Round 1

Reviewer 1 Report

The authors use remote sensing and GIS data to determine the correlation between land surface attributes and the amount of forest ingress into agriculture land in South West Russia. Although the methods appear sound the paper is not well written. In particular the discussion does not cite any existing literature to build the case for the conclusions. The authors suggest that the amount of moisture and lack of agriculture (cropland farming and ranching) are most likely the dominant factors controlling the amount forest ingress. Based on other literature and correlations they present here – I agree that this is a strong hypothesis; however, I don’t see a compelling case for any factors that “influence” the density of forests. This type of analysis needs to use a weight of evidence approach to build a strong case for this conclusion. One suggestion could be to state hypotheses and then develop the results, and proper discussion to support or refute the hypotheses.

 

The paper is poorly organized and the writing needs to be improved. A few specific comments below. However, I did not do a complete editorial review because of the larger shortcomings of the paper.

L100 have been ploughed up – were cultivated. Or ....almost all of the forests have been converted to agriculture land.

Section 2.2 seems out of place. The objectives are at the ends of the study with the “aim” This section should be removed and incorporated into the introduction. “Study area” should be the first section of the methods.

Section 3.1.2. Data on tree density in light forests and 3.1.2. Data on the relief parameters of the study area are hard to read. Please use a paragraph format similar to 3.2.1.

There is no need for all the sub headings in methods. I would suggest just Materials and Methods and then one layer of sub headings right now there are more methods in source material than “source material”.

Tenses in the methods sections are mixed, use all past or future tense.

Include citations for the spearman coefficient and the Shapiro-Wilk test used to determine that the distribution was not normal.

Author Response

AUTHORS’ RESPONSE TO REVIEW COMMENTS

Journal:                     Geosciences

Manuscript №:      931503

Title of Paper:              The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe

Authors:           Pavel Ukrainskiy, Edgar Terekhin, Artyom Gusarov, Eugenia Zelenskaya and Fedor Lisetskii

Date Sent:       29 August 2020

 

We sincerely appreciate the time and effort put in by the Editor and the reviewer to review our manuscript. All issues raised as indicated in the review report have been addressed. Inserted corrections are blue-highlighted highlighted in revised version. We do believe that the revised version of our manuscript can meet the publication requirements of the journal.

We look forward to having a favourable response.

 

Comment 1

The authors use remote sensing and GIS data to determine the correlation between land surface attributes and the amount of forest ingress into agriculture land in South West Russia. Although the methods appear sound the paper is not well written. In particular the discussion does not cite any existing literature to build the case for the conclusions. The authors suggest that the amount of moisture and lack of agriculture (cropland farming and ranching) are most likely the dominant factors controlling the amount forest ingress. Based on other literature and correlations they present here – I agree that this is a strong hypothesis; however, I don’t see a compelling case for any factors that “influence” the density of forests. This type of analysis needs to use a weight of evidence approach to build a strong case for this conclusion. One suggestion could be to state hypotheses and then develop the results, and proper discussion to support or refute the hypotheses.

 

The revised version of the text provides citations and facts when discussing the results. Arable land has not been studied in the work. The objects of study were only pastures and hayfields located in the small dry valleys network. Abandoned arable land is very rare in the study area.

Comment 2.

L100 have been ploughed up – were cultivated. Or ....almost all of the forests have been converted to agriculture land.

For clarity, the sentence has been split into two separate sentences. Almost all the steppes have been turned into arable land. Two thirds of the forests were cut down and then turned into arable land. In the revised version: «By now, almost all the steppes that were widespread there in the 17th century have been ploughed up. In addition, by now, two-thirds of the forests that grew there in the 17th century have been cut down and then also ploughed up [34]».

Comment 3.

Section 2.2 seems out of place. The objectives are at the ends of the study with the “aim” This section should be removed and incorporated into the introduction. “Study area” should be the first section of the methods.

 

We have merged Section 2.2 with Section 2.1. The Study area has been moved to «Materials and Methods» as the first section.

Comment 4.

Section 3.1.2. Data on tree density in light forests and 3.1.2. Data on the relief parameters of the study area are hard to read. Please use a paragraph format similar to 3.2.1.

The Section 3.1.2 was indeed relatively large and lengthy. We've made edits to improve the readability of the text, and have significantly re-formatted these paragraphs, making them a table.

Comment 5.

There is no need for all the sub headings in methods. I would suggest just Materials and Methods and then one layer of sub headings right now there are more methods in source material than “source material”.

