SeerObserver wrote:What is the basis of this prohibition, and what lies below the surface even further? For example, it is said certain meats are prohibited not just because of acquisition issues, but further because the body may emit smells that inspire vengeful behavior from predatory animals. So wood may be prohibited for sanitary reasons (just a guess), but is there something further as well?
When laying down the prohibition against wooden almsbowls the Buddha didn't give any reason, but issues of hygiene do seem a likely explanation.
Later, prohibitions were laid down against almsbowls made of gold, silver, mother-of-pearl, beryl, crystal, bronze, glass, tin, lead, and copper (as well as a requirement that bowls be made of either clay or iron). These were in response to householders complaining that the monks, in using such bowls, were acting like householders (a stock phrase in Vinaya origin stories).