For many years it was believed that Native Americans used what they could find in their immediate environment to supplement their diet and lifestyle with little disruption to the surrounding landscape. Today, many scholars disagree that the original inhabitants of the Americas had little impact on the environment. Calling this the myth of the “ecologically invisible” American Indian, critics instead believe that Native Americans altered the land to better suit their needs. Based on archaeological evidence (mainly charcoal deposits and pollen records), in addition to eyewitness accounts by European explorers, many experts now contend that prehistoric people deliberately set fires to accomplish a variety of tasks. Besides using fire to clear large tracts of wooded land for farming (by 1500, millions of acres had been cleared to plant corn, squash, and other domesticated plants), Native Americans also set fires to improve visibility, facilitate travel, and control the habitat of the forest by getting rid of unwanted plants and encouraging the growth of more desirable ones like blackberries and strawberries. Fire also was used to make hunting more productive in two essential ways. First, Native Americans would light fires near a grazing herd to either force them off a nearby cliff to escape the flames or compel them to run towards hunters waiting to kill the animals with their spears. Second, the fires set to keep the land open and grassy also increased the number of bison, elk, and deer in the area, thereby making hunting even easier for the Native Americans.