Longitudinal variation in selected wood properties of oriental beech and caucasian fir

In this study, several wood properties were investigated along with the longitudinal direction for oriental beech and caucasian fir trees grown in Turkey. Wood density, compression strength parallel to grain, chemical characteristics (holocelluose, celluose, lignin), fiber dimensions (fiber length, fiber width, fiber lumen width, fiber cell wall thickness) were measured from the sapwood of the discs taken at the stem heights of 1.30, 6.30 and 12.30 meters. Both wood species showed clear trends in wood properties along longitudinal direction. For both wood species, the highest values in density, compression strength, volumetric shrinkage and swelling were at 1.30 m stem height, and the investigated paraeters decreased along with the stem height, while longitudinal shrinkage and swelling percentage increased. The highest cellulose content was found at 1.30 m stem height, and the highest lignin content was found at 12.30 m stem height for both wood species. The longest fibers and the thickest fiber walls were determined at 1.30 m stem height in both wood species. These results clearly indicated that stem height greatly affected the investigated wood properties for both wood species