What is past and what is present in this poem? Is "After Apple-Picking" narrated from within the orchard, or later at night? Did he really look through a sheet of ice that morning, or did his mind produce this memory on its own. In this poem, Frost is not concerned with the facts of the past so much as the imagination's ability to cherry-pick (er, apple-pick?) the ideas and images that are most resonant, then weave them into strange and confusing quilts of memory. Also, memory is not just a mental phenomenon. His body contains its own, no less essential memories of standing on the ladder and cautiously collecting apples for days on end.
The poem exhibits what psychologist Carl Jung called "archetypal memory." The speaker's past is figured in archetypes of humanity as a whole, rather than of individual memories.
The speaker experience memory with all of his senses, and not merely through mental images. He can still see, smell, hear, and feel things from earlier in the day.