Land availability and potential biomass production with poplar and willow short rotation coppices in Germany

Several factors influence land availability for the growth of short rotation coppices (SRC) with fast-growing tree species, including the nationwide availability of agricultural land, economic efficiency, ecological impacts, political boundaries and environmental protection regulations. In this study, we analysed the growing potential of poplar and willow SRC for bioenergy purposes in Germany without negative ecological impacts or land use conflicts. The potential biomass production using SRC on agricultural land in Germany was assessed taking into account ecological, ethical, political and technical restrictions. Using a geographic information system (GIS), digital site maps, climate data and a digital terrain model, the SRC biomass production potential on cropland and grassland was estimated using water supply and mean temperature during the growing season as parameters. From this analysis, a yield model for SRC was developed based on the analysed growth data and site information of 62 short rotation plantations in Germany and France. To assess the technical, ethical and ecological potential of SRC, restrictions in protected areas, technical constraints and competition with food and feed production were investigated. Our results revealed that approximately 18% (2.12Mio.ha) of cropland and 54% (2.5Mio.ha) of grassland in Germany were highly suitable for SRC plantations, providing favourable water supplies and mean temperatures during the growing season. These identified sites produced an average yield of more than 14tons of dry matter per hectare per year. Due to local climate and soil conditions, the federal states in northern and eastern Germany had the highest theoretical SRC potential for agricultural land. After considering all ecological, ethical, political and technical restrictions, as well as future climate predictions, 5.7% (680000ha) of cropland and 33% (1.5Mio.ha) of grassland in Germany were classified as suitable for biomass production with fast-growing tree species in SRC.