The Ecological Potential of Poplars (Populus L.) for City Tree Planting and Management: A Preliminary Study of Central Poland (Warsaw) and Silesia (Chorzów)
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors,
I have reviewed your manuscript “The potential of poplars (Populus L.) for the sustainable environment of cities” for possible publication in Land.
The baseline idea of your study is relevant, giving an ecological perspective on urban tree planting and management. I enjoyed reading about the history of poplars and the examples you provided. However, I felt that the methodological approach employed to support your ideas could benefit from significant improvement. Some mixed use of concepts and inconsistency in terms are obscuring your arguments.
The manuscript does not flow well, there are mixed topics in paragraphs and then the same topic is discussed or presented in several paragraphs that do not follow each other, as such, the reading does not flow well and there are many sections that read repetitive. This is particularly noticeable in the discussion, which reads as a repetition of the results. Many paragraphs repeat the same ideas multiple times. The conclusion also reads as a shopping list of things that have been established. I believe the Discussion can be significantly shortened or alternatively, combine Results and Discussion in the same section. Many details are missing in the Methods.
Also, you need to discuss the limitations of your study, and not only the methodological limitations (e.g., limited number of studies, language used to find studies). The topic itself of the manuscript can be controversial. First, it seems you are advocating for the use of poplars in urban settings without even considering other species. You briefly mention this in L688-689 (Of course, there is no need to use poplars in each area in cities), but this should be discussed in more detail or at least add some clarifications. The approach of using single species (or groups) is not recommended in cities as we cannot rely on a few species; we need to increase biodiversity in urban forests to increase resilience, especially to climate change.
On this topic, the manuscript overlooks the risk of climate change on poplars and suggests using them in cities without considering this risk. In a very recent study, Wang et al. (2024, Global Ecology and Conservation) assessed the impact of climate change on three poplar species, Populus tomentosa, Populus cathayana, and Populus lasiocarpa in China, and they suggest using a site-specific, categorical planting approach to guide effective forest management practices. In the context of urban environments, it is important to mention that cities can expand the species realised climatic niches, which was shown for five poplar species in cities worldwide: Populus balsamifera, Populus deltoides, Populus nigra, Populus tremula, and Populus tremuloides (See Kednal et al. 2018, Global Ecology and Biogeography). Finally, a global risk assessment of >3000 tree species, included 19 poplar species planted in 119 global cities, and the authors found that 15 species are potentially at risk of increases in temperature in 100 cities (see Esperon-Rodriguez et al. 2022, Nature Climate Change). This caveat should be discussed if you are suggesting the use of poplars in cities. Finally, the manuscript seems to advocate trees as the most effective solution for environmental challenges facing cities, but I disagree with this. I love trees, and they provide many benefits, but they are not always the right answer. There are multiple examples in cities around the world cutting down invasive trees due to their water consumption and restoring with native shrub species. For arid and semi-arid cities facing water scarcity, other vegetation options can be more appropriate than trees. I think this point should also be mentioned even if it is just as a caveat.
The use of references is not well-balanced. For example, in the introduction, you used 13 and then 31 references for single statements. This seems excessive for an introduction. Use key references only. Also, be careful with excessive self-citations, this may not seem an issue because there are too many references in this manuscript, but I found concerning the number of self-citations.
Please, verify that all figures are cited in the text. This lack of care does not reflect well on you. A suggestion on figures, consider merging figures 1-5 can in one single figure.
More detailed comments are listed below.
L15. Why “would have”? I assumed this has already happened, change to “have”?
L28. Some of these keywords are already in the title. Consider replacing them.
L32-35. One sentence paragraph. Merge with the next paragraph.
L39. References?
L35. Provide just key references here. No need to cite 13 studies here.
L45. Provide just key references here. Do you really need 31 references for these statements?
L46-54. This paragraph needs references.
L53. Anthropogenic refers to their origin, not necessarily to their durability and regulation capacity, where did you get this definition from? Reference?
L55. Delete “especially”.
L60. I would say “reduce” and not “limit”.
L65. This information in parentheses doesn’t read well here.
L66. Something reads oddly here “new-planted trees which are failing to establish is significant”.
L67. What do you mean by “planting mature trees”?
L79-88. References needed.
L118. What languages were used to search articles and other publications? How many articles were retrieved and reviewed? How many articles were used on this study? Did you have any criteria for the inclusion of articles in this study?
L139-147.More details are needed here. How many field observations? From which regions and when were these conducted? How many poplar taxa were located in urban areas and in how many locations? Provide a table showing how many studies used these different techniques. What type of analyses were used to identify this one representative cultivar?
L140. Taxa is the plural of taxon, no “taxons”.
L182. Correct to “limited research”.
L183. Delete “urban green spaces”.
L185. How many studies were included here?
L190-194. But many other species can provide these benefits, this is not exclusive to poplars. I think you need to focus here on what is special or unique about poplars. That seems more relevant.
L199. References?
L202-212. This is repetitive. Some of this information has already been mentioned.
L214. Figure 1 is not cited in the text.
L225. Figure 2 is not cited in the text.
L 233-235. It is not clear the relationship between fast growth and reduction of the urban heat island effect. Is it because cities can get more canopy cover faster? Clarify.
L236. What about shade?
L239. Figure 3 is not cited in the text.
L251. Figure 4 is not cited in the text.
L256. Figure 5 is not cited in the text.
L269. Why is this in bold? If it is a quote, you need to add the citation.
L271-275. The fast growth topic has already been mentioned earlier. Group the same topics together so it doesn’t read repetitively and the reading flows better.
L280. What do you mean by “ecological adaptability”? Define for your readers.
L302. Provide scientific name.
L305. What are these “many interesting characteristics”?
L308-324. References needed.
L318. Recommended by who?
L325-336. Is all this based on field observations? If yes, clarify, if no, add references.
L337-341. This fits better in Methods.
L376. You cited first Figure 7 in the text. You need to update figures’ order or cited Figure 6 before.
L377-393. This reads very repetitive. You can summarize this and present these results in a table to improve the flow of the reading.
L394. Who conducted these measurements?
L398. Was this correlation significant? Details are needed in the text.
L414-415. This is not mentioned in the Methods.
L422. Define SGGW in the legend.
L425-426. Missing in Methods.
L425. Why was this tested? What are your working hypotheses?
L443. Figure 10 is not cited in the text.
L461. Correct references’ format.
