Environment: Climate change poses a threat to southern European beech forests

Climate change may lead to declines in the growth of European beech trees of 20–50% in southerly parts of Europe over the next 70 years, according to a modelling study published this week in Communications Biology. This could lead to increased forest mortality, according to the authors.

Beech is the most common hardwood tree in Europe. Although recent studies suggest that warming may endanger the species, it has been difficult to predict how resilient beech trees may be to future climate change across the entire continent.

Edurne Martinez del Castillo and colleagues calculated changes in beech tree growth since 1955 by analyzing more than 780,000 tree-ring measurements from 5,800 beech trees from 324 sites across Europe. They then used this data to model how climate change may impact beech growth over the next 70 years under two emission scenarios from the Coupled Model Intercomparison Project (CMIP6), SSP1-2.6 and SSP5-8.5. Under these scenarios the volume of carbon dioxide emitted during the 21st century either reaches net zero around 2075, or peaks by 2100, respectively. The researchers found that growth rates had slowed across most of Europe between 1986 and 2016, compared to between 1955 and 1985 and that this decline was strongest in the south, where growth decreased by 20%. However, they also found that growth rates had increased by up to 20% in parts of northern Europe over the same period, including in Denmark, Norway and Sweden. By 2090, the researchers’ models predict potential reductions in beech tree growth of up to 30% in southern regions, and more than 50% if droughts regularly occur. While the researchers project that growth could increase by 25% in the mountainous regions of central Europe, they estimate an overall decrease in beech growth across Europe.

The findings highlight the importance of developing long-term plans to mitigate the effects of rising temperatures on European forests.