What is Burl, or Burr in wood?
It often forms on a tree as a type of nodule or lump and in that lump is an intricate growth system which results in a beautiful, attractive unique pattern when the wood is cut into planks, or sliced into a veneer. Mostly, the burls grow beneath the ground, but when they are above ground level, they are quite noticeable in the form lumpy protrusions on the trunk of the tree. Obtaining the burl wood is expensive because of it scarcity.
What causes this?
Well, no one can say for sure, but it is almost like a type of malignancy or disease that forms causing the tree to create this lump or effect. Sometimes insect infestation or mould infestation can also cause this. In a nutshell, the burl will result when the tree undergoes some kind of stress.
The results of this burl are visually very attractive and very unique and can sometimes give the wood a very wild, busy look. Some common species you may have heard of is, Walnut Burl, Bird's Eye Maple, Elm Burl, Oak Burl, Poplar Burl and there are many others.
Where is it used?
This busy, wild grain, makes the wood very dense, which also makes it much harder than the species that it originates from. This makes it very sought after for making bowls and in the past, it was used for mallets, mauls and chisel handles used for hammering. Today it is used for instruments,inlays in tables, door panels, wooden wall paneling, dash boards in up-market cars, boat building etc. The burl wood is difficult to work with, because of its intricate knurled grain that has no specific direction and when sliced into veneer, it can easily buckle and crack or split. Having said all this, the end result, when it has been used in guitar making, furniture, panelling,or other types of instruments, the result is truly stunning, with a beautiful depth and lustre, as well as being unique, something that only nature can provide.