Effect of some topographical factors on the anatomical of the wood of Fraxinus ornus L. trees growing in Rawanduz District

The ash species Fraxinus ornus L. was chosen to study the effect of elevation, elevation above sea level, and slope on the anatomical characteristics of its wood. Three areas were selected in the Rewandiz District of Erbil Governorate, The area is located 10 km east of Bekhal Waterfall and 123 km from Erbil. The areas are located between latitude 36 36' 43' N and longitude 44 31' 29" E, and their elevations ranged between 685 and 1180 meters above sea level. The latitude, longitude, slope ratios, and locations from which samples were taken were recorded. The results of this study showed a significant environmental influence and variation among the studied trees in the anatomical characteristics of the wood. It was found that there was a variation in the average dimensions of the vessel elements in the three studied locations. It was also found that there were environmental influences on the dimensions of the fibers, according to the facades, elevations and slope. Among the important diagnostic results for diagnosing the wood of this species is recording the presence of septate fibers in this study. It was also found that the qualitative characteristics have great diagnostic importance, as the number of rows of interlaced pits in the samples varied from one row (Uniseriate) to two rows (Biseriate), while the perforated sheet was of the simple perforated pits type. As for the presence of helical thickenings, they were found clearly and noticeably in it.