Forests out of balance: The impacts of drought-induced tree mortality on carbon and water cycling

• Applicant: Professorin Dr. Nadine Katrin Rühr
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems ; Forestry
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 286857303

Climate change is increasing the severity and frequency of drought events. Particularly detrimental to trees and forests are prolonged drought periods alongside co-occurring heatwaves. These so-called hot drought events have been observed to trigger tree mortality in many regions world-wide, including Central Europe. Alongside climate change, atmospheric CO2 concentrations are increasing, which may potentially mitigate tree physiological responses to drought events. Here, models can help to tackle the complexity of multiple environmental change, but current model developments lack critical interactions between tree hydraulic conductivity, photosynthesis, tissue senescence and tree mortality. Therefore, we want to enhance a process-based model with a novel state-of-the-art hydraulic description for several tree species that will be linked to other critical plant physiological processes. This will allow us to address how an increased frequency of drought events will alter tree mortality rates and forest carbon uptake under future atmospheric conditions. For parametrization and evaluation across scales, a wealth of data will be used reaching from own experimental results of leaf gas-exchange to tree mortality data from remote sensing studies and forest monitoring networks. The main aim of the project is to assess the carbon sink potential of European forest stands under potential future, more extreme climate conditions.

• DFG Programme: Independent Junior Research Groups