If you could get a hold of a good tractor with a front end loader, preferably a 4x4 thats all you'll need. I can raise the bucket up on mine ease up against the tree, put it in granny gear and push over tree's, I think the biggest Ive pushed over was about 10-12 inches thick. The trick to pushing a tree over is letting the tree do most of the work with the tree already being top heavy, a little persuasion and some steady force is all you need. Watch pushing over dead ones, the tops will break out and fall on you, I had a near miss with a dead pine :ohmy: :yikes: .
If you some how get your hands on a friends tractor borrow a disk implement and a landscape rake. Use the disk to tear up the trail then use the landscape rake to rake up roots and rocks. G@@d Luck.