Résumé
A computer-based economic model of arable, forestry and silvoarable systems was developed as part of the ‘Silvoarable Agroforestry for Europe’ project. The process of developing the model is described in terms of: the model background and purpose, the systems modelled, the objective of the economic analysis, the viewpoint of the analysis, the spatial and temporal scales, the generation and use of biophysical data, the model platform and interface, and the inputs and outputs. The objectives of the economic analysis are to compare silvoarable, arable and forestry systems at a one-hectare scale, and to determine the feasibility of silvoarable systems at a farm-scale. At a one-hectare scale, a partial budget is used to undertake a discounted cost-benefit analysis. The farm-scale analysis allows for heterogeneous land types, multiple enterprises on each land type, phased planting, and farm fixed costs. The model runs on an annual time step and requires biophysical data. It operates in a commonly available spreadsheet and works in different European language versions of the software. The description of the model and the process of development should be useful for future users and those embarking on their own modelling projects. This research was carried out as part of the SAFE (Silvoarable Agroforestry for Europe) collaborative research project. SAFE is funded by the EU under its Quality of Life programme, contract number QLF5-CT-2001-00560, and the support is gratefully acknowledged.