Investigating the Effect of Oxidants on the Quantification and Characterization of Charcoal in Two Southeast Australian Sedimentary Records

Fire

article

Mark Constantine IV¹  Xiaohong Zhu¹  Haidee Cadd³  Scott Mooney¹ 

[1] Earth and Sustainability Science Research Centre, University of New South Wales;School of Geography and Environment, Jiang Xi Normal University;Chronos 14Carbon-Cycle Facility, University of New South Wales;School of Earth and Environmental Sciences, University of Wollongong

关键词: charcoal analysis;    wildfire;    FTIR spectroscopy;    Charring Intensity (CI);    Australia;    cultural burning;   

DOI  :  10.3390/fire6020054

学科分类：环境科学（综合）

来源: mdpi

【 摘 要 】

This study examined the effects of commonly used oxidants in sedimentary macroscopic charcoal analysis on two sediment cores from Thirlmere Lakes National Park, Southeast Australia. The cores, from Lake Werri Berri (WB3) and Lake Couridjah (LC2), span ~900 years and 135,000 years, respectively. The Charcoal Accumulation Rate (CHAR) for both charcoal area and count was quantified using four different chemical treatments and compared to a control using only water. We also quantified the Charring Intensity (CI) of isolated charcoal fragments, a proxy for the severity/intensity of fire, determined using the FTIR spectral characteristics of the remaining charcoal after each treatment. We found significant differences in both the area and number of particles across all treatments in both cores. Significantly, we found substantial differences in CI between treatments, with few charcoal particles formed in low-severity fire (e.g., below ~400 °C or 3.0 °C.s.106) in groups treated with an oxidant. In contrast, the control group displayed a wider range of CI values and contained lightly pyrolyzed particles. This suggests that methods using an oxidant to concentrate sedimentary charcoal are potentially biasing records towards high-intensity or -severity fires. We suggest that consideration should be used when choosing laboratory methods based on the hypotheses being tested.

【 授权许可】

CC BY