It's a cool concept for a story, a world where people fully become one with the ecosystem. Sadly it's constrained by page count, with a lot more time you could really flesh this story out.

The First Doctor #19

'The Arboreals' (2015) from The Scientific Secrets of Doctor Who

Just rather middle of the road unfortunately. Perhaps if it was further developed it would be quite an intriguing devolution story, because it certainly has a good set-up and payoff in there, but at a measly nine pages it doesn't really have the breadth of time to stretch its legs and explore the concept in a compelling way for me.