A burl is a knot or wart-like growth on a tree in which the grain has grown in a deformed manner. It is typically seen as a rounded growth on the trunk and is caused by stress, either from an injury or by an infection with bacteria, virus or fungus. The largest recorded burl was found on a 525-year-old Sitka spruce in British Columbia. Its weight was estimated at 33 tons. Below is an Internet picture of it. It was found in a logging community, so the loggers cut it out and put it on display. If left attached to the tree, it likely would have grown larger.
Burl wood is sought after in woodworking because of its unique designs. However, the wood is hard to work with hand tools, because of the twisted grain. It has a tendency to chip and shatter. An Internet picture of a cut and polished burl can be seen below.
I have found one nice-sized burl on our property. It’s on the trunk of an American elm along the south fenceline. A picture of it is attached. Colorful lichens are on the bark. As the tree continues to grow, the burl will get bigger. I’ve seen several small burls at our place, but none the size of the one pictured.
