I had intended this comment for the “tone rite” thread, but it closed before I had completed the post. Even so, I would still like to share my comments on wood anatomy for those interested. (especially since I took the effort to write it, instead of playing my mandolin!)
As a botanist, I spent some time in school learning and thinking about the structure of wood. Still do occasionally when I gaze at a tree or an interesting piece of wood. In a tree, wood (called xylem by us botanists) is composed of a mix of cell types; those closest to the bark function to transport water and minerals from roots to leaves. This sapwood contains a few living cells, some fibers, but is mostly dead, tube-like cells of various dimensions, connected into “water pipes”; the bigger water pipe cells are easy to see in a piece of oak cut perpendicular to the trunk. In heartwood, all the cells are dead and hold waste products deposited while living cells were still present. Remember that plants, just like you, need to eliminate waste products; they do this by depositing their “shit” (sorry for the technical term) into older wood cells. Depending on the species of tree, you get heartwood of different colors and chemical make-up. Plants are diverse chemical factories and this is why we get wood with an amazing range of tonal properties.
Given this architecture and mix of chemistry (very, very simplified above), it is not surprising that wood properties can change as it ages or as wood is subjected to external forces. That being said, I would need a lot more statistically valid data before I would spring for one of the discussed tone-altering machines. If I was doing the research (which I’m not), I would subject pieces of wood to the machine and compare wood anatomy and chemistry before and after. For a lasting effect on tone, I would expect to see some demonstrable alteration in cell architecture and/or chemistry. For those interested, there has been a lot of wood anatomy research as part of understanding Stradivarius instruments. Wood is pretty cool. A recent study estimated that there are about 73,000 different species of trees. Given that we currently use only a small handful to build musical instruments, I expect some fun discoveries in the future.