Where It All Goes Down
The setting ranges far and wide in "The Force…" It's kind of like the poem is happening everywhere at once: it's springtime, it's winter, we're in the garden, at sea, in the mountains, at a hanging (gross), and in a graveyard. This revolving setting helps to give the poem its whirlwind, dramatic, universal feel.
That most of the imagery in "The Force…" is outdoors-y also reinforces the poem's focus on the connections between time's effects on nature and time's effects on human life. Under the awesome power of time, everything is charged and everything dies out. In fact: "in time" may be the broadest, but also the more appropriate, way to describe our setting.