I know what spalting is. It's a few different kinds of fungus eating away at the wood. Personification is a different thing entirely, it is a process that occurs to wood in an anerobic enviroment like a it fell down in a bog. Without air to nourish most of the fungus and bacteria that normally break wood down, it petrifies, slowly turning itself into something of a fossil over the course of thousands of years.
As far as woods go, dogwood is listed as having no adverse health effects in terms of working with it. Probably a good sign it will make a good pipe. A good number of domestic woods are as nasty as some of the exotics, I like to look up the woods i'm working with on wood-database, they have a pretty good list of the commonly used woods and their effects on the body.
