Heartwood and sapwood features of Sorbus torminalis grown in Iranian forests
In the present study anatomical, histometrical, chemical and physical properties of the wood of 45-year old trees were determined. For this purpose, three trees were randomly cut at Sangdeh-Mazndaran located in the northern part of Iran. Disks and logs were removed at breast height to study the respective wood properties. Fiber length, fiber diameter, fiber lumen diameter, cell wall thickness as well as lignin and cellulose content of sapwood are superior to those of heartwood. Growth rings boundaries are fairly distinct and can be distinguished by only two to three compact fiber layers. The wood is diffuse-porous and vessels are small and predominately solitary, hardly visible to the naked eye on transverse sections. Most rays are 2-seriate interspersed with only few 3-seriate and uniseriate rays, and composed of procumbent body cells with occasional marginal rows of upright and/or square cells.