Some bushes can be a real pain. Japanese quince looks something like that and I tell you it has a rootwad the size of the plant it'self.
I see that you have some other good size trees there. When I have place to anchor a cable to besides the pulling unit this really can give you an advantage.
By using what is called a luff here in the northwest you can pull 4X the straight pull of the tractor.
Take two pulleys and lie them in front of the bush, tree you want to pull. Take a cable that will cinch up on the bush and attach it to the pulley nearest the bush. Attach a cable to the second pulley, run it through the one near the bush, and take it to something solid, put a few wraps on it and take it back to the second pulley and put it in it. Hook to the end of the cable and pull easily. the pulley nearest the pulling unit will move twice as fast as sthe one on the bush. You may have to reset them once you have pulled a ways. You will find that you will have incredible power in this fashion. If you need to you can put one more block in line with those, that gives you 8X the pull. Just be sure your deadman can stand the strain. You may need to use multiple deadmen but not for a bush that size.
Be sure that when you are pulling, that there is no one inbetween any of the cables and that you are using large enough lines. You can exert a lot of pull in this configuration.