A feasibility study on the performance of a harwarder in the thinning of small scale forests in Ireland.

Abstract

Private forest plantations in Ireland, if properly managed, have the potential to generate significant amounts of harvestable timber over the coming decades. However, the average size of private plantations is just 9 ha, therefore the identification of compatible, economic harvesting systems requires careful consideration. A feasibility study was carried out to compare the machine operation and movement costs for a harvester-forwarder system and a harwarder system (an integrated harvester and forwarder on a single machine base) for projected harvesting over the period 2020-2025 in a selection of privately-managed forests in Co. Wexford. Sensitivity analysis was carried out to determine the combination of factors that could make the harwarder system more cost-effective than the harvester-forwarder system. The results showed that if the harwarder and the harvester-forwarder systems are used on all sites, and if stands with attributes that favour the harwarder system are not pre-selected, the harvester-forwarder system was more cost-effective. However, the harwarder was more cost-effective on sites with small harvesting volumes (<100 m3). With a reduction of 10% in the operating cost of the harwarder system (representing the expected rapid technological and operational development of this new concept), both systems broke even, while, if only those sites with smaller harvest volumes were considered, the harwarder system would outperform the harvester-forwarder system. Management of the forests to establish tight harvesting clusters, by changing the thinning year of some of the stands, produced a marginal cost advantage for the harvester-forwarder system.