[ the craft of the guitar maker ]


2. The Soundboard

FOR centuries the soundboards of all good stringed instruments, whether harpsichords, lutes, viols, pianos or guitars, have been made from one family of trees. Many attempts have been made to find other timbers that might improve the quality of sound, but with conspicuously little success. So, the work of nearly all luthiers to this day continues to be dominated by this single family of trees: they are the pines, or Pinaceae. They include firs (Abies), cedars, larches, spruces (Picea), pines (Pinus) and hemlocks, and can be recognised by their needle-like leaves, and woody cones made up of spirally arranged scales. Together, they number around 300 species.

Perhaps because much of the timber from these trees has a rather similar appearance and often similar properties too, the confusion between different species has always been considerable. If you discover that a Tudor instrument had a 'belly of firr', then you are, in fact, very little the wiser. Even today, if you go to your local timber yard, you may well find that a whole variety of softwoods are grouped rather unceremoniously under the common title of 'deal'. This attitude is further encouraged because the wood is plain, relatively plentiful, and therefore cheap. Being strong and stable, it makes an excellent building material. However, this hides the more remarkable nature of these trees, that makes them so interesting to instrument makers. For when it comes to that magical business of making sound, they have a life and personality of their own, prized above all other timbers, when shaped with care and love into soundboards for all our stringed instruments.

The pines were some of the earliest trees to appear in the course of the earth's evolution. They were ideally suited to the harsh climate of the planet's temperamental youth: they grew rather fast and very strong. They could withstand severe cold and forest fires. Evolving at about the same time as the earliest insects on Earth, they could not rely on insects to pollinate them. So every year, just like the other incredibly ancient plants, their spores blew in the wind. Then the seeds in their cones were catapulted out as far as possible from the parent tree. They were among the mightiest of nature's creations, and forests of conifers marched unhindered to and fro across the continents following the edge of the ice-caps which advanced and retreated through the successive ice ages. Some early designs work so well that there is little need to make later changes. And so it has been with the conifers. They can grow in almost any temperate climate and, without the interference of man, would cover much of the northern hemisphere.

The timber of these trees is also very characteristic. Because the tree structure is relatively simple, the grain grows straight and even, giving wood that is very strong, elastic and light. When it comes to supporting loads, the wood of some conifers has the greatest strength to weight ratio of any timber. For the same reason, the grain gives the appearance of very strongly contrasting stripes (the winter and spring growth) with very little cross-grain pattern such as can often be found in the more complex structure of many hardwoods. This stark beauty was fully exploited in the Scandinavian pine furniture so fashionable a few years ago.

On the basis of experience, luthiers have learnt that not all the conifers give the best results. So, from the wide choice of possible timbers, they select just a few species. The most common choices are one or two of the firs, one or two spruces and one or two pines. I have never seen any instrument with a soundboard of larch, hemlock, or true cedar. Then, from within these species, you must select individual trees that grow in just the right way: in the right climate and the right part of the forest. If you take a close look at any odd pieces of softwood that you can find, you will find that they usually grow quite fast and may have typically about 5-10 growth rings to the inch. Many historic lutes show soundboards with up to about 40 rings to the inch! This sort of timber comes from a much slower-growing tree, found near the snowline on a mountainside. The colder climate means that the spring growth is much less in proportion to the dark autumn ring, so the grain lines are much closer together. This gives a tougher, denser piece of wood ideal for soundboards. The trees felled for soundboards are typically between 200 and 300 years old!

In recent years, one or two new woods have joined the traditional choices of instrument makers. The most important is Sitka spruce, which is perhaps no great surprise, since other kinds of spruce have been used for centuries. Most of this wood comes from Canada, and has proved to be nearly as versatile as its European cousins, finding favour with makers of guitars, lutes, and harpsichords among others. The other newcomer is western red cedar, used by many guitar makers in recent years, with very good results.

This is not, in fact, a cedar at all. It is 'red' because it is one of the family of North American redwoods, and 'western' because it grows along the west coast. Heavy commercial logging of the redwoods began in the 1850s as a result of the west coast population explosion. Over 90 per cent of the redwood forests have been destroyed in just over 100 years. Included among the redwoods are the sequoias, some of the most remarkable trees on Earth. Sequoias are the tallest of all living things, as well as some of the most ancient: a number of them are estimated to be over 3000 years old.

Western red cedar is rather more modest in size, but still grows massive and straight. The light, strong and rotresistant timber was preferred by the North American Indians for carving into totem poles. We in Europe find it particularly suitable for garden fencing.

In this environmentally aware decade, it may be well to spare a thought for the pine forests of Europe. Latest estimates suggest that 80 per cent of these trees will die by the end of the century. Many of the trees in the Alps and Scandinavia are already dying. It is almost certain that some form of pollution is to blame but, as yet, the exact cause is uncertain.

Isn't it time mankind began to value the planet's forests?

©1990 Trevor Semple

"Classical Guitar Magazine", September 1990

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