White Spruce Wood Research Articles

Comparison between static modulus of elasticity, non-destructive testing moduli of elasticity and stress-wave speed in white spruce and lodgepole pine wood

ABSTRACT Static bending tests to measure modulus of elasticity (MOEST) or wood stiffness provide an indicator of the structural performance of a finished product. These tests are however, slow and expensive. Tests to measure MOE using non-destructive testing (NDT) provide alternatives to MOEST tests; however, relationships between the different modes of measurement need to be established. Non-destructive testing MOE measured by two methods (SilviScan [MOESS] and time of flight [MOETOF]) have been compared with MOEST for lodgepole pine and white spruce. The relationships between stress wave speed (SWS) and MOEST have also been evaluated. Simple linear regressions of MOESS, MOETOF, and SWS had greater explanatory power (higher coefficients of determination (R2)) than did multiple linear regressions including growth rate or other wood fibre attributes. Simple linear regression from MOETOF and MOESS on MOEST had lower R2 for lodgepole pine than for white spruce; however, the converse was true for SWS. SWS had the highest R2 (89%) and MOESS the lowest R2 (47%) when regressed on MOEST in lodgepole pine. The results were tool and species specific, suggesting that R2 between MOEST and non-destructive testing MOE values must be validated separately for each commercial tree species and for each measurement technique.

Improvement of White Spruce Wood Dimensional Stability by Organosilanes Sol-Gel Impregnation and Heat Treatment.

Wood is a living material with a dimensional stability problem. White spruce wood is a Canadian non-permeable wood that is used for siding applications. To improve this property, white spruce wood was treated with organosilanes sol-gel treatment with different moisture content (oven dried, air dried, and green wood). No major morphological changes were observed after treatment. However, organosilanes were impregnated into the cell wall without densifying the wood and without modifying the wood structure. Si-O-C chemical bonds between organosilanes and wood and Si-O-Si bonds were confirmed by FTIR and NMR, showing the condensation of organosilanes. The green wood (41% moisture content) showed only 26% dimensional stability due to the presence of too much water for organosilanes treatment. With a moisture content of 14%–18% (oven dried or air dried wood), the treatment was adapted to obtain the best improvement in dimensional stability of 35% and a 25% reduction of water vapor sorption. Finally, impregnation with organosilanes combined with the appropriate heat treatment improved the dimensional stability of white spruce wood by up to 35%. This treated Canadian wood could be an interesting option to validate for siding application in Canada.

Modelling wood density and modulus of elasticity in white spruce plantations in Eastern Québec

Forest managers have to take into account multiple objectives such as stand yield, wood quality attributes, ecological constraints and social considerations when making their decisions. The objective of the present study is to build (i) a dynamicmodulus of elasticity (MOEdyn) model and (ii) a core wood density (WDcore) model for white spruce plantations in theBas-Saint-Laurent Region (Québec, Canada) to quantify their inter- and intra-stand variations in order for managers tobetter weigh their different options. Using data obtained from 54 sample plots in 31 white spruce plantations from Eastern Québec, the MOEdynof 143 trees and the WDcoreof 162 trees were analysed. Dendrometric and stand variables wereused to build a MOEdynlinear mixed-effect model and a WD multiple linear regression model. The MOEdynmodel explained 66.8% of the total variation, 1.1% of which originated from inter-stand variations. MOEdynwas proportionalto diameter at breast height (DBH) and non-linearly decreased with tree growth rate. The WDcoremodel explained 16.0%of the total variation. The intra-stand variations were represented by a negative relationship between WDcoreand growthrate. Inter-stand variations were accounted for by site index and altitude. The performance of the MOEdynmodel was satisfactory and in accordance with the literature. However, the WDcoremodel was below standard, mainly as a consequenceof unaccounted intra-individual variations. Nonetheless, raw simulations using these models suggest that white sprucewood from plantations may benefit from intensive forest management.

White spruce wood quality for lumber products: priority traits and their enhancement through tree improvement

AbstractWhite spruce breeding has traditionally focused on genetic improvement for high productivity, targeting mostly stem volume. However, new challenges, such as the effects of climate change on individual trees and ecosystems and the changing nature of forest products markets, require action to address these issues while providing improved stock for seed and seedling production. This work aims to define the relative importance of white spruce wood traits for the lumber industry, with the intent of guiding tree breeding programs. This manuscript examines: (1) wood features that are important for lumber, (2) the genetics of wood traits and their improvement and (3) the level of acceptance of raw material with optimal traits, as obtained from a survey conducted with sawmills. Stem diameter at stump height, wood density, bending strength and stiffness were determined as the most important properties for sawmills. Decay proportion, knot diameter, slope of grain and the proportion of compression wood were also determined as important for sawmills, but to a lesser extent. Breeding efforts aiming to produce lumber should focus on stems with improved growth that are capable of sustaining the production of dense wood in greater proportion.

