veneer was measured after kiln drying. Thus, the results imply that the wood stiffness in dry condition could be predicted using the spectra collected from green logs. If the models obtained in this study put into the imaging system, the two-dimensional map of the stiffness would be visualized on the cross-section of logs. The NIR spectroscopy coupled with imaging system could compensate the weak point of the traditional methods for log assessment.

A DEA approach to assess the efficiency of radiata pine logs to produce New Zealand structural grades

Abstract An efficiency analysis revealed the relative magnitude of wood traits that distinguishes efficient radiata pine logs to produce New Zealand structural grades. Technical and cost efficiencies were obtained by using data envelopment analysis (DEA). Wood trait prices used to perform the cost efficiency corresponded to economic weights derived from a partial regression. These values were 1.1, 29.7, 0.3 and −0.4 NZ $/m 3 for small end diameter (cm), stiffness (GPa), basic density (kg/m 3 ) and largest branch (mm) respectively. The most efficient logs were those with the highest difference between recovery value and price. There were positive and significant correlations between technical efficiency and wood stiffness (0.46, p p

Using a production approach to estimate economic weights for structural attributes of Pinus radiata wood

We modeled the technical relationships between volume of Pinus radiata D. Don structural lumber (with stiffness>8 GPa) and log attributes using a stochastic frontier approach. The production models were Cobb–Douglas and Translog, while the log attributes were small end diameter (SED), wood stiffness (STF), and largest branch (LBR); however, the effect of the latter trait was not significant (p>0.05). Economic values of log traits were represented by their values of marginal product (VMP). The coefficients for the Cobb–Douglas frontier were statistically significant and the model met most of the production theoretical properties. VMP derived from the Cobb–Douglas were 2.23 NZ$/cm for SED and 16.88 NZ$/GPa for STF. The Translog frontier coefficients were also significant (p<0.05) and VMP derived from this model were 1.67 NZ$/cm for SED and 9.15 NZ$/GPa for STF. Thus, for the analyzed production stage, changes to SED and STF were relevant for improving log value recovery above MSG8+. Technical efficiency derived from the frontiers allowed to identify and characterize the best logs to produce structural grades with stiffness of 8 GPa or higher.

Quantifying the influence of live crown ratio on the mechanical properties of clear wood

Conceptual models of wood formation suggest that trees with large crowns produce wood with reduced mechanical properties due to enhanced auxin production, but few studies have explicitly examined the relationship between crown dimensions and wood properties. Using white spruce (Picea glauca (Moench) Voss) trees harvested from spacing and thinning trials in central Ontario, Canada, this study examines how live crown ratio influences the strength and stiffness of wood. Modulus of rupture (MOR) and modulus of elasticity (MOE) were measured by conducting three-point bending tests on small (150 ×10×10 mm) defect-free samples selected from different radial positions at three heights within the stems. MOR and MOE were strongly and positively related to cambial age, and also increased slightly with sampling height. In addition, MOR showed a significant decrease with increasing live crown ratio ‐ calculated as the ratio of crown length to tree height ‐ in both the spacing and the thinning trials. However, MOE decreased significantly with live crown ratio only in the spacing trial, where the younger trees had a larger range of crown ratios. These results provide tentative support for models of wood formation that link wood quality with crown development, suggesting that crown metrics could be used to predict wood properties before harvest, but doing so may be problematic in mature stands that exhibit less variability in crown dimensions.

Economic Analysis of a Pine Plantation Receiving Repeated Applications of Biosolids

Treated biosolids have been applied to 750-ha of a Pinus radiata forest plantation on Rabbit Island near Nelson City in New Zealand since 1996. A long-term research trial was established in 1997 to investigate the effects of the biosolids applications on the receiving environment and tree growth. An analysis of the likely economic impact of biosolids application shows that biosolids application has been beneficial. Stem volume of the high treatment (biosolids applied at 600 kg N ha-1 every three years) was 36% greater than the control treatment (no biosolids applied), and stem volume of the standard treatment (300 kg N ha-1) was 27% greater than the control treatment at age 18 years of age. Biosolids treatments have effectively transformed a low productivity forest site to a medium productivity site. Although this increased productivity has been accompanied by some negative influences on wood quality attributes with reduced wood stiffness, wood density, and larger branches, an economic analysis shows that the increased stem volume and greater average log diameter in the biosolids treatments outweighs these negative effects. The high and standard biosolids treatments are predicted to increase the net stumpage value of logs by 24% and 14% respectively at harvesting, providing a large positive impact on the forest owner’s economic return.

Evaluation of Stiffness and Strength of Scots Pine Wood Using Resonance Frequency and Ultrasonic Techniques

The aim of this paper was to predict the static bending modulus of elasticity (MOES) and modulus of rupture (MOR) of Scots pine (Pinus sylvestris L.) wood using three nondestructive techniques. The mean values of the dynamic modulus of elasticity based on flexural vibration (MOEF), longitudinal vibration (MOELV), and indirect ultrasonic (MOEUS) were 13.8, 22.3, and 30.9 % higher than the static modulus of elasticity (MOES), respectively. The reduction of this difference, taking into account the shear deflection effect in the output values for static bending modulus of elasticity, was also discussed in this study. The three dynamic moduli of elasticity correlated well with the static MOES and MOR; correlation coefficients ranged between 0.68 and 0.96. The correlation coefficients between the dynamic moduli and MOES were higher than those between the dynamic moduli and MOR. The highest correlation between the dynamic moduli and static bending properties was obtained by the flexural vibration technique in comparison with longitudinal vibration and indirect ultrasonic techniques. Results showed that there was no obvious relationship between the density and the acoustic wave velocity that was obtained from the longitudinal vibration and ultrasonic techniques.