Thomas Hardy's speaker addresses a group of four people, which includes the speaker. The overall tone is somber and nostalgic. The primary imagery relates to the natural landscape and the passage of time. Summer and winter are contrasted, as are fire and ash. The speaker evokes these contrasts to create a context for their expression of sorrow over loss: one of the group's four members has died since the last time the group had visited this rural locale together.
Hardy uses the landscape both literally and metaphorically. The speaker mentions climbing a hill in winter to arrive at a "forsaken place." This is a spot that the group has actually abandoned, which also stands for a concept or relationship that the speaker has set aside.
The current time of year is winter, indicated by the cold wind. Furthermore, the "winter mire" through which the speaker climbs lies among gray grass. The lack of life symbolized by the wintry scene is also represented by the remnants of the fire. All that is left is a "burnt circle" with the "charred" bits of sticks.
In referring to these sticks as last relics, the speaker may be likening them to themself as they tell the reader that two of the group have gone to the city, and one has died. Thus this sole survivor may be a relic of their happy summer picnic-filled days—standing for careless youth.