MAPLE BURL BLOCKS
A burl results from a tree undergoing some form of stress. It may be caused by an injury, virus or fungus.
Most burls grow beneath the ground, attached to the roots as a type of malignancy that is generally not discovered until the tree dies or falls over. Such burls sometimes appear as groups of bulbous protrusions connected by a system of rope-like roots.
Almost all burl wood is covered by bark, even if it is underground. Insect infestation and certain types of mold infestation are the most common causes of this condition.