Climate Change Survival: How Swiss Trees Are Receiving Vital Mist Before It’s Too Late

In a Swiss pine forest, researchers are exploring how moisture in the air affects trees’ survival. They’ve set up eighteen tall scaffolding towers in Pfynwald, a region in southern Switzerland. These towers spray water vapor over about 60 Scots pines, which are around 15 meters (49 feet) tall.

This innovative study aims to understand the impacts of dry soil and dry air on a forest ecosystem. Project leader Charlotte Grossiord explains, “We want to figure out how a lack of atmospheric water impacts forests, not just spray them to save them.” The team includes experts from the Swiss Federal Institute for Forest, Snow and Landscape Research and the Swiss Federal Institute of Technology in Lausanne.

The goal is to measure tree dieback—when branches and leaves start to die off. Researcher Giovanni Bortolami notes that this will help predict when similar forests may face threats. They aim to develop better forestry strategies and choose appropriate tree species as Switzerland deals with drier summers. The Swiss environment ministry predicts that by 2060, summer rainfall could drop by 25%, leading to prolonged droughts.

Understanding tree mortality is crucial. Grossiord highlights that trees help indicate carbon dioxide levels in the atmosphere, a major greenhouse gas linked to climate change.

The Pfynwald forest, one of Europe’s largest Scots pine forests, hosts about a thousand trees, each around a century old. Nestled at 615 meters (2,017 feet) above sea level in the Rhone river valley, it experiences some of the hottest, driest conditions in Switzerland, making it a perfect location for this research.

Since 2003, scientists have been investigating tree dieback due to soil dryness. Some forest sections receive irrigation, while others are shielded from rain to study dryness effects. The recent introduction of mist sprays aims to tackle another concern: the increased thirst of air due to climate change.

Warmer air is thirstier than cooler air, a phenomenon known as vapor pressure deficit (VPD). This makes trees lose water more quickly. Bortolami uses an analogy: a glass of water dries up faster in a desert than in a rainforest, which is exactly how trees behave in different humidity levels.

The mist sprays reduce air’s thirst, providing 20-30% more moisture during the day. Researchers monitor trees’ diameter and sap flow—indicators of how stressed they are for water. The study will continue until 2028, and early findings show that dry soil speeds up leaf dieback, which was anticipated.

However, researchers found a surprising twist: dry air slows down foliage dieback. When moisture is low, trees close their pores to conserve water. But this survival mechanism has limits. In Pfynwald, Scots pines are struggling, making way for younger oak trees growing in their place.

As climate challenges mount, monitoring these changes is vital for managing forests and preserving biodiversity. The weather is not just about the rain; it’s about air quality and how trees respond to their changing environment.

For a deeper understanding of climate implications, you can refer to reports from organizations like the Swiss Federal Office for the Environment.



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