Potsdam – The summer? In forests and parks rather boring, a lot of uniform green. The winter? Dark, bare branches of the deciduous trees against a pale sky – more interesting. The spring? Again and again a small miracle, this restart of nature. What about autumn? Is the most beautiful of all seasons – high season for hikers and walkers who enjoy the color of the leaves.
On this October morning, the sky over Potsdam hangs so low that not even clouds can be seen. Everything is still gray over the Sanssouci Park. But everyone who enters through the “green grid” looks around in amazement and slows down.
An avenue with around 200 chestnuts leads into the park. The crowns of the trees are mostly green, but already nicely interspersed with yellow and brown. On the floor there is a carpet of rust-brown leaves with chestnuts in between.
Berliner Zeitung / Jens Blankennagel
Chestnuts in Sanssouci.
The leaves are curled, these old trees are infested with the leaf miner. The moths love the warmth, they immigrated about 20 years ago, coming from the Balkans, because the temperatures rose in this country too. And they keep doing it. How does climate change affect all the other park trees?
Michael Rohde knows the answer. His office is in a house at the end of Kastanienallee. He is a trained tree nursery gardener and studied landscape architect. And since 2004 horticultural director of the Prussian Palaces and Gardens Foundation. Rohde, 59 years old, is the master of 15 parks, over 80,000 trees and almost 180 employees. The heart of the foundation are those large parks that have been declared a World Heritage Site by Unesco, such as Sanssouci, Babelsberg and Neuer Garten – as masterpieces of garden art.
From the office window, Rohde can look across the park to Sanssouci Palace. A bust of the garden architect Peter Joseph Lenné stands on a cupboard. He once designed the park, he lived in the house across the street. “You can’t do more than UNESCO World Heritage,” says Rohde. He shows a poll. German citizens were asked which parks they know: 23 percent named Sanssouci first, followed by the Herrenhausen Gardens in Hanover with 17 and the English Garden in Munich with 16 percent.
Gerd Engelsmann
Garden director Michael Rohde in Sanssouci Park.
Rohde explains why landscape gardens are still so popular today. They came into fashion from 1720, before the baroque gardens of the castles dominated. In them, the beds were laid out in clear geometric shapes, the hedges cut extremely precisely. Everything was symmetrical, correct, clean – and a bit bland. “The aim behind it was: We as humans rule nature,” says Rohde. But with the English landscape gardens, the view changed: The mathematically strict forms fell away, everything became freer and wilder. “Now nature should no longer be subjected. It served as a great model, and the architects designed gardens as idealized imitations of nature. “
Why do we think the parks are beautiful?
Out to the park. Rohde points to a hedge by the side of the road, a bench in front of it and two trees in front of it. They can interfere with the view of the people sitting there, says Rohde. “But they give the ensemble – this overall picture – a depth like in a classic painting.”
The fact that people find parks like Sanssouci to be beautiful is no coincidence, but rather the intention of the artists who created them: landscape architects who used to be called garden artists. At that time they created the so-called “princely green” at the castles, today their descendants create the “civic green” in the city parks.
The basic idea of a park sounds simple: a flat piece of land that the architects structure with paths and hills, with streams and ponds. They have flowers planted, but mostly trees, bushes and hedges. There are also elements such as benches, fountains, bridges, small buildings, artificial grottos, sculptures, and stairs.
A landscape architect combines various elements into one picture. But it’s not just about a single picture. The idea of movement, of strolling, is decisive for the effect of a park: the stroll becomes a walk through a gallery. And a good park is a sequence of many landscapes. They are listed in Sanssouci. “The park is a living, dynamically changing cultural monument,” says Rohde. “We are the conservators and restorers who want to preserve this splendor.”
We stroll on, hear a chainsaw howl and then meet Sven Hannemann. Born in Kleinmachnow, he is a landscape architect and is the park manager responsible for the northern part of Sanssouci. “We have to keep removing dry branches from tree tops or cutting down entire trees,” he says. Nearby, in a meadow, the arborist Erik Zab is standing next to a tall elm. His saw continues to howl, he cuts a branch as thick as an arm. In the treetop, water has collected somewhere, says Hannemann. It had rot, part of the crown had crashed to the ground. Zab cuts the branches.
Gerd Engelsmann
Erik Zab saws up the fallen branches of the treetop.
There is a fight for every tree on the monument. And if he does die, a similar tree will be planted in the same place so that the total work of art is preserved.
But the losses are increasing. “When I started here 20 years ago, the trees that had to be felled every year fit on a piece of paper,” says Hannemann. “It’s a folder now. At that time ten trees, now up to 150 trees – because of climate change. ”The experts used to check once a year whether the trees were suffering, now they do this up to three times.
