What Are Contemporary Mexican Conifers Telling Us? A Perspective Offered from Tree Rings Linked to Climate and the NDVI along a Spatial Gradient

Round 1

Reviewer 1 Report

I congratulate the working group for the research carried out, which is very interesting. The objective of the paper is to demonstrate whether there is a correlation between the chronological data of collection of young tree growth in the pine family and Minimum Temperature, Maximum Temperature, monthly precipitation and altitude. 

In Addition, the greenness level of conifers is considered by studying NDVI as a function of altitude.

The dataset covers 12 species of Pines located in 20 different sites in the state of Mexico, referring to the period 1985-2019.

The methodology applied in analyzing the relationship among the different indices, also taking advantage of R packages, turns out to be in accordance with the current literature.

My comments are as follows.

line 166: I recommend adding an image of the core drilling in the field,

line 167: I recommend adding an image of the Velmex ultra precision and bring back a table with the data sheet

line 197: replace the number 12 with letters, as done in line 189

line 2017: " Dunn test" insert citation

line 274: you should define the abbreviation "RWI," since this one never appears in the text

line 273-277: put the name of the package used to print the graph

linea 305-308: put the name of the package used for graph creation

line 318-319: put the name of the package used for graph creation

line 335-340: put the name of the package used for graph creation

lines 371-377: the verb to seem is repeated too many times, change it into a synonym

lines 493-494: you should not repeat the same verb to explain in the same sentence, change it with a synonym

lines 500 - 501: you should not repeat the same verb to complement in the same sentence;

that’s all.

Author Response

Reviewer 1:

I congratulate the working group for the research carried out, which is very interesting. The objective of the paper is to demonstrate whether there is a correlation between the chronological data of collection of young tree growth in the pine family and Minimum Temperature, Maximum Temperature, monthly precipitation and altitude.

In Addition, the greenness level of conifers is considered by studying NDVI as a function of altitude.  The dataset covers 12 species of Pines located in 20 different sites in the state of Mexico, referring to the period 1985-2019.

 The methodology applied in analyzing the relationship among the different indices, also taking advantage of R packages, turns out to be in accordance with the current literature.

Thank you for your positive comments.

My comments are as follows.

line 166: I recommend adding an image of the core drilling in the field,

Done. See Figure 2.

line 167: I recommend adding an image of the Velmex ultra precision and bring back a table with the data sheet

Done. See Figure 2.

line 197: replace the number 12 with letters, as done in line 189

Done in this example and throughout the manuscript for consistency. See line 175.

line 217: " Dunn test" insert citation

Done. See line 229 and line 702.

line 274: you should define the abbreviation "RWI," since this one never appears in the text

Done. See line 292

line 273-277: put the name of the package used to print the graph

For this graph, we used Sigma plot software and excel.

linea 305-308: put the name of the package used for graph creation

We used Sigma plot software

line 318-319: put the name of the package used for graph creation

This graph was prepared using the ggplot2 package (Wickham 2016)

Wickham, H. (2016). ggplot2: Elegant graphics for data analysis. Springer-Verlag New York. https://doi.org/978-0-387-98141-3

line 335-340: put the name of the package used for graph creation

This graph was prepared using the ggplot2 package (Wickham 2016)

Wickham, H. (2016). ggplot2: Elegant graphics for data analysis. Springer-Verlag New York. https://doi.org/978-0-387-98141-3

lines 371-377: the verb to seem is repeated too many times, change it into a synonym

Done. See lines 387-394.

lines 493-494: you should not repeat the same verb to explain in the same sentence, change it with a synonym

Done. See lines 507-509.

lines 500 - 501: you should not repeat the same verb to complement in the same sentence;

Done. See lines 525-527.

 that’s all.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

The manuscript with the title “What are contemporary Mexican conifers telling us? A perspective offered from tree-rings linked to climate and the NDVI  along a spatial gradient” aimed to understand the elevational trends in the climate response of a network of TRI chronologies of young Mexican conifers; to study the BAI index as an indicator of forest productivity and the spatial relationship between chronologies and NDVI.

This manuscript is well organized. However, there are a few comments and suggestions about this article that should be addressed:

Abstract:

Lines 28 to 29: Scientific names of the tree species should be written in italic e.g. “

 Abies religiosa”.

Line 35: I would suggest switching “used” to “utilized”.

