I have done a fair amount of teaching in fields and forest. I take people out to show them things, they may have never seen before. I watch them as we walk along. And it is surprising how often folks break off branches that are in their way. Or grab a hand full of leaves and strip them from a tree. Or maybe just bend some tall grass over as their hands trail at their sides. They mostly don't seem to do those things maliciously. Most of the time they don't seem to give it a thought at all.
So, often, we'll stop, and I'll ask them if they would like someone walking by them and just casually rip out a hand full of their hair? They usually reply, that very rarely would they like that. I ask them if they would like being kicked, or have firewood broken against their side, or nails pounded into themselves so someone could build a treehouse. No, mostly not.
Then, maybe we'll sit down and I'll talk with them about the Woods. There is so much to learn, if you just become still. If you watch. Or Listen. There is so much going on around you, that you entirely miss as you bumble along talking loudly, staring at the ground so to be sure of your next step, being impolite to trees and grass by pinching and pulling them. Listen, and you'll hear the birds talk with each other. Maybe feel a slight wind as deer pass by. Or learn about bending with the storm. Or standing tall and strong when others might want you to fall.
The world, all the world, wants to talk with you. It wants to carry you and help you and teach you and learn from you and so much more. But you need to pay attention.
So to the question of "Do trees feel pain?" For me, I don't think so, not like we do. I'm quite certain they feel loss. Are aware of abuse. Are most especially knowing that there passes another uncaring, thoughtless being. I don't believe there is a pain like animals feel pain, or thoughts as we form thoughts. But there is certainly a knowing of thoughtlessness. And awareness of intent. And maybe even a sort of glow that comes of connection and care. The sharing of life in all life's forms and ways.