Ash Content and Elemental Composition Dataset Assessing the Impact of Fire on Tropical Peat in Badas Peat Swamp Forest

ABSTRACT This article presents data on ash content and selected nutrients from peat samples collected in the Badas peat swamp forest, located within the largest peat dome in Brunei Darussalam, northwest Borneo. Since the late 1990s, the Badas peat swamp forest has been affected by recurring forest fires near a drainage canal constructed in the 1950s. In 2019, two transects (Transect 1 and Transect 2) were set up perpendicular to the Badas canal, spaced 500 m apart. Peat drives were collected from these transects to quantify ash content and the elemental compositions of aluminium, calcium, iron, and magnesium. A total of 25 sampling points, each with 12 peat drives sampled to a depth of 150 cm, were collected from the two transects using a Russian peat corer. Ash contents were measured to evaluate the applicability of the residual ash method in tropical peatlands. The datasets provide insights into the alteration of the physical and chemical properties of peat caused by fire and are relevant to peatland management and climate change mitigation efforts. Additionally, this dataset can support future studies on the impacts of fire in Borneo peatlands. While the residual ash method has limitations in reliably estimating carbon loss in degraded tropical peatlands, the ash content and elemental composition data presented here provide a valuable baseline for understanding fire‐induced changes in peat soil chemistry. These datasets can also support broader ecological assessments, restoration planning, and comparative analyses across tropical peat systems. The Metadata is available in MetaCat in JaLTER at https://jalter.diasjp.net/data/ERDP‐2025‐05 .