Abstract:
Based on data collected from seven commercial harvesting operations in Western Australia,
the study developed a productivity model for chain flail delimber–debarker–chippers (CFDDCs) used
in blue gum (Eucalyptus globulus Labill.) plantations. The tests covered 45 h and 3395 cycles, and were
conducted using time-study techniques. Despite the observational character of the study and the
dampening effect of multi-tree processing, the study yielded a viable prediction model for estimating
CFDDC productivity as a function of mean tree size, tree form, bark–wood bond strength (BWBS),
and machine type. Productivity increased with mean tree size on a logarithmic scale, and was lower
for poorly formed trees and high BWBS. Under equal conditions, a separate delimber–debarker
and a chipper were 10% to 20% less productive than the integrated delimber–debarker–chipper.
Productivity estimates were consistent with those reported in published case studies of CFDDCs
used in planted Eucalyptus. Neither this study nor any of the previous ones could offer a reliable
estimate of long-term machine utilization, which would be an ideal subject for future research.
