Figuring Out Figure: Burl
Burl figure is one of the rarest and most beautiful figure patterns. Burls are balloon shaped growths composed of swirls of grain laced with eyes. They are often sliced into veneer but can also be produced into solids. As with birds eye, burl figure shows up on flat sawn faces so the veneer is rotary sliced and lumber should not be quartered or the figure will be a pin instead of eye. Traditional uses for burl figure include car dash boards, furniture drawer fronts and tops, and gunstocks. Contemporary uses include table and counter tops, sculpture, and electric guitar tops such as this one created from Amboyna burl by Scott Gordon.
Burls are considered by many to be cancers but I believe they are more similar to benign tumors. They are definitely cell structures growing out of control but they do not seem to kill the tree. Many burls are found in the root structure but they also occur on the trunk and branches. The pins will sprout new branches when exposed to light.