Electricity will stay in power lines unless
something or someone gives it a path to the ground. Birds can sit
on high-voltage power lines because they are not touching the ground
or anything in contact with the ground. So electricity stays in
the lines and does not go through them.
Trees are in direct contact with the ground.
So if a tree branch contacts a high-voltage power line, electricity
will leave the line and go through the tree. Trees that are in contact
with secondary power lines and service drops pose a much smaller