Ignition Sources

Considerable debate has occurred among scientists and resource managers across North America and within the MTP specifically regarding the frequency of lightning-caused fires (Russell 1997; Parker and Ruffner 2004). Based on our data, this ignition source was relatively rare in the central North American grasslands (see also Moore 1972). In the MTP, our review found that Native American ignitions greatly outnumbered lightning ignitions, and they should therefore be considered primary for the origin and maintenance of these grasslands (Abrams and Nowacki 2008). Only three lightning-caused ignitions were noted out of 194 fires from 1794 to 1887 (Table 2), and just two out of 569 fires for Minnesota from 1895 to 1904 (Andrews reports 1896-1905). The three lightning-caused fires during the European settlement era of 1794–1887 occurred in Livingston County, Illinois, in September of 1860, and were notably observed by the party of the Prince of Wales while on a hunting trip to the United States (Table 2).

Table 2.

Wildfires attributed to Euro-Americans, 1794 to 1887, in the Midwestern Tallgrass Prairie. Abbreviations: N = North, E = East, S = South, W = West, NW = Northwest, SW = Southwest, SE = Southeast, V. = very, Str. = Strong, G = Gale, PWFL = Powerful, Pr. = Prairie.

Continued.

Continued.

In this episode, rain followed the lightning, but the precipitation was insufficient to extinguish the flames. The fires continued to burn, eventually becoming one and sweeping across a considerable expanse of prairie (Woods 1861; Table 2). There were other mentions of lightning-caused fires, like those in southwestern Illinois by Oliver (1843), but details were not provided. Residents near Bloomington in McLean County, Illinois, associated small circular areas in summer prairie to lightning (Short 1845). Later, Ellet (1853) described blackened patches of prairie vegetation near Chicago during July in 1852 that were considered to be lightning-caused. June and July are characterized by frequent lightning strikes, especially in the northern and central parts of the central North American grasslands (Higgins 1984). Prairie vegetation is usually too moist to burn during summer months when lightning strikes are most frequent. Periodic drought years, such as 1819, 1856, or 1871, could have potentially desiccated vegetation enough to enable lightning ignition and then fire persistence (Clandening 1927; Table 2). The Grand Prairie Natural Division of east-central Illinois, plus much of the prairie regions of Iowa and Minnesota, remained relatively unpopulated until the arrival of railroads in the 1850s (Pooley 1968). Therefore, observations and descriptions of lightning-caused fires on the open, flat prairies would likely be rare within large portions of the MTP due to sparse populations and the obvious absence of observers during these years. However, even when they ignited, such fires seemed rarely to become the landscape-level conflagrations that were especially common during the fall and primarily associated with human ignition.

Figure 2.

Wildland fires by decade within the Midwestern Tallgrass Prairie Region from written accounts (summarized from Table 2).

Figure 3.

Number of wildfire reports (dark line, right axis) and sizes in hectares (bars, left axis) by cause reported by state fire wardens in Minnesota from 1895 to 1904 (data source: Andrews 1896-1905).

One common fire-starting method of Native Americans, as described by Hennepin (1972), involved the use of a cedar (eastern red cedar, Juniperus virginiana L.) plank or fire-board containing numerous small, circular holes that did not completely penetrate the wood. A stick of a harder wood was inserted into a hole and twirled quickly by hand or a small bow until a fine, hot powder was produced (Schoolcraft 1851). This powder was placed on dry grass and gently blown upon, causing flames to develop almost immediately (Pease and Werner 1934). Once started the fire could have been placed on tinder such as grass or punky wood. Other authors suggest Native Americans commonly used iron pyrites and flint to ignite fuels (Hough 1926; Stirling 1955; Williams 2002).

The methods of ignition for fires attributed to Europeans often involved the use of steel, flint rock, and tinder. Tinder included wood shavings, dry grass, birch bark, rotten wood, or even wool. The flint was struck forcefully with the steel to produce a spark. Repeated efforts caused the tinder to smolder or burst into a small flame. The fire maker blew on the tinder, increasing the flame. More tinder was added, and a small fire was soon produced. Many pioneers kept a tinder box at home that included abundant tinder along with pieces of tackcloth, flint, and steel. The introduction of matches made the tinder box obsolete.

Ignition sources changed during the latter part of the nineteenth and early twentieth centuries as commerce, including railroads, increased and agricultural technology advanced. The Minnesota data suggest that burning of stubble, crop residue, and prairie to facilitate plowing became the dominant sources of ignitions (Figure 3). Another prominent source was wood- and coal-burning locomotives (Pettis 1903; Kinney 1917). Residents along the North Missouri Railroad “suffered greatly from prairie and grass fires,” causing them to be “afraid to leave home” during dry seasons (Switzler 1882). In Iowa a locomotive of the Northwestern Line “set the prairie on fire west of Sac City,” and a “large amount of hay was burnt” (Hart 1914). A prairie fire, started by a locomotive near the town of Goose Prairie in Clay County, Minnesota, on 12 October 1895, burned nearly 394 ha (Andrews 1896). The vegetation was as “dry as powder” on 26 October 1895 when a southbound Baltimore and Ohio locomotive started four major fires while traveling the 135 km between Flora and Shawneetown in southeastern Illinois, destroying hay, fences, and several orchards (Anonymous 1895). Another locomotive started a fire in Onstad Township, Minnesota, on 28 September 1898, burning 750 ha of prairie, several homes, a schoolhouse, grain, hay, and numerous fences. The schoolhouse was destroyed when especially strong south winds blew embers a distance of approximately 35 m onto the dry, wooden shingles of the building (Andrews 1899).