L462. When did you collect these field measurements? Missing in methods.
L483. What are these “favorable conditions”? Describe for your readers.
L501. Figure 13 is not cited in the text.
L505. What tests were used? Where is the evidence of this paragraph?
L508. Do you mean “SIGNIFICANT increase”? Also, you need to cite a table with those results here.
L516. Missing in Methods.
L516. Delete “the strength of”.
L527. Why forgotten? It seems like they are being used.
L540. What do you mean by “Adaptive re-planting strategies”? Explain for your readers.
L541. A mix of different poplar species or general mix of all types of urban tree species? Because we should advocate for the latter in urban settings to increase biodiversity and resilience.
L546-568. Reads repetitive; all this has been already mentioned. Delete?
L558. Reference?
L569-579. In this section, you repeat three times “sustainable urban development”. Make sure that you don’t repeat the same ideas and topics in different paragraphs.
L580. This has already been mentioned above. Present the same topics together in one paragraph to avoid repetition and improve the flow of the reading.
L587. Why “in conclusion”? This is not the end of the manuscript.
L587-591. Again, this has already been established and mentioned multiple times.
L595. If this is a myth and misunderstanding, then what is the point of discussing the shorten trees' lifespan in L528-583. With this statement, it seems irrelevant (or even false) everything was mentioned above.
L596-599. Delete. It has been mentioned many times.
L600. But in L595 you say this is a myth and misunderstanding.
L604. This does not read as scientific language “Trees in cities live shorter and shorter”. Also, it needs a reference.
L606. What are these species?
L606-607. But this is not a short-lived tree considering that street trees have an average lifespan of 13-20 years. See Smith et al. 2019, Plos One.
L613. But you haven’t defined these favorable conditions.
L624-644. This is a repetition of the results.
L633. Very high compared to what? What is the baseline of comparison here?
L645. Delete “In conclusion”.
L655. What would take 24 years?
L657. What do you mean by “tree activity”? This is the first (and only) time you mention this term.
L658. Reference for maintenance costs?
L661. Define poor conditions.
L677. This is the only time you refer to these as “Berlin variety”. Use the same terminology to avoid confusion.
L681. Provide examples of these mistakes for your readers.
L703. It is possible, so I’d rephrase this and replace the word “impossible”.
L705. Missing bracket.
L714. There is no mention anywhere in the manuscript how many species are or at least how many species were included in this study.
Comments on the Quality of English LanguageRevisions are needed. Some sections are difficult to understand.
Author Response
We would like to thank a lot the reviewer for the fundamental and very useful comments.
Dear authors,
I have reviewed your manuscript “The potential of poplars (Populus L.) for the sustainable environment of cities” for possible publication in Land.
The baseline idea of your study is relevant, giving an ecological perspective on urban tree planting and management. I enjoyed reading about the history of poplars and the examples you provided. However, I felt that the methodological approach employed to support your ideas could benefit from significant improvement. Some mixed use of concepts and inconsistency in terms are obscuring your arguments.
The manuscript does not flow well, there are mixed topics in paragraphs and then the same topic is discussed or presented in several paragraphs that do not follow each other, as such, the reading does not flow well and there are many sections that read repetitive. This is particularly noticeable in the discussion, which reads as a repetition of the results. Many paragraphs repeat the same ideas multiple times. The conclusion also reads as a shopping list of things that have been established. I believe the Discussion can be significantly shortened or alternatively, combine Results and Discussion in the same section. Many details are missing in the Methods.
Comment: We combined Results and Discussion in the same section to avoid repetition and made reading flow better.
Also, you need to discuss the limitations of your study, and not only the methodological limitations (e.g., limited number of studies, language used to find studies). The topic itself of the manuscript can be controversial. First, it seems you are advocating for the use of poplars in urban settings without even considering other species. You briefly mention this in L688-689 (Of course, there is no need to use poplars in each area in cities), but this should be discussed in more detail or at least add some clarifications. The approach of using single species (or groups) is not recommended in cities as we cannot rely on a few species; we need to increase biodiversity in urban forests to increase resilience, especially to climate change.
Comment: We discussed the limitations deaper in the study. We agree that we should increase species in urban forests. However, in the study we concentrate on street wooded areas or trees alleys which are important due to historical approach in urban parks or streets (not in forests which might be nice scope of different study that we consider in the future). Polish cities are full of biodiversity what is not visible eg in West of Europe. We can observe the biodiversity of Warsaw eg. In city crown map (see website: https://mapa.um.warszawa.pl/mapaApp1/mapa?service=zielen&L=en&X=0&Y=0&S=9&O=0&T=3c1f78fe004ffffffffffffffff800003060c00003bbbbbf000018000000x4F&komunikat=off ). So we decided to choose one species which is not described and used for planting since 20C. We found that some species like poplars are not recommended to narrow streets or dense cities esp. in 21C but in some cases like in Chorzów or Warsaw (not so dense cities as Łódź or Kraków due to new period of urbanization after 2nd World War) seems to be forgotten or not considered in spatial planning because of rapid growth or weak wood and damages problems of (P.italica) cars or buildings from previous period (20C) as we want to mention more clear in corrected version of the paper.
On this topic, the manuscript overlooks the risk of climate change on poplars and suggests using them in cities without considering this risk. In a very recent study, Wang et al. (2024, Global Ecology and Conservation) assessed the impact of climate change on three poplar species, Populus tomentosa, Populus cathayana, and Populus lasiocarpa in China, and they suggest using a site-specific, categorical planting approach to guide effective forest management practices. In the context of urban environments, it is important to mention that cities can expand the species realised climatic niches, which was shown for five poplar species in cities worldwide: Populus balsamifera, Populus deltoides, Populus nigra, Populus tremula, and Populus tremuloides (See Kednal et al. 2018, Global Ecology and Biogeography). Finally, a global risk assessment of >3000 tree species, included 19 poplar species planted in 119 global cities, and the authors found that 15 species are potentially at risk of increases in temperature in 100 cities (see Esperon-Rodriguez et al. 2022, Nature Climate Change). This caveat should be discussed if you are suggesting the use of poplars in cities. Finally, the manuscript seems to advocate trees as the most effective solution for environmental challenges facing cities, but I disagree with this. I love trees, and they provide many benefits, but they are not always the right answer. There are multiple examples in cities around the world cutting down invasive trees due to their water consumption and restoring with native shrub species. For arid and semi-arid cities facing water scarcity, other vegetation options can be more appropriate than trees. I think this point should also be mentioned even if it is just as a caveat.
