I have 2 old but very heavy 8 foot chains with an old-fashioned ring on on end and an old-fashion hook on the other. I guess you could say they are 150 years old, but they can still lift a battleship. They get wrapped around the tree a foot or 2 up from every cut I make. A barber chair from your average 10 inch diameter tree likely can't get past that without me hearing something, even over the chainsaw. Back in those much poorer times than now, I think I got the "feel' of when I'm getting close to run-like-heck time. That tree is coming down and God himself can't stop it. My rule is, I wrap the tree, no discussion. Then I make my front angle cut, Then I back off and shut off the saw and watch the tree, and the wind in the branches. I make a judgement as to whether to go back and give it some back cut. Generally I go for the long play. I leave LOTS of hinge. I've got all day for that tree to come down. Besides, there's going to be a rope keeping tension the other way, So far, that system has given me some fine firewood. If my two 8 foot chains can't make 2 winds apiece around the tree a, then I'll find a bigger tree already on the ground. Better to be a firewood vulture, living off the dead ones already on the ground, than being buzzard food with my sister never knowing why I disappeared. I'm glad the good lord gave me those hard times way out in the country. Out there, living in a cabin all those years with a maul, an ax, some chain and a come-along, A very old used Craftsman 19" with the thumb oiler, and my Homeite 330. All alone. Here's my advice. You look up at the tree good and hard. Keep in your mind every second, that tree might be standing there not moving a muscle. But it can kill you. It won't be plucking is own pine cones and throwing them at you. That sucker can be laying across you so fast...
I lived it, just like I wrote it. Strangely, hard as those years were, they're priceless now. Getting killed by a tree. Nope, not me brother.