High lead logging is a method of
cable logging using a
spar,
yarder and loader. It was developed by
Oscar Wirkkala Oscar Wirkkala (; October 30, 1880 – January 25, 1959) was a Finnish-American logger and inventor who spent much of his life in the Pacific Northwest.
Background
Oscar Wirkkala was born in Kaustinen, Finland. His father Abraham and brother Andre ...
. It is accomplished with two lines (cables) and two
winch
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable").
In its simplest form, it consists of a spool (or drum) attac ...
es (or cable drums). The mainline or yarding line extends out from one winch, while a second usually lighter line called the haulback line extends out from the other winch to a 'tail block' or pulley at the tail (back) end of the logging site, and passes through the tail block and connects to the main line. Butt rigging is installed where the two lines join and the logs are hooked to the butt rigging with chokers. The procedure is to wind up the main line and the logs are pulled in, wind up the haulback and the butt rigging is pulled out for more logs or another 'turn'.
The "high lead" feature is added by elevating both lines near the winch or 'head' end. This is accomplished by running the lines through a block (
pulley) called the "head block" because it is on the head end of the project. 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. In any event the spars are supported by a number of
guy wires.
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.
First used in 1904, with
Lidgerwood winches, and a spar tree.
References
External links
High-lead Logging on the Olympic Peninsula in the 1920s-30s
Log transport
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