Does anyone use wood for vibration control?

For audio cones there is a direct relationship between performance and hardness. Check it out. The Moh’s scale of hardness has diamond as a perfect 10.0 The best sounding audio cones are high on the Moh scale, less sonically effective cones are lower on the Moh scale. The NASA grade ceramics DH (diamond hardness) cones are right below diamond on the Moh scale. The Shun Mook Diamond Resonators use diamond tips on highly resonant Mpingo wood. Then we have hardened high carbon steel, with aluminum, carbon fiber and brass much farther on down the scale. Followed by soft rubber type materials, which by and large tend to store energy as opposed to allow energy to exist the system rapidly. 

https://www.alansfactoryoutlet.com/hubfs/hardness-of-metals-visual-representation-mohs-scale-5.png

I built a custom rack with wood shelves using a vintage, heavy and stable welded iron frame I found at auction. The supporting brackets are simple 90 degree L bars welded to corner verticals. I needed to isolate all three shelves from direct contact with the iron frame which had a small but perceptible harmonic when hit.

The shelves are a layered concept consisting of a bottom layer of 3/4 inch Baltic plywood with an upper layer of 1 inch (finished thickness) tiger maple. The edges of the plywood cannot be seen as it is recessed into the L bars.

The two layers are isolated from the frame and from each other with Fat Dots from Herbie's Audio Lab. The decoupling is near perfect and there is little to no transmission of vibration to the maple. By using this "sandwich" design with two discrete layers of isolating/decoupling material I seem to have  eliminated the need for using 2+ inch wood stock.

Other than having to cover most of what is great looking tiger maple with equipment, I am super pleased with the results. The experiment paid off well.

The oft mentioned analogy between an audio system and a musical instrument is completely wrong. A logical fallacy. The real analogy is between audio systems and electron microscopes. The audio system needs to be isolated from building structure vibrations for the same reason electron microscopes require vibration isolation in order to take photos of the specimen under the scope without the picture coming out all blurry. Unless you like your music blurry, gentle readers, better head on down to your local isolation store. The only good vibration is a dead vibration. RIP. And, no, speakers are not like guitars. Cabinets resonances are completely unwelcome in a high end system. Nor are the mechanical feedback from speakers welcome, either. I’m pretty sure we’ve known that since the 70s. Hel-loo! Wake up and smell the coffee, guys! ☕️ Go, ahead, give me your best shot. 

Isolating components from vibrations is an audio fetish IMHO that is exploited by charlatans marketing to the worst of the nervosa syndrome.

Each object has a resonant frequency, and it's going to resonate in the presence of that frequency, and there's nothing you can do about it. You can change the resonant frequency, such as by putting sand or lead shot in a speaker stand, putting a bag of sand on top of a component, etc.

Buildings vibrate at frequencies that are inaudible. Carnegie Hall vibrates, but it affects neither the performance nor recording of the performance.