Tecnologie per l'allestimento del legname finalizzato alla produzione di legna da ardere.

The global consumption of firewood is estimated at over 1.5 billion m3 per year. Use is especially intense in the developing countries, where it accounts for 80% of the total supply of primary energy The aim of the following work is to analyze the different firewood processing systems and to compare the different types of machineries, outlining the factors that influence their productivity. In particular this work describes two of the most important steps while processing firewood: the chopping and the splitting. These two steps can be carried out at the same time or in two different times and places. In the first part of this dissertation the most common firewood processing machineries are described, underlining the most important characteristics and technical features. They are divided between small machines, such as saws and splitters, and big sophisticated machines, such as firewood processors. Analysis performed shows that the productivity of firewood processor is greater than those used in the yards separated. In particular for the preparation of 1 m³ of firewood through the use of processor are needed about 7 minutes, while if the same work is dealt with using a circular saw and a log-splitter, the time the necessary time is between 24 and 46 minutes. It 'also showed that productivity can also be influenced by the type of processed timber: softwood and hardwood. For these reasons, the productivity obtained in northern Europe, where it is performed mainly with softwood is 7.3 m³/h, much higher than that recorded in the Mediterranean countries (3.2 m³ / h), which uses mostly wood of deciduous trees. The production cost of the firewood is strongly linked to the productivity of the forestry yard. By contrast, the use of processor involves high investment that can be justified only by operating with substantial quantities of wood. Furthermore, it was found that the skill of operators is not meaningful on the whole process of work. Important it is to choice the machine in function of work quality performed (processing waste should be lower than 5%) and safety for the operator.

Inoltre, è emerso che l''''esperienza e la professionalità dell''''operatore non incide particolarmente sull''''intero processo di lavoro e che i tempi improduttivi sono da attribuire soprattutto alla tipologia di macchina impiegata. Per sottolineare infine l''''importanza della scelta della macchina soprattutto in termini di qualità del lavoro svolto (gli scarti di lavorazione dovrebbero essere inferiori al 5%) e di sicurezza per l''''operatore. Si ritiene che quest''''ultimo sia un elemento fondamentale ma che purtroppo è spesso trascurato soprattutto dalle piccole aziende private che spesso optano per scelte caratterizzate da investimenti contenuti anche se queste vanno a discapito della sicurezza della macchina.