Carbon Sequestration and Landscape Influences in Urban Greenspace Coverage Variability: A High-Resolution Remote Sensing Study in Luohe, China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

It is critical to understand the roles of urban green spaces in carbon sequestration. The present study explores the potential of urban green spaces in central plains region in China for carbon sequestration. The study is well conducted and can be considered for publication if it can address the following issues:

 

Although you mention that you conducted field surveys according to the i-Tree-Eco I don’t find the steps on how you performed the model. Please give detailed methods on how this was done. Also, how was landscape metrics calculated and how was remotely sensed images utilised for modelling. Also please provide a section for data analysis as many analyses conducted is not comprehensible.

 

Figure 1: Please explain what is the source of the image (whether UAV or satellite). Also, mention which bands were used. Also, please make the image a bit bigger.

 

L 112-113- How was the image date chosen? What is the season of the image?

 

L 116- What were the wavelengths of these channels? Also, what were the resolution of UAV channels?

 

L 119- In the equations, please expand all abbreviations. You have not mentioned expansions of these indices anywhere else.

 

L 143- Give reference for Nowak.

 

L 219-landsat is mentioned first in the document. Why?

 

 

L 221- Figure 4?

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper addresses the topic of carbon sequestration, which is currently a highly significant and relevant area of research. The authors investigate the impact of various landscape indicators that define urban environments in relation to urban greenery and its influence on the effectiveness of the sequestration process. The paper focuses on the Chinese city of Luohe, thereby contributing to the existing body of knowledge regarding the ecosystem services provided by urban greenery. Moreover, it provides a foundation for comparison with other regions and proposes strategies for enhancing carbon sequestration. The methodology is presented in a clear manner; however, further elucidation is required in certain instances. Further detailed comments are provided below.

- line 39 why 'forest cities', not  'city forests'?

- lines 45-60: please provide an explanation of the mechanism by which carbon dioxide is more effectively sequestered in urban areas.

- equations 1-7: please provide a brief description of the indicators used.

- please expand the section on the methodology of carbon sequestration estimation, including the model, algorithms, and equations used.

- a description of all symbols and abbreviations used (e.g. GF-2, VIs) should be provided.

- lines 193 and subsequent: please provide the English names of the species.

- line 221: please note that this should be Figure 5, not Figure 4.

- lines 271-272: please refer to Figure 8.

- line 291: please use the term 'medium rate' instead of 'rate'. 

The research presented in the discussion section is limited to Chinese cities. Are these results similar worldwide? Perhaps a comparison could be made to another cities with a similar climate, not necessarily in China.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript entitled “Carbon sequestration and landscape influences in urban greenspace coverage variability: a high-resolution remote sensing study in Luohe, China” addresses a current and interesting problem of carbon sequestration for cities. The article should be improved to be well received by other scientists. The article is not structured in accordance with the guide for authors. In its current form, it is not suitable for publication. The authors should work on it with the methodology and statement of the aim and conclusions.

 

Comments:

1. The abstract should include the article's aim, a brief description of the research method, and the obtained results. The abstract should be improved to include all elements that allow for increasing the impact factor and readability of this article.

 

2. The introduction should include a presentation of the research problem, not a comparison of the Chinese and American economies - because this is not the research subject.

 

3. The state of research is not completed by defining the boundaries of the research gap.

 

3. There is a lack of a description of the research method and the possibility of replication of the research by other researchers, which is the basis of open science.

4. The selection of literature presenting the latest research in this research area is outdated.

 

5. The entire conclusions section is missing. The implications will not replace the conclusions, i.e. the generalized results of the research that the Authors conducted. The lack of conclusions is the result of the lack of a clearly formulated goal of the article - that is where you have to start.

 

6. It is not known whether the research presented in this article achieved the goal, because it was not specified.

 

7. The article is not suitable for publication in its current form.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Estimating carbon sequestration by urban tree is an important topic, particularly in the context of climate change mitigation efforts. While the concept and methodology of this research are not novel, certain methodological approaches are valuable. Overall, the study enhances our understanding of how field surveys, landscape indicators, and remote sensing data can be utilized to assess urban trees' capacity for carbon sequestration. The authors provide a clear and detailed description of the numerous steps required for data evaluation, and the manuscript is well-written and illustrated. Given its subject matter, methodology, and results obtained the study corresponds to the scope of the Forests journal.

However, upon reviewing the manuscript, I have identified numerous questions and concerns, indicating that the paper requires improvement. It is unclear why the authors include a variety of vegetation indices in their estimates when many studies have confirmed the significance of only a few of them for assessing forest biomass and carbon. A more thorough explanation is required regarding how the i-Tree package estimates carbon sequestration by trees. Additionally, the positioning of certain figures within the text requires further structuring to improve the overall organization and readability of the manuscript.

Other comments, suggestions:

Introduction. Including additional references from various regions worldwide would be beneficial for discussing the issues related to carbon sequestration and urban forests.

39-42 References needed. 

56-61 I recommend adding some references here.

69-74 Rewording or merging these two sentences could enhance this part of the section.

77-96 I recommend adding some references here.

78 -77 …. located in Central-South of Henan Province (Figure 1).

119-120 Why to use so many VI’s? Many studies have confirmed the acceptability of only a few of them in biomass/carbon estimates. For example, NDVI and EVI.

126 Reference

 143 … as recommended by Novak (reference)

124   2.3. Field survey and carbon sequestration estimation.  - The methodology for carbon sequestration was not covered in this section.

189. Figure 2. Carbon sequestration - t ha year or kg per pixel? What does the green strip in Figure 2 represent?

I recommend presenting the developed models in a separate table to enhance the visibility of the equations. Including alphabetical labels (a, b, c, etc.) in the figure does not effectively communicate the needed information within the text. The same applies to figure 8.

Based on the methodology, the field plots were set up between May and August 2018. Figure 2 illustrates carbon sequestration on an annual basis. Further clarification regarding the carbon stock/sequestration in this context is required.

191 I recommend positioning this section as 3.1.

203 Xian?

209. Figure 3. It would be helpful to visualize the distribution of some species from part b) in part a), as they are not currently represented there. For example, Salix or Paulownia.

219 Landsat? In the methodology section GF-2 was mentioned.

221 Figure 4 (5)

236 Figure 5. I recommend removing part a) as part b), which is more informative, duplicates its content. Explain P in the equations.

Including additional statistics (e.g. F-ratio, SE, P value) will be beneficial for understanding the polynomial regression.

269-274 Add (Figure 8).

304, 312 This section would be more appropriately introduced with a new paragraph.

417 Including a Conclusions section will be beneficial for the readers.

 

430 Check the Format of References for MDPI.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors significantly improved their manuscript using the reviewer's suggestions.

Reviewer 4 Report

Comments and Suggestions for Authors

No more questions.

All the best.