Comment: We added the issue of Climate change and the temperature aspects and important literature on it in revised paper as well as:
- Wang et al. (2024, Global Ecology and Conservation) assessed the impact of climate change on three poplar species ;
- Kednal et al. (2018, Global Ecology and Biogeography) describing issue of cities that can expand the species realised climatic niches, shown for five poplar species in cities worldwide: (Populus balsamifera, Populus deltoides, Populus nigra, Populus tremula, and Populus tremuloides)
- Esperon-Rodriguez et al. (2022, Nature Climate Change),
sugested by the reviewer to point the examples of poplars benefits deaper in revised paper.
In our paper we focused on selected taxa of poplars as trees important due to their growth and alleys properties. We agree that issue of:
- planting of other vegetation (like cover shrubs or creepers) in cities ;
- invasive plants (like Acer negundo, Solidago hybrida or Fallopia ×bohemica) which displace other species as poplars, are also very important to mention due to their expansion and climate change approach.
However those aspects might be the scope in further research.
The use of references is not well-balanced. For example, in the introduction, you used 13 and then 31 references for single statements. This seems excessive for an introduction. Use key references only. Also, be careful with excessive self-citations, this may not seem an issue because there are too many references in this manuscript, but I found concerning the number of self-citations.
Comment: We agree. We used key references only in the intoduction to balance all ref. in the revised paper. We also narrowed self citations.
Please, verify that all figures are cited in the text. This lack of care does not reflect well on you. A suggestion on figures, consider merging figures 1-5 can in one single figure.
Comment: We corrected citations of figures in the text. We agree that a number of figures especially these with photos of trees might be compressed first to one with description of a,b,c etc. like in paper Dlugonski, Wellman, Haase 2023. (Old forest growth..., Land). Another graphical illustrations (eg. with trees growth for given case) - we also considered joining them to one synthetic illustration.
More detailed comments are listed below.
L15. Why “would have”? I assumed this has already happened, change to “have”?
Comment: Agree. We corrected.
L28. Some of these keywords are already in the title. Consider replacing them.
Comment: Agree. We corrected keywords/title.
L32-35. One sentence paragraph. Merge with the next paragraph.
Comment: Agree. We modified the paragraph.
L39. References?
Comment: Agree. We added important reference in this part.
L35. Provide just key references here. No need to cite 13 studies here.
Comment: Agree. We corrected citations and narrowed the list of citations.
L45. Provide just key references here. Do you really need 31 references for these statements?
Comment: Agree. We provided only key references here.
L46-54. This paragraph needs references.
Comment: Agree. We improved references. However, we also modified the paragraph.
L53. Anthropogenic refers to their origin, not necessarily to their durability and regulation capacity, where did you get this definition from? Reference?
Comment: Agree. We modified the paragraph.
L55. Delete “especially”.
Comment: Agree. We delated.
L60. I would say “reduce” and not “limit”.
Comment: Agree. We edited.
L65. This information in parentheses doesn’t read well here.
Comment: Agree. We improved.
L66. Something reads oddly here “new-planted trees which are failing to establish is significant”.
Comment: Agree. We improved.
L67. What do you mean by “planting mature trees”?
Comment: Wrong translation. We improved the mistake.
L79-88. References needed.
Comment: Agree. We improved missing data in corrected paper.
L118. What languages were used to search articles and other publications? How many articles were retrieved and reviewed? How many articles were used on this study? Did you have any criteria for the inclusion of articles in this study?
Comment: We mentioned the lack data in corrected methodology part of revised paper.
L139-147.More details are needed here. How many field observations? From which regions and when were these conducted? How many poplar taxa were located in urban areas and in how many locations? Provide a table showing how many studies used these different techniques. What type of analyses were used to identify this one representative cultivar?
Comment: Agree. We improved the information of selected trees in revised text.
L140. Taxa is the plural of taxon, no “taxons”.
Comment: Agree. We improved.
L182. Correct to “limited research”.
Comment: Agree. We improved.
L183. Delete “urban green spaces”.
Comment: Agree. We delated.
L185. How many studies were included here?
Comment: Agree. We completed the information in corrected version.
L190-194. But many other species can provide these benefits, this is not exclusive to poplars. I think you need to focus here on what is special or unique about poplars. That seems more relevant.
Comment: Agree. We added more benefits of poplars to accent their unique properties in cities.
L199. References?
Comment: Agree. We added important references in this part.
L202-212. This is repetitive. Some of this information has already been mentioned.
Comment: Agree. We delated the sentences which has already been mentioned in corrected verison.
L214. Figure 1 is not cited in the text.
Comment: Agree. We added the citation.
L225. Figure 2 is not cited in the text.
Comment: Agree. We added the citation.
L 233-235. It is not clear the relationship between fast growth and reduction of the urban heat island effect. Is it because cities can get more canopy cover faster? Clarify.
Comment: Agree. We clarified this aspect deaper in corrected version.
L236. What about shade?
Comment: Agree. Thank you for your suggestion here. We added this issue to main text and characterized.
L239. Figure 3 is not cited in the text.
Comment: Agree. We added the citation.
L251. Figure 4 is not cited in the text.
Comment: Agree. We added the citation.
L256. Figure 5 is not cited in the text.
Comment: Agree. We added the citation.
L269. Why is this in bold? If it is a quote, you need to add the citation.
Comment: Agree. We corrected to normal style.
L271-275. The fast growth topic has already been mentioned earlier. Group the same topics together so it doesn’t read repetitively and the reading flows better.
Comment: Agree. We deleted the repetitions in this part in corrected version. We grouped the information for reading flows better.
L280. What do you mean by “ecological adaptability”? Define for your readers.
Comment: Thank you. We defined it as possibility with dealing the climate change in the city. Poplar trees are resistant to drought and this is one of the species' abilities to survive better than other selected trees for planting in cities such as linden trees or oaks. This was added to corrected version of the paper.
L302. Provide scientific name.
Comment: OK. We improved.
L305. What are these “many interesting characteristics”?
Comment: An unfortunate twist. Thank you for noticing the inaccuracy. We improved English editing in our text.
L308-324. References needed.
Comment: Agree. We added important references here.
L318. Recommended by who?
Comment: Agree. We added the recomendation in this part.
