Changes in the Number of Vascular Plant Species during Reforestation of Clearcut Forests

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study compares changes in the number of vascular plants during reforestation of clearcut forests in boreal forests and the researchers show that the species richness is highest after clearcutting and decreases with succession stages from clearcuts through young stand to middle-aged stand and old-growth forest that has the lowest total diversity. Meanwhile, they show that the mean number of vascular plant species is higher at the clearcut stage than that at the old-growth stage, and the mean number of vascular species increases with soil fertility. They conclude that the changes in the number of vascular species can be due to variation in ecotope (or soil fertility) and tree layer, as well as the fact that the study was conducted in areas close to settlements and agricultural areas.

Generally, I find the paper well written and prepared, and I think this could interest a wide audience. I don’t have major concerns and only have a few minor comments that I hope the authors find helpful to improve their manuscript.

Line 38-40: numbers add up to 104%.

Line 156: provide the information of the PC-ORD program. Version, name of the supplier etc.

Line 184: Letters above the third column of Figure 4 (P.s. – V.m.) seem incorrect. Why do they start with “ac” instead of “a”?

Line 261: Figure 261 label for axis 2 is missing. Is there any scaling on each axis?

Line 281: “ecological area”?

Comments on the Quality of English Language

Well written and easily understandable.

Author Response

We are grateful to the reviewer for the valuable comments that improved the article. Following are responses to specific comments.

Line 38-40: numbers add up to 104%. Corrected.

Line 156: provide the information of the PC-ORD program. Version, name of the supplier etc. Added.

Line 184: Letters above the third column of Figure 4 (P.s. – V.m.) seem incorrect. Why do they start with “ac” instead of “a”? Corrected.

Line 261: Figure 261 label for axis 2 is missing. Is there any scaling on each axis? This diagram in this form was obtained using the program PC-ORD v.6. We did not discuss the meaning of axes as we wanted to show only the divergence of ecological spaces of different types of ecotopes. Some of our thoughts are presented in the "Discussion" section when describing the dynamics of diversity in each type of ecotope.

Line 281: “ecological area”? Corrected. We suggest to use «ecological conditions».

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript deals with an interesting area of forest research, and I thank you for the hard work done by the Russian authors. However, the authors have some scope to improve the manuscript, and here are my specific suggestions:

1. In the abstract, the objectives of the study need to be clearer and more specific, rewrite the objectives of the study.
2. There is an immediate need to draw a general recommendation based on the study’s findings.
3. In Table 1, please use the footnote to describe the P.s.------. Figure 2 is not clear.
4. In Methodology, need to use sub-heading instead of paragraph (e.g., Data collection). The theoretical or analytical framework is very weak and not clearly presented.
5. Figure 2- the X-axis sub-title is missing.
6. The results of the study are very narrow and used old techniques; I don’t know how it would impact the EU.
7. The conclusion section is missing, with a future direction for the readers and a key recommendation as well.

Good luck

Author Response

We thank the reviewer for critical evaluation of the manuscript. We respond to some specific comments below.

We consider it necessary to comment here on general remarks (reviewer's remarks 2, 6 and 7). Yes, indeed, the paper is devoted to a "narrow" issue - changes in the number of species during regeneration of forest community after clearcutting. At the same time, clearcuts of different areas are still the main industrial method of timber harvesting in boreal forests not only in Russia, but also in most other countries where such activities are carried out. The transition to new ecological technologies of timber harvesting is being promoted and it should be said that Russia has a century of experience of various variants of selective logging, but there have been special articles about it, including in international journals (Ecological Processes 2019 8:39). As widely published by us and various phytosociological aspects of regeneration of vegetation on clearcuts. Strangely enough, there is not much information on the change in species diversity of vascular plants against the background of other groups of organisms (Gustafsson, L., Hannerz, M., Koivula, M. et al. Research on retention forestry in Northern Europe. Ecol Process 9, 3 (2020). https://doi.org/10.1186/s13717-019-0208-2), so we have tried to fill this gap. At the same time, we agree with the reviewer that attention should be paid to these issues, so we have expanded the "introduction" and "discussion" sections. And, of course, we are thinking of preparing special recommendations for loggers, which will include not only information on species diversity, but also methods of preserving the forest environment in general. But this cannot be part of this publication.

