Evaluation of the 20-Year Restoration Process in an Air-Pollution-Damaged Forest near the Ulsan Industrial Complex, Korea

Round 1

Reviewer 1 Report

This paper presents the results of a 20-year restoration process in an air pollution-damaged forest. There are various comments and suggestions that need to be addressed and clarified.

 

It is stated that the restoration of the forest, which was harmed by air pollution, was evaluated. However, it is unclear what type of forest it was. Species composition? What were the main key characteristics of this forest (approximate age, it was a closed forest or not, average height and diameter, etc.)?

 

The reference site is not described in any detail. What types of forests are there? The dominant species in this forest? What are the key characteristics of the forest?

 

There are existing tree plantations in the research region (Pinus thunbergii, Populus tomentiglandulosa), according to the data shown in Figure 1. Why did the authors not research restoration based on these plantations and create new ones?

Please clarify the scheme of restoration (Lines 139-141). “… by planting three-year-old seedlings (nine each for Quercus serrata, Alnus firma, and Ligustrum japonicum…”. According to this statement, only nine seedlings of each species were planted? You must detail the size of the restoration site where the seedlings were planted. And why did you not indicate in Figure 1 the borders of the restoration site?

 

Subsec 3.5. Exotic species. What do you mean by exotic species? The list of plant species that will be exotic is significant and will vary widely based on the locale for each geographical area. Why did you not provide a list of plant species that you deem exotic? Most critically, though, what criteria did you use to distinguish between the exotic and non-exotic plant species?

Author Response

Dear Reviewer,

Thank you for your valuable comments.

We responded sincerely to the reviewer’s comments as the attached document.

Sincerely yours.

C.S. Lee

Response to Reviewer 1

 

Comments and Suggestions for Authors

This paper presents the results of a 20-year restoration process in an air pollution-damaged forest. There are various comments and suggestions that need to be addressed and clarified.

 

It is stated that the restoration of the forest, which was harmed by air pollution, was evaluated. However, it is unclear what type of forest it was. Species composition? What were the main key characteristics of this forest (approximate age, it was a closed forest or not, average height and diameter, etc.)?

 Since our study began after vegetation was damaged, there is no information on previous vegetation conditions. However, looking at vegetation of the area far from the industrial complex, such as our reference site, it is believed that natural vegetation was dominated by mixed forests centered on Quercus serrata and Pinus thunbergii. In addition, artificial afforestation was made through human interference other than industrial activities, and the species introduced for afforestation, mainly Robinia pseudoacacia and Alnus firma invaded there. Those forests remain mature with a height of about 15 m and a diameter of more than 20 cm. On the other hand, afforestation is carried out in the form of afforestation to protect landslides rather than for the purpose of economic forests, and the native plants usually established under afforested trees, and except for the artificially introduced afforestation species, the species composition is very similar to natural forests.

The reference site is not described in any detail. What types of forests are there? The dominant species in this forest? What are the key characteristics of the forest?

The following contents were added by reflecting the reviewer's comments:

The vegetation of the reference site is dominated by oaks including Quercus serrata but a number of Pinus thunbergii have also established because it is located on the coastal area. The trees that dominate the forest are about 15 m high and more than 20 cm in diameter and thus, form a mature forest. In addition, afforestation species such as Alnus firma, Robinia pseudoacia, and Pinus rigida have also invaded under the influence of afforestation created around them.

There are existing tree plantations in the research region (Pinus thunbergii, Populus tomentiglandulosa), according to the data shown in Figure 1. Why did the authors not research restoration based on these plantations and create new ones?

The background of the restoration practiced by selecting other plants instead of selecting the existing afforestation tree species is as follows:

Pinus thunbergii is an early successional species in the region and is vulnerable to air pollution. Populus tomentiglandulosa is a hybrid species that has ecological problems, and this species is also vulnerable to air pollution. Therefore, Quercus serrata, which forms potential natural vegetation in this area and is tolerant to air pollution, was selected as a plant for restoration. Ligustrum japonicum is considered a native plant in the region and is tolerant to air pollution. Alnus firma was selected as a nurse plant as a nitrogen-fixing plant. Lines 124 – 129.

