1 They’re the core of your guitar sound.
It’s called “tonewood” for good reason. However much your pickups, amp, and effects influence your final tone, the cornerstone of a guitar’s voice is the wood it is constructed with. You can hear the difference in the resonance and response of different tonewoods even when a guitar is played unplugged. If desirable sonic elements aren’t happening in that acoustic sound, no amount of swapping and tweaking further down the signal chain will put them there when you go electric.
2 Sweet bodies.
A guitar’s body typically produces the most noticeable contribution of tonewood characteristics. The classic “Fender in the ’50s” wood— swamp ash—is, according to builder Dennis Fano, “very alive sounding, and it has a brighter tone than mahogany or alder, yet with good warmth and depth.” Alder, although not dramatically different sounding, tends to have a strong, clear, full-bodied, and well-balanced tone with sweet highs. Mahogany—arguably the most popular non-Fender wood—is somewhat rounder, warmer, and softer than ash or alder. Add a dense maple top (as on a Les Paul Standard), and you enhance clarity.
3 Neck woods get into the game.
The way a guitar’s neck vibrates also affects its tone. In the traditional Gibson configuration, a mahogany neck set into a mahogany body lends extra depth and richness for a thick, creamy tone. Use a maple neck instead—as Nik Huber does on his Krautster—and you hear more snap and definition. Marry an all-maple neck to the brightness of ash or alder, and you give birth to archetypal country twang or West Coast jangle.
4 The fretboard makes a difference, too.
“Adding a rosewood fretboard to an otherwise all-maple neck definitely rounds out the sound and warms it up to some degree,” says Chris Fleming, Fender Custom Shop Master Builder. “A maple neck and an ash or alder body has a brightness or edge to it that a rosewood guitar doesn’t.” A rosewood fretboard on a guitar made largely of mahogany might not be as noticeable, but add a dense, ebony fretboard in its place, and you’ll hear added clarity and high-end sizzle.
5 Construction matters.
However much players rave about the importance of tonewoods, the way they are actually put together in this thing we call “a guitar” makes a huge difference. (See “Five Things About Neck Joints” in the August 2011 GP for one such factor.) In addition, various stocks of the same wood can sound quite different. “So many other factors come into play to determine a guitar’s sound,” says Fleming. “For example—the density of the wood, the grain patterns in the wood, how old the wood is, and how dry it is.”