He also loved animals. Stanza thirteen praises the beauty and worthiness of oxen, tortoises, and mockingbirds. He believed all living things were connected. People are linked with the mares, cats, prairie dogs, and other creatures. That line sums it up.
People are a part of nature.
There is a birth, death, and renewal cycle that connects the two. Stanza six is a simple, believable explanation of death. It starts out in a conversation with a child asking what grass is. When we die, we are buried in the ground. We are returned, in a sense, from whence we came.