In Back O' Beyond, two glitched trees can be found. The lower part of the tree's trunk is gone and the player can easily see inside the tree and even pass straight through it.
The tree could've been left behind by Rockstar's bug testing team or the gameplay testing team, as this is the only tree with no lower part of the trunk. Another possible explanation is that Rockstar left it there thinking that the players will not be able to spot it because the area of Back O' Beyond is a forest area and it has many trees and other wild bushes.
There are two glitched trees, except the other one cannot be passed through, and is closer to the ground.