PINE (Predicting Impacts on Natural Ecotones) will investigate the potential impacts of key land-use management decisions on the European tree-line ecotones under different climatic change scenarios. The focus is on identifying critical thresholds of change, some of which may be irreversible. The aim is to inform decision makers of the consequences of their actions in terms of sustainable development, landscape change and biodiversity. The first step will be to assess the decision-makers’ and stakeholders’ perceptions of environmental change and risk. We will then go on to produce a spatially explicit, dynamic forest succession model (TreeMig) tuned specifically to tree-line ecotones. The model parameters are defined using variables which initiate, control and terminate tree growth. These are derived from cambium dynamics and an innovative multi-proxy approach in which the proxies used are tree ring width, density, stable carbon isotope ratios, height increment, needle production and pollen deposition. Data will be collected from a range of tree-line tree species at sites in Sweden, Finland, Austria, Italy and Slovenia. The model will be evaluated using the past response of tree line plant communities to climatic change under varying management regimes and then used to predict changes in the tree-line ecotones in response to climatic change under different land-use change scenarios.