Learn how to use a dead eye sling to connect a Port-a-Wrap to the trunk of a tree using a cow hitch or a timber hitch.
Dead eye slings are available at TreeStuff.com: https://www.treestuff.com/store/products.asp?category_id=78
How to use a Port-a-Wrap: https://youtu.be/B7jdk_yN9Ow