If it is a thin bark like on a fruit tree I leave it on.
If it is a thick bark like on oak, I take a hatchet and kock it off. Not sure if it makes a difference or not, just what my father did and his father did.
It also gives me something to do while I'm watching the thermometer and having a beer. Honey...I'm busy chipping this bark, I can't help pull weeds right now.