Why Europe's Trees Are Dying: Climate Change and Seasonal Anomalies Revealed

In a significant study released on July 7, 2026, researchers from the Swiss Federal Institute for Forest, Snow and Landscape Research have uncovered alarming trends regarding tree mortality in Europe, particularly in France. The study indicates that both drought and unusual seasonal weather patterns are contributing to the premature death of trees.

Increasing Tree Mortality Rates in Europe

For the past two decades, signs of tree mortality have become more evident across Europe. The latest findings reveal that the state of forests in some regions has deteriorated compared to the 1980s, a time when air pollution had severely impacted tree health. The study, which analyzed data from the French Forest Inventory spanning from 2015 to 2023, identified patterns linked to tree mortality.

Researchers, including an international team from the French Laboratoire des Sciences du Climat et de l'Environnement and WSL, utilized computer models and machine learning to understand the causes of tree deaths. Their analysis highlighted that deviations from typical seasonal climates significantly affect tree health. Notably, they found that favorable conditions, such as warm, wet springs, can paradoxically increase mortality risk.

The Impact of Seasonal Climate Anomalies

One surprising conclusion from the research is that tall-growing trees, such as the silver fir, experience higher mortality rates following seemingly ideal growing conditions. According to Pascal Schneider, the lead author and Ph.D. student at WSL, “This increases their water demand and makes them more vulnerable as soon as conditions become dry.” Early-season water depletion can lead to drought stress during the summer months.

Moreover, the study indicates that wet springs can facilitate the growth of harmful pathogens, further weakening tree resilience. The findings suggest that it is not merely isolated incidents, like summer droughts, that threaten tree survival but rather a combination of climatic anomalies.

Future Implications for Forest Management

As climate conditions evolve, forest management practices must adapt accordingly. The researchers recommend prioritizing the planting of drought-resistant species, particularly from southern regions. Thinning tree stands may also become essential to ensure adequate water availability for remaining trees, especially after periods of good growth.

With the French Forest Inventory encompassing 500,000 trees across 52 species, the implications of this research extend beyond France, offering insights applicable to other European regions. The findings can inform strategies to enhance forest resilience in the face of ongoing climate change.