Citation

Gaskin JE. Int. J. Ind. Ergonomics 1990; 5(3): 211-218.

Copyright

(Copyright © 1990, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This report details the results of investigations into two methods of chain saw delimbing in clearfell of Pinus radiata in New Zealand. Motor-manual delimbing in New Zealand logging typically involves the logger walking along the top of the log using the tip of the guide bar to sever branches (conventional technique). In an attempt to reduce the amount of bending required, longer guide bars than are necessary tend to be used. Invariably, the operator's spine is still bent close to 90 degrees from the vertical for the majority of the time. Considerable research and development has been invested in adapting the Swedish style of delimbing to New Zealand conditions (alternative technique). This involves the operator walking alongside the log using a lighter saw equipped with a shorter guide bar. A comparison of the two delimbing techniques using a static biomechanical model, and the collection of heart rate information was carried out on an operator working in the clearfelling of 30-year-old Pinus radiata. Using the alternative technique resulted in a significant reduction in compression and shear forces at the L5/S1 disc. Heart rate information collected at one-minute intervals while the operator was delimbing using each technique showed no significant difference between the two techniques.