Fire in the Ozarks

Fire has spread through the grasslands, forests, and open woodlands of the Ozarks for thousands of years. It kills some life forms, but sets the stage for others to flourish. Fire can be a driving factor that influences how natural communities of plants and animals develop within ecosystems.

Scientists are studying remnants from long-dead trees, and the growth rings and fire scars within them, to 'read' a tree's history as accurately as we can measure rainfall in a rain gauge or temperature with a thermometer.

Research conducted by scientists at the University of Missouri, USDA Forest Service Northern Research Station, Mark Twain National Forest, and other institutions has revealed when, where, and how fire swept across the Ozarks, and its long-term impacts.

These fire-scar histories are supplemented with human population records, archaeological findings, historical texts, and  charcoal and pollen preserved in ancient pond sediments .

A major finding is that humans, past and present, have played a significant role in fire's impact in the Ozarks.

In this StoryMap, we'll show how fire has shaped Ozark forests and woodlands for centuries, and how lack of fire during the last hundred years has profoundly altered these ecosystems. We also look at modern efforts to re-introduce fire into these landscapes. Our story focuses on the Current River watershed in southern Missouri, USA, which has been well studied by fire history researchers, and which has been home to both Native Americans and European-Americans.

First, let's look at the stories trees can tell, and how scientists interpret them. Dendrochronology, the scientific method of dating based on analysis of tree-ring patterns, starts with a cross section from a stump, or an archeological timber section, or a straw-sized core sample removed from a living tree.

Tree-ring increment core samples taken from living eastern redcedar (Juniperous virginiana) trees.

While collecting core samples with an increment borer can determine a tree's age and growth patterns, many pieces of information - such as fire scars - can be missed using this technique, due to the small size of each core sample. Better information about fire can be gathered by cutting a tree and examining the entire surface of the stump. Remnants from trees that died long ago - whether a stump cut during harvest or a snag (a standing dead tree) - can be mute carriers of stories that tell of forest conditions far into the past.

Researchers know that narrow tree rings indicate poor growing conditions, such as drought, when the tree couldn't grow much during an individual year. Wider rings reflect prosperous conditions, such as plentiful rainfall. Scars indicate an injury to the tree's growing tissue, such as being burned during a fire, which subsequently healed over but left a permanent mark.

Next is a photo series showing the process of collecting shortleaf pine (Pinus echinata) samples and analyzing them in the lab. (Click directly on a photo to see it enlarged. Click arrow to see next photo.)

Patterns of tree growth over decades are consistent among regions and tree species. Crossdating is used to identify an exact year for each ring of a tree. This foundational technique of dendrochronology matches tree-ring patterns, which reflect each tree's growth in response to variations in climate conditions over time.

Using crossdating, researchers can match tree rings from a sample with unknown dates, for example, from a stump in the woods, with tree-growth chronologies from known years. In many cases, dating new samples can extend the chronologies of known dates further into the past. Using this technique, annual records of tree growth have been developed that go back hundreds of years. With data from many samples, taken together, tree rings reveal a remarkable history of droughts, fires, and human interaction with forests.

Scientists across North America have collectively examined fire scars in more than 37,000 tree samples representing 91 tree species, collected coast to coast from more than 2,500 sites.

These fire-scar records were recently assembled and published, creating the  North American Tree-Ring Fire-Scar Network. 

The oldest tree among these records is a giant sequoia that started growing more than 3200 years ago. A ponderosa pine in northeast Arizona germinated in the year 735. Tree samples from more than 200 sites have fire scars dating to the year 1500 or earlier.

This research has offered insight into past climate and past forests throughout North America. For example, fire scar data is an integral part of the  Physical Chemistry Fire Frequency Model  (PC2FM) (Guyette et al. 2012). Developed by the Center for Tree-Ring Science, it estimates historical fire frequency (for the period prior to 1850), as seen in the accompanying map, which was generated by the PC2FM model. The model predicts an average historical fire interval of 6 to 10 years in the Ozarks.

