Bending properties of Norway spruce timber. Comparison between fast- and slow-grown stands and influence of radial position of sawn timber

Kliger, I. Robert; Perstorper, Mikael; Johansson, G.

doi:10.1051/forest:19980306

Cited by 21 publications

(3 citation statements)

References 4 publications

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“…For planted Norway spruce trees, density was found to decrease across the first three to five annual rings, and then slightly increase further throughout the mature wood (Kuçera 1994). Kliger et al (1998) found the same pattern. The longitudinal variation in density shows divergent patterns.…”

Section: Introductionsupporting

confidence: 61%

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

2016

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Density, modulus of elasticity (MOE), and bending strength (MOR) are important properties of structural timber, and knowledge about the variability of these properties is important to make efficient use of the timber. To utilize such information in the production of structural timber, the information must be available before sawing. This study presents models describing the variability of density and bending properties of Norway spruce (Picea abies L. Karst) boards within individual trees, as well as among trees and stands, based on geographical data and forest inventory data including external tree measurements. The models were based on 1551 boards from 17 sites in Southern Norway, Eastern Norway, and Trøndelag. Important variables describing variation in density, MOE, and MOR between sites were site index and elevation. For density, latitude gave additional information. Age, diameter at breast height, and longitudinal position within the tree were the most important variables at the tree level. The models explained major parts of the site variance of all properties, and for MOR, they explained a substantial part of the variance due to trees. In addition to being used for predicting the properties of structural timber from current forest resources, the models also provide information that can be used to predict the effects of silviculture on timber properties in future forest stands.

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Section: Introductionsupporting

confidence: 61%

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

2016

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“…The similarity of the results of the static and dynamic modulus of elasticity (MOE) is the basis for successful use of these methods in practice. Some studies show a very close dependence (with the correlation coefficient of up to 0.96) of the static and dynamic MOE (Tanaka et al 1991;Perstorper 1994;Ilic and Ozarska 1996;Kliger et al 1998;Ilic 2001), although the values of the dynamic measurements themselves are often somewhat higher than in the case of static tests (Cho 2007;Hassan et al 2013).…”

Section: Introductionmentioning

confidence: 96%

Comparison of Non-Destructive Methods Based on Natural Frequency for Determining the Modulus of Elasticity of Cupressus lusitanica and Populus x canadensis

et al. 2016

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A non-destructive method for measurement of the modulus of elasticity (MOE) was compared with the static method on beams of Cupressus lusitanica and Populus x canadensis. The dynamic method is based on the principle of the resonance frequency, using longitudinal vibrations (Timber Grader MTG, accelerometer) and the static method for measurement of the flexural modulus of elasticity is according to EN 408 (2012). The differences between the ascertained dynamic and static MOE values were 1.1% to 2.4% for the Populus x canadensis sample and 12.7% to 15.5% for the Cupressus lusitanica sample. Furthermore, the correlation dependence of the applied methods was determined and the regression equations are shown. Experimental measurement showed the effect of the knot clusters, which appeared primarily in Cupressus lusitanica samples and considerably impacted the resultant values.

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“…1. In general, sawn timber from spruce has a modulus of elasticity of around 8 to 15 GPa, a dry density of roughly 300 to 500 kg/m 3 , and a bending strength of around 30 to 60 MPa (Kliger et al 1998;Johansson and Kliger 2002;Hanhijärvi and Ranta-Maunus 2008;Raftery and Harte 2013). For pine, the material properties are rather similar, with a modulus of elasticity of around 8 to 12 GPa, a dry density of about 300 to 500 kg/m 3 , and a bending strength of 30 to 45 MPa (Hanhijärvi and Ranta-Maunus 2008).…”

Section: Methodsmentioning

confidence: 99%

Using Small Diameter Logs for Cross-Laminated Timber Production

Fredriksson¹,

Bomark²,

Broman³

et al. 2015

BioResources

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Sawing small diameter logs results in lower yield compared to sawing large diameter logs. This is due to geometry; fitting rectangular blocks inside an approximately cylindrical shape is more difficult for small than for large diameters. If small diameter logs were sawn in a way that follows the outer shape, yield would increase. The present study considers whether this can be done by sawing flitches into trapeze shapes. These can be glued together into rectangular products. Cross laminated timber (CLT) products are suitable for this. The study was based on 4,860 softwood logs that where scanned, and the scanning data was used for sawing simulation. The log top diameters ranged from 92 to 434 mm. The volume yield of CLT production using trapeze edging was compared to cant sawing of boards. The trapeze edging and CLT production process improved yield compared to cant sawing by 17.4 percent units, for logs of a top diameter smaller than 185 mm. For all logs, the yield decreased using the trapeze edging method. To conclude, a trapeze edging method shows promise in terms of increasing volume yield for small diameter logs, if boards can be properly taken care of in a CLT production process.

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Bending properties of Norway spruce timber. Comparison between fast- and slow-grown stands and influence of radial position of sawn timber

Cited by 21 publications

References 4 publications

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

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

Comparison of Non-Destructive Methods Based on Natural Frequency for Determining the Modulus of Elasticity of Cupressus lusitanica and Populus x canadensis

Using Small Diameter Logs for Cross-Laminated Timber Production

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