L325-336. Is all this based on field observations? If yes, clarify, if no, add references.
Comment: Sure, agree. Of course not at all. We clarify there aspects deaper in corrected version as well as we added important references.
L337-341. This fits better in Methods.
Comment: Agree. We improved this part and we added this part to methods chapter.
L376. You cited first Figure 7 in the text. You need to update figures’ order or cited Figure 6 before.
Comment: Agree. We improved.
L377-393. This reads very repetitive. You can summarize this and present these results in a table to improve the flow of the reading.
Comment: Agree. We presented this part in a table.
L394. Who conducted these measurements?
Comment: Thank you. We added this lack of information of measurments in corrected version.
L398. Was this correlation significant? Details are needed in the text.
Comment: Thank you. We added this lack of information of significance correlation in corrected version.
L414-415. This is not mentioned in the Methods.
Comment: Agree. Thank you. We added this lack of information to methods chapter in corrected version.
L422. Define SGGW in the legend.
Comment: OK. We improved.
L425-426. Missing in Methods.
Comment: OK. We improved.
L425. Why was this tested? What are your working hypotheses?
Comment: OK. We improved.
L443. Figure 10 is not cited in the text.
Comment: Agree. We added missing information.
L461. Correct references’ format.
Comment: Agree. We corrected.
L462. When did you collect these field measurements? Missing in methods.
Comment: Agree. We added missing information.
L483. What are these “favorable conditions”? Describe for your readers.
Comment: Agree, not proper translation here. We change the meaning of the sentence.
L501. Figure 13 is not cited in the text.
Comment: Agree. We added information.
L505. What tests were used? Where is the evidence of this paragraph?
Comment: We added information.
L508. Do you mean “SIGNIFICANT increase”? Also, you need to cite a table with those results here.
Comment: We clarified in main text.
L516. Missing in Methods.
Comment: We added missing information.
L516. Delete “the strength of”.
Comment: Agree. We deleted.
L527. Why forgotten? It seems like they are being used.
Comment: Agree. We improved.
L540. What do you mean by “Adaptive re-planting strategies”? Explain for your readers.
Comment: We clarified. We mean planting new trees of the same species on the site of old varieties, an example was used in the Park in Chorzów.
L541. A mix of different poplar species or general mix of all types of urban tree species? Because we should advocate for the latter in urban settings to increase biodiversity and resilience.
Comment: We advocate to use in cities a mix of tree species but include much bigger share of various culitivars of poplars which are rather today postponed in selection. So that’s why we try to show that without poplars it’s rather hard to keep an afforestation in cities due to arising anthropopression, arising urbanisation and climate change.
L546-568. Reads repetitive; all this has been already mentioned. Delete?
Comment: We deleted the repetition.
L558. Reference?
Comment: We added.
L569-579. In this section, you repeat three times “sustainable urban development”. Make sure that you don’t repeat the same ideas and topics in different paragraphs.
Comment: Agree. We improved.
L580. This has already been mentioned above. Present the same topics together in one paragraph to avoid repetition and improve the flow of the reading.
Comment: Agree. We improved.
L587. Why “in conclusion”? This is not the end of the manuscript.
Comment: Agree. We improved.
L587-591. Again, this has already been established and mentioned multiple times.
Comment: Agree. We improved.
L595. If this is a myth and misunderstanding, then what is the point of discussing the shorten trees' lifespan in L528-583. With this statement, it seems irrelevant (or even false) everything was mentioned above.
Comment: Agree. We improved.
L596-599. Delete. It has been mentioned many times.
Comment: Agree. We improved.
L600. But in L595 you say this is a myth and misunderstanding.
Comment: Agree. We improved.
L604. This does not read as scientific language “Trees in cities live shorter and shorter”. Also, it needs a reference.
Comment: Agree. We improved.
L606. What are these species?
Comment: Agree. We improved.
L606-607. But this is not a short-lived tree considering that street trees have an average lifespan of 13-20 years. See Smith et al. 2019, Plos One.
Comment: Agree. We improved.
L613. But you haven’t defined these favorable conditions.
Comment: Agree. However, we want them be favorable so we chose the meaning of the sentence.
L624-644. This is a repetition of the results.
Comment: Agree. We improved.
L633. Very high compared to what? What is the baseline of comparison here?
Comment: Agree. We improved.
L645. Delete “In conclusion”.
Comment: agree. We delete in revised paper.
L655. What would take 24 years?
Comment: We clarify: to replace the average 100 years old tree: as mentioned in ealier sentence.
L657. What do you mean by “tree activity”? This is the first (and only) time you mention this term.
Comment: Agree. We improved the meaning.
L658. Reference for maintenance costs?
Comment: Agree. We improved.
L661. Define poor conditions.
Comment: Agree. We defined.
L677. This is the only time you refer to these as “Berlin variety”. Use the same terminology to avoid confusion.
Comment: Agree. We improved the teminology.
L681. Provide examples of these mistakes for your readers.
Comment: We are not sure that we understand your comment. This might be misunderstanding. Our data was lack of some information what we mentioned ealier, so we point out the limitations deaper in corrected version.
L703. It is possible, so I’d rephrase this and replace the word “impossible”.
Comment: Agree. We improved the meaning.
L705. Missing bracket.
Comment: Agree. We improved.
L714. There is no mention anywhere in the manuscript how many species are or at least how many species were included in this study.
Comment: Agree. We improved the information on selected taxa. The information is also visible on tables with statistics.
Reviewer 2 Report
Comments and Suggestions for AuthorsPlease see the attached.
Comments for author File: 
Comments.pdf
Moderate editing of English language required.
Author Response
We would like to thank a lot the reviewer for the comment.
This study analyzed the previous research on the poplars considering them as an useful means of improving urban green spaces. The outcomes from this research are based on the comprehensive literature review and original methodology for estimating the time series changes in poplar s growth and shape. However, the purpose and the objectives of this research are unclearly defined, and the methodological flow is not clearly explained. Although authors emphasize the four aspects of poplars importance aesthetical, ecological, economic and social significance, major questions do not deal with those four facets. Even if it is not true that poplars are short-lived, it does not mean that poplars should be planted. I believe that understanding the healthy life of this species in urban areas is one of the most important factors as well as the longevity. English and grammar through the whole text should be checked carefully.
