Post-Fire Carbon Dynamics in a UK Woodland: A Case Study from the Roaches Nature Reserve

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General comment:

The manuscript presents a timely and well-structured case study investigating the post-fire carbon dynamics in a temperate woodland in the UK. The authors employ a robust, multi-faceted methodology combining remote sensing, dendrochronology, and soil analysis to assess the ecological and economic impacts of a 2018 wildfire. The results are clearly presented and support the main conclusions regarding species-specific resilience and significant carbon sequestration loss.

Major Comments:

1. Clarity on Study Scope and Carbon Pools: The analysis focuses primarily on above-ground biomass carbon of trees and soil carbon at 5 cm depth. Important carbon pools such as below-ground root biomass, litter, coarse woody debris (from dead trees), and understory vegetation are acknowledged as excluded but not quantified or discussed in terms of their potential impact on the overall carbon balance. Given the high mortality of  decidua, the fate of the carbon in the dead biomass (whether it remains as a stock, decomposes, or was consumed by the fire) is a significant aspect of post-fire carbon dynamics. The authors should more explicitly state the limitations of their carbon stock assessment in the discussion and clarify that the "total carbon stock" refers specifically to living tree biomass and shallow soil carbon.
2. Justification of the CSL Index:The CSL index is a promising tool. However, its interpretation would be strengthened by a more detailed rationale. The index is calculated as 1 minus the ratio of CO₂ fixed in the burned area to that in the control area. This means it measures the relative loss compared to the control. While useful, this value is inherently influenced by the performance of the control site.  Please provide a brief discussion.
3. Contextualization of Economic Valuation: The economic valuation based on the EU carbon price (75€/tCO₂) is a valid approach. However, the discussion of the results would benefit from acknowledging the variability and policy-dependence of this price.

Minor Comments:

1. The abstract states that soil properties showed "no significant changes." Could this be phrased more precisely to specify which key properties were measured (e.g., SOC, microbial biomass) and at what depth, to avoid overgeneralization?
2. The introduction effectively sets the global context. However, for a UK-focused study, could it be strengthened by briefly citing specific UK-based studies or reports that highlight the increasing wildfire risk and its perceived impact on the country's limited forest resources?
3. Section 2.1: Could you provide more detail on the topography (e.g., slope, aspect) of the burned and control plots? As topography can influence fire behavior and post-fire recovery, was it considered in the site selection to ensure comparability?
4. Section 2.2: For the dNBR analysis, what specific thresholds (e.g., as suggested by the USGS) were used to classify fire severity levels (e.g., low, moderate, high)? Providing these would enhance the reproducibility of the methodology.
5. Section 2.4: The allometric equation for tree height uses parameters 'a' and 'b'. How were these parameters specifically derived? Were they calibrated using local data or taken as generalized values from the literature for European conifers? The sensitivity of the AGB estimates to these parameters could be notable.
6. Section 3.2: Figure 3A and 5A: The graphs show a notable increase in CO₂ fixation starting around the 1980s for both species. Can you speculate on the potential drivers (e.g., climate trends, stand maturation) in the figure caption or results section to aid interpretation before the discussion?
7. In the discussion and conclusion section, limitations and future development trends of this paper should be presented

Author Response

Reviewer 1

General comment:

The manuscript presents a timely and well-structured case study investigating the post-fire carbon dynamics in a temperate woodland in the UK. The authors employ a robust, multi-faceted methodology combining remote sensing, dendrochronology, and soil analysis to assess the ecological and economic impacts of a 2018 wildfire. The results are clearly presented and support the main conclusions regarding species-specific resilience and significant carbon sequestration loss.

We are grateful for the reviewer’s evaluation and constructive feedback. We have carefully addressed the raised points in order to further improve the quality of the manuscript.

Major Comments:

1. Clarity on Study Scope and Carbon Pools:The analysis focuses primarily on above-ground biomass carbon of treesand soil carbon at 5 cm depth. Important carbon pools such as below-ground root biomass, litter, coarse woody debris (from dead trees), and understory vegetation are acknowledged as excluded but not quantified or discussed in terms of their potential impact on the overall carbon balance. Given the high mortality of decidua, the fate of the carbon in the dead biomass (whether it remains as a stock, decomposes, or was consumed by the fire) is a significant aspect of post-fire carbon dynamics. The authors should more explicitly state the limitations of their carbon stock assessment in the discussion and clarify that the "total carbon stock" refers specifically to living tree biomass and shallow soil carbon.