I would suggest including the word dendroecology or dendrochronology in your abstract. It can be difficult for the readers to understand, although it is implied in the text. For instance, the authors can adapt the line 18.

Introduction:

Lines 69 to 75: I would suggest including more studies about the use of the NDVI or other indices in this context. No more than 75 words.

Line 85: I would suggest to exclude “For this reason” because is a new paragraph.

The introduction is supposed to terminate with a “schema” of the rest of the paper. I would suggest adding a small text with the following sections.

Materials and Methods:

Lines 100: I would suggest to put the figure 1 in the first place and the table 1 after the text about dendrochronological statistics.

Line 111 to 152: The description of the different species is a bit confused. I would considering to put this information on a nice table with the following parameters: Specie; Soils Type; Rock;Altitude…  

Line 114: “thin soils” or “shallow soils”?

Line 118: What is the commum use of the species? I would suggest to include the commum use of the species.

Line 124: “thin” or “shallow”?

Line 166: PVA glue is a Polyvinyl acetate? I would suggest writing in full.

Line 170: Add manufacturer information (example: Velmex, New York, United States of America). Other example in R (Version 4.3.3, ….). Consider adding this information to the rest of the document.

Line 197: I would suggest adding the bibliographic reference about the BAI. I recommend wrtting “(Equation 1)”. Consider to the rest of the document.

Line 218: I would suggest adding the bibliographic reference about the NDVI.

Line 219: I recommend changing R to RED.

Line 223: “lm” is Linear Model, wright?

General comment: The authors described all the methods used.

Results:

General comment: the authors described that they observed.

Discussions:

Line 476: I recommend changing the sentence for: “The advent of tech-475 nologies such as GEE [29] and the use of unmanned aircraft (UAVs) offer promising perspectives [64].

Line 478: “To our knowledge” or “To the best of our knowledge”?

General comment: The authors discuss the results obtained in this section and put the results in perspective with other similar papers. The authors explained the significance of results and how they contribute to advance knowledge. Limitations and outline strengths were addressed.

Conclusions:

The conclusions are consistent with the evidence and arguments presented. However, I recommend adding further research. For instance, the study of site index (SI) using: slope, aspect, soil classification (leptosoils, umbrisols, others)…

Appendix A:

The Figure A.1. was not referenced in the results section.

Author Response

Reviewer 2:

Dear authors, The manuscript with the title “What are contemporary Mexican conifers telling us? A perspective offered from tree-rings linked to climate and the NDVI along a spatial gradient” aimed to understand the elevational trends in the climate response of a network of TRI chronologies of young Mexican conifers; to study the BAI index as an indicator of forest productivity and the spatial relationship between chronologies and NDVI. This manuscript is well organized. However, there are a few comments and suggestions about this article that should be addressed:

Thank you for your positive comments.

Abstract: Lines 28 to 29: Scientific names of the tree species should be written in italic e.g. “ Abies religiosa”. Line 35: I would suggest switching “used” to “utilized”.

Done. Se lines 25-26 and line 32.

I would suggest including the word dendroecology or dendrochronology in your abstract. It can be difficult for the readers to understand, although it is implied in the text. For instance, the authors can adapt the line 18.

Done. See line 16.

Introduction: Lines 69 to 75: I would suggest including more studies about the use of the NDVI or other indices in this context. No more than 75 words.

Done. See lines 72-76.

Line 85: I would suggest to exclude “For this reason” because is a new paragraph.

Done. See line 98.

The introduction is supposed to terminate with a “schema” of the rest of the paper. I would suggest adding a small text with the following sections.

Done. We have rewritten the end of the Introduction in response to this comment. See lines 85-111.

Materials and Methods:

Lines 100: I would suggest to put the figure 1 in the first place and the table 1 after the text about dendrochronological statistics.

Done. See line 119, 154 and Appendix A.

Line 111 to 152: The description of the different species is a bit confused. I would considering to put this information on a nice table with the following parameters: Specie; Soils Type; Rock;Altitude…

We included as much of this data as possible in Table 1. See line 154.

Line 114: “thin soils” or “shallow soils”?

We now consistently use “shallow soils” throughout the text. See line 129-130 and line 152.

Line 118: What is the commum use of the species? I would suggest to include the commum use of the species.

Done. This is now explained in the Introduction section. See lines 85-90.

