Combining slash bundling with in-woods grinding operations

Time study data was collected to calculate hourly production (bone dry ton (BDT)/productive
machine hour (PMH)) using standard time study techniques for each element in a machines
operation cycle by stop watch (Olsen et al. 1998). A bundling cycle includes traveling to the
slash pile, followed by multiple grapples and swings of slash to the in-feed table, and ended
when the bundle produced was cut free from the machine. A loading cycle started from traveling
to a bundle, followed by swinging empty to the bundle, grappling the bundle, swinging loaded
back to the container, and ended by compacting bundle into the container. A hook-lift trucking
cycle includes traveling empty to the harvest unit, positioning the truck for loading, loading a
container filled with bundles, traveling loaded to the centralized grinding site, and
unloading/dumping the bundles. Three types of delay time, including operational delays,
mechanical delays and personal delays, were recorded.
Regression models for delay-free cycle time were developed using the pre-identified independent
variables associated with each cycle. The collected time study data were screened for normality
and outliers using histograms and residual plots, and were used to develop predictive equations
by running multiple regressions using ordinary least squares estimators, performed in R 2.4.1
statistical software program (R 2006). The final predictive models only include variables that
were statistically significant (p-value