ALTITUDINAL CHANGES IN THE WOOD ELEMENTS OF Pinus nigra IN TWO DIFFERENT ASPECTS OF MOUNTAIN ULUDAG, TURKEY

In this study. the anatomical characteristics of Pinus nigra JF Arnold (black pine) in Mountain Uludag were studied using the samples from six different elevation zones on both northern and southern aspects. On the wood sections, radial and tangential diameters of tracheids, their frequencies, wall thicknesses and lengths, ray numbers per mm, ray heights and widths were measured. It is obtained that the diameters and lengths of tracheid (tracheid wall thicknesses, number per mm) increased (decreased) along the mountain from lower to upper elevations, following by southern and northern aspects, respectively. Our results showed that the wood samples were classified into two main groups as lower (first group, 550-1150 m a.s.1) and upper (second group, 1350-1550 m a.s.1) elevations. Elevational differences were found as the decisive factor forming the main groups, while the subgroups were clustered by aspect in particular