Document Type : Research Paper

Author

Department of Wood and Paper Science and Technology, Cha.C, Islamic Azad University, Chalus, Iran

Abstract

Background and Objective: Physical, biometric, and mechanical properties of wood are important indicators for assessing the quality and potential industrial and ecological applications of different wood species. Juniperus excelsa, due to its slow growth and unique cellular structure, exhibits distinctive characteristics in terms of density and mechanical strength. However, limited information is available regarding the variation of these properties along radial and longitudinal axes of the tree stem. This study aimed to investigate and analyze the changes in physical, biometric, and mechanical properties of J. excelsa wood along radial and longitudinal axes, and to identify patterns of variation from pith to bark and from the base to the top of the stem.
Materials and Methods: Three healthy J. excelsa trees were selected in the Hezar Masjed Mountains (Darghaz, Iran), and three stem sections were collected from each tree at breast height (1.3 m), 3 and 6m height. From each stem section, three radial samples from pith to bark were prepared for measuring physical properties (air-dried density, basic density, and volumetric shrinkage), biometric properties (tracheid length, tracheid diameter, and cell wall thickness), and mechanical properties (bending strength and modulus of elasticity). Data were analyzed using two-way ANOVA to examine the effects of radial and longitudinal positions on wood properties.
Results: The mean air-dried density and basic density, and volumetric shrinkage were 0.442 and 0.413 g/cm³, and volumetric swelling was 10.80%, respectively. Tracheid length, tracheid diameter, and cell wall thickness were 1.572 mm, 31.41 µm, and 5.58 µm, respectively, while bending strength and modulus of elasticity were 41.66 MPa and 4.47 GPa. The study demonstrates that physical, biometric, and mechanical properties of J. excelsa wood are strongly influenced by the sampling position along radial and longitudinal axes, with identifiable patterns from pith to bark and from the base to the top of the tree.
Conclusion: These findings provide valuable information for industrial applications of J. excelsa wood and sustainable management of its forest resources.

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