Problem definition and objectives: In countries like Iran, where forest resources are limited, the optimal use of native species to reduce pressure on forests and promote sustainable wood industries is of special importance. The wood of the Diospyros lotus species, which naturally grows in the northern forests of Iran, is considered one of the suitable options for this purpose. Examining the physical, biometric, and anatomical properties of this wood species can help identify its industrial and manual uses. Broadleaf trees generally exhibit variable characteristics that change depending on growth conditions, the growth region, and the position of the wood in the trunk. Changes in the biometric, physical, and anatomical characteristics of the wood can play a significant role in determining its suitability for use in wood and construction industries. Therefore, the aim of this research is to investigate the changes in the fundamental properties of Diospyros lotus wood along the longitudinal and radial axes of the trunk to assess its potential use in various industries.
Methodology: For this study, a healthy Diospyros lotus tree was selected from the forests of Behshahr (Mazandaran Province). Two 5 cm thick wood disks were taken from the tree at breast height and at a height of three meters. Test samples with dimensions of 2×2×3 cm was cut from the pith to the bark along the radial direction and at two different heights. The biometric properties, including fiber length, fiber diameter, cell cavity diameter, and cell wall thickness, were measured using a light microscope equipped with a calibrated lens. Physical properties, including dry density and critical density, were determined according to ISO 13061-2 standards. Additionally, the anatomical features of the wood were examined based on the microscopic features list of the International Association of Wood Anatomists (IAWA). The data obtained from the measurements were analyzed using one-way analysis of variance (ANOVA) in a completely randomized design, and mean comparisons were performed using Duncan’s test at the 95% and 99% confidence levels.
 
Results: The results showed that both the dry density and critical density of the wood increase from the pith to the bark, but decrease along the longitudinal axis from breast height toward the crown. A similar trend was observed for biometric properties, as fiber length, fiber diameter, cell cavity diameter, and cell wall thickness increased from the pith to the bark and decreased longitudinally from the base to the crown. These changes can be attributed to the increasing age of the cambial layer and structural changes in the wood cells during tree growth. Microscopic observations also revealed that the vessels are radially grouped, and alternating pits between the vessel walls were visible. Additionally, the wood rays of this species are heterogeneous to very heterogeneous, and the wood fibers have thick cell walls. These features play a key role in determining the strength and mechanical properties of the wood. The findings of this study indicated that as the distance from the pith increases, the fiber dimension increase, and the wood structure moves toward higher density and greater strength. On the other hand, the reduction in these properties longitudinally (from the base toward the crown of the tree) suggests structural differences in different parts of the trunk. These results align with previous research that reported similar changes in other species.
Conclusion: The results of this study demonstrated that Diospyros lotus wood, due to its high density, suitable cell wall thickness, and good strength, has excellent potential for use in the wood industries. The increase in biometric properties from the pith to the bark and the decrease from breast height to the crown reflect the impact of structural factors on the wood's properties. Furthermore, the microscopic anatomical results showed that Diospyros lotus wood has alternating pits between the vessels, radially grouped vessels, and heterogeneous wood rays, which can affect its mechanical behavior and industrial processing. The distribution pattern of the vessels and the arrangement of the wood rays suggest that this wood has the potential for producing high-strength compressed boards and wooden products. However, the impact of these features on wood processing and specific applications requires further investigation.