Fire was the most significant tool American Indians possessed for altering the landscape. They burned fields to both clear them and release nutrients into the soil. Hunting often involved driving deer and other animals with fire. Occasional fires also kept the forest floor clear of underbrush, making travel easier. Such burning encouraged the growth of smaller plants that provided browse for deer, thereby helping increase the food supply and number of deer, a key source of food, clothing and raw materials for the Chesapeake peoples. While Smith and his men saw the Chesapeake as unaltered wilderness, its forests and other vegetation had been significantly influenced by the actions of American Indians.