Comment: We would like to thank the reviewer for appreciating our efforts and contribution to the selection of an original methodology for research on urban poplars. We may add here that research in the field of landscape architecture has a miltimixed methodology and wide scope, which is sometimes tedious and difficult to accurately and clearly capture in scholarly articles (especially with JCR) due to the interdisciplinary nature of our research.
We agree with all suggestions of the reviewer.
We improve the major questions to the scope of the paper to chosen selected values of trees in revised paper.
We also clarify the described purpose and obiective as well as the methodology of the reseach, as the reviewer suggested.
We also highligt the hypothesis :
"Even if it is not true that poplars are short-lived, it does not mean that poplars should be planted".
to make it more understandable and to have its justification in our and other studies in the field of landscape architecture.
We also moderate English and grammar for better understanding and flow reading the paper.
Reviewer 3 Report
Comments and Suggestions for AuthorsReview of land-2911005
The paper has the title “The potential of poplars (Populus L.) for the sustainable environment of cities”. Unfortunately, the manuscript fails to live up to a compelling set of arguments as to why and how poplars should be considered by urban foresters to be as good as, or even superior, to all the other tree species that are used in urban forestry.
I have three major issues with the paper, which I will address in this order: (1) the writing, which uses way too many generic phrases and poor choices of vocabulary; (2) the parochial nature of the main dataset relied upon to make the case for poplars in urban-forest management; and (3) the lack of comparative information to demonstrate any superiorities of poplars over trees of other genera.
The Writing
As an example of the writing deficiencies, let me dissect the abstract sentence by sentence.
“Urban environments face escalating challenges, e.g. due to uncontrolled urbanization, rapid population growth or climate changes, prompting the exploration of sustainable solutions for enhancing urban green spaces (UGS).”
This is totally generic. “or” is the wrong word – it should be “and”
“For this reason, poplars (Populus L.), due to their rapid growth, wide range adaptability to environmental conditions and versatility of use, would have emerged as very promising.”
Why “would have”? And why poplars – I would have thought that trees in general would be seen as promising to help cities face their escalating challenges.
“This comprehensive review synthesizes current knowledge regarding poplar's application in urban landscapes, emphasizing its multifaceted contributions and benefits.”
First, I don’t get the feeling that the review is adequately global – it seems focussed on eastern Europe. Second, how is it that poplars deliver multifaceted contributions and benefits any more or better than other tree genera?
“However, challenges arise from the variable lifespans of different poplar cultivars, necessitating strategic management approaches.”
Most tree genera have wide variations of tree longevity across species. It seems to me that poplars are, as a group, especially short-lived. Moreover, what is a strategic management approach such that it is necessitated by the variable lifespans of the poplar cultivars? Should urban foresters not always take a strategic management approach?
“Selecting cultivars based on growth rates, root system characteristics, and adaptability to urban conditions is pivotal.”
This is true for all tree species chosen for establishment in urban settings.
“Adaptive replanting strategies, incorporating species with varying lifespans, offer solutions to maintain continual greenery in urban landscapes.”
What are “adaptive replanting strategies”?
“Collaborative efforts between researchers, urban planners, and policymakers are essential for devising comprehensive strategies that maximize benefits while addressing challenges associated with their variable lifespans.”
This is true for all tree species chosen for establishment in urban areas.
“In conclusion, harnessing poplar's potential in urban greenery initiatives requires a balanced approach that capitalizes on their benefits while mitigating challenges.”
Same – true for all tree species.
“Further research and adaptive strategies are crucial for sustained and effective utilization in creating resilient and vibrant urban landscapes.”
This is not unique to poplars, nor to urban forestry.
It is not feasible for me to undertake similar analysis of diverse passages in the paper’s main text. I am an English-mother-tongue researcher and I look for crisp and correct expression in a scientific paper. This manuscript contains numerous errors of expression, fact, and meaning. Here are just a few more examples:
Lines 46-47 – “urban green spaces” are contrasted with “natural forests” – this is a false contrast because not all urban green spaces are dominated by trees. Many are dominated by wetland vegetation and mown grass.
Lines 51-52 – “However, to fulfill their much-expected functions effectively, urban green spaces (UGS) must be adequately designed, maintained, and protected for years.” This is a truism and adds nothing to the discourse here.
Lines 52-54 – “UGS are largely anthropogenic, meaning their durability and self-regulation capacity are limited compared to natural ecosystems” – no evidence is provided to substantiate this strong claim.
The Data
This paper should be about the use of poplars in cities worldwide, or even continent-wide. The literature review is global, but the data assembled are for a few settings in two Polish cities. I don’t see the relevance of the photos (Figures 1-5), all of which portray different settings from the two streets mentioned in the methods under the third section. Any datasets brought into this paper should have far greater spatial applicability than a couple of streets in a couple of cities.
The Advantages and Disadvantages of Poplars
This topic can only be addressed properly if comparisons are made with tree species of other genera and how they perform compared to poplars. The questions should be these: (1) are poplars better than other tree species used in urban settings when it comes to the wide range of ecosystem services; and (2) are poplars worse than other tree species when it comes to ecosystem disservices. The manuscript hardly scratches the surface of these inter-genera comparisons. For example, let us take growth rates. How much faster do poplars grow than other tree species in urban settings? This needs to be examined both in terms of height increment (assuming that early height increment is important to people) and biomass accumulation. The biomass must be measured in terms of dry weight/unit area, not volume/area, because poplar is among the lightest woods of temperate species on a dry-weight basis.
Then, let’s examine damage from roots. I do not believe that poplars do more-extensive damage to surface infrastructure such as sidewalks, curbs, and roadways than all the other urban tree species. All tree species are shallow-rooted in the sense that the majority of their roots are close to the ground surface – the key is that some species are also deeply rooted and thus have superior stability during wind events. I have seen extensive urban infrastructure damage from trees of all species.
There is no discussion of the appropriateness of foreign-derived poplar cultivars in urban settings from a biodiversity perspective. Just because some poplar species are native to the ecoregion where a specific city is located does not mean that any poplars – species or cultivars – are appropriate to add to the palette of planted trees when it comes to supporting native biodiversity. An example of this relates to the proliferation of Norway maple (a European species) into North America where there are already many species of native maples chosen for urban plantings. The Norway maples are not only invasive, but they contribute next to nothing when it comes to provision of habitat for native species of intertebrates and vertebrates.
