Currently, forest management models focus predominantly on tree dynamics following interventions, and tend to ignore the plant species found below the trees on the forest floor (the understorey). This is a crucial oversight, as the understorey is the major component of biodiversity, provides vital ecosystem services, and can influence the overall functioning of the forest. As such, there is a need for a user-friendly tool to help predict key understorey plant performance indicators (e.g. biodiversity, share of species of conservation concern) across environmental contexts (e.g. macroclimate space, land-use history) and overstorey tree management (e.g. timber species choice, forest management systems, rotation times). Based on the outcomes and insights from the ERC Consolidator Grant PASTFORWARD we propose to solve the lack of a user-friendly tool for understanding vital understorey dynamics by first creating a prototype web-based Decision Support System (UnderSCORE). Creating this tool will transfer the research output of the ERC PASTFORWARD project into a form that is of direct use for policy makers and forest managers. Such a tool is not currently available but clear legal and societal imperatives (e.g. Natura 2000, European Biodiversity Strategy) require its development, and provide the context for its adoption by potential users. The first stage of this proof-of-concept project is to explore and confirm the understorey output data end users require, the input data they could typically provide, and the type of management interventions that they would typically contemplate. In the second stage, we will use this end user information, in conjunction with the distinctive scientific output of PASTFORWARD, to develop a prototype of the DSS. After the development of a first prototype, the DSS will be evaluated by a panel of end-users and then further optimized in order to guarantee maximal use and impact of UnderSCORE.