Analisi di alcuni cantieri forestali per la raccolta di legna da ardere in Val di Susa

ABSTRACT In recent years the demand for wood used for heating has increased significantly because of rising costs of fossil fuels. The production costs of firewood are mainly related to the costs required for felling trees and wood extraction. The aim of this work is to analyze three forestry yards set up in the Susa Valley for firewood harvesting. The yards were different in machinery pools and for the working methods used for wood extraction. In the first site, located in the territory of Meana di Susa at an altitude of 1650 meters, a tractor mounted winch was used for hauling wood and a tractor equipped with front loader and trailer was used for loading firewood and carrying it to the storage center. In the second site, located in the territory of Venaus, a small craft made cableway was used for wood extraction and a transporter was used for carrying firewood to the storage center. The third site was located in the territory of Clavière at an altitude of about 1820 meters: here a horse was used for log bunching and log extraction. The comparison between the sites was based on the analysis of the time and productivity at work and their energy and manpower needs. The survey of the operating times was conducted by referring to the ¿Instruction Manual for the relief of work time and productivity in forestry works¿ - Notebooks of the Institute of adjustment and forestry technology, Faculty of Agriculture, University of Florence (Berti et al, 1989), using a professional centesimal chronometer. The data have shown that, in all sites, the production times are always higher than 70% of the total time required for felling and logging operations and the primary cause of downtime is due to the breaks of the worker for resting. The highest daily productivity of the work has been obtained in the site where a cableway was set up (3,6 stere meters / day) while the lowest one (3,1 stere meters / day) was obtained where the horse was used for logging. The main demand for labor (4,07 hUL / stere meter) has been found in the yard where a winch was used for hauling firewood: this is due to the time necessary to prepare the loads and to bring the rope back to the hooking site. This yard was also the one that showed the highest energy needs per unit of volume of wood harvested (76,14 kWh / t), because of the use of two high power rating tractors. The use of the horse was less productive than the use of specific machines, but thanks to its remarkable ¿low impact on the environment¿, working with a horse could be useful for bunching and skidding in parks and protected areas where the priority is not to be found in the remuneration of the work, but in the land conservation.