Usage PlanetScope Images and LiDAR Point Clouds for Characterizing the Forest Succession Process in Post-Agricultural Areas

Round 1

Reviewer 1 Report

Submitted article falls into the scope of Sustainability journal. The article is focused on the use of  PlanetScope and LiDAR data for forest assessment.

Abstract should contain brief and most important information about the results.

Introduction section is poor. There is a lack of information on the use of remote sensing data in this area of research. Unfortunately, I also did not find the objectives of the study, which should be clearly defined at the end of this section.

I recommend moving the “Study area” chapter under Materials and Methods. Please, check all the abbreviations, if they are explained in the first mention (e.g. ALS).

Are Figure 3 and Figure 1c the same? I don’t understand the Figure 5. Why do you visualize the left and right side of the whole map separately?

In the text, it is necessary to mention first Table 1, then Table 2.

From my point of view, I recommend rewriting the Materials and Methods chapter. It is a little bit confusing and hard to read and understand. All the Figures and Tables should be explained in the text, not just to illustrate some things.

Discussion chapter - discuss your results with the findings of other authors (references), whether your study is consistent with other studies. This form of discussion is another “Introduction”.

Conclusions are very general and should be in line with the aims of the study clearly defined at the end of Introduction section.

The article is written very confusedly and does not provide any significant information about the use of the mentioned data. I recommend the authors to rewrite the article according to the rules of how a scientific article should look. Perhaps I explained well why I recommend rejecting this contribution.

Author Response

Dear Reviewer,

Thank you very much for the review. All comments were appropriate. The Paper has been corrected. Revisions are highlighted using the "Track Changes" function in Microsoft Word.

Detailed Comments You can find in the attachment - PDF file

Author Response File: Author Response.pdf

Reviewer 2 Report

Sustainability - Review of Manuscript

Subject: Manuscript ID:  sustainability-1933509 “Usage PlanetScope Images and LiDAR Point Clouds for Characterizing the Forest Succession Process in Post-agricultural Areas”

 

General comments:

 

The focus of this manuscript is to document the use remote sensing data sources, specifically digital satellite imagery and airborne LiDAR, to quantify the extent of secondary forest succession (natural afforestation) on abandoned farm land. Existing cadastral data do not adequately update changes in forest cover, nor include forest succession that is found on abandon farmland, in their estimates of forest area.

Methods were designed to compare and contrast five estimators of forest area on selected land parcels: (1) cadastral data; (2) image classification of PlanetScope imagery; (3) image classification of Sentinel-2 imagery; (4) analysis of Airborne Laser Scanning (LiDAR) point cloud data; and (5) manual photointerpretation of orthophotomaps. LiDAR data also provides metrics of forest structure. Description of how training and validation data were collected is vague, needs more detailed information. How were point locations selected? Random or systematically? Stratified among LULC classes? How was the number of points within each LULC class determined, both for training and validation data sets.

 

Results demonstrate the potential advantage of using remote sensing data for monitoring changes in forest cover when cadastral data is not updated on regular basis. Main criticism is the somewhat arbitrary conclusion the forest cover estimated from classified PlanetScope imagery were better because estimates were closer to values obtained from LiDAR data. Why were LiDAR results chosen as the reference point?

 

English expressions could be improved throughout document – e.g., use of “ the value of” can be removed.

 

Specific items (see also comments in attached PDF)

 

L69 date(?)

L73 date(?)

L91-92 for clarification, these are independent validation points. How many validation points for each LULC category?

L106 “Airborne”

L108 “ground”

L131-2 awkward sentence, reword

Clarify, in cadastral database, a single parcel can be classified under multiple LULC categories? I am assuming cadastral database in similar to polygon vector layer where one attribute can only have one discreet LULC value, not multiple value

 

L134-6 & Figures 4 & 5 – should be consistent in classification – “Forest” vs “Forest succession”

L159-65 – awkward descriptions comparing estimated area (& % area) of forest land among classification methods. Perhaps select one method as the ‘control’ from which to compare the other methods.

L166-9 – why is having estimate closer to ALS method ‘better’? What makes ALS the more preferred estimate of forest or forest succession?

 

Table 2 – 4-decimal places for user and producer percent accuracy not warranted. One-decimal place will suffice.

 

L174 – “Airborne”

 

Figure 6(a) – Color ramp is very difficult to differentiate different shades of green. Suggest classification color ramp with at most 7 colors. Are forest height estimates strictly for forested areas, including areas of ‘no succession’ shown in Figure 5?

 

Results often refer to ALS, while discussion more often mentions LiDAR. Use consistent acronym throughout manuscript.

 

L192 – “Forest definitions in low are …” I don’t understand this sentence.

L200-1 – reword “an inventory of the land use is done not often” to “an inventory of the land use is not done often”

 

L238 – image classification has errors, it does not provide “exact data” . Re-phrase.

