Theses and Dissertations

ORCID

https://orcid.org/0000-0002-4881-3460

Advisor

Siegert, Courtney

Committee Member

Polinko, Adam

Committee Member

Granger, Joshua

Committee Member

Poudel, Krishna

Committee Member

Freedman, Zachary

Date of Degree

8-13-2024

Original embargo terms

Immediate Worldwide Access

Document Type

Dissertation - Open Access

Major

Forest Resources (Forestry)

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Forest Resources

Department

Department of Forestry

Abstract

Coal strip mining leaves widespread degraded soil throughout the southeastern US. These soils tend to have low pH, high bulk density, impacted hydrologic processes, and an accumulation of heavy metals that limit revegetation and reforestation efforts. Shortleaf pine (Pinus echinata) can tolerate these poor conditions on post-mined sites and has the largest native pine range in the southeastern US, making it an ideal species for restoration efforts. Additionally, the use of soil amendments to improve soil physical and chemical parameters is expected to lead to improved plant establishment and growth. To address the challenges associated with degraded post-mined landscapes, two studies were conducted using a biochar (BC) and microbial amendment (MA). Few empirical studies have been conducted on the success of soil amendments for soil physical properties, chemical properties, and tree growth. To fill this knowledge gap, a three year field trial was established on a reclaimed mining site in Alabama. Shortleaf pine seedlings were planted in a complete randomized block design with two soil amendment treatments: BC and MA. The second study then evaluated how climate change impacts restoration efforts. Specifically, this study observed how precipitation uncertainty affects the effectiveness of existing restoration techniques. This comprehensive 6-month greenhouse experiment in Mississippi examined shortleaf pine restoration under dry and wet moisture regimes. Soil amendments were applied to one year old seedlings replicated across moisture treatments including the same mixtures of amendments as the field experiment in addition to a no tree treatment, a pot with only post-mined soil. Findings from both studies indicate that BC did not improve measured soil properties or tree growth as expected, while the MA induced short-term impacts on soil physical and chemical properties that impacted tree growth. The greenhouse results also indicated that changes in precipitation do not impact the effects of any soil amendment. Additionally, MA may have the potential to change the allocation of biomass for shortleaf pine, which has implications for survival and restoration. In the short-term, the application of commercially recommended levels of treatments were ineffective at supporting tree growth through improvements to measured soil characteristics.

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