We have a big chunk of a tree trunk that sits at the edge of our back garden. It's from a maple tree that our neighbours had cut down a couple of years ago. It's actually kind of cool looking with interesting bark but, just last week, I was working close to it and noticed these weird sort of growths on the vertical, cut, edge. Internet research has me tentatively identifying them as, Daldinia Concentrica. Not the most attractive fungus, IMO and it gets worse.