The number of subheadings has been reduced. In the revised version of the manuscript, there is only one subheading layer.

Comment 6.

Tenses in the methods sections are mixed, use all past or future tense.

In the revised version of the manuscript, in the section on methods, one verb tense (The past tense) has been used.

Comment 7.

Include citations for the spearman coefficient and the Shapiro-Wilk test used to determine that the distribution was not normal.

The revised manuscript includes references to the work of Shapiro and Wilk, as well as Spearman.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments to Author

Manuscript Number: geosciences-931503

Title: The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe: A case study of the Belgorod Region, SW European Russia

 

General comment

This study evaluated spatial variation in the density of trees in the forest steppe zone in the Belgorod Region of Russia and analyzed its correlations with topographic relief.

Understanding the relationship between geographical factors and tree density in the East European Plain is important for assessing the impacts of climate change on vegetation. This study shows differences in trends between local and regional scales and, as a major trend, points out that differences in moisture conditions affect stem density. Data analysis using GIS seems to be appropriate, and valuable results have been obtained.

  I suggest publication of this paper after some revisions from the authors. I have made the following suggestions for improvement.

 

1. This research focuses only on tree density, with no discussion of differences in tree species, age, or growth parameters such as tree height. For example, for different tree species, density may be different even if the topography and position are the same. Please describe tree species and their relationships with spatial change.

 

2. Some topographic factors were used to describe relief, but the influences of other climate factors, such as precipitation, temperature and snow, and of geological factors, such as soil characteristics and soil types, should be addressed. Climate may vary spatially within this region. The trend in annual precipitation is noted, but it is likely that there are spatial variations due to topography and altitude. The results would be further improved if an analysis based on this high-resolution information was performed.

 

3. In my opinion, it is necessary to describe the spatial variation in the characteristics of climate, soil, and tree species distribution of the study area. In addition to tree density due to climate change, changes in tree species comprise important information.

 

4. Please describe in more detail how stem density is measured. Is it possible to count the number of all trees from satellite images? Do you actually go to all plots and measure?

 

5. Why are most reliefs not significant at the local scale? Analysis on a more detailed scale should show notable tendencies. The local scale results suggest that tree density varies considerably. It is necessary to consider, for example, analysis by tree species.

Author Response

AUTHORS’ RESPONSE TO REVIEW COMMENTS

Journal:                     Geosciences

Manuscript №:      931503

Title of Paper:              The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe

Authors:           Pavel Ukrainskiy, Edgar Terekhin, Artyom Gusarov, Eugenia Zelenskaya and Fedor Lisetskii

Date Sent:       29 August 2020

 

We sincerely appreciate the time and effort put in by the Editor and the reviewer to review our manuscript. All issues raised as indicated in the review report have been addressed. Inserted corrections are blue-highlighted highlighted in revised version. We do believe that the revised version of our manuscript can meet the publication requirements of the journal.

We look forward to having a favourable response.

 

Comment 1

This research focuses only on tree density, with no discussion of differences in tree species, age, or growth parameters such as tree height. For example, for different tree species, density may be different even if the topography and position are the same. Please describe tree species and their relationships with spatial change.

The species composition of light forests is uniform. It consists mainly of wild fruit trees and shrubs - apple, pear, hawthorn, rose hips. These species grow in open spaces without the formation of closed thickets. The differences are associated with the introduction of forest species that penetrate from nearby indigenous forests and artificial windbreaks. Primarily, these are alien species from the windbreaks - white acacia and ash-leaf maple. In addition to alien species, native species are introduced from the forests. Usually these are species of the genus elm, maple, ash, and rarely oak.

We do not have detailed data on the species composition of trees at each plot. For the territory of the Belgorod Region and neighboring regions of Russia, such detailed studies have not yet been carried out by anyone. But we can say that the presence of forest species increases the density of trees in open woodlands. The influence of forest species can be estimated indirectly. To do this, we calculated the correlation of the density of trees in light forests with the distance from the nearest windbreak or indigenous forest (the closest source of introduction of forest species), the area of the nearest forest, and the density of windbreaks in the vicinity of each plot. At the local level (raw data, without smoothing interpolation, i.e. σ = 0) there is a significant correlation with the distance from potential sources of introduction of forest species (distance to the nearest indigenous forest or  windbreak) - Spearman's ρ = -0.18 at p = 0.01. Also, the density of trees correlates with the area of the nearest indigenous forest (for σ = 0 Spearman's ρ = 0.21 at p = 0.003). When moving from the local level to the subregional level, there is a significant correlation with the density of windbreaks in the vicinity of each plot. The maximum correlation is observed when smoothing with σ = 10 km - Spearman's ρ = 0.20 at p = 0.004. We have added all these results to the revised version of the manuscript.

