Axial variation of color and Shore D hardness in Cedrus libani wood

Abstract

This study examines the limited understanding of axial variation in color and hardness properties of Cedrus libani wood. In this context, the variation in color parameters and Shore D hardness across heart, heartwood, and sapwood sections was systematically investigated. Wood disc samples obtained from different axial positions of a 102-year-old tree were used to evaluate color properties, including lightness (L*), redness (a*), and yellowness (b*), together with hardness values. A total of 480 measurements were conducted across the three anatomical sections. The results demonstrated that both color and hardness properties vary systematically along the axial direction of the tree. Sapwood exhibited higher lightness values, whereas heart and heartwood showed comparatively lower L* values. Redness was more pronounced in heartwood and heart sections, while yellowness values were relatively similar across sections, with slightly higher values observed in the heart. In terms of mechanical properties, Shore D hardness increased from sapwood toward the center of the tree, reaching its maximum in the heart section. Additionally, axial differences were evident, with upper sections displaying higher hardness values compared to lower sections. These findings provide new insights into the axial variation of physical and mechanical properties in Cedrus libani wood, contributing to a better understanding of its material behavior. This knowledge is important for optimizing utilization strategies and improving performance-based classification of wood depending on its position within the tree.