Please clarify the scheme of restoration (Lines 139-141). “… by planting three-year-old seedlings (nine each for Quercus serrata, Alnus firma, and Ligustrum japonicum…”. According to this statement, only nine seedlings of each species were planted? You must detail the size of the restoration site where the seedlings were planted. And why did you not indicate in Figure 1 the borders of the restoration site?

We revised these parts by adding the scheme of restoration and by expressing the borders of the restoration site. Lines 145 – 148 and Figure 1.

Subsec 3.5. Exotic species. What do you mean by exotic species? The list of plant species that will be exotic is significant and will vary widely based on the locale for each geographical area. Why did you not provide a list of plant species that you deem exotic? Most critically, though, what criteria did you use to distinguish between the exotic and non-exotic plant species?

We have defined exotic species as species that occur outside the natural geographic range. Exotic species were analyzed by restricting them to species designated by the Ministry of Environment of the Republic of Korea.

Author Response File: Author Response.docx

Reviewer 2 Report

Reviewer: Comment to Manuscript ID: forests-2460397

Specific comments and questions: 

1- The introduction section has to be rewritten! To include the following contents (1) The background of the proposed topic. (2) Previous research experience, results, reality and problems and evaluation. (3) Explain your reasons for doing this research. Introduce the nature and scope of the topic and its importance, highlighting the purpose of the study or the problems to be solved. (4) Methodology used in the research process, new findings and significance of the research work. 

2- Is the reference [25] in the study area profile not in English? Please revise the format!

3- What does line 117 GG refer to? In the main text, it only says the abbreviation GG.

4- In Figure 2 , Figure 4 and Figure 6, what do a,b, c, d, e, bc and cd refer to? Please make a note!

5- In lines 115-119, the author describes several abbreviations which do not correspond to the several abbreviations illustrated in Figure 3! Please check and add the relevant abbreviations!

6- The authors of the discussion section cite a lot of literature. Can you make a table to organize the results of previous research compared to current research?

7- The conclusion is written macroscopically; The conclusion of the dissertation is the final, overarching conclusion, not a short-answer repetition of the chapters' summaries in the body of the text. The decision should be clear, rigorous, complete, accurate, and concise.

 

Author Response

Dear Reviewer,

 

Thank you for your valuable comments.

We responded sincerely to the reviewer’s comments as the attached document.

Sincerely yours.

C.S. Lee

Response to Reviewer 2

 

Comments and Suggestions for Authors

 

Reviewer: Comment to Manuscript ID: forests-2460397

Specific comments and questions: 

1- The introduction section has to be rewritten! To include the following contents (1) The background of the proposed topic. (2) Previous research experience, results, reality and problems and evaluation. (3) Explain your reasons for doing this research. Introduce the nature and scope of the topic and its importance, highlighting the purpose of the study or the problems to be solved. (4) Methodology used in the research process, new findings and significance of the research work. 

We revised the Introduction part by accepting reviewer’s comment. Lines 87 – 91.

2- Is the reference [25] in the study area profile not in English? Please revise the format!

We added a reference written in English. Reference No. 28.

3- What does line 117 GG refer to? In the main text, it only says the abbreviation GG.

It means grassland dominated by grass. We revised this part to reduce misunderstanding of the readers. Lines 131 – 132.

4- In Figure 2 , Figure 4 and Figure 6, what do a,b, c, d, e, bc and cd refer to? Please make a note!

We added explanations for them.

5- In lines 115-119, the author describes several abbreviations which do not correspond to the several abbreviations illustrated in Figure 3! Please check and add the relevant abbreviations!

Thank you. We revised them.

6- The authors of the discussion section cite a lot of literature. Can you make a table to organize the results of previous research compared to current research?

Although lime was widely used to improve acidified soil, literature that verified the effect of dolomite that can supplement both calcium and magnesium lost due to acidification as well as improvement of acidification was cited. On the other hand, when the soil becomes more acidic, aluminum toxicity appears, and the role of organic matter is important as a factor that inactivates toxic aluminum ions in addition to improving acidification measures to reduce the damage. The literature dealing with these issues was cited.

