Get yourself a 2 ton come-a-long. Wrap chain a couple times around the bottom of that tree, hook chain to come-a-long, hook come-a-long to suitable tree, and start crankin'. See what happens. I've safely brought down numerous trees this way.
I'd caution you on cutting that root ball. Since there's no pics, this is purely conjecture, but cutting the root ball can cause the tree to slide backwards, can pinch your bar too, that'll whizz ya off for sure. Then you'll wish ya had another chainsaw to cut out the one that's stuck in there. Doesn't sound like your case though as your tree sounds like it's leaned over far enough to not slide backwards on you.
I've heard of guys killed when cutting root balls, you see, the root ball can stand back up when you cut through. In fact, I think it was a little girl killed not too long ago, she was standing near/in the hole and the guy cut the root ball and it stood back up and crushed her. Or, the tree can shift back on ya, roll over, or who knows what else. It can be exciting for sure!
You get a good come-a-long and 40 foot of chain or more and you can pull down most any tree safely, as long as it ain't a four foot trunk on it, haha.....HOWEVER
....., I've seen trees coming down smack limbs of other trees, or smack into other trees, and hunks of limbs go flyin'.....and I KNOW these can/have killed men before.
BTW, you got a hard hat?
I do
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