Combining slash bundling with in-woods grinding operations

Conclusion
This study evaluated harvesting productivity and cost of a woody biomass recovery system using
a slash bundler. Productivity for different machines varied from 8 to 42 BDT/PMH, with a total
production of 280.7 BDT over 70.2 hours. Production cost ranged from $2.99 to $17.97/BDT for
different system components, with a total system production cost of $60.98/BDT at 28.95%
moisture content.
The bundler tested on ground based clearcut sites performed well producing 29-37 10ft bundles
per productive machine hour. Slash pile arrangement and material size were found to have a
significant effect on productivity of bundling. Pile class 3 (typical size material, side-cast piled)
was found to be the most effective pile type when considering bundling productivity, yielding
the smallest predicted cycle time (1.60 minutes).
Loading slash into bins was efficient and had a low cost of $2.99/BDT. Loading costs could be
inflated if the bundles were not located within one swing of the road edge because of increased
travel distance. The hook-lift truck effectively negotiated adverse forest roads and allowed the
removal of slash from traditionally difficult- to-access sites, without burning slash. Harvest sites
ideally should be located within close proximity to a centralized grinding site (< 5 miles).
Due to the complexity of variables and their effects on overall system cost and productivity, it is
apparent that operations like the one observed in this study require careful planning and strategic
logistical arrangements. System cost can drastically change with increased hauling mileage on
single lane dirt roads, due to slow traveling speeds (8 mph). The total system cost will increase
$3.07/BDT for every one mile increase in dirt road hauling distance. The cost of the fuel price
was found to have a tremendous effect on total system cost, every $1/gal fuel price increase
would result in a system cost increase of $3.52/BDT.
Forest biomass was removed successfully from previously harvested timber sites with poor
access issues, but the overall system production cost was still high. The high system cost is
primarily due to the poor system balance and the low level of production associated with being
an experimental rather than full scale operation. Appropriate pairings of machines may further
reduce system bottlenecks and greatly improve the system productivity which may further reduce
system cost.