Hydraulic efficiency and drought response of Douglas-fir, Norway spruce and European beech
PhD Student
Sharath PaligiResearch Outline
The increased frequency and intensity of drought events over the last decades has resulted in direct drought-induced mortality and in higher susceptibility of trees to pathogens across central Europe. In this context, it is important to understand the physiological mechanisms that underly water uptake and drought resistance of trees and stands in relation to its site characteristics and species composition to be able to predict changes in forest structure and productivity.During the first phase of the project, several plant ecophysiological measurements were conducted in the pure stands of Douglas-fir, Norway spruce and European beech by Katja Schumann. In the second phase of the project we extend the study to mixed stands. An outdoor drought experiment with three-four year-old saplings of the three above mentioned species are being conducted under a mobile roof in large pots with sandy soil to examine the combined effect of drought and nitrogen addition on plant vitality and growth. Three soil moisture and two nitrogen treatments are established in a block design for all five stand types (single-species and multispecies pots). Plant ecophysiological measurements that give insights into plant water status variation, stomatal regulation, plant growth responses and the drought response strategies of the plants will be conducted continuously during summer 2021. Further, sap flow sensors are installed to understand water consumption and stand level transpiration in pure stands of beech, Douglas-fir, Norway spruce and mixed stands of beech and Douglas-fir.
The current study will give insights into the stomatal control mechanisms, drought response and drought tolerance strategies of the three above mentioned silviculturally important tree species in Germany.