What is a Knot
Knots are circular imperfections in wood that are typically darker than the surrounding material. Typically, knots result from a board being cut vertically from a tree trunk, exposing a base connection of a branch that the grain had grown around. The branches in question are typically those lower on the tree, which often die as it grows taller due to being gradually cut off from sunlight. The lower branches, however, are generally strong and healthy before this process occurs, and as such do not fall off immediately. Rather, what happens is that the tree grows around the base of the dying branch, which is what forms the knot. The grain of knots run perpendicular to the rest of the tree, which is what causes them to possess a harder texture than the rest of the board to which they belong.