I can't
answer your question from
experience, but I think they'd have a good shot at climbing the tree without the support. When grown for the flowers for brewing, I'm told they are always grown on very tall wire trellises, but I think that's just because wire makes the cheapest tall
trellis.
Last year I planted some outside my bedroom window (which gets too much sun and drives up my A/C bill) in a tire planter on the ground. They grew OK from seed (which, like apples, you're never "supposed" to do because of genetic variation) but mostly they just multiplied as a ground-dwelling shrub less than 14" tall that expanded to fill the planter. I offered them trellises in the form of wire refrigerator racks screwed to the side of the building, which they spurned.
However this spring as soon as they greened up they just started exploding up the trellises. Currently they are at chest level and rising nearly a foot a day. Which gives me about three or four more days to string some wire from the top of my trellises (about 7 feet off the ground) so they can get up to the gutter, which is as tall as I'm going to help them get.
They are clearly using the trellises very aggressively, but it doesn't really look to me as if they need more than a little help. I'm not saying they could have climbed the steel siding without anything, but it does look very much like they would have been happy with a shovel handle leaned up. Which makes me think your dead trees ought to be plenty.