Biomass Production (edcjoensuu): Mapping yields of energy crops in Northern Europe

Willow plantations have long been considered a promising source of biomass for bioenergy in northern Europe. Yet, one essential question remains for investors, planners and policymakers: how much biomass can realistically be produced, and where? It is easy to discuss potential in broad terms, but sound supply planning requires spatially explicit estimates grounded in real production data.

This study used harvesting records from 1,790 commercial willow plantations in Sweden and combined them with climatic variables to estimate productivity across northern Europe. Rather than relying exclusively on experimental plots, the analysis was based on commercial plantations. The resulting estimates therefore reflected biomass yields that can be more realistically harvested and mobilised under operational conditions. The models were extended across Sweden, Norway, Denmark, Finland, Estonia, Latvia, Lithuania, and the Baltic coastal regions of Germany and Poland.

The results revealed strong spatial variation in yield potential. Precipitation during the growing season, together with key temperature variables, explained an important share of this variation. Under high-performance conditions, estimated first-rotation yields exceeded 7 oven-dry tonnes per hectare per year along the Baltic coast of Germany, 6 in Denmark, and 5 along the Baltic coast of Poland. Across much of the remaining study area, estimated yields ranged between 4 and 5 oven-dry tonnes per hectare per year. These findings showed that neither land nor climate provides equal opportunities for willow production, even within broadly similar northern European conditions.

The practical relevance of the study lies precisely in this spatial perspective. Biomass strategies should not be discussed only in terms of total land availability, but also in relation to realistic productivity, regional differences and the climatic limits of the crop. Better yield estimates can improve energy-system planning, reduce overly optimistic supply assumptions, and support more informed decisions on where willow could form a viable component of the renewable energy mix.

Climate, however, did not explain everything. Soil conditions, clone selection and management remained highly important, particularly in the most productive plantations. The maps should therefore not be interpreted as fixed predictions for every field, but as a robust reference for regional planning, comparison and future improvement. For bioeconomy and renewable-energy research, this represented an important step towards more realistic assessments of biomass supply.

Reference
Mola-Yudego, B., Rahlf, J., Astrup, R., & Dimitriou, I. (2016). Spatial yield estimates of fast-growing willow plantations for energy based on climatic variables in northern Europe. GCB Bioenergy, 8, 1093–1105. https://doi.org/10.1111/gcbb.12332