the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 12 Aug 2025
The charcoal morphology of different vegetation types in the wildfire
Abstract. Wildfires are a crucial element in the earth's ecosystem, playing a significant role in maintaining ecological balance. Charcoal, a key product of fires, can be examined for its morphological traits to distinguish between various fuel sources. This analysis helps in understanding the relationship between regional vegetation environments and fire dynamics. However, current research on charcoal morphology heavily relies on simulation experiments, lacking real-world data from natural wildfires. This study delves into the morphological characteristics of charcoal formed under wildfire conditions by investigating samples from four distinct vegetation types. By sidestepping the uncertainties of simulation experiments, the research uncovers intriguing patterns. The findings indicate a gradual decrease in charcoal size across different ecosystems, such as evergreen coniferous forests, warm-humid herbs, evergreen broad-leaf forests, and grasslands. The length-to-width (L/W) ratio of charcoal alone is insufficient for classifying fuel types accurately. To address this issue, a decision tree model was crafted to effectively categorize various charcoal types, achieving an impressive accuracy rate of 72.44 %. This paper presents a thorough examination of charcoal morphology within diverse vegetation landscapes, offering valuable insights for fuel type identification based on charcoal characteristics. Ultimately, this research contributes to enhancing our knowledge of the intricate interactions between natural wildfires and vegetation dynamics.
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Status: final response (author comments only)
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RC1: 'Comment on egusphere-2025-3665', Anonymous Referee #1, 08 Sep 2025
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AC2: 'Reply on RC1', shurong zhang, 29 Sep 2025
Dear Sir/Madam,
Thank you for taking the time to review our manuscript. We appreciate the clear and constructive comments of the reviewer and think that the suggested changes will improve the manuscript. Please find our answers in the attached PDF file.
Sincerely,
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AC2: 'Reply on RC1', shurong zhang, 29 Sep 2025
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RC2: 'Comment on egusphere-2025-3665', Anonymous Referee #2, 09 Sep 2025
General Comments:
Zhang et al. present morphometric data of sedimentary charcoal and relate these data to their inferred fuel source. They conclude that L:W values insufficiently characterize fuel types and also present a decision tree model which boasts >72% accuracy.
However, this paper and this study is deeply flawed. The paper’s conclusions are not supported by the data, are poorly-founded in the literature, and overstep or overgeneralize the usefulness of their analyses. For example, the inherent assumption of their approach is that the fuel sources of charcoal are known, which the authors themselves reveal to be untrue. Similarly, The authors justify their study by identifying a gap/oversight in the literature… which is actually untrue. Further, the authors make numerous false and misleading statements about the published literature, as well as their own research (which contains many assumptions and poorly founded rationales). The manuscript/study is poorly justified and does not contribute meaningfully to the published literature because it seems to disregard much of the relevant context while also asserting non-existent or ungrounded knowledge gaps. This manuscript would introduce confusion and misleading information into the literature.
Overall, I recommend that this manuscript be rejected outright. Although there is doubtless value to the analyses conducted by the authors, their framing and presentation are beyond revision and require an entirely new manuscript to present these analyses.
Specific Comments:
L47: “simulation experiments” implies computational modelling. I don’t think this is appropriate phrasing.
L51-53: This sentence doesn’t make sense. What defines the gradient of these ecosystems? Or is this simply the order of the decrease?
L109: Researchers?
L111-131: I would say that this is a rather incomplete and dated summary of the use of L:W as a fuel type proxy. Further, many of the details provided in this text are broadly irrelevant to the point of the text (i.e. no need to provide specified charcoal sizes).
L132-135: This is not a convincing basis. The laboratory experiments provide reliable insights when applied to sediment data (i.e. as shown through comparisons to other proxies like pollen and phytoliths). To simply say they are unrealistic is an oversimplification. Additionally, much work has meticulously cataloged plant taxa and their resulting charcoal, so to say there is “a gap in systematic research” is very narrow-minded and overlooks the efforts of numerous research teams.
L135-139: This is simply incorrect. There is not a debate regarding L:W and its validity. The authors cannot state this without providing supporting references. Further, efforts have identified clear and explicit threshold values numerous times so this is simply incorrect (see Vachula et al. 2021, Feurdean et al. 2021, Feurdean et al. 2023).
