Although a humorous answer, this isn't a bad example. Even if you bang a big wooden box, play the strings of a cello, acoustic guitar, mallet the notes on a glockenspiel, they all have certain characteristics in common where you should be able to tell that said thing is made of wood. (Unless you're the amateur sound engineer I encountered who seemingly couldn't hear anything above about 1khz..) Therefore, it wouldn't be out of the realms of possibility to suggest they have a 'woody tone'. And all have a lot going on in the mid-range frequencies, over, say, hammering a lump of steel or slapping someone around the face with a kipper.
Yes, don't get pedantic, there's always the odd exception to the rule and as I said earlier, the rest of the signal chain can make a big difference too, but, isolating the instrument alone, those woody frequencies are in broadband mids. Another trick is to roll of the very low bass frequencies and have a gentle roll off in the treble. The Bergantino B|Amp has both low and high pass filters on it that are brilliant for carving the ends of the frequency spectrum. Brilliant!