Future-ready tree species at the dry forest boundary

On the Lötschberg south ramp, a steep south-facing slope in the canton of Valais, partially irrigated forests protect the railway line from natural hazards. Due to climate change, there is growing concern as to whether this forest will be able to perform its protective function in this dry inner-Alpine valley in the future. To identify climatically sustainable tree species, nine native and non-native tree species were planted at three sites in 2012/2013. The results of this afforestation experiment have shown that manna ash, downy oak, Scots pine and Douglas fir are best suited to establishing sustainable stands on these dry sites. To this end, four different management strategies are presented that consider different needs and priorities: continuous irrigation, no irrigation, early years irrigation, and shelterwood regeneration.