Alarming tree inspection in Schwetzingen: Climate change is taking toll!

Alarming tree inspection in Schwetzingen: Climate change is taking toll!

Climate change is not taking a break in Schwetzingen either. The increasingly frequent periods of heat and drought are putting considerable strain on the approximately 6,000 trees in the castle gardens. According to arborist Hanna Nimmenich, every second tree in this historic area is weakened or already damaged. "In recent years we have noticed a faster loss of trees. That doesn't bring much joy," explains Nimmenich. Regular tree inspections have become more important. These now take place every nine months, which was previously only the case once a year, in order to prevent the tree population from suffering further. The tree inspectors are on duty in the castle gardens every day to identify abnormalities and, if necessary, to carry out a more detailed examination using special equipment such as sound measuring devices.

The situation is alarming. “For many trees, the balance between the plants and harmful fungi has shifted due to the drought,” says Nimmenich. The tinder fungus infestation of horse chestnuts now leads to immediate felling, because the wood infestation becomes noticeable within a short time. And even healthy trees are no longer safe: branch breaks known as “green branch breaks” can unexpectedly occur even in healthy trees. "The cause of this is still unclear. Sometimes dead trees are still safe even with visible damage," continues Nimmenich.

Role of fungi in climate change

The problem is not just limited to trees, as tree death also impacts fungal populations. According to a report on tagesschau.de, drought and global warming are affecting various types of fungi. Some may disappear in nature, while others, such as toxic variants, spread. The mushroom season shifts due to climatic changes, and mushrooms live in close symbiosis with trees, which directly affects their health. Observations from various regions show that spruce trees in particular are severely affected and tree death is also clearly noticeable in Germany.

Equally remarkable is how fungi act as carbon stores. Researchers have found that root fungi store over 35% of annual CO2 emissions from transport. “The potential of fungi to influence the climate is often underestimated,” it continues. There are also some fungal species that specialize in dead wood, such as the giant porling, which benefit from the changed conditions.

The solution: diversification of tree species

One possible way to strengthen tree resilience is to diversify the tree population. “By planting different tree species, we create a better basis for a healthy ecosystem,” recommends Nimmenich. This diversity can help trees become more resistant to heat and disease. The influence of mycorrhizal fungi on the vitality of trees should not be neglected. Studies show that Douglas firs, for example, grow faster when they are connected to multiple fungal partners - a good example of how important the underground exchange between trees and soil fungi is for tree health.

Overall, it is clear that climate change is not only increasing the symptoms of tree death, but is also putting the interaction between trees and fungi to a severe test. It remains to be seen what the challenges of the future will be: Nature often has its own strategies for dealing with stress. It will be exciting to see what impact these developments will have on our forests and the associated ecosystems.