lumberjack
Young man on the go
If you put too much squeezing up high, you can blow out the bottom just the same.
On post 21, I would put one ratchet strap at the top white line and the bottom green line. I would make a turn around the tree before hooking it back to itself. A 2" ratchet strap ($13 at Lowes) would be fine with the extra turn. As I went up the tree, I would use a short rope to tie the two sides together, tensioning with a 3:1. That will put a little preload on the tree but more importantly keep your weight's horizontal vector transferred to the other side.
On post 21, I would put one ratchet strap at the top white line and the bottom green line. I would make a turn around the tree before hooking it back to itself. A 2" ratchet strap ($13 at Lowes) would be fine with the extra turn. As I went up the tree, I would use a short rope to tie the two sides together, tensioning with a 3:1. That will put a little preload on the tree but more importantly keep your weight's horizontal vector transferred to the other side.