"decades, even centuries old"?
see also: Amazon rain forest.
I risk insulting your intelligence by elaborating on that. Still, for the sake of debating form, I'll briefly note that it's estimated that more than 50,000 square miles of rain forest (not just in the Amazaon basin) are being lost each year to slash-and-burn clearing. It continues to this day for the same reason: It's cheaper in the short run.