Within the framework of the future European strategy for soil protection (COM (2002), 179), consideration is given to the safe use, recovery, recycling and disposal of sewage sludge¹ and other biodegradable wastes (biowastes)² , with emphasis on the responsible recycling of organic residuals through land application as part of an overall strategy on the prevention and recycling of wastes (COM (2003) 301). In EU-15, 45 % of total annual production of 7.3 million tonnes of sewage sludge (dry matter) is currently recycled on land, largely in agriculture. Recycling of sludge on forested land is almost nonexistent and is even forbidden in a few European countries such as Germany. Beyond the generally accepted statement that the use of residuals should be prohibited in natural forests, it is also recognised that in the context of more intensively managed forest systems for biomass or wood production, positive effects of sludge and biowaste application can be expected. In France, recent regulations (1998) on sludge utilisation on land allow applications on forested land but only under experimental conditions. In this context, the research community has been asked to develop additional pertinent information on the environmental sustainability, economic viability and social acceptability of such recycling forest systems which policy makers may be able to use. The main questions which have been addressed concern the fate of heavy metals and other potentially toxic elements in forest ecosystems, the effects on ecosystem functioning and on biodiversity, the potential transfer to the food chain, and the social acceptance. Methodologies include in-situ mesocosms studies, dose-response forest experiments and social surveys. A national network representative of organic residuals types, forest soils conditions and tree species has been established in the past four years. Long term monitoring and demonstration sites are essential components of this integrated experimental approach. Initial results, including effects on forest ecosystem functioning (growth, nutrition) and biodiversity, and effects on forest environment (soil, water) are presented for forest plantations receiving low rates of application of municipal or pulpmill sludge