Date of Award

Summer 8-11-2018

Degree Type


Degree Name

Master of Science - Environmental Sciences


Environmental Science

First Advisor

Dr. Brian Oswald

Second Advisor

Dr. Kenneth Farrish

Third Advisor

Dr. Rebecca Kidd

Fourth Advisor

Dr. Yuhui Weng


Longleaf pine (Pinus palustris) savannas were once dominant in East Texas and parts of western and central Louisiana. Native understory species have since been removed or reduced by exotic plants that were introduced and from the reduction in the frequency of both wild and prescribed fires. A diverse layer of understory species can still be seen today, but not often in the historical savanna setting that is desirable in longleaf pine ecosystems. This project aimed to identify site characteristics associated with longleaf ecosystems that support a dense, herbaceous understory with little to no midstory cover.

A total of 65 plots were established within the Boykin Springs Area to evaluate the influence of overstory cover, basal area, aspect, elevation, and slope on the number of plant genera. The study area was divided into three sites (A, B, and C) which had differing vegetative parameters and site characteristics such as elevation and slope. Site A had been recently burned as it has and is currently being managed for Red-cockaded Woodpecker habitat. The vegetative parameters and site characteristics had significant effects on the number of plant genera found in those sites.

Six of the plots were confirmed to be on Letney soils and were evaluated for their general soil parameters (sand, silt, and clay content). Equipment used to

define understory and overstory parameters were the spherical densiometer for measuring overstory canopy cover, 1 m² pvc pipe frame for percent cover by growth form, and vinyl measuring tape for little bluestem cover. Due to the small sample size, these plots were not included in the data analysis for the three study sites. These plots were only utilized for their general soil parameters and vegetative composition. Soil texture and series did not have any significant effects on the number of genera on those plots.

Based on the Pearson Correlation method, the number of genera per plot increased with elevation and slope (P=0.0044 and 0.0212, R=0.372 and 0.30207, respectively). This can also be explained by the negative correlation between elevation and both the overstory cover and the basal area (P=0.0918 and 0.0983, R= -0.225 and -0.221, respectively). As elevation increased, there was a decline in basal area and overstory cover which leads to a more diverse, understory layer. Results from this study suggest that in order to promote or restore a diverse, herbaceous understory in historical longleaf pine savannas, efforts to plant specific understory species that are important in restoration efforts should be aimed at areas with open canopy conditions and on slopes with greater solar exposure.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



Tell us how this article helped you.


To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.