I'm running a home made 80m dipole but out the front of the house I didn't have enough room. To run a line over the top of the tree is difficult, the highest I've got was by standing on a ladder with a squid pole.
The obvious answer is some sort of slingshot to fire a line on a sinker over the tree and then pull over a stronger cord. It worked out pretty well and after three shots I was happy with the height.
I need stronger fishing line, the stuff that came with the $12 reel is very stretchy, also the length could be longer as the reel gets in the way of the rubber band pull back.
It's amazing how many people drive and walk by when I'm attempting curious ham radio related activities out the front of the house, one guy kindly offered me a saw as he thought I wanted to remove a dangerous branch.