In remedial wood protection, heartwood is generally considered to be:

Heartwood is generally recognized as less susceptible to decay than sapwood. This stems from the natural processes that occur within the tree as it ages. As trees mature, the inner wood, or heartwood, becomes denser and often accumulates various protective compounds, including natural toxins and resins that can deter decay-causing organisms like fungi and insects.

In contrast, sapwood, which is the younger, outermost wood layer, is actively involved in transporting nutrients and moisture within the tree. It is typically higher in water content and may be more vulnerable to decay processes due to its composition and biological activity.

The comparative resilience of heartwood to decay makes it a preferred material in construction and wood products, particularly in areas where wood is exposed to moisture and potential decay issues.