Productivity and energy balance in the conversion into high forest system of a Quercus cerris L. coppice in Central Italy.

Abstract. The work was carried out in Caprarola (Viterbo, Central Italy), in an aged Quercus cerris L. coppice positioned in hill zones, with 45% average slope. Harvesting was conducted according to the shortwood system (SWS). Felling and processing were done by chainsaw, while the bunching was performed with three different systems: in Plot 1 with mules; in Plot 2 with a tractor-mounted winch; in Plot 3 with poliethylene chutes. Logs were then forwarded to the roadside landing with a farm tractor, equipped with front and rear container bins. Finally, transportation from the landing to the company depot was performed with a truck and trailer unit. In order to speed up loading, a tractor equipped with a loader was used during this stage. On the basis of time consumption, product output and energy consumption, the Authors estimated both the productivity and the energy balance obtained with each system. The best extraction productivity (PSH0) was achieved in plot 2 (winching, 0.8 td.w. h-1 worker-1), while the lowest one was achieved in plot 1 (mules, 0.5 td.w. h-1 worker-1). The energetic efficiency was high in all the plots (on average, 97.6% ± 0.3). No correlation between time consumption and energy efficiency was observed. For Plot 3, high productivity, low time consumption and high system efficiency suggest that chutes are the most efficient bunching method from the energetic viewpoint. As the site was in a Nature Reserve and chutes are known to minimize damage to soil and seedlings, this system is to be recommended from both the energetic and environmental point of view, provided that the wood can be extracted downhill.