High lead logging is a method of
cable logging
High Lead logging in Western Oregon
Cable logging, also referred to as skyline logging, is a logging method primarily used on the West Coast of North America with yarder, loaders, and grapple yarders, but also in Europe (Austria, Switzerland, ...
using a
spar
SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...
,
yarder
A yarder is piece of logging equipment that uses a system of cables to pull or fly logs from the stump to a collection point. It generally consists of an engine, drums, and spar, but has a range of configurations and variations, such as the swing ...
and loader. It was developed by
Oscar Wirkkala. 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) attache ...
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
A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that ...
) 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
A guy-wire, guy-line, guy-rope, or stay, also called simply a guy, is a tensioned cable designed to add stability to a free-standing structure. They are used commonly for ship masts, radio masts, wind turbines, utility poles, and tents. A thi ...
.
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
Lidgerwood was a historic American engineering company famous for its boilers, winches, scrapers, hoists and cranes, particularly ones that helped build the Panama Canal. They later built logging yarders and aerial tramway
An aerial tram ...
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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