We have blaze marks that look like that. They're made to mark property lines. Three or four marks on the side means the line is on that side of the tree a few feet. A strip peel off both sides means the line is right on the tree.
I can see a blaze through the trees getting your attention. That looks to me like a drill hole. Have you found any more around that spot. They're should be some kind of sign of occupation, work, a road, or more sign left.
All the sign of occupation should be old old. In one of my sights I have a road that you don't even realize was there till you get on the bluff over it the you can see that it was indeed a ancient road.
Document these for your site. GPS along with any info you can gather from them ... they look like they're about gone.
Two or more uprights generally marked a location for trail trees, if that's what they are. Those two so close together though make me wonder. I have one site I took pictures of and shared on a Native American forum. I was told the "4" tree on my site, like the one in the foreground of y our picture, were clan markers. That only applies if it is a Native American site.
When I first saw this one, it looked like a directional marker. The first bend where it comes out of the ground is called the hip of the tree. Are those bumps or just some lichen growing on the hip?
Bumps on the hip of the tree were used by Native Americans as "messages" and told what the tree was pointing at. I don't know how to read them, but got the information from an interview done years ago. Some bumps gave warnings while others may have told of herbs or even plants for medicinal purposes.
Those are bumps. There's lots of trees that ain't bent around that have bumps. There's one down the hill about half a mile or more that's covered up with bumps about four five from the ground.