Purpose

The purpose of Native American fires seemed to include deer and bison hunting, harassment of Europeans, and vegetation management. Seventeen fires set by Native Americans were for hunting deer or bison (Morrissey 2015; Table 1). Hunting may have taken them great distances from home as stated by Deuel (1958) for the Illinois Territory: “When these savages go hunting, they commonly go out in great numbers, and oftentimes a great many days journey from home.” This travel may have facilitated fire ignition over large expanses. We found evidence for Native American use of a hunting method known as a ring fire, circle fire, or “surround” when pursuing deer (Odocoileus virginianus Zimm.) or bison (Bison bison L.) (Reynolds 1887; Anderson 1901; Hodge 1907-1910; Deuel 1958; Sultzman 1997). The process began in the MTP with the selection of a “fire chief” by the tribal council (McClain and Elzinga 1994; Stewart 2002). This person organized the tribe into three or four groups that went onto the prairie before sunrise to surround the bison. This hunting methodology involved a large number of people from the village. Fire was started on all sides once conditions were suitable. Severe penalties were imposed upon anyone who scared the bison, including destruction of personal property and banishment (Blair 1911).

Data from Native American fires indicate recognition and use of local weather conditions during hunts. One such event describes a party that waited until the sun had dried the grass before setting fire to it during a bison hunt (Blair 1911). Dry grass would ensure faster burning and hotter fires compared to those involving wet grass. Damp grass would also produce much more smoke. In a hunt on the Sandusky Plains of Ohio, Ottawa hunters waited until rain was about to fall before setting fire to the grass, hoping the precipitation would put out the fire so unburned prairie would remain and additional circle hunts for deer could be conducted at later dates. Rain did not develop, and the entire prairie burned, ending their circle hunts for the season (Washburn 1977).

Although hunting was a primary use of fire, it was also used to harass Europeans. Government surveyors in White County, Illinois, in 1804 returned to camp to learn that their wagon and other items had been burned (USGS Field Notes 1804). There was hostility toward surveyors, called “land lookers,” because they were using tools, surveying compasses and chains, that took land away from Native Americans (Ferris 1856). Woods and prairies were burned over a period of several days near the Turkey River in eastern Iowa in an effort by Native Americans to drive white hunters off the land (Murray 1839). A prairie fire in the fall of 1819 in Sangamon County, Illinois, is suspected to be harassment. This fire, driven by a strong west wind, came roaring at a home site, causing the family to work feverishly to save their cabin from the flames. Their cabin was the only one present in the vicinity, making it unlikely for a fire to have originated from other settlers (Selby 1912). Other authors suggest Native Americans used fires to extend hunting seasons, to keep vegetation low near dwellings, for protection from humans and rattlesnakes, the creation of desirable wildlife habitat, and to promote the growth of certain plants (Ruffner 1999; Stewart 2002; Williams 2002; Abrams and Nowacki 2008).

Figure 4.

Causes of grassland fires reported by state fire wardens in Minnesota from 1895 to 1904 (Andrews 1896-1905).

We were unable to determine the exact purpose of most fires attributed to Europeans (36%; Table 2), but in the earlier study period most were likely accidental and attributable to campfires, brush and woods clearing, or locomotives especially in later years, as suggested by the Minnesota data and other authors (Pettis 1903; Kinney 1917; Hough 1926). Similar proportions of fire were caused by burning pastures and field stubble (19–22%), locomotives (12–18%), and burning firebreaks (2–21%; Figure 4). Moore (1972) reported carelessness as a major cause of fires by European settlers during the 1800s in the northeast and central regions of the western plains. Our results provide evidence that the causes of ignitions differed by season and time period across the MTP, while Moore (1972) found that campfires were a primary reason for European fires in the Central Plains.

Even though fires frequently escaped, there was often a purpose to the initial ignition. For example, it was common practice in Illinois during early European settlement to use fire to eliminate prairie thatch to make the breaking of prairie sod easier (Sackett 1842). Fire was also used to burn strips around crops and buildings to reduce danger from uncontrolled prairie fires (Mitchell 1837; Short 1845; Baldwin 1877). It was also an aid used to eliminate thatch to prepare ground for planting of cool-season grasses, like Kentucky bluegrass (Poa pratensis L.) or smooth brome (Bromus inermis Leyss.), which could provide forage, but also serve as fuelbreaks (Mitchell 1837; Gerhard 1857). Fuelbreaks were often constructed using plows, rakes, and backfires to protect buildings and property. Roads also served as fuelbreaks, although that was ancillary to their primary purpose. Other agriculture related tasks, such as burning field stubble or protecting threshing machines, were often mentioned as subsequent causes of wildfires (Figure 3).

