But he says crops must be replanted to adapt to equipment, at a cost of thousands of dollars an acre, and farmers don't want to uproot productive trees.
At a point in human history when natural predations should be less of a reason to flee one's home ground--increasingly we have the means to overcome droughts or infestations, and global warming (if true) isn't yet a reason to uproot--millions are heading to crowded cities or across deserts or oceans to reach more promising lands.