Pre-conference field trip Stillberg treeline experiment

On 12 September 2025, we offer a scientific fieldtrip to visit the long-term treeline experiment Stillberg, near Davos in the Swiss Alps. In 1975, 92000 seedlings of Larix decidua, Pinus uncinata, and Pinus cembra were planted along an elevational gradient at and above the current treeline ecotone (2075-2230m a.s.l.). Survival, growth and health status of these trees has since been monitored, and microsite features recorded. While variation in microsite conditions and snow fungi drove mortality and growth patterns during the first two decades, atmospheric conditions and neighbour interactions have become more important as the trees have grown taller. Starting in 2001, seedling establishment and tree growth limitation at treeline were investigated through several additional experiments (FACE experiment crossed with soil warming, nutrient addition, seed addition). These revealed mixed responses amongst plant species and interactions with belowground processes. Over the years, Stillberg has also become a testing ground for new technologies in forest management, such as the use of remote sensing techniques, and a prime location for scientific outreach. Recently, new questions have begun to arise about competition and facilitation occurring between trees near the treeline, and about suitable management strategies to adapt high-elevation forests to future environmental conditions without compromising the multiple ecosystem services they provide. The field trip offers an opportunity to see and discuss current issues in treeline research, complementing the treeline Focus Session and Workshop at IMC.