The development of harvesting systems in woody biomass supply chains

Harvesting systems are an essential component of woody biomass supply chains and are a major cost and source of environmental impacts associated with the delivered biomass. Short rotation woody crops have the potential to supply large amounts of biomass over small areas due to their high yields and short rotation lengths. The development of harvesting systems that can effectively cut and chip high yielding woody crops and produce consistent quality material has been a barrier to the deployment of woody crops. Over the past two decades, efforts have focused on developing systems that are based on forage harvesters, typically used in agricultural operations, fitted with headers specifically designed for the high yield and large stem density found in woody crops. Research and development resulted in dramatic improvements in the performance of these harvesters with effective material capacity exceeding 80 Mgdry/h during the dormant season with good ground conditions. The chips produced are of consistent quality that meet recognized international standards. With the expansion of woody crops across the landscape the period for harvesting has expanded into the growing season and to times of the year when ground conditions are wetter. This has resulted in reductions in effective material capacity by 50% and presents challenges for the year-round supply of biomass to end users. Future research and development work will focus on improving harvester performance in a wider range of conditions while maintaining the quality of the biomass produced.