Dataset Description

Title

Dataset supporting the manuscript: Hierarchical Controls on Charcoal Signatures: A Framework for Interpreting Paleo-Fire Proxies

Description

This dataset contains the experimental data and supplementary figures used in the manuscript Hierarchical Controls on Charcoal Signatures: A Framework for Interpreting Paleo-Fire Proxies. The study investigates how pyrolysis temperature, combustion duration, and fuel type influence the chemical, isotopic, and morphological characteristics of pyrogenic carbon (charcoal) produced from representative woody (C₃; Alnus glutinosa) and grassy (C₄; Setaria viridis) taxa.

Charcoal samples were produced under controlled laboratory conditions across a temperature range of 200–700 °C and pyrolysis durations of 5–30 minutes. Measurements include benzene polycarboxylic acid (BPCA) composition, elemental composition, stable carbon isotopes (δ¹³C), and particle morphometrics.

The Excel workbook contains 13 worksheets as described below.

Worksheet Description

01_Total dataset

Complete experimental dataset containing all measured variables, including elemental composition (TOC, TN and S), C/N ratio, BPCA data, and stable carbon isotope values for all charcoal samples.

S1

Data used to generate heatmaps of Pearson correlation coefficients between pyrolysis time and key chemical parameters (ΣBPCA and TOC) at different temperature treatments for Alnus glutinosa and Setaria viridis.

S2

Pyrolysis data collection matrix summarizing experimental conditions and sample organization for both species.

S3

Data supporting analyses of relationships between pyrolysis conditions and:

• ΣBPCA (aromatic condensation indicator)

• Total Organic Carbon (TOC)

Used for regression analyses examining the influence of pyrolysis conditions on chemical transformation.

S4

Data supporting analyses of:

• Total Organic Carbon (TOC)

• Total Nitrogen (TN)

• Sulfur (S)

Used to evaluate compositional changes during carbonization across temperature and time treatments.

S5

Stable carbon isotope (δ¹³C) values of Alnus glutinosa and Setaria viridis across all pyrolysis temperatures and durations.

S6

Data used for regression analyses examining relationships between pyrolysis conditions and δ¹³C values for both species.

S7

Morphometric figure containing length-to-width (L/W) ratios of charcoal particles from Alnus glutinosa and Setaria viridis, used to compare species-specific particle morphology.

S8a

Length-to-width (L/W) ratios of Alnus glutinosa across pyrolysis temperatures.

S8b

Additional Length-to-width (L/W) ratios of Alnus glutinosa across varying pyrolysis temperatures.

S8c

Length-to-width (L/W) ratios of Setaria viridis across pyrolysis temperatures.

S8d

Additional Length-to-width (L/W) ratios of Setaria viridis across varying pyrolysis temperatures.

S9

Conceptual framework for a practical workflow for paleo-fire reconstruction. This framework guides charcoal proxy selection and interpretation based on research objectives, dominant controls on charcoal formation, and analytical effort versus information yield.

Methods Summary

Charcoal was produced from woody (Alnus glutinosa) and grassy (Setaria viridis) biomass under controlled pyrolysis conditions. Samples were characterized using:

• Benzene polycarboxylic acid (BPCA) analysis

• Elemental analysis (TOC, TN, S)

• Stable carbon isotope analysis (δ¹³C)

• Fourier transform infrared (FTIR) spectroscopy

• Morphometric measurements of charcoal particles

Associated Publication

These data support the manuscript:

Hierarchical Controls on Charcoal Signatures: A Framework for Interpreting Paleo-Fire Proxies.