 

Comment 2

Some topographic factors were used to describe relief, but the influences of other climate factors, such as precipitation, temperature and snow, and of geological factors, such as soil characteristics and soil types, should be addressed. Climate may vary spatially within this region. The trend in annual precipitation is noted, but it is likely that there are spatial variations due to topography and altitude. The results would be further improved if an analysis based on this high-resolution information was performed.

 

Climate variability within the Belgorod Region is weak. There is a change in precipitation and temperature in the direction from northwest to southeast. In the Belgorod Region, there are no noticeable changes in temperature and precipitation that would be associated with the relief. There are no conditions for such changes in the region, because the height difference is too small. If for the entire region the height difference is 200 m, then the local height difference is usually 30-50 m.

To assess the influence of climate on the density of trees in light forests of the Belgorod Region, we estimated the correlation between the density of trees and the hydrothermal coefficient. The hydrothermal coefficient is statistically significantly correlated with tree density (at the local level Spearman’s ρ = -0.23 при p=0,001, at the subregional level Spearman’s ρ = -0.36 при p=1,17·10-7, at the regional level Spearman’s ρ = -0.89 by p<2.2·10-16). But we have feedback. And this is biologically meaningless. That is, we have a correlation, but we do not have a causation. These patterns require a separate study. In this case, the hydrothermal coefficient correlates with the absolute height (Spearman’s correlation coefficient ρ = 0.60 by p<2.2·10-16). We talked about this in line 350-356. In the revised version of the manuscript, we have provided quantitative data in favor of this argument.

 

Comment 3

In my opinion, it is necessary to describe the spatial variation in the characteristics of climate, soil, and tree species distribution of the study area. In addition to tree density due to climate change, changes in tree species comprise important information.

 

Temperature change in space is described in lines 96-97. The change in precipitation in space is described in lines 99-100. For the territory of the Belgorod Region, it is impossible to give a more detailed description of the spatial variation of climatic indicators. First, because this variation is really weak. Secondly, because there are no climatic data with high detail (only 6 meteorological stations operate on the territory of the Belgorod Region).

Due to the relatively small area of the territory, the species composition of forests in the Belgorod Region is also homogeneous. On line 107, we indicate that there are mainly oak forests in the area. In the revised version of the manuscript, in the description of the study area, we listed other types of trees that grow in the oak forests along with oak.

The soil cover within the region varies slightly. Mainly the chernozem soil type is widespread. Among the chernozems, there are inclusions of soils of another genetic type - gray forest soils. The plots for which the number of trees was estimated are located within chernozem soils.

 

Comment 4

Please describe in more detail how stem density is measured. Is it possible to count the number of all trees from satellite images? Do you actually go to all plots and measure?

 

The process of vectorizing stand-alone trees is described in lines 151-154. The raw data used are described in lines 131-134.

The number of trees was calculated only from satellite images. With this method, the youngest trees (up to 3-5 years old) remain unaccounted for. These trees have too small a crown to be detected by satellite imagery.

But underestimation of young trees is not a problem. If we were doing a ground survey, we would have to remove young trees from the mapping results. We just wanted to show the density of trees as a cumulative result of the development of light forests over the past two to three decades. Young trees would greatly distort the results, because the young trees are very unstable. The number of new seedlings varies greatly from year to year. At the same time, the vast majority of young trees die. This is due to insufficient moisture, burning grass by humans, and grazing.

 

Comment 5

Why are most reliefs not significant at the local scale? Analysis on a more detailed scale should show notable tendencies. The local scale results suggest that tree density varies considerably. It is necessary to consider, for example, analysis by tree species.

 

We assume that not only fixed effects (fixed effects) affect the density of trees in light forests. Random effects have a big impact. We are not aware of random effects. We cannot account for the impact of these effects.

Random effects are strongest at the local scale. The transition from a local scale to a subregional and regional scale is performed using smoothing interpolation of the initial data on the density of trees (local level data). As we increase the search radius in smoothing interpolation, we increase the generalization of the results. By generalization, random effects are removed.

