Congratulations to Simon and Salome for successfully completing their Master's theses and passing their exams! Both theses addressed unresolved questions in tree water relations.

Simon asked to what extent water stored in the trunks of trees contributes to tree transpiration during a drought event. Working at the SCCII research site he showed that 5 to 30 % of the water transpired by temperate trees in a massive drought event originates from internal storage. This is much more than originally anticipated and illustrates the importance of internal water pools for the drought resistance of temperate tree species. Simon’s work was co-supervised by Richard Peters, now at TUM, Germany.

Salome was interested in the genetic variability and phenotypic plasticity of root water uptake depth of different provenances of temperate tree species. For her experiment she used the IPA provenience trial. She found that different provenances of a species show little genetic variability and no adaptation to dry environments with respect to root water uptake depth. However, her data also showed that most species, irrespective of provenance, have a surprisingly high phenotypic plasticity in their root water uptake depth, where individuals growing in dryer environments obtain their water from deeper soil layers than individuals growing in wet environments. This study shows that temperate tree species have at least some capacity to adjust to a drier climate.