Assessing impacts of climatic change on forests in the Alps

This paper presents a method to project quantitatively the possible impacts of climatic change on mountain forests at high temporal (annual cycle), spatial, and qualitative resolution. It allows linkage from global scenarios simulated by climate models through local climatic scenarios to stand-specific forest models. The method was applied to four representative sites in the Alps using the CCC-GCMII climate model, a statistical procedure to downscale GCM-output to the regional scale, and the forest patch model FORCLIM. Sharply contrasting forest responses were observed within short distances under the same 2xCO(2) scenario of radiative forcing. While some forest simulations produced only small changes in tree species composition, others produced major changes even to the point of a complete disappearance of the forest. In some cases new species assemblages emerged without any analogue under present conditions. The results suggest that some mountain forests are sensitive to a 2xCO(2) global change, and that human assistance may be required to help forests to adapt. The proposed method made good use of existing data, integrated current understanding, and appears sufficiently flexible and general to assess impacts of climatic change on any mid to high latitude forests in accordance with IPCC guidelines.