The Structure of softwoods

Abstract

The secondary xylem of the conifers is commonly called softwood. This term can at times be misleading, however, as many coniferous woods are physically quite hard while some angiosperm hardwoods are, in fact, quite soft (e.g. balsa). Softwoods are simpler and more homogeneous in structure than hardwoods. The greater bulk of the axial cell system is made up of tracheids which function both in water conduction and support (Figs. 53 and 54). Some softwoods also have axial parenchyma cells but these are never as abundant as in hardwoods. Fibres and vessel elements are absent. Resin excreting epithelial cells and strand tracheids are the only other axial elements present, and these occur in a few softwoods only. The ray system is built up mostly of thin walled parenchyma cells with ray tracheids and horizontal resin canals present in some woods.