Native American use of fire in ecosystems


Prior to European colonization of the Americas, indigenous peoples used controlled burns to modify the landscape. These controlled fires were part of the environmental cycles and maintenance of wildlife habitats that sustained the people's cultures and economies. What was initially perceived by colonists as "untouched, pristine" wilderness in North America, was actually the cumulative result of these occasional, managed fires creating an intentional mosaic of grasslands and forests across North America, sustained and managed by the original Peoples of the landbase.
Radical disruption of Indigenous burning practices occurred with European colonization and forced relocation of those who had historically maintained the landscape. Some colonists understood the traditional use and potential benefits of low intensity, broadcast burns, while others feared and suppressed them. In the 1880s, impacts of colonization had devastated indigenous populations, and fire exclusion became more widespread; by the early 20th century fire suppression had become official U.S. federal policy. Understanding pre-colonization land management, and the traditional knowledge held by the Indigenous peoples who practiced it, provides an important basis for current re-engagement with the landscape and is critical to correctly interpreting the ecological basis for vegetation distribution.

Human-shaped landscape

Authors such as William Henry Hudson, Longfellow, Francis Parkman, and Thoreau contributed to the widespread myth that pre-Columbian North America was a pristine, natural wilderness, "a world of barely perceptible human disturbance.” At the time of these writings, however, enormous tracts of land had already been allowed to succeed to climax due to the reduction in anthropogenic fires after the genocide of Native peoples from epidemics of diseases introduced by Europeans in the 16th century, forced relocation, and warfare. Prior to the arrival of Europeans, Native Americans had played a major role in determining the diversity of their ecosystems.
The most significant type of environmental change brought about by Precolumbian human activity was the modification of vegetation. Vegetation was primarily altered by the clearing of forest and by intentional burning. Natural fires certainly occurred but varied in frequency and strength in different habitats. Anthropogenic fires, for which there is ample documentation, tended to be more frequent but weaker, with a different seasonality than natural fires, and thus had a different type of influence on vegetation. The result of clearing and burning was, in many regions, the conversion of forest to grassland, savanna, scrub, open woodland, and forest with grassy openings.

Fire was used to keep large areas of forest and mountains free of undergrowth for hunting or travel, or to create berry patches.

Grasslands and savannas

When first encountered by Europeans, many ecosystems were the result of repeated fires every one to three years, resulting in the replacement of forests with grassland or savanna, or opening up the forest by removing undergrowth. Terra preta soils, created by slow burning, are found mainly in the Amazon basin, where estimates of the area covered range from 0.1 to 0.3%, or 6,300 to 18,900 km² of low forested Amazonia to 1.0% or more.
There is some argument about the effect of human-caused burning when compared to lightning in western North America. As Emily Russell has pointed out, “There is no strong evidence that Indians purposely burned large areas....The presence of Indians did, however, undoubtedly increase the frequency of fires above the low numbers caused by lightning.” As might be expected, Indian fire use had its greatest impact “in local areas near Indian
habitations.”

Reasons for and Benefits of burning

Reasons given for controlled burns in pre-contact ecosystems are numerous and well thought out. They include:
This has been expanded on greatly in recent research in the text by Charles Mann.

Impacts of European settlement

By the time that European explorers first arrived in North America, millions of acres of "natural" landscapes were already manipulated and maintained for human use. Fires indicated the presence of humans to many European explorers and settlers arriving on ship. In San Pedro Bay in 1542, chaparral fires provided that signal to Juan Rodríguez Cabrillo, and later to others across all of what would be named California.
In the American west, it is estimated that 184,737 hectares burned annually pre-settlement in what is now Oregon and Washington.
By the 17th century, native populations were on the verge of collapse due to the introduction of European diseases and widespread epidemics against which the Indigenous peoples had no immunity. Many colonists adjacent to the hills often either deliberately set wildfires and/or allowed out of control fires to "run free." Also, sheep and cattle owners, as well as shepherds and cowboys, often set the alpine meadows and prairies on fire at the end of the grazing season to burn the dried grasses, reduce brush, and kill young trees, as well as encourage the growth of new grasses for the following summer and fall grazing season. Changes in management regimes had subsequent changes in Native American diets, along with the introduction of alcohol has also had profound negative effects on indigenous communities. As Native people were forced off their traditional landbases or killed, traditional land management practices were abandoned.
By the 19th century, many Indigenous nations had been forced to sign treaties with the federal government and relocate to reservations, which were sometimes hundreds of miles away from their ancestral homelands.
Through the turn of the 20th century, settlers continued to use fire to clear the land of brush and trees in order to make new farm land for crops and new pastures for grazing animals – the North American variation of slash and burn technology – while others deliberately burned to reduce the threat of major fires – the so‑called "light burning" technique. Light burning is also been called "Paiute forestry," a direct but derogatory reference to southwestern tribal burning habits. The ecological impacts of settler fires were vastly different than those of their Native American predecessors. Natural fires also differed in location, seasonality, frequency, and intensity that Indian-set fires.

Altered fire regimes

Removal of indigenous populations and their controlled burning practices have resulted in major ecological changes. Attitudes towards Native American-type burning have shifted in recent times, and many foresters and ecologists are now once again using controlled burns to reduce fuel accumulations, change species composition, and manage vegetation structure and density for healthier forests and rangelands. Some fire researchers and managers argue that adopting more Native American-type burning practices may prove ineffective for a variety of reasons ranging from insufficient data on the effectiveness of Native American burning, to difficulties in agreeing on a "natural" ecological baseline for restoration efforts. Tribal agencies and organisations, now with fewer restrictions placed on them by the colonists, have also resumed their traditional use of fire practices in a modern context by reintroducing fire to fire-adapted ecosystems, on and adjacent to, tribal lands.