Seven trees have been cut down near the Buchenwald memorial to commemorate the victims of the Nazi concentration camp near Weimar.
It is not yet clear who is responsible for the crime.
The trees were dedicated to the children killed in Buchenwald and six named prisoners, as the spokesman for the memorial, Rikola-Gunnar Lüttgenau, announced on Wednesday.
"We are appalled by the targeted attack on the commemoration," wrote the Buchenwald and Mittelbau-Dora Memorials Foundation on Twitter.
Lüttgenau said there had always been damage to commemorative plaques or information signs and daubed swastikas at the memorial in the past.
According to him, the memorial trees that have now been cut down stood on the route of the former Buchenwald railway, which the National Socialists used to take people from all over Europe to the concentration camp.
It is a little outside of the actual memorial site.
It was not the first destruction of trees at this point, said the spokesman.
Planting had to be replaced a few years ago.
Note on ash graves scratched
In addition, it was discovered on Wednesday that unknown persons had scratched a signpost in the memorial to the ash graves in which the Nazis dumped the charred bodies from the crematorium between 1944 and 1945.
The National Socialists deported 280,000 people to the Buchenwald concentration camp.
About 56,000 of them were murdered or died from starvation, disease and medical experiments.
On April 11, 1945, US troops liberated the camp.
Thousands of prisoners had previously died on so-called death marches.