I had never connected guitars, pianos, harps or violins with any particular tree or trees until I started on my book about Sitka spruce, a conifer tree which grows naturally for 3600 km along a narrow coastal corridor from California to Alaska.
Since the mid-nineteenth century, when it journeyed as seeds from North America to Britain, Sitka spruce has had a second home in Atlantic Europe: mainly Ireland, Britain, Norway, France and Iceland. It’s just as well that it suits its new homeland because its native forests have been dwindling from heavy use ever since World War 1 when it was used to construct war planes. Nowadays Sitka spruce is used for your toilet paper, newspaper, computer paper, kitchen units and roof spars. However, it has a very special use in crafting ‘Soundboards’ for stringed instruments.
A soundboard is a shaped piece of wood against which the strings resonate via a bridge to increase the volume; the clarity of sound and overtones produced vary according to the species of timber tree – and even where that tree grew.
If you own a modern guitar, its soundboard is probably made of spruce wood. Sitka spruce is currently the most sought-after timber for guitar and piano soundboards and so is used, for instance, in all North American Steinway pianos and quality guitars.
For soundboards, Sitka spruce has to grow so slowly that when it is felled you see very narrow growth rings. The coast of Alaska, with its cool, wet climate provides ideal conditions for growing soundboard Sitka spruce; 300 to 600 years old, 30 inches or more in diameter, with 20 to 25 rings per inch are best. Slow growth means stiff wood with clarity of sound.
Sitka spruce is the most abundant plantation tree in Scotland where grows so fast that it puts on 3 or 4 rings per inch, is harvested at 40 to 50 years old when less than a foot in diameter! The soft wood and small size unfortunately makes it unsuitable for soundboards – and nobody has waited 300 years!
Of course, other tree species produce good soundboards. Red-coloured Western red cedar is popular; Engelmann spruce and ‘Adirondack’ or Red spruce are highly prized but as there are few large-enough trees left in North American forests, are expensive. Lutz spruce (a hybrid between Sitka and White spruce) is an excellent wood for guitar soundboards, but is very rare. European luthiers choose mainly Common (Norway) spruce, which grows across eastern Europe and Siberia. Experiments with metal soundboards are underway so as to save ancient forests and trees, but timbers are preferred by most players for their feel, beauty and quality of sound.
There is more on trees and soundboards in my recent book on Sitka spruce which you can buy here. Or read a luthier’s experience at https://bourgeoisguitars.net/tonewoods-htm/