Many times utilitys dont actually own the land they run across. Theres usually an easement placed on the deed to the land that gives them access to it, but the land owner still owns the property and everything on it.
If they happen to be cutting within the the road right of way it might be fair game, but if its beyond that, it probably belongs to the land owner. Either way, it wouldn't hurt to knock on some doors and ask permission. If they don't burn wood, they'll more than likely be happy to get rid of it.