What role does sapwood play in a tree, compared to heartwood?

Sapwood serves a vital function in a tree primarily related to the transportation of nutrients and water. This outer layer of the tree's wood is responsible for conducting sap, which contains essential nutrients and water absorbed from the soil. As part of the tree’s vascular system, sapwood actively supports the growth and sustenance of the tree by allowing these critical resources to move from the roots to the leaves and other parts of the tree.

In contrast to heartwood, which primarily functions as a support structure and can become denser over time, sapwood remains relatively softer and is essential for the tree's physiological processes. Heartwood, often the darker, central part of the tree, typically does not carry water or nutrients; instead, it provides stability and strength to the tree's overall structure.

The differences in their roles highlight why sapwood is crucial for the tree’s nutrition and growth, making the answer about its function in nutrient and water transportation the most accurate.