Four Picea glauca (Moench) Voss trees grown at each of four square spacing intensities between trees: 1.2 m, 1.8 m, 4.3 m, and 6.1 m in a plantation established in 1967 in the Petawawa Research ...Forest, Ontario, Canada (lat. 45.59° N, long. 77.25° W, elev. 168 m) and sampled at four different heights (1.3 m, 4.3 m, 7.3 m, 10.3 m) were used to study the impact of spacing between trees and sampling height on nine wood quality attributes (ring width, ring density, tracheid length, tracheid diameter, latewood proportion, intra-ring density variation, ring area, earlywood width, and latewood width). In the juvenile wood, ring width was wider and ring density higher than in the mature wood. Tracheid length was longer and tracheid diameter wider in the mature wood compared to the juvenile wood. The variation of ring density between the two wood zones was limited, and latewood proportion did not show any difference with wood zone. Sampling height induced variation in more wood quality attributes than did spacing. Except for growth rate, spacing between trees did not significantly impact wood quality attributes. Most of these variations were registered between widely different spacings.
The radial variation was examined for tracheid lengths of Norway spruce (Picea abies (L.) Karst.), European larch (Larix decidua Mill.), and Scots pine (Pinus sylvestris L.) wood from dominant trees ...coming from an even-aged stand, and growing under identical forest site and climatic conditions. The measurements were completed on macerated material. The variation of tracheid lengths in annual rings from the core to the bark was used for determination of the border between the juvenile and mature wood in the trunk cross-section. The boundary age between the juvenile and mature wood zones established for the examined species was comparable, as it was 25 annual rings for Scots pine and 29 for European larch and for Norway spruce. In the juvenile zone, the tracheid lengths increased 2.2-fold in Norway spruce wood, while in Scots pine and European larch wood it was approximately 1.7-fold. By contrast, in the mature wood zone the tracheid lengths was stabilized at a certain level, showing slight fluctuations. The differences in the tracheids length of early and late wood in the examined annual rings were also determined, and it was established that for the majority of annual rings they are statistically significant (p<0.05).
Static bending tests to measure modulus of elasticity (MOE
ST
) 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 MOE
ST
tests; however, relationships between the different modes of measurement need to be established. Non-destructive testing MOE measured by two methods (SilviScan MOE
SS
and time of flight MOE
TOF
) have been compared with MOE
ST
for lodgepole pine and white spruce. The relationships between stress wave speed (SWS) and MOE
ST
have also been evaluated. Simple linear regressions of MOE
SS
, MOE
TOF
, and SWS had greater explanatory power (higher coefficients of determination (R
2
)) than did multiple linear regressions including growth rate or other wood fibre attributes. Simple linear regression from MOE
TOF
and MOE
SS
on MOE
ST
had lower R
2
for lodgepole pine than for white spruce; however, the converse was true for SWS. SWS had the highest R
2
(89%) and MOE
SS
the lowest R
2
(47%) when regressed on MOE
ST
in lodgepole pine. The results were tool and species specific, suggesting that R
2
between MOE
ST
and non-destructive testing MOE values must be validated separately for each commercial tree species and for each measurement technique.
We examined phenotypic relationships among radial growth-related, physical (i.e., related to wood density), and anatomical (i.e., related to tracheid dimensions) wood properties in white spruce ...(Picea glauca (Moench) Voss), in order to determine the strength and significance of their correlations. Additionally, principal component analysis (PCA) was used to establish if all of the properties must be measured and to determine the key properties that can be used as proxies for the other variables. Radial growth-related and physical properties were measured with an X-ray densitometer, while anatomical properties were measured with a Fiber Quality Analyzer. Fifteen wood properties (tracheid length (TL) and diameter (TD), earlywood tracheid length (ETL) and diameter (ETD), latewood tracheid length (LTL) and diameter (LTD), ring width (RW), ring area (RA), earlywood width (EWW), latewood width (LWW), latewood proportion (LWP), ring density (RD), intra-ring density variation, earlywood density (EWD), and latewood density (LWD)) were assessed. Relationships were evaluated at intra-ring and inter-ring levels in the juvenile wood (JW) and mature wood (MW) zones. Except for a few cases when mature tracheid diameter (TD) was involved, all intra-ring anatomical properties were highly and significantly correlated. Radial growth properties were correlated, with stronger relationships in MW compared to JW. Physical properties were often positively and significantly correlated in both JW and MW. A higher earlywood density coupled with a lower latewood density favored wood uniformity, i.e., the homogeneity of ring density within a growth ring. Managing plantations to suppress trees growth during JW formation, and enhancing radial growth when MW formation starts will favor overall wood quality. In order, RW-EWW-RA, TL-ETL-LTL, and RD-EWD-LWP are the three clusters that appeared in the three wood zones, the whole pith-to-bark radial section, the juvenile wood zone, and the mature wood zone.
Out-of-grade pine timber is an abundant material resource that is underutilised because its mechanical properties are not well understood. Increasing trends toward shorter rotation times and ...fast-grown plantation pines around the world such as Pinus elliottii × P. caribaea var. hondurensis hybrid (PEE × PCH) mean low-stiffness corewood is becoming a larger portion of this out-of-grade population. This study characterised the modulus and strength properties in bending, compression parallel to grain (CParG) and compression perpendicular to grain (CPerpG), shear and tension strength of low-stiffness out-of-grade PEE × PCH. The effect of resin, knots and pith on these properties were also investigated. The results show that in clear wood, the MOE in bending, CParG, CPerpG and shear modulus are 6.9 GPa, 5.78 GPa, 0.27 GPa and 0.59 GPa, respectively, while strengths are 45.8 MPa, 29.4 MPa, 6.7 MPa, 5.7 MPa, respectively. The tensile strength is 32.4 MPa. Resin significantly increased density 45% higher than clear, but performed similar with the exception of CPerpG MOE and strength which were significantly different. Resin area ratio (RAR) has a moderate correlation with density with an R2 of 0.659 but low to no correlation for mechanical properties. Knots were significantly different to clear for all test types and within a range of 48% to 196%. Knots were high in CPerpG MOE and strength but lower for all other properties and had the largest negative impact on tensile strength. Knot area ratio (KAR) had low to moderate correlation with tension strength and CPerpG MOE with R2 of 0.48 and 0.35, respectively. Pith was within the range of 76% to 121% of non-pith samples for structural performance, some of which were significantly different, and pith samples were higher in density than non-pith. This new information is crucial for the effective establishment of grading rules, design optimisation and utilisation of low-stiffness out-of-grade PEE × PCH as a new material resource in civil engineering applications.
This study investigates the effect of nitrogen fertilisation on the anatomical properties of the juvenile wood of the Populus alba L. clone ‘Villafranca’ from an experimental trial near the Drava ...River in Croatia. Nitrogen was applied for two consecutive years, and the immediate and potential post-treatment effects were investigated. The correlation between annual ring width (ARW) and individual wood anatomical properties was also examined. The fertilisation effect was confirmed after the first year of nitrogen application for all wood anatomical properties except the vessel lumen area (VLA). Fibre length (FL) was reduced, and double cell wall thickness (DCWT), ray area (RA), and cell wall area (CWA) increased. In contrast, the vessel lumen diameter (VLD) and vessel lumen area changed inconsistently between treatments. The second year of nitrogen application was determined to be effective for FL only. Due to the insignificant results in the second year of the application of nitrogen, the post-fertilisation effect of nitrogen fertilisation was not confirmed.
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