Thanks for the link, @TheBrandyPath.
There's a reason The Salt Path isn't included in that essay, and I think it's because it's simply not sophisticated enough as a piece of writing. (I've not read the Donaldson book, but have read quite a lot of Kathleen Jamie's essays, which are excellent, and The Outrun.)
I think TSP doesn't reflect on itself as nature writing, or think about what 'nature' might actually be, or how you might right about it without distorting it to be some kind of resource for you, or a reflection of your concerns, and how the human and non-human relate.
The author quotes someone else (can't find the quotation now) as saying
“[t]he real danger is that nature writing becomes a literature of consolation that distracts us from the truth of our fallen countryside, or—just as bad—that it becomes a space for us to talk to ourselves about ourselves, with nature relegated to the background as an attractive green wash”
I think this is pretty much what TSP does -- nature is an uninterrogated, consoling greenwash, an alternative to the glumwashing of SW's relationship with almost all the people she meets. She not only appropriates nature, she instrumentalises it. She never seems to ask herself what nature is, or how it relates to humans or human culture.
That essay references a Kathleen Jamie essay about her mother's death, in which KJ, grieving, acknowledges that this is a natural event, nature taking its course, but struggles to accept this, even as she also examines specimens in a pathology lab, as she waits for her mother to die. After the funeral she goes for a walk and says that nature had gone back to its usual place, fields and trees etc, because it's too difficult for most of us to recognise that we, cancer, bacteria, decaying etc are just as much 'nature' as birds or trees. That we are also animals subject to natural processes is a knowledge that's hard to keep uppermost in our minds.
That's not a question that even occurs to SW as she constructs nature as a form of 'cure' for what is going wrong in Moth's body (which is, of course, 'nature', too).
(ETA. Sorry, had to cut out a chunk at the start because of an accidental strike-through which wouldn't let me correct it. I just said that there are a couple of errors in the essay, understandably as the author seems to be Turkish and at a Turkish university and may not have much knowledge of the UK.)