Line 124: “thin” or “shallow”?

See response above. See line See lines 129-130 and line 152.

Line 166: PVA glue is a Polyvinyl acetate? I would suggest writing in full.

Done. See line 185.

Line 170: Add manufacturer information (example: Velmex, New York, United States of America). Other example in R (Version 4.3.3, ….). Consider adding this information to the rest of the document.

Done. See line 190.

Line 197: I would suggest adding the bibliographic reference about the BAI. I recommend wrtting “(Equation 1)”. Consider to the rest of the document.

The reference is now included, and the equations are clearly numbered to the right of the page. See lines 216-218.

Line 218: I would suggest adding the bibliographic reference about the NDVI.

Done. See line 243 and lines 704-705.

Line 219: I recommend changing R to RED.

Done. See line 241.

Line 223: “lm” is Linear Model, wright?

Correct. See line 245.

General comment: The authors described all the methods used.

Thank you.

Results: General comment: the authors described that they observed.

Thanks.

Discussions:

Line 476: I recommend changing the sentence for: “The advent of tech-475 nologies such as GEE [29] and the use of unmanned aircraft (UAVs) offer promising perspectives [64].

Done. We have used the term “unmanned aerial vehicles (UAVs)”. See lines 499-501

Line 478: “To our knowledge” or “To the best of our knowledge”?

We have used the latter. See line 502.

General comment: The authors discuss the results obtained in this section and put the results in perspective with other similar papers. The authors explained the significance of results and how they contribute to advance knowledge. Limitations and outline strengths were addressed.

Thank you for your positive comments.

Conclusions: The conclusions are consistent with the evidence and arguments presented. However, I recommend adding further research. For instance, the study of site index (SI) using: slope, aspect, soil classification (leptosoils, umbrisols, others)… Appendix A: The Figure A.1. was not referenced in the results section.

Done. See lines 525-526.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper “What are contemporary Mexican conifers telling us? A perspective offered from tree-rings linked to climate and the NDVI along a spatial gradient” explores the relationship of tree ring and basal area increment with the NDVI, climate and elevation change. This paper has scientific sound writing and presented ground-truthing as well. It will be useful for forest studies and ecological experts. Although this paper does not involve extensive remote sensing techniques or anything new for the remote sensing community (from the remote sensing point of view) but from an ecological point of view, this is a really good paper. I have a few points for the authors

·        They have used elevation data to find the link between climate, NDVI and tree species along the spatial gradient. It is suggested to include an elevation map of a study area for a better understanding of the terrain.

·        Also NDVI map of the study area should be included in the study area.

·        To calculate NDVI they have used MODIS product. MODIS product detail about its spatial resolution (500 m) and other technical data should be included in the paper.

·        Also it would be really useful for ecologists if the authors included their ground survey pictures. Such as pictures of tree rings.

·        Line 482 - Please use subscript for CO₂    

Author Response

Reviewer 3:

This paper has scientific sound writing and presented ground-truthing as well. It will be useful for forest studies and ecological experts. Although this paper does not involve extensive remote sensing techniques or anything new for the remote sensing community (from the remote sensing point of view) but from an ecological point of view, this is a really good paper. I have a few points for the authors

Thank you for your editorial concern.

They have used elevation data to find the link between climate, NDVI and tree species along the spatial gradient. It is suggested to include an elevation map of a study area for a better understanding of the terrain.

Done. See Figure 1.

Also NDVI map of the study area should be included in the study area.

Given that NDVI values are spatial and temporal variables that are attributable to phenology, it is too complicated to depict this on a map. As a reference, we have provided mean average annual values of each of the twelve sites in Appendix C. See line 578.

To calculate NDVI they have used MODIS product. MODIS product detail about its spatial resolution (500 m) and other technical data should be included in the paper.

We did not use MODIS product, instead we obtained the NDVI values directly from GEE (see Gorelick et al, 2017). See line 236-241

Also it would be really useful for ecologists if the authors included their ground survey pictures. Such as pictures of tree rings.

Done. Figure 2.

Line 482 - Please use subscript for CO₂

Done. See line 89, line 482 and line 506.

Author Response File: Author Response.pdf

Reviewer 4 Report

This manuscript analyzed the linkage between tree-rings of contemporary Mexican conifers and the climate and the NDVI, based on 12 study sites selected along an elevational gradient from 138 to 3504 m. There is a certain meaning in this manuscript, but there are still many issues that need to be further improved and the connection between different experiments should be explained more clearly.

