Climate Strengthens the Positive Effects of Stand Structure on Understory Plant Diversity in Chinese Temperate Forests

Response to Reviewer 1 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. We have revised our previously-submitted manuscript entitled “Climate strengthens the positive effects of stand structure on understory plant diversity in Chinese temperate forests” (forests-2655997) by carefully following the comments. Many thanks to the you and your thoughtful suggestions. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

In this revision, we have responded to each of the issues raised by the reviewers to improve both the scope and expression of the work. The major changes in the current revision are as follows:

i) We read the MDPI requirements on citations in the text and references in detail, and then made careful revisions both in the text and Reference list.

ii) We have made a thorough and detailed revision of the Introduction to make this part more concise and accurate. We have deleted a section of the Introduction and adjusted the order of sentences in the Introduction.

iii) We have added an overview of the data set time in the Methods. Although the start and end times of the three data sources are inconsistent, we selected data from the same time period during data filtering, that is, data from 2014 to 2018. We added this statement in the data filtered section.

iv) We are very sorry for our grammatical problems. After the manuscript was written, we polished it by Leonie Seabrook, PhD, from Liwen Bianji (Edanz) (http://www.liwenbianji.cn). We mentioned in the acknowledgments section of the original manuscript. The relevant proof can see below. However, after the polishing was completed, we made partial revisions to the manuscript, which may have caused inaccurate language expression in a certain part of the manuscript. In view of this, we handed over the revision to English-related practitioners for revision.

We believe that the revised manuscript is in a much better form by focusing on the major findings and by improving the writing. Detailed responses to specific comments are listed Point-by-point response to Comments.

Many thanks to the editors and reviewers again. We hope that we have addressed all of your concerns and that the revision is now acceptable for the publication.

2. Point-by-point response to Comments and Suggestions for Authors

Comments 1: ["Line 16: This sentence has no practical meaning."]

Response 1: Thanks for your comments. We now removed the sentence.

Comments 2: ["Line 36-37: interact with one another in the forest environment? Confused."]

Response 2: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 3: ["Line 41: which accounts for most of plant diversity? Confused."]

Response 3: Thanks for your comments. We deleted it because it confused and no practical meaning.

Comments 4: ["Line 50-53: long sentence. Unclear."]

Response 4: Thanks for your comments. We rewrote the sentence.

Comments 5: ["Line 56-58: Unclear. More explanations are needed here. And i.e."]

Response 5:  Thanks for your comments. We rewrote the sentence. Please see Line 49-53.

Comments 6: ["Line 59-61: this sentence is illogical."]

Response 6: Thanks for your comments. We rewrote the sentence.

Comments 7: ["Line 62: focal point. Be clear."]

Response 7: Thanks for your comments. We rewrote the sentence.

Comments 8: ["Line 63: What is this sentence trying to express? What are the disparate findings?"]

Response 8:  Thanks for your comments. We deleted it because it has no practical meaning.

Comments 9: ["Line 75: these issues? Be clear."]

Response 9: Thanks for your comments. We rewrote the sentence.

Comments 10: ["Line 75-88: this paragraph is abundant and illogical. Some sentences are fragmentation."]

Response 10: Thanks for your comments. We deleted this paragraph.

Comments 11: ["Line 89: this sentence was incomplete. Be clear."]

Response 11: Thanks for your comments. We rewrote the sentence.

Comments 12: ["Line 93-94: The first two hypotheses have been fully proven. Think about it, what question the author wants to answer."]

Response 12: Thanks for your comments. We rewrote the sentence.

Comments 13: ["Line 93-97, and Fig 1: What is the basis for your assumptions or conceptual models?"]

Response 13: Thank you for pointing us to this shortcoming. We think that this is a great idea and agree that it would increase the understanding of our experimental set up. We have reworked the explanation in the Introduction and also adjusted the order of the introduction. In general, our entire introduction is to introduce two hypotheses and prove the rationality of the sum of the two hypotheses. On the other hand, even if the first hypothesis is well researched, judging from the structure of our article, the first hypothesis is the basis of the second hypothesis and is an indispensable part of the article.

