The writing I have in mind and sometimes indulge in myself is concerned, not with plants, mountains or birds as items of scientific description, but with experiences of nature that impinge upon our moods and emotions, enrich our imagination and reveries, and shape our sense of how we stand in relation to the environing world. In a broad sense of the term, this kind of writing is an exercise in phenomenology, an attempt to render the significance that birds, plants or whatever have for us.
In the doctrine of the world and humankind as 'will to power and nothing else', Heidegger identified not an antidote to nihilism, but the completion of it. For what can be more destructive of truth and value than the doctrine that these are simply the impositions on the world of human exercises of power?
I'm very sceptical about the prospects for 'big' environmental causes - 'saving the planet', halving the world's population, ending the exploitation of animals, and so on - but a person can ask him- or herself how he or she personally may exercise compassion or humility towards animals, vegetal life and so on.