This is not actually about nature it’s meaning nothing good can stay. In the outsiders this poem is used. When Johnny dies he says stay gold to Ponyboy meaning stay good.
I think this might help you figure out the theme, hope this helps
Answer: A showing statistics that prove soccer is a safer sport than lacrosse
Explanation: I got it right on edge
The primary theme of A Day of Wandering is that nature is intrinsically good and it has a positive impact on us. We should learn to appreciate nature and interact with it because it will not only help us in our spiritual lives but also our social lives.