Sandburg turns the long, slender branches of a birch tree into dancing girls who have been up all night with the wind and rain. In the early morning, the speaker watches them still swaying against the western sky and wonders about the soft “humming, swishing thing” they seem to sing. That sound is really just wind and rain moving through the branches, but the speaker hears it as a new song learned overnight. The mood is fresh, tender, and alive with early spring. There is a quiet sense of wonder, as if the speaker has caught the tree in a private moment after a long, beautiful night. The poem feels gentle, musical, and a little drowsy, like the calm morning after a storm.
Branches — Summary
The dancing girls here . . . after a long night of it ... The long beautiful night of the wind and rain in April, The long night hanging down from the drooping branches of the top of a birch tree, Swinging, swaying, to the wind for a partner, to the rain for a partner. What is the humming, swishing thing they sing in the morning now? The rain, the wind, the swishing whispers of the long slim curve so little and so dark on the western morning sky . . . these dancing girls here on an April early morning . . . They have had a long cool beautiful night of it with their partners learning this year's song of April.