Abstract: Forest trees have tremendous economic and ecological value, as well as unique biological properties of basic scientific interest. The inherent difficulties of experimenting on very large longlived organisms motivates the development of a model research system for forest trees. Populus has several advantages as a model system, including rapid growth, prolific sexual reproduction, ease of cloning, small genome, facile transgenesis, and tight coupling between physiological traits and biomass productivity. The imminent release of the genome sequence is taking Populus genomics one large step further by providing a catalog of all genes and, most importantly, their regulatory environments. A combination of genetics and physiology is being used to understand the detailed mechanisms of forest tree growth and development. This paper summarizes the progress in genomics research of Populus.