Although I don’t think trees feel, I share your feelings about trees, Simon.
And whether or not they are feeling, plants are certainly living; and treating them like inert materials feels wanton.
Not to mention the dependence on them of all life — sentient and insentient.
Life is a product of evolution — Dawkins’s “Blind Watchmaker” — who is blind not just in the sense of lacking foresight and design, but in lacking moral sense (or any sense).
Evolution is merciless, psychopathic. Life feeds on itself, literally.
And although no one knows what the causal function of sentience is (the very query has been dubbed “the hard problem.” it is indisputable that sentience evolved, hence it must have conferred adaptive advantages.
The advent of sentience was also the advent of suffering.
But the advent also of compassion, at least in some sentient species — chiefly, I think, the mammals and birds and other species that did not just split in order to reproduce, like microbes, or lay and leave countless eggs, like turtles, but spawned only a few helpless (“altricial”) young that had to be cared for to survive. Thus was empathy born — and that “mind-reading” ability that is perhaps the most acute in our own species, paradoxically the most monstrous as well as the most merciful of them all.
So it’s a complex problem on which you are embarking, Simon, in pleading for mercy for trees. Not the “hard problem,” but a heart-rending one, coupled as it is with the fate of all living creatures, suffering or not.