Researchers are continuing to find and analyze fire-scarred tree stumps and snags across North America, but these are disappearing with time. Land use practices such as clearing for agriculture have reduced the number of old, dead trees available for study. In moist climates, decomposition can quickly render stumps unusable, or, in other areas, prescribed fires or wildfires consume old stumps. Thus, current research efforts are vital to find and preserve old tree remnants before they are gone.

The  Center for Tree-Ring Science  at the University of Missouri houses some of the oldest tree samples from the eastern US, including fire-scarred cross sections from more than 40 study sites in the Ozarks.

"Our Center has a long history, an important history working in the Ozark mountains of southern Missouri and northern Arkansas," said Joe Marschall, Senior Research Associate with the Center for Tree-Ring Science. "There’s an incredible, globally significant wealth of old wood in the Ozarks, much more than in many other places in the country."

On record at the Center are  data  and specimens for more than 700 old Ozark trees. Ongoing fire history research in the Missouri Ozarks includes samples from an additional 400 fire-scarred shortleaf pine trees.

Other Ozark tree species that have contributed to the historical record include post oak (Quercus stellata) and eastern redcedar (Juniperus virginiana).

Eastern redcedar can be a long-lived tree species, but they are often killed during fires, so they were less common in times when fires occurred frequently. However, some cedars survived for centuries along bluffs, or in rocky glades and other places that fire couldn't easily reach, as seen in this drawing by Guyette of an old redcedar growing between rocks.

Due to their vulnerability to death by fire, cedars only provide a small part of the dendrochronological record in the Ozarks. But there's another tree with characteristics that make it an ideal species for fire-scar studies.

Shortleaf pine trees are adapted to recurring fire. The seeds germinate best when they fall to bare ground following a fire.

Very rare for a conifer species, if shortleaf pine seedlings are top-killed (such as by fire) they can resprout from a protected bud at the base of the seedling.

When mature, these pines' thick protective bark might be charred in a fire, but the living tissue, the cambium, below the bark may not actually be injured.

When heat does kill the cambium, a scar is formed and in subsequent years the tree grows around the scar. In that case, the fire scar becomes part of the tree's permanent record, revealing to scientists the year - even the season - that the fire occurred. Slides below show some of shortleaf pine's fire-adapted characteristics.

Shortleaf pine flourished for centuries in southern Missouri, until much of it was cut around 1900. But their stumps can still be found across the Ozarks. From them, researchers at the Center for Tree-Ring Science have gained knowledge about Ozark fire and human history in past centuries.

A number of Ozark shortleaf pine stumps analyzed by the Center for Tree-Ring Science contain fire scars dating back to the 1500s, including samples found at four sites in the Current River watershed.

The evidence found in shortleaf pine stumps clearly shows that historically fires occurred regularly in the Ozarks, and over a wide area. Fire scars were found at all 40-plus Ozark research sites, with some places showing fires as frequently as every year (often on ridge tops), but fire was less frequent in other places, such as steep, heavily dissected areas near rivers. Generally, fires were most frequent in the middle-to-late 1800s, and fires were less frequent before and after.

Historically, as now, people needed fire for survival, and fire's impact on a landscape is a reliable signature of human habitation, regardless of whether any given fire was set intentionally to achieve a purpose or merely escaped control. Although lightning can occasionally cause ignitions, the vast majority of fires in the eastern U.S. are human caused, as shown on the accompanying map.

Continent wide, fire had a wide variety of uses for Native Americans. Documented uses of fire by Indigenous people included burning land to promote new plant growth for animal forage; to drive game animals and encircle them; to make easier the collection of foraged seeds, nuts, acorns, and bulbs; to increase berry production; to obtain basket materials; and to clear land to plant crops, among others. Fires were also used aggressively, such as to drive people into an ambush or to chase off poachers and trespassers. Smoke could convey messages, and fires reduced brush, making travel easier.

Studies have shown direct relationships between historical populations and fire frequency in a given area ( Guyette et al. 2002 ). Generally, across the eastern US, "when Native American populations were relatively high, there was frequent fire," Marschall said. "And during periods when it is known that fewer people were living in a region, there was very little fire."

