Carbon Footprint Variability in Engineered Wood Products for Timber Buildings: A Systematic Review of Carbon Accounting Methodologies

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper provides a review of carbon accounting methodologies for engineered wood products (EWPs) and timber buildings. The research work is interesting. Generally, this paper is a well-structured and informative review that significantly contributes to the understanding of carbon accounting for timber products. However, the authors are invited to respond the following comments before it can be recommended for publication.

1. While the paper thoroughly summarizes findings, it could benefit from deeper critical analysis. For example, it could discuss why certain methodologies (e.g., Tier 2 IPCC) dominate despite their limitations.
2. The review acknowledges variability in results,but it does not sufficiently address the root causes, such as data gaps or inconsistencies in LCA databases?
3. The review notes that Europe and North America dominate the literature, but it does not explore how this bias might affect global applicability. More discussion on underrepresented regions (e.g., Africa, South America) would be valuable.
4.  It is suggested to include a section analyzing why certain methodologies are preferred and how their limitations impact carbon accounting outcomes.

Author Response

Please refer to attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

• The manuscript lacks new, innovative metrics for emission reduction regarding engineered wood products. Please add specific quantitative indicators and emission reduction metrics related to EWPs in both the abstract and conclusion.
• While the manuscript presents a survey of carbon emissions over the past decades, it does not sufficiently present the authors' original findings.
• The manuscript does not adequately discuss the research background, engineering application value, suitability, and limitations of the study. It is suggested that the authors add a dedicated section to clearly outline these aspects.
• Figure 1 is overly complex. Please simplify the figure and better reflect the carbonation evolution process in the text. The description within the figure should be simplified to improve clarity and ensure that the key points are communicated effectively.
• The manuscript includes basic theoretical formulas, but their physical meanings are not adequately explained.
• Figure 4 presents key data, but it lacks a corresponding quantitative modeling formula. It is recommended that the authors provide a well-defined equation or model that represents the relationships illustrated in Figure 4.
• Figures 10 and 11 analyze carbon footprints, but they lack a comprehensive quantitative analysis. The authors should provide detailed calculations, error analysis, and possible correlations between the carbon footprint data and different variables.
• Figure 14 predominantly discusses past research but lacks original quantitative analysis from the authors. It is suggested that the authors develop an innovative, model-based analysis that quantifies their findings.
• The abstract should be refined to show the primary conclusion of this study. It is suggested to emphasize the research focus of the paper, such as research background, research purpose, research methods, main research work, engineering application significance, etc.
• In the introduction section, the author should further highlight the shortage of the previous investigation and the innovation of this study, which is important for a scientific paper.
• The Introduction lacks an in-depth review and evaluation of green sustainable materials, particularly regarding material performance and structural performance. Given the engineering application focus of this research, the manuscript should include recent literature and detailed discussions on material and structural properties. It is recommended to supplement the manuscript with the following articles: (a) New insights into the effects of silicate modulus, alkali content and modification on multi-properties of recycled brick powder-based geopolymer. (b) Stiffness degradation and mechanical behavior of microfiber-modified high-toughness recycled aggregate concrete under constant load cycling.
• The paper lacks a section on the significance of the study, which should be supplemented.
• There is a lack of analysis on the characterization information of the internal microstructure of materials, SEM, This is only a surface analysis, it is recommended to supplement the internal structure analysis of CT.
• The conclusions need to be refined and improved. The innovative work and main findings of this study should be emphasized in the conclusions. Avoid including excessive details and preferably express the points using numbering, such as 1), 2), 3), etc. It is advisable to limit the conclusions to no more than four concise statements.
• The manuscript lacks a dedicated discussion section addressing the engineering background, practical value, applicability, and limitations of the study.
• Furthermore, both the abstract and conclusion sections fail to provide quantitative performance indicators or model-based findings, which are essential for demonstrating the significance and reliability of the results.