Also, most of the characteristics of the relief are not significant on a local scale, since other factors are more influenced at the local scale. We believe that at the local level, the position of the sources of the introduction of forest species is more strongly influenced. There is also the influence of human activities. We indicated this in line 365-373.

Author Response File: Author Response.docx

Reviewer 3 Report

The study “The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe: A case study of the Belgorod Region, SW European Russia” presents a correlation analysis between orographic variables and tree density in recently colonized herbaceous ecosystems.

My main concern with this study is the lack of precision when describing the data and methods used, and the lack of quantitative results presented.

There are some grammar issues here and there, so I recommend you to ask for a professional English editing.

 

Specific comments:

The tittle is way too long. It describes the study area in too much detail. Try to substantially reduce it. With maximum one & half or two lines you should fit it.

 

Abstract: It presents the study but it clearly needs to be polished and be improved to be much more concise.

L.15-16: It’s not clear who is invading what. I guess it should be “an invasive process by tree vegetation … of steppe valleys.

L.16: 4 adjectives describe the valleys, be concise in the abstract.

L.17: how many decades?

L.19: patterns instead of parameters?   

L.21: Do not use abbreviations in the abstract. The reader does not know what these stand for.

L.22: Which others?

L.24: To which network do you refer to?

L.26: greater than what?

 

Introduction: It is presented the phenomenon under study, the invasion of herbaceous ecosystems by wood vegetation, and the aim of the study, that is, determine whether relief influence its dynamics. The Introduction is short and concise and

L.38: Do not exactly repeat L.33

L.40: “and” missing

L.42: I still do not know what this “network” refers to. It is a network of valleys? Why do you call it small-dry-valley?

L.46-47: It is inconsistent. They can be which 2 things?

L.58-60: Rephrase it, or split it, otherwise it is impossible to follow.

 

Study area: The description of the study area is very extensive. Some of the information is irrelevant for the purpose of the study. Merge subsections 2.1 and 2.2 and make an effort to highlight the main characteristics of the study area that can drive open-woodlands dynamics.

L.73: write 000 instead of thousand (here and elsewhere)

L.78: name for SRTM

Fig.1: on the right, make the red line wider or stronger. Use another colour for plots so these can be distinguished.

L.86: do not repeat in brackets what it’s already been said

L.96-97: It’s already been said 3 paragraphs before

L.97: Chernozem in minuscule? 

 

Methods: Methods lack of precision and many important information to verify the validity of those is missing.

L.119: So, if I understand correctly, you don’t have exact, inventoried tree density data. If the phenology of the tree species growing in the region is quite variable, or the tree ages are not even, using space images could be an issue for later visual detection of individual trees. Do you know the exact date of your images? Did you know the sensor, so the resolution, of the images you used for your study?

L.122: How confident is your visual analysis of remote sensing data? How many people carried it out? Which were the criteria to classify an area as light forest (or any other cover)? Did you consider using a supervised / unsupervised algorithm to categorize the images into land-cover types?

L.123: “of each such area” is redundant.

L.125: How these plots were distributed across the territory? That is, which criteria or decision tree did you apply to select the locations? To do so, did you used an algorithm or did you select them by expert knowledge?

L.126, 134: Use either “sites” or “plots” along the manuscript to refer to locations studied.

L.138: How did you calculate the density of trees in each of the 200 plots? Did you use an algorithm to detect trees and count them, or did you do it by hand?

L.146: Use “variables” instead of “parameters”.

L.153: I think you mean “this” instead of “these”.

L.154, 156, 157, 163: Make an effort to synthetize all the tools, software, operation, … you used to compute the orographic variables. Maybe a table indicating the variable, unit, description, values (if categorical), tool, operation done to derive it, … could be concise and exhaustive way to present all your variables.

L.211: in THE correlation analysis.

L.215-216: It has already been said. Try to avoid redundancies along the method sub-sections. You may write that all the statistical analysis were carried out in R software at the end of the section, instead of writing every 3/4 lines. Add citation of R version used.

 

Results: Quantitative results are needed to turn the manuscript in a scientific report. How much is low, medium and high tree density? How many hectares of low, medium and high density are detected at each of the 3 levels? I suggest to concentrate Results section on description of outcomes of statistical analysis and not list/name all the local places with either low or high density of trees, as this information is quite irrelevant for a broader audience.

L.229: Incomplete or meaningless sentence.

L.232-242: It is a visual description of Fig. 3A.