Figure 5.

Seasonality of wildland fires during 1794–1887 within the Midwestern Tallgrass Prairie Region (summarized from Table 2).

Farmers were known to burn prairies in May to kill nesting prairie chickens (Tympanuchus cupido L.) because they were eating corn that was left standing in the fields during winter months (Kennicott 1855; Maue 1928; Schorger 1943). Fire was also used in June of 1870 to kill young grasshoppers that were devastating crops in Becker County, Minnesota (Wilcox 1907). In more wooded areas, such as glades and savannas, fire was used to remove underbrush and encourage grasses and forbs for pasturing and grazing animals (Pettis 1903; Russell 1997; Nelson et al. 2008; Considine et al. 2013). No evidence was found in the literature indicating use of circle fires or other hunting methodology during the European settlement period (1794–1887; Table 2). While hunters were often blamed for the origin of fires (Hough 1926), little documentation was found to support this statement. However, rural people clearly organized action groups (Table 2) to protect capital, including crops and outbuildings, so we must assume a strong level of organization for fire containment on the part of the Euro-American settlers during the period 1794–1887 (see Wildfire Legislation below).

Seasons of Occurrence and Indian Summer

Our historical data reflect a strong seasonal relationship across Native and Euro-American periods (Figures 5 and 6). Grasslands worldwide are generally characterized by a season during which the vegetation becomes dry and flammable (Sauer 1950). In the MTP, this time period begins following the first killing frosts of October or early November when gentle breezes, warm temperatures, and clear skies prevail (Curtiss 1852). A mass of Pacific air often dominates the weather during this time producing low humidity and westerly winds (Bryson and Lahey 1958; Huschke 1959). Regularly occurring weather patterns of this nature are known as singularities (Wahl 1952, 1954; Peck 1975). This fairly regular weather pattern was noted as “Indian summer” in eastern states as early as 1788 (often “Second Summer” in modern usage), but this term increased in vernacular use by Europeans in the Midwest during the nineteenth century (Volney 1804; Drake 1815; Foot 1836; Huschke 1959; McClain and Elzinga 1994; Oliver 2005). Lapham (1873), writing about the great fires of 1871, related the tinder dry condition of October to this annual weather pattern, which was manifest in that year by drought conditions and strong southwest winds. Grasses in the time of Indian summer, according to some pioneers, “presented a combustible material surpassed only by kerosene and gunpowder” (Perrin 1882).

Figure 6.

Seasonality of Euro-American grassland fires reported by state fire wardens in Minnesota from 1895 to 1904 (data source: Andrews 1896-1905).

The fall fire season was often characterized by a smoky atmosphere sometimes dense enough to obscure the sun and moon for days or weeks (Faux 1823; Foot 1836; Anonymous 1856; Flower 1882; McMurray et. al. 2007). Andrew Ellicott, while on a journey down the Ohio River from Pittsburgh in October of 1796, encountered 15 days of smoke dense enough to prevent him from seeing the length of the boat, or to the opposite bank (Ellicott 1814). Major Steven Long experienced dense smoke on 15 of the days between 22 September and 8 November 1819 due to burning prairies while stationed at Council Bluffs, Iowa (Thwaites 1904). Welby, in Maryland in November of 1819, described “what in England would be thought a fog,–here they say it is smoke arising from burning barrens and prairies which are yearly at this time set on fire; indeed we have lately passed close enough to woodland on fire to see the flames and to hear the crackling of the timber” (Thwaites 1905). The sun appeared as a giant orange ball on days when the smoke was less dense (Faux 1823; Mitchell 1837; Oliver 1843; Gerhard 1857). Days of this nature were described by John James Audubon, while on the Ohio River at Henderson, Kentucky, on 20 November 1820: “The Indian summer, this extraordinary phenomenon of North America, is now in all of its splendor, the blood rising sun and the constant smoky atmosphere” (Audubon 1999).

In Bond and Montgomery counties, Illinois, “dense smoke arising from the (prairie) fires of Indian summer often enveloped the country in the shades of evening” (Perrin 1882). Smoke created by fires in Edgar County, Illinois, caused people to become lost in the forests in daytime because “it being so dark, owing to the thick smoke, they could not see their way” (Perrin et al. 1879). Lapham (1873), while writing about the great fires of 1871, stated: “A smoky atmosphere in autumn (in the Midwest) has been the common experience every year, and this smokiness has its origin in prairies fires.” Grandma Jane Patton of Piatt County, Illinois, also wrote about smoke from the fires of 1871: “Mr. Patton and I went to Indiana, and came home the first week of October, I think the driest time I ever saw, and fires filled the air so full of smoke that you could not see very far” (Gardner 1908). Pioneers attributed the dense smoke to the burning of prairies by Native Americans, causing them to apply the term “Indian summer” to this season (Wells 1819; Flint 1826; Bell 1830; Foot 1836; Dunlap 1855; Caird 1859; Blanchard 1882).

