Cluster knot

Multiple knots in close proximity to each other, also known as cluster knots, occur when several small branches emerge from the tree trunk in close proximity and become embedded in the growing wood. As the tree grows, the knots become more pronounced and can be visible on the surface of the lumber.

Cluster knots are more common in certain tree species, such as pine and spruce, and can affect the strength and appearance of the wood. The presence of cluster knots can weaken the wood and reduce its structural integrity, making it more prone to splitting or breaking. In addition, the knots can also affect the appearance of the wood, as they can create bumps or irregularities on the surface.

To minimize the impact of cluster knots, lumber producers may use grading standards to determine the quality of the wood and sort it accordingly. Higher quality grades will have fewer knots and other defects, while lower grades may have more knots and other imperfections.