L.243-253: This paragraph names the places where low/high density is found, places known by the authors, but any explication about the relationship between relief variables and density is explained or discussed.

L.325: Table N?.

 

Conclusions are very extensive and mostly repeat what is present in the Result section. Make an effort to synthetize your findings and what these be useful for.

L.362-363: It is the first time you give a concrete descriptor of tree density, which has to come first than Conclusions.

The study “The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe: A case study of the Belgorod Region, SW European Russia” presents a correlation analysis between orographic variables and tree density in recently colonized herbaceous ecosystems.

My main concern with this study is the lack of precision when describing the data and methods used, and the lack of quantitative results presented.

There are some grammar issues here and there, so I recommend you to ask for a professional English editing.

 

Specific comments:

The tittle is way too long. It describes the study area in too much detail. Try to substantially reduce it. With maximum one & half or two lines you should fit it.

 

Abstract: It presents the study but it clearly needs to be polished and be improved to be much more concise.

L.15-16: It’s not clear who is invading what. I guess it should be “an invasive process by tree vegetation … of steppe valleys.

L.16: 4 adjectives describe the valleys, be concise in the abstract.

L.17: how many decades?

L.19: patterns instead of parameters?   

L.21: Do not use abbreviations in the abstract. The reader does not know what these stand for.

L.22: Which others?

L.24: To which network do you refer to?

L.26: greater than what?

 

Introduction: It is presented the phenomenon under study, the invasion of herbaceous ecosystems by wood vegetation, and the aim of the study, that is, determine whether relief influence its dynamics. The Introduction is short and concise and

L.38: Do not exactly repeat L.33

L.40: “and” missing

L.42: I still do not know what this “network” refers to. It is a network of valleys? Why do you call it small-dry-valley?

L.46-47: It is inconsistent. They can be which 2 things?

L.58-60: Rephrase it, or split it, otherwise it is impossible to follow.

 

Study area: The description of the study area is very extensive. Some of the information is irrelevant for the purpose of the study. Merge subsections 2.1 and 2.2 and make an effort to highlight the main characteristics of the study area that can drive open-woodlands dynamics.

L.73: write 000 instead of thousand (here and elsewhere)

L.78: name for SRTM

Fig.1: on the right, make the red line wider or stronger. Use another colour for plots so these can be distinguished.

L.86: do not repeat in brackets what it’s already been said

L.96-97: It’s already been said 3 paragraphs before

L.97: Chernozem in minuscule? 

 

Methods: Methods lack of precision and many important information to verify the validity of those is missing.

L.119: So, if I understand correctly, you don’t have exact, inventoried tree density data. If the phenology of the tree species growing in the region is quite variable, or the tree ages are not even, using space images could be an issue for later visual detection of individual trees. Do you know the exact date of your images? Did you know the sensor, so the resolution, of the images you used for your study?

L.122: How confident is your visual analysis of remote sensing data? How many people carried it out? Which were the criteria to classify an area as light forest (or any other cover)? Did you consider using a supervised / unsupervised algorithm to categorize the images into land-cover types?

L.123: “of each such area” is redundant.

L.125: How these plots were distributed across the territory? That is, which criteria or decision tree did you apply to select the locations? To do so, did you used an algorithm or did you select them by expert knowledge?

L.126, 134: Use either “sites” or “plots” along the manuscript to refer to locations studied.

L.138: How did you calculate the density of trees in each of the 200 plots? Did you use an algorithm to detect trees and count them, or did you do it by hand?

L.146: Use “variables” instead of “parameters”.

L.153: I think you mean “this” instead of “these”.

L.154, 156, 157, 163: Make an effort to synthetize all the tools, software, operation, … you used to compute the orographic variables. Maybe a table indicating the variable, unit, description, values (if categorical), tool, operation done to derive it, … could be concise and exhaustive way to present all your variables.

L.211: in THE correlation analysis.

L.215-216: It has already been said. Try to avoid redundancies along the method sub-sections. You may write that all the statistical analysis were carried out in R software at the end of the section, instead of writing every 3/4 lines. Add citation of R version used.

 

Results: Quantitative results are needed to turn the manuscript in a scientific report. How much is low, medium and high tree density? How many hectares of low, medium and high density are detected at each of the 3 levels? I suggest to concentrate Results section on description of outcomes of statistical analysis and not list/name all the local places with either low or high density of trees, as this information is quite irrelevant for a broader audience.

