I saw something similar to this on you tube and had to try it. Not my idea but when I went back on you tube to try and find the vid to give the credit I couldn't find it.
It uses 2 poplar poles, to coated wire cable dog chain runs 20' each, 2x 1/4"x 4-1/2" bolts, 2x cable clamps, and four 3'x5/8" pieces of all thread with nuts and washers used as stakes. I have some other stakes for different kinds of ground but I have slept on this 10+ times and it hasn't sagged or dropped me on the ground.
Would also work great in a situation where you only have one tree