White Oak with Burl
A burl is a tree growth where the grain grows in a deformed manner, leaving a round outgrowth filled with small knots. Burls result from trees that undergo a type of stress caused by an injury, a virus, or a fungus. Most burls grow underground attached to the roots, but some grow higher on the trunk of the tree. Burls are sought after for their highly figured wood, which is often used for inlay or furniture.