scholarly journals From Visual Grading and Dynamic Modulus of European Beech (Fagus sylvatica) Logs to Tensile Strength of Boards

Forests ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 77
Author(s):  
Mitja Plos ◽  
Barbara Fortuna ◽  
Tamara Šuligoj ◽  
Goran Turk
Keyword(s):  
Fagus Sylvatica ◽  
Standard Procedure ◽  
Beech Wood ◽  
European Beech ◽  
Coefficient Of Determination ◽  
Special Focus ◽  
Stiffness Properties ◽  
Dry Conditions ◽  
Strength And Stiffness ◽  
Non Destructive

The aim of the present paper is to assess the non-destructive indicating properties of Slovenian beech (Fagus sylvatica) logs and correlate them with the mechanical properties of the final product, which is boards. Beech logs were visually graded according to the standard procedure and vibrational frequencies were measured. Logs were further on sawn into boards which were also non-destructively tested in wet and dry conditions. Finally, the boards were experimentally tested in tension. Special focus was directed towards visual parameters of the beech logs and their influence on the overall quality of the output material. The longitudinal natural frequencies of the logs were studied as potential indicating properties. The results showed that a majority of the visual log grading parameters do not result in good quality timber in terms of strength and stiffness properties, and only few are decisive for the final classification. The coefficient of determination of the static MOE vs. dynamic MOE of logs was r2=0.13, whereas vs. the MOE of wet boards was r2=0.49. Using a few visual characteristics in combination with dynamic measurements of logs and of wet boards could help to increase the yield of high quality beech wood.

scholarly journals Modifying elastic modulus of two-component polyurethane adhesive for structural hardwood bonding

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
S. Bockel ◽  
S. Harling ◽  
J. Konnerth ◽  
P. Niemz ◽  
G. Weiland ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Polymer Films ◽  
Modulus Of Elasticity ◽  
Beech Wood ◽  
European Beech ◽  
Lap Joints ◽  
Climate Conditions ◽  
Wetting Properties ◽  
Two Component ◽  
Dry Conditions

Abstract Subject to this study is the modification of an experimental two-component polyurethane (2C PUR) as an alternative adhesive for structural hardwood bonding. The 2C PUR has been adapted by calcium carbonate as filler to increase its modulus of elasticity with the aim of increasing the modulus analogue to the ones typically observed for classic amino- and phenol based adhesives. The 2C PUR system was compared with a commercial one-component polyurethane (1C PUR) and a phenol resorcinol formaldehyde (PRF) adhesive. The wetting properties of the adhesives were tested in terms of surface tension, polar and dispersive part and contact angle on European beech wood (Fagus sylvatica L.). In addition, adhesive polymer films of 2C PUR were tested for tensile strength and modulus of elasticity (E-Modulus) following ISO 527-1. The adhesives bond performance on beech wood was determined by lap-joints according to EN 302-1 in various climate conditions. The results show that 2C PUR has proper wettability properties on beech wood. Adding 60% wt filler to the polyol component increased the E-Modulus from 2.3 GPa (0%) to 4.4 GPa. The tensile strength of the modified 2C PUR polymer films was comparable with the industrial 1C PUR. Tensile shear strength and wood failure percentage of 2C PUR lap-joints were increased by adding filler and met requirements in dry and re-dried conditions according to EN 302-1. However, the addition of filler didn’t result in an improvement in wet conditions. The present study shows sufficient performance for bonding hardwood with 2C PUR in dry conditions, while the system still needs to be improvement regarding its performance in humid conditions.

scholarly journals GC-MS and SPME Techniques Highlighted Contrasting Chemical Behaviour in the Water Extractives of Modified Castanea sativa Mill. and Fagus sylvatica L. Wood

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 986
Author(s):  
Marisabel Mecca ◽  
Luigi Todaro ◽  
Valentina Lo Giudice ◽  
Teresa Lovaglio ◽  
Maurizio D’Auria
Keyword(s):  
Fagus Sylvatica ◽  
Solid Phase ◽  
Beech Wood ◽  
Castanea Sativa ◽  
European Beech ◽  
Industrial Applications ◽  
Biologically Active ◽  
Wood Material ◽  
Castanea Sativa Mill ◽  
Fagus Sylvatica L

The sweet chestnut (Castanea sativa Mill.) and European beech (Fagus sylvatica L.) are wood species largely present in the European forest area. The composition and relative variation of the secondary metabolites of chestnut and European beech wood under thermal effect is a little-explored area. The wood material was thermally modified at 170 °C for 3 h using a thermo-vacuum technology. Raw and modified wood extracts were obtained with aqueous extraction techniques in an autoclave, subsequently lyophilized, solubilized in ethyl acetate, and determined by Gas Chromatographic-Mass Spectrometric Analyses (GC-MS). In addition, the volatile compounds were determined by Solid-Phase Micro Extraction (SPME) analyses. As a general statement, the extraction in an autoclave produced a higher number of compounds in the modified chestnut and beech wood compared to unmodified wood material. Beech wood showed low degradation in the compounds after modification. Notably, squalene and ar-tumerone were the main bioactive compounds present in beech wood extractives. Chestnut, conversely, showed a greater degradation after thermo-modification. However, a reduction in chemical compounds in the modified samples was also observed. In this case, the main biologically active compounds detected only in the chestnut control samples were apocynin and ar-tumerone. The recovery of this residual wood material, before energy consumption, could provide a sustainable and environmentally friendly means of obtaining natural chemicals suitable for various industrial applications.

scholarly journals Strength and stiffness predictions with focus on different acoustic measurement methods

