"Although the weight of the wood isn't telling, the density is." If you have two identically milled guitar bodies, and one weighs more than the other, isn't the heavier one also the denser one? "A friend of mine once owned a pair of 1962 Fender Stratocasters. One had an alder body, the other had ash. In all other respects, such as hardware, neck and even strings, they were the same. They certainly sounded different and the tighter alder-bodied guitar sustained longer than the heavier ash guitar." Well, that's one guy's anecdote, but I'm not sure he knows what he's talking about. How does he know the necks were identical? Did he take them off and weigh them? Did both Strats have tremolos? A hard-tail setup sustains way better then those old Fender trems. If they did both have trems, did he weigh them? Fender outsourced all their metal casting and switched suppliers a lot. Were both nuts the same material and mass, filed the same way? Proper nut and saddle setup is one of the most crucial elements in getting the maximum sustain out of your guitar. And what about the pickups--in the early 60's, if I'm not mistaken, Fender still cranked them one at a time; there was a lot of variation one to the next--even in the manufacture and weight of the magnets. This seems like a more likely explanation than the mysterious properties of ash grown in a wet place vs. alder grown in a dry place.