1.     In the Section of the Introduction, it seems abrupt to introduce the three research questions in the last paragraph. The impacts of elevation on the response of vegetation to climate are not well explained in the previous content, so it is hard to get why these questions should be further explored. Actually, there are already many manuscripts that have studied the topographical impacts on vegetation growth and productivity [1-3]. Furthermore, the relationship between the three questions should also be further explained, which also indicates the connections between the experiments. So why are these three questions?

[1] C. C. Cleveland et al., Relationships among net primary productivity, nutrients and climate in tropical rain forest: a pan-tropical analysis,” Ecology Lett., vol. 14, pp. 939–947, 2011.

[2] Xie, X., Li, A., (2021). A practical topographic correction method for improving Moderate Resolution Imaging Spectroradiometer gross primary productivity estimation over mountainous areas. International Journal of Applied Earth Observation and Geoinformation, 103, 102522.

[3] Y. Malhi, M. Silman, et. Al., Introduction: Elevation gradients in the tropics: Laboratories for ecosystem ecology and global change research ,” Global Change Biol., vol. 16, pp. 3171–3175, 2010.

2.     This manuscript concentrates on contemporary Mexican conifers, and the importance of contemporary forests is explained. However, the importance of conifers should also be addressed in the Introduction.

3.     In Section 2. Materials and Methods, all the data applied in this manuscript should be introduced firstly together in one sub-section, and then introduce the method for data processing and experiments.

4.     Section 2.5, please explain the meaning of this experiment, it seems that it is totally different from the other two experiments. It should be impossible to predict the variation of NDVI only using the elevation and latitude.

5.     Page 5, Line 187, the used climate data is at a resolution of 0.5 degrees. Whether it is too coarse to represent the climate condition in the 12 sites, since the distances between these 12 sites may be less than 0.5 degrees.

6.     Page 6 Line 211, NDVI can be used to estimate vegetation productivity [1], but it can not be a potential proxy of productivity because vegetation productivity is also highly impacted by the vegetation type and its growth environment. The authors used the MODIS NDVI product, so why not directly use the widely MODIS vegetation productivity product (MOD17 series) [2, 3]?

[1] Yuan, W., et al., 2014. Global comparison of light use efficiency models for simulating terrestrial vegetation gross primary production based on the LaThuile database. Agricultural and Forest Meteorology 192-193, 108–120.

[2] Guan Xiaobin, Chen J.M.*, Shen Huanfeng, et. al., (2021). A modified two-leaf light use efficiency model for improving the simulation of GPP using a radiation scalar. Agricultural and Forest Meteorology. 307. 2021.

[3] Running, S.W., et al., 2004. A continuous satellite-derived measure of global terrestrial primary production. Bioscience 54 (6), 547–560.

7.     Almost all the figures should be further modified to make the coordinate axis clearer. Such as in Figure 2, it would be better to change the y-axis to “correlation between RWI and PP”, the legend is also needed directly in the figure to indicate what the line the hist represents. In Figures 3-5, what is the different color in the legend represent? In Figure 1, it would also be better to add the distribution of elevation in this region since the main content is to analyze the impacts of elevation.

8.     I think the largest uncertainty of this manuscript is all the experiments are conducted only based on the 12 sites. So whether these 12 sites are representative enough to obtain all these conclusions. This issue should be well discussed.

9.     In Section 4.1, it would be better to shortly summarize the potential reasons for the different climate-growth relationships in the last paragraph.

Author Response

Reviewer 4:

This manuscript analyzed the linkage between tree-rings of contemporary Mexican conifers and the climate and the NDVI, based on 12 study sites selected along an elevational gradient from 138 to 3504 m. There is a certain meaning in this manuscript, but there are still many issues that need to be further improved and the connection between different experiments should be explained more clearly.

We are grateful for these comments and feedback. We have improved some paragraphs in the manuscript in order to better link ideas among the research questions (see lines 72-76, 101-102, 107-108).

1. In the Section of the Introduction, it seems abrupt to introduce the three research questions in the last paragraph. The impacts of elevation on the response of vegetation to climate are not well explained in the previous content, so it is hard to get why these questions should be further explored. Actually, there are already many manuscripts that have studied the topographical impacts on vegetation growth and productivity [1-3]. Furthermore, the relationship between the three questions should also be further explained, which also indicates the connections between the experiments. So why are these three questions?