L.229: Incomplete or meaningless sentence.

L.232-242: It is a visual description of Fig. 3A.

L.243-253: This paragraph names the places where low/high density is found, places known by the authors, but any explication about the relationship between relief variables and density is explained or discussed.

L.325: Table N?.

 

Conclusions are very extensive and mostly repeat what is present in the Result section. Make an effort to synthetize your findings and what these be useful for.

L.362-363: It is the first time you give a concrete descriptor of tree density, which has to come first than Conclusions.

Author Response

AUTHORS’ RESPONSE TO REVIEW COMMENTS

Journal:                     Geosciences

Manuscript №:      931503

Title of Paper:              The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe

Authors:           Pavel Ukrainskiy, Edgar Terekhin, Artyom Gusarov, Eugenia Zelenskaya and Fedor Lisetskii

Date Sent:       29 August 2020

 

We sincerely appreciate the time and effort put in by the Editor and the reviewer to review our manuscript. All issues raised as indicated in the review report have been addressed. Inserted corrections are blue-highlighted highlighted in revised version. We do believe that the revised version of our manuscript can meet the publication requirements of the journal.

We look forward to having a favourable response.

 

ABSTRACT

Comment 1

The tittle is way too long. It describes the study area in too much detail. Try to substantially reduce it. With maximum one & half or two lines you should fit it.

The title of the manuscript has been shortened.

 

Comment 2

It’s not clear who is invading what. I guess it should be “an invasive process by tree vegetation … of steppe valleys.

The text in this part of the manuscript has been reviseded, viz:

“An active process of the invasion of woody vegetation, resulting in the formation of light forests, has been observed in predominantly steppe (herbaceous) small dry valleys of the forest-steppe uplands of the East European Plain over the past two decades.”

 

Comment 3

L.16: 4 adjectives describe the valleys, be concise in the abstract.

The definition of the term "small-dry-valleys" has been inserted into the text of the manuscript.

Small dry valley (russ. – bálka) is a dry (or with a temporary snowmelt-induced or rainfall-induced water stream) valley with soddy slopes. It has a gently concave bottom, often without a noticeable channel, the slopes are convex, smoothly turning into watersheds. The length of small dry valleys is usually from hundreds of meters to 20-30 kilometers, the depth is from several meters to tens of meters, and the width is up to hundreds of meters. The relatively small size and the absence of a permanent watercourse at the bottom of small dry valleys is one of the diagnostic features that distinguish them from typical river valleys.

 

Comment 4

L.17: how many decades?

In the last two decades

 

Comment 5

L.19: patterns instead of parameters?

A clarification has been made. The current version of the manuscript uses "relief characteristics".

Comment 6

L.21: Do not use abbreviations in the abstract. The reader does not know what these stand for.

Changes have been made.

 

Comment 7

L.22: Which others?

In the reviseded version of the manuscript,, we specify this: «The correlation between some characteristics of the relief (the height, slope, slope exposure cosine, topographic position index, morphometric protection index, terrain ruggedness index, width and depth of small dry valleys)».

 

Comment 8

L.24: To which network do you refer to?

The definition of the term "small-dry-valleys" has been inserted into the text of the manuscript (see above).

 

Comment 9

L.26: greater than what?

L.26: больше чем что?

This part of the text in the manuscripte has been reviseded, viz:

The influence of topography on subregional and regional trends in the density of trees in light forests is greater than on local trends.

 

INTRODUCTION

Comment 10

L.38: Do not exactly repeat L.33

This has been fixed.

Comment 11

L.40: “and” missing

The Text has been verified.

Comment 12

L.42: I still do not know what this “network” refers to. It is a network of valleys? Why do you call it small-dry-valley?

The definition of the term "small-dry-valleys" has been inserted into the text of the manuscript (see above).

 

Comment 13

L.46-47: It is inconsistent. They can be which 2 things?

These are two alternative ways of developing light forests. In the future, some of them will develop along the first way, others - along the second one. But we cannot yet predict in what way they will develop.

 

 

Comment 14

L.58-60: Rephrase it, or split it, otherwise it is impossible to follow.

The aim of the study is to identify the features of the influence of the relief on the spatial patterns of changes in the density of trees in light forests in the uplands of the forest-steppe of Eastern Europe. The implementation of this aim was carried out on the example of the southwestern part of European Russia, within the Belgorod Region.

