Alfred Joyce Kilmer (December 6, 1886 – July 30, 1918) was an American writer and poet mainly remembered for a short poem titled "Trees" (1913), which was published in the collection Trees and Other Poems in 1914. Though a prolific poet whose works celebrated the common beauty of the natural world as well as his Roman Catholic religious faith, Kilmer was also a journalist, literary critic, lecturer, and editor. At the time of his deployment to Europe during World War I, Kilmer was considered the leading American Roman Catholic poet and lecturer of his generation, whom critics often compared to British contemporaries G. K. Chesterton (1874–1936) and Hilaire Belloc (1870–1953).^: p.27 He enlisted in the New York National Guard and was deployed to France with the 69th Infantry Regiment (the famous "Fighting 69th") in 1917. He was killed by a sniper's bullet at the Second Battle of the Marne in 1918 at the age of 31. He was married to Aline Murray, also an accomplished poet and author, with whom he had five children.

While most of his works are largely unknown today, a select few of his poems remain popular and are published frequently in anthologies. Several critics—including both Kilmer's contemporaries and modern scholars—have dismissed Kilmer's work as being too simple and overly sentimental, and suggested that his style was far too traditional, even archaic. Many writers, including notably Ogden Nash, have parodied Kilmer's work and style—as attested by the many imitations of "Trees".