[1] C. C. Cleveland et al., Relationships among net primary productivity, nutrients and climate in tropical rain forest: a pan-tropical analysis,” Ecology Lett., vol. 14, pp. 939–947, 2011.

[2] Xie, X., Li, A., (2021). A practical topographic correction method for improving Moderate Resolution Imaging Spectroradiometer gross primary productivity estimation over mountainous areas. International Journal of Applied Earth Observation and Geoinformation, 103, 102522. [3] Y. Malhi, M. Silman, et. Al., Introduction: Elevation gradients in the tropics: Laboratories for ecosystem ecology and global change research ,” Global Change Biol., vol. 16, pp. 3171–3175, 2010.

Thank you for your valuable comments and reference provided. We have rewritten this section as suggested. (see lines 91-111, 674-679).

This manuscript concentrates on contemporary Mexican conifers, and the importance of contemporary forests is explained. However, the importance of conifers should also be addressed in the Introduction.

Done (see lines 85-90).

In Section 2. Materials and Methods, all the data applied in this manuscript should be introduced firstly together in one sub-section, and then introduce the method for data processing and experiments.

We understand your point; however, we prefer to keep the characterization of the Methods section as it is in order to better describe specific experiments. Nevertheless, we have reorganized this section. See lines 118, Figure 1 and table 1.

Section 2.5, please explain the meaning of this experiment, it seems that it is totally different from the other two experiments. It should be impossible to predict the variation of NDVI only using the elevation and latitude.

Thank you for your suggestion. We have included details and strengthened the basis of the NDVI analysis, clarifying its link to forest productivity (see lines 231-234).

Page 5, Line 187, the used climate data is at a resolution of 0.5 degrees. Whether it is too coarse to represent the climate condition in the 12 sites, since the distances between these 12 sites may be less than 0.5 degrees

We understand your concern. The use of SPEI is an ideal strategy with which to address the SPEI- TRI relationships, given that is utilizes spatio-temporally accumulated droughts (from 1 to 48 months) (see  https://spei.csic.es/home.html). This evidences a close correlation between evaporative demand and its influence on the tree-ring growth. We therefore considered it appropriate to analyze the climatic response of each species through SPEI, which is widely used, and thereby strengthen the results, allowing us to disentangle the effects of climate on each species. In any case, the distance among our twelve sites is more than 0.5 degrees (see figure 1).

Page 6 Line 211, NDVI can be used to estimate vegetation productivity [1], but it can not be a potential proxy of productivity because vegetation productivity is also highly impacted by the vegetation type and its growth environment. The authors used the MODIS NDVI product, so why not directly use the widely MODIS vegetation productivity product (MOD17 series) [2, 3]?

[1] Yuan, W., et al., 2014. Global comparison of light use efficiency models for simulating terrestrial vegetation gross primary production based on the LaThuile database. Agricultural and Forest Meteorology 192-193, 108–120.

[2] Guan Xiaobin, Chen J.M.*, Shen Huanfeng, et. al., (2021). A modified two-leaf light use efficiency model for improving the simulation of GPP using a radiation scalar. Agricultural and Forest Meteorology. 307. 2021.

[3] Running, S.W., et al., 2004. A continuous satellite-derived measure of global terrestrial primary production. Bioscience 54 (6), 547–560.

Thank you for your comments and for providing these references. We agree. NDVI was assumed to represent forest productivity. However, BAI was appropriate for representing forest growth, as a potential indicator of forests productivity. We argue that BAI is suitable for this purpose, since it is an indicator of changes in incremental growth and thus forest productivity. BAI reflects changes in stem conductive area better than tree-ring width. In addition, much of the relevant literature reports BAI as a comparative measure of productivity among tree species (doi:10.3390/f8040119; https://doi.org/10.1139/cjfr-2013-0230; https://doi.org/10.1016/j.foreco.2009.04.040). However, we have reduced allusion to the concept of productivity in the manuscript as much as possible, since this variable was not evaluated per se and was not the objective of the study. Consequently, we also discarded MOD17 series as a proxy for productivity. Moreover, NDVI is commonly accepted in the relevant literature of dendrosciences as a manner by which to link forest productivity with tree-rings (see https://doi.org/10.1016/j.quascirev.2018.07.009 , https://doi.org/10.1111/geb.12802)

7. Almost all the figures should be further modified to make the coordinate axis clearer. Such as in Figure 2, it would be better to change the y-axis to “correlation between RWI and PP”, the legend is also needed directly in the figure to indicate what the line the hist represents. In Figures 3-5, what is the different color in the legend represent? In Figure 1, it would also be better to add the distribution of elevation in this region since the main content is to analyze the impacts of elevation.

