sapwood

sapwood, relatively thin, youngest, outer part of the woody stem of a tree, the part that conducts water and dissolved materials. In the cross section of a tree, the sapwood is recognizable by its texture and color; it is softer and lighter than the inner heartwood. As the tree grows in diameter, the innermost layers of sapwood become heartwood, and new sapwood is produced on the outside of the woody column. See wood.

For the NATO reporting name for the R-7 Semyorka intercontinental ballistic missile, see SS-6 Sapwood.

Sapwood is the outer layer of wood in a tree, next to the bark. Sapwood will mature into heartwood as the tree grows. See also wood#Heartwood and sapwood. The newer layers are the sapwood, and will stay sapwood for a certain number of years until the tree expands and new sapwood grows over it.