Of the many species of wood, one would wonder how and why any particular species found its way to wood-bodied string musical instruments. Aside from very special considerations for various components of the instrument (such as the durability of rosewood or ebony for fretboards), there are a wide variety of choices that will work well. For example, cherry can become a nice mandolin or mandola backboard and can be tuned in a similar fashion to maple; it just doesn't have the beautiful appearance of curly-figured maple. A good piece of tight-grained old-growth Ponderosa pine makes a great soundboard; it is just harder to get consistent knot-free and pitch-free pieces that we find in the spruce families.

A friend of ours, Dennis Anderson, built a mandolin with Juniper (Juniperus californica) ribs and backboard, Engelmann spruce (Picea engelmannii) soundboard, and Dennis used Manzanita (Arctostaphylos spp.) for the fretboard, bridge, and peghead overlay. The mandolin looks pretty and sounds really fine. Here's a photo taken at the Good Old Fashioned Bluegrass Festival of Dennis at the mic, Ken on the bass, Chris Rogers (a Luthierie Camp graduate) on the guitar, and me on the banjo.

Mahogany and walnut are also good choices for backboards, and you may recall a mandolin I showed you several months back that Kali (marketing director for our Luthierie Camps and on-line sales) built using Claro walnut (Juglans hindsii - also known as Hinds walnut) - a species of walnut that grows in California. I now own this instrument, and it has become my favorite sidekick because of its warmth, richness, and powerful driving tone. Claro often boasts rich figure and color, and every piece is different.

So, it's really okay to step out of the norm and experiment.

Typically, we pick strong, light wood with tight straight grain for soundboards, and this leads us to the spruce family. Sitka spruce (Picea sitchensis) has the interesting trait of having the highest weight-to-strength ratio of commercially available woods. Red spruce (Picea rubens) - what some folks refer to as Adirondack Red spruce - is also very strong for its weight but is a bit lighter than Sitka. While you could use any of several hardwoods for backboards, the maple family is the most common of the hardwoods because of its figured grain, which occurs in three common images: curly, quilted, and bird's eye. We particularly like western big leaf maple (Acer macrophyllum) for backboards because it is less dense than sugar maple (Acer saccharum) and yields a warmer tone.

However, among all the species of wood we use in musical instrument construction, Honduras mahogany (Swietenia macrophylla) stands out because of its unique structure. While there are several species of mahogany, none have the physical characteristics of Honduras mahogany and these characteristics have made it the favorite choice of instrument manufacturers for the last century.

Honduras mahogany machines well and is very kind to tools. Cutters and bits used solely for mahogany go a long way before needing to be re-sharpened. While the wood is very strong, it is also reasonably soft so sawing, cutting, shaping, and drilling are comparatively simple tasks.

Honduras mahogany has considerably small pores (cells) and requires minimal filler before finishing, and it glues well. Lacquers and commercial finishes bond very well to mahogany (better than they do to ebony or rosewood, for example) and chipping and flaking are minimal.

But, most importantly, Honduras mahogany is incredibly stable; it does not warp or twist, rarely checks, and it maintains its shape - a trait that the industry refers to as "dimensional stability." The stability of Honduras mahogany comes from its unique growth. As a tree grows, a new layer of cells is added to the trunk each year. This layer of cells grows beneath a membrane under the bark is known as the cambium layer. As each layer of cells is added, it becomes what we know as an "annular ring" (some folks call them "annual rings"). So, each ring marks a year in the tree's life.

However, as each layer is added to a Honduras mahogany tree, its cells are aligned at an angle to the trunk, growing in one direction for about eight to ten years and then wandering back in the other direction for about eight to ten years. So, over an eight to ten year period, the grain of the wood is overlapped in what becomes a very strong interwoven structure that is much like the construction of a fiberglass boat hull. You can see the overlapping cell structure by holding a piece of finished Honduras mahogany and moving it in the light; the shimmering effect is the result of interwoven grain. And, this overlapping makes this wood incredibly strong and very dimensionally stable.

A few weeks ago, Ken was re-sawing some Honduras mahogany in preparation for making some headblocks. As he laid one board down, he noticed the very systematic grain dictated by its annular rings (shown in photo above). A count of the annular rings revealed a change in growth direction of the rings on this piece about every nine or ten years.