Vita Sackville-West loved Virginia Woolf and admired her as a literary genius. On the other hand, Virginia loved Vita who was a "real woman" and who gave her maternal protection, but she did not like Vita's poetry so much. Orlando is Vita's biography but Woolf did not glorify her wholeheartedly.
Orlando starts writing a long poem "The Oak Tree" when he is 16 years old in the 16th century, and she completes it when she is 34 years old in the 19th century. The poem changes as the hero( ine ) grows older, and when it is completed, it contains the whole history of English literature.
Woolf thought literature should aim for anonymity, and it was anonymous when people began to sing in the medieaval wood. The audience felt sympathy with the poet, and sometimes the audience were also poets. But as time passed, the poet and the reader were separated from each other. The wood is the symbol of the state in which people sang and listened to anonymous songs. The sole oak tree which stands on top of the hill in Orlando's park is the remnant of the wood and contains the history of England. "The Oak Tree" is a poem on the oak tree, and it represents Virginia Woolf's ideal poem.
Vita, however, did not aim for anonymity, but wrote poems for fame, thought Woolf. So at the end of the novel she made Vita quit writing poems and turned her into a maternal figure. Orlando is "the longest and most charming love letter" for Vita, and at the same time it is the criticism of Vita.