Conclusion
The ambition of the authors to develop an argument for the careful expansion of the use of poplar species in temperate-zone urban settings is laudable and worthwhile. The current manuscript is not acceptable for publication, even with substantial revisions. I recommend that the authors be invited to start over again and fashion a compelling story in favour of poplars in cities. The story would be much shorter, and would:
(a) Favour tight arguments about the potential superiority of poplars over other species choices;
(b) Carefully document the reasons to be cautious about having too much poplar in the total mix of trees in the urban forest;
(c) Dispense with the details of the local case studies – they add little to the broader storyline.
I recommend that an English-mother-tongue researcher be added to the suite of authors so that the rhetoric can hold up under logical and empirical scrutiny by international reviewers.
Comments on the Quality of English LanguageSee my responses to the authors. The paper has numerous errors of vocabulary and correct English expression.
Author Response
We would like to thank a lot the reviewer for the comment.
The paper has the title “The potential of poplars (Populus L.) for the sustainable environment of cities”. Unfortunately, the manuscript fails to live up to a compelling set of arguments as to why and how poplars should be considered by urban foresters to be as good as, or even superior, to all the other tree species that are used in urban forestry.
Comment:
Thank you very much for your valuable attention. However, tree planting in Polish cities is not decided by people representing urban forestry, but by local authorities or plenipotentiaries such as planners, urban planners and landscape architects, who use the standards for shaping green spaces of cities of Warsaw to select species for specific locations (Borowski et al 2016 Stabdardy...). It should be noted that poplars are not new species to the city. They were successfully tried in cities in 20C, but due to their fragility and poor sanitation, they were largely displaced by other species such as clones (mainly Acer campestre) and linden trees. These, however, cannot be used as the only species because they no longer cope as well with climate changes and temperature fluctuations (El Niño 2024) as shown by the latest research e.g. by the urban ecology team from HU Berlin and UFZ Leipzig and colleagues from Leipzig or Berlin (East Germany) and thus a similar climate zone to the Polish one. We therefore believe that it is necessary to return to the old proven varieties, which can successfully achieve rapid growth and survive up to 100 years in difficult urban conditions, as evidenced by the individual trees preserved in Warsaw, for example, which we characterize in the paper. However, after 60 years they should be replaced which is clear e.g. In the Czech Republic or Germany and other countries of Western Europe, but unfortunately in Poland, the practice is not adopted due to the misperceived trend (mainly by the scientific community and the government) of the so-called "civilization of the environment". Pseudo protection of trees especially by the elderly mainly residents of the capital. We therefore wanted to strengthen this aspect. It is therefore necessary to return to the old varieties but also to good practices including care procedures and monitoring of trees. It seems to us that if the research is to have the form of novelty, we would like to emphasize the importance and role of poplars as a forgotten but worth noting species (which has its justification in the historical sources that we cite). Otherwise, there is such a risk that there will be monocultures of plants in cities. It is worth noting that modern studies approve as the best only 3 species, i.e. some selected linden (Tilia ‘Euchlora‘) clones (Acer camestre) and pears variety for cities (Pyrus 'Chanticleer'), which do not necessarily grow esp. during summer seazon (due to eg. drought) and are quite monotonous for new plantings in cities, especially on roads or park alleys. What is more, it is necessary to reproduce species that were previously planted in historical places, which we also write about and emphasize more strongly in the revised paper. However, we realize that these arguments are poorly described and require better argumentation for. In our work we focus on historical alleys by the road or in a park with 20C, and the work itself does not concern urban forestry (for example, Las Bielański in Warsaw). Hence the valuable comment of the reviewer, for which we thank you again. We realize that this is our view on the selection of old species for the city and not everyone has to agree with it, but we should definitely emphasize these threads in the discussion in the revised paper which we have improved.
I have three major issues with the paper, which I will address in this order: (1) the writing, which uses way too many generic phrases and poor choices of vocabulary; (2) the parochial nature of the main dataset relied upon to make the case for poplars in urban-forest management; and (3) the lack of comparative information to demonstrate any superiorities of poplars over trees of other genera.
The Writing
As an example of the writing deficiencies, let me dissect the abstract sentence by sentence.
“Urban environments face escalating challenges, e.g. due to uncontrolled urbanization, rapid population growth or climate changes, prompting the exploration of sustainable solutions for enhancing urban green spaces (UGS).”
This is totally generic. “or” is the wrong word – it should be “and”
Comment:
Thank you for your valuable attention. We agree. We have improved the writing style, vocabulary and grammar in the revised paper. We improve dataset as well as highlight benefits of poplars eg. rapid growth as well as rapid biomass growth and shading, which is especially relevant on hot days. Other species grow slower, so the ultimate benefit for human well-being is also long-term until maturity. We have highlighted these threads more strongly in the revised Paper. In addition, we have corrected the text. The general sentences have been clarified strongly in the work and supported by the relevant literature.
“For this reason, poplars (Populus L.), due to their rapid growth, wide range adaptability to environmental conditions and versatility of use, would have emerged as very promising.”
Why “would have”? And why poplars – I would have thought that trees in general would be seen as promising to help cities face their escalating challenges.
Comment:
We agree. This was the case in 20C when poplars were selected for planting in new arteries or settlements. However, now in 21C poplars are not judged because the experience in previous years mainly lack of care led to many disasters but mainly due to the human factor and lack of proper care. Of course, poplars have their drawbacks, e.g. brittle wood and brittleness. We understand that. However this is not a reason to completely exclude them from new plantings in cities. Thus, by relying largely on these past mistakes, this kind of problem can be avoided in the future. We emphasised this issue strongly in the revised paper.
“This comprehensive review synthesizes current knowledge regarding poplar's application in urban landscapes, emphasizing its multifaceted contributions and benefits.”
First, I don’t get the feeling that the review is adequately global – it seems focussed on eastern Europe. Second, how is it that poplars deliver multifaceted contributions and benefits any more or better than other tree genera?
Comment:
We agree. Of course this is true, because some varieites of poplars (eg. balsamic) were often planted in specisic climate zone like in Eastern or Southern Europe, as example of Poland. Thus, the topic seems to be local, not global. They are not as demanding as other species and sensitive to water shortages. We describe a case study that has a local character because it concerns our climate zone and Polish problems with urban green management, which is poorly described in the literature of the subject internationally. Thus, it is hard to find a similar taxidermist on a global scale, because we have many zones and different species all over the world, and in this way we have equal environmental problems. It seems to us that it is difficult to approach the problems globally in this case. We clarified the literature going beyond Polish studies (as much as possible), and also clarified sentences with too general meaning in the revised paper.
