The Auschwitz II camp, aka Birkenau, was named after the birch trees that grow there. There are also oak trees growing at Birkenau, near the Krema III gas chamber. There are many varieties of oak trees; you can see photos of the various kinds of oak trees here.
What’s this got to do with anything? Today, I read an article here about a tree planted by Alan Heath seven years ago, from an acorn that he picked up under an oak tree at Birkenau. When I visited Auschwitz-Birkenau, it never occurred to me to pick up an acorn to plant in California. The oak trees at Birkenau can’t compare with the magnificent oak trees in California. The birch trees in California are also more beautiful than those at Birkenau. No one goes to Birkenau just to see the trees.
The photos below show what I believe are oak trees near the ruins of Krema III, one of the two largest crematoria at Birkenau.