Source: Dr. Reino Pulkki, R.P.F. Lakehead University, Faculty of Forestry | HARVESTING METHODS AND SYSTEMS DEFINED |
The objective of this paper is to generally compare the advantages and disadvantages of cut-to-length to tree-length and full tree harvesting methods and systems. Since there is considerable misuse of the terminology related to harvesting methods and systems they are briefly defined and described. The various equipment configurations and application of the methods to silvicultural systems are then presented. Finally, a one-grip harvester/forwarder system is compared to a conventional full tree system with feller-buncher, grapple skidder, stroke-delimber and slasher. A tree-length system is not considered since it lacks the clear advantages of the other two, with the exception that when compared to a full tree system the slash is distributed over the cut-over.
In any case, the choice of a harvesting method and system depends on the form of wood required at the receiving mill. For example, if a company is geared to accepting only tree-length wood due to the use of portal cranes, etc., a shift to a cut-to-length system would be a monumental change in wood receiving and handling at the mill. For this reason the comparison assumes either tree-length or log-lengths can be received at the mill. Also, it is assumed that roundwood is being delivered to the mills, thus chain flail-delimber-debarker chipper operations are not dealt with in this paper.
A harvesting method refers to the form in which wood is delivered to the logging access road, and depends on the amount of processing (e.g. delimbing, bucking, barking, chipping) which occurs in the cut-over. The different harvesting methods are: