AFFOREST is a 5th framework project in collaboration with five European partners.The aim of AFFOREST is to elaborate guidelines for afforestation of former agricultural land in north western Europe as to account for a number of environmental impact categories: atmospheric deposition, the leaching of nitrate, groundwater recharge and carbon sequestration.The guidelines will be based on 1)exploitation of existing research data complemented by data to be collected on issues where the present scientific knowledge is insufficient 2)use and development of process-based models and 3)a GIS-based system for scenario-analysis and decision-support (AFFOREST-DSS).The objective of the guidelines and AFFOREST-DSS is to support end-users like landscape planners (local) and policy makers (national/regional) scheming future afforestation project in an environmental sound way. The develop- ment of the DSS and modelling will be done by the KULeuven.