What is a hardwood?
Hardwood comes from dicot angiosperm trees. The term may also be used for the trees from which the wood is derived; these are usually broad-leaved. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.
Hardwood contrasts with softwood (which is from Gymnosperm trees).
Hardwoods are not necessarily harder than softwoods. In both groups there is an enormous variation in actual wood hardness, with the range in density in hardwoods completely including that of softwoods; some hardwoods (e.g., balsa) are softer than most softwoods, while yew is an example of a hard softwood.
Hardwood should not be confused with the term “heartwood”, which can be from hardwood or softwood.
Hardwoods have a more complex structure than softwoods. The dominant feature separating “hardwoods” from softwoods is the presence of pores, or vessels. The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall, such as spiral thickenings.
As their name suggests, the wood from these trees is generally harder than that of softwoods. Hardwoods are produced by angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter,but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought.
Hardwood from deciduous species, such as oak, normally shows annual growth rings, but these may be absent in some tropical hardwoods.”