Noun
The hard, central part of the trunk of a tree, consisting of the old and matured wood, and usually differing in color from the outer layers. It is technically known as duramen, and distinguished from the softer sapwood or alburnum.
Source: Webster's dictionaryI think the tree is an element of regeneration which in itself is a concept of time. The oak is especially so because it is a slowly growing tree with a kind of really solid heartwood. It has always been a form of sculpture, a symbol for this planet. Joseph Beuys
Both come from the same species of tree (Caesalpinia echinata), but pernambuco, used for higher-quality bows, is the heartwood of the tree and is darker in color than brazilwood (which is sometimes stained to compensate). Source: Internet
It's summer at the Heartwood Hotel, and everyone is in a flurry getting ready for Ms. Prickles's wedding to Mr. Quillson Meanwhile, a new mouse guest named Strawberry comes to stay. Source: Internet
Consequently, the sapwood of an old tree, and particularly of a forest-grown tree, will be freer from knots than the inner heartwood. Source: Internet
Hence, a cross-section of a yew longbow shows the narrow, light-coloured sap-wood on the 'straight' part (riser) of the D, and the red/orange heartwood forms the curved part of the D, to balance the mechanical tension/compression stress. Source: Internet
In species which show a distinct difference between heartwood and sapwood the natural color of heartwood is usually darker than that of the sapwood, and very frequently the contrast is conspicuous (see section of yew log above). Source: Internet