The "high lead" feature is added by elevating both lines near the winch or 'head' end.
Early on, it was customary to trim and top a tree making it into a 'spar pole' or 'spar tree' for the purpose of supporting the head blocks but gradually the use of wooden spars gave way over the 20th century to the use of steel spars stood up for the purpose.
[1] The reason for elevating the lines (cables) at the head end is to assist in pulling the logs free of obstructions on the ground.
Also if the trees are being partially lifted as they are transported it is less disruptive to the ground which can be an environmental issue.
High lead is a popular method of logging on the West Coast of America.