Done. We have edited the figures as suggested.

I think the largest uncertainty of this manuscript is all the experiments are conducted only based on the 12 sites. So whether these 12 sites are representative enough to obtain all these conclusions. This issue should be well discussed.

Respectfully, we must partially disagree with you on this point. Our sampling strategy was based on our previous knowledge of the territory and scientifically documented experience in dendrosciences (see doi:10.3390/f8050160, https://doi.org/10.1007/978-3-030-36930-9). This allowed us to design a sampling scheme to collect representative species of the ecological regions of Mexico. To our knowledge, no previous studies have been conducted in this way. For example, in this study, we reported chronologies for the first time (e.g. , P. caribaea, etc). Nevertheless, we have in any case reconfigured the conclusions to strictly limit these to what was demonstrated with the experimental work and to recognize the limitations as you recommend. See lines 528-546.

In Section 4.1, it would be better to shortly summarize the potential reasons for the different climate-growth relationships in the last paragraph.

Done. We have summarized the idea as suggested (see lines 446-453)

Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

The authors have addressed most of my concerns, so I think it can be published after some minor revisions.

Since the remote sensing NDVI is used to represent vegetation productivity. The impacts of data noise in the AVHRR and MODIS data time series may impact the analysis. So this issue should be included in the Section of Discussion, some references maybe help:

[1] Chen, J.M., Deng, F., Chen, M., 2006. Locally adjusted cubic-spline capping for reconstructing seasonal trajectories of a satellite-derived surface parameter. IEEE Trans. Geosci. Remote Sens. 44, 2230–2237

[2] Chu Dong, Shen Huanfeng, et. al., Long time-series NDVI reconstruction in cloud-prone regions via spatio-temporal tensor completion. Remote Sensing of Environment. 264. 2021.

[3] Chen, J., Jonsson, ¨ P., Tamura, M., Gu, Z., Matsushita, B., Eklundh, L., 2004. A simple method for reconstructing a high-quality NDVI time-series data set based on the Savitzky-Golay filter. Remote Sens. Environ. 91, 332–344.

Author Response

Ms. Yulia Zhu

Assistant Editor, MDPI, Remote sensing

We wish to thank you and all four reviewers for the valuable feedback. We have addressed each of the reviewers’ comments in turn. However, reviewer 4 prompts an additional revision. We include a letter presenting our responses (included in green font) to each of the points raised. The changes made to the manuscript are also included in green font for ease of reference. We hope that this improved version can be reconsidered for publication in the prestigious journal Remote sensing and will be of value to the scientific community.

Yours sincerely,

Dr. M. Pompa-García, on behalf of all coauthors

Reviewer 4:

Open Review

The authors have addressed most of my concerns, so I think it can be published after some minor revisions.

Since the remote sensing NDVI is used to represent vegetation productivity. The impacts of data noise in the AVHRR and MODIS data time series may impact the analysis. So this issue should be included in the Section of Discussion, some references maybe help:

[1] Chen, J.M., Deng, F., Chen, M., 2006. Locally adjusted cubic-spline capping for reconstructing seasonal trajectories of a satellite-derived surface parameter. IEEE Trans. Geosci. Remote Sens. 44, 2230–2237

[2] Chu Dong, Shen Huanfeng, et. al., Long time-series NDVI reconstruction in cloud-prone regions via spatio-temporal tensor completion. Remote Sensing of Environment. 264. 2021.

[3] Chen, J., Jonsson, ¨ P., Tamura, M., Gu, Z., Matsushita, B., Eklundh, L., 2004. A simple method for reconstructing a high-quality NDVI time-series data set based on the Savitzky-Golay filter. Remote Sens. Environ. 91, 332–344.

Dear reviewer,

Thank you very much for the references provided. We have strengthened the discussion in response to your recommendations. See lines 518-523.

Author Response File: Author Response.pdf