Chip truck utilization for a container handling chipper truck when chipping logging residues and the effect of two grapple types on chipping efficiency

摘要

Most forest fuels harvested in Swedish final fellings are forwarded to a landing, and chipped before transport to the end user. Chipping on landing is usually done with a large chipper mounted on a forwarder, an alternative is to use a chipper truck which combines chipping and chip transport. These are an economically viable alternative where transport distances are short. Container handling chipper trucks (CCTs) were introduced 10 years ago, and their advantages include better utilization of the chipper and more economical road transport of the chips than ordinary chipper trucks. A CCT was studied to evaluate its utilization and to determine if the choice of grapple on the CCT or the preceding forwarder influenced chipping productivity. Results showed that average productivity varied between 9.3 and 13.5 odt PMH0 depending on choice of grapple. A standard residue grapple was the better choice for the CCT, while residues forwarded with an asymmetrical grapple increased chipping efficiency. One-sixth of the work time consisted of delays and half of that time was spent waiting for empty containers. By careful planning of operations and adjustments of the number of container trucks in the system total waiting costs can be reduced.