Alam Shah, forgive me, but jati gembol, or burl teak is formed the same as any other burl in wood.
It is a growth that is caused by the cells in the wood dividing and growing too much, a bit like cancer in a human being.
The things that can cause this are a branch that did not grow properly, or an infection, or an injury.
If you take material from around the roots, you can sometimes get a burl-like effect, and sometimes also find material with high chatoyancy, but the material from the butt of a tree is not burl.For instance, with akasia, the wood from around the root is usually the most highly chatoyant, but it is not burl.
Any burl can be beautiful, but probably the pick of all burl timber is thuya burl which comes from north Africa and Morocco.
The major problem with jati gembol as a wrongko wood is that it is very inclined to move---it is very unstable. You can make , say, a sandang walikat terusan from it in the wet season, and come dry season you may not be able to get the blade into it. Similar things can happen when you bring a wrongko from jati gembol to Australia, and then send it to, say, Arizona. In a super dry climate those beautiful grains can open right up. Curing is not the answer, and it does not happen with all pieces of this material, but it does happen often enough to cause some problems.
|