Why do they plant huge trees under power lines

These are heritage trees so can’t be removed but they come and chop them back every few years.  I’m not sure if the trees were planted before the lines went in but when they die they plant more of the same. I’ll put it in for silly Saturday. 

I did about 15 minutes in the garden planting some pansies. Can’t believe how out of breath I was after doing very little. I was able to kneel down for a short time which was good. It didn’t feel comfortable but was achievable. Extra shows my first bulbs flowering. They are early white jonquils.