ANOTHER WHAT IS!
What is a BURR or BURL.
A burr is a hemispherical shaped gnarled growth that can be seen in various sizes growing on the trunks of many trees. The grain to be found when burrs are cut into useable sized pieces is very Blistered, Speckled, has "Birds Eyes", and can be Twisted but is rarely if ever plain. Most burrs can be said to fall within two groups or types, FLOW THROUGH or BLISTER. Planks of burr timber over 25mm thick need to be dried slowly to prevent cracking. A HANDY TIP on drying is to use "sticks" of different thickness to control the drying time of planked timber. Thin sticks will allow less air to pass between the planks than thick sticks so the drying is done more slowly.
FLOW THROUGH burrs have a mildly undulating exterior bark covering and a wavy or twisty grain pattern. The grain of the tree flows into and back out of the burr to continue on up the tree. This type is commonly found on Peach and Plum trees.
BLISTER burrs have grain that flows into the burr but does not flow out again. This causes a very fast growing burr, sometimes larger than the trunk on which it is growing, and the bark covering has a very rough and contorted look. The grain pattern is blistered and mottled with many "birds eyes". This is the most valued type and is very often used to make extremely decorative veneers. This type is commonly found on Elm, Walnut and Beech trees. (Courtesy of Fred Harris S.A.W. newsletter)
