Semester of Graduation

Fall 2026

Degree

Master of Science (MS)

Document Type

Thesis

Abstract

Productivity decline between rotations has long been a concern in intensively managed forest plantations. Research done over the last century has provided greater clarity on why this phenomenon occurs. The objective of this research was to observe long-term soil and tree growth characteristics that are likely to be influenced by operational harvesting activities. The experiment was conducted in Washington Parish, Louisiana on a site dominated by Ruston soil series, a well-drained, fine loamy, siliceous and thermic typic Paleudult. A randomized complete block design with 2 x 2 x 2 factorial treatments was used. The treatment factors were harvesting method, fertilization, and site preparation, each with two levels. Harvesting treatments consisted of a minimal-disturbance, hand-felled bole-only harvest or a conventional whole-tree harvest. Fertilization treatments consisted of no fertilizer or an application of diammonium phosphate. Site preparation treatments consisted of no burn or broadcast burning. The eight treatment combinations were assigned to 24 plots within three blocks, resulting in three replicates per treatment combination. Soil bulk density and potential mineralizable N were measured in 2002 (pretreatment), 2004 (initial posttreatment), and 2025 (final posttreatment), while soil chemical properties (C, N, P, K, Ca, Mg, Na, C:N, and pH) were measured in 2004 and 2025. Tree height and diameter at breast height measured in 2020 were used to evaluate long-term treatment effects on growth. Although soil bulk density increased in hand-felled plots following harvest, most significant long-term harvesting effects on soil physical and chemical properties occurred in conventionally felled plots. Conventional harvesting was associated with long-term increases in soil bulk density and elemental content in the mid-layer of soil 20 years post-harvest, indicating that bulk density recovery was not uniform and that site-specific conditions or accompanying site preparation may alter harvesting responses. Fertilization and burning interacted with other treatments and, depending on the response, dampened or amplified treatment effects. Fertilization provided long-lasting soil P additions associated with improved tree growth, whereas burning reduced initial growing-site quality and was associated with lower long-term height and diameter growth.

Date

8-13-2026

Committee Chair

Dean, Thomas J.

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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