How Burls are Harvested and Sold
Burl wood is bought and sold by weight, so trying and figure the board foot on a burl block is useless. The weight is based on their original green weight with the bark still on. Burls are then waterblasted to remove bark. This can remove a significant amount of weight in itself. By the time the burls reach us, they may have lost 20% or more of their original harvest weight. This holds true with North American burls as well. Some burls, even within the same species have a thicker, more resinous bark, so that two specimens of the same harvest weight could differ markedly in weight after debarking. Burl shape also affects the bark to weight ratio. Some burls have more sapwood (which contains more moisture) on the edge and can lose more weight when drying. The original harvest weight of the burl is used throughout the sale process eliminating all these variables.
All burls should be considered green or partially air dried unless stated otherwise. Burlwood coming from Australia, as a requirement of our import permit, have been fumigated with methyl bromide. Most cut burl blocks are sealed with wax or anchor seal. It is the wholesaler's preference to seal or not to seal burl caps. Australian burl caps are typically not sealed whereas Tasmanian burls and blocks are.
Australian Burl Harvest
Not for the weak at heart!