- Cable logging
Cable logging is a
logging method primarily used on the West Coast of North America withyarder , loaders andgrapple yarders .The cables can be rigged in several configurations.
There are two classes.
#
High Lead , in which a simple loop of cable runs from theyarder out through pulley blocks anchored to stumps at the far end of the cut.
# Skyline, in which a carriage, pulled by hauling cables, runs along a skyline cable, providing vertical lift to the logs.Into this there are varieties of loading systems.
While skyline logging requires additional setup time, the vertical lift of the skyline allows faster yarding, which can outweigh the additional labor costs, especially on larger harvest units.
Since the 1980's Grapple
Yarders have become popular.Skyline and grapple yarding, however, require more complex and expensive equipment. A traditional highlead or gravity system will function with just two cables, a skidding line and a haulback line. As the names imply the skidding line is used to drag the logs in, and the haulback line is used to drag the skidding line back out for the next turn (or group of logs).
A skyline system will add a third line---the skyline whose function is to hold the skidding line and the haulback line off the ground or 'in the sky'.
The yarder itself is located on a landing, a flat area on top of the ridge that is being logged. After the trees are retrieved by the yarder, the limbs are bucked (removed) and the logs are then placed in piles awaiting transport.
ee also
*
Washington Iron Works Skidder
*Swing yarder External links
* [http://www.cnr.vt.edu/visser/cable_logging/index.htm Cable Logging]
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