STUDY AREA

Comment 15

The description of the study area is very extensive. Some of the information is irrelevant for the purpose of the study. Merge subsections 2.1 and 2.2 and make an effort to highlight the main characteristics of the study area that can drive open-woodlands dynamics.

Subsections 2.1 and 2.2 have been merged.

 

Comment 16

L.73: write 000 instead of thousand (here and elsewhere)

We have replaced "thousand" with "000" throughout the text.

 

Comment 17

L.78: name for SRTM

We have added the name (version) of SRTM data.

Comment 18

Fig.1: on the right, make the red line wider or stronger. Use another colour for plots so these can be distinguished.

The red line was made thicker. A more contrasting color was made for the plots.

 

Comment 19

L.86: do not repeat in brackets what it’s already been said

Duplication in parentheses has been removed.

Comment 20

L.96-97: It’s already been said 3 paragraphs before

These passages of text talk about different things. In the first case, about the relief. In the second case, it is said about a natural (landscape) zone.  Only the mention of the East European Plain is common there. This link is required in both cases.

 

Comment 21

L.97: Chernozem in minuscule? 

In the revised manuscript, we wrote the word chernozem in minuscule.

METHODS

Comment 22

L.119: So, if I understand correctly, you don’t have exact, inventoried tree density data. If the phenology of the tree species growing in the region is quite variable, or the tree ages are not even, using space images could be an issue for later visual detection of individual trees. Do you know the exact date of your images? Did you know the sensor, so the resolution, of the images you used for your study?

We used the data as it is included in the available online satellite imagery mosaic. Individual trees were identified using mosaics of images with ultra-high spatial resolution (more detailed 1 m / pixel). That is, the size of the crowns of individual trees was always somewhat larger than the pixel size of the mosaic images. All satellite data used were obtained during the active growing season. Due to the relatively small area of the region studied, the phenological phases differ insignificantly within its limits. Due to taking into account the listed criteria, the obtained experimental data can be considered objective.

 

Comment 23

L.122: How confident is your visual analysis of remote sensing data? How many people carried it out? Which were the criteria to classify an area as light forest (or any other cover)? Did you consider using a supervised / unsupervised algorithm to categorize the images into land-cover types?

We did not use automated recognition methods, since in practice we were convinced of their low accuracy when solving similar problems for the study area. The scope of work on visual analysis was relatively small, since the number and area of plots were limited - 200 plots, 1 ha each. All areas with forest vegetation, the crowns of which do not close together, belong to open-woodlands. That is, free standing trees are clearly visible against the background of grass.

Comment 24

L.123: “of each such area” is redundant.

This has been fixed

Comment 25

L.125: How these plots were distributed across the territory? That is, which criteria or decision tree did you apply to select the locations? To do so, did you used an algorithm or did you select them by expert knowledge?

The selection was made based on expert knowledge. In general, the location of the plots is predetermined by the structure of the small-dry-valleys network and the presence of open-woodlands in it. Open-woodlands do not have continuous distribution in the small-dry-valleys network. They are found as separate fragments. The plots are confined to these fragments.

 

Comment 26

L.126, 134: Use either “sites” or “plots” along the manuscript to refer to locations studied.

In the current version of the manuscript, the "plots" is used.

 

Comment 27

L.138: How did you calculate the density of trees in each of the 200 plots? Did you use an algorithm to detect trees and count them, or did you do it by hand?

The counting was done manually.

 

Comment 28

L.146: Use “variables” instead of “parameters”.

This has been fixed

Comment 29

L.153: I think you mean “this” instead of “these”.

This has been fixed

Comment 30

L.154, 156, 157, 163: Make an effort to synthetize all the tools, software, operation, … you used to compute the orographic variables. Maybe a table indicating the variable, unit, description, values (if categorical), tool, operation done to derive it, … could be concise and exhaustive way to present all your variables.

A table with initial data, software and data processing methods was inserted in the manuscript.

 

Comment 31

L.211: in THE correlation analysis.

The typo has been corrected.

Comment 32

L.215-216: It has already been said. Try to avoid redundancies along the method sub-sections. You may write that all the statistical analysis were carried out in R software at the end of the section, instead of writing every 3/4 lines. Add citation of R version used.

The citation to the R version in use is inserted. Instead of repeatedly mentioning R, it says that all analysis was done in R.