 

Author Response

Please refer to attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. The article has a clear focus and systematically reviews carbon accounting methodologies for engineered wood products (EWPs) and timber buildings. However, it lacks an in-depth explanation of the principles and applications of the discussed methods. A more thorough comparative analysis of the key methodologies is recommended.
2. Although a large number of references are covered, the analysis of regional differences in carbon emissions remains superficial. The discussion should delve deeper into the specific characteristics of each region and how they influence the results.
3. The research methodology is clearly presented, and the criteria for literature selection are well-defined. However, it is advisable to further clarify the specific steps of the systematic review (e.g., the rationale for keyword selection, and the inclusion/exclusion criteria for literature).
4. The article is well-structured overall, but some figures and tables lack clarity in their labels (such as figure titles and axis units). It is suggested to provide more detailed explanations to enhance readability and professionalism.
5. The overall language is relatively fluent, but there are minor grammatical issues in some sentences. Further proofreading is needed to improve the accuracy and fluency of the English expression.
6. The references are rich and diverse, but the formatting should be standardized, especially regarding publication year, author names, and journal titles. Additionally, some references are outdated; more recent literature should be cited.

Author Response

Please refer to the attached file.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Very well written and profound work on the current state of caarbon accounting methodologies and applications for EWPs and timber buildings, focusing on the producction state. As per the authors suggestions the reclaimed timber usage may reduce the global warming potential by upto 92%. This idicates a very huge marginal change and hence authors should focus on the adoption level and policy making in near future. 

Author Response

1. Summary

Thank you very much for your positive and supportive comments. We are pleased to hear that you found the manuscript well written and the analysis meaningful. We have considered your suggestion carefully and revised the manuscript to address it.

2. Point-by-point response to Comments and Suggestions for Authors

Comments 1:

Very well written and profound work on the current state of carbon accounting methodologies and applications for EWPs and timber buildings, focusing on the production state. As per the authors suggestions the reclaimed timber usage may reduce the global warming potential by up to 92%. This indicates a very huge marginal change and hence authors should focus on the adoption level and policy making in near future.

Response 1:

Thank you for your kind feedback and constructive suggestion. We agree that reclaimed timber offers substantial emissions reduction potential. In response, we have expanded Section 5.6 (Limitations and Future Research Directions) (Page 26, line 944-987) to include a specific point on the underutilisation of reclaimed timber and the barriers to its adoption. We highlight the need for supportive policy frameworks, procurement guidelines, and circular design practices to promote reuse and material recovery. This addition aims to strengthen the study’s relevance for decision-makers and future research on sustainable timber construction.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The format of the manuscript requires further adjustments following the journal's specifications. This may include adjustments to font size, line spacing, citation format, etc., to ensure the submission fully meets the journal's guidelines.

Author Response

Comment 1:

The format of the manuscript requires further adjustments following the journal's specifications. This may include adjustments to font size, line spacing, citation format, etc., to ensure the submission fully meets the journal's guidelines.

Response 1:

We thank the reviewer for the helpful feedback regarding manuscript formatting. In this second revision, we have thoroughly reviewed the document and made the following updates to ensure full compliance with MDPI’s formatting requirements, specifically:

1): We updated the entire manuscript using journal given template, including revisions to the font and line spacing;

2) We checked that all figures and tables are cited and cross-referenced appropriately in the main text. All captions were revised to follow the journal style;

3): We thoroughly reviewed all in-text citations and revised them to follow MDPI’s numerical citation style. All author–year references were removed to ensure consistency;

4): We reformatted the entire reference list ;

5): We added detailed reference entries for all international standards cited in the manuscript, including ISO 14040, ISO 14044, PAS 2050, ISO 14067, ISO 14064-1, GHG Protocols, and IPCC Guidelines. These were formatted using the required structure (Standard’s Number; Title. Publisher: City, Country, Year) and cited in the main text (Please see references [29]–[38], [56], and [60]).