@gollum,
gollum wrote:Is there any prohibition on the planting of a tree that when grown could fall on a power line?
I doubt it. But I suppose it depends on what regulations your local government has passed.
gollum wrote:Is there any requirement to trim or chop down a tree that could fall and interfere with a power line?
Back when I was a teenager the power company notified my neighborhood that they would be poisoning any trees by the road that threatened their power lines.
If we wanted to trim trees or chop them down ourselves, we were free to do so before they came through and dispensed the poison.
Back in the woods on our property a few small trees had started to grow under the power lines by the road, and my parents cut them down in order to prevent poison being dumped there.