ORTHOGONAL CUTTING STUDY OF WOOD AND KNOTS OF WHITE SPRUCE

Wood defects can cause important loss of raw material and tooling during wood machining. White spruce (Picea glauca [Moench] Voss) is a wood species widely used in Canada, which presents an important occurrence of knots. These knots provoke several problems during machining affecting the final surface quality. The main objective of this research was to evaluate the orthogonal cutting forces and surface quality of white spruce wood with and without the presence of knots. Wood pieces of 12% MC were machined at four rake angles (10°, 20°, 30°, and 40°). Cutting forces and roughness were measured on clear wood (90°-0° cutting direction), knot (90°-90° cutting direction), and surrounding knot areas (before and after knot). Wood density in matched pieces were analyzed by X-ray densitometry. The results showed that the density of knots was in average 2.4 times higher than the density of clear wood. However, cutting forces of knots were up to eight times higher than those of clear wood. For all cutting areas, the parallel force increased as rake angle decreased. However, the sensitivity of cutting forces to changes in rake angle was higher for knots than for clear wood. Furthermore, surface roughness was positively correlated with the cutting forces. The rake angle of 40° produced the smaller cutting forces and lower surface roughness for clear wood, knots, and surrounding knot areas.

White Spruce Growth and Wood Properties over Multiple Time Periods in Relation to Current Tree and Stand Attributes

The relationships between white spruce radial increment and wood properties were investigated in relation to tree and stand attributes using data from mature white spruce stands in the boreal forest of western Canada that experienced a range of shelterwood treatments. The model with the highest predictive ability was radial increment (adj-R2 = 67%) and included crown attributes, diameter at breast height (DBH), average height of competitors, and a climate index. Radial growth was positively related to live crown ratio, whereas wood density and modulus of elasticity were negatively correlated to the crown attribute. Tree slenderness had a significant negative effect on wood density and modulus of elasticity, as it reflects the mechanical stability requirement of the tree. The models consistently improved when using annual averages calculated over longer periods of time. However, when the annual averages were calculated using time periods of 5–10 and 10–20 years prior to sampling, the predictive ability of the models decreased, which indicated that the current tree and stand conditions were the best predictors of growth and wood properties up to five years prior to sampling. This study suggests that crown length equal to 2/3 of the tree height might represent an optimal balance between radial growth and wood quality.

Variation in Trembling Aspen and White Spruce Wood Quality Grown in Mixed and Single Species Stands in the Boreal Mixedwood Forest

The Canadian boreal forest is largely represented by mixed wood forests of white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuloides Michx). In this study, a total of 300 trees originating from three sites composed of trembling aspen and white spruce with varying compositions were investigated for wood quality traits: one site was composed mainly of aspen, one mainly of spruce and a third was a mixed site. Four wood quality traits were examined: wood density, microfibril angle (MFA), fibre characteristics, and cell wall chemistry. Social classes were also determined for each site in an attempt to provide a more in-depth comparison. Wood density showed little variation among sites for both species, with only significant differences occurring between social classes. The aspen site showed statistically lower MFAs than the aspen from the mixed site, however, no differences were observed when comparing spruce. Fibre characteristics were higher in the pure species sites for both species. There were no differences in carbohydrate contents across sites, while lignin content varied. Overall, the use of social classes did not refine the characterization of sites.

Analytical pyrolysis of hot water pretreated forest biomass

Fast pyrolysis is a promising technology to promote wood biomass utilization. This thermochemical process produces mainly a liquid bio-oil. Currently, a direct application of bio-oil as fuel is limited due to its poor physicochemical properties.Pressurized Hot Water Treatment (PHWT) has been applied on white spruce and trembling aspen whole wood chips prior to production of pyrolysis oil. The effect of PHWT and the influence of the fast pyrolysis parameters on the bio-oil composition and products distribution were investigated by analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py–GC/MS), it was carried out at two heating rates (100°C/min and 1000°C/min) and in temperature ranges from 350°C to 500°C for trembling aspen and from 400°C to 550°C for white spruce. The pyrolysis products were identified to belong to eleven chemical groups: syringyl derivatives, guaiacyl derivatives, other phenolics, anhydrosugars, low molecular weight acids, fatty acids, furans, pyrans, ketones, aldehydes and alcohols.The results of the analytical pyrolysis indicate that the higher yield is obtained from pretreated than from untreated biomass. The effect of the pretreatment is more important for the 1000°C/min heating rate than for 100°C/min. The composition analysis revealed that the higher peak area% of anhydrosugar were obtained from PHWT biomass at 1000°C/min while the phenols were the major constituents of the pyrolysis products obtained at lower, 100°C/min heating rate. It is also demonstrated that the acids are still found in pyrolysis products even after pretreatment. The Py–GC/MS results obtained in this study indicate that pretreatment affected the hardwood and softwood in quite different ways.

