As a Naturalist, Thomas Hardy employs nature to convey both mood for his works and to convey the Naturalistic indifference of the universe. For instance, his poem entitled "Neutral Tones" he and his love stand by a pond on a winter day, a pond "edged with grayish leaves," that reflects the tone of this poem. This dismal tone underscores the remembrances of the speaker about his former love as their relationship ended: "The smile on your mouth was the deadest thing." With the sun described as "as thou chidden of God" and the "starving sod," nature conveys the dismal mood of the speaker.
In his poem "The Darkling Thrush," Hardy writes that
The land's sharp features seemed to be
The Century's corpse outleant,
His crypt the coudy canopy,
The wind his death-lament.
But, just when the speaker believes that nature shares his mood, a darkling thrush appears and sings
His happy good-night air
Some blessed Hope, whereof he knew
And I was unaware.
So, it really is an indifferent universe that, in its caprice that the speaker does not understand, has a cheerful song.