I can offer this.....My uncle had one of those scoops and did the tree moving thing as one of his "get rich quick" schemes. He offered a 1 year guarantee. After he went out of business he told me this. Never move a tree that the scoop can't get 80% of the root system (the root system extends out from the trunk pretty much as far as the farthest branches). Never move a kind of a tree with a deep tap root (like say a buckeye) bigger in diameter than 3 to 4 inches or you will break the tap root.