L274 – not really ‘long-term’, but does suggest that forest succession is occurring. To definitively measure forest succession, estimates at two points in time are required. You only have data at one point in time.

 

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you very much for the review. All comments were appropriate. The Paper has been corrected. Revisions are highlighted using the "Track Changes" function in Microsoft Word.

Detailed Comments You can find in the attachment - PDF file

Author Response File: Author Response.pdf

Reviewer 3 Report

This scientific article that we have appraised is a high quality work.

It is well written, clear, precise, relevant in its form and especially in terms of its demonstration. The methodology is clearly presented, the demonstration is of quality and allows a valid answer to the questions asked. The figures are numerous and really support the demonstration.

The bibliographical references are numerous, recent, in short it is a very relevant scientific analysis.

 

This excellent quality research work deserves to be validated as it is.

 

Author Response

Dear Reviewer,

Thank you very much for the review. The Paper has been corrected according to the reviewer’s suggestion and comments. Revisions are highlighted using the "Track Changes" function in Microsoft Word.

Reviewer 4 Report

Dear Author, please find my personal comments and suggestion for your manuscript.

-Title:

Title is appropriate. It covers the research content.

-Abstract

Compliant with journal writing rules. Concise and clearly arranged. Only a few sentences about the method can be given. The achievement of your classification accuracy in the study can be given.

-Keywords:

-Instead of spatial GIS analysis, please prefer GIS analysis or spatial analysis

-Instead of secondary forest succession, please use land management (Because it's highlighted in the title.)

-Introduction

This chapter is pretty short and concise. In this section, readers may want to see information about similar studies done in the past. The popularity of your work can make it easier for you to reach similar researchers. You can include the advantages and disadvantages of similar studies carried out with LiDAR and satellite images. Many citations/literatures used in the Discussion section can be used in the introduction. In this section, you can also state your study purposes as the last paragraph.

-Material ve Method

You can separate the material and method part. Title numbers should be corrected in your work. For example, Study area and Material and method title numbers are the same. Perhaps the Study area should be renumbered under material and method. Please look at Line:47 and 65.

Line 65. The labels (a, b, and c) you use in Figure 2 should be explained in your figure title.

Figures resolution and the order of tables are understandable.

You can give it to the computer/processor features you use in the analysis.

The study area and location are available for foreign readers.

-Results

Line 127 and Line 137 -141.

i.e., “The LULC classes as a result of PlanetScope classification are shown below (Figure 4, 137 [21]). The accuracy assessment parameters for LULC classes are presented in Table 2. The 138 total parameter – Overall Accuracy was in the value of 96.40% and Kappa coefficient as 139 94.52% (for Sentinel-2 image classification the accuracy parameters were on a similar 140 level). The results of PlanetScope classification as the identified forest succession areas are 141 shown in Figure 5 [21].”

This paragraph is your results. However, when I read the paragraph I saw that you are using reference “21”. The results stated in these sentences belong to your classification results. Why did you use citation number 21 here? The sentence is given above. I think you've stated that it's the same as the conclusions of a similar study. However, you can address this in the discussion section.

The classification method success and controls applied are scientifically appropriate.

-Discussion

You have sentences that can be given in the introduction section. You can move some of your sentences to the introduction section.

Wishes,

Author Response

Dear Reviewer,

Thank you very much for the review. All comments were appropriate. The Paper has been corrected. Revisions are highlighted using the "Track Changes" function in Microsoft Word.

Detailed Comments You can find in the attachment - PDF file

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors tried to correct the first version according to reviewer's recommendation. The first part (Abstract, Introduction, aims, Materials and Methods, and also Results) are suffciently written. However, I am still dissatisfied with the discussion and the conclusion. The discussion is written as an Introduction. Discussion means to discuss the results with other authors and desribed how are (or not) in agreement. Conclusion should contain concrete, the most important results. I also recommend checking the references cited in the text. Maybe I explained well, why I recommend publishing it with major revision.

Author Response

Reviewer 1

Dear Reviewer,

Thank you very much for the review. Paper has been corrected. Revisions are highlighted using the "Track Changes" function in Microsoft Word.

Detailed Comments:

The authors tried to correct the first version according to reviewer's recommendation. The first part (Abstract, Introduction, aims, Materials and Methods, and also Results) are suffciently written. However, I am still dissatisfied with the discussion and the conclusion. The discussion is written as an Introduction. Discussion means to discuss the results with other authors and desribed how are (or not) in agreement. Conclusion should contain concrete, the most important results. I also recommend checking the references cited in the text. Maybe I explained well, why I recommend publishing it with major revision.

Discussion and Conclusions have been corrected - Revisions are highlighted in Microsoft Word file

Round 3

Reviewer 1 Report

From my point of view, it could be published in this form.