We thank the Reviewer for the comment. The term “total carbon stock” has been replaced with “tree–soil carbon stock” in order to clarify that it includes only above-ground living biomass and shallow soil organic carbon (0–5 cm). In the Discussion, we expanded the text to highlight these limitations and to address the uncertainty concerning the fate of carbon in dead L. decidua (See Lines 457-473)

 

2. Justification of the CSL Index: The CSL index is a promising tool. However, its interpretation would be strengthened by a more detailed rationale. The index is calculated as 1 minus the ratio of CO₂ fixed in the burned area to that in the control area. This means it measures the relative loss compared to the control. While useful, this value is inherently influenced by the performance of the control site.  Please provide a brief discussion.

 

Thanks for the comment. In this new version of the manuscript, we clarified in both the Methods and the Discussion that the CSL index was intentionally designed as a relative metric, using the control as the best local reference to highlight the functional impairment of burned stands relative to the undisturbed sequestration potential (See Lines 253-256 and 466-470).

 

3. Contextualization of Economic Valuation: The economic valuation based on the EU carbon price (75€/tCO₂) is a valid approach. However, the discussion of the results would benefit from acknowledging the variability and policy-dependence of this price.

 

We agree with the Reviewer. In the Discussion, we now acknowledge that carbon credit prices are highly variable and policy-dependent, and we clarified that the reported monetary estimates represent only one possible scenario (See 450-452).

Minor Comments:

1. The abstract states that soil properties showed "no significant changes." Could this be phrased more precisely to specify which key properties were measured (e.g., SOC, microbial biomass) and at what depth, to avoid overgeneralization?

 

Done at Lines 19-20.

 

2. The introduction effectively sets the global context. However, for a UK-focused study, could it be strengthened by briefly citing specific UK-based studies or reports that highlight the increasing wildfire risk and its perceived impact on the country's limited forest resources?

 

We followed the suggestions adding Lines 77-80, where we have strengthened the wildfire issue, focusing on the UK.

 

3. Section 2.1: Could you provide more detail on the topography (e.g., slope, aspect) of the burned and control plots? As topography can influence fire behavior and post-fire recovery, was it considered in the site selection to ensure comparability?

 

Thank you for having highlighted that. Although these details are specified in ref 41 as reported at Line 151, we have added, according to the Reviewer’s comment, Lines 169-170.

 

4. Section 2.2: For the dNBR analysis, what specific thresholds (e.g., as suggested by the USGS) were used to classify fire severity levels (e.g., low, moderate, high)? Providing these would enhance the reproducibility of the methodology.

 

Thank for having highlighted this important missing information, we have fixed accordingly at Line 154.

 

5. Section 2.4: The allometric equation for tree height uses parameters 'a' and 'b'. How were these parameters specifically derived? Were they calibrated using local data or taken as generalized values from the literature for European conifers? The sensitivity of the AGB estimates to these parameters could be notable.

 

We thank the Reviewer for this useful comment. In the revised manuscript, we have clarified how the parameters were derived: a was locally calibrated for each tree using field measurements from 2023, while b was adopted from mean values reported in the literature for temperate European conifers. This ensures that the model is both anchored to local data and consistent with established allometric relationships (Lines 198-207).

 

6. Section 3.2: Figure 3A and 5A: The graphs show a notable increase in CO₂ fixation starting around the 1980s for both species. Can you speculate on the potential drivers (e.g., climate trends, stand maturation) in the figure caption or results section to aid interpretation before the discussion?

 

We thank the Reviewer for the suggestion. We have added this consideration in the Results section to highlight the increase in CO₂ fixation from the 1980s (Lines 303-305, 333-335) and expanded the Discussion to include further possible drivers such as past management activities (Lines 431-432).

 

7. In the discussion and conclusion section, limitations and future development trends of this paper should be presented

 

We thank the Reviewer for the suggestion. In the revised version of the manuscript, we have addressed the main limitations related to carbon stock estimation (in line with the previous comment) and included sentences to possible future developments concerning the site and carbon outcomes, both in the Discussion and in the Conclusions sections (Lines 489-509 and 524-527).

 

Reviewer 2 Report

Comments and Suggestions for Authors

The article presents the results of research on fire resistance dynamics in a case study for The Roaches nature reserve.

Abstract

The abstract presents the rationale for the research well. The method of forest assessment is indicated, but the tools for its use are not specified.

The basic results of research on the resistance of L. decidua and P. sylvestris to the effects of fire are presented.

