We have been working for 20 to develop Populus (aspens and poplars) as a model system for biochemistry, molecular biology and physiology of trees. For the last 15 years we have also we decided to complement these efforts with a project to study genetic and phenotypic variation of the natural population of aspens in Sweden, and have since then developed the tools to do this. This project aims to resequence a population of close to 500 aspens, to assist in, for example, in studies on natural variation, population genetics and GWAS - Genome-Wide Association studies - of many different traits.