What is the importance of the cemetery in the novel, Jack?

The cemetery is where Jack and Della run into each other and have their first real conversation. It is enormous, about three hundred acres, leading Della to comment that “this place is so big, you wonder who all they’re expecting” (13). Jack feels a sense of green in the cemetery, describing that “it had seemed to him sometimes that, however deep it was, the darkness in a leafy place took on a cast, a tincture, of green. The air smelled green, of course, so the shading he thought he saw in the darkness might have been suggested by that wistfulness the breeze brought with it” (18). He sees the people buried in the cemetery as blades of grass. Live people also hide there at night to escape detection, only emerging at sunrise.