Interesting thread, and very good comments. Does wood "change" based upon it's environment? Well, it depends on the kind of wood, but to some extent, yes, it does. In this context, vis a vis a shaft, it could, but it would be very slightly. Noticeable? Perhaps to the keenest of feel, sensitivity, etc. Even then, it might be over the long-term. However, what will happen, over time, is that the structural integrity of the wood will change. There's texture, strength, feel, vibration, and more, in the wood and it changes due to impact, use, time, environment, humidity, temperature, and again, more. There could be a diminishing of the structural integrity, and once could definitely feel that over time, or immediately if there was a change or break down in the structural integrity of the wood. No different than with the old-fashion tennis rackets, or wood hockey sticks.
In addition, machine made or hand made, each piece of wood is different, even if it comes from the same tree, cutting, section, etc. However, go from the highest of altitudes to the lowest, the most humid environment to the lowest, and so on -- the change initially will be unnoticeable to most. Over time, perhaps, but what is more likely being felt or noticed is that change to the structural integrity. Is that change due to environment? Yes, again, to some extent, but initially it's slight.
As far as the CF shafts -- I know nothing about them! LOL. I am actually wanting to read and learn about them. I hear about high deflection, low deflection, and I have no idea what that means either, LOL. But I am interested in learning about CF as an alternative. My knee jerk reaction is -- wood butt and CF shaft -- how does that work? But then again, like I said, I know nothing about it, LOL. I am thinking something like -- half the hockey stick is CF and half is wood? Hmmmmm. Confusing to me, LOL. Thanks again everyone!