There are many ways of hanging a hammock and this post describes how to use the farrimond hammock hanging technique. Also see how to hang a hammock with a pair of rings and using whoppies.
The great thing about this technique is that no other hardware is required, just some para-cord. Either tie a farrimond hitch at both ends or use a fixed lashing at one end, like the evenk hitch and an adjustable one at the other – the farrimond hitch. Both these knot are quick release but neither are particularly east to tie. The downside with using this technique is that if the farrimond is not properly cinched, the knot can slip. Also, this technique can damage the tree. Whilst the evenk hitch can be wrapped around the tree a couple of times to spread the load, wrapping the farrimond around the tree creates enough friction to stop the knot from being adjustable.