L132-152: This entire block of text lacks references, a clear indicator that this text is not well-supported by nor derived from the published literature.
L155-158: This would mean that the direct fuel type sources of the charcoal samples are not known or constrained. The assignment of the fuel source is thereby ambiguous whereas it is presented as fact. This is misleading.
L159: To my knowledge, all published literature analyzing charcoal morphologies for the purposed of fuel type reconstructions has focused on macroscopic charcoal, not microscopic charcoal. This difference must be made clearer, as it has implications for the validity of the analysis (i.e. Inoue et al. 2025).
L193-195: This represents circular reasoning. Fuel type attribution to charcoal cannot be made by assuming fuel types.
L196-197: This is not supported by nor shown by the analyses of the authors.
L200-224: See previous two comments.
L229-278: Throughout this text, the taxa sources of charcoal are assumed yet they are not directly known. This is very misleading.
L229-278: Further, the intendent length and width of charcoal particles is not a common proxy so it is unclear why they are measured and presented here.
L332-335: This is simply untrue and not supported by the references cited.
L335-338: This is simply untrue and not supported by the references cited.
L342-345: This is not supported by these references.
L368-378: This texts seems only tangentially related to the analyses at hand.
L383-386: This conclusion is not supported by the data collected by the authors.
L394-416: This text assumes reliable assignment of the fuel source to the charcoal, which is entirely lacking.
L417-419: This is entirely at odds with the premise constructed in the introduction (L135-139).
L421: These values are directly in line with those that would be expected from published literature. There is not a discrepancy (as is stated in L424).
L428-429: But they are not actually different.
Citation: https://doi.org/10.5194/egusphere-2025-3665-RC2 -
AC1: 'Reply on RC2', shurong zhang, 29 Sep 2025
Dear Sir/Madam,
Thank you for taking the time to review our manuscript. We tried to do our best for all the suggestions. According to your comments, you can find the point-to-point replies below.
Sincerely,
General Comments:
R: Thank you for these comments. This study collected charcoal samples from natural wildfires with documented fuel types. By synthesizing findings from previous researches, we systematically characterized the morphological features of charcoal across different vegetation types. The statements regarding published literatures and the analysis in the discussion section have been refined in the new manuscript.
Specific comments:
L47:” simulation experiments” implies computational modelling. I don’t think this is appropriate phrasing”
R: Thank you for pointing this. We share your view that simulation experiments do not imply computational modeling.
L51-53:” This sentence doesn’t make sense. What defines the gradient of these ecosystems? Or is this simply the order of the decrease?”
R: Yes, it is just the order of the decrease. And we will clarify this in the revised manuscript.
L109:” Researchers?”
R: Thanks, this sentence means that the number of studies in this field is increasing.
L111-131:” I would say that this is a rather incomplete and dated summary of the use of L/W as a fuel type proxy. Further, many of the details provided in this text are broadly irrelevant to the point of the text (i.e. no need to provide specified charcoal sizes).”
R: Thank you for the helpful suggestions. We will rephrase this part.
L132-135:” This is not a convincing basis. The laboratory experiments provide reliable insights when applied to sediment data (i.e. as shown through comparisons to other proxies like pollen and phytoliths). To simply say they are unrealistic is an oversimplification. Additionally, much work has meticulously cataloged plant taxa and their resulting charcoal, so to say there is “a gap in systematic research” is very narrow-minded and overlooks the efforts of numerous research teams.”
R: Thank you for pointing this. We will rephrase according to your suggestions. And we aim to convey that simulation experiments cannot fully the complex conditions of real wildfires, and that charcoal collected from wildfire consists of an assemblage from various plant species, rather than deriving from a single plant source. It is important to note that the limited number of studies in this area does not imply a disregard for the findings of other research teams.
L135-139:” This is simply incorrect. There is not a debate regarding L:W and its validity. The authors cannot state this without providing supporting references. Further, efforts have identified clear and explicit threshold values numerous times so this is simply incorrect (see Vachula et al. 2021, Feurdean et al. 2021, Feurdean et al. 2023).”
R: Thank you for pointing this. We will rephrase according to your suggestions in the revised manuscript.
L132-152:” This entire block of text lacks references, a clear indicator that this text is not well-supported by nor derived from the published literature.”
