Autumn trees the colour of bleeding. They pour their bulk away into bright drifts until all the red is drained out of them. They skeletise themselves. And then it is winter, when the whole titanic world collides with its iceberg, scraping white down its flank and starting its slow subsidance into the deep cold. The snail-trail of frost everywhere. The sky bone. The ground pulped and rolled to fresh paper. The black tree given half a layer of Hiroshima-white skin.
It's the transition from leaf-fall to snow-fall. A solid tree dissolving itself into myriad rustling droplets; a fluid rain chilling itself into solid flakes. It's all in the interchange.