A decision support system for forest biomass exploitation for energy production purposes is presented. In the proposed approach, geographic information system based techniques are integrated with mathematical programming methods to yield a comprehensive system that allows the formalisation of the problem, decision taking, and evaluation of effects. The aim of this work is to assess the possibility of biomass exploitation for both thermal and electric energy production in a given area, while relating this use to an efficient and sustainable management of the forests within the same territory. The decision support system allows for the locating of plants and the computing of their optimal sizing (defining which kind of energy is convenient to produce for the specific area), taking into account several aspects (economic, technical, regulatory, and social) and deciding how to plan biomass collection and harvesting. A case study applied to a small Italian mountain area is presented. (C) 2003 Elsevier Ltd. All rights reserved.