Thus in the winter stands the lonely tree,
Nor knows what birds have vanished one by one,
Yet knows its boughs more silent than before:
I cannot say what loves have come and gone,
I only know that summer sang in me
A little while, that in me sings no more.

Edna St. Vincent Millay (1892–1950) American poet

Sonnet 43 “What lips my lips have kissed, and where, and why,” ll. 9ff. (1920), The Harp-Weaver and Other Poems (1923)
    (Source)

Originally published in Vanity Fair (1920-11).