2020 ◽  
Vol 78 (5) ◽  
pp. 941-949
Author(s):  
A. Kovryga ◽  
J. O. Chuquin Gamarra ◽  
J. W. G. van de Kuilen
Keyword(s):  
Longitudinal Vibration ◽  
Measurement Techniques ◽  
European Beech ◽  
Solid Wood ◽  
Average Density ◽  
Coefficient Of Determination ◽  
Measurement Systems ◽  
Hardwood Species ◽  
The Us ◽  
Strength And Stiffness

Abstract Strength grading is an important step for the production of homogenous and high-quality solid wood material. In particular, for hardwoods, the use of non-visible characteristics is indispensable. Dynamic MOE (Edyn) is an important parameter widely used for grading of softwoods and applicable to hardwoods as well. There are two common ways to measure Edyn—ultrasound (US) wave propagation and longitudinal vibration (LV) method. Both methods are used in practice, however, due to the different inherent measurement techniques, the results differ. The current paper analyses the stiffness and strength coefficients of determination for several temperate European hardwood species and emphasizes the differences between the two measurement systems. The performance was analysed with regard to grading techniques, testing modes for the mechanical properties (tension and bending) and wood qualities. For more than 2861 pieces of European ash (Fraxinus excelsior), European beech (Fagus sylvatica), European oak (Quercus spp.) and maple (Acer spp.), the Edyn was measured using both techniques, and destructive tests (tension and edgewise bending) were applied. The results show that LV has higher coefficient of determination compared to the US Edyn. The coefficient of determination for both methods and tensile application can be increased by calculating Edyn with average density. Furthermore, the results support species-independent strength grading of hardwoods. Further research on the effect of different wood qualities and sawing patterns is required.

scholarly journals Genomic basis of drought resistance in Fagus sylvatica

2020 ◽  
Author(s):  
Markus Pfenninger ◽  
Friederike Reuss ◽  
Angelika Kiebler ◽  
Philipp Schönnenbeck ◽  
Cosima Caliendo ◽  
...  
Keyword(s):  
Climate Change ◽  
Fagus Sylvatica ◽  
Drought Resistance ◽  
Stop Codon ◽  
Global Climate ◽  
Beech Wood ◽  
European Beech ◽  
Multilocus Genotype ◽  
Linear Discriminant ◽  
Genomic Basis

AbstractIn the course of global climate change, central Europe is experiencing more frequent and prolonged periods of drought. These drought events have severe and detrimental impacts on the forest ecosystem. The drought years 2018 and 2019 affected European beeches (Fagus sylvatica L.) in noticeably different ways: even in the same local stand, badly drought damaged trees immediately neighboured apparently healthy trees. This led to the hypothesis that the genotype rather than the environment was responsible for this conspicuous pattern. We used this natural experiment to study the genomic basis of drought resistance in a Pool-GWAS approach. Contrasting the extreme phenotypes, we identified 106 significantly associated SNPs throughout the genome. The majority of affected genes was previously implicated in drought reaction in other plant species. Most observed non-synonymous changes led either to a substantial functional amino acid exchange or a stop-codon. A SNP-assay with 70 informative loci allowed the successful prediction of drought phenotype from the multilocus genotype in 98.6% in a validation sample of 92 trees with Linear Discriminant Analysis. Drought resistance in European beech appeared to be a moderately polygenic trait that should nevertheless respond well to natural selection, selective management, and breeding. The widespread distribution of drought resistance across natural beech populations represents an important argument for maintaining genetic diversity in dynamic forest ecosystems. The results from this study could therefore contribute to harness beech wood forests against ongoing climate change.

Über die mechanische Bedeutung der Holzstrahlen | The mechanical relevance of wood rays

2003 ◽  
Vol 154 (12) ◽  
pp. 498-503 ◽  
Author(s):  
Ingo Burgert
Keyword(s):  
Beech Wood ◽  
Tensile Tests ◽  
Deciduous Tree ◽  
Biological Design ◽  
Transverse Tensile ◽  
Radial Reinforcement ◽  
Radial Strength ◽  
Transverse Tensile Strength ◽  
Strength And Stiffness ◽  
Technical Solutions

Three investigations into the mechanical relevance of wood rays were combined for this article. The main objective was to show, that, apart from physiological functions, rays also significantly influence the radial strength and stiffness of wood. In the first approach twelve deciduous tree species with various proportions of fractions of rays were examined for their transverse tensile strength and stiffness. The second approach was based on the comparison of the radial mechanical properties of wood with a very high proportion of fraction of rays and beech wood with a normal volume. In these two investigations the mechanical relevance of rays could only be deduced indirectly. By isolating big rays of beech and carrying out tensile tests on the tissue, we found direct evidence for the mechanical relevance. The results are discussed with regard to their biomechanical relevance. The importance of a radial reinforcement for the wood is underlined. Moreover, the principle of multi-functionality in nature is emphasized in keeping with a possible transfer of biological design to technical solutions.

scholarly journals How Does Radial Growth of Water-Stressed Populations of European Beech (Fagus sylvatica L.) Trees Vary under Multiple Drought Events?

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Tamalika Chakraborty ◽  
Albert Reif ◽  
Andreas Matzarakis ◽  
Somidh Saha
Keyword(s):  
Soil Water ◽  
Fagus Sylvatica ◽  
Tree Growth ◽  
Radial Growth ◽  
Basal Area ◽  
European Beech ◽  
Canopy Openness ◽  
Fagus Sylvatica L ◽  
The Impact ◽  
Neighborhood Competition

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe.

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