On the other hand, in contaminated areas such as industrial complexes, vegetation damage was diverse. Weak damage is limited to visible damage. However, in severe cases, as tall trees are affected first and the damage continues, the entire layer of vegetation is affected step by step. Consequently, complex and diverse forests is reduced to simple grassland or bare land.

In order to restore such vegetation, it is necessary to restore it through the selection and introduction of plants resistant to the contaminated environment. And it is very important to evaluate its effectiveness after restoration. Since the goal of restoration is to restore its former appearance, that is, its full nature, the restored vegetation should be similar to that of intact nature, has high diversity, and has no unsuitable factors such as exotic species, and must be sustainable. Documents that comprehensively deal with these problems were cited.

7- The conclusion is written macroscopically; The conclusion of the dissertation is the final, overarching conclusion, not a short-answer repetition of the chapters' summaries in the body of the text. The decision should be clear, rigorous, complete, accurate, and concise.

    To help readers understand the derived conclusions, the background of the study and the results obtained through the study were summarized. By synthesizing these data, it was concluded that soil improvement and restoration through the selection and introduction of tolerant species are essential to achieve successful restoration in areas such as industrial complexes where pollutant emissions occur.

Author Response File: Author Response.docx

Reviewer 3 Report

Evaluation of the 20-year restoration process in an air pollution-damaged forest near the Ulsan Industrial Complex, Korea

Dong Uk Kim, Bong Soon Lim, Ji Eun Seok, Gyung Soon Kim, Jeong Sook Moon, Chi Hong Lim and Chang Seok Lee

 

- No climatic characteristics of the study area.

- A complete description of the soils is not presented. No soil name and description. What is the thickness of the top soil organic horizon? What is the granulometric composition? No data on the content of organic carbon and nutrients (nitrogen, phosphorus, and potassium). What happened to the soil during the 20-year experiment? How was the forest litter formed? Could the forest litter have influenced changes in pH, Ca²⁺, Mg²⁺ and Al³⁺ contents? Or maybe water erosion had an impact?

- Usually, when studying the change of Al³⁺ content in the soil, one also studies the change of H⁺. Why are no data on H⁺ given?

- How was dolomite applied to the soil?

- Line 277-301. An example of the use of sludge in conjunction with dolomite is given. In the experiment only dolomite was used. How correct is this discussion in this case?

Author Response

Dear Reviewer,

 

Thank you for your valuable comments.

We responded sincerely to the reviewer’s comments as the attached document.

Sincerely yours.

C.S. Lee

Response to reviewer’s comments (Reviewer 3)

 

Comments and Suggestions for Authors

Evaluation of the 20-year restoration process in an air pollution-damaged forest near the Ulsan Industrial Complex, Korea

Dong Uk Kim, Bong Soon Lim, Ji Eun Seok, Gyung Soon Kim, Jeong Sook Moon, Chi Hong Lim and Chang Seok Lee

 

- No climatic characteristics of the study area.

We revised this part by adding as the follows:

Ulsan is located in southeastern coast of the Korean Peninsula and faced on the East sea (126°46′15″ to 127°11′15″ E longitude, 37°25′50″ to 37°41′45″ N latitude; Figure 1). Topography of Ulsan is a concave plain surrounded by high mountains in the west and east. The elevation of the study area, Mt Dotjil ranges from 20 to 89 m above sea level. The parent rock of Ulsan is usually composed of sedimentary rock, and the flat land beside rivers and streams is consisted of alluvium. Soil in these areas was classified into the Eutrudepts greatgroup of Udepts suborder in Inceptisols order, which developed on sedimentary bedrock. Soil based on soil texture was silty loam. Due to the poor development of vegetation, the thickness of the litter layer was thin within 1 cm.

The climate of Ulsan is continental, with warm and moist summers and cold and dry winters. From 1991 to 2020, the mean annual temperature was 13.95°C and the mean annual precipitation was 127.0 cm (Meteorological Administration 2021). Lines 93 – 104.

