Chopping up trees

What is it with taking a hatchet to a living tree at designated campsites and chopping a wedge out of it? Not to mention chopping standing trees that may or may not be dead, when you can walk a few hundred yards and find downed wood everywhere? And driving nails into living trees to hang stuff?

I keep seeing this at designated campsites. Is there a lot of this in other parts of the park (I'm seeing this in the Northern sections)?