Forests balked the expansion of the Inca civilization on the rainy slope of the Andes, and in Central Africa the negro invaded only their edges for his yam fields and plantain groves.

The earliest settlements in ancient Britain were confined to the natural clearings of the chalk downs and oolitic uplands; and here population was chiefly concentrated even at the close of the Roman occupation.

Only gradually, as the valley woodlands were cleared, did the richer soil of the alluvial basins attract men from the high, poor ground where tillage required no preliminary work.

But after four centuries of Roman rule and Roman roads, the clearings along the river valleys were still mere strips of culture mid an encompassing wilderness of woods.

When the Germanic invaders came, they too appropriated the treeless downs and were blocked by the forests.[140] On the other hand, grasslands and savannahs have developed the most mobile people whom we know, steppe hunters like the Sioux Indians and Patagonians.