Quantifying the impacts of lightning strikes on forest dynamics and carbon storage using a dynamic global vegetation model (FlashForest)

• Applicant: Dr. Andreas Krause
• Subject Area: Forestry ; Physical Geography
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 536753546

Lightning is a significant yet often disregarded disturbance agent in forest ecosystems, with potential implications that are currently underestimated. Recent research in a tropical forest in Panama has revealed that each lightning strike on average results in the death of 3.5 trees and that lightning is responsible for over 40% of the mortality of large trees. Given that lightning activity is expected to increase in a warmer climate, lightning-induced tree mortality will likely impact forest dynamics even more in the future. However, current dynamic global vegetation models do not represent lightning damage to trees. This could lead to major biases in simulated forest structure, composition, carbon storage, and ecosystem services under present-day and future environmental conditions. This project aims to bridge this research gap by implementing lightning-induced tree mortality into the well-established dynamic global vegetation model LPJ-GUESS. I will calculate lightning mortality based on local flash frequency, tree diameters, and tree density, taking into account that mortality per strike is highest for large, closely spaced trees. After successful local evaluation, I will conduct global simulations to gain insights into how lightning shapes forest ecosystems across different regions and to assess the importance of lightning-induced tree mortality relative to other mortality causes. Additionally, I will perform future simulations driven by projections of climate change as well as changes in lightning frequency to investigate the persistence of the forest carbon sink under global environmental changes. Finally, the representation of lightning in LPJ-GUESS will also enable me to investigate its indirect impacts on vegetation by promoting other disturbances such as wildfires, insect outbreaks, or windthrows. The overarching goal of the project is to assess the importance of lightning-induced tree mortality in forest ecosystems and to evaluate the ecological risks and consequences associated with increasing lightning frequency. Ultimately, incorporating lightning mortality into LPJ-GUESS will lead to more reliable simulations of forest carbon storage, thereby providing valuable insights for informed decision-making regarding land-use strategies for climate mitigation, nature conservation, and adaptation.

• DFG Programme: Research Grants