We found records of 23 fire events attributable to Native Americans during the fall months (September through November). The earliest known ignition was recorded in 1673 in the Illinois Territory and the latest in the fall of 1836 in southwestern Illinois (Table 1). No record of a spring fire (March through May) was identified, but a single summer fire, described as more smoke than flame, was observed by Benton (1957) in Lee County, Illinois, during August of 1833 (Table 1). Fire history studies from the Great Plains demonstrate the use of fire every month except January by Native Americans, with a peak during October and November in the northeast and central regions (Moore (1972). Higgins (1986) found spring and fall to be peak burning seasons for Native Americans in the high plains of the West. Ignitions were still being described by travelers on the western plains for years following the Civil War, enabling the construction of more detailed fire histories for indigenous people compared to the eastern part of the central North American grasslands.

Our data include 140 fires for September through November that were attributed to Europeans. Blackened ground was noted 16 times, documenting fires at earlier dates, including six that were fall fires based upon the date of observation (Table 2). Two of these fires were extensive, burning hundreds of hectares of prairie and forest, including whole counties. This compares with 14 fires started during spring months (Mar–May) during the European settlement period (Table 2 and Figure 6). Baldwin (1877) described use of July fires on unburned prairie as a method of providing fresh grass for grazing, and as a way to eliminate prairie sod. Other prairies burned in the spring because wet weather during the previous fall prevented ignitions (Blane 1824). Increased landscape fragmentation from encroaching railroads and surveyed farm and road boundaries may have prevented fire from spreading into some prairies, making them a potential source of landscape fires during dry spring months.

Spring burning of field stubble and native grassland became increasingly common during European settlement as grasslands were converted to agriculture (Andrews 1896-1905). A total of 157 Minnesota wildland fires were due to burning stubble to facilitate plowing (Figure 4). Containment was always a problem during these times because the implements used—“wet sacks, brooms, branches, and rakes”—were not efficient for fire containment. The most effective firebreak then in use was plowed ground, but strong winds could easily blow embers across these lines into flammable fuel, which was recorded in the Minnesota reports.

Weather

Weather data for fires attributed to Native Americans were generally not available. Only five descriptions contained information on wind conditions (Table 1). It is assumed that dry conditions prevailed during many of these burns, thus allowing Native Americans to complete their hunts as reported in the data. Escaped ring fires would continue to burn once the hunt commenced, spreading throughout the territory and burning through all areas having fuel dry enough to sustain fire, as reported in Ohio (Washburn 1977).

Weather conditions during the European Settlement era were described as “dry” (21 fires), “tinder dry,” “remarkably dry,” or “very dry” (9 fires), and “drought” conditions (11 fires). The weather was “warm” or “very warm” (8 fires), “mild” or “very mild” (2 fires), and “cold” (1 fire; Tables 1 and 2). Prevailing wind directions were from the west (22 fires) and south (16 fires; Figure 7). Three fires were driven by a north wind, and two by east winds. Wind velocity was described as “strong” or “very strong” (30 fires), “gale” force, “stiff gale,” “great velocity,” or “violent” (17 fires), “terrific fury,” “fierce,” or “furious” (8 fires), and “very windy,” “powerful,” or “hurricane force” (4 fires; Table 2). The intensity of the southwest winds during the great fires of 8 October 1871 was described as “powerful enough to force a strong person to the ground” (Lapham 1873).

Frequency and Trends over Time

The earliest known wildfire descriptions for the MTP were written by Jesuit priests and French explorers in the later part of the seventeenth century. Few descriptions were identified for the next 125 y despite the continuous presence of French settlements and hunting parties that routinely searched the landscape for bison, deer, and other fur-bearing animals. The 32 fire events identified for Native Americans are insufficient to establish frequency. However, sources suggest fire hunting was an annual event prior to the introduction of horses (Shea 1852). J.A. Oakwood (1886), a resident of Vermilion County, Illinois, described how Native Americans (the nearby Miami Tribe), “previous to 1834, annually set fire to the tall prairie grass, and burned off the whole face of the country, timber and prairie.” Tribes in Ohio used the plains lying between the Portage and Maumee rivers in the northwestern part of the state “every fall for the ring hunt” (Finley 1859). Fire hunting was continued by some tribes following the arrival of Europeans, but the introduction of firearms, beginning early in the seventeenth century, reduced the need for this use of fire. Schoolcraft (1953) remarked how “these practices (fire hunting) are less common now than formerly, the introduction of firearms among most of the tribes, putting it in the power of almost every individual to kill sufficient for the support of his family.”

