"The Relative Role of Climate and Herbivory in Driving Treeline Dynamics along a Latitudinal Gradient, 2020" is based on 2 projects: "Effects of changing climate on the alpine tree line and mountain forest carbon pools along 1500 km n-s and elevation gradients "TREELINE"" and "Changing forest area and forest productivity - climatic and human causes, effects, monitoring options, and climate mitigation potential "FORESTPOTENTIAL"". Global studies show a trend of expanding forests into the boreal-alpine ecotone, which are important in Norway. Climate predictions for Norway indicate future changes with a potential for rapid growth in existing forests and dispersion to areas without tree growth. In order to preserve the bio-diversity and fulfill international obligations to reduce greenhouse gas emission, it is important to understand the changes in the boreal-alpine zone will influence the vegetation and potential for carbon sequestration. Grazing has historically been an important factor that has influenced the boreal-alpine ecotones. One of the main goals of FORESTPOTENTIAL was to analyse how the forest in areas near alpine zones can change in the near future. In order to run analyses connected to this, in 2018 and in 36 unique locations, data was collected concerning the establishment, growth, and mortality of pioneer trees in the ecotone between forests and mountains along an 1100 km latitude gradient. At the same time, data on the vegetation on the same localities was collected, and by using a drone, pictures were taken and spectral information registered. The same locations were also previously measured (in 2008 and 2012), funded by the NFR through a research project within the NORKLIMA-programme. In the previous measurements, data were also collected with airborne advanced remote sensing as an uninterrupted transect from the southernmost to the northernmost site - a total of 1,500 km by airline. The data set therefore provides a unique opportunity to follow the dynamics of the tree line over time. Related to each site, we also have information on pasture pressure for a period of more than 50 years, as well as historical climate data over the same period. Based on this, we will also be able to distinguish the contributions of anthropogenic and climatic factors on the tree line dynamic