In the Ozarks, during periods of infrequent fire, trees are free to grow, and areas become more densely forested. With frequent fire, some trees die and the forest canopy is reduced; then grass and other herbaceous plants become more abundant, creating woodlands or savannas dominated by fire-adapted species, including shortleaf pine. Scattered trees with plenty of forage below them would have been beneficial to both Native Americans who hunted wild grazing animals and to incoming Europeans raising livestock.

"This pattern, the 'wave of fire,' is strong," Stambaugh said. "It's repeated continent-wide, but the drivers behind it are diverse and varied." As researchers pair fire-scar records with other bits of known human history, it's generating a new storyline, which is still unfolding.

 Click here  to watch Stambaugh's, "Wave of Fire: The Historical Signal of New World Colonization," a 'Fire AFEx Talk,' which was presented at the  7th International Fire Ecology and Management Congress  in 2017.

In a  2002 study  led by Richard Guyette, researchers examined shortleaf pine snags and stumps at 27 sites within the Current River watershed in southern Missouri.

Fires were relatively rare in the earliest years recorded at these locations. At one site, near Blue Spring in Shannon County - which is representative of sites throughout the watershed - fires were recorded in only 11 years during a 150-year period, from 1600 through 1750.

During this time, the Osage and Quapaw hunted in the area. Through the 1700s, the Osage dominated vast territories within the Ozarks, but most Osage settlements were further north, along tributaries of the Missouri River, so population in the Current River watershed would have been sparse, and limited to hunting excursions, which likely explains fewer fires recorded between 1600 and 1750.

In the late 1700s, fires increased significantly across the Current River watershed. For example, at the Blue Spring site, 19 fires were documented in just 58 years, between 1750 and 1808. After that, the Osage, whose population had decreased substantially, left the region, having submitted to an 1808 treaty that forced them west, almost out of Missouri.

Fires became even more common in the Current River watershed after 1808. Native American groups that had been pushed west, such as the Cherokee, Delaware, and Shawnee, entered areas that the Osage had vacated, and some of them spent time in the watershed. European-Americans, too, were beginning to migrate in. (Stevens, 1991; Burns, 2004)

Demonstrating how higher population and higher fire frequency go hand in hand, records show that the population density in the Current River watershed study area became almost 100 times greater between 1750 and 1900, increasing from about .11 persons per square mile to 11. On average, evidence of fire showed up in only about 10 percent of Current River study sites in any given year during the period of lower population (1600-1750). Later, when populations were higher (late 1800s), an average of 40 percent of study sites recorded fires in a given year.

The Blue Springs fire-scar history graph above illustrates the variability of any given fire's impact on individual trees. "Not every tree records every fire that occurs at a site, and therefore a group of trees best tell us what happened there," said Marschall. Even within this relatively small study site, about 250 acres, many individual trees were not scarred by many of the fires. Very few fires scarred a high percentage of trees, and those that did would have likely been larger or more severe fires.

Relatively high fire frequency in the Current River watershed continued during the late 1800s. This represents the period of Euro-American colonization and a "timber boom" in the Ozarks. This economic boom involved harvests that extracted huge amounts of shortleaf pine and oak timber between 1880 and 1920, which resulted in vast areas of heavily cut-over forests with little remaining financial value. Logging slash left on the ground during harvest provided extra fuel for destructive fires during this period.

In an effort to regrow forests, the federal government purchased former timberland throughout the East. In southern Missouri, the Mark Twain National Forest was created in 1934. The Missouri Department of Conservation formed shortly afterward, and part of their mission, too, was to manage regrowth in state forests. Both state and federal agencies implemented policies to suppress fires. Fire lookout towers were built, and "Smokey Bear" campaigns sought to persuade residents to abandon longtime practices of burning their woods and fields. Fire frequency in the Current River watershed was drastically reduced after about 1925, and only a handful of fires were recorded in the study area after 1960.

Some early 1900s Ozark residents resisted the Smokey Bear messaging, and they hung onto their woods-burning traditions for many years after fire-suppression efforts began. One Ozarker, Howard Smith, clearly recalls community-wide controlled burns in his youth and young adult years. He was born in 1928 and raised near Summersville, Missouri, only a few miles from the Current River.

