I suspect the blade is just for show, the larger branches are actually attached to the ground and pivot at the point where they attach. I remember reading it's like that because having them loose caused issues where they would get pushed by the truck's wheels, rather than just driving over it.
I've also attempted to move mud with a blade on a mod and it really doesn't work. So it will only work if they've made a lot of changes to the mud and branches, which I think is unlikely.
I belive thats the case too.