I love those skies, thin blue or snowy gray,
Those fields sparse-planted, rendering meagre sheaves;
That spring, briefer than apple-blossom’s breath,
Summer, so much too beautiful to stay,
Swift autumn, like a bonfire of leaves,
And sleepy winter, like the sleep of death. —Elinor Wylie
I can't give you a full answer, but I think you should address the issue that pastoral poetry looks at nature idyllically and that speaking of "briefer than apple-blossom's breath," "to beautiful to stay," and "sleep of death" put the emphasis on how temporary beauty is and, thus, could be overturning the conventions of pastoral poetry by being unflinchingly realistic.