Keats

'If Poetry comes not as naturally as the leaves to a tree it had better not come at all.' But why leaves? Not bark? Not fruit? A metaphorical halfway house between the idea that poetry is integral to the poet, like a skin, and poetry is a detachable offering by the poet. Unless Keats is getting at the notion that poetry sustains the poet; that one's poems perform a sort of photosynthesis for one's own soul?