What is this poem about? (Summarize the poem -- is it a narrative poem? If so, what's the story? Is it a lyric?

This is not a narrative poem, because it does not tell a story. It's almost a riddle, because it doesn't come right out and say what it is. I would say it's more of a lament from the tree's point of view, telling humans to enjoy it while they can because their time on earth is not long.