The Root of Urban Renewal: Linking Miyawaki Afforestation to Soil Recovery

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comments:

Line 36-112:There is an insufficient discussion on the potential limitations or controversies associated with the Miyawaki method of Afforestation. It is recommended to incorporate and reference literature addressing its constraints, such as cost-effectiveness concerns.

Line 114-136：How about control sites and control soil?What is the control soil types ?No any plants in control sites and no change for soil in the past time?Please describe.

Line 219-222: Please add the meanings of alphabetic symbols in formulas.

Line 254: 4.Discussion  The permeability improvement factor, MAR,MBC of the Housing Authority site are extremely high , but no potential abnormal causes (such as soil mixture variations) have been explored. It is suggested to supplement.

Line 285-301:The soil in the microforests, which was replaced with a mixture of peat moss, topsoil, and sand in equal volumes ,is different from the control of undisturbed soil. There should be large gap for soil physical and biological characteristics. Please add the the discussion about it.

Author Response

Line 36-112:There is an insufficient discussion on the potential limitations or controversies associated with the Miyawaki method of Afforestation. It is recommended to incorporate and reference literature addressing its constraints, such as cost-effectiveness concerns.

Response: Thank you. We added a paragraph and provided additional citations for this point.

Line 114-136：How about control sites and control soil?What is the control soil types ?No any plants in control sites and no change for soil in the past time?Please describe.

Response: We added information about the control plots (consisting of grass only) and soil types and added a figure to illustrate the composition (new Figure 3)

Line 219-222: Please add the meanings of alphabetic symbols in formulas. -
Response: We added the meanings for each symbol within the text below the formulas

Line 254: 4.Discussion  The permeability improvement factor, MAR,MBC of the Housing Authority site are extremely high , but no potential abnormal causes (such as soil mixture variations) have been explored. It is suggested to supplement.

Response: We added a grain size distribution chart and some supplemental explanation

Line 285-301:The soil in the microforests, which was replaced with a mixture of peat moss, topsoil, and sand in equal volumes ,is different from the control of undisturbed soil. There should be large gap for soil physical and biological characteristics. Please add the the discussion about it.

Response: Our Figure 3 helps to address how the added soil mixture resulted in different soil physical characteristics. We added an explanation in the Discussion where you suggested. 

 

 

 

Reviewer 2 Report

Comments and Suggestions for Authors

This is an interesting paper but it has some shortcomings.

My main concerns are related to:

• non-random soil sampling prone to strong spatial auto-correlation;
• missing information regarding the species composition of the tree/shrub canopy overlying the imaginary soil sampling pentagon at each site (as illustrated in Fig. 2);
• complete lack of the section dedicated to data analysis methodology;
• reference to mean comparisons after employing the Mann-Whitney test.

I also strongly recommend a different plot layout in Figures 3-5 (see my comments within the manuscript) and reducing the redundant information throughout the sections Introduction, Discussion and Conclusions. Therefore, the main text should be shorten.

In conclusion, the manuscript can and should be improved.

Comments for author File: Comments.pdf

Author Response

Thank you so much for your thoughtful review of our manuscript. We have gone through each change you suggested on the article and made them. We feel that the paper is much stronger now because of your feedback and are grateful for your insight and suggestions.

• non-random soil sampling prone to strong spatial auto-correlation;
  Response: Yes, we added the wording you suggested. Thank you.
• missing information regarding the species composition of the tree/shrub canopy overlying the imaginary soil sampling pentagon at each site (as illustrated in Fig. 2);
  Response: We added the species list that summarizes the plantings for each site (Table 2) and explained that the control plots were just grass.
   
• complete lack of the section dedicated to data analysis methodology;
  Response: Thank you, we added the data analysis section and removed information about data analysis from the other parts of the Methods.
• reference to mean comparisons after employing the Mann-Whitney test.
  Response: Thank you - we made sure to refer to medians instead of means and replaced any use and reference to Kruskall-Wallis to the manually calculated Mann-Whitney exact method.  

Comment: I also strongly recommend a different plot layout in Figures 3-5 (see my comments within the manuscript) and reducing the redundant information throughout the sections Introduction, Discussion and Conclusions. Therefore, the main text should be shorten.

