Influence of felling season, drying method and within-tree location on the brinell hardness and equilibrium moisture content of wood from 27–35-year-old Betula pendula

Abstract

The Brinell hardness and equilibrium moisture content (EMC) were measured from thinning-aged silver birch wood. Wood material both from the trees harvested in the first commercial thinning and from trees remaining on site after the thinning was included. The average Brinell hardness was 19.40 MPa. It correlated significantly with the basic density of wood. With respect to the distance from the pith, the Brinell hardness of air-dried wood was higher than that of artificially dried wood. The average EMC of the conditioned (20°C, 65% relative humidity) wood was 12.0%. The EMC of the wood also varied, with the EMC being higher for air-dried wood than for kiln-dried wood. EMC was the highest at a distance of 30–40 mm from the pith, decreasing towards both pith and log surface. Seasonal variation in both the Brinell hardness and the EMC of the wood was found. It was presumed to be a consequence of season-dependent physiological changes in trees.

Keywords:

• Basic density
• Betula pendula
• Brinell hardness
• EMC
• equilibrium moisture content
• felling season
• silver birch
• wood drying

Acknowledgments

This work was funded by the Academy of Finland through The Finnish Forest Cluster Research Programme (Project 43098), the Employment and Economy Development Centre for South Savo through the project Utilization of small-sized birch for furniture industries (EU funding) and the Finnish Forest Research Institute. The authors wish to thank the field workers of the University of Joensuu and the Finnish Forest Research Institute for measuring the empirical materials, and Professor Erkki Verkasalo for fruitful comments on the manuscript.

Notes

Möttönen, V. ¹ , Heräjärvi, H. ² , Koivunen, H. ² and Lindblad, J. ² (¹Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland, and ²Joensuu Research Centre, Finnish Forest Research Institute, Joensuu, Finland). Influence of felling season, drying method and within-tree location on the Brinell hardness and equilibrium moisture content of wood from 27–35-year-old Betula pendula.

Additional information

Notes on contributors

Veikko Möttönen

Möttönen, V. 1 , Heräjärvi, H. 2 , Koivunen, H. 2 and Lindblad, J. 2 (1Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland, and 2Joensuu Research Centre, Finnish Forest Research Institute, Joensuu, Finland). Influence of felling season, drying method and within-tree location on the Brinell hardness and equilibrium moisture content of wood from 27–35-year-old Betula pendula.