Comments 14: ["Line 98-104: What is the basis for your assumptions?"]

Response 14: Thanks for your comments. We rewrote the sentence.

Comments 15: ["Line 127: the first assumption is fake. Same to line 93-94."]

Response 15: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 16: ["Line 134: functional group?"]

Response 16: Thanks for your comments. We clarify and rewrote this sentence.

Comments 17: ["Line 168: unclear."]

Response 17: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 18: ["Line 170: status? What does it mean?"]

Response 18: Thanks for your comments. We deleted “status‘.

Comments 19: ["Line 171 and throughout the MS: ha2."]

Response 19: Done.

Comments 20: ["Line 185: remove the table 1 to supplement."]

Response 20: Done.

Comments 21: ["Line 208: ha-1."]

Response 21: Done.

Comments 22: ["Line 220: niche diversity."]

Response 22: Done.

Comments 23: ["Line 222-223: long sentence. Confusing."]

Response 23: Thanks for your comments. We rewrote the sentence.

Comments 24: ["Line 231: same to line 220."]

Response 24: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 25: ["Table 2: the unit of PAR."]

Response 25: Done.

Comments 26: ["Line 290 and line 292: understory woody and herbaceous plant?"]

Response 26: Done.

Comments 27: ["Line 293: herbaceous diversity?"]

Response 27: Done.

Comments 28: ["Line 289-315: the statistical report and related value (e.g., standardized coefficient from SEM) should be provided in your text."]

Response 28: Thanks for your comments. In the final model, all path coefficients are significant (p < 0.05). Therefore, we did not add the p values of all paths one by one. Correspondingly, we added a significant statement about the path coefficient of the model in the last part of Result 3.1.

Comments 29: ["Line 298-303: the MAP increased A-Tree?  Confusing. There is an impact between the two variables, and it does not mean that one increases the other."]

Response 29: Thanks for your comments. We rewrote the sentence.

Comments 30: ["Line 328-329: confusing and unclear."]

Response 30: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 31: ["Line 351: life form?"]

Response 31: Thanks for your comments. We rewrote the sentence.

Comments 32: ["Line 361: controlled?"]

Response 32: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 33: ["Line 422: unclear."]

Response 33: Thanks for your comments. We rewrote the sentence.

Comments 34: ["Line 422: only also?"]

Response 34: Thank you for pointing us to this shortcoming. We rewrote the sentence.

Comments 35: ["Line 453-455: the conclusions are actually limited, only covering temperate zones."]

Response 35: Thanks for your comments. We rewrote the sentence.

Comments 36: ["Line 455: the study findings?"]

Response 36: Thanks for your comments. We rewrote the sentence.

Comments 33: [" References are incomplete."]

Response 33: We are very sorry for the Citation problems in the original manuscript. We read the MDPI requirements on citations in the text and references in detail, and then made careful revisions in each citation in the whole text.

Response to Reviewer 2 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. We have revised our previously-submitted manuscript entitled “Climate strengthens the positive effects of stand structure on understory plant diversity in Chinese temperate forests” (forests-2655997) by carefully following the comments. Many thanks to you and your thoughtful suggestions. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

In this revision, we have responded to each of the issues raised by you to improve both the scope and expression of the work. The major changes in the current revision are as follows:

i) We read the MDPI requirements on citations in the text and references in detail, and then made careful revisions both in the text and Reference list.

ii) We have made a thorough and detailed revision of the Introduction to make this part more concise and accurate. We have deleted a section of the Introduction and adjusted the order of sentences in the Introduction.

iii) We remove the Table 1 to Supplement Information according reviewer 1.

iv) We are very sorry for our grammatical problems. After the paper was written, we polished it by Leonie Seabrook, PhD, from Liwen Bianji (Edanz) (http://www.liwenbianji.cn). We mentioned in the acknowledgments section of the original manuscript. The relevant proof can see below. However, after the polishing was completed, we made partial revisions to the manuscript, which may have caused inaccurate language expression in a certain part of the manuscript. In view of this, we handed over the revision to English-related practitioners for revision.