Response: Yes, we changed the format of the plots from bar graphs to box plots as you suggested and reduced the redundant information. Thank you for pointing that out.

In conclusion, the manuscript can and should be improved.

Here are each of the comments made on the manuscript and how we addressed them:

A1 - Wording was changed as you suggested
A2 - Yes, wording was changed as you suggested
A3 - This point was clarified as you suggested
A4 - A table of the species composition of the tree/shrub canopy was created and inserted. We created the table for all species planted in the microforest instead of just what was overlying the soil sampling pentagon to give a clearer description of the microforests that can be used for people who have interest in furture research and practice.
A5 - A section called Data Analysis was created and this highlighted section was moved there. That said, we re-analyzed with Mann-Whitney instead of Kruska-Wallis as you appropriately suggested.
A6 - Same as above
A7 - We created the Data Analysis section and reanalyzed the data using Mann-Whitney U exact tests, as you suggested.
 -  Please note, by reanalyzing using Mann-Whitney tests, some of the p-values changed (particularly those for porosity, density and void ratio). Updated p-values were provided.

A8 - Thank you - We reworded to focus on medians instead of means.
A9 - The data in Table 3 are based on a pooled sample of data from each site so are not means or medians. We clarified this in the text.
A10 - Abbreviations were written out
A11- Abbreviations were written out
A12 - Bar plots were all replaced with box plots indicating medians. 
A13 - The seciton was moved to start of Conclusion
A14 - Statement was deleted due to redundancy
A15 - Deleted due to redundancy
A16- Deleted due to redundancy
A17- All mentions of means were changed to medians based on Mann-Whitney tests

All in-text edits were accepted.

Response: We believe that the manuscript is much stronger because of your thoughtful comments and suggestions. Thank you!

Reviewer 3 Report

Comments and Suggestions for Authors

GENERAL COMMENTS

Miyawaki-style microforests involve intensive soil preparation and planting a high density of native tree and shrub species to mimic a natural climax forest. This manuscript analyses the improvement of selected soil physical and biological properties in highly degraded urban environment after planting this type of microforest. Results showed that microforest establishment ameliorate carbon sequestration, microbial activity and permeability within one to three years since plantation.

This study is novel and it provides relevant information that may be useful to manage rapid restoration of ecological function in urban environments. The novel data set obtained is very valuable and provides new insight to evaluate soil properties changes during restoration progress. The references are also up-to-date. In opinion this manuscript can be accepted for publication after small adjustments.

The physical, chemical and biological properties studied are very relevant. However, I’m wondering if other basic soil properties, for example pH, electrical conductivity, nitrogen, phosphorus, micronutrients, etc., have been also analyzed. Including more data allows for a more complete picture of how afforestation affects soil crucial properties or processes, leading to a stronger and more comprehensive scientific argument. For example, adding more soil pH results to a manuscript is beneficial because soil pH is a "master variable" that profoundly impacts plant nutrient availability, microbial activity, and overall soil health.

 

SPECIFIC COMMENTS

Title

The title is relevant and well stated

Abstract

The abstract provides a comprehensive background information. The specific objectives have been added. Results and conclusions are adequately summarized.

Introduction

The introduction highlights the development and use of the Miyawaki method. The advantages of this method for restoration of degraded urban surface are emphasized.

Also, the importance of enhancing the upper soil layers with organic amendments is addressed. It is also shown that there is a gap in the knowledge related to this issue. On this basis the authors proposed and innovative work.

The introduction is well written and referenced and and culiminates into well stated and achievable study objectives.

Material and methods

The material and methods section successively addresses “site selection and preparation”, “soil sampling”, “soil physical and chemical analysis”, “hydraulic permeability and conductivity”, “total carbon analysis”, “soil microbial activity: respiration and biomass”, and “microbial biomass carbon”.

Site selection and preparation are well described. Soil sample procedures are clearly stated. Also analytical procedures are clear.

