by adjusting the length of the tarp line? (same idea as a tree strap for hammock really...)
EDIT: this is for a crosgrain type of webbing. For other types with hardware/buckles, I personally would have 10 feet straps with buckles, and then use that to adjust for length between trees if I don't want to deal with adjusting the tarp lines....basically a V strap kind of thing wrapping around the trunk.
Bookmarks