Nancey Murphy explains the shift from hylomorphism to atomism in these words:
"In a world composed of atoms, sensation must result from the impinging of atoms on the sensory membranes, and then from coded information conveyed to the brain and thence to the mind. Ideas in the mind are no longer identical with forms inherent in things, but mere representations produced by a complicated process of transmission, encoding, and decoding. Thus arises modern skepticism with regard to sense perception" (Bodies and Souls, Or Spirited Bodies?, 47).
My comment: On the modern scientific view of the world, which rejects hylomorphism, treeness could be interpreted as a purely natural category: there is no need to invoke Platonic or Aristotelian Forms/forms. Chemically speaking, water is H2O and salt is NaCl. But "saltness" in the Platonic or Aristotelian sense does not exist; neither does waterness. So a natural kind like cathood can be interpreted as a biological class without being understood in terms of ontological structures, abstractions or formal quiddities. Nevertheless, Platonism and Aristotelian hylomorphism continue to subsist, despite the fact that both theories posit the existence of transcendent and absolute Forms/forms.