Quantifying physical changes in near-surface soil during prescribed fire

Abstract

Prescribed fires are conducted to reduce accumulated fuel loads and maintain fire-dependent vegetative species and wildlife habitats. Few studies have examined the impacts prescribed fires have on near-surface soil-water dynamics. Fire-induced changes in soil temperature, moisture content, water potential, infiltration capacity, and aggregate stability were measured during experimental fires (fuel loads: 0.5, 2, and 5 T acre??) and a prescribed fire conducted in the field (1.7 T acre??). Burns at fuel loads less than 2 T acre?? caused small changes in soil moisture content and water potential, while burns conducted at fuel loads greater than 5 T acre?? may reduce soil moisture content and prolong increased temperature in near-surface soil. Burns aimed to remove invasive vegetation should be conducted at fuel loads greater than 4.2 T acre?? to achieve the 60?C threshold for root mortality; however, land management may need to plan for erosion control in these burn situations.