And this is where the book ends, in his "heartwood".
Two species of iroko, Chlorophora excelsa and C. regia, cover the breadth of tropical Africa and produce durable heartwood used in joinery, boatbuilding and marine work, flooring, furniture, and veneer; it is often used as a substitute for oak and teak.
The oldest xylem layers (i.e., the oldest annual rings) are in the dead central core, or heartwood, of the woody stem, which can often be recognized by its darker coloration.
D. dendo, native to Angola, is a valuable timber tree with very black and hard heartwood known as black ebony, as billetwood, or as Gabon, Lagos, Calabar, or Niger ebony.
Yew wood is hard, fine-grained, and heavy, with white or creamy sapwood and amber to brown heartwood.
Some species are known to cause heartwood rot in trees.
The cells therefore contain more water and lack the deposits of darkly staining chemical substances commonly found in heartwood.
Sapwood is thus paler and softer than heartwood and can usually be distinguished in cross sections, as in tree stumps, although the proportions and distinctness of the two types are variable in different species.
