The sapwood of a tree is the youngest wood in a tree’s trunk and is located in the outermost rings. All wood that exists in a tree either currently is or was once sapwood. This is because new wood is always sapwood until it reaches a certain age and level within the rings of the tree.
Most people are familiar with the fact that the age of a tree can be determined by the number of rings that are counted from the center of the trunk to the outermost edge. This, of course, is done after a tree is cut and a piece of its trunk is examined. At this time the sapwood can be identified.
Sapwood is identified in comparison with heartwood. Heartwood is the older wood that is deeper in the trunk of the tree and close to the center. This wood is sometimes darker in color and can be identified entirely based on its hue.
Sapwood is also called “living wood” because it is the wood that conducts water from the roots underground to the leaves in the branches. Not only does it conduct water throughout the tree, but it is also responsible for storing water and rationing out the stored water during dry spells.
Because this kind of younger wood performs such an important function, there is more sapwood required in larger trees. Also, trees that are growing very quickly require more sapwood than trees that have a slower rate of growth.
For building purposes, many woodworkers prefer to work with heartwood, as it is much stronger. Heartwood usually has a richer color and is more attractive. The younger wood can be useful for some building projects, but it is important to note that it will never be as strong as heartwood. Furthermore, because sapwood conducts water and heartwood does not, it has to be thoroughly dried before it can be used for anything.
Even after drying, sapwood is much more likely to warp than heartwood. For this reason, if it is used for a project, it must be used for something that can survive a bit of movement in the wood. Any piece of woodwork that is intended to last for a long time should be constructed of heartwood which is not only more beautiful in color, but also much more durable that the younger wood.