Spatiotemporal Dynamics of Betula pendula Crown Cover on Abandoned Arable Land in a Broad-Leaved Forest Zone of Bashkir Cis-Ural
, Pavel Shirokikh *, Svetlana Zhigunova, Elvira Baisheva and Vasiliy Martynenko
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper presents a study on the spatiotemporal dynamics of crown cover of Betula pendula on abandoned arable lands in the broad-leaved forest zone of the Bashkir Cis-Ural. The authors analyze the influence of factors such as wind direction, tree height, and grazing on the distribution of birch trees and crown cover. The study uses regression models and satellite images to assess the crown cover and age of the tree stand. The use of regression models and satellite images provides a quantitative analysis of crown cover dynamics, allowing for a better understanding of the spatial patterns of tree growth. Other questions are shown below:
1. The paper lacks a clear explanation of the methodology used for the regression models and the analysis of satellite images. More details on the statistical methods and data processing would enhance the reproducibility of the study.
2. There is less discussion on the implications of the findings and their relationship to forest management and conservation practices.
3. Other aspects could be illustrated using diagrams or plots with a comprehensive presentation of the results.
4. Some forest vertical structures, diverse species compositions and natural environmental efficacy could be elaborated with varying situations or ecosystem factors delivering. A paper elucidating environmental light effecting on forest plots could be mentioned as follows: “Shortwave Radiation Calculation for Forest Plots Using Airborne LiDAR Data and Computer Graphics”.
Overall, the paper presents a valuable study on the spatiotemporal dynamics of crown cover of Betula pendula on abandoned arable lands. The use of regression models and satellite images provides insightful findings on the factors influencing the distribution of birch trees. However, some improvements are needed in terms of methodology clarity.
Author Response
Dear Reviewer. We are thank you for careful review of our article. Your recommendations and comments are very useful and improved the quality of manuscript. Below are the answers to your comments (in the text of article corrections are marked in green color).
- The paper lacks a clear explanation of the methodology used for the regression models and the analysis of satellite images. More details on the statistical methods and data processing would enhance the reproducibility of the study.
Answer: We agree with your opinion. We have significantly revised the “Materials and Methods” section, adding more detail to explain the methodology used to build the regression models and the analysis of satellite images. (L. 149-165, 180-192).
- There is less discussion on the implications of the findings and their relationship to forest management and conservation practices.
Answer: Thanks for comment. These aspects have been further discussed in the “Discussion” section. (L. 357-374).
- Other aspects could be illustrated using diagrams or plots with a comprehensive presentation of the results.
Answer: We added a graph of the regression model of the dependence of crown cover on the red channel values in the “Materials and Methods” section, as well as illustrations of wind rose diagram during the period of main seed dispersal in the study area in the “Discussion” section. (figures 3, 8).
- Some forest vertical structures, diverse species compositions and natural environmental efficacy could be elaborated with varying situations or ecosystem factors delivering. A paper elucidating environmental light effecting on forest plots could be mentioned as follows: “Shortwave Radiation Calculation for Forest Plots Using Airborne LiDAR Data and Computer Graphics”.
We read the recommended article with interest. Unlike the forests discussed in this article, our birch forests are monodominant, and their vertical structure is not expressed. However, there are factors that we also considered in the manuscript, namely the spatial and temporal heterogeneity of light fluxes. In this regard, we noted in the "Methodology" section that our regression model is applicable to as close as possible the dates of the retrospective images used. Also, by the end of winter, the share of the red spectrum in the total light flux changes. It was discussed earlier in another article cited in this manuscript (Fedorov et al., 2022).
Overall, the paper presents a valuable study on the spatiotemporal dynamics of crown cover of Betula pendula on abandoned arable lands. The use of regression models and satellite images provides insightful findings on the factors influencing the distribution of birch trees. However, some improvements are needed in terms of methodology clarity.
Thank you again for your favorable review and valuable recommendations.
Nikolai Fedorov
Ufa Institute of biology - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences
Prospect Octyabrya, 69, Ufa 450054, Russia
fedorov@anrb.ru
December 06, 2023
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors1.In abstract. The author used early spring images from Landsat 5-8 and Sentinel-2 satellites to assess the contemporary and retrospective values of crown cover. But we did't find the detail how authors used a regression model to assess the contemporary and retrospective values of crown cover.
2. In introduction. The research progress and existing problems should be introduced. What are the scientific issues that need to be addressed?
3. In materials and methods. The basic information and preprocessing of remote sensing images should be not introduced. The size of the sample plot is 30m × 30 m, which is matched with the Landsat image pixel, but the Sentinel-2 pixel has 10 m, 20 m, and 60 m, so how does the author solve the pixel matching problem?
4. In discussion. The discussion was relatively simple, and the results should be compared with the others, reflecting the research highlights of the article, or the existing problems and how to improve.
5. In conclusion, the literature is generally no longer cited to reflect the originality of the article.
Comments on the Quality of English LanguageThe English language is of average quality and requires extensive editing of the English language
Author Response
Dear Reviewer. We are thank you for careful review of our article. Your recommendations and comments are very useful and improved the quality of manuscript. Below are the answers to your comments (in the text of article corrections are marked in blue color).
- In abstract. The author used early spring images from Landsat 5-8 and Sentinel-2 satellites to assess the contemporary and retrospective values of crown cover. But we did't find the detail how authors used a regression model to assess the contemporary and retrospective values of crown cover.
Answer: We agree with your opinion. We have significantly revised the “Materials and Methods” section, adding a more detailed explanations of the methodology used to build the regression models for assessing modern and retrospective values of crown cover (L. 149-165, 180-192, corrections are marked in green color).
