No, you got the point of the article wrong.
It was *more* trees that sucked more CO2 out of the atmosphere, that the people advancing this theory say could be linked to the decreased CO2 in the ice in Antarctica, that suggests the drop in temperatures during the Little Ice Age may have had a human origin.
Columbus didn’t cut down NO trees.
You are right. I would think that it would take the killing of millions of Native Americans to cause such a reforestation and the colonists made great efforts to clear land themselves. I am confused.