I posted this a long time ago... long time... I don't remember when, actually. I'll add this to Ukulele Player Magazine on the new website.
What tone, over all, do I want? A rosewood back and sides will have better low and mid-range tone than a mahogany uke. Spruce will be brighter than mahogany and will not mellow as much as cedar with age. Cedar will sound bright at first and just continue to get more mellow and sweeter with age. Then there are the exotic woods, starting with koa, very punchy with clear tone. Mango is softer and sweet, but it doesn't carry as well as koa. Zebrawood, pretty new on the market is bright, but it is a thinner tone than any of the others mentioned thus far. Maple is bright and combined with a spruce top will be one of the loudest ukes you can ever find, yet played softly, it can be about as sweet and mellow as any instrument. Maple is usually laminated, so the solid spruce top is important.
The "sound" changes with the combinations of wood, the bracing, the body size and shape, and variables in construction. Many companies have different sounds on different instruments depending on the choice of woods used. So, here is a basic rundown...
bright sound.... maple back and sides, spruce top (very loud).
fairly bright sound, warms with age.... solid mahogany
warm sound, warms slightly with age, not as loud as koa.... mango
bright sound, can give a pronounced "bark" with warm tone, yet very loud.... solid koa
warm sound with a sweet tone that gets sweeter with age.... mahogany back with cedar top
bright, yet warm sound that will mellow with age, but remain loud.... mahogany with spruce top
warm sound, middle-volume, with smooth sweet tone.... koa back and sides with a cedar top
warm, rich sound with good midrange and lower registers... rosewood back and sides, cedar top
warm, rich sound with brighter highs and good volume.... rosewood back and sides with spruce top
less common woods...
myrtle... bright, mid-range tone with good balance
zebrawood... chipper, bright tone, average volume (add a spruce top for increased volume)
monkeypod... sounds similar to Koa, not as pretty, but nice straight grain
blackwood... nice grain, sounds a lot like koa, warms with age
walnut... bright, loud, not commonly used in ukes... used a lot in hammer dulcimers.
sycamore... bright, mid-volume, but soft
redwood... very soft, but warm tone
I hope this helps answer questions about tone.