Figuring Out Figure: Crotch
Crotch is a figure that develops when a tree knits a trunk to a branch or two branches together (image 1). It is often referred to as a plume or a feather (image 2). Almost all hardwood trees have crotches although not all crotches are created equal in splendor. Some species such as cherry tend to have ingrown bark inclusions and "nervous" pith cracks. This is often characteristic of trees with hard bark such as cherry, oak and hickory. In these species sometimes it is necessary to cut ten logs to get one series of high quality crotch sets. Other species such as walnut and mahogany have much friendlier natures and produce high quality crotch sets more frequently.
Once a crotch log is cut and good quality pieces have been produced then extreme care must be taken in the drying process. Crotch grain is very similar to end grain and dries at a different rate then the face of the rest of the board. Waxing the figure pattern on the face of the board helps as do slow kiln schedules but even then grain separations are not uncommon (image 3). Accomplished wood workers can correct these defects using combinations of wedges of wood, sawdust and glue. When done properly it is almost impossible to see the correction. Uses for crotch grain range from gun stocks to featured panels.
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.