Look like boundary trees to me.

Sometimes we put these along the whole boundary, sometimes just the witness trees near the corner stake.  Witness trees will generally have the blazed bark along with a plate, or nail with a medallion on them.

Its a rough neighborhood when you see graffiti like that, definitely a turf war through tagging. 🤡

In my area, orange paint on trees/fences/etc means "no hunting on this land" - maybe it's something similar?

You have some interesting responses.  Kat Palmiotti may have nailed it. 

In some states it's a warning to potential trespassers, known as the "purple paint statute".

Missouri: https://www.farmprogress.com/farm-life/what-does-purple-paint-on-a-tree-mean-

Pennsylvania: https://www.pgc.pa.gov/HuntTrap/Law/Pages/Purple-Paint-Law.aspx

Fred Griffin Florida Real Estate - this may help:
"https://content.ces.ncsu.edu/maintaining-forest-property-boundaries#:~:text=Marking%20Property%20Lines,the%20property%20line.

Land surveyors routinely “brush” or clear property lines during a boundary survey. Typically, a swath is cleared with a machete or chainsaw to allow for clear sight lines between survey points or stations. During the “brushing” of property lines, trees directly on the interior are often given one to three slash marks on the bark with a chainsaw. These marks are easy to locate once one knows what to look for. The combination of brushing and slash marks allows landowners to follow up the surveyor and paint or post the property line. Figure 2. Evidence of survey marks or hacks on line trees made with a machete or axe. Freshening or reopening them keeps them visible for years. Source: https://content.ces.ncsu.edu/maintaining-forest-property-boundaries

Could be possible trail markings

In my neck of the "WOODS" they do this to diseased trees to be cut down Fred Griffin Florida Real Estate .

probably ask a local.  We have paint on trees in my area.  It's yellow and it's along the lease strips of land.  One mark around the tree it's YOUR tree, two rings and it's THEIR tree.

If you go back hundreds of years (or more), these marking types established land boundaries quite well. However, if you cut a tree down, move a boulder and re-dig a valley, those boundaries can change. This mark means something but what?

Interesting post Fred. I don't wander into the forest much so I don't see these. Thanks for sharing.

Looks like someone is confused as to which tree is to be taken down.

And now I know more than I did before. Great question to which I have never given thought being a city guy. Thanks and thanks to those who answered.

Blazed lines kept freshly painted make good neighbors... like fences. Besides triple stumpage or more for timber poaching trespass... you could add a sign.. survivors will be prosecuted. I have seen "I own a gun and a backhoe". That keeps folks away... well off your prime forested woodlot stand.

Very interesting. Looks like you may have gotten an answer, Fred. It would be cool to know the history behind the still that remains on the property. We have back country moonshiner's in our Georgia family history.

Fred, in our state marking trees with purple paint means:

Posted:  No trespassing; Keep Out!