We've written before about electric chainsaws, but this is even greener. The hand-powered chainsaw doesn't use any fuel, will never run out of batteries, and is easy to carry. Of course, it's not going to be suitable for clear-cutting hundreds of acres of rain forest, but if you're doing that then you're not worried about the environment anyway. A small weight allows you to throw one end of the rope over the branch, but it might take some maneuvering to cut the branch without standing underneath it - a fine idea until you cut through that last little section and gravity stops being your friend.
One Boing Boing reader, Dan, has pointed out that these have been around a while, "I have had one of those 'new' chain-on-a-rope saws for almost twenty years. Exactly the same as pictured - yellow rope, red throwing bag, metal plate hanging off one end of the chain. It works, but it is by no means 'effortless'." OK, so maybe it isn't new, but it's still a great idea. ::Hand Powered Chainsaw via ::Boing Boing