Harvesting techniques and logistics of short rotation energy forestry. A descriptive study on harvest and transport systems in Salix production currently used in Sweden

摘要

This report is the result of a three month thesis project carried out at the Swedish Institute of Agricultural Engineering (JTI) in Uppsala, Sweden, on request of the Agricultural Engineering Department of Wageningen Agricultural University (WAU) and the Institute of Agricultural and Environmental Engineering (IMAG-DLO) in Wageningen. The main topic is the description of harvesting techniques and logistics of short rotation energy forestry currently being used in Sweden. Logistics range from the field to the end user. Also the cultivation method, labour, energy balance, management and costs and revenues are emphasized. For harvesting two methods are used: direct chipping and whole stem harvesting. For direct chipping three machines are available in Sweden: the Austoft, the Bender and the Claas Jaguar. So far the Claas is most liable, it has the highest capacity and it delivers good quality chips. Whole stem harvesting is done with the Froebbesta harvester and the Segerslaett Empire 2000. Both machines are not yet operating to full satisfaction and have to be modified. Still the basic techniques the machines are using seem to be successful. After harvest different systems can be used, described in this report: direct chipping with direct container transport to the combustion plant, whole stem harvesting with chipping done at or near the field and container transport by the farmer using a tractor and trailer, and transport of whole stems. In all these systems intermediate storage of chips or stems can be done. Chips can only be stored for a short period, stems can be stored at any location for a longer period. At harvest the moisture content of the wood fuel is 50%. Not all furnaces can take this fuel so it has to be dried first. 32 refs, 17 figs, 19 tabs