Any power company will tell you where to avoid planting trees, this includes anywhere in the utility easement and anywhere that they may grow up under overhead service lines. People of course ignore this because they have no common sense. Yes in many cases the trees were planted by previous property owners but ultimately if you own a tree and it is causing a problem for your power, phone or cable, why wouldn't it be your problem? Many power companies will do minimal trimming because of the dangers associated with downed power lines, but cable and phone lines are much less likely to be a danger if downed, just a service loss. Unless the trees are actually interfering with the distribution system, don't expect the telco or cableco to do anything. They will replace the service drops when they get pulled down by trees, but won't pay to maintain your trees for you.