 1. In the abstract, the objectives of the study need to be clearer and more specific, rewrite the objectives of the study. Yes, we rewrite.

2. There is an immediate need to draw a general recommendation based on the study’s findings.

3. In Table 1, please use the footnote to describe the P.s.------. The description is added.

Figure 2 is not clear. We have made an explanation to the picture in the caption. In addition, these schemes only illustrated the succession stages and our approach and method werediscussed in detail in article (the link to which is in the text).

4. In Methodology, need to use sub-heading instead of paragraph (e.g., Data collection). The theoretical or analytical framework is very weak and not clearly presented. Corrected.

5. Figure 2- the X-axis sub-title is missing.

The x-axis shows different series of restoration of forest communities after logging, the overall gradient of these options changes as soil humidity increase (the arrow from left to right shows this increase).We've detailed the caption under the drawing.

 6. The results of the study are very narrow and used old techniques; I don’t know how it would impact the EU.

7. The conclusion section is missing, with a future direction for the readers and a key recommendation as well.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents a critical methodological fault which implies that the results/conclusions do not respond to the research aim.

To make a good comparison between forest gaps, the same situation should be compared. Old forests have forest gaps, which occur naturally, by tree fall by natural alteration agents: wind, snow, and age. This forest gap represents the first stage of secondary succession with high plant diversity. If you do not study these gaps, of course, the artificial ones (clear cut) show, ever, surely, a high plant diversity, but the comparison is not real, nor scientific soundness.

The authors do not show the number of plots studied, nor is there a statistical comparison between them. The study talks about two main variables: forest steps and forest types. A two-way ANOVA should be done to look for the main effect influence; forest stage, forest type or both.

The ecology Index diversity used is Simpson. The Simpson index is a dominance index. Another index, as Shannon should be used to obtain relevant information, not only about richness, but about equitability too. Richness and equitability are the main parameters that describe the ecological diversity of the community.

Author Response

We thank the reviewer for the critical comments that helped us to improve the article. We hope that we have correctly understood the reviewer's comments and made appropriate changes to the text. The answers to specific remarks are below.

The manuscript presents a critical methodological fault which implies that the results/conclusions do not respond to the research aim.

We have made some adjustments to both the aims of the study and the conclusions. But the largest changes we made in the "introduction" and "discussion" sections to clarify some of our positions.

To make a good comparison between forest gaps, the same situation should be compared. Old forests have forest gaps, which occur naturally, by tree fall by natural alteration agents: wind, snow, and age. This forest gap represents the first stage of secondary succession with high plant diversity. If you do not study these gaps, of course, the artificial ones (clear cut) show, ever, surely, a high plant diversity, but the comparison is not real, nor scientific soundness.

We have added a discussion on this issue to the text of the article and hope that we have clarified our position on this issue.

The authors do not show the number of plots studied, nor is there a statistical comparison between them. The study talks about two main variables: forest steps and forest types. A two-way ANOVA should be done to look for the main effect influence; forest stage, forest type or both.

Sorry, but the number of observations, both by ecotope types and succession stages were specified in the methodology section (in the data collection section). In preparing the paper, we applied various mathematical methods, presenting only those that correctly and clearly demonstrate the results.  We conducted a 2-factor ANOVA, formally it only confirmed the correctness of our methodological approach, which we wrote about according to your recommendation.

The ecology Index diversity used is Simpson. The Simpson index is a dominance index. Another index, as Shannon should be used to obtain relevant information, not only about richness, but about equitability too. Richness and equitability are the main parameters that describe the ecological diversity of the community.

Both the Simpson index and the Shannon index describe community structure, differing in details. We also calculated the Shannon index for our data, and it showed absolutely similar results to the Simpson index. Why did we choose the Simpson index? Theoretically, it is more suitable for the studied communities, emphasizing the dominants, moreover, its value varies from 0 to 1, which is easier to visualize.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Changes were made properly