Where guitars are concerned, once you move over £100 or so, you'll start to see descriptions from the manufacturers of which woods were used in their construction. These will be between the Top, Back and Sides, Neck and Fretboard, often using different combinations between the different parts.
That's very good of them, but what does it mean to you?
Actually, it can mean quite a lot and different woods can make a big difference to the sound. They're generally split into their wood types .
Cheaper guitars and folk instruments will use laminates, which are essentially thin layers of wood or veneer pressed together to form the hard shell, or a basic fibreboard like MDF.
Spruces are often used in the sound boards of instruments from the lute, violin, mandolin, and guitar families. Spruce is particularly suited for this use because of its high stiffness-to-weight ratio. One of the most popular for Guitars is Sitka (or Alaskan) spruce (Picea sitchensis) Another popular variety is Adirondack (or Red) spruce—which was particularly popular in the 1930s-40s and sees a ready revival on the vintage market today. Red spruce is very stiff and imparts a very strong fundamental response making it ideal for heavy, bluegrass "flat-picking" and other energetic styles of playing and are popular on Banjos. Engelmann spruce (Picea engelmannii) and Picea abies (variously known as Norwegian, German, Alpine, Italian or European spruce) are particularly valued for finger-style and classical guitars for its quicker musical response and broader tonal profile.
Cedar has been increasingly used in the construction of classical guitars since the 1950s and also to a lesser degree the construction of steel strung acoustics. Cedar responds well to low input levels and string energy, making it ideal for nylon strung guitars as they're not as loud or tense as their steel strung counterparts.
Other softwoods, such as Redwood, also appear.
Variation you can find with different Tonewoods
Yew was once widely used, but is no longer available due to overharvesting. Maple is probably the most common tonewood in the construction of instruments of lute and violin family as well as featuring extensively on Guitar necks. Mahogany is extensively used in the tops of some guitars as well as the back, sides, and necks of instruments of the mandolin and guitar families. It is a very common neck material due to its stability and lighter weight. Mahogany may also be used for the solid bodies of electric guitars, such as the Gibson Les Paul. Mahogany is the most common tonewood used due to its availability and relative low cost. Rosewoods are often used in the back and/or sides of guitars and mandolins as well as guitar fretboards. The most sought-after variety, Brazilian Rosewood, Dalbergia nigra, has become scarce and expensive due to severe trade restrictions (embargo and CITES), rarity and demand. The most widely used rosewood used now is east Indian Rosewood, often paired with a spruce top for steel string guitars and with spruce or cedar for classical guitars. Koa is traditionally used for ukuleles. Koa is also used for steel string guitars mostly due to its beauty and compressed dynamic range. Ebony Is also often used in non-tonewood applications in many types of instruments for fingerboards, tailpieces, tuning pegs, tail-pieces and so forth due to its attractive appearance, hardness and wear resistance.
So where do they come from?
Most tonewoods come from sustainable sources through specialist dealers. Spruce, for example, is very common, but large pieces with even grain represent a small proportion of total supply and can be expensive. Some tonewoods are particularly difficult to obtain on the open market, due to demand exceding supply or the fact that the trees have not been sourced sustainably.
Bubinga Felling in Cameroon
Mass market instrument manufacturers have therefore began to use Asian and African woods such as Bubinga (Guibourtia species) as inexpensive alternatives to traditional tonewoods.
So which wood does what?