Spiral grain in Norway spruce: constant change in grain angle in Scandinavian sawlogs

Spiral grain in Norway spruce : constant change in grain angle in Scandinavian sawlogs

Gjerdrum, Peder (author): Norwegian Forest Research Institute, Norway,Department of Economy, Technology and Processing

Säll, Harald (author): Växjö universitet,Institutionen för industriella produktionssystem,School of industrial engeneering

(creator_code:org_t)

Oxford University Press, 2002
2002
English.
In: Forestry (London). - : Oxford University Press. - 0015-752X .- 1464-3626. ; 75:2, s. 163-170

Related links:: https://academic.oup...; show more...; https://urn.kb.se/re...; https://doi.org/10.1...; show less...

Abstract Subject headings

Any evident grain deviation will reduce strength and increase warp in sawn timber. To describe the magnitude and variance of grain angle in Norway spruce, specimens from 1046 Norwegian sawlogs and 380 logs from Sweden and Finland were examined. For individual specimens, grain angle outside the innermost zone closest to the pith might be expressed by a simple linear function of radial distance from the pith. The intercept and inclination of this function are close to bivariate normally distributed with mean values (SD) of 2.7° mm−1 (1.9) and −0.039° mm−1 (0.037), respectively. Inclination is less negative for wider annual rings (r = 0.3), and intercept and inclination are negatively correlated (r = −0.4). The constant rate of change indicates inherited property rather than influence of any dynamic, external stimulus. No predictor for grain angle pattern was found. The linear model leads to simplifications both when observing the grain angle in the forestry, and in calculations of strength properties and distortion in the timber industry.

About the subject

AGRICULTURAL SCIENCES: AGRICULTURAL SCI ...; and Agriculture Fore ...; and Forest Science

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