A walker stops on a windy ridge and tries to listen to an oak by pressing an ear against its trunk. The attempt fails, at least for a human: all the speaker hears is wind. The second stanza turns to the snow, where the wind has done more than smooth over the footprints. It has lifted them up and thrown them around like ashes, which gives the speaker's passing a faint sense of ending or loss.
The last stanza shifts the mood. The woodpecker, unlike the person, seems built to hear whatever an oak can say, and it answers by tapping. The speaker is left outside this exchange, an observer who can only imagine the conversation. The feeling is quiet humility, tinged with a little wistfulness, but also a kind of pleasure in knowing that the tree is being heard by someone. The cold, blustery setting makes that small, rhythmic tapping stand out all the more.