No gentle rain, but extreme weather
Hannemann explains that in the past 500 liters of rain per square meter per year were common here. Then came three years of drought. “In 2018 we only had 350 liters.” And there were many days with more than 40 degrees of heat. In addition, the rain no longer falls as leisurely land rain, but often as torrential rain. Weather extremes are remembered. “On June 12, 2018, 90 liters fell in one day,” says Hannemann. “That was almost a third of the annual amount.” Because the soil had dried out, it was unable to absorb all the water. It just drained away, didn’t help the trees.
The World Heritage parks are now becoming “laboratories for posterity,” reports Rohde, the director. You are part of a two million euro research project at the Fraunhofer Institute. “Model-based exploration of the methods that can be used to preserve the parks in the long term.” How can water be kept in the landscape? Which tree species can cope better with heat or new pests? All city parks could later benefit from this knowledge.
“The damage to the trees is enormous,” says Hannemann, the park manager. Before he shows it, he stops at an inconspicuous intersection. He wants to explain the ingenuity of the earlier landscape architects, wants to show how they painted their pictures of nature.
The first picture are the paths of the crossroads. “They are not at right angles to each other. This creates tension. ”Shortly after the intersection, a path forks. “That creates additional tension,” says Hannemann and asks where we want to go. When we choose one way and thus the second picture, he asks why. And explains another trick by the horticulturist: The path leads gently downhill in one sweep and disappears behind trees. “Tension again: we want to know what’s there,” he says. “The paths are the silent guides through the parks.”
Eight pictures in 50 steps
The first steps lead through the third landscape picture, three gnarled oaks on the right and five plane trees on the left. The number of trees in a group is always odd – that too is an element of tension. And on top of that, the trees are not at the same distance, just like in nature.
After twenty paces the shadow of the trees ends. The fourth picture on the right: a wide line of sight, 400 meters the view goes over a meadow with beeches and oaks. The image is dominated by an autumn chestnut. The fifth picture on the left. A large conifer next to the path, next to it a dying hornbeam. “They don’t like it,” says Hannemann. “Dead trees are a popular element for picturesque landscapes.”
Berliner Zeitung / Jens Blankennagel
The autumn in simply beautifully colorful.
After ten steps, the sixth picture: again the light-shadow trick, now the path leads through a gate made of beech trees. Behind it it is brighter again and in the seventh picture the gaze falls on a gentle hill with poplars, ash trees and a cherry in yellow. Now the gaze is directed towards the front, on the last picture: Again the end of the curved path is hidden behind trees.
Eight very different landscapes in just 50 steps. Garden art in perfection. But this perfection is in jeopardy. We walk through the wet grass to a group of eleven beeches. Hannemann goes to one of them and points to the bark. It is usually as smooth as concrete, there are many cracks to be seen here. “The sun shines on the trunk from the south. The heat is now so intense that the trees get sunburned. ”The bark cracks. Hannemann is working on a crack and peeling off a large piece of the trunk. He points to the tiny holes everywhere – drilling sites, beetles have taken advantage of the weakness of the tree. Hannemann points up. The crown is bare and mushrooms have settled at the foot of the tree.
The domino effect
The tree has been standing since Lenné’s time. “Without the extreme weather of recent times, he could easily have lived 100 years.” And that’s not all. He points to a tree four meters away. The bark is flawless and the foliage is bright green. At least still. “It was in the shadows for 160 years, now it’s in the front row,” says Rohde. “He’s not used to full sun.” He’s getting sunburn and could die. A domino effect.
The results of the three drought years are bitter. “Twelve percent of the trees are badly damaged or dead,” says Rohde. “Up to 50 percent are damaged.” When the trees that have grown for decades are gone, it is not only their beauty that disappears. They are also no longer used as small climate factories because they no longer absorb carbon dioxide and produce oxygen. The trees in Potsdam’s Unesco parks have bound 175,000 tons of carbon dioxide in the course of their life.
Gerd Engelsmann
The bark of the beech tree is actually as smooth as concrete, but here you can see cracks and tiny holes made by insects.
He looks along a long line of sight, at the end of which a few ash trees are leafy yellow. “Of the 50,000 animal and plant species that are native to Germany, around 10,000 are found in Potsdam’s Unesco World Heritage,” says Rohde, the director. “With our old trees, we are not only a museum of nature, but also a gene pool.” The parks are important. “This is where beauty shows, this is where art shows, this is where nature shows – and the constant warning: Do not overexploit nature.”
Perhaps the most beautiful garden image in this park can currently be seen at the Italian-style Villa Illaire. Wonderful autumn colors shine behind the garden wall. The small wrought iron gate is open, behind it a round fountain – and in the meadow in front of the pond a cinnamon tree. The colors range from soft green to bright yellow and strong orange to deep dark red.
Perhaps the tree will soon lose all of its colorful splendor. But there are still 26,000 trees in this park, despite all unreasonable expectations. Sanssouci is a seemingly endless gallery of landscape paintings. And then another picture is the most beautiful.
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