Update.
I bought 50 acres, about 35 pasture and 15 woods. The pasture is overrun with wild Bradford pears; probably over 1000. I bought a Kubota M7060HD12. I have done done a lot of bush hogging and now am starting to work on the trees. I decided to go with Dougherty Forestry Manufacturing's Turbo Saw. The saw mounts on the Tractor's 3 point hitch. I have a grapple on the front of the tractor. I took the saw out to the property for the first time today. I cut the tree and ground level, then my wife paints the stump with Garlon 3A herbicide, then I stack the trees in a burn pile with the grapple. We cut 50 trees today, ranging from about 2" to 12". We have a long way to go, but I'm really happy with the Turbo Saw.