Evaluation of Stiffness and Strength of Scots Pine Wood Using Resonance Frequency and Ultrasonic Techniques

The availability of traditional wood species used for musical instrument manufacturing has decreased in recent years. To overcome this problem, there is a need for alternative woods with acoustical properties similar to those traditionally used. This study investigated the acoustical properties of neem wood (Azadirachta indica A. Juss.) from trees irrigated with treated wastewater as a substitute for traditional wood and to indicate its suitability for musical instrument manufacturing. The results revealed a strong linear relationship between the dynamic modulus of elasticity (Ed) and shear modulus (G). Moreover, density (ρ) was a good predictor for both Ed and G. The findings showed that this wood has potential use in backs and ribs of stringed musical instruments. Comparison with traditional European wood species used for this purpose showed that this wood can be a successful alternative. Increased demand for water and diminishing availability of water resources have led to the use of treated wastewater in irrigation. Thus, extension of the cultivation of several tree species with close properties to traditional tonewood species under wastewater irrigation can play an important role in the future of the musical instrument industry.

The utilization of branchwood as lignocellulosic raw material source for paper production may have the potential of solving the problem of the availability of raw material in the pulp and paper industry. This study therefore compared the chemical composition and fiber morphological indices (according to Franklin’s method) of stemwood and branchwood in Eucalyptus camaldulensis and Pinus halepensis trees grown in Egypt. The statistical analysis showed a significant effect of species, wood type (stem and branchwood), and their interaction on the measured chemical constituents and fiber morphological indices at 0.05 significance level. In both genera, the stemwood exhibited a higher percentage of cellulose and hemicellulose and was lower in lignin, total extractives, and ash than those measured in branchwood. Also in both genera, the stemwood was higher in fiber length, Runkel ratio, rigidity coefficient, Muhlsteph ratio, and Luce’s shape factor, and lower in basic density and flexibility coefficient than those in branchwood. Based on the chemical analysis and the fiber morphological indices, the stemwood and branchwood of both species were suitable for paper production with various qualities. Moreover, good correlations were found in both stem and branchwood between the basic density and the fiber wall thickness and fiber lumen diameter. ln contrast, there was an independent association between the stemwood basic density and the fiber length, and this relationship in branchwood was positive for both genera.

This study aimed to manufacture particleboards from Casuarina cunninghamiana (C), Eucalyptus camaldulensis (E), and Pinus halepensis (P) trees irrigated with treated wastewater and their mixtures (E-C, E-P, and C-P) with 50%:50% for each individual raw material. Two urea formaldehyde resin levels (9% and 13%) were used. Modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond strength (IB) as mechanical properties and physical properties (water absorption and thickness swelling) were determined. The C-P panels with 9% and 13% resin levels showed the best mechanical and water resistant performance. All the 13% panels satisfy the minimum requirement of the European standard for the MOE, MOR, and IB except for the MOE of (P) panels, which was very close to the recommended value. The mixtures improved the water absorption and thickness swelling compared with the other produced panels especially for the 13% resin content panels. The (E-C) with 9% resin content showed the lowest mechanical properties and water resistance values. The three furnish types and their mixtures showed its suitability for particleboard production using the board processing conditions specified in this study.

Basic knowledge of the within tree chemical components variation is essential which affects the wood end-use. Therefore, this study aimed to determine the chemical constituents (cellulose, hemicellulose, lignin, total extractive, ash contents, pH, and the solubility in hot water, cold water, and 1% NaOH) at five different levels (base, 25%, 50%,75%, and 100% of total merchantable stem height) of Albizia lebbeck trees grown in Egypt. The results showed that there was a significant effect of tree height levels on all the measured chemical constituents at 0.05 probability level. There was no specific pattern for the variation in cellulose, hemicellulose, and the solubility in 1% NaOH with the tree height levels. The cellulose and hemicellulose contents were markedly decreased at 100% of total tree height. The lignin content showed a significant gradual increase from the base up to the top of the stem. In contrast, the ash content, total extractives, and the hot and cold-water extractives showed a gradual decrease from the base to the top of the stem. Correlation analysis showed a good negative relationship between lignin and both cellulose and hemicellulose contents. Based on the results of this study, the differences in chemical composition with height along the stem must be taken into account when using the wood of these locally grown trees in various wood industries such as furniture, parquet, plywood, and paneling.