R: Thanks, we have cited numerous references in the previous sections, this part aims to summarize the existing research gaps and provide an introduction to the present study.
L155-158:” This would mean that the direct fuel type sources of the charcoal samples are not known or constrained. The assignment of the fuel source is thereby ambiguous whereas it is presented as fact. This is misleading.”
R: Thanks, the fuel sources for our charcoal samples are clearly identified and known, as provided in the table 1. This study investigates charcoal from different vegetation types based on these known fuel sources.
L159:” To my knowledge, all published literature analyzing charcoal morphologies for the purposed of fuel type reconstructions has focused on macroscopic charcoal, not microscopic charcoal. This difference must be made clearer, as it has implications for the validity of the analysis (i.e. Inoue et al. 2025).”
R: Thank you for pointing this. Now, a number of current studies utilize the morphology of charcoal to infer vegetation type (Feurdean et al.,2021,2023; Pereboom et al.,2020) and they were mentioned in the introduction.
L193-195:” This represents circular reasoning. Fuel type attribution to charcoal cannot be made by assuming fuel types.”
R: Thanks, this section is limited to describing the types of fuel, rather than making assumptions about them. These statements are based on filed observations from unburned areas within the sampling region.
L196-197:” This is not supported by nor shown by the analyses of the authors. “
R: Thanks, this sentence serves to describe the results of vegetation combustion, not to analyze them The analysis is provided in the discussion section.
L200-224:” See previous two comments.”
R: Thanks, this section is limited to describing the types of fuel, rather than making assumptions about them. These statements are based on filed observations from unburned areas within the sampling region.
L229-278:” Throughout this text, the taxa sources of charcoal are assumed yet they are not directly known. This is very misleading.”
R: Thank you for pointing this. The fuel sources of our charcoal samples are clearly identified and known, as provided in the table 1.
L229-278:” Further, the intendent length and width of charcoal particles is not a common proxy so it is unclear why they are measured and presented here.”
R: Thanks, we aim to investigate the contribution of various charcoal morphological parameters in distinguishing between different fuel vegetation types.
L332-335:” This is simply untrue and not supported by the references cited.”
R: Thank you for the comment. This part wants to show that the morphological characteristics of charcoal reflect the vegetation assemblage rather than a single plant species. A great diversity of vegetation types provides more combustible biomass, which affects both the diversity of charcoal morphologies and the charcoal yield. This sentence will be rephrased and we will provide more references to support.
L335-338:” This is simply untrue and not supported by the references cited.”
R: Thanks, we aim to convey that the morphology of charcoal burning from natural wildfire is influenced by a multitude of factors, including tempertature, the degree of charcoalification and other. We will provide more references to support that.
L342-345:” This is not supported by these references.”
R: Thank you for pointing this, we will incorporate additional references.
L368-378:” This text seems only tangentially related to the analyses at hand.”
R: Thanks, we consider it necessary to include this text because it explains the underlying causes of the discrepancy.
L383-386:” This conclusion is not supported by the data collected by the authors.”
R: Thank you for this remark. We will clarify in the revised manuscript.
L394-416:” This text assumzes reliable assignment of the fuel source to the charcoal, which is entirely lacking.”
R: Thanks, we refer you to our earlier response on this matter for a detailed answer.
L417-419:” This is entirely at odds with the premise constructed in the introduction (L135-139).”
R: Thank you for highlighting this. The perspective that the L/W effrctively differentiates vegetation types stems primarily from simulation studies. This paper aims to explore these findings using charcoal from natural wildfires, an approach that builds upon the foundation laid in the introduction.
L421:” These values are directly in line with those that would be expected from published literature. There is not a discrepancy (as is stated in L424).”
R: Thank you for this comment. This study analyzed the L/W of charcoal from different vegetation types and found the differences to be minimal. This finding led to the conclusion that the L/W has limited diagnostic value, a conclusion based on our own observations as opposed to a comparison with existing data.
L428-429:” But they are not actually different.”
R: Thank you for pointing this. The term “difference” here refers to the discrepancy between our finding that L/W variations among vegetation types in this study are minimal, and the results of previous studies. It does not refer to the magnitude of the numerical values themselves.
Citation: https://doi.org/10.5194/egusphere-2025-3665-AC1
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AC1: 'Reply on RC2', shurong zhang, 29 Sep 2025
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