Both "Binsey Poplars" and "To Autumn" have as a theme the transience of nature. In his poem, Hopkins bemoans the loss of his "aspens dear" that have been felled by "hack and rack." He rues the cruelty of those who come in and "hew" the trees so that people who come along afterwards cannot appreciate and enjoy the "sweet especial rural scene." Likewise, Keats extols the beauty of Autumn, "Season of mists and mellow fruitfulness" that
bend(s) with apples the mossed cottage-trees,/And fill(s) all fruit with ripeness to the core....
However, the sense of progression of time is in Keats's poem whereas time seems momentary in that of Hopkins, a single time in which he bemoans the loss of his dear aspens. Also, the tenderness of tone that Hopkins has is not evident in "To Autumn." While Hopkins in apostrophe adresses his "aspens dear," Keats personifies autumn in his second stanza as a gleaner--not particularly a person with whom he would be intimate as Hopkins seems with the aspens. This gleaner "watchest the last oozings hours by hours," and thus ends the fruitful life of the trees and vines. As such there is, then, the suggestion of the end of life as there is more dramatically in "Binsley Poplars." Nevertheless, both poems are sensitive to man's imprint upon nature as the tree-cutters and the gleaners both remove beauty from trees.
In his "To Autumn," Keats reflects upon this season as an ending; he bemoans the loss of spring, the burgeoning of beauty. Instead, autumn has "barred clouds [that] bloom the soft-dying day." With autumn, there is the suggestion of death as winter approaches. With the helving of the aspens, there is clearly death.
Both Hopkins lament and Keats's reflective description contain beautiful imagery. Hopkins describes the poplars as having "airy cages" that
swam or sank/On meadow and river and wind-wandering/weed-winding bank.
Keats describes Autumn as a "Season of mists and ...fruitfulness" containing "plump...hazel shell/With a sweet kernel." Along with imagery, Keats personifies Autuma as
sitting careless on a granary floor,/Thy hair soft-lifted by the winnowing wind...Drowsed with the fume of poppies
Both poets employ alliteration, as well; Hopkins uses the w sound frequently as does Keats in his "winnowing wind."