I have some argutas growing up ash trees and each year they keep
pulling the tree down closer to ground. We still have to get on a
ladder to get the top ones but it has actually worked out to be quite
manageable. These are ones that I don't prune too much, pruning would
be a nightmare.
I've been using old metal bed springs sideways bolted on to 2 tposts
and they make really secure trelllising at about 4 feet high for the
ones that I've been pruning.