Integration of non-native tree species (NNT) that are considered both useful and invasive is a major challenge for conservationists and forest managers. This is the case for commercially used NNT that spread from managed sites to semi-natural habitats where they can eventually pose ecological risks. Because of their perceived or actual detrimental impacts, some NNT in Europe are classified as invasive following a risk assessment. Yet, risk assessment protocols are often based on small-scale studies with unknown representativeness and uncertain data quality. This is particularly problematic when detrimental impacts of NNT are confined to particular ecosystems while providing valuable ecosystem services elsewhere. Yet, considering the context-dependence of undesired effects in risk assessments would help developing recommendations for where NNT can or cannot be planted to limit associated ecological risks, while delivering ecosystem services. Particularly the design of cost-efficient control strategies for NNT that are already too widespread and abundant for eradication, benefit on the identification of sensitive habitats. We developed a methodological framework for site-specific risk assessment that proposes a step by step guidance resulting in recommendations for responsible management of NNT. The framework is based on a stratified assessment of invasion risks posed by NNT which distinguishes among different ecosystem types or sites and which considers the effectiveness of available management strategies. Keywords: Forest management, invasive alien species, environmental impact, risk assessment, evidence base.
