Productivity and Costs of Harwarder Systems in Industrial Roundwood Thinnings

Abstract

In several studies, the harwarder has proven to be a more cost-effective wood harvesting system than the traditional two-machine (harvester-forwarder) system, especially when the average stem size of the marked stand is relatively small, the removals per hectare/stand low (i.e. the harvesting site small), and the forwarding distance short. One of the strengths of a harwarder is considered to be the lower relocation costs compared to the two-machine system. The time consumption of harwarder relocations have not, however, been reported in the previous harwarder studies. Metsäteho Oy conducted a follow-up study of harwarders in industrial roundwood harvesting, and also investigated the relocations of harwarders. A total of five – three Ponsse Wisent Dual and two Valmet 801 Combi – harwarders were examined in the follow-up study. The amount of harvested industrial roundwood in the study totalled nearly 30,000 m3. The cost calculations showed that the harwarder system is more competitive than the twomachine system when the average stem size of the marked stand is relatively low, i.e. less than 110–170 dm3. Furthermore, harwarders were the most competitive at low-removal harvesting sites. The proportion of the total working time of harwarders used in relocations between harvesting sites was 2.5%, and the effective relocation time was, on the average, 1.3 hours/relocation. The study results underlined that it makes sense to harvest relatively small-removal and small-diameter thinning stands marked for harvesting with a harwarder while, conversely, it is more worthwhile to harvest sites with larger removals and trees using a two-machine harvester-forwarder system, thereby raising the profitability of forest machine business.