Appraisals on poplar harvesting methods through energy conservation efficiency

As renewable energy demand Increases, SRF poplar cultivation is getting more and more Important in energy production as a valuable plantation for farmers in Italy. While the consumption of wood fuel is spread during all the year, SRF harvesting takes place normally between December and March: storage between April and November is therefore necessary, pointedly concerning the energetic quality of the material. Today three different harvesting methods are available, turning out respectively whole plants, chunks and chips. Some elements, such as weather conditions and microbiological activities, whose effects are not easily manageable, always produce a dry matter reduction, hence energy loss. Aim of this work is to point out the Influence of harvesting method on energy content preservation, through the control of the product dimensions. To evaluate the energy preservation of the products obtained with three different harvesting equipments, piles were built using respectively whole plants, chunks and chips. A measurement of the energy content of the SRF poplar cultivation was made during the harvesting, on late February 2007. Weather conditions during the storage period, temperature, precipitation, humidity and sun radiation were registered. Temperature inside the piles was also monitored at different heights. At the and of October 2007 the piles were 0pened to get back the weighted samples, to analyze their energy content after eight month storage. At the same time, moisture content, ash content, elementary analyses and heating value were measured. Whole trees and chunks have the lowest energy losses if compared with chips. On the other side, transport and following treatments, more difficult for the whole plants, will have an impact on the economy and energy balance of tile productive chain. Both chips and chunks can constitute, in appropriate plants, the final form of fuel, while whole plants must always be processed.