I am wondering why a strap suspension directly around the tree—perhaps with a couple wraps—cannot be used with the marlin spike hitch and one toggle, but no second “rope” toggle or other hardware.
Please see Grizz’s video at precisely 7 minutes, 55 seconds:
Notice that he is showing how to wrap a single rope line around the tree strap toggle and using a second toggle for the rope.
Why would one not simply have a single line permanently attached to the hammock, bring it around the tree once or twice (the line could be a rope, a la Hennessy, or a tree-saving 1” strap), back down parallel to the ascending line (to the tree), and then do precisely what Grizz did in the video with his rope toggle: put in a single marlin spike hitch. The adjustment for tension is simply to put the spike hitch at the proper spot in the rope/strap.
This would seem to have advantage of a truly single line (strap or rope) suspension—just one line from hammock, around tree, then toggle/spike hitched to proper length. Need only one toggle, or better yet, a trail stick. No descending rings, carabiners, Dutch clips, Tri-glides or second ropes (one from hammock (e.g whoopie) and another one from tree (e.g treehugger)) required. No knot tying (other than learning the marlin spike). Don’t even need a sewn loop in the rope or strap—just a free end.
I tried it tonight on a chair back, and it holds very firmly (I did not sit in a hammock) and shows no sign of slippage and is adjustable.