Date of Award

Winter 12-16-2017

Degree Type


Degree Name

Master of Science - Environmental Sciences


Environmental Science

First Advisor

Kenneth W. Farrish

Second Advisor

Brian P. Oswald

Third Advisor

Yuhui Weng

Fourth Advisor

Kathryn R. Kidd

Fifth Advisor

Tyson M. Hart


There has been a large decline in coverage of longleaf pine (Pinus palustris Mill.) within its range in the southeastern United States since the time of European settlement. Due to this decline, interest has developed in the re-establishment of this species on suitable sites. However, many attempts have been unsuccessful in re-establishment, likely in part due to the lack of emphasis on selection of suitable soils. Historically, longleaf pine was found on soils with a wide range of soil properties, including higher quality soils, due to frequent fires which kept many competing species suppressed. Decline in longleaf pine coverage has been attributed to many factors, including both site conversion and fire exclusion. Much of the land that originally supported longleaf pine in the southeastern United States has been converted to agricultural use, loblolly pine (Pinus taeda Mill.) plantations, and urban development. Fire has often been excluded from longleaf pine ecosystems in recent history due to concern for human health, safety, and liability. Because of limited funding and reduced opportunities for prescribed fire use, longleaf pine ecosystem restoration efforts might be best focused on more marginal soils that have characteristics that naturally restrain herbaceous and hardwood competition. However, there is a need to quantify the potential productivity for longleaf

pine on these marginal soils and to develop understandings of edaphic factors limiting their growth.

Soil morphological, physical, and chemical properties in existing longleaf pine ecosystems on three soil series in the Angelina and Sabine National Forests in east Texas were evaluated to develop a better understanding of how variation in soil properties may affect longleaf pine site quality. Analysis of variance and regression techniques were used to compare soil properties for three different soil mapping units: Letney (Arenic Paleudults), Stringtown (Typic Hapludults), and Tehran (Grossarenic Paleudults). These soils all support natural longleaf pine stands, but vary in texture, depth to argillic horizons, nutrient availability, available water capacity, and other parameters which are likely related to site quality, as measured by site index, of longleaf pine.

Longleaf pine site index was influenced by depth to E horizon, depth to first argillic B horizon, texture of B horizon, and nutrients in the B horizon. B horizon physical and chemical variables appeared to be most influential on observed site index values for longleaf pine on the soils in the study.



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