Physiographic features

Macon Ridge in extreme northeastern Louisiana and southeastern Arkansas is a 135-mile long prominent ridge that lies between the Boeuf and Tensas Basins (Saucier, 1994). Macon Ridge is a terrace that features level to gently undulating topography with steep scarps of uplands, floodplains, depressions, and drainageways. The entire area is located within the Mississippi Alluvial Valley section of the Coastal Plain Province of the Atlantic Plain. It reaches a maximum width of about 25 miles in northeastern Louisiana about 30 miles north of Sicily Island (Saucier, 1994). Elevation ranges from 50 to 150 feet (15 to 46 m). The ridge is consistently higher on its eastern side where elevations are 20 to 30 feet higher than in the adjacent Tensas Basin (floodplain). It is bounded on the eastern edge by Bayou Macon. On the western side, bounded by the Boeuf River, elevations of the ridge are approximately the same as those in the Boeuf Basin, and it is sometimes difficult to distinguish the two at the surface (Saucier, 1994). Both Bayou Macon and Boeuf River are underfit streams occupying ancient Arkansas River meanders. The entire Macon Ridge is underlain by Pleistocene-aged loamy and clayey braided stream alluvium from the “old” Arkansas River. Macon Ridge consists almost entirely of Early Wisconsin age glacial outwash and is a continuation of the valley train in the Western Lowlands (Saucier, 1994). The area mantled by loess on the eastern edge of the terrace rises 10 to 30 feet above the floodplains. The loess thins toward the west, and elevation decreases. The loess in the western part of Macon Ridge contains small mixtures of the older underlying braided-stream terrace alluvium, and in even lower elevations, the loess contains mixtures of recent clayey alluvium or is buried completely beneath recent alluvium (Allen 1993).

This PES occurs on silty, long, narrow ridges, summits, escarpments (short steep backslopes) and steep convex slopes on gently sloping to strongly sloping uplands and terraces on the eastern edge of the loess-mantled Macon Ridge in Arkansas and Louisiana. Slopes are gently sloping to strongly sloping (5 to 20 percent). These sites include ridges, summits and escarpments mainly along the eastern edge of Macon Ridge above the floodplain of Bayou Macon. There are a few small areas of ridges and summits along the eastern side of the Boeuf River.

Table 2. Representative physiographic features

Climatic features

The climate of North East Louisiana and South East Arkansas is warm and humid with a monthly precipitation that is well distributed throughout the year. The monthly precipitation mean is between 2.9 and 5.3 inches, with the lowest rainfall occurring from June through November. The following climatic data are averages from the three weather stations listed below. Temperature and precipitation may vary considerably from that listed for each month. Site specific weather data should be used for land management decisions. For site specific weather conditions, obtain data from a weather station close to the site.

Table 3. Representative climatic features

Climate stations used

• (1) WINNSBORO 5 SSE [USC00169806], Winnsboro, LA

• (2) EUDORA [USC00032355], Eudora, AR

• (3) RAYVILLE [USC00167691], Rayville, LA

Influencing water features

This site is moderately to well drained, sheds runoff and the soils are moderately permeable. There is limited amounts of water that influence the site other than the rainfall that is intercepted and allowed to percolate into the soil profile. Some of the soils will develop a Fragipan or a slowly permeable horizon, these moderately well drained fragipan soils have a seasonal perched water table 1.5 to 3.0 feet in depth and above the fragipan in winter and early spring in normal years.

Soil features

Soils are well drained, Ultic Hapludalfs (Goodwill), well drained, Typic Hapludalfs (Memphis), moderately well drained, Typic Fragiudalfs (Gigger), moderately well drained, Oxyaquic Fraglossudalfs (Grenada), and moderately well drained, Oxyaquic Fragiudalfs (Loring). These soils formed from thick loess deposits and mixed thin loess and loamy sediments of late Pleistocene Age. Slopes range from 0 to 5 percent. These deep to very deep soils are found on long, narrow ridges, summits, and natural levees on nearly level to gently sloping uplands and stream terraces. These soils range from moderately permeable to slowly permeable (within the fragipan). These soils are not considered hydric. The moderately well drained fragipan soils have a seasonal perched water table 1.5 to 3.0 feet in depth and above the fragipan in winter and early spring in normal years. The well drained soils have a water table deeper than 6 feet. These soils are not subject to flooding. These soils have land use limitations: 1) rooting depth restriction due to the fragipan, and (2) susceptible to erosion due to silt loam surface texture and slopes greater than 3 percent.