We believe that the revised manuscript is in a much better form by focusing on the major findings and by improving the writing. Detailed responses to specific comments are listed Point-by-point response to Comments.

Many thanks to the editors and reviewers again. We hope that we have addressed all of your concerns and that the revision is now acceptable for the publication.

2. Point-by-point response to Comments and Suggestions for Authors

Comments 1: ["The introduction shows knowledge of the current literature, but mostly the statements are very general and not very concise, e.g. line 66 - 73: how climate directly affects stand structure?, how understory vegetation development may differ because of stand structure under similar climates and site conditions? how climate indirectly affects light transmittance? how stand structure govern interspecies relationships?"]

Response 1: We are thankful for the comprehensive and encouraging evaluation of our manuscript. Those comments are valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We describe how climate affects stand structure and how stand structure modulates interspecific relationships in the understory. In addition, we deleted a paragraph that had no actual meaning and changed the word order of other paragraphs

Comments 2: ["Figure 1. Setting the climatic regions studied in the figure and reducing them by a single gradient (representation on one axis) seems to me an oversimplification. Climate is made up of many variables (of which the authors are aware) that often change in opposite directions in different regions."]

Response 2: Thank you for your comments concerning our manuscript. Those comments are valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. Here, we make it clear that the climate zones in Figure 1 represent the comprehensive effects of climate factors. In fact, there are many climate variables. Although in the methods section of the paper, we selected 6 climate factors. But we believe that six climate factors are not enough to represent all climate effects. After extensive discussions, we believe that climate zones can reflect the comprehensive effects of climate in more detail, so in the initial hypothesis and Figure 1, we use climate zones as the main basis for dividing climate gradients. Additionally, in our hypotheses we focus on gradient changes in climate. Further, we focus on gradient changes in climate integration. Climate zones can well reflect the gradient changes in the comprehensive effects of climate, because the thresholds of multiple climate variables are considered when delimiting climate zones. Finally, our study proved that different climate variables (climate variables after PCA selection) directly or indirectly affect understory vegetation diversity. However, we did not consider the interaction effects of these climate variables because we believed that the variables selected by PCA or the interaction effects of these variables were not enough to represent the comprehensive effect of climate on understory vegetation diversity. In the second part, we focused on the effect size of stand structure in different climate zones (i.e., the combined effect of climate). In general, in the first and second parts of the paper, we believe that climate zones can better represent the comprehensive effects of climate.

Comments 3: ["Line 211-213, 234-236. A more detailed description of how the SSCI was calculated and what data was used to calculate it is needed."]

Response 3: We thank the reviewer for the suggestion. We clarified that the data source of the stand structure complexity index (SSCI) comes from Ehbrecht et al. [13,28]. We did not perform calculations based on Ehbrecht et al (2017; 2021) algorithm.

Response to Reviewer 2 Comments

1. Summary

Thank you very much for taking the time to review this revision. We have revised our previously-submitted revision entitled “Climate strengthens the positive effects of stand structure on understory plant diversity in Chinese temperate forests” (forests-2655997) by carefully following the comments. Many thanks to you and your thoughtful suggestions. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

In this revision, we have responded to each of the issues raised by you to improve both the scope and expression of the work. The major changes in the current revision are as follows:

i) We have added an explanation about climate region in the text between Line 75 and 76.

ii) We further modified the expression about SSCI in the paper, please see Line 199-200.

We believe that the revised manuscript is in a much better form by focusing on the major findings and by improving the writing. Detailed responses to specific comments are listed Point-by-point response to Comments.

