Motivation:
In Switzerland, temperatures have risen markedly from the end of the 20th century to the beginning of the 21st at more than twice the global average. Climate models project that air temperatures will continue to rise throughout the 21st century. Elevated canopy temperatures intensify evaporation and exacerbate the effects of more frequent and prolonged heat waves, leading to a steady decline in the water available to trees. Although heavy rainfall events are expected to become more common in summer, much of this precipitation will run off the surface rather than infiltrate the soil, limiting its benefit to deeper root systems. As a result, tree canopies are likely to experience increasing thermal and water stress, reducing photosynthetic activity, vitality, and growth. Over time, chronic heat and drought stress may increase tree mortality and drive shifts in vegetation zones. These impacts are expected to be especially pronounced in the inner-alpine dry valleys, such as those found in Valais.
Objectives:
We are seeking a motivated Master’s or SIE project student to process and analyze drone-acquired thermal imagery of forest canopies to uncover relationships between atmospheric and soil drought and leaf temperatures. The student will work on data collected during Summer 2025 in the “VPDrought” experiment located in the Pfyn-Finges Nature Park to investigate how forest canopy temperature varies across different times of the day (diurnally) across the summer season, and how it is modulated by abiotic environment through a controlled factorial experiment manipulating soil and atmospheric moisture in a natural pine (Pinus sylvestris). Trees are sub-divided into plots in which they (1) are left to grow naturally (control), (2) are irrigated at around 2x natural water availability, (3) receive 50% less soil water using rain exclusion shelters, and (4) have reduced atmospheric water demand with the use of fine-spray misters deployed in the canopy. The student will become trained in the use of geographic information system (GIS) software, thermal image analysis software, and R statistical software to create and analyze the data, and gain competence in scientific writing.
Practical details
Start date: Early 2026 (flexible)
Location: EPFL Lausanne, in the offices of PERL
Duration: As required by Master’s program or SIE
Contact:
Dr. Alyssa Kullberg
Office: GR B2 426