Not to rain on the parade of fun tinker ideas, but......
I don't think either of these ideas has any hope of being practical. The load forces would be tremendous. A fixed mechanical gin pole, similar to high lead logging, HAS to have guying to withstand the incredible side loading. I can, however, visualize the success of a device to allow reaching branch ends of a topped tree. It would be safe for life support, but you wouldn't be able to lower off the same pole, unless it was ultra strong and guyed....and VERY securely strapped to the tree. And in such a real world scenario, (previously topped tree with huge side branching)it might be hard to find a straight area of trunk to lash it to.
Besides, realistically, in real world tree work, the need to lower wood is only occasionally needed. I dont know about you guys, but I usually find a safe alternative. For instance, In conifer removal, I try to get 30 foot logs for export, and 16 minimum. I've dropped huge trees across asphalt, right on top of sidewalks, and directly onto nice lawns, all with little or no damage. Plywood, tires, (up to 75, and sometimes laced together)bridges built out of wood, conifer brush piles are most of the tricks. Of course, cranes are better, if the job is safer and better done that way, and if access allows, but usually costlier......not always tho due to the labor saved.
Presently, though, we finish the huge maple Monday. See the "Technical removal" thread. We're employing just about every high tech trick on that one!! And I just sold a 30" dbh very brushy hemlock touching a house. We'll speedline the brush over the house, and likely the wood too, using our 31300 lb plasma line. The low branches will be mid tied, with speed line above, thus creating a bight. We'll lift them up and/or around with z pulleys, chain saw winch or chipper winch, and zip em right over the house. Piece of cake compared to the maple. For this technique, I want to control the amount of bite, so I install a few temp redirects on my way down to the lower branches. It is a bit tedious too, as some higher branches have to be cut to make room to lift others. A plus, is that the customer wants a habitat tree created, so we can leave it 8 -10 feet above the roof!! I think 5 hours will do it, and the price is $1250, not bad at all. Plus the chips stay, and the job is 6 blocks from the shop. We'll need two ground guys, plus another climber doing a bit of thinning on a large white pine, no gman needed, for another $300.
