WOOD RESEARCH Volume 69, Number 4, 2024
DOAN VAN DUONG, MASUMI HASEGAWA, MANH TUONG VU, and VAN HUNG HOANG

RADIAL AND AMONGCLONAL VARIATIONS OF TRANSVERSE SHRINKAGE AND BASIC DENSITY IN 5-YEAR-OLDACACIA AURICULIFORMIS CLONES PLANTED IN VIETNAM

This study investigatedtransverse shrinkages and wood density for Acacia auriculiformis trees from six clones planted in north-central Vietnam. Radial and among-clonal variations of partial and total shrinkages in tangential (respective to Tn and T) and radial (respective to Rn and R) directions, partial and total coefficient of anisotropy (respective to Tn/Rn and T/R), and basic density (BD) were examined. There were significant differences among clones for Rn and R, but no significant differences were found among clones for Tn and T. The lowest average Rn and R were detected in clones Clt18 and Clt26, suggesting that these clones might be more appropriate for breeding programs focused on improving shrinkage traits for sawn timber production. BD is not a good indicator for predicting transverse shrinkages. In contrasts, stress wave velocity measured in standing trees has the potential to be used as a non-destructive method for predicting the transverse shrinkage of A. auriculiformis planted in Vietnam

WOOD RESEARCH Volume 68, Number 1, 2023
Dénes Horváth, Sándor Fehér, and Mátyás Báder

The potential of producing high added value structural timber from lamellae waste. Test results and analysis

The research was based on the analysis of the density, bending strength and modulus of elasticity of 100 oak lamellae generated as small-sized production waste. In this part of the study series, the test results were presented in detail and analysed, in particularly the density distribution. Correlations between some test results have been shown. The dynamic and static test results were also compared. Despite the poor quality lamellae, the average density of the sample set corresponds to literary values and the distribution of density is normal. Specimens with low density are unsuitable for further use. But the density alone cannot be used for classification. Between static and dynamic modulus of elasticity can be found a good relationship. The relationships between density and both static and dynamic modulus of elasticity of the specimens can be considered as good, too. The best correlation is in bending tests between the deflection of the specimens in the elastic range and the bending strength.