Chewed tire surface

I appreciate the responses. Old Biscuit, it doesn't look like any of those wear chart picks. Mowdoc, I understand the difficulting in trying to picture it because it is difficult to describe. The trailer was just inspected which is required in NH and the tires passed. Also, I had the brakes checked and bearing greased so they had a good look at the wheels/tires. It happens on the front tire on each side and the second and third tires do not show the same damage. The best description I can give is that it looks to me like what might happen to the surface from backing up when the tire is not turning but really just being scraped on the pavement. It is only the first tire on each side, I see no other indication of wear or damage and I am meticulous about air pressure.