The decline in CO2 sequestration is indicated, but without providing values or differences in the species studied.

Keywords

No species specified: L. decidua and P. sylvestris

Introduction

A review of the literature confirming the impact of environmental changes on forest functioning is presented.

Fire factors threatening European forests were confirmed. A decline in forest resilience as a result of climate change and increasing fire risks was indicated.

The introduction does not contain a defined research objective or research hypothesis.

Materials and methods

The post-fire and reference study areas were well defined.

Data on the complex and the impact of fire on forest regeneration were presented.

The satellite analyses and the method of calculating the indicators, together with the software used, were indicated.

The methods were well supported by scientific literature.

The method of assessing CO2 sequestration loss and soil testing was provided.

Results

The results present an assessment of the level of CO2 sequestration for the studied areas with L. decidua and P. sylvestris stands.

The graphs are clear and well described.

Discussion

The discussion presents the research results well. Links to the literature are indicated.

There is no indication of the value of the compared research items and those obtained in the literature.

There is no assessment of the extent of damage and losses to the ecosystem. No reference is made to indicators of forest resilience and functional potential.

The authors have defined the impact of fires on forest land in more detail. The level of change is given in relation to the literature and other cases after fires.

Conclusions

 The conclusions correspond to the research results.

There is no basis for economic analysis of the ability of trees to absorb CO₂. Such values were not presented.

No values indicating the loss of ecosystem services were provided.

No statistics on the research results were provided.

Literature.

The literature was selected correctly.

Author Response

Reviewer 2

General comment:

The article presents the results of research on fire resistance dynamics in a case study for The Roaches nature reserve.

 

We thank the Reviewer for the suggestions and comments, we have addressed the raised points to reach higher quality for the manuscript.

Abstract

The abstract presents the rationale for the research well. The method of forest assessment is indicated, but the tools for its use are not specified.

 

Done at Lines 15-17.

 

The basic results of research on the resistance of L. decidua and P. sylvestris to the effects of fire are presented.

 

We thank the Reviewer for the comment.

 

The decline in CO2 sequestration is indicated, but without providing values or differences in the species studied.

 

Done at Lines 21-24.

 

Keywords

No species specified: L. decidua and P. sylvestris

 

Done. We added the suggested keywords.

 

Introduction

A review of the literature confirming the impact of environmental changes on forest functioning is presented.

Fire factors threatening European forests were confirmed. A decline in forest resilience as a result of climate change and increasing fire risks was indicated.

 

We would like to thank the Reviewer for having positively assessed the Introduction section.

 

The introduction does not contain a defined research objective or research hypothesis.

 

The research objective and working hypotheses are reported from Lines 98-107. However, we have rephrased them for greater clarity.

Materials and methods

The post-fire and reference study areas were well defined.

Data on the complex and the impact of fire on forest regeneration were presented.

The satellite analyses and the method of calculating the indicators, together with the software used, were indicated.

The methods were well supported by scientific literature.

The method of assessing CO2 sequestration loss and soil testing was provided.

 

We really appreciate all the Reviewer’s positive feedback.

 

Results

The results present an assessment of the level of CO2 sequestration for the studied areas with L. decidua and P. sylvestris stands.

The graphs are clear and well described.

 

We thank the Reviewer for the positive evaluation.

Discussion

The discussion presents the research results well. Links to the literature are indicated.

 

We thank the Reviewer for the assessment.

 

There is no indication of the value of the compared research items and those obtained in the literature.

 

Done at Lines 483-485.

 

There is no assessment of the extent of damage and losses to the ecosystem. No reference is made to indicators of forest resilience and functional potential.

 

We kindly invite the Reviewer to look at Lines 128-131, 284-292, and 426-442 to review the wildfire damage extension and the economic value of the carbon sequestration loss, which is a proxy for assessment of the losses to the ecosystem as well as forest resilience and functional potential.

 

The authors have defined the impact of fires on forest land in more detail. The level of change is given in relation to the literature and other cases after fires.

 

We thank the Reviewer for the comments.

 

Conclusions

The conclusions correspond to the research results.

There is no basis for economic analysis of the ability of trees to absorb CO₂. Such values were not presented.

No values indicating the loss of ecosystem services were provided.

No statistics on the research results were provided.

 

In this new version of the manuscript, the conclusions have been revised based on the comments above.

 

Literature.

The literature was selected correctly.

 

We appreciated the Reviewer’s comment.