However, it is recommended that authors provide several adjustments:

• Subsection 2.1. “Site Selection and Preparation”
• Line 158. The title of subsection 2.3, namely “soil physical and chemical analysis” is too general in this context. Pleas, consider to ther options as, for example, “soil porosity”.
• Line 168. The equation for porosity has been written in bold. Please use a similar format in all the equations along the text.
• Lines 168, 169, 170 and 179, etc., etc. Please, number the successive equations.

Moreover, for site preparation a mixture of peat, soil and sand was used. Finally, are there analysis on the composition of this mixture?.

Results

The results of the physical, chemical and biological properties studied are described in detail.

Figures and Tables are well presented and captioned.

Discussion

This section is well written and referenced. The following topics have been discussed:

• - Rapid improvement of soil structure.
• - Organic carbon accumulation and soil respiration.
• - Early signs of ecological self-organization.

The discussion is well organized. Comparisons with other studies have been made when possible (in the context of soil texture improvements).

It is recommended that authors should provide a statement about implications and future prospects of their study.

Conclusions

The conclusions are supported by the data

Author Response

Thank you for taking the time to review our manuscript. We have made the edits that you suggested:

Subsection 2.1. “Site Selection and Preparation”

• Line 158. The title of subsection 2.3, namely “soil physical and chemical analysis” is too general in this context. Pleas, consider to ther options as, for example, “soil porosity”.
  Response: This has been changed.
• Line 168. The equation for porosity has been written in bold. Please use a similar format in all the equations along the text.
  Response: We took away the bold font for all equations.
  
  
• Lines 168, 169, 170 and 179, etc., etc. Please, number the successive equations.
  Response: We numbered the equations by putting "Equation #" before the equation. We hope this was what you wanted.

Moreover, for site preparation a mixture of peat, soil and sand was used. Finally, are there analysis on the composition of this mixture?.
Response: Yes. Thank you for pointing out the need for more soil composition being presented. We added this information as Figure 2. 

It is recommended that authors should provide a statement about implications and future prospects of their study
Response: Thank you - we added a statement about implications and future prospects to the Conclusion.

Comment: "The physical, chemical and biological properties studied are very relevant. However, I’m wondering if other basic soil properties, for example pH, electrical conductivity, nitrogen, phosphorus, micronutrients, etc., have been also analyzed. Including more data allows for a more complete picture of how afforestation affects soil crucial properties or processes, leading to a stronger and more comprehensive scientific argument. For example, adding more soil pH results to a manuscript is beneficial because soil pH is a "master variable" that profoundly impacts plant nutrient availability, microbial activity, and overall soil health."

Response: We added information about the soil pH testing and results. These results were not significantly different so we didn't add it to the draft manuscript but happy to incorporate them into the revisions. We did not conduct further soil chemical analysis for this paper since the focus was on permeability and microbial development but will be conducting further soil analysis in future studies, and now indicated as such in the Conclusion when we discuss future studies.

Thank you for your thoughtful review. 

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

The second version of the manuscript has been improved significantly. Nevertheless, I have found (very likely) some mistakes in the Results section (see the annotated PDF). I have also included in the uploaded PDF some recommendations that you should consider for complying with the scientific standards.

Comments for author File: Comments.pdf

Author Response

We thank you again for your effort in reviewing our paper. We have made changes based on your suggestions (see attached).

Change 1 - We added * for the species whose canopies were over the soil sampling locations based on the pentagon for each site to Table 2.

Change 2- For the soil porosity, void ratio and density, we ran into issues with the significance levels (p=0.1) because the n=3 and there was only one data point for each microforest. With no replicates and n=3, the Mann-Whitney test has very low power, and p=0.10 is the mathematical floor (Rosner and Grove 1999). This was not an issue for the other tests since we had more replicates at each microforest, as described in the methods (such as 4 replicates for Total Carbon, 6 replicates for the microbial analysis). By virtue of this point, we decided to remove mention of p-values and instead note the percentage of change (lines 262-269). 

Rosner, B. and D. Grove. 1999. Use of the Mann Whitney Test for Clustered Data. Harvard Medical School, 181 Longwood Ave, Boston, MA 02115, U.S.A

Change 3 - Figure numbers were removed from the Discussion. 

Author Response File: Author Response.pdf