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Studying the Savannah

"As my memory goes back over the 46 years in North Carolina the two summers of day after day on the Big Savannah continually surrounded by floral beauty while we engaged in our technical soil studies stand out beyond everything else."

B. W. Wells
North Carolina Wild Flower Preservation Society Newsletter
October 1966

"Strangely enough, to keep a savanna in full wild flower production, it must be burned every year."
North Carolina Wild Flower Preservation Society Newsletter
B. W. Wells
February 1956

Pond (pocosin) pine savannah after a burn
Pinus serotina Michx.

Wells characterizes fire as being of "prime importance" in the maintenance of pine savannahs. Without it, the area is dominated by woody plants, but with it, the area is dominated by perennial grasses and other herbaceous plants. The intensity and frequency of the fires has a direct effect on the site. The amount of living vegetation and vegetation debris, along with climatic factors such as wind speed and direction, contribute to the intensity of the fires, while, according to Wells, humans, not lightning, ignite the annual fires.

LeConte's thistle
Cirsium lecontei Torr. and Gray

Summer aspect of LeConte's thistle

Wells noted the impact of animals upon the savannah plants. Of LeConte's thistle, he notes that it exists solely on the ant hills found throughout the site. In the more poorly drained soils, crayfish and earthworms were found, but were not prevalent enough to have an impact upon the soil or plants.

"A soil layer cake: the high water table of the savannah prevents deep root penetration and rapid decay of organic matter, thus forming a black stratum, one foot thick."

Wells conducted detailed surveys of topography. He looked at the porosity and texture of the soil and measured the oxygen, carbon, total organic matter, and nitrogen he found in the soil. He also took detailed measurements of the water table to see how quickly water drained from the site.

I. V. Shunk and D. B. Anderson at Big Savannah

Wells developed his project on the savannah as a joint venture and created what may have been one of the earliest ecological cooperative programs in the United States. It included Frederic Clements from the Carnegie Institute as well as several members of the college faculty, each brought in to focus on different aspects of the savannah according to their expertise. Shown here are two colleagues examining the soil. On the right is I. V. D. Shunk, who worked on projects with Wells over the course of the next fifteen years, co-authoring many publications, including the one on the Big Savannah.

Vegetational map of Big Savannah and environs showing locations of transects

Wells drew this map to detail the locations of plant communities on the Big Savannah. It shows the location of transects along which he took soil samples and measured changes in the water table. It also details landmarks such as the locations of his field labs in 1925 and 1926 and the railroad track from which he first spied the site.

Spring ladies' tresses
Spiranthes vernalis Engelm. and A. Gray

In 1928, Wells was able to publish the results of his two-year study of the Big Savannah in the article "A Southern Upland Grass-Sedge Bog: An Ecological Study" Coauthored by B. W. Wells and I. V. Shunk, it appeared in the North Carolina Agricultural Experiment Station Technical Bulletin No. 32. He explains that "savannah" is a local term ascribed to the site and a more accurate ecological description is "grass-sedge bog". He lists the species in each of the three major plant communities and explores how habitat factors such as soil, fire, and climate affect the plant succession taking place on the site. Here he describes the site being examined, the purpose of the investigation, and the transect system he used for sampling vegetation. Reflecting the fact that the publication is for an agricultural school, Wells details practical applications for the site, such as using bog plants as indicators of drainage conditions at other sites, or even planting the site with blueberries.

Savannah white orchid
Platanthera nivea (Nutt.) Luer

Wells filled this scientific paper with imagery to help readers to envision the savannah. It features 84 photographs documenting the various species he studied.

"Diagram of stream head showing relation of the communities."
"A Southern Upland Grass-Sedge Bog: An Ecological Study."
North Carolina Agricultural Experiment Station
Technical Bulletin No. 32
B. W. Wells and I. V. Shunk

Along with photographs, Wells uses eleven figures to graphically represent the data he collected on the site. These represent the relationship between humus layer, water table, topography, and species. Along the top are the numbered sites he tested along a transect, while the lines represent the depth of the water table on different dates. For example, on the chart on the left, one can see that at site 15, the water table was lower on each date tested than at the other sites, and the humus layer was thicker.

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