Open range grazing was a longtime tradition during the early decades of the 20th century. Smith's and his neighbors' livestock had access to vast woodland acres in Shannon County, Mo., owned by a big lumber company, in an unbroken block stretching north for many miles from his family's farm. Every year, he said, neighbors would coordinate efforts to burn the annual accumulation of leaves on this open rangeland, which stimulated grass growth for their stock. "I can remember just walking out in the woods and it was nothing to see grass, knee high," he said.

In 1969, Shannon was the last county in Missouri to close the open range. After that, local folks' incentive to burn large areas ended, which aided conservation agencies' fire suppression policies. Now, thick leaf litter blocks plant growth on the forest floor, which Smith attributes to a lack of fire. He said huckleberry bushes (the local term for Vaccinium pallidum, also known as lowbush blueberry), once thick with berries, now seldom bear fruit, and it's been years since Smith has seen hazelnut bushes (Corylus americana), which were prolific in his younger days.

A  fire history study  in the Boston Mountains in the northwest Arkansas Ozarks yielded findings consistent with those at the Current River sites, with a strong correlation between population density and fire frequency. Few fires occurred there in the 1700s, when the region had a low population, and fires were more frequent during the 1800s, when Native Americans, primarily Cherokees, moved into that area. Further, during times of low population, sites on the more accessible perimeter of these mountains showed evidence of more frequent fire than sites in the steep interior, suggesting that rough terrain is an impediment to fire.

That study also found that fires were more widespread during drought years, particularly in the latter half of the 1700s, with fires occurring in both the Current River sites and Boston Mountain sites during dry periods. Fire-scar data from Arkansas and Missouri sites indicate “this landscape had rotation intervals for large-scale fires that approached phenomenal," wrote Guyette, the study's author. “Fires occurred over large sections of the Ozarks … during moderate to extreme drought years.” He calculated that the cumulative area burned in approximately 20-year rotation intervals (during the 1700s) equaled the size of the entire Ozarks (50,000 square miles). These fires would have varied in their intensity and severity.

Guyette calculates that during the latter half of the 1700s, over the course of about every 20 years, the total of areas burned was equivalent to the size of the entire Ozarks.

Below is a link to a six-minute video compiled by Stambaugh that shows, year-by-year, when historical fires have been documented by fire scars in 26 study sites within the Current River watershed.

Consider as you view this video that not every fire will scar trees, so some sites may have experienced more fires than are recorded. While the earliest years depicted (starting at 1561) show fewer fires than later years, keep in mind that fewer tree samples date back that far, so less evidence is available. And although some stumps and snags have withstood decay for more than 100 years in the Ozarks' moist climate, fire scar records here generally do not date earlier than the mid-1500s, so fire history and its relationship to human history prior to that time is not known. Watching this, one could reasonably conclude that fires were common in the Ozarks during the time period shown, 1561-1930.

Prescribed fire is being used for a number of management purposes on the Mark Twain National Forest in south central Missouri, including the goals of promoting shortleaf pine and improving wildlife habitat.

However, those fires put at risk long undisturbed pine stumps and snags containing valuable ecological records. Therefore, in 2020 the Ecology Programs for the Mark Twain National Forest and the USDA Forest Service Eastern Region, partnered with the Center for Tree-Ring Science to collect and analyze remnant pine in a landscape-scale study encompassing more than 325,000 acres.

The study is being conducted because "those stumps are not going to be there forever, and we care about the ecological and cultural history that they contain," said Forest Ecologist Kyle Steele, who helped jump-start the Mark Twain study.

Previously, very few shortleaf pine samples were sourced from this area, much of which lies on a gently rolling plain, with different topography, and hence a different fire history, than some of the more steep and rugged fire history sites along the Current River.

"We try to base our use of prescribed fire on solid science," said Steele. "This study will give us a more robust dataset that we can directly apply, to make good decisions on the ground." The dataset could influence a future version of the Mark Twain National Forest Management Plan, he said.

