Coffee Burl
Burl Wood
Burl wood is a type of wood used by artists to create sculptures and other items, such as clocks and even some forms of furniture. Burl wood is highly prized by artists because of its unique shapes and ring patterns. Burl wood is a type of fast growing, abnormal growth found on some trees. Burl wood grows because the tree has experienced some sort of environmental stress or damage. This is often caused by either a fungal attack or an attack by insects.
The number of trees that produce burl wood is quite low. In addition, certain areas tend to create more burl wood than others, because all or many of the trees in a particular location are likely to be attacked by the same fungus or insects. Certain species also tend to be more susceptible to attacks and, therefore, more likely to develop burl wood. For this reason, certain types of burl wood are more rare and prized than others. Often, a tree that has developed burl wood is still quite healthy. In fact, many trees with burl wood can go on to live for many more years. Other trees develop burl wood offshoots that are so large and heavy that they create additional stress on the tree and can cause the tree to die.
When used in woodcrafting, burl wood is removed from the tree, preferably after the tree has already died in order to avoid killing the tree. It is then cut open in order to review the pattern inside. Sometimes, a single burl wood offshoot can produce several different pieces for an artist to work with.
Some burl wood offshoots develop regular growth rings that simply grow at an accelerated rate. This type of burl wood is not as sought after by artists as other forms of burl wood, because the patterns on this wood are not as interesting to look at. The majority of woodworking artists prefer burl wood that grows in irregular patterns that swirl and contain what are referred to as eyes – small spots that develop on the wood. While pieces with unusual patterns are the most desired form of burl wood, they are also the most difficult to work with. This is because the irregular patterns of burl wood make it harder to saw, chisel, and cut without splitting the wood or accidentally cutting it in the wrong direction.
Coffeewood
Other Common Names
ebano (Mexico), Granadillo (Colombia, Venezuela).
Distribution: Chiefly Venezuela but also found in Colombia, Ecuador, and Peru.
The Tree: Mature trees are from 50 to 75 ft tail, with a well-formed trunk sometimes 36 in. in diameter, clear of branches for 35 ft.
The Wood
General Characteristics: Heartwood dark red to chocolate brown or nearly black, usually with fine pencil-striping of parenchyma; sharply demarcated from the yellowish or pinkish white sapwood. Luster medium to low; texture medium to coarse; grain straight to very irregular; without distinctive odor or taste.
Weight: Basic specific gravity (ovendry weight/green volume) 1.05; air-dry density 78 pcf.
Mechanical Properties: A heavy strong timber, but no technical data available on mechanical properties.
Drying and Shrinkage: Requires care in seasoning, slow drying. With adequate precautions, results are satisfactory. No shrinkage data available. Kiln schedule T3-C2 is suggested for 4/4 stock and T3-C1 for 8/4.
Working Properties: Difficult to work, but finishes smoothly; works very well in turnery.
Durability: Highly resistant to attack by decay fungi.
Preservation: Not treatable.
Uses: Specialty turnery. in countries of origin used for heavy construction work.