> Regularly trimming trees around the power line seems less expensive than boring through granite?

That's not going to do anything to stop ice from forming on the lines, which is a far bigger problem in the winter than tree falls.

The front range gets 100mph+ chinook winds, and late spring storms dump feet of heavy snow leading to what we affectionately call "treemageddon", during which town will be filled with the thunder of trees crashing down for hours and hours. It's not an ideal environment for lines on poles.

It's quite a battle as we also get gale force winds coming off of the mountains so often that it's not news, just a normal Tuesday.