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Extreme-Adapt: Tolerance and adaptation of tree species to extreme climate events


Extreme climate events such as severe droughts, heat waves and late spring frosts are rare but exert a paramount role in shaping tree species distributions. The frequency of such ECEs is expected to increase with climate warming, threatening the sustainability of temperate forests.

In this project we aimed:

  1. to analyze all tree-ring width series available in Switzerland for five dominant European tree species in order to compare species sensitivity to extreme drought and late frost;
  2. to test genetic differentiation in resistance and resilience to drought in different populations of silver fir (from different regions of Switzerland and different countries) planted in two different common gardens in the 1980s.

Tree-ring analysis

The first goal has been achieved. Using tree‐ring width series from 2,844 trees from 104 Swiss sites ranging from 400 to 2,200 m a.s.l. for the period 1930–2016, we found strong disparities in the species resistance and resilience to extreme droughts and spring frosts. Oak, fir, and to a lower extent beech could moderately cope with severe droughts whereas spruce and larch only poorly resist and recover after such events.

The second goal in under progress.