Comparative wood anatomy of branch and trunk wood of some Turkish woody species

The anatomical, physical and mechanical differences between stem and branch wood in forest trees have been known for many years. Anatomical studies in Turkey have mainly focused on stem wood with little attention on branch woods. However, stem and branch woods differ significantly for vessel or tracheid frequency, vessel or tracheid tangential and radial diameter, ray frequency, ray width and ray height etc. In this study, stem and branch woods of Pinus brutia Ten., Alnus glutinosa (L.) Gaertn., Juglans regia L. and Robinia pseudoacacia L. species were compared for some of the properties. For P. brutia, the tangential and radial tracheid diameters are narrower and the number of tracheids per mm2 is higher in the branch wood compared to the stem wood. Similarly, the tangential and radial diameters of vessels are narrower and vessel frequencies are higher in the branch woods compared to the stem woods for A. glutinosa, J. regia and R. pseudoacacia. Ray widths of P. brutia, J. regia and R. pseudoacacia are narrower in branches than in stems. But for A. glutinosa ray width is narrower in stem wood. In branch woods of P. brutia and R. pseudoacacia, ray frequency is higher than in stem wood. In the other two species, there is no statistically significant difference between branch and stem wood in terms of ray frequency. In all species examined, ray height is shorter in branch wood, with some exceptional example trees.