[Eric 951]

You could also run 5/16" wire rope between the trees using Crosby clamps to secure it to itself once looped around the branches. Fit a rubber sleeve over the wire rope where it contacts the branches to prevent it from digging into the wood. Tension as necessary, and use (2) additional Crosbys on either side of each swing rope(total of (4) to keep the swing centered on the cable, use oversized washers between the swing hangers and Crosby to allow smooth movement, and use a carabineer to attach swing rope to wire rope.