 

- A complete description of the soils is not presented. No soil name and description.

We added the information by accepting reviewer’s comments. Lines 96 – 101.

- What is the thickness of the top soil organic horizon? What is the granulometric composition?

We added the information by accepting reviewer’s comments. Lines 96 – 101.

 

- No data on the content of organic carbon and nutrients (nitrogen, phosphorus, and potassium).

Our research has focused on improving soil acidified by air pollution. Therefore, it was investigated focusing on changes in Ca, Mg, Al, and pH with big changes in acidified soil.

What happened to the soil during the 20-year experiment?

We mentioned that in Lines 211 – 214 as the follows: After treatment with the soil ameliorator, the soil pH, Ca²⁺, and Mg²⁺ contents increased, but then decreased 20 years after the treatment. The Al³⁺ content showed the opposite trend: decreasing after treatment, but increasing again 20 years after the treatment (Figure 2).

How was the forest litter formed? Could the forest litter have influenced changes in pH, Ca²⁺, Mg²⁺ and Al³⁺ contents? Or maybe water erosion had an impact?

The litter layer was formed, but as mentioned earlier, the thickness was not thick due to poor vegetation development. Therefore, it is judged that the effect on the physicochemical properties of the soil is not significant.

- Usually, when studying the change of Al³⁺ content in the soil, one also studies the change of H⁺. Why are no data on H⁺ given?

We measured the pH that could explain the H⁺ ion concentration.

- How was dolomite applied to the soil?

We mixed commercial dolomite with sludge and sprayed it on the soil surface and mixed it with topsoil to increase its effectiveness.

- Line 277-301. An example of the use of sludge in conjunction with dolomite is given. In the experiment only dolomite was used. How correct is this discussion in this case?

We mentioned that we used mixture of dolomite and sludge as a soil ameliorator in Lines 138 -139.

 

Author Response File: Author Response.docx

Reviewer 4 Report

Dear Authors,

I have reviewed the paper "Evaluation on the restoration process progressed for 20 years in an air-pollution damaged forest around the Ulsan Industrial Complex, Korea  ". In my opinion the aims are interesting, but there are some important flaws that I think I well explained in the attached file

 

 

Comments for author File: Comments.pdf

I suggest a  Moderate editing of English language 

Author Response

Dear Reviewer,

 

Thank you for your valuable comments.

We responded sincerely to the reviewer’s comments as the attached document.

Sincerely yours.

C.S. Lee

Response to Reviewer 4

 

The phrase is confusing. Please rewrite.

We revised this part to make it easier for the reader to understand. Lines 40 – 44.

 

Not ebook ??

Yes, we added the reference.

 

In my opinion, the main aim of this paper is missed, in the present form it is difficult to consider this paper a research paper.

We revised this part greatly by accepting the reviewer’s comment. Lines 87 – 91.

 

Not ebook. Please, put citations.

We cited a reference related to this part.

 

Not ebook. Phyco-chemical properties

We revised this part. Lines 117, 322, 493, 496.

 

Not ebook. Please, put Latin names

We revised this part exchanging it for a Latin name. Line 132.

 

Not ebook. Please, specify the extension of the study area.

We this pare revised adding the extension of the study area. Lins 164 – 167.

 

This is an aim but not reported in introduction and in my opinion not linked with this work.

We revised the Introduction part and included this in the research purpose. Lines 87 – 91.

 

Again confusion, it is necessary to have clear aims and then present linked conclusion. In the present form this is a very important lack.

We revised the Introduction part and included this in the research purpose. Lines 87 – 91.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have revised the manuscript in response to all comments and suggestions. The manuscript is now ready for publication.

Reviewer 2 Report

The article was edited quite well and agreed to be published!

The article was edited quite well and agreed to be published!

Reviewer 3 Report

All of my comments have been corrected. I have no comments.

Reviewer 4 Report

With the change made the paper was improved. 

It seems necessary to format the references according to the guidelines of the paper

moderate english review