Humans were burning off the forests and prairies every couple of years in the Americas before the arrival of the Europeans. In North eastern N AM part of the reason was to keep the forest floor clear for buffalo of which there was a large non plains population then. They burned the prairies as an aid to better hunting as game proliferated. In the Amazon they were keeping the forest clear for travel and for better hunting.
I saw somewhere a theory that blamed the European medieval warm period on eastern North American forest burns.