This paper presents preliminary results of research about the development of a forest ecosystem management decision support system (FEMDSS) in Portugal. Key components of the FEMDSS are characterized. The data model and its technological application is briefly outlined. The structure of the interactive natural resources simulator is described. Focussed issues include a) database interaction; b) linkage to growth and yield models; c) interactive silviculture modeling; d) geographical information system (GIS) integration and e) linkage to management models. A modular approach to trigger ecosystem management model building according to user requirements is presented. Model solving includes traditional optimisation techniques and heuristics. Adequate solution approaches may be selected iteratively by the user. Finally, a solution report is presented.