Precipitous Native American population declines following contact with Europeans also likely contributed to a reduced use of landscape fire (Thornton 1987; Denevan 1992). Indigenous tribes along the Mississippi River lost scores of individuals to smallpox and other diseases in the 1700s (Le Page du Pratz 1758). Epidemics of smallpox, measles, and other diseases swept the country, sometimes eliminating entire villages (Charlevoix 1761; Thornton 1987; Jones 2004; Morgan 2010). The Illinois Confederacy, formerly a powerful group of at least 11 tribes and more than 10,000 members in 1673, was reduced to only 500 individuals in 1800 (Temple 1958; Sultzman 1997; Morrissey 2015). Henry Brackenridge, while writing about Native Americans in Missouri and neighboring states, described their populations as less than 10% of what they were 30 y earlier (Brackenridge 1814).

Figure 7.

Wind directions for early European settlement ignitions, 1794–1887 (summarized from Tables 1 and 2).

The number of European recorded ignitions increased rapidly after the year 1820, coinciding with the arrival of waves of immigrants (Table 2; Figure 2). Fire records were identified for nearly every year from 1816 until 1904 when they began to diminish due to landscape fragmentation associated with agriculture resulting in the disappearance of large expanses of grassland. This pattern generally corresponds with fire frequency trends documented by tree fire scar data in the Midwest (Guyette et al. 2002; McClain et al. 2010). The years with the greatest number of identified ignitions in the European settlement era were 1819 (11), 1843 and 1855 (7 and 14), 1836 (8), and 1835 and 1871 (9 and 8). Fires were widespread in 1819, being reported from Illinois, Iowa, Indiana, and Maryland. The increase in the number of ignitions may be related to the strong emphasis on agriculture and industry by the European population. These ignitions, as well as those from Minnesota from the years 1895–1905, appear to represent “waves of fire” associated with increasing agricultural intensification here and elsewhere in the MTP (Andrews 1896-1905; Stambaugh et. al. 2018; Figures 2 and 4).

Areal Extent

The unbroken landscape of the Midwest, with its flat to gently rolling topography, presented few barriers capable of stopping wildfires driven by strong winds. A fire in Ohio in 1756 burned a prairie estimated to be over 25,000 ha in size (Washburn 1977). The narrative of Andrew Ellicott, on his journey down the Ohio River from Pittsburgh, Pennsylvania, in 1796, includes almost daily comments on wildland fires for the period 29 October to 16 November 1796 (Ellicott 1814). William Faux (1823), while traveling through southwestern Indiana and southeastern Illinois on 1 November 1819, described prairie and forest fires with sky-reddening blazes, dense smoke, and blackened ground on a journey covering approximately 75 km. In November of 1819, John Woods (1822) traveled north through burning timber for three days on a journey from Shawneetown on the Ohio River to Albion in Edwards County, Illinois, a distance of approximately 90 km. Flint (1826) described thousands of hectares of prairie on fire in the fall of 1825 near St. Louis, Missouri, and Foot (1836) described burning prairies for approximately 60 km in all directions at Fort Winnebago, Wisconsin. Robert Campbell traveled across burnt prairie for several days between 13 and 23 November 1832 along the Red River Valley of North Dakota, a linear distance estimated to exceed 150 km (Sutherland 1926).

A large fire started at 10:00 AM in the fall of 1836 in prairie near the Spoon River in Stark County, Illinois. This fire burned north, driven by a strong south wind, for 160 km, reaching the Rock River where Rockford now stands by 4:00 PM, and blackening thousands of hectares of prairie (Matson 1872). An Illinois fire, in September of 1856, burned through Ford and Iroquois counties before stopping at the Kankakee River, consuming thousands of hectares of grassland (Anonymous 1884a). Prairie fires in Minnesota, likely in the fall of 1856, “licked the country clean for hundreds” of kilometers (Anonymous 1857). Thousands of hectares of burning prairie were described by Brunson (1900), Newhall (1821), Blane (1824), Marsh (1978), Fordham (1906), and Cunynghame (1851) (Table 2). The fires of 1871 were unprecedented in their extent, property damage, and loss of human lives within the midwestern tallgrass prairie. This year included the Chicago and Great Peshtigo, Wisconsin, fires, the latter being the deadliest fire in the history of the United States, which is estimated to have burned 500,000 ha of land, killed an estimated 1500 people, and left thousands more missing, injured, and homeless (Lapham 1873; Pernin 1971).

