What is the primary function of sapwood in trees?

Sapwood, the outer layer of the wood in a tree, plays a crucial role in the transport of nutrients and water. This layer is responsible for channeling water and dissolved minerals from the roots to the leaves, where photosynthesis occurs. The vascular system within the sapwood, specifically the xylem vessels, facilitates this movement, allowing the tree to maintain its physiological functions and overall health.

Moreover, sapwood is typically active in growth as opposed to the inner heartwood, which consists of dead cells that provide structural support. While the other functions listed—supporting structural integrity, storing energy, and protecting the heartwood—are important aspects of a tree's overall biology, they do not represent the primary role of sapwood. The main focus of sapwood is its involvement in the transport process, which is essential for the tree's survival and vitality.