Some subwoofers are designed to be placed close to the floor so that floor reflections can reinforce their volume. I suppose you could adjust the volume control to compensate.
A proper location for the subwoofer would minimize excitation of room resonances. Most installations achieve this through either a room resonance calculation or trial-and-error -- moving the subwoofer around the room and listening for resonance excitation. A location selected based on decor considerations would be appropriate only through coincidence.
The support structure may have a resonant frequency within the range of the subwoofer's operation. This could cause sound coloration, as well as potentially disastrous destabilization of the structure and/or its contents. To your point, most speaker stands are designed to have their characteristic resonances out of the speaker's normal operating range, or the stands are so overbuilt that they remain resistant to excitation by the speaker. Perhaps your cherry shelves are likewise sturdy.
I have subwoofers in enclosures in two of my setups. In one, the subwoofer is on the bottom of a very solid wooden cabinet, open in the front. Since the subwoofer has two sidefiring radiators, I need to leave a good amount of space on either side of it or I can hear some coloration. I haven't had a problem with vibrational stability for the cabinet or its contents. The other subwoofer is on a built-in bookshelf. On occasion, I can hear something rattling on one of the shelves. I have hunted down most of my rattles and padded them away. Needless to say, neither of these is really recommended in an audiophile context. I'm not proud.
My key goals are to be able to enjoy the low notes at volume and to blend the subwoofer range in with that of the other speakers. The latter is difficult to achieve, and the more constraints placed on the subwoofer, e.g., limitations on locational flexibility, the harder it is to attain. Good luck.