Fire Effects on Vegetation

One of the earlier descriptions of the effects of fire upon woody vegetation within the MTP was written by James Smith in 1756 in Ohio while a captive of Native Americans. He described the rapid growth of tree sprouts in unburned prairie and their destruction once fire returned (Washburn 1977). Similar observations were made in Illinois by Jones (1838): “The yearly burning consumes all the new trees and shrubs.” Fires in Missouri and Illinois, owing to the severe drought of 1819, burned longer and deeper into the forests, causing great injury to trees (James 1823). Faux (1823), also writing about the fires of 1819, described the sound of falling trees near Princeton, Indiana, as “like the discharge of ordnance.” Hall (1831), also writing about Illinois, stated: “All of the young timber is destroyed by fires.” Hundreds of hectares of forest were destroyed by fire in eastern Illinois (Parker 1836). “The timber is destroyed on the high ground (in southwestern Illinois) where fire can run” (Flagg 1838). These drought-year fires also had profound effects on wetlands, often changing them dramatically. Fires in the fall of 1835, September of 1856, and October of 1871 in Kankakee and Ford counties, Illinois, and Becker County, Minnesota, burned peat in marshes, creating deep holes and making ponds and lakes out of former shallow wetlands. These fires continued to burn long after the arrival of the winter snows, melting snow and producing volumes of steam for months until accumulating moisture finally extinguished them (Anonymous 1884a; Bartlett 1904; Wilcox 1907).

Fire Effects on People

Uncontrolled prairie fires, driven by strong winds, were menaces greatly feared by pioneers. Personal property, including crops, livestock, “snake” or Virginia rail fences, barns and outbuildings, was frequently destroyed. A petition presented to the Illinois Territorial legislature in 1807 by a group of Gallatin County farmers complained of livestock injury and mortality due to prairie fires (Anonymous 1815). Personal injury was rare, but a seven-year-old girl burned to death in Story County, Iowa, on 1 November 1859 after becoming lost in prairie during a fire (Tjernagel 1953). A family of five, also in Story County, Iowa, perished on the open prairie, after encountering a roaring headfire driven by a strong wind (Tjernagel 1953). A young couple and their horse perished in a prairie fire in Kankakee County, Illinois, prior to 1849 (Burroughs 1923). Prairie fires were “unusually disastrous in Iowa” in October of 1872, “destroying a number of houses and a large amount of grain, fences, and other property, and burning two children to death” (Anonymous 1872). In September of 1885 the Dakotas were “fearfully ravaged by prairie fires. Hundreds of farmers [were] burned out, losing houses and crops” (Anonymous 1885). Insurance companies advertised in newspapers, urging farmers to “prepare in time for the fires of fall” (Anonymous 1861). These advertisements often listed damages caused by prairie fires in several states as evidence of the need for insurance.

Early Wildfire Legislation

From the earliest stages, protection from wildfires was highly desired by Europeans in the MTP. In 1785 the French Village of Cahokia in St. Clair County, Illinois, passed an act to control fires: “It shall be prohibited for all hunters and other persons who may be going or coming to set fire to the meadow which may result [in] the burning of the fences and the feed of the cattle.” Those that set fires were responsible for the damages, a fine of 150 livres (value of one livre equal to a pound of silver), and confinement “in irons for eight days” (McDermott 1949). Louis Giroux was indicted at Prairie du Pont (now Dupo, Illinois) in 1794 for setting fire to the commons, causing the loss of fence rails (St. Clair County Circuit Court Case 1794).

The Northwest Territory (comprising Illinois, Indiana, Michigan, Northeastern Minnesota, Ohio, and Wisconsin) legislature passed a law in December of 1799 restricting wildland fire use (Pease 1925). The rapid conversion of the landscape to agriculture, and the increasing number of settlers, buildings, crops, and livestock, made wildland fires increasingly less desirable. Citizens continued to complain, thus promoting more restrictive legislation and penalties. The Illinois and Indiana Territorial Government made the act of burning prairies a misdemeanor in 1807, and persons found guilty were subject to a fine of not less than $5 nor more than $100 (Philbrink 1945). Additional legislation was enacted in Illinois in 1845, making the negligent, careless, intentional, or willful burning of prairies or woods illegal, except for the necessary preservation of personal property once two days' notice was given to neighbors. An open burning period was generally allowed across many MTP states from the first day of March until the last day of November (Brayman 1845; Kinney 1917).

These laws were rarely enforced, resulting in few convictions. A Kane County, Illinois, lawsuit involving Peter Johnson was an exception. His son, John Johnson, set fire to prairie on family property on 15 November 1845, but the fire passed onto a neighbor's land, destroying his house and crops (500 bushels of wheat, 500 bushels of oats, and 15 tons of hay) and 6500 fence rails having a presumed value of $1480 (Kane County, Illinois Circuit Court 1846). Damages were awarded to the plaintiff, but the case was contested, causing it to make its way to the Supreme Court of Illinois, which affirmed the circuit court's ruling, awarding damages to the plaintiff, Newman Barber (Illinois Supreme Court 1849). The Johnson's property was subsequently sold at a sheriff's auction, probably to pay the judgement of the court.

Prairie burning continued, as did damages from fires, but identifying the guilty person(s) was difficult. Some individuals, including John McCarthy and Burge Vermilion, were indicted, jailed, and placed on $100 bond in Shelby County, Illinois, in 1845 and 1851 for the crime of “firing the prairies” (Shelby County, Illinois, Circuit Court 1845, 1851). Likewise, Matthew Herbert, David Ogden, Nelson Case, and John Matlock were indicted in December of 1845 for “firing prairies” in Knox County, Illinois, and subsequently fined $5 each (Chapman 1878). Indictments likely resulted more often when the firing of prairies caused some sort of property damage.

