Assessment of the near-surface wind field and wind-induced tree response in complex forested terrain with air pressure measurements (WiCoTrAir)

• Applicants: Professor Dr. Martin Freudiger; Professor Dr. Dirk Schindler
• Subject Area: Forestry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554691021

Wind storms are critical for the disturbance dynamics of European forest ecosystems, being the most significant natural hazard over the past 70 years. They cause substantial timber damage and affect forest management. In recent decades, storm impact has increased, with six of the seven most damaging storms since 1951 occurring after 1990. This trend is expected to continue, exacerbated by climate change, which will likely intensify wind disturbances, affecting forest productivity, structure, composition, and ecosystem services. Understanding and mitigating storm damage in non-flat forested terrain is challenging due to the complexity of airflow. There is a significant knowledge gap regarding the correlation between storm damage and severe airflow, which is essential for developing effective mitigation measures. Accurate assessment of potentially destructive airflow characteristics in complex terrain requires high-resolution spatial information. The project "Assessment of the Near-Surface Wind Field and Wind-Induced Tree Response in Complex Forested Terrain with Air Pressure Measurements (WiCoTrAir)" aims to address these challenges by improving the understanding of local airflow characteristics and wind-induced tree response in complex terrain. It proposes using air pressure fluctuations on the forest floor as a proxy for above-canopy wind speed and direction, facilitating simpler, area-wide, and more cost-effective wind measurements without extensive infrastructure. The project is based on five hypotheses: 1. Air pressure fluctuations on the forest floor can approximate above-canopy wind speed and direction in complex terrain. 2. Air pressure fluctuations can be statistically related to wind speed and direction fields over a large area. 3. These statistical relationships can generalize small-scale airflow patterns over forested terrain. 4. Validated airflow model outputs can serve as predictors for air pressure fluctuation models. 5. Air pressure fluctuations can approximate effective wind loading on trees in complex terrain. The project has two objectives: 1. To understand the causes and dynamics of air pressure fluctuations on the forest floor in com-plex terrain, enhancing the generalization of statistical relationships between air pressure fluctuations and above-canopy wind conditions. 2. To establish air pressure fluctuations as a proxy for wind load approximations, enabling cost-effective and distributed wind impact assessments. Achieving these objectives will introduce a novel airflow measurement approach particularly suited for forests, improve the understanding of airflow patterns in complex terrain and wind-tree inter-actions, and help mitigate storm damage to forests. Better assessments and predictions of wind-induced tree responses in particularly exposed parts of the landscape will support forest management and conservation efforts, ultimately reducing economic and ecological losses from severe storms.

• DFG Programme: Research Grants