“However, challenges arise from the variable lifespans of different poplar cultivars, necessitating strategic management approaches.”
Most tree genera have wide variations of tree longevity across species. It seems to me that poplars are, as a group, especially short-lived. Moreover, what is a strategic management approach such that it is necessitated by the variable lifespans of the poplar cultivars? Should urban foresters not always take a strategic management approach?
Comment:
Yes, we agree. However, such dilemmas should be included in legal documents and studies of specialists such as standards for shaping green areas....(Borowski et al 2016). Since the tree lives shorter it should be replaced faster and this should be known especially in Poland mainly decision-makers and so local officials not necessarily foresters who, as we mentioned earlier, do not decide about trees on the streets of the city as in Warsaw or in Chorzów in the area of the city park. However, this is not common practice and such standards have been developed successively for an increasing number of cities in Poland only for a few years. It seems that managers know more and more thanks to these studies, which is why many mistakes from the past can be avoided, and how it is better to choose the species of trees, including forgotten poplars discussed by us, to specific requirements in the city (difficult conditions) or historical conditions, which we also emphasized in the revised paper.
“Selecting cultivars based on growth rates, root system characteristics, and adaptability to urban conditions is pivotal.”
This is true for all tree species chosen for establishment in urban settings.
Comment:
Sure, we agree. However poplars are one example of such species, and there is relatively little research on the benefits of these trees in the urban tree literature compared to other species that are approved in cities by various scientific communities. We emphasised the positive significance of poplars more strongly in the text and less emphasising general statements.
“Adaptive replanting strategies, incorporating species with varying lifespans, offer solutions to maintain continual greenery in urban landscapes.”
What are “adaptive replanting strategies”?
Comment: Agree. We are writing about the adaptation of plants to changing climatic conditions, e.g. droughts, floods, hurricanes, e.g. Eunice. We refined the meaning of the sentence in the revised paper.
“Collaborative efforts between researchers, urban planners, and policymakers are essential for devising comprehensive strategies that maximize benefits while addressing challenges associated with their variable lifespans.”
This is true for all tree species chosen for establishment in urban areas.
Comment:
Agree. This is about the necessity and benefits of the cooperation of people (different entities including specialists) which in Polish conditions is difficult to achieve due to loopholes in the law and constant changes, which we also wrote about earlier. We will clarify the meaning of the sentence in the revised version.
“In conclusion, harnessing poplar's potential in urban greenery initiatives requires a balanced approach that capitalizes on their benefits while mitigating challenges.”
Same – true for all tree species.
Comment:
Yes, we agree. However, it is clear that some of the issues raised in the paper are common to all trees as their overall benefit to the urban environment and human well-being. We have refined these issues in a revised paper.
“Further research and adaptive strategies are crucial for sustained and effective utilization in creating resilient and vibrant urban landscapes.”
This is not unique to poplars, nor to urban forestry.
Comment: We agree. We now understand that we should emphasize the value of the poplar species itself more strongly to show its superiority over other species. We have refined these issues in a revised paper.
It is not feasible for me to undertake similar analysis of diverse passages in the paper’s main text. I am an English-mother-tongue researcher and I look for crisp and correct expression in a scientific paper. This manuscript contains numerous errors of expression, fact, and meaning. Here are just a few more examples:
Lines 46-47 – “urban green spaces” are contrasted with “natural forests” – this is a false contrast because not all urban green spaces are dominated by trees. Many are dominated by wetland vegetation and mown grass.
Comment:
Thank you very much for your thorough analysis of the shortcomings of our pape. We understand that certain terms or phrases need to be corrected as they may introduce ambiguity. These comments have been taken into account directly in the text of the revised paper.
Lines 51-52 – “However, to fulfill their much-expected functions effectively, urban green spaces (UGS) must be adequately designed, maintained, and protected for years.” This is a truism and adds nothing to the discourse here.
Comment: We partly agree. We guess that maybe in other european countries (which we also observe for example in Western Europe or the Czech Republic) this is generally accepted knowledge and maybe truism. In Polish practice the appropach to this issue is unfortunately different. We have many examples of erroneous decisions about the life of poplars because designers and specialists are not involved in this process, e.g. landscape architecture. Very often, decision-makers do not have a faint idea about trees. Hence their miserable fate and problems, which we also describe in the paper ("tree in the city is the enemy" is an accepted practice unfortunately for many years, although it is beginning to change little by little). We believe that especially these decision-makers should be made aware, but also residents. We have many good examples of education in this area for several years in Poland confirming that making people aware of these aspects has positive effects. People began to appreciate nature, especially in Central Poland, for example in Warsaw or Łódź (the two largest Polish cities). In Chorzów there is a horticultural tradition supported by German influences from the times of the Partition. We will highlight this topic more strongly in the revised paper. We consider also adding important literature on stakeholders attendence in planing proces of new trees planting (Afzalan N et al 2014. The Role of Social Media in Green Infrastructure Planning…DOI:10.1080/10630732.2014.940701)
Lines 52-54 – “UGS are largely anthropogenic, meaning their durability and self-regulation capacity are limited compared to natural ecosystems” – no evidence is provided to substantiate this strong claim.
Comment: Thank you. We will support this argument in the text of the revised paper.
The Data
This paper should be about the use of poplars in cities worldwide, or even continent-wide. The literature review is global, but the data assembled are for a few settings in two Polish cities. I don’t see the relevance of the photos (Figures 1-5), all of which portray different settings from the two streets mentioned in the methods under the third section. Any datasets brought into this paper should have far greater spatial applicability than a couple of streets in a couple of cities.
Comment: Thank you for your valuable comments.
However, as we mentioned earlier, the global aspect seems difficult to illustrate, especially since we present a local problem supported by earlier data from Poland on two examples of cities where poplars were planted in 20C or renewed in 21C. We do not have data from the continent of Europe or the world. However, we can emphasize our methodology more strongly so that the described preliminary study has its application in similar studies, and other scientific communities can draw knowledge from our studies if they want to do their analyses on similar case studies (if they do not have their own developed methodology). We think these are important issues for the novelty and applications of the article research. We will emphasise these aspects more strongly in the text.
