Three years ago in November, Enrique Hernandez set out to gather crisp apples and herbs from the garden beside his home at the Martinelli ranch. With his harvest, he baked a postre de manzana to celebrate the 94th birthday of Leroy Martinelli, a former rancher and dump operator whose property housed the trailer Mr. Hernandez lived in for 26 years.

Mr. Hernandez recalls that day with a smile. “I brought him the apple tart and…