What characteristics set heartwood of certain species apart from nondurable wood?

Heartwood is the dense, inner part of a tree trunk that provides additional strength and stability. One of its key characteristics is its durability, particularly in comparison to nondurable wood. The heartwood of certain species is known to last significantly longer—often three to five times more than nondurable wood—because it contains natural preservatives and is denser. These properties make heartwood less susceptible to decay, insect damage, and environmental factors that typically degrade wood over time.

This durability is crucial for construction and outdoor applications, where longevity is important for structural integrity and reducing the need for frequent replacements or treatments. In contrast, nondurable wood lacks these inherent protective qualities, leading to a shorter lifespan and making it more vulnerable to wear and tear from environmental exposure.