It sounds like you're quite an experimenter, which is good. It also means you'll understand why anyone trying to interpret your results would have to know a lot more about your methods.

k, i set up the wood in front of an amp, tuned my guitar perfectly, and played the note that corresponded with the frequency at 120bpm or two minutes, and then tested the compression strength with a g clamp, based in the same positions, five times per piece. the numbers given above are averages of this result

Josh, a few questions for you. The answers may help you come to a conclusion.

What did you expect to happen and why?

Why pick those frequencies? I understand that you have 82.4Hz and then 2nd and 4th harmonics, why not a 3rd harmonic? Where does 359.2Hz come from?

Did you measure and weigh each sample of wood before and after?

You give no indication of the strength of untreated wood and so it is not possible to determine the percentage change. Why did you not do this?

How loud was the sound?

Did you try several blocks at differrent distances from the amp?

If you subject a block to this for longer periods does it get weaker/stronger?

to avoid any issues to do with strength, i used the same piece, cut into 5 pieces, each then divided into 5 segments. the frequencies i used were because, in a nutshell, they represent the E notes on a standard tuned guitar, and since the rise in pitch to each note is exponential, it seemed that after a certain point determining an increase in pitch of say, 50Hz, it would become too time consuming.

the 359.2 is a mistake, thats meant to be a 659.2, sorry about that. it also seems that i forgot to mention the control was 95N required to break the surface. (this is the point at which i classified failure) wood was eleven millimeters thick, and the clamps surface area was pi^2. 

i kept the wood that i had ot used in a separate room, through two closed doors to avoid the pieces being exposed to the noise beforehand.

again, i seemed to have forgotten to mention that i used a G clamp to test the compression strength of the wood. i apologize for for not mentioning this beforehand. 

It sounds like you were pretty careful. I wonder if you expected any change in the strength of the wood? And if so, why?

Wood - being organic material - is pretty variable from section to section, even within the same tree. Any carpenter will tell you how powerfully a drying piece of wood can tear itself apart, for instance.

Sorry to be a bore, but it would be standard procedure to see if the results are repeatable - even when the outcome fitted with some hypothesis that you had formulated before starting. I'm probably not the only reader to be puzzled by the observations you've made.