I think this is cool and green. I would want something that is bicycle powered but more stable and have a less risk of falling off. Perhaps a small platform with guidelines to keep it from moving from side to side and/or less likey to tip.

.... and whats more: It's not even controlled by and iPhone!

I think this could be a launching point for the sweatpunk aesthetic

Cool comments :-) The ultimate idea might be a small platform with the pedal mechanism in the middle. Or, for the lazy among us, (me) a water and hose mechanism so you just hop on and use a tap on a hose that runs up to the water ballast tank. Let water fill it until you start to rise! Lazy AND awesome! Perfect combination. Maybe also a beer holder. I like drinking while admiring my handiwork.

needs to be tandem, for when friends pop over

In my humble opinion, you are making a simple problem much too complex. With a simple platform that is attached by rope or cable to a counterbalance weight, you can use the weight to help you pull yourself up with almost no effort. Look at how this was done in dumb waiters. Even vertically-opening windows have counterbalancing weights.

E.T. Phone home. Maybe add some ratchet or catch to hold bike if descent not controled by brake. Some means of preventing use my someone who has no idea how to use the thing safely. OSHA would puke no matter what you do. Pretty darn nice in my opinion.

y not rope ladder?

One wonders how the tree itself will fare with the friction mounted treehouse - since a tree's growth entails adding layers ("rings") each year is it possible that the bracket surrounding the trunk will eventually cause the tree to die? This is what happens to some trees in the Amazon jungle when vines essentially strangle them.

I really dig the Swiss Family Robinson vibe. He must not have a fear of heights. I have to agree with Les Stagg that the bicycle is unnecessary but it does have a kind of cool factor about it. What would be really neat is if he could build an entire house using the the neighboring trees as further supports. Why not actually live up there.