As a result of decades of man-made climate change, an increasing number of trees are suffering. So far, the European beech has experienced a decline in growth, primarily in southern Europe. European beech is the most important native forest tree species in Germany, and it is most common in Central Europe. A research team from the University of Göttingen has now demonstrated that the European beech is also suffering from increased drought stress in northern Germany during the summer. This climate stress is more pronounced in warmer locations, where these trees are more densely planted, and on very sandy soils. The findings were published in the journal Global Change Biology.
Climate change is affecting forests around the world, including those in northern Germany. Some of the ways that climate change is impacting these forests include:
- Rising temperatures: Higher temperatures can lead to drought, which can stress and kill trees.
- Changes in precipitation patterns: Drought and extreme weather events such as heavy rainfall or flooding can also affect the health of forests.
- Increased risk of pests and diseases: Warmer temperatures can also lead to the spread of pests and diseases that can damage or kill trees.
- Range shifts: Some tree species may be forced to migrate to cooler areas as the climate warms, while others may be able to adapt and thrive in the changing conditions.
- Forest fires: Drought, extreme weather events, and higher temperatures can all increase the risk of forest fires.
To mitigate the effects of climate change on forests, it is important to reduce greenhouse gas emissions and implement conservation and management strategies that help forests adapt to changing conditions.
We can look back over many decades and reconstruct tree growth in the past. These data were combined with those from climate stations in order to determine the relationship between climate and tree growth.
Dr. Robert Weigel
The researchers chose a wide range of sites in their study, from wet to very dry, because there are very dry beech forests even in northern Germany. The scientists collected numerous wood samples at each of these locations in order to measure the tree rings in the tree trunks.
“We can look back over many decades and reconstruct tree growth in the past,” says Dr. Robert Weigel, a postdoctoral researcher in Plant Ecology and Ecosystem Research at the University of Göttingen. These data were combined with those from climate stations in order to determine the relationship between climate and tree growth.
The investigations revealed that drought and heat in June, the main month of growth for beech trees, are the most important climate factors influencing how much the trunk will grow across all the locations studied, with the negative effects being stronger in drier locations. “Looking back into the past in this way enables us to gain valuable information about the potential future of beech,” states Professor Christoph Leuschner, Head of Plant Ecology and Ecosystems Research, Göttingen University.
“The clear message is: dry locations show the strongest long-term decline in growth, because a lack of water is becoming much more common there,” says Weigel. “These results are a warning that the European beech will also be increasingly affected by drought, not just in southern Europe, but also in many regions here in Germany.”
For the future, therefore, it will be necessary to examine more closely where beech forests will be able to grow in northern Germany and which drought-tolerant tree species will be better able to cope with climate change, taking into account the amount of rainfall, current climate trends and soil conditions.
