Insights about past forest dynamics as a tool for present and future forest management in Switzerland

Mountain forest ecosystems in central Europe are a product of millennia of land use and climate change, and this historical legacy shapes their vulnerability to projected climate change and related disturbance regimes (e.g. fire, wind throw, insect outbreaks). The transitional and highly dynamic state of present-day forests raises questions about the use of modern ecological observations and modeling approaches to predict their response to future climate change. We draw on records from the different subregions (northern, central and southern Alps and their forelands) in and around the Swiss Alps, which has one of the longest evidence of human land-use in Europe, to illustrate the importance of paleoecological information for guiding forest management and conservation strategies. The records suggest that past land use had different impacts on the abundance and distribution of woody species, depending on their ecology and economic value. Some taxas were disadvantaged by intensified burning and browsing (e.g. Abies alba, Ulmus, Tilia, Fraxinus, Pinus cembra and the evergreen Ilex aquifolium and Hedera helix); others were selected for food and fiber (e.g. Castanea sativa, Juglans regia) or increased in abundance as consequence of their utility (charcoal, acorns, litter and other products) or resistance to disturbance (e.g. Picea abies, Fagus sylvatica, Pinus sylvestris, and deciduous Quercus). Another group of trees increased in distribution as an indirect result of human-caused disturbance (e.g. Betula, Alnus viridis, Juniperus, and Pinus mugo). Knowledge of past species distribution, abundance and responses under a wide range of climate, land use and disturbance conditions is critical for setting silvicultural priorities to maintain healthy forests in the future.