Table 4. Representative soil features

Animal community

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Hydrological functions

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Recreational uses

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Wood products

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Other products

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Other information

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Other references

Allen, T. E. (1993), USDA-NRCS Richland Parish Soil Survey Report

Autin, W. J., Burns, S. F., Miller, B. J., Saucier, R. T., & Snead, J. I. (1991). Quaternary geology of the lower Mississippi Valley. The Geology of North America, 2, 547-582.

Cowardin, L. M., Carter, V., Golet, F. C., & LaRoe, E. T. (1979). Classification of wetlands and deepwater habitats of the United States. US Fish and Wildlife Service FWS/OBS, 79(31), 131.

Daigle, J.J., Griffith, G.E., Omernik, J.M., Faulkner, P.L., McCulloh, R.P., Handley, L.R., Smith, L.M., and Chapman, S.S. (2006), Ecoregions of Louisiana (color poster with map, descriptive text, summary tables, and photographs): Reston, Virginia, U.S. Geological Survey (map scale 1:1,000,000).

Emerson, F. V. (1918). Loess-depositing winds in Louisiana. The Journal of Geology, 26(6), 532-541.

Ezell, A. W., & Hodges, J. D. (1995). Bottomland hardwood management: Species Site Relationships. MSU Extension Service Publication 2004.

Frost, C. C. Presettlement Fire frequency regimes of the United States: A First approximation. Fire in ecosystem management: Shifting the paradigm from suppression to prescription, ed. TL Pruden and LA Brennan, 70-81.

Guyette, R. P., Stambaugh, M. C., Dey, D. C., & Muzika, R. M. (2012). Predicting fire frequency with chemistry and climate. Ecosystems, 15 (2), 322-335.

Heinrich, P. V., (2008), Loess Map of LA, Louisiana Geological Survey

Kochian, L. V., Pineros, M. A., & Hoekenga, O. A. (2005). The physiology, genetics and molecular biology of plant aluminum resistance and toxicity. In Root Physiology: From Gene to Function (pp. 175-195). Springer Netherlands.

Latimore S. (1996). THE RARE AND SENSITIVE NATURAL WETLAND PLANT COMMUNITIES OF INTERIOR LOUISIANA. Louisiana
Natural Heritage Program, Louisiana Department of Wildlife & Fisheries, Baton Rouge, Louisiana.

Louisiana Natural Heritage Program, Louisiana Department of Wildlife & Fisheries, (2009) The Natural Communities of Louisiana McCraw, David J., and Whitney J. Autin. Lower Mississippi Valley, Loess: A Field Guide. Inqua Commission on Loess, 1989.

Miller, B. J., Day, W. J., & Schumacher, B. A. (1986). Loesses and loess-derived soils in the Lower Mississippi Valley. Guidebook for soils- geomorphology tour.

Miller, B. J., Lewis, G. C., Alford, J. J. & Day, W. J. (1984) Loesses in Louisiana and at Vicksburg, Mississippi. Guidebook for Friends of the Pleistocene Field Trip.

Muery, E. (1998), ANALYSIS OF PRESETTLEMENT NATURAL PLANT COMMUNITY TYPES OF THE MACON RIDGE OF LOUISIANA.

Pettry, D. E., & Switzer, R. E. (1998). Sodium soils in Mississippi.

Saucier, R. T. (1994). Geomorphology and Quarternary Geologic History of the Lower Mississippi Valley. Volumes 1 and 2. ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB.

Schumacher, B. A., B. J. Miller, and W. J. Day. "A chronotoposequence of soils developed in loess in central Louisiana." Soil Science Society of America Journal 51.4 (1987): 1005-1010.

Theriot, R. F. (1992). Flood tolerance of plant species in bottomland forests of the southeastern United States.

United States Salinity Laboratory Staff, USA, USDA (1954), Diagnosis and improvement of saline and alkali soils, USDA Agriculture Handbook 60, 1954, 160 pp.

USDA Agriculture Handbook 296. (2006). http://soils.usda.gov/MLRAExplorer. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin.

USDA Natural Resources Conservation Service. Published Soil Surveys from Catahoula, Franklin, Richland and West Carroll Parishes. Various publication dates.

USDA Natural Resources Conservation Service. Web Soil Survey, http://websoilsurvey.nrcs.usda.gov/app. USDA NRCS Soil Survey Division. Washington, DC. 2008.

Contributors

D Charles Stemmans II
Rachel Stout Evans
Wayne Roberts
Dwayne Rice

Acknowledgments

The Macon Ridge Technical Team did an outstanding job of utilizing existing data and knowledge to develop site concepts. They also provided the needed sections of the descriptions, review and comments of them.