Patterns of soil dissolvable matter following prescribed fire reintroduction in hurricane-damaged southeastern U.S. coastal forest

Authors: BHANDARI, S - Auburn University; ALEXANDER, H - Auburn University; PHIPPS, S - Non ARS Employee; SHRESTHA, B - Auburn University; ADHIKARI, S - Auburn University; OLSHANSKY, Y - Auburn University

Submitted to: Environmental Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2025
Publication Date: 1/3/2026
Citation: Bhandari, S., Alexander, H.D., Phipps, S., Shrestha, B., Adhikari, S., Olshansky, Y. 2026. Patterns of soil dissolvable matter following prescribed fire reintroduction in hurricane-damaged southeastern U.S. coastal forest. Environmental Processes. 13(1). https://doi.org/10.1007/s40710-025-00810-1.
DOI: https://doi.org/10.1007/s40710-025-00810-1

Interpretive Summary: Prescribed fire is a common management practice for restoring and preserving coastal forest ecosystems in the southeastern U.S., which face complications due increasing impact of wind damage on fuel distribution. In this study, we quantified variations in dissolvable organic matter (DOM) to identify changes in carbon and nutrient cycling before, immediately after prescribed fire and up to a year after prescribed. Two coastal forests impacted by hurricane were selected for study. Changes in soil dissolvable organic carbon and nitrogen levels were observed in the study sites. These findings highlight the critical role of prescribed fire in influencing DOM and nutrient dynamics.

Technical Abstract: Prescribed fire is a common management practice for restoring and preserving coastal forest ecosystems in the southeastern U.S., which face complications due increasing impact of wind damage on fuel distribution. In this study, we quantified variations in dissolvable organic matter (DOM) to identify changes in carbon and nutrient cycling before, immediately after prescribed fire and up to a year after prescribed. Two coastal forests impacted by hurricane were selected along the Gulf of Mexico, USA, Perdido River Preserve (FL), and Weeks Bay National Estuarine Research Reserve (AL). At Perdido, a positive correlation was observed between fuel load change and an immediate increase post fire in dissolvable organic carbon (DOC), nitrogen (DN), and carbon-to-nitrogen ratio (C:N). DOC returned to pre-fire levels within a year, while DN levels remained elevated, resulting in a decrease in C:N. The molecular size of DOM reflected by the ratio between absorbance at wavelength 465 to 665 nm increased by 34% at Perdido. At Weeks Bay, the specific absorbance at 254 of DOM decreased by 88% during the first month post-fire, suggesting a relative decrease in aromatic moieties. Increase in humic-like and decrease in small aromatic DOM at Weeks Bay, a year after fire was measured by fluorescence spectroscopy. Increases in potassium and sodium at both sites; immediately after the fire at Weeks Bay and up to one-year post-fire at Perdido. Constant declines in magnesium, silicon, and aluminum at Weeks Bay were seen up to one-year post-fire. Both sites experienced elevated nitrate and reduced phosphate levels, specifically one-year post-fire. These findings highlight the critical role of prescribed fire in influencing DOM and nutrient dynamics.