In fact, it was after Mr. Johnson won the high jump that Hitler left the stadium in Berlin, before Mr. Johnson received his medal, even though earlier in the day he had greeted German and Finnish winners. Historians have debated Hitler’s motivations in leaving the stadium early — at the time some close to him said he had a prior appointment — officials with the International Olympic Committee told Hitler that he must either greet all winners or none. For the rest of the games, he chose none.
Back home, Black athletes were also shunned, when President Franklin Roosevelt welcomed only the white athletes to the White House. After the Games, Mr. Johnson worked as a mail carrier and then as a merchant mariner. He died, at age 32 in 1946, after falling ill aboard a ship.
But his tree lived on, cared for by his relatives and, later, a family from Mexico that bought the house in the 1990s. It is one of the few remaining “Olympic Oaks,” as they have come to be called. In Berlin, 129 oak saplings were given out — one for each gold medal — and today there are about two dozen left, according to Mr. Mayer’s and Ms. Anderson’s research, in the United States, Germany, Argentina, Finland, Britain, New Zealand and Switzerland. Some were destroyed after World War II began and the full horrors Naziism became clear, some were tossed into the sea when athletes sailed home, and others were planted and later died.
For Mr. Mayer, Mr. Johnson’s tree has provided artistic inspiration.
Several years ago he came to Los Angeles for a residency at the MAK Center, the California outpost of a Vienna museum, with the idea of creating art from the tree. The result was a multimedia installation that was exhibited in Vienna, Berlin and Poznan, Poland. It incorporated seedlings cloned from acorns collected from the tree, and narration of stories connected to the tree’s history, including interviews with the Mexican family.