Heartwood
The dense, mature inner wood of a tree that no longer conducts sap, typically darker in color and more resistant to decay than the surrounding sapwood.
In-Depth Explanation
Heartwood forms as the tree ages and the older, innermost growth rings cease active water transport. Chemical compounds called extractives accumulate in these cells, giving heartwood its characteristic darker color and natural resistance to fungi and insects. Species like black walnut, cedar, and white oak are prized for their distinctively colored and durable heartwood. In decay-resistant species, heartwood is preferred for outdoor applications where the wood will be exposed to moisture. The contrast between dark heartwood and lighter sapwood can be a desirable design feature in live-edge slabs and rustic furniture.
Usage Example
The heartwood of the black walnut was a rich chocolate brown, providing a striking contrast to the creamy sapwood on the live-edge slab.