A Burl or sometimes called Bur or Burr is a tree growth in which the grain has grown in some deformed manner. These can be seen in most cases as forms of round outgrowth on tree trucks or branches. Burl occurs as a result of the tree undergoing some type of stress. The causes can include injury, virus, fungus or insect infestation. Burls yield a very peculiar and highly figured wood, prized for it’s beauty. It is highly sought after by sculptors and wood turners alike. Furniture makers will take very thin veneers, for high-end furniture, and automakers will use it for interior panels. Burl can be very hard to work with hand tools or even on a lathe because of the grain being twisted an interlocked, but the results when finished are unmatched in turned pieces, due to the wild grain.