In Sara Teasdale's poem "There Will Come Soft Rains," how does the mood change dramatically?

Sara Teasdale’s poem “There Will Come Soft Rains” describes nature’s lack of response to the sad vestiges of war.

In the first three stanzas, the author creates images of nature during the spring. The mood is light as the reader envisions a gentle drizzle wetting the sweet-smelling earth. The birds fly around freely, the frogs sing their song, and the wild plum trees show off their blossoms. Teasdale paints an idyllic spring image, which sets the initial tone of the poem.

After the reader is lulled by the spring time description, the mood of the poem changes as the poet describes how nature will not care if man is destroyed by war:

And not one will know of the war, not one

Will care at last when it is done.

Not one would mind, neither bird nor tree,

If mankind perished utterly;

The reader is thrust from the beautiful spring image and associated mood to the image of mans’ demise, which dramatically changes the mood of the poem. The light, enjoyable mood changes to sobering thoughts of the aftermath of war.