Does your state have legislation forbidding hiring without a green card? If not why not? Call your legislators and ask, stop whining about it and be progressive about it. Costs a hell of a lot less than building a stupid fucking wall. This is where the orange man is failing. He don't care, just thinks a wall will work. NO IT WON"T.There are such things as green cards which permit legal employment. I've never checked into the rules and limitations of the cards, but it is a legal way to work here. I don't know anyone who has an issue with those.
Are green cards a way to begin a legal transition to immigrate to the US? If not, I don't know why it couldn't be.
Most of the tree planers here are Mexican. I don't know if they are legal or not. I assume they are.