RESULTS

Comment 33

Results: Quantitative results are needed to turn the manuscript in a scientific report. How much is low, medium and high tree density? How many hectares of low, medium and high density are detected at each of the 3 levels? I suggest to concentrate Results section on description of outcomes of statistical analysis and not list/name all the local places with either low or high density of trees, as this information is quite irrelevant for a broader audience.

Quantitative data on tree density and its variation are presented in the revised version of the paper.

 

Comment 34

L.229: Incomplete or meaningless sentence.

The Sentence has been edited.

Comment 35

L.232-242: It is a visual description of Fig. 3A.

The description was supplemented with quantitative data.

 

Comment 36

L.243-253: This paragraph names the places where low/high density is found, places known by the authors, but any explication about the relationship between relief variables and density is explained or discussed.

The relationship between relief and density of trees in light forests is described below in the text, when discussing the results of correlation analysis.

 

Comment 37

L.325: Table N?.

Added table number.

Comment 38

Conclusions are very extensive and mostly repeat what is present in the Result section. Make an effort to synthetize your findings and what these be useful for.

By the example of the Belgorod Region, for the first time for the landscapes of the forest-steppe uplands, typical of the East European Plain, the main regularities of contemporary changes in the density of trees in light forests of the network of small dry valleys were revealed. The emergence of these light forests is the latest trend in the development of vegetation cover in the region.

The geographic features of changes in the density of trees in light forests at various scale levels of the study (generalization) are very different. At the local level, a variegated spatial spreading is observed, in which there are no obvious spatial patterns in changes in tree density. More or less noticeable patterns begin to be determined with an increase in the generalization of tree density cartograms. At the sub-regional level, there is an alternation of areas with high and low density of trees from the west to the east of the Belgorod Region. The areas of increased density mainly cover the middle and lower parts of the basins of large rivers there, while the areas of low density of trees in light forests at the sub-regional level are confined to the interfluves of the largest rivers of the region, as well as to the upper parts of their basins. The region-wide (that is, the most generalized) trend is a consistent increase in the density of trees in the small-dry-valleys network from the northwest to the southeast of this administrative region of SW European Russia.

Relief characteristics also affect the density of trees in light forests growing in the small-dry-valleys network. Their influence is manifested through the differentiation of the moisture conditions in the territory studied, and the creation of various conditions for the fixing of tree seedlings in the soil. At the local level, the relief influence is minimal, and the density of trees is largely due to other factors. Of all the relief characteristics at the local level, statistically significant correlation is found only for the slope and TRI. In general, at the sub-regional and regional levels of generalization, the closest correlation is observed with the absolute height of the area. The second most important factor at the sub-regional level is the Morphometric Protection Index, and at the regional level, it is the depth of small dry valleys.

The expansion of light forests area into the small-dry-valleys network, which was observed in the country in the recent decades, is a very common phenomenon under modern changes in climate and land use/cover. This fact should be taken into account when planning the further economic use of the small-dry-valleys network as an inalienable element of the forest-steppe landscapes of the East European Plain, while protecting its ecosystems, as well as for the development of recreational activities and ecological (environmental) tourism.

 

 

Comment 39

L.362-363: It is the first time you give a concrete descriptor of tree density, which has to come first than Conclusions.

In the revised version, statistics on the variation in tree density are given in the results.

 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Dear authors,

 

I really appreciate the effort you have made to improve the manuscript. I would finally suggest if you could add into the text the information contained in the answers you have provided for comments 22, 23, 25, and 27, as these offer relevant information on the methodology you applied.

 

Thanks.

Author Response

AUTHORS’ RESPONSE TO REVIEW COMMENTS

Journal:                     Geosciences

Manuscript №:      931503

Title of Paper:              The influence of relief on the density of open-woodland trees within the small-dry-valley network of uplands in the forest-steppe zone of Eastern Europe

Authors:           Pavel Ukrainskiy, Edgar Terekhin, Artyom Gusarov, Eugenia Zelenskaya and Fedor Lisetskii

Date Sent:       29 August 2020

Reviewer comment.

I really appreciate the effort you have made to improve the manuscript. I would finally suggest if you could add into the text the information contained in the answers you have provided for comments 22, 23, 25, and 27, as these offer relevant information on the methodology you applied.

 

Authors' response.

We sincerely appreciate the time and effort put in by the Editor and the reviewer to review our manuscript. We have done all the suggested insertions of additional information. Inserted text fragments are highlighted in green. We do believe that the revised version of our manuscript can meet the publication requirements of the journal.

We look forward to having a favourable response.

 

Author Response File: Author Response.docx