at least in the US, trees are grown as crops, for lumber and paper.
"save the trees" makes about as much sense as "save the corn". Once harvested, the plant in question is replanted, for a future harvest.
they might be farmers, but they're not stupid. they rely on the crops for their family's (or corporation's) long term livelihood.
now, mass deforestation in the amazon may be another story. I don't know enough about that to comment, though. But I will say Brazilians aren't stupid, either. I kinda doubt they are mismanaging their rain forest the way environmentalists try to convince you they are.