Observations on the effects of rough-delimbing and load compression on harvesting system costs in fuel wood thinning.

In this study, the effects of rough-delimbing and load-compression in fuel wood thinning were investigated with the aim of evaluating the technical and economical efficiency of these processes compared to the extraction of un-processed/un-compacted whole tree parts. The time consumption and production of two harvesters and two forwarders were monitored in a field study of fuel wood thinning operations in Sweden. The harvesters either felled trees with an accumulating felling head and then cross-cut bunches, or trees were felled and accumulated with the harvester head and then roughly delimbed and cross-cut. The density of each forwarder load was calculated by measuring the length and mass of randomly selected wood piles and comparing to literature load-density curves. The literature data were also used for calculations on the effects of load compression. The results showed that load compression resulted in a 16% increase in bulk density and ca.5% reduction in harvesting costs, whereas rough-delimbing resulted in a 73% increase in bulk density and ca.12% reduction in harvesting costs.