- In introduction. The research progress and existing problems should be introduced. What are the scientific issues that need to be addressed?
Answer: Thanks for your valuable comments. In the “Introduction” section, we added data on the use of LiDAR to identify the dynamics of forest cover of abandoned agricultural lands and global Tree Canopy Cover change. Also, we have more clearly defined the scientific problems to be solved. (L. 81-83, 87-94).
- In materials and methods. The basic information and preprocessing of remote sensing images should be not introduced. The size of the sample plot is 30m × 30 m, which is matched with the Landsat image pixel, but the Sentinel-2 pixel has 10 m, 20 m, and 60 m, so how does the author solve the pixel matching problem?
Answer: The calculation was performed using the Zonal Statistics module in QGIS. If the several image pixels fall into one polygon (grid cell), the average value of the red channel is calculated. For 10-metre Sentinel-2 pixels, the average brightness value of all pixels falling inside the polygon is calculated.
- In discussion. The discussion was relatively simple, and the results should be compared with the others, reflecting the research highlights of the article, or the existing problems and how to improve.
Answer: “Discussion” section has been expanded by the possible practical applications of the research results, and the limitations of this method have been discussed. (L. 357-374).
- In conclusion, the literature is generally no longer cited to reflect the originality of the article.
Answer: We have revised the “Conclusion” section, focusing on our results and the prospects for further research. (L. 381-392).
The English language is of average quality and requires extensive editing of the English language.
Answer: We have corrected English language of the manuscript, but if the quality is still not good enough, we would like to use MDPI editing services.
Nikolai Fedorov
Ufa Institute of biology - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences
Prospect Octyabrya, 69, Ufa 450054, Russia
fedorov@anrb.ru
December 06, 2023
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript is well-constructed and written. It can be accepted for publication after a minor revision.
L45-47: Does illumination refer to light illumination? Would the term ‘light availability’ mentioned [Reference: 8] be more appropriate?
Introduction section: The authors must add some lines on methodologies (data and methods) adopted by past studies for such assessment, including crown cover and their linkages with tree age. In addition, examples of LIDAR data usage for such studies.
It is unclear whether the authors collected ground data on CC or not. Did the authors use LIDAR data for CC estimation?
R=-90 and R2=81.39? Shall it be -0.9 and 0.8139?
Table 2: What are the distances considered as near and far from the seed source?
Did the authors refer to TCC% data by Hansen et al. (2013)?
There is a scope for improving the discussion section.
Is there a possibility of scaling up such analysis at a large scale using satellite remote sensing data?
Author Response
Dear Reviewer. We are thank you for careful review of our article. Your recommendations and comments are very useful and improved the quality of manuscript. Below are the answers to your comments (in the text of article corrections are marked in red color).
L45-47: Does illumination refer to light illumination? Would the term ‘light availability’ mentioned [Reference: 8] be more appropriate?
Answer: We agree with your opinion. Done. (L. 46-47).
Introduction section: The authors must add some lines on methodologies (data and methods) adopted by past studies for such assessment, including crown cover and their linkages with tree age. In addition, examples of LIDAR data usage for such studies.
Answer: Thanks for comments. We added to the “Introduction” section the data on the use of LiDAR to identify the forest cover dynamics on abandoned agricultural lands. (L. 80-83).
It is unclear whether the authors collected ground data on CC or not. Did the authors use LIDAR data for CC estimation?
Answer: During the period of full crown development (in the study area - July), 189 sample plots sized 30 × 30 m were laid. On each sample plot, stand composition, crown density and height were recorded using field research and LiDAR data. We have significantly revised the “Materials and Methods" section, adding more detail to explain the methodology. (L. 149-165, 180-192).
R=-90 and R2=81.39? Shall it be -0.9 and 0.8139?
Answer: Thanks for comments. Done. (L. 173-174).
Table 2: What are the distances considered as near and far from the seed source?
Answer: The distance from the seed source to the opposite edge of the sample plots (the part of the sample plot furthest away from the seed source) ranged from 391 to 776 m, and to the area as close as possible to the seed source – up to 50 m away depending on the different sample plots.
Did the authors refer to TCC% data by Hansen et al. (2013)?
Answer: We referred to the papers of Hansen et al. (2013, 2022). (L. 87-90), whose cartographic data on overgrowth of agricultural land included our sample plots in the study area. There is no doubt that the map of Hansen and his co-authors is a global product to estimate forest growth and loss over large areas, but it has some limitations, namely that only two time periods (2000 to 2012 and 2012 to 2022) have been considered. For our purposes, it was necessary to conduct a more detailed study of birch colonization on abandoned arable land.
There is a scope for improving the discussion section.
Answer: “Discussion” section has been expanded by the possible practical applications of the research results, and the limitations of this method have been discussed. (L. 357-374).
Is there a possibility of scaling up such analysis at a large scale using satellite remote sensing data?
Answer: Yes, such a possibility exists. We used remote sensing data (red channels of Landsat and Sentinel-2 satellite images). The methodology used for retrospective analysis of birch overgrowth on abandoned farmland may be used to analyze the formation of the spatial structure of the stands formed by other tree species with different seed dispersal and seed productivity. The only limitation of this study is the heterogeneous stand composition included the coniferous, which in the winter practically do not change their projective cover compared to deciduous trees.
Nikolai Fedorov
Ufa Institute of biology - Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences
Prospect Octyabrya, 69, Ufa 450054, Russia
fedorov@anrb.ru
December 06, 2023
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsAfter thorough scrutiny of the manuscript, substantial improvements have been made for the whole manuscript, with details melioration, e.g., diagram quality betterment, result analysis enrichment, clearer information conveyance and comprehensive methodology presentation. Hence, I made the decision to accept the current form.
