Eighty years after the end of World War Two, blasted trees and rubble forests tell a hidden story of wartime bombardment and Nazi terror.

In the early 1950s, Rudolf Schröder, a young gardener, led a group of apprentices through the abandoned plots of bombed houses in post-war Dresden. Their quest: to find tree saplings for planting along the city's streets. Dresden was still ravaged by the firebombing in February 1945 that killed tens of thousands of civilians. But slowly, here and in other cities across Germany, survivors were starting a green recovery.

"We searched the ruins of buildings with gardens for saplings and found lots of them – linden trees, maple, oak. We dug them up, and planted the best ones along the streets," recalls Schröder, who was born in 1933, speaking from his home in Dresden. "It was a hard time, but we were full of hope."

Saplings were hard to find as so many trees in public parks had been destroyed, and had to be replaced with stock from nurseries outside of the bombed city. It was when those nurseries ran out that Schröder and his friends resorted to the abandoned gardens – where many saplings had sprung up as the plots were left untended. There were enough young trees for some to be taken and replanted along the streets to cheer up the public, and others to be left in place, according to Schröder. Today, some of those rubble-sourced street trees planted by Schröder and his team still stand, for example along the Krenkelstraße street in Dresden, he says.

Eighty years after the end of World War Two and the fall of the Nazi regime, many of Germany's urban trees and green spaces still hold such hidden traces of the past. In post-war Berlin, rare plants suddenly thrived in bombed wastelands, and urban forests sprung up in the rubble. Forest also grew over abandoned Jewish graves, as the Jewish families that had tended those graves were deported and murdered in the Holocaust. Some bomb-scarred trees, and post-war rubble forests, have been turned into memorials and nature sanctuaries.

And in some cases, like that of Dresden's botanical garden and the adjacent Großer Garten (Great Garden) park, a lush green area holds a dark story from the intensifying Nazi terror to the war and its aftermath – giving insights into nature's surprising role as a witness and archive of human history, to this day.

"A new ban for Jews, from entering the Great Garden and other parks," wrote Victor Klemperer, a Jewish literary scholar in Dresden, in his secret diary in July 1940. Repeated across parks and botanical gardens all over Germany, the ban was one of many Nazi measures against Jews in the run-up to the Holocaust. Klemperer explained in his diary that the park ban was especially powerful as Jews already had almost nowhere to go in 1940s Germany: the Klemperers and others had been excluded from jobs, universities, schools and libraries, removed from their homes and put into communal housing with other Jews, and placed under a curfew. Having lost their own home and garden, Klemperer and his non-Jewish wife, Eva, bought flowerpots for their balcony to at least have the comfort of some greenery, as they nervously observed the increasing arrests and deportations of their friends and neighbours.

While the fact that Jews were banned from parks and other green spaces during the Nazi era is generally known in Germany, there is relatively little research on the subject. However, garden historian Joachim Wolschke-Bulmahn argues in a book chapter on green spaces and antisemitic persecution in the Nazi era, that the park bans played an important role in the terror. He notes that the bans also show just how actively some ordinary people participated in the persecution. In cities such as Leipzig, Bremen, Berlin and Hannover, non-Jewish Germans denounced Jewish park visitors to Nazi authorities and helped implement the bans, he and others note. Individual cities took the initiative of banning Jews from benches and parks.

"The Nazi dictatorship relied on the voluntary support of many Germans in order to function," Wolschke-Bulmahn writes. He also points out that this aspect of the Nazi era is generally omitted from official histories of these parks.

Two archived letters from Dresden's botanical garden, provided by staff there, illustrate how meticulously the bans were pursued. "It has been observed that Jews are using the botanical garden," a Nazi party official wrote to the garden's director in 1941, demanding that this be........

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