This is absurd fantasy for some weird and unclear purpose. The fact is the Great Plains have been too arid to support forestation, in recorded history. Without irrigation and ample groundwaters they would be unpopulated deserts today.
Beyond that, the idea of Indians, without so much as iron tools, chopping down hundreds of thousands of square miles of forest is beyond ridiculous.
I hope you were being facetious and I just missed the humor in the lateness of the hour.
Actually, Indians imported beavers to chop down the forests. Of course, that implies that beavers were the first illegal aliens, doing the work that Indians didn't want to do.
History Channel's been showing a two hour documentary on the Little Ice Age. It confirmed my belief that the actions of mankind have a very limited impact on global warming.
I’m not being facetious and it isn’t absurd. The timetable was lengthy. And yes, given a thousand years, you could deforst a large region, especially if you wasted the trees and fiddled with the envirnoment.