As of early 2024, Forest Service staff and researchers had collected cross sections from more than 400 long-dead shortleaf pines from the Eleven Point and Current River watersheds. These ancient trees are yielding insight into the history of this region over the past 500 years, including fire regimes, forest regeneration, growth rates, forest stand dynamics, forest density, and even human history.

As seen in the slides below, Forest Service staff have spent many hours collecting samples from old shortleaf pine stump and snags.

Many shortleaf pine stumps and snags collected for the Mark Twain study are found in forests not currently comprised of that species.

More often stands today are dominated by oak and hickory, sometimes with no living shortleaf pine trees in sight. But the old, dead wood scattered on the forest floor reflects a historical forest composition dominated by pine.

In the seven-minute video below, "Fire Scar Research in Historically Pine-Dominated Ozark Forests," Marschall finds old pine stumps in the woods and interprets their growth and fire scar history.

Fire exclusion policies following the timber boom allowed tree growth to recover in the Ozarks, but the resulting forest composition varied greatly from previous times. Open woodlands had been maintained by fire in earlier years, but in the absence of fire, trees grew freely into the dense forests of today, which are primarily oak-hickory communities.

Shortleaf pine is in this mix, but in smaller numbers than historically, as it does not compete well without fire to hold back other species. A  2013 study  found that Ozark forests in the early 2000s were about 2.3 times as dense as those recorded by surveyors in the early-to-mid 1800s, and that fire sensitive species such as maple and eastern redcedar are gaining in dominance. Other studies show that many species that thrive in burned areas have declined, such as tall larkspur and Eastern collared lizard.

Recently assembled fire histories, when put in juxtaposition with today's landscape, raise questions about how to translate fire history information into best land use practices going forward.

"What's our role with fire, our relationship to it, as a people?" asks Stambaugh, the Center's director. Some societal values, such as protecting structures from flames and protecting medically sensitive people from smoke, discourage fire use. These values can compete with environmental values, such as encouraging habitat for disappearing fire-adapted plants and animals. Many wildlife species benefit from fire, including deer, turkey, quail, many migrant neotropical birds, and also a multitude of plant species that provide food and habitat.

A number of Ozark landowners are now seeing value in prescribed fire and are using it to develop open woodlands that emulate historical conditions, with large components of shortleaf pine and native groundcover, along with oaks and hickories.

Among their motivations are to expand wildlife habitat, increase biodiversity, reduce risk of wildfire, produce livestock forage, control biting insects, and enhance aesthetic enjoyment of the landscape.

To achieve these goals, many landowners are joining Prescribed Burn Associations (PBAs) to share experience and equipment, helping each other burn their properties safely. "Interest has bloomed as more people see the positive results these PBAs are achieving on the landscape," said Mark Howell, president of the  Missouri Prescribed Fire Council.  The number of PBAs operating in Missouri more than doubled during 2023, from five to 11.

Public land agencies and not-for-profit groups are also managing land with fire, and some are doing it in a big way.

Missouri State Parks has conducted burns since 1976, with 50-100 burns annually among 35 state parks. Ken McCarty, Missouri State Parks Natural Resources Management Program Director, says there is a big difference between park lands where fire is not used, and where prescribed fire has been applied for 20-30 years. It's like "night and day," he said, because the open woodlands in fire-managed areas are beautiful, filled with birds and butterflies. Visitors might not realize it, but it's fire that provides that pleasing backdrop, enhancing their experiences and "the memories they take home from those parks," he said.

In the Mark Twain National Forest,   managers annually burn  about 49,000 acres, with fire applied to any given tract roughly every 3-10 years.

Forest Service Burn Boss Tim Perren says fire helps the landscape. “We use it to remove the leaf litter and pine needle cast, and to try to kill the smaller saplings in the understory. This allows native herbaceous plants to sprout, which ultimately will improve wildlife habitat,” he said.

At the Chilton Creek Research and Demonstration Area near Van Buren, Missouri, is managed by The Nature Conservancy with prescribed fires for more than two decades, fires have thinned the forest canopy, allowing sunlight to reach the ground. Plants favored by wildlife have thrived there. The Missouri Department of Conservation bought the property in 2023.

