I just ground out a giant water Oak root ball that was head high. And not only that to make matters much worse it was under a fence. A chain link fence so we couldn't just grind it. Fortunately my client's father came out and helped us take the fence apart and we ground the stump and regretted with the skid loader so that he could fix fence would save him a world of trouble. Both Father and Son thanked me and told me I did a great job. It was my pleasure