So, we know that dogs are creatures of habit. If they know a door is there, they won't go through the opening if you remove it. Now what has happened here is that the owner had cut the branches of the dog's favorite tree. The dog used to jump and grab onto the branches constantly as a fun play thing for the dog. Then, as the owner of the video said, "for days now" the dog has been trying to jump up and grab branches.

Poor guy.