POTSDAM, Germany (AP) — The avenues, monuments and gardens of the park surrounding Sanssouci Palace, a vast green oasis in the heart of the German city of Potsdam and a UNESCO world heritage site, look as magnificent as ever.
But a closer look shows that all is not well with the park’s trees, which are increasingly struggling against the effects of climate change. of Climate Change. Among the signs are beeches with thin crowns, large branches that have fallen to the ground and trunks with much of the bark torn off.
“I have been observing this garden for more than 30 years and I see very serious changes,” says Sven Kerschek, former head gardener for part of the park. “Since 2017 or 2018, we’ve had a very, very serious increase in tree and shrub death; and not just dying, the health of the trees is changing.”
The region experienced a particularly hot and dry summer in 2018, followed by several more years with little rain. The comparatively rainy summers of last year and this year did not offset its effects.
Heat and lack of rain are not the only problems, says Kerschek: “Climate change is more complex.” Well-watered trees on the banks of streams and lakes also show signs of stress. Intense and constant sunlight, lack of atmospheric moisture, storms, increased fungal infections, and the spread of insect species that did not previously occur in the area are among other factors that play a role.
From 2002 to 2015, the park lost between 18 and 87 trees every year. The number has not dropped below 100 since then; it reached 315 in 2020 before falling slightly.
The Prussian Palaces and Gardens Foundation, which oversees Sanssouci Park and many other sites in Berlin and the neighboring state of Brandenburg, is telling the story of trees’ fight against climate change in an outdoor exhibition this summer titled “Regeneration.” At points throughout the park, visitors can see examples of problems and ideas on how they can be solved.
“Maybe the exhibition will help highlight that we have these problems here; that extreme examples of climate change are already visible not only where people live in river valleys and experience flooding, but also in the idyllic Sanssouci Park,” says Katrin Schröder, garden curator at the foundation.
Visitors are pointed out trees that suffer from “sunburn,” with dry, peeling bark, making them vulnerable to fungi and animals. They can see that groundwater has declined drastically in recent years, making life difficult, in particular, for older trees. But there are also more encouraging examples, “survival artists” who defied the odds.
These trees give gardeners reason to hope. Kerschek, who helped design the exhibit, says he wants to “try to continue working with the genetic material we have here in the garden.”
The oldest trees in Sanssouci Park are around 300 years old. The hope is that older, more robust trees that have already experienced climate change will be in a better position to adapt – and that, even if they don’t look particularly healthy, they can pass on that ability in their seeds. One idea is to collect these seeds and grow young trees in a special nursery that reflects the park’s harsh conditions, Kerschek says.
Sanssouci Palace itself was the summer residence of the Prussian King Frederick II, better known as Frederick the Great. It was completed in 1747 with opulent vineyard terraces, a royal retreat with a name that translates from French as “carefree.”
The garden was later expanded substantially, turning into a 19th-century landscape park covering almost 300 hectares (740 acres) and measuring more than 2 kilometers (1 1/4 miles) from east to west. It has around 60 gardeners and has been on the UNESCO World Heritage List since 1990.
While nearly all of the park’s native tree species have struggled with the effects of climate change, the solution is not to switch to exotic species.
Schröder notes that Potsdam still has a Central European climate with sometimes long and very late frosts, so “we can’t do anything here with Mediterranean vegetation.”
But one approach might be to look at whether it’s possible to use varieties of lime, oak, beech or other trees from areas like southeast Europe, which have very hot summers but also late frosts, she says – as long as they look like the trees. . already in Sanssouci.
“We don’t want to change the park in such a way that it has a completely different mix of trees,” says Schröder.
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AP video journalist Pietro De Cristofaro contributed to this report.