All states enacted wildland fire legislation by the late 1800s following the Chicago and Peshtigo fires of 1871, and the Hinkley, Minnesota, fire of 1894. These laws, depending upon the state, imposed fines ranging from $1 to $1000, jail sentences of up to one year, or both, and resulted in fewer fire starts per decade by the early 1900s (Fernow 1896; Pettis 1903). These acts were considered necessary for the protection of people and property, plus the successful management of forest resources. The end result, in most cases, was greater emphasis on fire suppression. Some states, such as Minnesota, implemented a system of fire wardens, one per township, who were responsible for responding to, containing, and extinguishing wildland fires. Annual reports for this state were compiled by a chief fire warden whose job was to oversee the fire suppression program (cf. Andrews 1896-1905). Elsewhere, localized burning, mostly within forested regions like southern Illinois, continued well into the 1900s, causing State Forester R.B. Miller to regard fire as the most destructive element threatening the forests in this part of the state (Miller 1920).

We found evidence that many early fire laws allowed for “necessary burning” with permits and trained crewmen and fire wardens to provide oversight. Legislation required railroad companies to treat potential fuels within their rights-of-way with either burning or cutting brush and plow lines (Kinney 1917). Until later laws, such as the Weeks Act (1911), required state Forestry Commissions to develop fire control methods, there was no way to extinguish fires driven by a strong wind; they were allowed to burn without regard for the potential for property damage to landowners living far from the fire's origin (Kinney 1917; Bramwell 2012). In general, most fire laws written after 1885 included stiffer penalties for violating burn bans or negligent escapes (Kinney 1917). Obviously, greater attention to rogue fires became a hallmark of the US Forest Service and most conservation agencies after the disastrous conflagrations of 1894, 1897, and 1910.

Effects of Fire Absence

The grasslands of the MTP were essential to the livelihood and survival of Native Americans. Fire was an effective tool in seasonal deer and bison hunts, events that were repeated annually. In contrast, Europeans greatly feared fast-moving fires, causing the application of the terms “trains of desolation” and “messengers of death.” Stopping these threats became a major goal, but it was one that ultimately meant eliminating the MTP, a landscape which once occupied more than 20 million hectares of central North America. The end came quickly through a combination of plowing, fire suppression, overgrazing, and drainage. The loss of grasslands in Minnesota was accelerated by an annual $20,000 legislative appropriation designated for tree planting in prairies, a practice of 25 y duration by 1896 (Andrews 1896). Today Illinois, Indiana, and Wisconsin have lost 99.9% of their prairies while Minnesota and Missouri have lost 99.6% and 99.5%, respectively (Bogue 1963; Smith 1998, 2001).

Prairie wildfires ended in the MTP by the late 1800s due to landscape fragmentation (Guyette et al 2002). Boies (1868) described how “very speedily, the prairie fires went out when the prairies were being crossed here and there by highways, hedges, and dwelling houses.” A rapid growth of trees was noticed on prairie and barren sites early in the nineteenth century following an apparent reduced use of fire by Native Americans (Bourne 1819; Ferris 1856; Dorney 1981). This rapid tree growth was likely initiated by well-developed root systems of trees, known as grubs, which were repeatedly top-killed by fires. Grubs were evident to a Cook County, Illinois, man when he tried to plow his prairie. He found it to be “full of roots of trees which had been prevented from growing by previous annual prairie fires” (Andreas 1884). Edwin James, while writing about forests near St. Louis in 1820, described a “dense growth of oaks and elms since the yearly ravages of fires have been prevented” (Thwaites 1905). Flagg (1838), visiting the same site 16 y later, described “a young forest that was a treeless, shrubless waste” 30 y earlier. A St. Clair County, Illinois, forest, about the year 1855, contained trees large enough to provide timber for a small building, but was reported as prairie 35 y previously (Peck 1975).

The absence of fire resulted in profound changes in forest communities throughout the MTP. Baber's Woods in Edgar County, Illinois, now regarded as an upland forest, was an open savanna community at the time of Euro-settlement characterized by large, open-grown, widely spaced white oaks. Its overstory currently contains an oak cohort whose ages correspond to the cessation of wildland fires in the 1800s (Ebinger and McClain 1991; Parker and Ruffner 2004; Lhotka et al. 2016). A post oak woodland in Hamilton County, Illinois, contains an oak cohort having ages corresponding to a 33 y fire-free interval beginning in 1852 (McClain et. al. 2010). Oak cohorts whose growth coincides with pioneer settlement are also known from Iowa, Indiana, and Wisconsin (Thomson and Hertel 1981; Duvick and Blasing 1983; Apfelbaum and Haney 1991).

