What is the importance of the churchyard in the poem, We Are Seven?

The churchyard, located nextdoor to the girl's cottage, is where the girl’s two dead siblings, Jane and John, are buried, their graves “twelve steps or more” from the cottage door (39). The young girl spends a good amount of time in the churchyard, specifically by her siblings’ grave. Here she knits, sews, sings, and even sometimes eats after the sun has set. The only other defining characteristic of the churchyard that the young girl provides is the tree that grows above Jane and John’s grave.