Modelling the variability of density and bending properties of Norway spruce structural timber

Fischer, Carolin; Vestøl, Geir I.; Høibø, Olav

doi:10.1139/cjfr-2016-0022

Cited by 10 publications

(5 citation statements)

References 32 publications

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“…In the N832 report, the f m,k values for each country ranged between 20 and 26 N/mm 2 (average 21.9 N/mm 2 ) for spruce, and 17-23 N/mm 2 (average 19.8 N/mm 2 ) for pine. It is common for spruce and pine from Scandinavia and Central Europe to achieve strength classes above C22 (Fischer et al 2016(Fischer et al , 2015Hanhijärvi and Ranta-Maunus 2008;Høibø et al 2013;Stöd et al 2016). In Ireland and the UK, the main species grown for construction is Sitka spruce (Picea sitchensis (Bong) Carr.).…”

Section: Introductionmentioning

confidence: 99%

The relationship between bending and tension strength of Irish and UK spruce and pine

et al. 2022

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The correct characterisation of wood properties is fundamental for the best utilisation of resources. In Europe, grading is defined by strength classes that are determined based on either bending or tension tests. The European standards give equations to estimate characteristic strength in tension from characteristic strength in bending, and vice versa depending on which was tested. These equations are applied to all softwoods. The aim of this paper is to empirically determine the relationship between bending and tension strength properties using two conifer species grown in Ireland and the UK. The results show that the relationships change with species. The standard conversion underestimates, importantly, the performance of spruce for tension loads calculated for the most common bending strength class for Ireland and the UK, C16. The opposite occurs on the reverse conversion. Additionally, the study includes published data from continental Europe, to establish a new conversion that uses timber from a broader range of grades, and that adjusts the tension performance of Irish and UK spruce obtained from bending strength classes, ensuring safe values for design.

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Section: Introductionmentioning

confidence: 99%

The relationship between bending and tension strength of Irish and UK spruce and pine

et al. 2022

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“…In recent years and across the entire forest chain, research projects have analyzed the influence of silvicultural treatment, forestry management strategies and site conditions on the physical and mechanical properties of timber. The studies focused mainly on some of the economically most important tree species: Sitka spruce (Brazier and Mobbs 1993;Moore et al 2009b, a;Simic et al 2018), radiata pine (Downes et al 2002;Lasserre et al 2009), Douglas fir (Barrett and Kellogg 1984;Krajnc et al 2019), Pinus patula , Norway spruce (Høibø et al 2014;Fischer et al 2015Fischer et al , 2016, Scots pine (Høibø and Vestøl 2010;Auty et al 2014), Japanese larch (Fujimoto and Koga 2009) or birch (Cameron et al 1995) among others. To make the most use of the forest resource available regarding yields and mechanical properties, information on wood characteristic variation and sources of variation is essential (Moore et al 2013), in particular how the wood properties vary on the different scales (stands, trees, boards).…”

Section: Introductionmentioning

confidence: 99%

“…As the entire grading process relies strongly on the standard, such knowledge on variation might support the standardization in timber industry, increase the reliability of the achieved mechanical properties and guarantee strength and stiffness. Datasets containing information on forest, tree, log, and board characteristics are required to quantify the variation in mechanical wood properties along the production chain (Moore et al 2013;Fischer et al 2016;Rais et al 2022). Some studies could break down the total variation in mechanical properties into different levels via variance component analysis (VCA), i.e., using random-effects models and the overall mean of the dependent variable as fixed effect to estimate the amount of the variance components' contribution to the total variability in the dependent variable (Schützenmeister and Piepho 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Some studies could break down the total variation in mechanical properties into different levels via variance component analysis (VCA), i.e., using random-effects models and the overall mean of the dependent variable as fixed effect to estimate the amount of the variance components' contribution to the total variability in the dependent variable (Schützenmeister and Piepho 2012). Moore et al (2013) for Sitka spruce and Fischer et al (2016) and Vestøl et al (2016) for Norway spruce were able to assign approximately 80% of the total variation in strength values to within-stand differences; less than 20% was attributed to between-stand differences. In other investigations, mixed models with fixed and random effects were used.…”

Section: Introductionmentioning

confidence: 99%

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Timber tensile strength in mixed stands of European beech (Fagus sylvatica L.)

Rais¹,

Kovryga²,

Pretzsch

et al. 2022

Wood Sci Technol

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The conversion to climate-stable, resilient and productive forests has resulted in an increasing share of mixed stands. Different growth conditions and silvicultural treatments lead to an increased scatter in strength compared to what is expected from monoculture experience. The study (i) quantified the magnitude of variation in strength of European beech timber from stands of different composition and (ii) showed the impact of grading on the characteristic strength value of timber coming from those stands. Strength grading models and machine settings for hardwood tensile classes on over 900 European beech (Fagus sylvatica L.) boards were derived. One model used only the dynamic modulus of elasticity (Edyn), and a more complex model used a knot value in addition. Afterwards, 407 boards from pure beech stands as well as mixed stands of beech with Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), Norway spruce (Picea abies (L.) Karst.), sessile oak (Quercus petraea (Matt.) Liebl.), and Scots pine (Pinus sylvestris L.) were graded and analyzed for their material properties from tension tests parallel to grain. Although a variance components analysis attributed only 4.2% of the variation to mixture, the ungraded timber showed significant strength differences between the pure and the beech-pine stands (65.2 versus 46.6 MPa). The yield of the material graded to the highest class in a class combination was higher in pure beech stands. The required characteristic strength values were mostly met for boards from the pure stands; while boards from the beech-pine mixed stands hardly ever reached the required values. To reduce strength variation and guarantee reliable timber products, strength grading should consider the various growth situations in forests when sampling material for the derivation of settings.

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“…The desired properties of wood depend largely on the end use requirements of wood. For example, a high wood density means commonly good mechanical wood properties (Fischer et al 2016). In addition, the higher the wood density, the higher the yield of wood compounds per volume unit of wood.…”

Section: Introductionmentioning

confidence: 99%

Relationships of wood anatomy with growth and wood density in three Norway spruce clones of Finnish origin

et al. 2017

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The relationships between anatomical characteristics of wood, growth, and wood density were studied in three Finnish Norway spruce clones, which had differences in average stem volume and wood density. This was done to determine which anatomical characteristics are affected by growth and which affect wood density, and to determine if clones of different geographical origins (Southeastern, C43; Southern, C308; Southwestern, C332) differ from each other in these respects. In this study, tracheid double wall thickness (2CWT), lumen diameter and wall:lumen ratio, numbers, sizes, and percentages of resin canals, and numbers of rays were correlated with ring, earlywood, and latewood widths and densities. The wood density correlated positively with the wall:lumen diameter ratio. Rapid growth decreased the number of rays independently of the clone. Furthermore, the effects of growth on the number and size of resin canals depended strongly on the clone. C332 had very thin tracheid walls in latewood, which decreased wood density. However, the high number of rays and resin canals increased it. Growth significantly influences wood anatomy and, consequently, wood density. Hence, wood anatomy should be considered in the selection of proper genotypes for forest cultivation in a changing, growing environment.

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Modelling the variability of density and bending properties of Norway spruce structural timber

Cited by 10 publications

References 32 publications

The relationship between bending and tension strength of Irish and UK spruce and pine

The relationship between bending and tension strength of Irish and UK spruce and pine

Timber tensile strength in mixed stands of European beech (Fagus sylvatica L.)

Relationships of wood anatomy with growth and wood density in three Norway spruce clones of Finnish origin

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