FORHYCS

Changes in forest state, structure and distribution – induced by changes in climate or land-use - will also affect ecosystem goods and services of mountain forests. In particular, mountain forests are key in regulating the regional (catchment to Swiss-scale) hydrology via interception, transpiration and soil-water content. Tree processes, in turn, are strongly influenced by hydrology, which affects water supply and status of the trees, nutrient transport, and assimilation, and can lead to drought stress, decreased establishment and growth, increased susceptibility to pests and increased mortality.

In the forest, changing water supply leads to changing species composition, leaf area, biomass, structure, and density, up to forest-diebacks under extreme conditions. Thus, the influences of forests on hydrology and vice versa form a feedback loop, which links the dynamics of both and requires that they are studied and simulated together. Furthermore, both, forests and hydrology are influenced by climate and land-use change.

To provide regional scale assessments of the combined effects of forest and hydrology dynamics, we built on the first implementation of a coupled model developed in an ongoing project, which is based on the forest landscape model TreeMig and the hydrological model PREVAH.

Goals

1. Initialization and optimization of the model
2. Assess the importance of the forest-hydrology feedback at the regional scale
3. Sensitivity tests and further model optimization
4. Apply the new model using various scenarios of land-use and climate change scenarios