Which describes the manner in which lumber shrinks when it dries?

When lumber dries, the manner in which it shrinks is primarily determined by the orientation of the wood fibers and the cellular structure within the wood. Generally, lumber tends to shrink more in width than in length. This phenomenon occurs because the width of the wood is composed of a larger number of smaller fibers which are more susceptible to changes in moisture content compared to the length, which is formed of longer fibers that are more stable.

As moisture evaporates, the wood fibers contract, causing the wood to lose width more significantly than length. This is an important consideration for builders and contractors, as it affects how lumber should be cut and used in construction to minimize warping or other structural issues that can arise from this differential shrinkage. Proper understanding of this behavior helps in ensuring that the final installation maintains its integrity and appearance over time.

In contrast, the other alternatives do not accurately portray the behavior of drying wood. The suggestion that wood shrinks more in length or equally in width and length does not align with the physical properties of lumber and how it reacts to drying. Additionally, the notion that lumber does not shrink at all contradicts the well-documented processes of wood drying and its dimensional changes.