Grace Manufacturing makes the tree terminator. It is the toughest attachment I have used. There are two sizes for larger trees, 12 in. and 20 in. I don't like the 5 in. shear. These shears are heavy 1250 to 1600 lbs. but tough as they come..
There is a tool to pull up small trees but I can't remember what it's called, kinda like a stake puller. Someone had the site on the tool forum at that other place. You might ask Che she might know of it.