Adaptive genetic variation of Norway spruce, silver fir and beech

Climate change is likely to stress forests on many sites. We investigate whether the genetic variation of forest trees enables them to adapt to climate change. We focus on the most frequent species in Swiss forests, Norway spruce, silver fir and European beech.

The methodological approach is as follows: Autochthonous populations should be adapted to the local climate. This shows in seedling traits, e.g., their flushing date in spring and growth characteristics. If seedlings of many populations are planted at the same site, differences in these traits become apparent and can be partly explained by the climate at seed origin with transfer functions. From these transfer functions, the risk of mal-adaptation of a provenance to a different climate can be estimated as the proportion of those seedlings that deviate in several traits from seedlings which are optimally adapted (Beaulieu et al 2004, St Clair & Howe 2007).

In fall 2009, seed of 85 to 90 autochthonous Swiss spruce and fir populations was collected from 3 trees each. The spruce and fir plants are being grown in a nursery since spring 2010. Beech has been collected in fall 2011, and sown afterwards. The seedling experiment is scheduled to start in spring 2012 at 2 sites, in Birmensdorf and Matzendorf. The experimental design contains, for each tree species, 2 sites and 16 replicates. Each replicate contains 240 to 270 plants, one from each mother tree. The seedling trait assessment is planned for 2013 to 2016. In 2015, half of the replicates will receive a combined drought and warmth treatment, using rain shields. The reaction of the seedlings will be assessed in 2015 and 2016.