Researchers at WSL are studying how Scots pine trees use stored carbon when water is scarce. The project uses radiocarbon techniques to track nonstructural carbohydrates, the carbon reserves trees build through photosynthesis and draw on during drought. Fieldwork is based at the Pfynwald irrigation experiment in southern Switzerland, which includes control, irrigation, and irrigation-stop plots with different water histories. The key question is whether trees with different water histories store and remobilize carbon in different ways. Because atmospheric radiocarbon levels spiked after nuclear weapons testing in the 1950s and 1960s and have declined since, the team can date the carbon held in tree tissues and estimate how quickly those pools turn over. This research matters for understanding forest resilience under drier conditions and for improving estimates of how much carbon forests actually store and release. The project runs from 2026 to 2027 and is funded by the Max Planck Society.
