Swiss experiment targets forest drought, a driver of climate change

Climate change and droughts are transforming forests around the world and reducing their ability to absorb CO2. Which tree species are suitable for the climate of the future? A unique experiment is seeking answers in a Swiss forest. Global warming presents trees with a vital dilemma. "They have to decide whether to risk dying of thirst or starvation," says Markus Schaub of the Federal Research Institute for Forest, Snow and Landscape (WSL) in Birmensdorf, near Zurich. At the root of this crucial choice is not only the lack of water in the soil due to increasingly frequent and intense droughts. There is also a phenomenon that has been little researched in connection with climate change, but which scientists believe plays a significant role in the rapid and widespread decline of forests on all continents: the "water thirst" of the air (or atmospheric drought). As temperatures rise, the air can hold more water as vapour. The air becomes "thirsty", so to speak, and draws more moisture ...