Some parts, copied and translated from the Dutch Wikipedia website BUCHENWALD. The link refers however to another English site about Buchenwald.
The new Lagerkommandant of Buchenwald was Hermann Pister, he took office in January 1942. In that year an arms factory was built, and thousands of Soviet forced laborers came to the camp. Disabled groups were transferred to Dachau, Jews to Auschwitz. It was also decreed that prisoners' hair should be used to make felt and textiles. At the end of 1942 the number of prisoners was 9517, in that year 2,898 were killed in the camp.
In 1943 many prisoners were employed in the arms industry. To this end, sub-camps were built at Erla-Maschinenwerk GmbH in Leipzig, Junkers Flugzeugwerken in Schönebeck and Rautalwerken Wernigerode.
As the Red Army advanced, more and more prisoners from other camps were evacuated to Buchenwald. For example, 4,200 Jews came from Czestochowa, 7,350 from Auschwitz and another 7,800 from Groß-Rosen. Those who arrived alive were dying of exhaustion, cold and hunger. Buchenwald thus became the largest camp. In February 1945 there were 112,000 prisoners, 25,000 of which were women. About a third were Jewish. Conditions were now also getting worse due to overcrowding, dozens of people died every day due to hardship.
Forced labor was maintained to the very end. Sub-camps were only cleared at the last minute; the prisoners who were too weak to walk were shot by SS men. This led to massacres at subcamps in Leipzig, Gardelegen and Ohrdruf.
At the beginning of April 1945, Kommandant Hermann Pister was ordered to evacuate the camp, when there were 47,500 prisoners in the camp. About 28,000 people were sent in death marches towards Dachau, Flossenbürg and Theresienstadt. Thousands of them died of exhaustion or were murdered along the way.