There are a couple in my area that I'm aware of. The bend in one tree is "aimed" at a natural spring approximately 1/2 mile away (fantastic water though it's been years since I had any from it). The other I'm still trying to determine if it is "aimed" at anything or is just a natural though damaged growth pattern.
The rock it's difficult to say though to me it just looks like some kids somewhen along the way started carving something clever.