Many thanks to the editors and reviewers again. We hope that we have addressed all of your concerns and that the revision is now acceptable for the publication.

2. Point-by-point response to Comments and Suggestions for Authors

Comments 1: ["1. The Introduction was satisfyingly improved. In the present form it is concise and more informative."]

Response 1: We are thankful for the comprehensive and encouraging evaluation of our manuscript. We would also like to acknowledge your work and dedication invested—it helped us to thoroughly improve the quality of our manuscript.

Comments 2: ["I understand authors point that climate is complex effect of various factors but can be simplified as a gradual changes in space. In my opinion such explanation should be placed in the text for example between line 75 and 76."]

Response 2: We thank the reviewer for their constructive and insightful comments. We have added an explanation in the text between line 75 and 76.

Comments 3: ["It is still unclear how the stand structural complexity index was obtained. In the text authors wrote: “… we defined seven stand structure variables, including stand density …, stand basal area…, mean DBH …, tree size variation…, tree height variation …, and the stand structural complexity index (SSCI) which aimed to quantify the distribution of canopies in three-dimensional space (from Ehbrecht et al. [13,28])”. The word “defined” is not precise enough.

In the response to revive authors wrote: “We clarified that the data source of the stand structure complexity index (SSCI) comes from Ehbrecht et al. [13,28]. We did not perform calculations based on Ehbrecht et al (2017; 2021) algorithm.

Ehbrecht, M., Schall, P., Ammer, C., Seidel, D. Quantifying stand structural complexity and its relationship with forest management, tree species diversity and microclimate. Agricultural and Forest Meteorology 2017, 242, 1-9. [CrossRef]

Ehbrecht, M.; Seidel, D.; Annighöfer, P.; Kreft, H.; Köhler, M.; Zemp, D. C.; Puettmann, K.; Nilus, R.; Babweteera, F.; Willm, K.; WT AL. Global patterns and climatic controls of forest structural complexity. Natural Communications 2021, 12(1), 519. [CrossRef]”

It means that the stand structural complexity index (SSCI) was not measured on the study plots examined in the study presented in the paper. Fist cited article show the SSCI measured in various climatic zones but not one in Northeast and North China. The second one present results for German forests. If I’m right, the SSCI was not measured directly on the study plots so it can not be included in to Result section. In such case the entire paper should be rewritten. The SSCI must be excluded from result section. Fortunately, other plot characteristics were calculated on the original data measured in the field and it is material good enough for the valuable paper."]

Response 3: We are thankful for the comprehensive and encouraging evaluation of our manuscript.

We deeply understand that you raised this question for the sake of the rigor of our paper. Now we explain the SSCI data acquisition and application as follows. We provided two references in our initial reply.

Ehbrecht, M., Schall, P., Ammer, C., Seidel, D. Quantifying stand structural complexity and its relationship with forest management, tree species diversity and microclimate. Agricultural and Forest Meteorology 2017, 242, 1-9. [CrossRef]

Ehbrecht, M.; Seidel, D.; Annighöfer, P.; Kreft, H.; Köhler, M.; Zemp, D. C.; Puettmann, K.; Nilus, R.; Babweteera, F.; Willm, K.; WT AL. Global patterns and climatic controls of forest structural complexity. Natural Communications 2021, 12(1), 519. [CrossRef]

The first document proposed the definition of SSCI and gave the calculation method. Based on the first article, the author of the paper and his team integrated the data to produce a global data product for SSCI (see Figure 1 and Figure2). We downloaded the data on from https://zenodo.org/records/4295910, and then used the ArcGIS value extraction to point function to obtain the SSCI value on our site. Finally, we use the extracted values for further analysis. However, due to our expression problems, it has caused problems in data acquisition and application of SSCI.

We further modified the expression about SSCI in the paper, please see Line 199-200. Thank you again for your rigorous and meticulous review. We hope that this change can be formally accepted.

Figure 1 Global patterns of stand structural complexity index.