Birdseye Maple is another title which does not, necessarily, denote a specific Acer species — although the bulk of what is sold is Sugar Maple (Acer saccharum) — but rather a unique figuring that occurs in maple as a result of numerous small- to medium-sized knots accumulating in the wood. It remains one of the most coveted and sought-after of all figured maple varieties.
Although it has never been scientifically proven, the prevailing school of thought is that the figuring is reportedly caused by unfavorable growing conditions. As the tree attempts to access more sunlight, buds begin to sprout in its trunk — to try and grow more branches, to access more light — but the tree lacks the requisite nutrients to support the growth and the new shoots are aborted, resulting in “birdseyes” (small knots) embedded in the tree’s wood.
There can be very large variances in birdseye size and content. Boards with larger concentrations of birdseyes are, obviously, more sought after and thus command greater prices than more sparsely decorated pieces. When sanded and finish-sanded, boards featuring somewhat larger birdseyes can have an almost 3D look — like brown bumps, sitting up on a light golden surface.
There have been tearout issues associated with birdseyes, as sometimes these tiny knots can wind up leaving tiny voids. There are also justified concerns that the tiny voids may occur sometime after the wood has been put into service. Because of this, some electric guitar luthiers shy away from using Birdseye Maple for fretboard wood, as slotting the frets can prove adventurous (if not downright painful:-)). Others, who do use it, will apply a finish coat of some type of protective lacquer over the fretboard when completing the neck.