Figuring Out Figure: Curl
One of the most common figure patterns is curl (curly koa image 1). It is also referred to as tiger stripe and ripple. Curl is compression grain perpendicularly crossing the face of a board producing alternate stripes of hard and soft board fiber. This phenomenon creates a chatoyantcy in the board varying in strength depending on the degree of compression leaving the viewer with the illusion of a three-dimensional surface.
The indication of the figure in a log can be apparent under the bark by the prevalence of waves or rolls on the log's skin (Image 2), but the absentness of these rolls does not necessarily preclude the figure being present.
Some species such as butternut and walnut logs hide their figure well. The figure will appear in flat sawn, rift sawn and quarter sawn lumber. Quarter sawn curly maple (Image 3) is also referred to as fiddle back maple (some people erroneously refer to heavy figured flat sawn curly maple as fiddle back, but violin makers only use quartered lumber for the back and sides).
Curly figure can be present in many species among them koa, all maples, walnut, ash, oaks and even ebony. The trees that are figured tend to be rare mutations as I have found woodlots with trees from the same seed stock, soil, water supply and sun exposure where one tree is curly and all of the rest are plain. Most trees have a little triggering at the base of the trunk which is referred to as stump curl, but this disappears within a few feet from the base. Many trees also have a little triggering under large branches but again this does go far.
The working properties of tiger grain are similar to most figure patterns, it takes sharp tools and a steady hand to achieve smooth surfaces from a complicated grain structure, but with patience and experience extraordinary results can be achieved (Image 4).
About the author:
Rick Hearne, owner of Hearne Hardwoods, Inc., in Oxford, Pennsylvania, has been in the specialty lumber business for more than 25 years. Hearne Hardwoods carries an inventory of 1 million board feet of lumber in 120 different species, including at least 100,000 board feet of variously figured maple.