The transition in recent decades from near-universal fire suppression to the expanded use of prescribed fire has not been without difficulties. Unexpected outcomes occur as managers learn to apply fire. Residents, some fearful of mishaps or concerned about ruining the timber, have been critical or oppositional.

Burn Boss Perren recounts an incident in the Current River Pinery, in Carter County, Missouri, in 2013, when a 10-acre area burned hotter than anticipated during a Forest Service planned fire. It killed a number of smaller trees and some overstory trees. “Some folks were a little excited about it, thought it was all bad,” Perren said. These results, very visible from a highway, added fuel to an   existing controversy   about burning. But later, “most of the trees that were scorched pretty high, overstory trees, shook it off,” he said. What’s more, “we got a carpet of small pine regeneration in the understory, an ocean of small pine trees came in behind that disturbance.”

"Early on, some people were determined to stop us," Perren said. But the fear and criticism blew over, mitigated mostly by people seeing vigorous trees. In recent years, "I haven't heard a peep, politically or socially," in opposition to fire management in the Current River Pinery, he said.

Another incident of resistance to fire use was a   public outcry   in 2015, in response to a U.S. Forest Service plan to use thinning and burning on about 18,000 acres in Barry County, Missouri, with the intent of restoring degraded glades and woodlands. The project brought out worries about smoke, soil erosion, marring aesthetic views, and the possibility of a destructive escaped fire. However, the restoration effort was supported by environmental groups, who saw it as an   ecologically sound proposal . In the   final decision , the Forest Service reduced the project scope to about 5,000 acres in response to public opposition.

Pioneer Forest, owned by the   L-A-D Foundation   since 2004, has struggled about whether and how much to use fire. The forest, operated on nearly 150,000 acres since the 1950s, has produced oak and pine timber using a single-tree selection silviculture method, without fire. But in recent years staff have gradually begun applying prescribed fire, especially in natural communities that would benefit from burning. The decision to attempt even a small prescribed fire came after years of discussions and study, said Foundation President Susan Flader. Not everyone was comfortable; perspectives differed about whether fire was good management.

After a carefully prepared, small-scale fire in 2009 was successful, prescribed fire management grew in subsequent years to cover more than 2,000 acres; it has helped restore overgrown glades and rejuvenate faltering fire-dependent plant species.

But trouble erupted in 2015, when logging slash was lying on the ground near valuable, mature scarlet oak trees, which have thin, fire-sensitive bark. Such debris is a "jackpot of fuel" said Pioneer Forest Manager Jason Green, which is "going to cook the stems." That fire caused heavy scarlet oak mortality, upsetting board and staff, Flader recounts. Re-evaluation followed, but the organization did not abandon the use of fire. Now, staff plan for strategically removing vulnerable scarlet oak as part of woodland restoration.

Photos below show action and results from Pioneer Forest's fire program.

Despite occasional conflicts and setbacks, fire use is becoming more common and more accepted.

The USDA Forest Service offers an opportunity for the public to view locations where prescribed fire has been used regularly. The self-guided auto tour of the Current River Pinery features five sites in the Mark Twain National Forest where managers have conducted prescribed fire every 3-5 years since the 1990s.

Accompanying each site is an interpretive sign and explanatory podcast, in which regional experts - including aforementioned interviewees Stambaugh, Perren, McCarty, and Flader - tell more about what visitors are seeing.

This tour is also available in virtual format via the website of the   Oak Woodlands and Forests Fire Consortium. 

"A clear picture has developed regarding historical fire frequencies," Marschall, summing up the Center for Tree-Ring Science's extensive data collected over many years in the Missouri Ozarks.

"We see that fire was common in all of the periods, documented by tree rings, from the 1500s on, all the way until the early 1900s, when fire suppression was successfully enacted as a policy in the region," he said. Further, we also know that shortleaf pine trees used to be much more prevalent across their range in the Ozarks than they currently are now. Other fire-adapted tree species, groundcover plants, and wildlife species that were formerly common are now found in fewer numbers.

