Recently Tinny at minibulldesigns has posted some video on hanging with out using tree straps- just the whoopies wrapped around the tree. He maintains that straps are hammock "Dogma" and are not needed when hanging a hammock in the usual way. When challenged he posted another video with an "experiment" showing that his 180 body only generated 160 pounds of force on one end of the hammock. He claims this could not hurt the trees. In his final video test today he strung the hammock as straight across as he could get it and only generated about 210 pounds of force. He was careful to note that you didn't have to have it super taught to string it straight.
So if you are in the 180 lb range and hang your hammock properly at about 30 degrees is it ok to not use tree straps. ( I calculated his 160 lb's of force put about 50 lb psi on the tree. Is that enough to hurt the tree?