According to Scripture, human life began in a garden. But as punishment for their disobedience, Adam and Eve were expelled from the garden. Their posterity is born in exile. And because they were banished, the lost access to the tree of life. They lost the opportunity for immortality.
In Christian tradition, human life ends in a garden. Cemeteries are typically designed and landscaped to resemble park-like gardens. Gardens for the dead.
The symbolic justification for cemeteries is that the dead are buried in the hope of resurrection. At the return of Christ, cemeteries will come alive as the dead in Christ arise.
So the story comes full circle from garden to garden, life, death, and life restored.