When the bucket is fully raised, it's probably almost over the tractor radiator. I wonder if the tractor could be damaged? If a stump broke off, the but-end may come up hard under the tractor. Seems like there's also a good chance of a dead limb falling on you or the tractor when working that close to a trunk. I think I'd rather take down good-sized trees with a chain saw and worry about the stumps later.
Codes for service line here are 15' foot residential and 20' where farm equipment may be operated. Many service connections pre-date the codes and are lower. I can see how it would be easy to be concentrating on doing a job and forget about overhead service lines. A friend of my brother-in-law's was killed last summer like that, but while using construction equipment rather than a tractor.
I have to remind myself to check if my wife left the clothes line up or down. If I snag a line with wash on at the other end, I could end up looking like a ship flying a message. The message probably would be: 'It's time for dinner, and you're it.'