What's happening to my apple trees?

Hello, I'm on my new homestead, and this apple orchard is already in. The trees were neglected for a year or so. The grass wasn't cut, no water, just ignored. So after getting the grass cut I found all the trees had that white plastic stuff wrapped around the trunks. It was tight on most of the trees and didn't look good. So I took it off. This is what I found under some of it. So I'm curious what is going on here and what if anything should I do? Thanks.

I'm no expert but this looks like mechanical damage, possibly from the plastic being too tight or rubbing.  Looks like the tree is girdled and is growing back from the rootstock.  The top of the tree is probably toast.   I'd Cut the upper part of the tree off, get the rootstock back to health and then use the apple variety you want by grafting.   You might want to use some tree wound or grafting compound to cover the cuts.  Make sure everything is clean.  I used dirty clippers to cut a branch off of a Pear tree and then went over the wound with tanglefoot.  I created a fungus problem with dirty tools.  

The plastic "protectors" did quite a lot of damage there, bark in the first picture was either rubbed off or rodents got under the protector and had a feast, the second photo is rub damage from the protector.

While those things are good there is a point where you have to remove them or damage like you are seeing happens.
Usually protectors are only used while the root system gets established.
If the tree in the top photo has any growth above the graft, it should make a comeback, the bottom tree will recover since the bark has healed over the wounds.

All the trees still look pretty good considering the damage to the trunks. All are still green and seem to be ok. I'll just let it ride and hope for the best. Thanks.

Something clearly girdled the bark on that poor tree.  You see this all the time with people who take a weed-wacker and try to clean all the grass away from the base of the tree, effectively stripping all the bark off and killing their poor tree.

That bark will never grow back.  Trees do not "heal" in the sense that human skin will grow back and replace bruised, burned or damaged skin.  All the tree can do is try to seal off the wound, or in the case of that second picture, the bark peels back and tries to create an edge that isn't open to further infection or insect infestation.

The best thing you can do is get a couple of new trees started because long-term, those trees are pretty compromised.  Once your new tries are 3 years old, you'll be able to pull those ones out.