Knots are conspicuous flaws in the wood grain that appear as circular, darker regions compared to the surrounding wood. These knots form when a tree is cut vertically, and the knot appears as a circular patch of abnormal wood. This anomaly represents the former point where a branch was connected to the tree trunk, and as the tree continued to grow, the surrounding wood grew around it. Essentially, a visible knot denotes the location of a branch’s base.

Lower branches of a tree often die when they no longer receive adequate sunlight due to their location being shaded. Although these branches will not immediately detach, the tree will continue to grow around them, resulting in the characteristic conical shape of a knot. Dead buds or branches create dead spots in the wood that distort the contour of subsequent seasonal growth layers, producing knots. The wood in the knot has a firmer texture since its grain is perpendicular to the rest of the tree, and it has undergone compression.