The Advantages and Disadvantages of Poplars
This topic can only be addressed properly if comparisons are made with tree species of other genera and how they perform compared to poplars. The questions should be these: (1) are poplars better than other tree species used in urban settings when it comes to the wide range of ecosystem services; and (2) are poplars worse than other tree species when it comes to ecosystem disservices. The manuscript hardly scratches the surface of these inter-genera comparisons. For example, let us take growth rates. How much faster do poplars grow than other tree species in urban settings? This needs to be examined both in terms of height increment (assuming that early height increment is important to people) and biomass accumulation. The biomass must be measured in terms of dry weight/unit area, not volume/area, because poplar is among the lightest woods of temperate species on a dry-weight basis.
Comment: Thank you for your valuable insights. We will include the correction of sudial-research questions directly in the text. We also highlighted in the revised paper the advantage of poplars in cities over other tree species for alley plantings more strongly. We have refined the article for better argued the issue.
Then, let’s examine damage from roots. I do not believe that poplars do more-extensive damage to surface infrastructure such as sidewalks, curbs, and roadways than all the other urban tree species. All tree species are shallow-rooted in the sense that the majority of their roots are close to the ground surface – the key is that some species are also deeply rooted and thus have superior stability during wind events. I have seen extensive urban infrastructure damage from trees of all species.
Comment: We agree. The roots and the issue was described in Piasecki (1974). What is also imtersuting here the problem of lifting paving slabs by tile root system was already known in the 70s 20C. We agree with the reviewer that the root system of these trees is similar to that of other trees. We have highlighted the problem of using permeable surfaces. The thing is, not all designers' decisions are right. Finally, giving examples of good practices, new plantings of trees will live in the city longer.
There is no discussion of the appropriateness of foreign-derived poplar cultivars in urban settings from a biodiversity perspective. Just because some poplar species are native to the ecoregion where a specific city is located does not mean that any poplars – species or cultivars – are appropriate to add to the palette of planted trees when it comes to supporting native biodiversity. An example of this relates to the proliferation of Norway maple (a European species) into North America where there are already many species of native maples chosen for urban plantings. The Norway maples are not only invasive, but they contribute next to nothing when it comes to provision of habitat for native species of intertebrates and vertebrates.
Comment: Yes, we agree. Thank you for your suggestions.However the biodiversity aspects is out of scope in our paper. As we mention we chose one taxa and decide to desribe the issue due to historical and tres background as well as benefits for given species. However, if we chose poplars than monokultury (as we mention ealier) in the cities we increase the biodiversity. We think this might be a good start point to face the problem and find trade-offs of the issues we discussed.
Conclusion
The ambition of the authors to develop an argument for the careful expansion of the use of poplar species in temperate-zone urban settings is laudable and worthwhile. The current manuscript is not acceptable for publication, even with substantial revisions. I recommend that the authors be invited to start over again and fashion a compelling story in favour of poplars in cities. The story would be much shorter, and would:
(a) Favour tight arguments about the potential superiority of poplars over other species choices;
(b) Carefully document the reasons to be cautious about having too much poplar in the total mix of trees in the urban forest;
(c) Dispense with the details of the local case studies – they add little to the broader storyline.
I recommend that an English-mother-tongue researcher be added to the suite of authors so that the rhetoric can hold up under logical and empirical scrutiny by international reviewers.
Comment: We agree, we improve revised paper. We start over again and correct some parts of the text that their meaning might be not understandable or mythic. We also used english softwere editing support for improving the paper.
Reviewer 4 Report
Comments and Suggestions for AuthorsGreenspace is an important component of urban nature, providing vital ecosystem services to society and protecting human health. The paper focuses on the application value of poplar trees in urban areas. It begins by reviewing the knowledge of poplar trees in the urban landscape, including their ecological characteristics, the ecosystem services they provide, and their main shortcomings. Then, woodlot forms consisting of various poplar taxons located in urban areas of various locations was observed on the spot. The MS focuses on the SDG issue at a regional level. Generally, the MS can fall within the scope of the journal. The MS was structured logically. However, there are still several minor questions before it can be accepted for publication.
1. This paper does not sufficiently discuss the potential ecological risks and strategies associated with poplar trees. Current reviews have only focused on the issue of their short lifespan. It is suggested that other defects, such as pests, shallow root systems, and cottony seeds, be included in the review and discussion sections. In some Asian countries, the cottony seeds of poplar trees significantly limit their use.
2. Conclusion Part. the paragraph should be further condensed to provide theoretical findings by summarizing individual case results.
Author Response
Greenspace is an important component of urban nature, providing vital ecosystem services to society and protecting human health. The paper focuses on the application value of poplar trees in urban areas. It begins by reviewing the knowledge of poplar trees in the urban landscape, including their ecological characteristics, the ecosystem services they provide, and their main shortcomings. Then, woodlot forms consisting of various poplar taxa located in urban areas of various locations was observed on the spot. The MS focuses on the SDG issue at a regional level. Generally, the MS can fall within the scope of the journal. The MS was structured logically. However, there are still several minor questions before it can be accepted for publication.
We would like to thank a lot the reviewer for the comment.
- This paper does not sufficiently discuss the potential ecological risks and strategies associated with poplar trees. Current reviews have only focused on the issue of their short lifespan. It is suggested that other defects, such as pests, shallow root systems, and cottony seeds, be included in the review and discussion sections. In some Asian countries, the cottony seeds of poplar trees significantly limit their use.
Comment:
Thank you very much for your valuable suggestions. This valuable comment of the reviewer and our thoughts have been included in the revised paper. Unfortunately, we are not able to discuss all issues of poplars in one manuscript. First of all, it requires inviting a larger number of specialists (e.g. experts on pests, migrobiologists or people related to phytotherapy). In spite of the fact our research is interdisciplinary, each of the authors deals with different issues, e.g. growth or durability and aesthetic values of trees in green areas. Of course, we certainly developed some issues (e.g. roots or cotton problems – also visible in polish examples, which is associated with light nuisances) much more strongly. However, more threads are not included becuse they might cover the main threads which are the ecological benefits of poplars in cities.
- 2. Conclusion the paragraph should be further condensed to provide theoretical findings by summarizing individual case results.
Comment:
Thank you for your valuable suggestions. We have refined this chapter into more theoretical issues which will be supported by our findings.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors,
Thank you for responding and addressing all my previous comments. Your manuscript has improved considerably. I have no further comments to make.
Comments on the Quality of English Language
Minor mistakes need to be revised before publication.
