Arvo Ylinen. (1942). The effect of the amount of the summer wood on the elastic and tensile properties of coniferous trees. Acta Forestalia Fennica vol. 50 no. 5 article id 7358. https://doi.org/10.14214/aff.7358

Keywords: coniferous trees; tensile properties; elasticity; summer wood; autumn wood; linear function

Abstract | View details | Full text in PDF | Author Info

The dependence of elastic and tensile properties of coniferous trees on the share of summer wood can be presented as linear functions, if the soft wood is considered as a statically indefinite structure. By eliminating the share of summer wood by a certain function presented in the article, the elastic and tensile properties are the linear functions of density.

The functions are proved right by conducting strength tests on pine. Practical implications of the derived functions in rating the quality of wood are also presented.

The PDF contains a summary in Finnish.

Ylinen, E-mail: ay@mm.unknown

Category : Research article

article id 9914, category Research article

Jun Tanabe, Futoshi Ishiguri, Akira Tamura, Yuya Takashima, Jyunichi Ohshima, Kazuya Iizuka, Shinso Yokota. (2018). Within-tree radial and among-family variations in wood density, microfibril angle, and mechanical properties in Picea glehnii. Silva Fennica vol. 52 no. 2 article id 9914. https://doi.org/10.14214/sf.9914

Keywords: modulus of elasticity; modulus of rupture; early selection; tree breeding for wood quality

Highlights: The modulus of elasticity was affected by both microfibril angle and wood density, whereas the modulus of rupture was mainly affected by wood density in Picea glehnii; A larger degree of among-family variation in wood properties was detected in juvenile wood than in mature wood, indicating that genetic improvements in the mechanical properties may be more effective for juvenile wood.

Abstract | Full text in HTML | Full text in PDF | Author Info

Genetic improvements in the mechanical properties of wood are important in forestry species used for lumber, such as Picea. The within-tree radial and among-family variations for the modulus of elasticity (MOE), modulus of rupture (MOR), and their related traits [i.e., microfibril angle (MFA) of the S₂ layer in latewood tracheid and air-dry density (AD)] were evaluated in nine open-pollinated families of Picea glehnii (F. Schmidt) Mast. The radial variation in MOR was mainly affected by AD, whereas MOE was affected by MFA and AD. Higher F-values obtained by analysis of variance and coefficient of variation were observed for all properties at the 6th–15th annual ring, except for AD at the 6th–10th annual ring. This result suggests that the contribution of genetic effect is larger in these highly variable regions. In addition, positive correlation coefficients were obtained between wood properties at the 6th–15th annual ring and mean values of these properties. Therefore, genetic improvements for MOE, MOR, and their related traits in P. glehnii is likely to be more effective in juvenile wood, specifically at the 6th–15th annual ring from the pith.

Tanabe, Faculty of Education, Chiba University, Chiba, 263-8522, Japan E-mail: tanabe_j@chiba-u.jp
Ishiguri, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan E-mail: ishiguri@cc.utsunomiya-u.ac.jp
Tamura, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan E-mail: akirat@affrc.go.jp
Takashima, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan E-mail: ytakashima@ffpri.affrc.go.jp
Ohshima, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan E-mail: joshima@cc.utsunomiya-u.ac.jp
Iizuka, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan E-mail: kiizuka@cc.utsunomiya-u.ac.jp
Yokota, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan E-mail: yokotas@cc.utsunomiya-u.ac.jp

article id 341, category Research article

Sanni Raiskila, Pekka Saranpää, Kurt Fagerstedt, Tapio Laakso, Mia Löija, Riitta Mahlberg, Leena Paajanen, Anne-Christine Ritschkoff. (2006). Growth rate and wood properties of Norway spruce cutting clones on different sites. Silva Fennica vol. 40 no. 2 article id 341. https://doi.org/10.14214/sf.341

Keywords: Norway spruce; density; growth rate; mechanical strength; modulus of elasticity; modulus of rupture

Abstract | View details | Full text in PDF | Author Info

The effect of growth rate on weight density and strength properties of three Norway spruce cutting clones growing on three different sites in different geographic locations was studied. The purpose was to follow variation in wood physical and mechanical properties and in quality between fast-growing clones grown in environments differing in nutritional and soil properties and climate within the boreal zone. The cloned trees had been selected on grounds of good growth, health and quality. The cuttings were collected from three-year-old seedlings and rooted. The rooted cuttings were planted in the 1970’s and they were on average 26 years old at a time of felling. The variation of weight density was studied within the annual ring and within the stem between the juvenile and mature wood from the pith to the bark with an X-ray densitometric method. The average annual ring width (and latewood proportion, %) varied between the clones from 2.92±1.36 mm (15.34%) to 3.30±1.25 mm (11.80%) and between the sites from 2.76±1.07 mm (14.71%) to 3.70±1.22 mm (13.29%). The mean weight density was 0.461±0.077 g cm–3 and latewood density 0.750±0.125 g cm–3 in this material. The mean modulus of elasticity was 9.88±1.43 GPa, modulus of rupture 67.51±11.50 MPa and weight density of the test samples (ρ12) 414±44 kg m–3 in mature wood. The parameters studied showed clearly that the environment had a large effect while the three clones differed from each other similarly in the different sites, e.g. the fastest growing clone was fastest on all sites.

Raiskila, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: sr@nn.fi
Saranpää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pekka.saranpaa@metla.fi
Fagerstedt, Department of Biological and Environmental Sciences, Plant Biology, P.O. Box 65, FI-00014 University of Helsinki, Finland E-mail: kf@nn.fi
Laakso, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: tl@nn.fi
Löija, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: lm@nn.fi
Mahlberg, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: rm@nn.fi
Paajanen, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: lp@nn.fi
Ritschkoff, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail: acr@nn.fi

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