Thanks for the reply above.
What causes a burl you ask? A burl is wartlike, deformed,growth on a tree or it's roots.Usually caused by injury or infection.This infection or injury is usually just under the bark.A burl is composed of cells that are like cancer cells are in mammals.Even though a tree has burls on it, the tree itself can still grow normally. Another name for burl is, tumor. Most people are more familiar with the word tumor but not so familiar with the word burl. Of course the explanation for burl is much more complex than my feeble attempt to explain it but mine is factual.
Thanks again joasis, and check my gallery out if you have some time. Mitch