Feasibility of Excavator-Based Harvester in Thinnings of Peatland Forests

In the next twenty years in Finland, annual cuttings on peatland forests are foreseen to increase by up to 30 % of the total cuttings. Cost effective harvesting methods on low yield peatland forests coupled with low ground bearing capacity are required. One solution to improve the feasibility of harvesting could be excavators tailored for forestry use and equipped with a harvesting head. In the study, cost competitiveness and productivity of the excavator-based harvester were investigated. The cost analysis focused on operating hours of harvester use, shift arrangements and purchase prices for the base machine and harvesting equipment when the base machine was used partly as a harvester and an excavator. Results were compared to conventional wheeled harvesters. If the base machine is used more than 3 working months as a harvester in addition to normal (6-8 months) excavator work, the harvesting method would be cost competitive compared to purpose-built harvesters (if 1½ and 2 shift arrangements were used). The 25 % increase of the base machine's and harvester equipments' purchasing costs did not eliminate the cost competitiveness of harvesting, when harvesting was carried out in 1 ½ shifts for at least 4 months. It would be feasible and profitable to invest in harvesting equipment for the excavator and therefore diminish the winter lay-days of the base machine by utilizing it in logging operations. Conditions on peatland sites mean that during the winter time the use of the excavator-based harvester is ideal, when the utilisation of all logging machines is at its highest