Since 2008 INBO started with the selection and breeding of poplar and willow short rotation coppice purpose, based on the many years of long-term distribution program for tree-forming willows and poplars. A large collection of willow and poplar clones involved in this screening. The selection and distribution program is aimed, in addition to classical breeding criteria such as disease resistance, good rooting ability and rapid growth, soil plasticity, adequacy to link the climate and energy content with each other. This research has as its objective the further optimization of the selection and breeding program by research on physical and calorimetric properties of various selected INBO poplar and willow clones, and this under a variety of growth conditions. The output of this project will be a set of criteria for the selection of INBO poplar and willow clones with superior physical and caloric properties.