pictures are worth a 1000 words! any pictures of tree/bushes you are trying to remove? picture of tractor?
what are you wanting overall? just remove so you can mow? just to kill them and get rid of them?
how many are you wanting to remove? other?
it burred clear down at the bottom of list of forums "land clearing" forum
Land Clearing lots of posts on dealing with trees and stumps.
some deal with old tire rim. others deal with a A frame. to help create a pulling up force vs pulling over force.
others deal with leaving 5 to 6 feet tall stump left on bigger trees, and push with FEL (front end loader) or pulling over with chain near top of the stump that is left (uses the stump extra height as a lever to pull root bulb out)
others deal with renting a mini excavator.
others deal with renting a SCUT (small compact utitly tractor with backhoe) and digging trees out with backhoe, and using the FEL on a SCUT to fill holes back in.
some deal with a sub soiler, and driving around the tree to cut the roots up.
others use a stump bucket for a FEL or skidsteer.
=============
be careful regardless if you use chain, or cable, both can and will break. and can be deadly. when they do whip back.
if using chain, you can weave a smaller size rope through the loops. and leave rope loose. so if chain breaks. the rope should help hold the chain in place vs whipping back at you.
using heavy blankets over chain can also help.
but regardless try and keep chains and/or cable as short as possible within reason. and have second person around for just in case something does happen.