Abstract
Different logging systems (or harvesting systems) can be used for wood extraction. Cable logging system is typically carried out on steep slopes and other rough terrain. In these contexts, also cable yarding can be an efficient and effective harvesting system. Ninety-five per cent of timber production in southern Italy comes from terrain classified as very steep slope, limiting the use of machines for ground-based extraction. Cable extraction is a desirable alternative to either a skidder or forwarder on a sensitive site.
To each harvesting system a different environmental load is associated depending on machine productivity and site characteristics. In this study, three different logging systems were analysed and compared using the Life Cycle Assessment approach. The compared logging systems are characterised by felling with chainsaw and three different extraction methods: by farm tractors equipped with a winch; by a skidder; and by a cable crane. The Full Tree harvesting method was adopted for both felling sites; trees were felled and transported to roadside with branches and top intact. The functional unit is 1 m3 of wood; the system boundary involves all the operations carried out in the forestry (felling, bunching and extraction) and all the related inputs (diesel fuel, lubricating oil, capital goods such as chainsaw, tractors, skidder, cable yarder) and related emissions. Inventory data were collected in three different test sites located in southern Italy and concern working times, productivity, wood yield, fuel consumption. The cable yarder shows the worst performances for 7 of the 8 evaluated impact categories. The use of skidder shows a lower impact for 5 of the 8 evaluated impact categories while, for the remaining 3, the best performances are achieved by the logging system in which tractor is used. For climate change, the impact is equal to 8.57, 8.04 and 10.46 kg CO2eq/m3 for the harvesting system with extraction carried out using tractor, skidder and cable yarder, respectively.
