Instrument top woods are made from light flexible woods with stiffness and resonance. Usually they are made from spruce, Sitka being the most common. However cedar, mahogany and even maple are sometimes used. Tone is not only affected by the species of wood but by where, when and how the wood was grown. For example wet weather will promote quicker growth resulting in softer, wider summer rings. Dry and cold will slow the growth, giving a stiffer flex to the top. The quarter-sawn wood used on spruce tops will show light and dark lines, the lighter being the more quickly growing softer summer growth and the darker being the harder winter growth when less moisture is present. Of course as in the rest of life, the builder seeks a balance in these wood qualities for most instruments. Tapping and flexing the top can give an experienced builder reams of information on how a particular top will sound when paired with a specific set of back and sides.
Here is a list of our pages describing the varying characteristics of the most commonly used top woods.