Remy, you are absolutely right. I found it in The Collected Poems, vol. I, p. 163. The online version of The New Age is available online here: https://modjourn.org/issue/bdr445815/ On p. 524 the reviewer (who prefers Mr. H.C. Harwood’s “From the Youth of All Nations”) writes, ‘Mr. Tolkien’s “Goblin Feet” patter in rag-time. Mr. G.B. Smith fancies trees moaning “as for remembered sin.”’

Thank you Const.