Genetic control of wood properties in Picea glauca — an analysis of trends with cambial age

We investigated the genetic control of wood properties as a function of cambial age to enable improvement of juvenile wood attributes in white spruce ( Picea glauca (Moench) Voss). Increment cores were taken from 375 trees randomly selected from 25 open-pollinated families in a provenance–progeny trial repeated on three sites. High-resolution pith-to-bark profiles were obtained for microfibril angle (MFA), modulus of elasticity (MOE), wood density, tracheid diameter and cell wall thickness, fibre coarseness, and specific fibre surface with the SilviScan technology. Heritability estimates indicated that genetic control of cell anatomy traits and wood density increased with cambial age, whereas the genetic control of MFA and MOE remained relatively low across growth rings. Wood density, radial cell diameter, cell wall thickness, and specific fibre surface were highly heritable, indicating that significant genetic gains could be expected in tree improvement programs, although cambial age at selection may strongly influence the magnitude of realized gains. In contrast, growth-related properties, such as ring width, core length, and tree height, gave weak or nonsignificant heritability estimates. Adverse correlations between mechanical strength and properties related to paper quality suggest that breeding strategies must incorporate both types of traits to improve white spruce wood quality for different end uses.

Cantilever experimental setup for rheological parameter identification in relation to wood drying

Wood exhibits a pronounced time dependent deformation behavior which is usually split into ‘viscoelastic’ creep at constant moisture content (MC) and ‘mechano-sorptive’ creep in varying MC conditions. Experimental determination of model rheological parameters on a material level remains a serious challenge, and diversity of experimental methods makes published results difficult to compare. In this study, a cantilever experimental setup is proposed for creep tests because of its close analogy with the mechanical behavior of wood during drying. Creep measurements were conducted at different load levels (LL) under controlled temperature and humidity conditions. Radial specimens of white spruce wood [Picea glauca (Moench.) Voss.] with dimensions of 110 mm in length (R), 25 mm in width (T), and 7 mm in thickness (L) were used. The influence of LL and MC on creep behavior of wood was exhibited. In constant MC conditions, no significant difference was observed between creep of tensile and compressive faces of wood cantilever. For load not greater than 50% of the ultimate load, the material exhibited a linear viscoelastic creep behavior at the three equilibrium moisture contents considered in the study. The mechano-sorptive creep after the first sorption phase was several times greater than creep at constant moisture conditions. Experimental data were fitted with numerical simulation of the global rheological model developed by authors for rheological parameter identification.

Comparison between 10,000-year old and contemporary spruce lignin

Wood from white spruce Picea glauca that had been preserved by rapid burial in lake sediments 10,000 years ago, was investigated and compared to a contemporary reference white spruce wood. The 10,000-year old sample appeared to have an intact primary cell wall and middle lamella, whereas the carbohydrate monomer distribution, and microscopic images showed that the secondary wall was at least partially removed, indicating that this structure had been selectively attacked by bacteria. The Klason lignin amount in the aged spruce was found to be 60%. The relative lignin monomer content in the aged spruce was 9% lower than that of the reference wood, showing that there were fewer β-O-4′ linkages in the aged sample. This finding was supported by SEC analysis of the thioacidolysed samples as a larger proportion of lignin oligomers were observed in the aged spruce than in the reference material. This indicates a somewhat greater number of condensed bonds in the aged spruce than in the reference spruce sample. Quantitative 13C NMR analysis and HSQC techniques applied on milled wood lignins (MWL) revealed no significant structural differences between the aged spruce and the reference.

Heritability and genetic correlations of wood characters of Upper Ottawa Valley white spruce populations grown in Quebec

The degree of inheritance and the genetic correlations of white spruce wood characters were studied from 39 half-sib families of eight populations from the Upper Ottawa Valley, 19 years after planting. The results indicated that these characters differ significantly among half-sib families. Furthermore, the study showed that white spruce wood characters are genetically related. Strong genetic correlations exist between the characters of inner wood and those of outer wood. Moderate to strong genetic control of outer wood characters was found while inner wood characters were found to be much more influenced by environmental factors. Expected genetic gains from a sequential two-step selection strategy were calculated.

