European beech log and lumber grading in wet and dry conditions using longitudinal vibration
-
Andreas Rais
,
Hans Pretzsch
Abstract
In Central Europe, European beech (Fagus sylvatica L.) is the most frequently occurring hardwood species. An efficient grading method has the potential to promote its utilisation as construction material. Wood density, eigenfrequency and length were measured in 99 European beech logs for calculating the dynamic modulus of elasticity (MOEdyn) obtained by longitudinal vibration (resonance). In addition, the log taper was measured. Of those logs, 867 boards were cut using a bandsaw. The MOEdyn in green condition was determined on 505 of the boards and the MOEdyn in dry conditions was determined on all of them. The r2 value between the MOEdyn of a log and the mean of MOEdyn of its boards was 0.72 in the wet condition. The MOEdyn,12% of boards significantly increased by 88 N mm−2 for each centimetre away from the pith. The negative effect of log taper on MOEdyn of boards was barely significant (P-value = 0.050). The MOEdyn,12% was highly dependent on the MOEdyn,wet (r2 = 0.83) and was 17% higher than the MOEdyn,wet. The mechanical properties of European beech timber exceed those of European softwood species. However, the relationships regarding MOEdyn between different grading levels in the processing chain appear to be similar to those of softwoods.
Acknowledgements
We would like to recognize the help of Sebastian Duschner, Thomas Hefter, Franziska Partenhauser, Frank Dauven and Manfred Parr for finding appropriate sample trees. Many thanks to the staff and student assistants of the TU Munich for their support, specifically Lorenz Maag, Jonas Schweiger, Orlando Gamarra, Daniel Dittrich, Charlotte Lennertz, Ian Burke, Martin Jacobs, Matthias Ulbricht, Andriy Kovryga and Heribert Bergmeier. We thank Martin Bacher from Microtec for his valuable recommendations and two anonymous reviewers whose comments helped improving the manuscript.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: We thank the German Federal Ministry of Food and Agriculture for support of the project “Einfluss der waldbaulichen Baumartenmischung auf die Schnittholzqualität der Rotbuche (Fagus sylvatica L.) und Optimierung einer maschinellen Rundholzsortierung” (“Impacts of forest management on sawn timber quality of European beech (Fagus sylvatica L.) and optimising automatic log grading”). Additional funding was received from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie (grant agreement no. 778322). The wood was kindly sponsored by Bayerische Staatsforsten and sawn at sawmill Försch/Bavaria.
Employment or leadership: None declared.
Honorarium: None declared.
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Articles in the same Issue
- Frontmatter
- Original articles
- Axial variation in the cambium anatomy of Schizolobium parahyba var. amazonicum
- Effect of growth stress and interlocked grain on splitting of seven different hybrid clones of Eucalyptus grandis×Eucalyptus urophylla wood
- Dynamic parallel-to-grain compressive properties of three softwoods under seismic strain rates: tests and constitutive modeling
- European beech log and lumber grading in wet and dry conditions using longitudinal vibration
- Influence of chemical pretreatments on plant fiber cell wall and their implications on the appearance of fiber dislocations
- Enhancing the thermal stability, water repellency, and flame retardancy of wood treated with succinic anhydride and melamine-urea-formaldehyde resins
- Improvement of interfacial interaction in impregnated wood via grafting methyl methacrylate onto wood cell walls
- A study on the GA-BP neural network model for surface roughness of basswood-veneered medium-density fiberboard
- Characterisation and valorisation of the bark of Myrcia eximia DC. trees from the Amazon rainforest as a source of phenolic compounds
