How does Detering react to the sight of the cherry tree? How does Paul explain Detering’s reaction?

Paul tells a story about Detering. Returning from the front in the morning, the men saw a cherry tree. That night, Detering disappeared and came back with some of the cherry branches. In the middle of the night, Paul heard Detering packing. Detering said he had a cherry orchard at home, and two mornings later, he was gone. A week later the military police caught him, and the men have heard nothing of him since.