blackfoot-valley

Even so, well before the coming of agriculture and livestock raising, man had been altering the land in numerous ways, of which aforementioned extinction of whole species of wildlife was only one. The idea of a “natural landscape” unscathed by man before the industrial age, is a modern conceit. One of the most obvious interventions of man is the setting of fires, not only accidentally, but often deliberately to drive animals such as bison, a practice long carried on by various Indian groups. Fire is an effective selector of vege- tation. By destroying young trees that take many years to mature, fire favors the spread of grasses, since grass renews itself each year, fire or no fire. Of course, natural lightning fires occur too, but where augmented by man-caused fires, grasslands expand at the expense of the forest. The west- ern Great Plains are natural grasslands, but much of the tall-grass prairie land in the Midwest exists where rainfall is sufficient to support forest, and it is believed that burning caused by prehistoric man played perhaps a dominant Albert Bierstedt “ Sketch for the painting The Buffalo Hunt” 47