Aboveground Biomass Mapping and Fire Potential Severity Assessment: A Case Study for Eucalypts and Shrubland Areas in the Central Inland Region of Portugal

Round 1

Reviewer 1 Report

The paper titled "Aboveground Biomass Mapping and Fire Potential Severity Assessment: A Case Study for Eucalypts and Shrubland Areas in the Centre Inland of Portugal" presents a comprehensive investigation into the use of NDVI for mapping aboveground biomass (AGB) and assessing fire potential severity in eucalypts and shrubland areas. The study's objectives are well-defined and aligned with the importance of managing forest resources and mitigating fire hazards. The methodology is robust, combining field data collection, satellite imagery analysis, and statistical modeling to achieve its goals.

The paper offers significant strengths that enhance its contribution to the field:

• The research objective is clear and relevant to the management of forest ecosystems and fire risk.
• The methodology is adequately detailed, reflecting a systematic approach to data collection, processing, and analysis.
• The presentation of results through tables and figures is informative and coherent.

However, to strengthen the paper's overall impact and clarity, there are several areas that warrant minor revisions:

 

• The abstract could benefit from clearer phrasing of the study's objectives. For instance, instead of "This study aims were the following," it could be rephrased as "The objectives of this study were as follows.
• There's a mix of verb tenses in the manuscript. For consistency, it's recommended to use the past tense when discussing actions and results that have already been completed, and the present tense when discussing general truths or conclusions drawn from the study. For example, "Despite of field data collection being the most accurate technique..." should be corrected to "Despite field data collection being the most accurate technique..."
• Some statements, such as "According to the last National Forest Inventory (NFI 2015)..." could benefit from more direct attribution, such as including the name of the source within the sentence.
• While the references provided give a foundational understanding, consider incorporating more recent research (if available) that might have contributed to the advancements in the field or related methodologies.
• The rationale behind selecting 30 field sample points for both eucalypts and shrubland areas could be further elaborated. How representative are these points of the entire study area? Are there potential biases introduced due to this selection?
• While the individual tree biomass prediction equations for eucalypts and shrubland are provided, a brief explanation of how these equations were developed or chosen could be included. what were the main sources of data or methodologies used to derive them?
• The legend for “hdom” is missing from the legend in Table 4.
• While the statistical measures for model validation are listed, it would be beneficial to discuss the limitations of using these measures. For example, R-squared (R2) alone might not be the most suitable metric for assessing model performance, especially in cases where the relationship between variables might be complex. Consider mentioning the potential weaknesses of these measures and discussing additional validation techniques that might enhance the accuracy of the models.
• The section on NDVI interpretation provides a general overview of how NDVI values correspond to different land covers, but it might be helpful to provide specific ranges of NDVI values that are commonly associated with healthy eucalyptus and shrubland vegetation. This could provide readers with a better understanding of what the NDVI values mean in the context of your study.
• While climatological data from the local station is used for temperature and precipitation analysis, it could be helpful to briefly discuss how this data contributes to the research. For instance, does this data help contextualize the AGB estimation, or does it aid in understanding the potential influences of climatic conditions on vegetation patterns?
• When discussing the impact of species phenology on NDVI trends, you could provide more detailed explanations of how different phenological stages might affect NDVI values. This could add depth to your interpretation.
• If applicable, you could include information about the statistical significance of your results, especially when comparing AGB estimates and NDVI values. This adds a layer of confidence to your findings.
• Discussion: While discussing the results, consider addressing potential confounding variables and limitations that may affect the accuracy of NDVI-based AGB mapping. Discuss the broader implications of the findings beyond fire hazard mitigation.
• Conclusion: Emphasize how the AGB maps can be effectively integrated into fire hazard models to provide real-time fire severity assessment. Highlight any remaining research gaps that could be addressed in future studies.
• In your conclusion, re-emphasize the most critical implications of your study. What are the practical takeaways for forest management and fire mitigation strategies? Clearly outline the value that your AGB maps bring to these areas.

The paper generally uses English proficiently, although there are a few instances of grammatical and punctuation errors that could be improved. To enhance the clarity and coherence of the language, it's important to maintain consistent verb tenses and structure sentences more effectively. Some sentences might flow better with a little restructuring, making the paper easier to read. Additionally, certain phrases and word choices could be refined for greater precision and clarity.

Author Response

Please, see the file in attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

I have now completer the review of the article entitled “Aboveground biomass mapping and fire potential severity assessment: A case study for eucalypts and shrubland areas in the Centre Inland of Portugal”. In similar studies, the ground-checking procedure is essential and it must be highlighted throughout the text. Hence, according to my opinion, studies including both remote sensing and field measurements are welcome. In general terms, the article is good, well-written, and well-structured. However, from my side, I have to refer to a significant issue that is subject to major revisions.

-        In the title page and the main text as well, the term “fire severity” is used. As to my knowledge, this term is associated with potential fire behavior and, consequently, with some critical characteristics of the flaming front such as (Byram’s) fireline intensity, rate of spread, and flame length. Those are determined by a combination of the fine fuel load, moisture, wind, topography, temperature, etc. In the current study, the AGB is solely used at spatial basis in order to reflect fire severity, which is not accurate in a frame of scientific article. In fire science, the available (fine) fuel load for combustion is used and I strongly suggest the author, revise the manuscript taking into consideration this shortage. Since allometric models are currently used to estimate fuel loads, the fuel distribution will remain the same but the loads will be significantly reduced. If the author wishes to avoid those significant changes I suggest revising the ms by referring to a wider forest management framework, including fire reduction hazard aspects through fuel modifications. Perhaps, the “fire potential severity assessment” could be preferably reflected through the implementation of fire simulations (Flammap, FARSITE etc.), but I believe that this is out of the scope of the current article.

Secondary issues       

-        I suggest the author explain briefly the estimation of both, dominant height and diameter. As I can see, it is a basic input in Tomé et al. (2007) models.  

-        L221-222 What models are mentioned in those lines? Perhaps the models (a) and (b) in Figure 9. If so, why the intercept is missing?   

Author Response

Please, see the file in attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The author introduced an alternative method to verify the wildfire severity and the manuscript has been significantly improved. Now it is a strong submission and deserves publishing.

Author Response

Dear Reviewer 2

Thank you so much for your comments and suggestions to improve the manuscript.

Regards
Castelo Branco, 30 August 2023
Cristina Alegria