Further Observations and Conclusions

We consider the number of fires attributed to Native Americans to be small considering the size of our study area, the length of our study, and the number ignitions reported by similar studies in the western plains (Moore 1972). Diseases, population loss, forced migration, firearms, warfare, the introduction of horses, and widespread cultural destabilization associated with European contact likely contributed to a reduced number of fire hunting events attributed to indigenous people during the late seventeenth, eighteenth, and early nineteenth centuries (Denevan 1992; Sultzman 1997). Localized or occasional use of landscape fire certainly continued, as evidenced by the Potawatomie near the Kaskaskia (Okaw) River in Illinois, the Miami Tribe in eastern Illinois prior to their removal in 1834, and the annual ring fires on the plains between the Portage and Maumee rivers of Ohio (Finley 1859; Williams 1881; Oakwood 1886). However, early nineteenth-century observations by Bourne (1819), James (Thwaites 1905), and Flagg (1838) regarding the rapid woody invasion and conversion of prairie to woodland suggest use of landscape fire by native people within the MTP during that time was functionally nonexistent over a majority of the region (Morgan 2010).

We also believe ignitions are underrepresented for the early Euro-American settlement and agricultural intensification period (Table 2, Figures 3 and 4). Narratives from 1832 to 1894 contain language that suggests only highly threatening fires, events that would create great panic, were recorded. Descriptions of 44 fires describe wind velocities as “strong, furious, violent, hurricane,” or “gale force.” Others report fires as “terrific, raging, awful,” or “threatening” (Tables 1 and 2). Documents were located that mentioned very damaging wildfire events, like those for Gallatin County, Illinois, for the early 1800s, but no information on their size, location, and date of occurrence could be identified (Anonymous 1815). McCulla (1914) refers to numerous undescribed fires in Iowa, a statement supported by Hart (1914): “There is not a county in all western or central Iowa but what can furnish facts for a chapter of prairie fires which would chill one's blood at the terrible recital of havoc from 1855 to 1876.” Years of terror were recorded for the Dakotas in the 1880s and 1890s when powerful winds drove prairie fires, causing great losses and the application of terms like “fearful, destructive beyond precedent, tremendous, immense, raging, great, total, and furious” to these events (Anonymous 1879, 1885, 1887, 1888, 1889, 1890, 1891). No data, including the number of fires, their locations, or their areal extents, were identified for these ignitions. In contrast to powerful wind-driven fires, slow-moving or nonthreatening fires were rarely mentioned in the literature. The author of the history of Becker County, Minnesota, regarded slow-moving fires as a “tame affair,” and residents rarely paid much attention to them (Wilcox 1907).

The 569 grassland fires identified in Minnesota for the 1896–1905 agricultural intensification period represent uncontained ignitions, fires that required the intervention of wardens and their crews. The use of fire to clear thatch from fields to facilitate plowing was widespread, and inadequate preparations were often the cause of an escaped fire. Wardens were required to prepare a report, citing the cause, extent, and damages caused by escaped fires. In contrast, no records exist for ignitions that were contained without incident (Andrews 1896-1905). This 10 y record of a high number of unreported annual grassland fires no doubt characterized other states of the MTP as well.

It is currently a common practice within the MTP to utilize prescribed fire during late winter or early spring prior to the growing season. A primary objective for the selection of this time of year is the preservation of wildlife habitat during winter months. These late winter burns remove thatch, but they have been insufficient to retard woody invasion at numerous sites, resulting in a major management problem for grassland remnants in Illinois (Robertson et. al. 1996). Woody invasion continues on sites that have a prescribed burn history spanning nearly 50 y (McClain and Ebinger 2012). More than 60% of the area of several grasslands in Illinois has been lost since the 1930s (McClain 1983; Robertson et. al. 1996). Costly, time-consuming tree and shrub removal programs have been implemented to mitigate the woody invasion, but much grassland appears to have been permanently converted to forest (Robertson et. al. 1996). Observations of late-winter burn sites suggest these events also benefit cool-season plant species such as Kentucky bluegrass and smooth brome, allowing them to achieve greater dominance within the plant communities. Nearly 50 y of late-winter prescribed burning may also benefit big bluestem (Andropogon gerardii Vitman.) and Indian grass (Sorghastrum nutans (L.) Nash.). The increase in dominance of these grasses may be contributing to a loss of rare plant species at some sites (McClain and Ebinger 2012; McClain et. al. 2014).

The late-winter prescribed burns of today are conducted during weather conditions that are vastly different from the Indian summer burns of the seventeenth, eighteenth, and nineteenth centuries (Table 2). Fire management has become progressively more complicated with time due to the effects of invasive exotic species, the presence of roads, developments, and communities, strict burning regulations, and a changing climate. These issues make the timing of prescribed burns especially critical when managing to maintain biodiversity and to maintain grasslands. We suggest an assessment of the timing and seasonality of prescribed burns to allow greater flexibility in the application of fire to address current management problems.