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The Historic Role of Fire in Arkansas

Arkansas Natural Heritage Commission - Tuesday, October 08, 2019
by Theo Witsell

Our modern landscape is so different from that of the past that it is hard for us to understand the magnitude of fire’s historic role in shaping plant communities in Arkansas. Before widespread landscape fragmentation and fire suppression, fire was an important ecological force in most upland ecosystems in Arkansas. Plant communities were distributed on the landscape based in part on how frequently and intensely fires burned in different places.

Historically, large, flat plains that weren’t regularly flooded were the sites of our largest open prairies and savannas. Fires ignited at these sites could cover large areas, burning for weeks at a time. Drier upland sites in hilly terrain, such as ridges and south- and west-facing slopes also received enough fire to support open communities. More moist sites on north- and east-facing slopes, below bluffs, along streams, and in deeply dissected terrain generally received less fire and supported naturally closed forested habitats.

Early explorer and settler accounts provide us with a glimpse into our past. Many of these accounts described large areas of the Ozark and Ouachita Mountains as being treeless on the ridges with open oak or pine woodlands and savanna on the slopes, and forests in the valleys, as well as fire-protected areas in canyons and on some north- and east-facing slopes. In the absence of fire, coupled with the intense grazing of domestic livestock and the fragmentation brought on by settlement, this open landscape was encroached upon by the steady march of woody species. Prairie openings, savannas, and woodlands transitioned to shrublands and forests.


Nowhere in Arkansas, perhaps, is this loss of open habitat more evident than in the rocky savannas, glades, and hilltop prairies of parts of the Ozark Plateau. When Henry Rowe Schoolcraft traveled through the White River Hills (in what is now northern Arkansas and southern Missouri) on December 29, 1818, he described the character of the land in the following passage:

“The country passed over yesterday, after leaving the valley of the White River, presented a character of unvaried sterility, consisting of a succession of limestone ridges, skirted with a feeble growth of oaks, with no depth of soil, often bare rocks upon the surface, and covered with coarse wild grass; and sometimes we crossed patches of considerable extent, without trees or brush of any kind, and resembling the Illinois prairies in appearance, but lacking their fertility and extent. Frequently these prairies occupied the tops of conical hills, or extended ridges, while the intervening valleys were covered with oaks …”

Schoolcraft’s rocky barrens and prairies, of course, were not really characterized by “unvaried sterility” in the botanical sense. They supported a tremendous diversity of native grasses and wildflowers. Today, however, one is hard-pressed to find more than a trace of this sort of landscape left in this area. There are a few small open areas, mostly in sites that are used as hayfields or kept open by periodic mowing in road and utility rights-of-way. The majority of these habitats though, in the absence of fire, are now dense and often impenetrable monocultures of the native, but aggressive, eastern redcedar (Juniperus virginiana). See Partnerships Grow, Improving Restoration Efforts and Fish Habitat and Neighbors at Middle Fork Barrens Pitch In To Remove Cedar.

Another striking passage in Schoolcraft’s journal is his description, written on December 9, 1818, of Sugarloaf Prairie and Sugarloaf Knob, just north of present day Lead Hill, Ark. in Boone County:

“…arrived at an early hour in the afternoon at the house of a Mr. Coker, at what is called Sugarloaf Prairie. This takes its name for a bald hill covered with grass rising on the verge of the river alluvion on the west side of the river, and is discernible at the distance of many miles.”

The area he is writing about is now wooded to the top, mostly with cedars, but with several species of hardwoods as well. There are still vestiges of Schoolcraft’s “bald hill covered with grass” tucked away in a few roadsides, powerline cuts, and in the few open areas left on the knob. Native prairie grasses and rare grassland plants like the showy beardtongue (Penstemon cobaea), fringed puccoon (Lithospermum incisum), Trelease’s larkspur (Delphinium treleasei), Nuttall’s dwarf morning glory (Evolvulus nuttallianus), Crawe’s sedge (Carex crawei), and many other now uncommon glade and grassland species, are found in these little nooks. Still, most of the knob is thick with woody plants – nothing beneath them but a few shade-tolerant species and thick layers of leaves and cedar duff (decaying organic matter on the forest floor).

Interpretation of the original General Land Office (GLO) survey notes for the state provides many other examples of our loss of open grassland habitats to fire suppression. For the most part, these records tell us that much of the present-day wooded uplands in Arkansas are considerably denser than they were historically (see The Ecological Time Machine: GLO Records). Similarly, many remnant glades and prairies are smaller than they used to be. We also know that in prairie regions, wooded areas along streams are larger and denser than they once were.


So where does that currently leave us? How do we know if an area would benefit from the reintroduction of fire? Almost any area that has naturally occurring grassland plants will benefit from a burn. Clues to fire-suppressed woodlands are many and are easy to interpret with a little practice. They include the presence of prairie species in sunny spots like roadsides and power line rights-of-way. Sites with swaths of pale purple coneflower (Echinacea pallida), little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), butterfly milkweed (Asclepias tuberosa), and others are likely former woodlands. These species didn’t just arrive on the roadsides and utility lines, those are the only spots left where there is enough sunlight for them to bloom. Another good clue is the presence of old, open-grown oak trees (especially post oaks, but other species too). These are easily spotted by their large diameter, often twisted trunks and spreading limbs (which indicate that they grew in a fairly open situation). They often have the tops broken out of them and are surrounded by younger, more densely spaced trees with straight trunks and compact branches.

Photos:

Top to bottom

Photo 1 - Prescribed burn at Railroad Prairie Natural Area in Lonoke and Prairie counties. Photo by Bryan Rupar.

Photo 2 - Dolomite glade in Baxter County.

Photo 3 - Wildflowers at Baker Prairie Natural Area in Boone County.

Photo 4 - Showy beardtongue (Penstemon cobaea) at White Cliffs Natural Area in Little River County. Photo by Eric Hunt.

Photo 5 - Pale purple coneflower (Echinacea pallida) at H.E. Flanagan Prairie Natural Area in Franklin County.

 

 



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