I was thinking the State park marker was something rather historic. The park was first established in 1935.
I have seen the 1902 Crater Lake NP marker (SW corner) which dates back to 1902. Since the trail it is located near has been closed for a number of years, the visit is all that more nostalgic.
The purpose of this forum is to help people identify things they've seen while out hiking: wildflowers, trees, birds, insects, small animals, animal tracks, even geographical features like buttes or streams
Most markings, State Parks or otherwise that you find on trees are actually witness corners, not the corner itself, those are usually physical monuments like the one above, or even buried. Those tree ones are temporary and help define where the real one is.