That tree doesn't look happy at all. Either it is bacterial canker or a rabbit or some such animal ate away part of the trunk. There isn't much you can do about such damage other than hope it recovers. Peaches often recover from canker unlike cherries which often do not recover.

Scott

You need to put copper fruit tree spray on it. You can mix a small batch a little strong and just paint it on. I did that to one of my trees that got a canker. To be honest If it were me I would replace it. Peach trees need to be sprayed with copper to prevent canker even if it was a rabbit. You need to protect your tree trunks with something like black plastic drain tile so the rabbits don't do that. You could do something simple as cutting house wrap like Tyvek so its loose around the trunk and tape it to make a tube. That's what I do, but I have lots of Tyvek.