If burls are formed, then something went wrong during the growth of the tree. Friends of the noble woods are particularly pleased, beacause the wild intricate fiber makes an appealing grain.
The formation of burls is actually an abnormality that results from sleeping buds. Every tree must constantly form buds from which new branches can grow – that is essential for them. Sometimes this mechanism is disturbed and the tree forms a lot of buds, but they don´t cast out. These dormant buds are overgrown by the surrounding wood and cause the tree to form burls. Often this process happens after an injury of the log.
Burls grew only on the log and above the ground, they can not be confused with root wood – wood that is obtained from roots can have a similar lively figured texture like burls, but it lacks the eyes as typical feature of veined wood. Furthermore, root wood is not suitable for processing into veneer – their wood is used, for example, for producing rifle shafts an grips of knifes.
Typical veined woods are:
Softwood: Vavone burl, Thuja burl
Hardwood: Maple burl, Amboyna burl, Birch burl, Madrone burl, Myrtle burl, Walnut burl, Poplar burl and the Elm burl.
The veined wood from the american walnut comes almost exclusively from plantations on the west coast of America – which serve to produce walnuts. From the moment of improvement, the american walnut deforms and enlarges and causes the formation of the burl. Another burl which also grows on plantations is the birch burl, which can be found in Finland.
The formation of veined wood is a special feature, this also explains the high price that achive such woods. But that is not the only reason. A problem of burls are enclaves of stones, metal parts, ingrown bark, shakes, hollow and rotten areas. It takes a lot of experience to cut a burl so that as much material as possible is produced.