Ozark fire history informs modern forest management. It illustrates the necessary role that fire plays in maintaining certain natural communities, such as ecosystems associated with shortleaf pine woodlands. More and more data show that a return of fire to the landscape is beneficial for many fire-adapted and fire-dependent species, including plants, pollinators, songbirds, deer, turkey, and other species, and it ultimately benefits people.

"Now that we know the benefits of managing landscapes with fire, fire use may be a cultural obligation and responsibility" in order to "leave environmental conditions in an improved state for future generations." - Michael Stambaugh

Many entities and individuals provided support and assistance for this multimedia product. We thank our interviewees for providing content and for reviewing their sections, and we thank our pre-publication readers for input.

We are grateful to the staff at the Osage Nation's Wahzhazhe Cultural Center library for assistance researching their historical use of fire, and we thank other Osage members for their time and willingness to share insights regarding fire.

The   Joint Fire Science Program   provided financial support.

The   Center for Tree-Ring Science   provided fire history and fire science content, and tree cross-section photos. Additional fire science content and photos were provided by this StoryMap's publisher, the   Oak Woodlands and Forests Fire Consortium .

Remaining photos are by Denise Henderson Vaughn unless otherwise noted. Maps are by Vaughn unless otherwise noted.

Photos and graphics are copyrighted. Please ask permission before publishing elsewhere.

Balch, Jennifer K., Bethany A. Bradley, John T., and Adam L. Mahood.   Human-started wildfires expand the fire niche across the United States , PNAS, 2017.

Brewer, P.W., M.E. Velásquez, E.K Sutherland, and D.A. Falk.   Fire History Analysis and Exploration System (FHAES) , 2016.

Burns, Louis F., A History of the Osage People, University of Alabama Press, 2004.

  Current River Pinery Tour . Oak Woodlands and Forests Fire Consortium website, accessed 7/2023.

  Data.   Center for Tree-Ring Science, accessed 7/2023.

Guldin, James. “  A History of Forest Management in the Ozark Mountains,  ” in Pioneer Forest: A Half Century of Sustainable Forest Management in the Missouri Ozarks, USDA Forest Service Southern Research Station, 2008.

Guyette, R. P., R. M. Muzika, D. C. Dey.   Dynamics of an Anthropogenic Fire Regime , Ecosystems, 2002.

Guyette, Richard P., Michael C. Stambaugh, Daniel C. Dey, Rose-Marie Muzika.   Predicting fire frequency with chemistry and climate,   Ecosystems, 2012.

Guyette, Richard P., Martin A. Spetich, Michael C. Stambaugh.   Historic fire regime dynamics and forcing factors in the Boston Mountains, Arkansas, USA , Forest Ecology and Management, 2006.

Hanberry, Brice B., John M, Kabrick, Hong S. He.   Densification and State Transition Across the Missouri Ozarks Landscape , Ecosystems, 2013.

Krech, Shepard III, The Ecological Indian, W.W. Norton & Company, 1999.

Margolis, Ellis Q., et. al.   The North American tree-ring fire-scar network , Ecosphere, 2022.

Nanavati, William 'Buzz.'   Climate and land use as drivers of Holocene vegetation and fire history in the Ozarks , Online webinar, Oak Woodlands and Forests Fire Consortium, 2020.

Navanti, William, Eric C Grimm.   Humans, fire, and ecology in the southern Missouri Ozarks, USA  . The Holocene, 2020.

Stambaugh, Michael,   Wave of Fire,   Fire AFEx Talk, 2018.

Stambaugh, Michael C., Joseph M. Marschall, Erin R. Abadir, Benjamin C. Jones, Patrick H. Brose, Daniel C. Dey, Richard P. Guyette.   Wave of fire: an anthropogenic signal in historical fire regimes across central Pennsylvania,   USA, Ecosphere, 2018.

Stevens, Donald L., Jr., A Homeland and A Hinterland: The Current and Jacks Fork Riverways, National Park Service, 1991

Wilson, Terry P. The Osage, Chelsea House Publishers, 1988.

Wolferman, Kristie C. The Osage in Missouri, University of Missouri Press, 1997.