heartwood

(duramen) The central part of the secondary xylem in some woody plants containing nonfunctional tracheary elements, often blocked by *tyloses and infiltrated with organic compounds such as resins, tannins, gums, and many aromatic substances and pigments. The heartwood is derived from the *sapwood as it deteriorates due to age and damage. Heartwood is more highly prized than sapwood for the making of furniture, due to its greater density, darker colour, and greater resistance to decay.