Effect of water in the carbon-13 CP/MAS NMR spectrum of white spruce wood

Effect of water in the carbon-13 CP/MAS NMR spectrum of white spruce wood

Variabilité de la densité du bois et de la production des provenances d'épinette blanche, 20 ans après plantation

The variability of wood specific gravity and yield of 23 white spruce provenances from the Great Lakes – St. Lawrence forest region was studied 20 years after planting at Harrington Forest Farm, Québec. The results indicate no relationship between wood specific gravity of provenances and their respective growth performance. The southwestern section of this region showed a small decrease in wood specific gravity, but it was compensated for by a strong increase in volume growth, resulting in an important gain in dry weight productivity. The variability of white spruce wood specific gravity was split into three sources: 11% was attributed to provenance differences, 8% to provenance and repetition interaction, and the remainder to differences among trees of the same provenance and to experimental error. In a breeding program, a first selection should be made at the provenance level on the basis of volume productivity and a second selection on the basis of wood specific gravity values within the selected provenances, to maximize the overall genetic and economic gain.

An immersion technique for studying wood wettability

The wetting properties of wood were studied by a modification of the Wilhelmy technique. This method involved continuously monitoring the force exerted on a wood specimen as it was immersed at a controlled rate into a liquid. Wettability was expressed in terms of the area under the force-immersion curve and was referred to in this study as “wettability index”. The applicability of the technique was demonstrated for padauk and white spruce wood specimens heated for various time periods. The wettability of these woods in both distilled water and sodium hydroxide solutions decreased with increasing heating time. Sodium hydroxide solution yielded higher wettability index values, indicating that it was a better wetting agent than distilled water. The pH of the sodium hydroxide solution had a strong influence on magnitude of the wettability index. The possibility of using the technique for examining wood surface inactivation in relation to bonding with different adhesives is discussed.

Perforation hyphae of soft rot fungi in the wood of white spruce [Picea glauca (Moench.) Voss.

Observations made on ponded white spruce wood with the electron microscope revealed that initial branching of perforation hyphae of soft rot fungi did not parallel microfibrillar orientation in the S2 wall layer but rather occurred perpendicular to this alignment. In the absence of structural evidence suggesting mechanical entry it appeared that cell wall pencetration was accomplished through enzymatic activity at the hyphal apex.

URONIC ACIDS FROM WHITE SPRUCE (PICEA GLAUCA (MOENCH) VOSS)

Acid hydrolysis of extractive-free white spruce wood produced a number of neutral and acidic sugars and oligosaccharides. The acidic components were isolated and three of these were shown to be 4-O-methyl-D-glucuronic acid, 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylose, and tentatively O-(4-O-methyl-α-D-glucopyranosyluronic acid)-(1→ 2)-O-β-D-xylopyranosyl-(1→ 4)-D-xylopyranose.

STRUCTURE OF AN ARABOGALACTAN FROM WHITE SPRUCE (PICEA GLAUCA (MOENCH) VOSS)

A water-soluble polysaccharide isolated from white spruce wood contained D-galactose, L-arabinose, and D-xylose in a molar ratio of 21:3:1. Hydrolysis of the fully methylated polysaccharide yielded 2,3,5-tri-O-methyl-L-arabinose (12 moles); 2,3,4,6-tetra-O-methyl-D-galactose (29 moles); 2,3,4-tri-O-methyl-D-galactose (34 moles); 2,6-di-O-methyl-D-galactose (0.5 moles); 2,4-di-O-methyl-D-galactose (45 moles); 2,3-di-O-methyl-D-xylose (5 moles); and monomethyl xylose (1 mole). When oxidized by periodate the polysaccharide consumed 1.18 moles of oxidant, and yielded 0.56 moles of formic acid per mole of anhydro-D-galactose. The D-xylose was attributed to the presence of a xylan mixed with the arabogalactan in the original polysaccharide preparation. The methylation and periodate oxidation data showed that the arabogalactan possessed a highly branched structure with the anhydro-D-galactose units being joined by 1 → 3 and 1 → 6 glycosidic bonds. All of the L-arabinose was present in the furanoside form as non-reducing terminal units.

Some of the Products Obtained in the Hydrolysis of White Spruce Wood with Dilute Sulfuric Acid under Steam Pressure.

Some of the Products Obtained in the Hydrolysis of White Spruce Wood with Dilute Sulfuric Acid under Steam Pressure.